Manufacturer Support Before You Order

Turn the Gas Stream Into a Comparable Equipment Proposal

The useful output of an inquiry is not a generic tower price. XICHENG reviews the available process data and defines the preliminary contact method, construction material, package boundary and information still needed before final sizing.

Application reviewWe screen gas composition, airflow, temperature, operating pattern and outlet requirement before recommending a configuration.

Custom fabricationPP and FRP construction can be configured around the selected chemistry, connections, access needs and available footprint.

Purchase documentsThe proposal can identify included equipment, selected options, design basis and the drawings or documents available for the order.

Factory visibilityReview an actual spray-tower product display and current scrubber fabrication images before sending project data.

Wet Scrubber Fabrication and Installation Examples

These images show XICHENG wet-scrubber construction and installed system arrangements. The final acid-fume system may use a different vessel count, duct route, fan or control package based on the project.

Request an Acid Fume Scrubber Proposal

A PP plastic sheet — also called a polypropylene sheet, PP solid sheet board, or industrial plastic sheet — is a flat thermoplastic semi-finished material manufactured by extrusion or compression molding from PP (polypropylene), PPs (flame-retardant PP), PVC (polyvinyl chloride), or FRP (fiberglass reinforced plastic) for fabrication into chemical tanks, ductwork, fume hoods, pickling tanks, and corrosion-resistant equipment. Unlike metal sheet that corrodes and requires coating, a PP sheet provides inherent chemical resistance through the full thickness of the material — cut edges, drilled holes, and welded joints are as corrosion-resistant as the sheet surface. XICHENG EP supplies PP, PPs, PVC, and FRP sheets and plates in thicknesses from 2 mm to 50 mm, standard sheet sizes of 1,220 × 2,440 mm and 1,500 × 3,000 mm, with custom sizing and CNC cutting available.

Industrial plastic sheets serve as the raw material for fabricating the entire corrosion-resistant equipment range: a 10 mm PP sheet is cut, bent, and hot-gas welded to form a pickling tank; a 6 mm PVC sheet is bonded to form a laboratory fume hood liner; a 3 mm FRP sheet is laminated over a mold to form a centrifugal fan housing. The sheet material choice determines the chemical resistance, temperature range, and mechanical strength of the finished equipment. XICHENG EP stocks standard sheet grades for immediate dispatch and can compound custom colors (grey, black, blue, green), UV-stabilized formulations, and flame-retardant grades (UL 94 V-0) with a 7-10 day lead time. All sheets are supplied with material certification per ISO 1183 (density), ISO 527 (tensile properties), and ISO 179 (impact strength).

Plastic Sheet & Board Range

PP Solid Sheet

A PP solid sheet — also called a polypropylene sheet or PP solid sheet board — is an extruded flat sheet of polypropylene copolymer (PP-C) or homopolymer (PPH) with a smooth, non-porous surface on both faces, used as the primary fabrication material for chemical tanks, ductwork, and corrosion-resistant equipment. The sheet is produced by feeding PP resin pellets through a screw extruder, passing the melt through a flat sheet die, and calendering between polished rollers to achieve a thickness tolerance of ±5% (standard) or ±3% (precision grade). PP sheet is available in natural (translucent white), grey (RAL 7032), and black (2% carbon black UV-stabilized) colors.

PP solid sheet offers the best cost-to-performance ratio of any corrosion-resistant sheet material: it resists hydrochloric acid (all concentrations at ≤70°C), sulfuric acid (≤80% at ≤70°C), sodium hydroxide (≤50% at ≤70°C), and most salt solutions. A 10 mm PP sheet has a tensile strength of 25-32 MPa, flexural modulus of 1,200-1,500 MPa, and density of 0.91 g/cm³ — approximately 60% lighter than PVC and 80% lighter than steel of equivalent thickness. Standard sheet size is 1,220 × 2,440 mm and 1,500 × 3,000 mm, with thicknesses from 2 mm to 50 mm. PP sheet is joined by hot-gas welding (DVS 2207-3), extrusion welding (DVS 2207-4), or butt-fusion welding using PP welding rod of matching grade.

PP Plate

A PP plate sheet — also called a polypropylene plate or PP plastic plate — is a thick-section PP sheet, typically 15 mm to 50 mm, used for structural applications requiring higher stiffness and load-bearing capacity than standard sheet gauges. The distinction between “sheet” and “plate” is primarily thickness: PP sheet covers 2-15 mm for general fabrication; PP plate covers 15-50 mm for structural base plates, tank floors, equipment mounting pads, and components subjected to bolt tension or compressive loading. PP plate is produced by the same extrusion process as sheet with extended cooling and annealing to relieve internal stresses that would cause warping during machining.

PP plate is machined using standard woodworking or metalworking tools — carbide-tipped saw blades, router bits, and drills — with the same machining parameters as aluminum (feed rates of 0.1-0.3 mm/tooth, spindle speeds of 3,000-6,000 RPM). The machined surface has a matte finish that bonds well with adhesives and accepts hot-gas welding without surface preparation beyond solvent wiping (isopropyl alcohol). PP plate at 20 mm thickness has a flexural modulus of 1,500 MPa — approximately equivalent to 2.5 mm of structural steel in bending stiffness — making it suitable for equipment support structures and tank base frames where metal would corrode. PP plate is also used as a sacrificial wear surface in chutes, hoppers, and abrasive slurry handling where the low coefficient of friction (0.25-0.30 against steel) reduces material hang-up.

FRP Sheet/Board

An FRP sheet — also called an FRP board or fiberglass reinforced panel — is a flat composite laminate made from glass fiber reinforcement (E-glass mat, woven roving, or continuous strand) impregnated with a thermoset resin matrix (polyester, vinyl ester, or novolac vinyl ester). The sheet is produced by hand lay-up or continuous lamination, cured under controlled temperature and humidity, and post-cured to ensure full chemical crosslinking of the resin. FRP sheet is specified for applications requiring higher strength (tensile 80-120 MPa), higher temperature resistance (up to 95°C for vinyl ester, 120°C for novolac VE), or fire-retardant properties (ASTM E84 Class 1 with brominated resin) beyond the capabilities of unreinforced thermoplastics.

FRP sheet is the base material for fabricating highly stressed corrosion-resistant components: fan housings, pump casings, scrubber shells, tank walls, and structural platforms in chemical plants. The laminate construction includes a resin-rich corrosion barrier (2.5-3.0 mm, 90% resin, surfacing veil) on the process-contact face and a structural layer (balance of thickness, 35-45% glass) for mechanical strength. FRP sheet is cut with diamond-grit or carbide-grit blades (not standard toothed blades which fray the glass fibers) and joined by laminating — applying additional layers of resin and glass mat over the joint to create a seamless chemical bond. Standard sheet sizes are 1,220 × 2,440 mm and 1,000 × 2,000 mm with thicknesses from 2 mm to 30 mm. FRP sheet is 30-40% more expensive than PP sheet of equivalent thickness but provides 3-4× the strength and 20-30°C higher temperature capability.

PPs Flame-Retardant Sheet

A PPs sheet — also called a flame retardant PP sheet or PPs flame retardant board — is a polypropylene sheet compounded with halogen-free intumescent flame retardant additives to achieve UL 94 V-0 classification (self-extinguishing within 10 seconds on a vertical specimen, no flaming drips). Standard PP sheet is classified UL 94 HB (horizontal burn); PPs sheet achieves V-0 by incorporating 15-25% ammonium polyphosphate or magnesium hydroxide into the PP matrix, which releases water vapor and forms a protective char layer when exposed to flame, starving the combustion zone of oxygen and fuel. The flame retardant additives do not contain bromine, chlorine, or antimony trioxide, making PPs sheet compliant with EU RoHS and WEEE directives for electronic and electrical equipment applications.

PPs sheet retains approximately 85-90% of the mechanical properties of standard PP sheet — the flame retardant filler reduces tensile strength by 10-15% (to 22-28 MPa) and impact strength by 15-20% — and full chemical resistance to acids, alkalis, and solvents equivalent to standard PP. The sheet is identified by its dark grey or black color (natural PPs color from the flame retardant compound) and is available in thicknesses from 3 mm to 25 mm. PPs sheet is specified for semiconductor wet bench enclosures, battery formation room ventilation ductwork, chemical storage cabinet construction, and any application where fire propagation along surfaces must be prevented per NFPA, FM Global, or local fire codes. The sheet is welded using PPs-compatible welding rod — standard PP welding rod will not achieve the same flame rating as the base sheet.

PVC Sheet

A PVC plastic sheet — also called a PVC rigid sheet or PVC sheet board — is an extruded flat sheet of unplasticized polyvinyl chloride (PVC-U), distinguished from PP sheet by its higher rigidity (flexural modulus 2,500-3,000 MPa vs. 1,200-1,500 MPa for PP), higher density (1.40-1.45 g/cm³ vs. 0.91 for PP), and excellent chemical resistance to oxidizing acids, alkalis, and salt solutions at temperatures up to 60°C. PVC sheet is naturally flame-retardant (UL 94 V-0 without additives) due to the chlorine content (approximately 57% Cl by weight) which releases HCl gas when heated, quenching the combustion reaction. This inherent fire resistance makes PVC the standard material for laboratory furniture, fume hood liners, and cleanroom wall panels in facilities where fire code compliance is mandatory.

PVC sheet is joined by solvent cement bonding (THF-based solvent cement dissolves the PVC surface, creating a molecular weld without heat) or hot-gas welding using PVC welding rod at 220-260°C. Solvent cement joints achieve 80-90% of the base sheet tensile strength within 24 hours of curing, and the process requires no specialized welding equipment — only a brush applicator and adequate ventilation for solvent vapors. PVC sheet is available in grey (RAL 7011, standard industrial grade), white, and clear (transparent PVC for sight glasses and enclosure windows) in thicknesses from 1 mm to 30 mm. PVC is NOT suitable for contact with aromatic solvents (toluene, xylene), ketones (acetone, MEK), or esters, which dissolve or craze the PVC surface.

PP/PVC Welding Rod

A PP welding rod — also called a PVC welding rod or plastic welding rod — is a round, triangular, or twin-strand extruded filler material made from the same thermoplastic grade as the base sheet (PP, PPs, PVC, PVDF, or PE), used as the filler metal equivalent in hot-gas and extrusion welding of plastic fabrications. The welding rod is fed into the joint by hand (manual hot-gas welding per DVS 2207-3) or automatically by an extrusion welder (per DVS 2207-4), where it is melted by a stream of heated air (260-350°C for PP, 220-260°C for PVC) and fused with the softened base sheet surface to create a homogeneous weld bead. The rod diameter is selected to match the sheet thickness and joint geometry: 3-4 mm round rod for sheet ≤8 mm, 5-6 mm for sheet 8-20 mm, and 4-5 mm triangular rod for multi-pass V-groove welds in thick sections.

Welding rod must match the base sheet material grade exactly — PP rod for PP sheet, PPs rod for PPs sheet, PVC rod for PVC sheet — because the weld strength depends on molecular interdiffusion between the molten rod and the molten sheet surface. A mismatched rod (e.g., PP rod on PVC sheet) will not fuse and the weld will peel apart under load. XICHENG EP supplies PP, PPs, and PVC welding rods in coils of 5 kg or spools of 1 kg, in 3 mm, 4 mm, and 5 mm diameters, round and triangular profiles, with each batch traceable to the resin lot and documented by a material certificate. Welding rod should be stored in sealed polyethylene bags in a dry, dust-free environment — PVC rod absorbs atmospheric moisture which creates porosity (bubbles) in the weld bead, and PP rod surface oxidation from prolonged storage degrades weld strength.

Plastic Sheet Material Selection

Frequently Asked Questions

What is the difference between PP sheet and PVC sheet?

PP sheet is lighter (0.91 vs. 1.42 g/cm³), more flexible (flexural modulus 1,200 vs. 2,800 MPa), and has a higher continuous service temperature (70°C vs. 60°C). PVC sheet is stiffer, inherently flame-retardant (UL 94 V-0 without additives), and can be joined by solvent cementing — no hot-gas welding equipment required. PP is preferred for chemical tank fabrication and ductwork where its weldability and broad chemical resistance are the primary requirements. PVC is preferred for laboratory furniture, fume hood liners, and cleanroom panels where fire rating and solvent-cement joinery simplify assembly. PVC cannot be used with aromatic solvents or ketones; PP cannot be used with concentrated nitric acid or strong oxidizing agents.

What welding rod do I need for PP sheet?

Use PP welding rod of the same material grade as the sheet — PP-C rod for PP-C sheet, PPs rod for PPs sheet. The rod diameter should be 3-4 mm for sheet thicknesses up to 8 mm and 5-6 mm for 8-20 mm sheet. Triangular profile rod is preferred for multi-pass V-groove welds because the pointed tip seats into the root of the V and allows better penetration. Always store welding rod in sealed polyethylene bags — surface oxidation and dust contamination are the leading causes of weak, porous welds in PP fabrication.

Can PP and PVC be welded together?

No — PP and PVC are chemically incompatible thermoplastics and cannot be fusion-welded to each other. The two materials are from different polymer families (polyolefin vs. vinyl) and do not intermix at the molecular level when melted. For equipment requiring both materials, mechanical fastening with PP or PVC bolts through flanged joints or gasketed connections is the standard joining method, or a flexible EPDM connector can bridge between PP and PVC duct sections.

Get a Plastic Sheet Quote

XICHENG EP stocks PP, PPs, PVC, and FRP sheets and plates in standard sizes from 2 mm to 50 mm thickness, with PP and PVC welding rods in matching grades. Every shipment includes a material certificate (ISO 1183, ISO 527, ISO 179) and a lot traceability document. Contact our sales team with your material, thickness, sheet size, and quantity requirements for a stock availability check and quotation within 24 hours. Custom sheet sizing and CNC routing services are available.

About XICHENG EP

XICHENG EP LTD is an industrial air pollution control equipment manufacturer with 16+ years of production experience, 2,600+ systems shipped, and installations in 60+ countries. We manufacture in China, with in‑house PP sheet extrusion, CNC cutting, hot‑gas welding, and FRP filament winding — every scrubber component from raw material to finished vessel is fabricated under one roof. No outsourced fabrication, no subcontractor delays.

Certifications and Compliance

• CE Marking — Machinery Directive 2006/42/EC, EMC Directive 2014/30/EU
• RoHS — 2011/65/EU compliant materials throughout
• ISO 9001:2015 — Quality management system
• ISO 14001:2015 — Environmental management system
• SGS material testing — PP sheet, FRP laminate, weld integrity verified
• Design basis per EU 2010/75/EU Industrial Emissions Directive
• Engineered to meet US EPA NESHAP and OSHA 1910.94

How to Order

1. Send your operating data: Gas flow rate (CFM or m³/hr), contaminant type and inlet concentration (ppm), required outlet limit per your permit, gas temperature, and available site footprint. Contact our engineering team
2. Receive your proposal: Within 48 hours — preliminary sizing, process flow diagram, budget price, and delivery timeline. No obligation
3. Review and approve: Once the proposal meets your requirements, we issue a formal quotation with detailed technical specifications
4. Drawing approval: P&ID, general arrangement, and electrical schematic for your sign‑off before fabrication begins
5. Manufacturing and testing: 6‑10 weeks fabrication. Pre‑shipment water‑tightness test, recirculation test, and control system checkout
6. Shipping and commissioning: Containerized sea freight or air freight worldwide. Remote commissioning support via video call included; optional on‑site supervision available

Global Shipping

We ship wet scrubber systems worldwide from our manufacturing facility in China. Regular containerized sea freight to ports in North America (Los Angeles, Houston, New York), Europe (Rotterdam, Hamburg, Antwerp), the Middle East (Jebel Ali, Dammam), Southeast Asia (Singapore, Port Klang), and Australia (Sydney, Melbourne). Air freight available for urgent deliveries and smaller systems. All equipment is crated, shrink‑wrapped, and container‑loaded with desiccant for ocean transit.

A PP industrial valve — also called a polypropylene valve or plastic industrial valve — is a corrosion-resistant fluid control device manufactured from PP (polypropylene), PPH, or FRP (fiberglass reinforced plastic) for on/off isolation, flow regulation, and backflow prevention in chemical process piping, laboratory exhaust systems, water treatment, and electroplating lines. Unlike metal valves that corrode internally within months in acid or chloride service, a PP valve maintains full mechanical integrity and bubble-tight shutoff across its entire 10-15 year service life without protective coatings, cathodic protection, or scheduled replacement. XICHENG EP manufactures PP ball valves, butterfly valves, check valves, FRP valves, VAV/CAV air volume control valves, and industrial plastic valves in sizes from DN15 (1/2″) to DN300 (12″), with flanged, threaded, socket-weld, and butt-weld end connections per DIN, ANSI, and JIS standards.

The PP material choice eliminates three failure modes that plague metal valves in corrosive service: stem corrosion and seizure (PP stem + PTFE seat = zero corrosion torque), body perforation from internal pitting (PP is immune to chloride pitting and acid attack), and seat leakage from chemical degradation (EPDM or FPM seats provide full chemical compatibility). PP valves are approximately 60% lighter than equivalent 316L stainless steel valves — a DN100 PP ball valve weighs 5.7 kg vs. 16 kg for 316L — reducing pipe support requirements and installation labor. All XICHENG EP industrial valves are factory pressure-tested at 1.5× design pressure per API 598 and supplied with material certification and a 1-year warranty.

Industrial Valve Product Range

PP Ball Valve

A PP ball valve — also called a polypropylene ball valve or PP industrial ball valve — is a quarter-turn shutoff valve with a PP body, a spherical PP or PVDF ball with a full-bore or reduced-bore flow passage, and PTFE seat rings that seal against the ball in both the open and closed positions. Rotating the stem 90° aligns the ball bore with the pipe axis (open) or presents the solid ball face to the flow (closed), providing full shutoff with a pressure rating up to PN10 (10 bar / 150 psi) at 20°C. The PP body is injection-molded in two or three pieces and joined by butt-welding or bolted flanges with an EPDM or FPM O-ring body seal.

PP ball valves are the most common valve type in corrosive fluid systems because of their simple, reliable operation and low pressure drop — the full-bore design provides essentially zero additional flow resistance when open, with a Cv (flow coefficient) typically 10-20% higher than an equivalent globe valve. Double-union (true union) PP ball valves allow the valve body to be removed from the pipeline without cutting or unbolting the pipe connections — the end connectors (socket, threaded, or flanged) remain attached to the pipe while the center body section with the ball and seats is lifted out for inspection or replacement. Sizes from DN15 (1/2″) to DN100 (4″) in single-union, double-union, and flanged configurations.

PP Butterfly Valve

A PP butterfly valve — also called a polypropylene butterfly valve or PPH butterfly valve — is a quarter-turn throttling and shutoff valve with a PP body, a circular PP or PVDF disc mounted on a central shaft, and an EPDM or FPM seat liner that forms the seal between the disc edge and the body when closed. When the disc rotates 90° to align with the flow axis, the valve presents a very low obstruction — approximately 80-90% of the full pipe cross-section remains open — giving butterfly valves the highest flow capacity per unit weight of any valve design.

PP butterfly valves are the standard choice for larger-diameter piping (DN65 and above) where a ball valve of equivalent size becomes disproportionately heavy and expensive. A DN150 (6″) PP butterfly valve weighs approximately 4 kg and costs about 40% of an equivalent PP ball valve, making it the economic choice for main header isolation, pump suction/discharge isolation, and tank drain lines. The lever handle with a locking quadrant provides positive position indication and allows partial opening for throttling service, though butterfly valves are most commonly used for on/off isolation. An electric or pneumatic actuator can replace the manual handle for remote operation. Sizes from DN50 (2″) to DN300 (12″) in wafer (sandwiched between flanges) or lug (bolted to one flange) body styles.

FRP Valve

An FRP valve — also called a corrosion resistant FRP valve or fiberglass valve — uses a fiberglass-reinforced vinyl ester or polyester resin body and internal components for applications where PP lacks the temperature resistance or mechanical strength required by the process. FRP valves operate at fluid temperatures up to 95°C (vinyl ester) or 120°C (novolac VE) — approximately 25-50°C higher than PP — and the glass fiber reinforcement provides 3-4× the tensile strength of unreinforced PP at equivalent wall thickness. The FRP body is fabricated by compression molding or filament winding with a resin-rich corrosion barrier (2.5 mm, 90% resin) at all wetted surfaces.

FRP ball valves and butterfly valves are specified for hot acid transfer lines, chlor-alkali plant brine and caustic piping, flue gas desulfurization slurry systems, and any application where a metal valve would require exotic alloy construction (Hastelloy C, titanium) to survive the chemical environment. An FRP ball valve with a PVDF ball, PTFE seats, and a vinyl ester body handles hydrochloric acid up to 18% at 80°C, sulfuric acid up to 50% at 80°C, and wet chlorine gas condensate at 60°C — conditions that would embrittle PP and pit 316L stainless steel. PureFlex and Conley Composites (Andronaco Industries) are established FRP valve suppliers alongside XICHENG EP’s custom-engineered FRP valve range for DN15-DN200.

PP Check Valve

A PP check valve — also called a polypropylene check valve or PP non-return valve — is a one-way valve that allows fluid flow in the forward direction and automatically closes to prevent reverse flow when the downstream pressure exceeds the upstream pressure or the pump stops. The PP body houses a PP disc, ball, or swing gate that is lifted off its seat by forward flow and pressed back onto the seat by reverse flow or gravity, providing passive backflow prevention without any external actuation or power source.

PP check valves protect centrifugal pumps from reverse rotation damage during power failure, prevent tank drainage through the fill line if the pump loses prime, and isolate chemical feed lines from process backflow. Three internal designs cover different applications: a spring-loaded PP disc check valve closes quickly (0.1-0.5 seconds) and is suitable for vertical or horizontal installation; a swing check valve with a PP flapper and no spring has the lowest pressure drop and is installed in horizontal lines only; a ball check valve with a PP or EPDM-coated ball is specified for viscous or solids-laden fluids where a disc or swing mechanism might jam. Sizes from DN15 to DN150 with socket-weld, threaded, or flanged ends. The cracking pressure (minimum forward pressure to open) is 0.05-0.1 bar for spring-loaded and 0.02-0.05 bar for swing checks.

Plastic Industrial Valve

A plastic industrial valve — also called an industrial plastic valve or plastic chemical valve — is the broad-category term for thermoplastic valves (PP, PPH, PVDF, PVC, CPVC) used in industrial fluid handling where corrosion resistance is the primary material selection criterion. The term encompasses ball valves, butterfly valves, check valves, diaphragm valves, globe valves, and gate valves, each available in the full range of thermoplastic materials to match the specific chemical environment and temperature range of the process. A single chemical plant may use PP ball valves on ambient acid lines, PVDF ball valves on solvent lines, and CPVC butterfly valves on hot caustic lines — all from the same valve manufacturer for consistent dimensions, pressure ratings, and spare parts.

Plastic industrial valves are manufactured to the same dimensional standards as metal valves — face-to-face dimensions per DIN 3202 or ANSI B16.10, flange drilling per DIN PN10/16 or ANSI B16.5 150 lb — so a PP ball valve drops into the same pipeline as a 316L stainless steel ball valve without modifying the pipe flanges. XICHENG EP supplies the full range of thermoplastic industrial valves in PP, PPH, PVDF, and FRP materials for process temperatures from -10°C to 120°C depending on the material selection. Each valve type and material combination is verified against the customer’s chemical environment using the ISO/TR 10358 chemical resistance database and XICHENG EP’s 16 years of field application data.

VAV Valve (Variable Air Volume)

A VAV valve — also called a variable air volume valve or Venturi air valve — is an airflow control device installed in laboratory fume hood exhaust ductwork that modulates the exhaust air volume in response to the fume hood sash position, maintaining constant face velocity (0.4-0.6 m/s) regardless of whether the sash is fully open, partially open, or closed. The VAV valve uses a pressure-independent Venturi or butterfly mechanism with a fast-response electric actuator (2-5 second full-stroke time) linked to a sash position sensor or a duct velocity pressure transmitter. When the sash is lowered, the valve partially closes to reduce exhaust volume; when the sash is raised, the valve opens to increase exhaust volume. This modulation saves 40-60% of the fan and HVAC energy compared to a constant-volume system that exhausts the full design airflow at all times.

PP construction of the VAV valve body is essential for corrosive fume hood exhaust — the valve is installed in the duct carrying acid fumes, solvent vapors, and humid exhaust that would corrode a galvanized steel or aluminum valve within 12-24 months. The PP valve body with a PP or PVDF throttle plate, PTFE shaft bearings, and an EPDM or FPM blade seal maintains accurate flow control (±5% of setpoint) across a 10:1 turndown ratio (10-100% of design flow). A factory-calibrated airflow measurement station integrated into the valve body provides a 0-10V or 4-20 mA signal to the building management system for monitoring and alarm purposes. Standard sizes from DN150 to DN315 for fume hood exhaust volumes of 500-3,000 m³/h per hood.

CAV Valve (Constant Air Volume)

A CAV valve — also called a constant air volume valve or constant volume Venturi valve — is a self-regulating airflow control device that maintains a fixed exhaust or supply air volume regardless of duct pressure fluctuations, without external power, sensors, or control signals. The CAV valve uses a spring-loaded throttle cone or diaphragm inside a Venturi-shaped PP body: as duct pressure increases, the cone moves forward into the Venturi throat, restricting the flow area and maintaining a constant volume setpoint. The setpoint is factory-calibrated or field-adjustable by changing the spring preload, typically over a range of 50-100% of the valve’s rated flow. CAV valves are the standard specification for constant-volume fume hood exhaust, general laboratory ventilation, and supply air terminals where simplicity, reliability, and zero energy consumption are prioritized over the energy savings of VAV control.

The PP CAV valve body with a PP throttle cone, stainless steel spring isolated from the air stream by a PTFE diaphragm, and EPDM seals maintains setpoint within ±10% across a duct pressure range of 50-750 Pa. Unlike a motorized damper, there is no actuator to fail, no wiring to install, and no control signal to commission — the valve is purely mechanical and will maintain its setpoint for the life of the building with zero maintenance beyond an annual inspection. CAV valves are sized for constant exhaust volumes of 200-5,000 m³/h per hood or zone, in PP or PPs (flame-retardant) construction for corrosive fume hood exhaust or stainless steel for non-corrosive laboratory supply air. XICHENG EP CAV valves are factory-calibrated to the specified airflow setpoint and supplied with a calibration certificate traceable to ISO 5167.

Industrial Valve Material Selection

Frequently Asked Questions

What is the difference between VAV and CAV valves?

A VAV (Variable Air Volume) valve modulates airflow in response to a control signal — typically from a fume hood sash position sensor — to maintain constant face velocity while reducing exhaust volume when the sash is closed, saving 40-60% of fan energy. A CAV (Constant Air Volume) valve is a purely mechanical, self-regulating device that maintains a fixed airflow setpoint regardless of duct pressure fluctuations, without any external power, sensors, or control wiring. VAV valves are specified for multi-hood laboratories with diversity in hood usage; CAV valves are specified for standalone hoods, constant-volume laboratories, and applications where the energy savings of VAV do not justify the added controls complexity.

What end connections are available for PP valves?

PP valves are available with four standard end connection types: socket-weld (plain socket for solvent-free hot-gas welding to PP pipe, sizes DN15-DN110), butt-weld (plain end with matching pipe OD for butt-fusion welding, sizes DN15-DN300), threaded (BSP or NPT female threads with a PP or metal thread insert, sizes DN15-DN50), and flanged (PP loose-ring flange with a galvanized steel or SS316 backing ring drilled to DIN PN10 or ANSI 150 lb, sizes DN15-DN300). Double-union ball valves combine a socket or threaded end connector with a removable valve body for inline serviceability.

Can PP valves be used with compressed air or gas?

PP valves are rated for liquid service up to PN10 (10 bar / 150 psi) at 20°C. For compressed air or gas service, the pressure rating is derated to PN6 (6 bar / 90 psi) due to the higher stored energy of compressed gas and the risk of brittle failure if the valve body is impacted while pressurized. PP valves in compressed gas service should be protected from mechanical impact (guards or enclosures) and should not be used for oxygen service unless specifically cleaned and certified for oxygen use, as PP can ignite in pure oxygen under adiabatic compression conditions.

Get an Industrial Valve Quote

XICHENG EP manufactures PP, PPH, PVDF, and FRP industrial valves — ball, butterfly, check, VAV, and CAV types — in sizes from DN15 to DN300. Every valve is factory pressure-tested to API 598 and supplied with material certification, a dimensional drawing, and a 1-year warranty. Contact our application engineers with your pipe material, chemical environment, operating temperature and pressure, and required flow coefficient (Cv or Kv) for a valve selection and quotation within 48 hours.

About XICHENG EP

XICHENG EP LTD is an industrial air pollution control equipment manufacturer with 16+ years of production experience, 2,600+ systems shipped, and installations in 60+ countries. We manufacture in China, with in‑house PP sheet extrusion, CNC cutting, hot‑gas welding, and FRP filament winding — every scrubber component from raw material to finished vessel is fabricated under one roof. No outsourced fabrication, no subcontractor delays.

Certifications and Compliance

• CE Marking — Machinery Directive 2006/42/EC, EMC Directive 2014/30/EU
• RoHS — 2011/65/EU compliant materials throughout
• ISO 9001:2015 — Quality management system
• ISO 14001:2015 — Environmental management system
• SGS material testing — PP sheet, FRP laminate, weld integrity verified
• Design basis per EU 2010/75/EU Industrial Emissions Directive
• Engineered to meet US EPA NESHAP and OSHA 1910.94

How to Order

1. Send your operating data: Gas flow rate (CFM or m³/hr), contaminant type and inlet concentration (ppm), required outlet limit per your permit, gas temperature, and available site footprint. Contact our engineering team
2. Receive your proposal: Within 48 hours — preliminary sizing, process flow diagram, budget price, and delivery timeline. No obligation
3. Review and approve: Once the proposal meets your requirements, we issue a formal quotation with detailed technical specifications
4. Drawing approval: P&ID, general arrangement, and electrical schematic for your sign‑off before fabrication begins
5. Manufacturing and testing: 6‑10 weeks fabrication. Pre‑shipment water‑tightness test, recirculation test, and control system checkout
6. Shipping and commissioning: Containerized sea freight or air freight worldwide. Remote commissioning support via video call included; optional on‑site supervision available

Global Shipping

We ship wet scrubber systems worldwide from our manufacturing facility in China. Regular containerized sea freight to ports in North America (Los Angeles, Houston, New York), Europe (Rotterdam, Hamburg, Antwerp), the Middle East (Jebel Ali, Dammam), Southeast Asia (Singapore, Port Klang), and Australia (Sydney, Melbourne). Air freight available for urgent deliveries and smaller systems. All equipment is crated, shrink‑wrapped, and container‑loaded with desiccant for ocean transit.

A pickling tank — also called a polypropylene pickling tank, PP acid pickling tank, or FRP pickling tank — is a corrosion-resistant immersion vessel engineered for the chemical surface treatment of metals: removing mill scale, rust, and oxide layers from steel, stainless steel, copper, and aluminum prior to galvanizing, electroplating, or coating. The tank is fabricated from PP (polypropylene) or FRP (fiberglass reinforced plastic) sheet using hot-gas extrusion welding (PP) or hand lay-up (FRP), providing full resistance to hydrochloric acid (5-18%), sulfuric acid (5-15%), nitric-hydrofluoric mixed acids, and alkaline degreasing solutions at operating temperatures from ambient to 95°C depending on material selection.

XICHENG EP manufactures pickling tanks in sizes from 100-liter bench-top laboratory units to 20,000-liter industrial immersion lines, with wall thicknesses from 10 mm to 30 mm engineered for hydrostatic load plus a 2× safety factor. Standard features include an integral PP spill containment lip, a bottom drain with PP flange and valve, lifting lugs, and external PP rib stiffeners at 500-800 mm centers for tanks exceeding 1,200 mm in any dimension. Multi-compartment tanks with internal PP baffle walls allow sequential pickling, rinsing, and passivation in a single tank unit, reducing floor space by 30-40% compared to individual tanks. All XICHENG EP pickling tanks are factory hydro-tested at 1.3× design liquid level before shipment.

Pickling Tank Product Range

PP Pickling Tank

A PP pickling tank — also called a polypropylene pickling tank or PPH pickling tank — is the standard choice for acid pickling of steel and stainless steel components at temperatures up to 70°C. The tank is fabricated from 10-25 mm PP or PPH (polypropylene homopolymer) sheet, cut to size on a CNC panel saw, and joined by hot-gas extrusion welding using PP welding rod of the same grade as the base material. The resulting monocoque structure has no metal reinforcement in contact with the process liquid — the corrosion-resistant envelope is continuous from the tank floor to the rim.

PP pickling tanks handle hydrochloric acid (5-18% at 25-60°C), sulfuric acid (5-15% at 25-70°C), phosphoric acid, and mixed nitric-hydrofluoric acid pickling solutions used for stainless steel. The tank interior is smooth with radiused corners (minimum 25 mm radius at all wall-to-wall and wall-to-floor joints) to eliminate crevices where sludge accumulates. External PP vertical rib stiffeners at 500 mm centers provide structural rigidity without internal obstructions that would trap air pockets during filling. For tanks deeper than 1,500 mm, the wall thickness steps up in 5 mm increments per 500 mm of depth to match the increasing hydrostatic pressure.

FRP Pickling Tank

An FRP pickling tank — also called a fiberglass pickling tank or fiberglass reinforced plastic pickling tank — is specified for pickling processes operating at elevated temperatures (70-95°C) or using aggressive mixed acids that degrade PP. The tank laminate uses a chemical-grade vinyl ester resin with E-glass mat and woven roving reinforcement, with a resin-rich corrosion barrier (2.5-3.0 mm, 90% resin content) at the process-contact surface backed by a structural layer (6-20 mm, 35-45% glass content) that provides the mechanical strength. The hand lay-up or filament winding fabrication produces a seamless, joint-free tank shell with integrated flange, nozzle, and stiffener geometry molded in place.

FRP pickling tanks handle the full range of pickling acids at temperatures that would soften and deform PP: sulfuric acid up to 50% at 80°C, hydrochloric acid up to 18% at 85°C, and nitric-hydrofluoric mixed acid at 50-60°C. The FRP laminate is inherently fire-retardant (ASTM E84 Class 1 with brominated resin additive) and provides approximately 3× the tensile strength of PP at equivalent thickness. FRP tanks exceeding 3,000 mm in length or height include external carbon steel or FRP structural frames to limit deflection under hydrostatic load to L/200 (span/200). FRP pickling tanks are the standard specification in steel mill push-pickling lines and tube pickling operations where operating temperature and mechanical loads exceed PP capabilities.

PP Electroplating Tank

A PP electroplating tank — also called an electroplating pickling tank or plastic plating tank — is a PP fabrication designed for the electroplating process sequence: acid pickling, alkaline degreasing, electroplating (nickel, chromium, zinc, copper, tin), and post-plate rinsing. Unlike a simple pickling tank, an electroplating tank includes provisions for anode and cathode bus bars mounted along the tank rim, heating elements or heat exchanger coils for bath temperature control (typically 40-65°C), and air sparging or mechanical agitation for bath uniformity. The PP material provides electrical insulation between the tank and the plating bath, eliminating stray current corrosion that occurs with metal tanks.

Standard electroplating tank configurations include single-compartment tanks for a dedicated plating bath and multi-compartment tanks where the pickling, plating, and rinsing stages share a common PP shell with internal PP divider walls. Multi-compartment designs reduce inter-stage pipework and are standard for automated plating lines where a single transfer mechanism indexes parts through the sequence. Electroplating tanks are fabricated from 10-20 mm PP sheet with a minimum 15 mm wall thickness when heating elements are immersed in the bath. External PP structural reinforcement is spaced at 400-600 mm centers for the additional load of solution weight plus the dynamic load of part immersion and removal.

Acid Etching Tank

An acid etching tank — also called a PP etching tank or acid etching tank PP — is a PP or FRP vessel specifically designed for the chemical etching of metal surfaces using aggressive acid mixtures: ferric chloride (for copper and stainless steel etching), nitric-hydrofluoric acid (for titanium and aluminum etching), and cupric chloride (for printed circuit board etching). Etching tanks require precise temperature control — typically within ±2°C — because etch rate is strongly temperature-dependent, varying by 10-15% per degree Celsius for most etch chemistries. PP is the standard material for etching tanks operating below 60°C; FRP with vinyl ester resin is specified for nitric-HF and higher-temperature etch processes.

Etching tanks include an integral PP heating/cooling coil or external heat exchanger loop with a PP circulation pump to maintain the ±2°C setpoint. The tank lid is gasketed with EPDM or FPM and includes an exhaust port connected to a fume scrubber system — essential for nitric acid etching which generates NOx fumes. For PCB etching applications, the tank includes a titanium or PP spray bar array for even etchant distribution over the board surface. XICHENG EP etching tanks are supplied with a process-specific chemical resistance verification for the specified etchant composition, concentration, and operating temperature.

Steel Pickling Tank

A steel pickling tank — also called a pickling tank for steel or steel strip pickling tank — is a heavy-duty PP or FRP immersion vessel sized for the pickling of steel coils, wire rod, tubes, and fabricated components in hydrochloric or sulfuric acid at volumes from 2,000 to 20,000 liters. The tank is designed for continuous or batch operation with provisions for acid circulation through an external PP heat exchanger that maintains the pickling bath at 60-85°C, where the pickling rate is 3-5× faster than at ambient temperature. An integral PP fume extraction lip around the tank perimeter captures acid mist and directs it to a fume scrubber, maintaining workplace air quality below the OSHA PEL of 5 ppm for HCl.

Steel pickling tanks in continuous strip lines incorporate submerged PP guide rolls or slide bearings for steel strip passage through the tank at line speeds up to 200 m/min. The tank floor is sloped 1-2% toward the drain with a PP sediment trap for mill scale sludge collection. For push pickling lines — where individual coils are pushed through the tank by a hydraulic ram — the tank entry and exit incorporate PP wiper seals to minimize acid drag-out. The tank exterior is protected by an acid-resistant PP or FRP secondary containment bund with 110% of the primary tank volume per EPA SPCC requirements for acid storage.

PP Chemical Storage Tank

A PP chemical storage tank — also called a polypropylene chemical storage tank or PP acid storage tank — is a cylindrical or rectangular PP vessel designed for the bulk storage of corrosive chemicals at atmospheric pressure and ambient to moderate temperature. These tanks store fresh acid, prepared pickling solution, rinse water, and waste acid prior to neutralization, typically in volumes from 500 to 15,000 liters. Cylindrical vertical tanks with a flat or conical bottom are standard for bulk storage; rectangular tanks are used where floor space is constrained or where the tank serves as both storage and day-tank for a pickling line.

PP chemical storage tanks are fabricated from 8-20 mm PP sheet with external vertical and horizontal stiffener rings. The tank is closed with a bolted PP manway cover (400-600 mm diameter for tank access and inspection) and includes a vent connection sized per API 2000 for normal breathing and emergency venting. Level indication is via a PP sight tube with isolation valves or an external magnetic level gauge. For outdoor installation, UV-stabilized PP sheet with 2% carbon black prevents UV degradation of the tank shell over a 15-20 year service life. A bolted PP flange at the tank outlet connects to the chemical transfer pump suction line.

Pickling Tank Material Selection

Frequently Asked Questions

What is the difference between PP and FRP pickling tanks?

PP pickling tanks are fabricated by welding PP sheet and are the standard choice for hydrochloric and sulfuric acid pickling at temperatures up to 70°C. FRP pickling tanks use a fiberglass-reinforced vinyl ester laminate and are specified for higher temperatures (70-95°C), mixed nitric-hydrofluoric acid pickling, and applications requiring higher structural strength. PP provides equivalent corrosion resistance to FRP for HCl and H₂SO₄ at moderate temperatures and costs approximately 30-40% less than an equivalent FRP tank. FRP is required when nitric acid is present (PP is attacked by HNO₃ above 10% concentration) or when operating temperature exceeds PP’s continuous service rating.

What wall thickness does a pickling tank need?

Wall thickness is a function of tank depth, dimensions, and the specific gravity of the pickling solution (typically 1.1-1.2 for 10-18% HCl). The design criterion is a maximum deflection of L/200 (span/200) at the mid-span of the longest unsupported wall panel, with a 2× safety factor on the material’s allowable stress at the operating temperature. As a rule of thumb for PP tanks: 10 mm for depths up to 800 mm, 15 mm for 800-1,200 mm, 20 mm for 1,200-1,800 mm, and 25 mm for depths exceeding 1,800 mm. External PP rib stiffeners at 400-600 mm centers reduce the effective panel span and can decrease the required wall thickness by one step.

Can a single tank be used for multiple process steps?

Yes — multi-compartment PP tanks with internal PP divider walls allow pickling, rinsing, and passivation in a single tank unit. Each compartment is independently drained and has its own chemical feed and overflow connections. The divider walls are welded into the tank shell with the same material and joint quality as the external walls, providing a leak-tight barrier between compartments. This configuration reduces floor space by 30-40% and simplifies part transfer compared to individual tanks. The trade-off is that the tank volume is fixed per compartment — each compartment cannot be independently resized later.

Get a Pickling Tank Quote

XICHENG EP manufactures PP and FRP pickling tanks, electroplating tanks, etching tanks, and chemical storage tanks from 100 to 20,000 liters. Every tank is supplied with a hydrostatic test certificate, material certification, and a dimensional drawing showing all nozzle locations and stiffener positions. Contact our application engineers with your pickling chemistry, operating temperature, tank dimensions, and process flow diagram for a design proposal and quotation within 48 hours.

About XICHENG EP

XICHENG EP LTD is an industrial air pollution control equipment manufacturer with 16+ years of production experience, 2,600+ systems shipped, and installations in 60+ countries. We manufacture in China, with in‑house PP sheet extrusion, CNC cutting, hot‑gas welding, and FRP filament winding — every scrubber component from raw material to finished vessel is fabricated under one roof. No outsourced fabrication, no subcontractor delays.

Certifications and Compliance

• CE Marking — Machinery Directive 2006/42/EC, EMC Directive 2014/30/EU
• RoHS — 2011/65/EU compliant materials throughout
• ISO 9001:2015 — Quality management system
• ISO 14001:2015 — Environmental management system
• SGS material testing — PP sheet, FRP laminate, weld integrity verified
• Design basis per EU 2010/75/EU Industrial Emissions Directive
• Engineered to meet US EPA NESHAP and OSHA 1910.94

How to Order

1. Send your operating data: Gas flow rate (CFM or m³/hr), contaminant type and inlet concentration (ppm), required outlet limit per your permit, gas temperature, and available site footprint. Contact our engineering team
2. Receive your proposal: Within 48 hours — preliminary sizing, process flow diagram, budget price, and delivery timeline. No obligation
3. Review and approve: Once the proposal meets your requirements, we issue a formal quotation with detailed technical specifications
4. Drawing approval: P&ID, general arrangement, and electrical schematic for your sign‑off before fabrication begins
5. Manufacturing and testing: 6‑10 weeks fabrication. Pre‑shipment water‑tightness test, recirculation test, and control system checkout
6. Shipping and commissioning: Containerized sea freight or air freight worldwide. Remote commissioning support via video call included; optional on‑site supervision available

Global Shipping

We ship wet scrubber systems worldwide from our manufacturing facility in China. Regular containerized sea freight to ports in North America (Los Angeles, Houston, New York), Europe (Rotterdam, Hamburg, Antwerp), the Middle East (Jebel Ali, Dammam), Southeast Asia (Singapore, Port Klang), and Australia (Sydney, Melbourne). Air freight available for urgent deliveries and smaller systems. All equipment is crated, shrink‑wrapped, and container‑loaded with desiccant for ocean transit.

A laboratory fume hood — also called a chemical fume hood or lab exhaust hood — is a ventilated enclosure that captures and exhausts hazardous chemical vapors, acid fumes, solvent mists, and particulate generated during laboratory procedures, protecting personnel from inhalation exposure. The hood enclosure is fabricated from PP (polypropylene) or FRP (fiberglass reinforced plastic) for full corrosion resistance to acids, solvents, and oxidizing agents — unlike standard steel fume hoods that corrode internally within 2-3 years of perchloric or hydrochloric acid use. XICHENG EP manufactures PP and FRP laboratory fume hoods in ducted, ductless, walk-in, bench-top, and specialty chemical configurations, each designed to maintain a face velocity of 0.4-0.6 m/s (80-120 fpm) at the sash opening per ANSI/AIHA Z9.5 and ASHRAE 110 standards.

A PP fume hood with a constant-volume exhaust system handles 800-1,500 CFM at 0.5 inches w.g. static pressure for a standard 1.2 m (4 ft) width, using a backward-curved FRP exhaust fan mounted on the roof or in a dedicated fan room. The PP hood body is hot-gas welded from 8-10 mm PP sheet with an integral chemical-resistant work surface sloped to a front-mounted cup sink for spill containment. For perchloric acid or strong oxidizing applications, the hood interior includes a water wash-down spray system and all ductwork is vertical with no horizontal runs to prevent condensation pooling. All XICHENG EP fume hoods are factory-tested to ASHRAE 110 tracer gas containment standards before shipment.

Laboratory Fume Hood Range

PP Ducted Fume Hood

A PP ducted fume hood — also called a polypropylene fume hood or ducted PP fume hood — is a standard laboratory exhaust enclosure constructed from 8-10 mm PP sheet with a vertical sash (manual or motorized), an integral PP exhaust plenum, and a duct connection to an FRP centrifugal exhaust fan that discharges treated or untreated air outside the building. The ducted configuration provides permanent contaminant removal — all fumes exit the building through the ductwork — making it suitable for work with toxic gases, volatile solvents, and acid digestions where recirculation is prohibited by laboratory safety protocols.

Standard widths are 1.2 m, 1.5 m, and 1.8 m (4, 5, and 6 ft) with a working height of 800-900 mm and an overall height of 2,350 mm. The sash is 6 mm tempered glass or polycarbonate with a counterweight or chain-and-sprocket mechanism limiting maximum opening to 500 mm for operator protection. Interior features include a PP baffle system that directs airflow evenly across the work surface, a fluorescent or LED light fixture mounted outside the air stream behind a sealed PP window, and two 220V electrical outlets with GFCI protection. The exhaust duct connection is a 250-315 mm PP flange sized for an air velocity of 8-12 m/s in the duct to prevent condensation and droplet carryover.

Ductless Fume Hood

A ductless fume hood — also called a ductless laboratory fume hood or recirculating fume hood — filters contaminated air through an activated carbon and/or HEPA filter stack and returns the clean air to the laboratory, eliminating the need for external ductwork, roof penetrations, and an exhaust fan. The air passes through a pre-filter (captures particulate and mist), a main activated carbon bed (adsorbs organic vapors, acid gases, and ammonia), and optionally a HEPA H14 filter (captures 99.995% of particles at 0.3 μm) before discharging back into the room through a front or top grille.

Ductless hoods are specified for laboratories where installing ductwork is impractical — historical buildings, mobile labs, temporary facilities — or where the chemicals in use are well-characterized and the carbon filter’s saturation point can be predicted. A ductless PP fume hood with a bonded carbon filter (12-15 kg activated carbon, impregnated or virgin) provides 200-400 operating hours before filter replacement at typical laboratory usage rates. Filter life is monitored by a built-in gas sensor or a timer-based alarm. Ductless hoods are NOT suitable for perchloric acid, high-volume solvent work, or unknown chemical mixtures.

Walk-In Fume Hood

A walk-in fume hood — also called a walk-in fume hoods unit or walk-in laboratory hood — is a floor-standing PP enclosure with a full-height interior allowing personnel to enter and work inside the hood, typically used for large-scale laboratory apparatus, pilot-scale reactions, 55-gallon drum handling, and equipment that exceeds the working dimensions of a bench-top hood. The walk-in hood has a floor-level work surface (or a raised PP grating over a spill containment sump), full-height rear baffle, and either horizontal sliding doors or a vertical bifold door for equipment access.

Standard walk-in hoods are 1.2-1.8 m wide, 0.9-1.2 m deep, and 2.1-2.4 m interior height with an overall exterior height of 2.7-3.0 m. Exhaust volumes range from 2,000 to 5,000 CFM at 0.4-0.6 m/s face velocity with the doors fully open. The PP floor is reinforced to support 500 kg/m² for equipment loading. Walk-in hoods are deployed in pharmaceutical R&D, chemical pilot plants, university synthesis labs, and industrial quality control laboratories where the reaction apparatus — rotary evaporators, glass reactors, distillation columns — requires overhead clearance beyond a standard bench-top hood.

Chemical Fume Hood

A chemical fume hood — also called a chemical fume hoods workstation or chemical exhaust hood — is a ducted PP or FRP enclosure specifically designed for handling highly corrosive chemicals: concentrated hydrochloric, sulfuric, nitric, hydrofluoric, and perchloric acids. The PP hood body provides universal acid resistance, while the FRP exhaust duct and fan handle the acid-laden saturated exhaust stream without corrosion. Standard features include an acid-resistant PP work surface with a 12 mm thick epoxy or phenolic resin top, a cup sink with a PP drain valve, and service fixtures (water, gas, vacuum) with PP or PTFE valves and nozzles mounted on the front posts.

Perchloric acid hoods require a wash-down system: spray nozzles plumbed into the hood interior and exhaust duct to periodically flush perchlorate salt deposits that can accumulate and become shock-sensitive explosives upon drying. The exhaust system for a perchloric acid hood uses a dedicated FRP fan with a water spray in the duct and no horizontal duct runs, per NFPA 45 and manufacturer requirements. XICHENG EP chemical fume hoods are supplied with a chemical resistance matrix matching the hood material to the intended acids, solvents, and reagents specified by the end user.

Fume Hood Exhaust System

A fume hood exhaust system — also called a fume hood ventilation system or fume exhaust hood — is the complete air handling package that connects one or more fume hoods to the outdoors: the exhaust ductwork (PP or FRP, vertical riser), the FRP centrifugal exhaust fan (roof-mounted, belt-driven), and the make-up air system that replaces exhausted air to maintain laboratory pressurization. The exhaust system is engineered as a complete package because the fan static pressure, duct diameter, and hood face velocity are interdependent — under-sizing any component results in a face velocity below 0.4 m/s and compromised containment.

A multi-hood manifold system with 4-8 fume hoods on a common duct header reduces total fan count at the cost of reduced individual hood control: sash management is critical — closing one sash increases face velocity at the remaining open hoods. A dedicated fan per hood eliminates this cross-talk but adds capital cost. Variable air volume (VAV) systems use a sash position sensor to modulate a motorized damper and VFD-controlled fan to maintain constant face velocity regardless of sash position, reducing exhaust volume (and HVAC energy) by 40-60% when hoods are closed or at minimum sash opening. XICHENG EP engineers the complete exhaust system from hood face to fan discharge — duct sizing, fan selection, VAV controls, stack design — as a single integrated package.

Bench-Top Fume Hood

A bench-top fume hood — also called a bench top ducted fume hood or benchtop laboratory hood — is the standard laboratory fume hood configuration: a PP enclosure mounted on a PP or steel support stand at a working surface height of 850-900 mm (standard bench height), with the sash, work surface, baffle, and exhaust plenum integrated into the hood superstructure. The bench-top design fits into existing laboratory bench layouts and connects to the building exhaust duct via a roof riser. Standard accessories include a base cabinet for solvent storage (vented or unvented), service turrets for water, gas, and vacuum, and a digital airflow monitor with audible/visual low-flow alarm.

Bench-top PP hoods handle the widest range of laboratory chemistry — acid digestions, solvent extractions, sample preparations, titrations, and chemical synthesis — where the scale fits within a 1.2-1.8 m bench footprint. The PP hood interior is illuminated by a vapor-proof LED fixture providing 800-1,000 lux at the work surface, and the front airfoil at the sill directs incoming air smoothly across the work surface to eliminate dead zones and eddies where contaminants can accumulate. XICHENG EP bench-top fume hoods are available in PP (standard acid service), PPs (flame-retardant, UL 94 V-0 for solvent work), and FRP (high-temperature applications up to 95°C).

Fume Hood Material Selection

PP is the standard material for laboratory fume hoods handling common acids, alkalis, and solvents at ambient temperature. When additional requirements dictate a different material, the table below guides selection:

Frequently Asked Questions

What is the difference between ducted and ductless fume hoods?

A ducted fume hood exhausts contaminated air outside the building through a ductwork and fan system — all fumes are permanently removed. A ductless fume hood filters the air through activated carbon and returns it to the room. Ducted hoods are required for: unknown or mixed chemical use, high-volume solvent work, perchloric acid, and any application where filter breakthrough would create a personnel hazard. Ductless hoods are acceptable for well-characterized, low-toxicity chemical use in facilities where installing ductwork is not feasible. The trade-off is permanent installation cost (ducted) versus ongoing filter replacement cost (ductless).

What face velocity should a fume hood maintain?

ANSI/AIHA Z9.5 and SEFA 1 specify a face velocity of 0.4-0.6 m/s (80-120 fpm) at the maximum sash opening. Below 0.4 m/s, cross-drafts from personnel movement, door opening, or HVAC diffusers can disrupt containment. Above 0.6 m/s, turbulence at the sash opening can pull contaminants out of the hood. The target design point is 0.5 m/s (100 fpm) at a sash opening of 450-500 mm (18-20 inches). ASHRAE 110 tracer gas testing at the installed hood provides the definitive containment verification.

Can a single exhaust fan serve multiple fume hoods?

Yes — a manifold system with 2-8 hoods on a common duct header and a single FRP exhaust fan is standard in multi-hood laboratories. The design must account for diversity: not all hoods operate at full sash opening simultaneously. A VAV system with sash position sensors and motorized dampers at each hood maintains constant face velocity at each hood regardless of how many hoods are open. The alternative — one fan per hood — provides the best individual control and chemical isolation between hoods but at higher capital cost.

Get a Fume Hood Quote

XICHENG EP manufactures PP and FRP laboratory fume hoods in ducted, ductless, walk-in, bench-top, and specialty chemical configurations. Every hood is factory-tested to ASHRAE 110 and supplied with a material certificate, installation manual, and a 1-year warranty. Contact our application engineers with your laboratory layout, chemical inventory, and exhaust requirements for a hood selection and quotation within 48 hours.

About XICHENG EP

XICHENG EP LTD is an industrial air pollution control equipment manufacturer with 16+ years of production experience, 2,600+ systems shipped, and installations in 60+ countries. We manufacture in China, with in‑house PP sheet extrusion, CNC cutting, hot‑gas welding, and FRP filament winding — every scrubber component from raw material to finished vessel is fabricated under one roof. No outsourced fabrication, no subcontractor delays.

Certifications and Compliance

• CE Marking — Machinery Directive 2006/42/EC, EMC Directive 2014/30/EU
• RoHS — 2011/65/EU compliant materials throughout
• ISO 9001:2015 — Quality management system
• ISO 14001:2015 — Environmental management system
• SGS material testing — PP sheet, FRP laminate, weld integrity verified
• Design basis per EU 2010/75/EU Industrial Emissions Directive
• Engineered to meet US EPA NESHAP and OSHA 1910.94

How to Order

1. Send your operating data: Gas flow rate (CFM or m³/hr), contaminant type and inlet concentration (ppm), required outlet limit per your permit, gas temperature, and available site footprint. Contact our engineering team
2. Receive your proposal: Within 48 hours — preliminary sizing, process flow diagram, budget price, and delivery timeline. No obligation
3. Review and approve: Once the proposal meets your requirements, we issue a formal quotation with detailed technical specifications
4. Drawing approval: P&ID, general arrangement, and electrical schematic for your sign‑off before fabrication begins
5. Manufacturing and testing: 6‑10 weeks fabrication. Pre‑shipment water‑tightness test, recirculation test, and control system checkout
6. Shipping and commissioning: Containerized sea freight or air freight worldwide. Remote commissioning support via video call included; optional on‑site supervision available

Global Shipping

We ship wet scrubber systems worldwide from our manufacturing facility in China. Regular containerized sea freight to ports in North America (Los Angeles, Houston, New York), Europe (Rotterdam, Hamburg, Antwerp), the Middle East (Jebel Ali, Dammam), Southeast Asia (Singapore, Port Klang), and Australia (Sydney, Melbourne). Air freight available for urgent deliveries and smaller systems. All equipment is crated, shrink‑wrapped, and container‑loaded with desiccant for ocean transit.

A PP/FRP blower — also called a PP FRP centrifugal fan, fiberglass reinforced plastic blower, or FRP exhaust blower — is a corrosion-resistant industrial fan engineered to move air, chemical fumes, and corrosive gases in environments where metal fans fail. The housing and impeller are fabricated from FRP (fiberglass reinforced plastic) using chemical-grade unsaturated polyester or vinyl ester resin with E-glass fiber reinforcement, providing full resistance to acids, alkalis, solvents, and oxidizing atmospheres. XICHENG EP manufactures PP/FRP blowers in centrifugal (direct-driven and belt-driven), high-pressure, PP/FRP hybrid, axial flow, and roof exhaust configurations, covering air volumes from 500 to 120,000 m³/h at static pressures up to 5,000 Pa.

PP/FRP blowers eliminate the two failure modes that make metal fans unsuitable for corrosive exhaust: chemical attack on the impeller causing imbalance and catastrophic bearing failure, and housing perforation allowing toxic fugitive emissions. An FRP blower with a vinyl ester resin system operating in a hydrochloric acid or chlorine environment can achieve a service life of 12-15 years compared to 6-18 months for a coated steel fan in the same service. The lightweight FRP construction — approximately 40% the weight of equivalent 316L stainless steel — reduces structural support requirements and simplifies roof or mezzanine installation. All XICHENG EP FRP blowers are factory-balanced to ISO 1940 G6.3 and tested to 1.3× design speed before shipment.

FRP Blower Product Range

FRP Centrifugal Blower (Direct-Driven)

An FRP centrifugal blower — also called an FRP centrifugal fan or fiberglass centrifugal blower — is a radial-flow fan in which the impeller mounts directly on the motor shaft, eliminating belts, pulleys, and the maintenance associated with belt drives. The direct-driven configuration provides a compact footprint, zero slip losses, and precise speed control when paired with a VFD (variable frequency drive). The impeller uses backward-curved FRP blades for high efficiency (75-82% static) and non-overloading power characteristic — motor current decreases as the system resistance increases, preventing motor burnout if a damper closes downstream.

Direct-driven FRP blowers are the standard choice for laboratory fume hood exhaust, chemical storage tank vent headers, and scrubber discharge stacks where the air stream is saturated with corrosive moisture and reliability is paramount. The absence of belts means no belt dust in cleanroom exhaust and no belt replacement in hard-to-access rooftop installations. XICHENG EP produces direct-driven FRP centrifugal blowers from 0.75 kW to 55 kW motor power in standard impeller diameters from 250 mm to 1,200 mm with a maximum operating temperature of 80°C for vinyl ester resin systems.

FRP Belt Driven Exhaust Fan

A belt driven FRP exhaust fan — also called a belt driven FRP centrifugal fan or belt driven fiberglass fan — uses a belt and pulley transmission between the motor and impeller shaft, allowing the impeller speed to be adjusted independently of motor speed by changing pulley ratios. This flexibility makes belt-driven configurations ideal for applications where the exact system resistance is unknown at the time of specification — the pulley can be changed during commissioning to achieve the design operating point without replacing the motor. The motor is positioned outside the air stream on an MS-FRP (mild steel frame with FRP cladding) mounting base, isolating it from corrosive exhaust contact.

Belt-driven FRP blowers provide approximately 5-10% lower peak efficiency than direct-driven due to belt friction losses, but the ability to adjust airflow post-installation and the isolation of the motor from the corrosive air stream often outweigh this penalty in practice. Standard configuration includes a two-groove V-belt drive with a taper-lock bushing for positive pulley retention, and an FRP belt guard. Impeller diameters range from 315 mm to 1,600 mm with air volumes up to 120,000 m³/h, making belt-driven units the choice for large central exhaust systems, multi-branch scrubber networks, and applications where future airflow expansion is anticipated.

FRP High-Pressure Blower

An FRP high pressure blower — also called an FRP pressure blower or high pressure FRP fan — is a radial-tip or forward-curved impeller design engineered to develop static pressures of 2,500-5,000 Pa at moderate flow rates, overcoming the resistance of long duct runs, multiple branch take-offs, packed bed scrubbers, and activated carbon adsorbers connected in series. The impeller features narrower blade passages and a deeper blade profile than a standard centrifugal fan, trading some peak efficiency for the ability to push against high system resistance without stalling. The FRP housing is reinforced with external rib stiffeners to withstand the higher casing pressure without deflection.

High-pressure FRP blowers are specified when the combined pressure drop of the ductwork, control dampers, treatment equipment (scrubber or adsorber), and discharge stack exceeds what a standard centrifugal fan can deliver at a reasonable impeller diameter. A typical application is a central laboratory exhaust system serving 30-50 fume hoods through a manifold duct, where the fan static pressure requirement exceeds 3,000 Pa. The backward-curved or radial-tip impeller with FRP construction is inherently spark-resistant (no metal-to-metal contact possible), making these blowers suitable for solvent-laden exhaust where ATEX-rated construction is required at the motor and bearing assembly.

PP FRP Blower

A PP FRP blower — also called an FRP PP blower or PP FRP centrifugal fan — combines a polypropylene (PP) impeller with an FRP housing, leveraging the superior chemical resistance of PP at the gas-contact surface with the structural rigidity of FRP in the casing. PP provides better resistance than standard polyester FRP to specific chemicals: concentrated hydrochloric acid, wet chlorine, sodium hypochlorite, and oxidizing acids up to 80°C. However, PP alone lacks the structural stiffness to maintain tight impeller-to-inlet-cone clearance at larger diameters, which is where the FRP housing provides the necessary rigidity to prevent rubbing and maintain aerodynamic efficiency.

The hybrid construction is specified for applications where a standard polyester FRP blower would experience chemical attack — typically in chlor-alkali plants, bleach production, chromium plating exhaust, and mixed-acid fume extraction where the chemical cocktail includes oxidizing agents. The PP impeller is injection-molded or CNC-machined from PP sheet in diameters up to 800 mm, and the FRP housing uses a vinyl ester resin barrier layer at the gas-contact surface for additional chemical resistance. Jet Fibre and other manufacturers have validated this PP-FRP configuration across thousands of installations since the 1990s.

FRP Axial Fan

An FRP axial fan — also called an FRP axial exhaust fan or fiberglass axial fan — moves air parallel to the impeller shaft in a straight-through flow pattern, delivering high air volumes at low static pressures (typically 50-500 Pa). Unlike a centrifugal blower that turns the air stream 90 degrees through the impeller, an axial fan passes air axially through a cylindrical FRP casing with minimal direction change, achieving 80-88% static efficiency in its design range. The impeller uses aerofoil-section FRP blades with adjustable pitch angle, allowing the operating point to be tuned on-site by rotating each blade in its hub socket.

FRP axial flow fans are specified for general ventilation of corrosive atmospheres where the primary requirement is high air change rates rather than high pressure: chemical plant building ventilation, tank farm air circulation, wastewater treatment plant headspace exhaust, and large-open-area fume extraction where the duct resistance is minimal. An axial fan delivering 50,000 m³/h at 200 Pa consumes approximately 5.5 kW, compared to 11 kW for a centrifugal fan delivering the same flow against the same pressure — a 50% energy saving that compounds over the fan’s operating life. XICHENG EP produces FRP axial fans in diameters from 400 mm to 1,800 mm with direct-driven or belt-driven motor arrangements.

FRP Roof Exhaust Fan

An FRP roof exhaust fan — also called an FRP roof mounted exhaust fan or FRP rooftop exhaust fan — is a vertical-discharge centrifugal or axial fan packaged in a weatherproof FRP housing designed for direct mounting on a roof curb or steel platform. The vertical discharge configuration prevents re-entrainment of exhaust gases into building air intakes by discharging at high velocity (15-20 m/s nozzle velocity) at 3-5 meters above roof level. The weatherproof FRP dome or cowl protects the motor and bearings from rain, snow, and UV exposure, and a bird screen on the discharge prevents nesting inside the fan housing during idle periods.

Roof exhaust fans are the standard termination point for corrosive exhaust duct risers in chemical plants, pharmaceutical facilities, and laboratories, eliminating the need for a separate fan room and discharge stack. The vertical up-blast design with an FRP drain connection at the housing low point manages condensate from saturated exhaust streams, preventing the pooling of corrosive liquid inside the fan casing that would cause imbalance on restart. XICHENG EP FRP roof exhaust fans are available in centrifugal (higher pressure, for ducted systems) and axial (higher volume, for general ventilation) configurations from 400 mm to 1,400 mm fan diameter.

FRP Blower Material Selection & Resin Guide

FRP blower corrosion resistance is determined primarily by the resin system used in the laminate. Two resin chemistries cover the majority of industrial corrosive exhaust applications: unsaturated polyester (UPE) for general acid/alkali service and vinyl ester (VE) for stronger oxidizing agents and higher temperatures. The table below matches resin type to the exhaust stream chemistry it handles:

Frequently Asked Questions

What is the difference between an FRP blower and a PP blower?

An FRP blower uses fiberglass reinforced plastic for both the housing and impeller, providing high structural strength and a continuous service temperature up to 80°C (vinyl ester) or 95°C (novolac VE). A PP blower uses polypropylene for the impeller with either PP or FRP housing — it offers superior resistance to specific chemicals (wet chlorine, hypochlorite) but is limited to 70°C continuous. FRP blowers are preferred for larger installations (above 25,000 m³/h) where structural rigidity at large impeller diameters is critical. PP/FRP hybrid blowers combine the advantages of both materials for intermediate applications.

How is the impeller balanced?

All XICHENG EP FRP impellers are dynamically balanced to ISO 1940 G6.3 (balance quality grade), which limits the residual unbalance to 6.3 mm/s at operating speed. Balancing is performed on the assembled impeller after the FRP laminate has fully cured, using a two-plane dynamic balancing machine. The impeller is then over-sped to 1.3× design RPM as a proof test. For belt-driven units, the pulley is mounted before final balancing to account for the pulley mass distribution.

Can FRP blowers be used with variable frequency drives?

Yes — all direct-driven FRP blowers are VFD-compatible. The FRP impeller’s natural frequency is designed to be at least 1.3× above the maximum operating speed to avoid resonance through the VFD speed range. For belt-driven blowers, VFD control is also possible, but the minimum speed is limited by the belt drive’s ability to transmit torque at low RPM — typically a 2:1 turndown ratio (50-100% speed) for belt-driven compared to 5:1 (20-100%) for direct-driven.

What maintenance does an FRP blower require?

FRP blowers require significantly less maintenance than coated metal fans in corrosive service. Quarterly: inspect impeller for chemical attack or erosion at the blade tips, check inlet cone clearance (should be 2-4 mm depending on diameter), verify vibration levels at the bearing housing. Annually: replace bearing grease in pillow-block bearings (belt-driven), check belt tension and pulley alignment, inspect the FRP laminate for blistering or delamination at flange joints. FRP blowers do not require repainting, relining, or cathodic protection throughout their service life.

Get an FRP Blower Quote

XICHENG EP manufactures FRP blowers from 500 to 120,000 m³/h in centrifugal, high-pressure, PP/FRP hybrid, axial, and roof exhaust configurations. Every blower is supplied with a factory test report (flow, pressure, power, vibration), material certificates for the resin and glass reinforcement, and an ISO 1940 G6.3 balance certificate. Contact our application engineers with your airflow, static pressure, gas composition, and temperature requirements for a performance curve and quotation within 48 hours.

About XICHENG EP

XICHENG EP LTD is an industrial air pollution control equipment manufacturer with 16+ years of production experience, 2,600+ systems shipped, and installations in 60+ countries. We manufacture in China, with in‑house PP sheet extrusion, CNC cutting, hot‑gas welding, and FRP filament winding — every scrubber component from raw material to finished vessel is fabricated under one roof. No outsourced fabrication, no subcontractor delays.

Certifications and Compliance

• CE Marking — Machinery Directive 2006/42/EC, EMC Directive 2014/30/EU
• RoHS — 2011/65/EU compliant materials throughout
• ISO 9001:2015 — Quality management system
• ISO 14001:2015 — Environmental management system
• SGS material testing — PP sheet, FRP laminate, weld integrity verified
• Design basis per EU 2010/75/EU Industrial Emissions Directive
• Engineered to meet US EPA NESHAP and OSHA 1910.94

How to Order

1. Send your operating data: Gas flow rate (CFM or m³/hr), contaminant type and inlet concentration (ppm), required outlet limit per your permit, gas temperature, and available site footprint. Contact our engineering team
2. Receive your proposal: Within 48 hours — preliminary sizing, process flow diagram, budget price, and delivery timeline. No obligation
3. Review and approve: Once the proposal meets your requirements, we issue a formal quotation with detailed technical specifications
4. Drawing approval: P&ID, general arrangement, and electrical schematic for your sign‑off before fabrication begins
5. Manufacturing and testing: 6‑10 weeks fabrication. Pre‑shipment water‑tightness test, recirculation test, and control system checkout
6. Shipping and commissioning: Containerized sea freight or air freight worldwide. Remote commissioning support via video call included; optional on‑site supervision available

Global Shipping

We ship wet scrubber systems worldwide from our manufacturing facility in China. Regular containerized sea freight to ports in North America (Los Angeles, Houston, New York), Europe (Rotterdam, Hamburg, Antwerp), the Middle East (Jebel Ali, Dammam), Southeast Asia (Singapore, Port Klang), and Australia (Sydney, Melbourne). Air freight available for urgent deliveries and smaller systems. All equipment is crated, shrink‑wrapped, and container‑loaded with desiccant for ocean transit.

PP ductwork — also called polypropylene air duct or PP ventilation duct — is a corrosion-resistant thermoplastic piping system designed to transport corrosive exhaust gases, chemical fumes, and VOC-laden air in industrial and laboratory environments. Unlike galvanized steel or stainless steel ductwork that corrodes within months when exposed to acids, a PP duct system resists pH values from 1 to 14 across a temperature range of -5°C to 95°C, providing decades of maintenance-free service. XICHENG EP manufactures the full PP ductwork system — round duct, rectangular duct, flame-retardant PPs duct, injection-molded duct, fittings, dampers, and support accessories — all from virgin polypropylene copolymer (PP-C) or flame-retardant PPs sheet stock with hot-air and extrusion welding per DVS 2207 standards.

The core advantage of polypropylene ductwork is material compatibility at a fraction of the cost of alloy metals. PP sheet ductwork costs approximately 60-70% less than 316L stainless steel duct of equivalent diameter, weighs 80% less, and requires no protective coating or cathodic protection. For chemical laboratories, electroplating shops, semiconductor fabs, pharmaceutical plants, and municipal wastewater treatment facilities — anywhere acids, alkalis, solvents, or oxidizing agents are present in the exhaust air — PP duct is the standard specification. The smooth inner wall of 0.005 mm roughness delivers a friction factor of 0.002-0.003, reducing fan energy consumption by 15-20% compared to aged, corroded metal ductwork.

XICHENG EP produces PP ductwork in diameters from Φ63 mm to Φ3,000 mm using three manufacturing methods selected by size and application: injection molding for small-bore duct up to Φ500 mm providing uniform wall thickness and dimensional precision; sheet rolling and hot-air butt welding for medium and large diameters from Φ200 mm to Φ3,000 mm; and PPs flame-retardant compounding with V0-rated (UL 94) self-extinguishing properties for applications requiring fire resistance. Every duct section is factory-tested at 2× design static pressure before shipment.

PP Ductwork Product Range

PP Round Duct

PP round duct — also called polypropylene round duct or round ducting PP — is the standard geometry for industrial corrosion-resistant ventilation, manufactured by rolling PP sheet into a cylindrical form and butt-welding the longitudinal seam using hot-air or extrusion welding. Round ducting PP is preferred for exhaust gas transport because it delivers the lowest pressure drop per unit cross-sectional area, resists collapse under negative pressure without stiffeners, and self-drains condensate to the low point. XICHENG EP produces PP round duct from Φ200 mm to Φ3,000 mm internal diameter in standard lengths of 1.0 m, 1.5 m, 2.0 m, and 3.0 m, with wall thickness from 3 mm to 25 mm depending on diameter and design static pressure.

Round PP duct achieves 15-25% lower friction loss than rectangular duct of equivalent cross-sectional area, translating directly to smaller fan motors and lower operating cost over the 20-30 year service life of the system. For outdoor installations, UV-stabilized PP sheet with 2% carbon black loading prevents embrittlement from sunlight exposure. The duct sections connect via integral PP flanges with EPDM or FPM gaskets — no metal fasteners in the air stream — ensuring the corrosion-resistant envelope is continuous from hood to stack.

PPs Flame-Retardant Duct

PPs flame retardant duct — also called PPs ducting or flame retardant polypropylene duct — is an enhanced-grade PP ventilation duct manufactured from polypropylene sheet compounded with halogen-free flame retardant additives to achieve self-extinguishing performance. Standard PP duct carries a UL 94 HB (horizontal burn) classification; PPs duct achieves UL 94 V-0 — meaning the material stops burning within 10 seconds on a vertical specimen with no flaming drips. This rating makes PPs duct suitable for applications where fire propagation along the ventilation path is a safety concern: semiconductor cleanrooms, battery manufacturing exhaust, chemical storage ventilation, and any installation subject to NFPA or local fire code requirements for non-combustible ductwork.

PPs duct operates at continuous service temperatures up to 95°C — approximately 25°C higher than standard PP duct’s practical continuous limit — providing an additional thermal safety margin in processes where exothermic reactions or heated exhaust streams are present. PPs duct is manufactured in diameters from Φ63 mm (injection-molded) to Φ2,000 mm (sheet-rolled and welded), and is identifiable by its dark grey or black color from the flame-retardant compound. The material retains full chemical resistance to acids, alkalis, and solvents equivalent to standard PP, and is joined using the same hot-air and extrusion welding techniques with PPs-compatible welding rod.

PP Injection-Molded Duct

PP injection-molded duct — also called PP injection molded air duct or injection-molded PP duct — is a small-to-medium-bore ventilation pipe manufactured by injecting molten polypropylene copolymer into a precision steel mold under high pressure, producing a finished duct section in a single cycle with uniform wall thickness and smooth internal and external surfaces. Unlike sheet-rolled duct which has a longitudinal weld seam, injection-molded duct is seamless and dimensionally consistent section to section, making it the preferred choice for laboratory fume hood exhaust, cleanroom ventilation, and semiconductor tool exhaust where leak integrity and aesthetic finish matter.

Injection molding produces duct in diameters from Φ63 mm to Φ500 mm in standard 1.0 m and 2.0 m lengths, with integral socket ends for push-fit assembly that reduces installation labor by approximately 40% compared to flange-and-gasket connections. The process adds flame retardant and carbon black colorant directly into the melt stream for PPs V-0 and UV-stabilized variants. XICHENG EP operates in-house injection molding machines ranging from 500 to 3,000 tonnes clamping force, enabling production of duct sections and matching injection-molded fittings — elbows, tees, reducers, and couplings — from the same material batch for guaranteed dimensional compatibility.

PP Duct Fittings

Duct fittings PP — including elbows, tees, reducers, flanges, and couplings — are the connection components that make up a complete polypropylene plastic duct fittings network. A PP duct system is only as leak-tight as its joints, and injection-molded or fabricated PP fittings ensure material continuity at every change of direction, branch, and diameter transition. XICHENG EP supplies the full range of duct fittings PP in diameters matching the duct sections: injection-molded fittings for Φ63-500 mm and fabricated (welded from PP sheet) fittings for Φ200-3,000 mm.

PP elbows are available in standard angles of 30°, 45°, 60°, 75°, and 90° with a centerline radius of 1.0×, 1.5×, or 2.0× the duct diameter. PP tees are offered as equal (straight-through) or reducing (branch smaller than main) configurations; a 45° lateral tee is preferred over a 90° branch for lower pressure drop. PP reducers — concentric or eccentric — transition between duct diameters with a taper angle of 15-20° per side. PP flanges are fabricated as loose-ring (backup ring) or fixed-flange types with bolt patterns drilled to ANSI B16.5 150 lb or DIN PN10. PP couplings are short socket pieces for joining straight duct sections without flanges, typically used on small-bore injection-molded systems.

PP Duct Dampers & Valves

A PP duct damper — also called a plastic ventilation duct damper or PP motorized duct damper — is a flow regulation device installed within a polypropylene ventilation system to balance airflow, isolate branches, and prevent reverse flow in corrosive exhaust ductwork. Every multi-branch exhaust system requires dampers at each take-off point to balance the system to design airflow, and PP construction ensures the damper mechanism remains operable in corrosive service where metal damper blades and shafts would seize within months.

PP butterfly dampers use a circular PP disc rotating on a PP-coated or SS316 shaft within the duct cross-section, operated manually by a locking quadrant handle or automatically by an electric or pneumatic actuator. PP blast gates (guillotine dampers) provide positive shutoff for branch isolation with a sliding PP blade that retracts fully from the air stream when open. PP backdraft dampers use a gravity-closing PP flap or spring-assisted design to prevent reverse flow when a fan cycles off in a multi-fan common-header system. All damper types are available in diameters from Φ100 mm to Φ2,000 mm with flanged or slip-fit end connections, and can be supplied with EPDM or FPM (Viton) blade seals for tight shutoff to less than 1% leakage at design static pressure.

PP Duct Supports, Hangers & Accessories

A PP duct support — also called a duct support or duct supports bracket — is a structural component that suspends, guides, and anchors the ventilation ductwork from building steel or concrete. Because polypropylene has a coefficient of thermal expansion of 0.15 mm/m·K — approximately 10× that of carbon steel — the support design must accommodate thermal movement without over-stressing the duct wall or causing the system to buckle. A PP duct installation that ignores thermal expansion will develop leaks at flange joints or sag between supports within the first year of operation.

The standard support arrangement uses PP half-shell clamps (saddles) matching the duct outer diameter, clamped around the duct and bolted to a galvanized or SS316 steel hanger rod or trapeze bracket. The clamp distributes the load around 120-180° of the duct circumference, preventing point-load creep at the contact surface. Support spacing follows a deflection criterion of L/300 (span/300 maximum deflection) which for standard PP duct wall thicknesses translates to 2.0-3.0 m centers at ambient temperature, reduced by 30% for PPs duct at elevated temperature. For vertical risers, guide supports spaced at 4-6 m with a fixed anchor point at mid-riser allow thermal growth to dissipate in both directions. Additional accessories include cleanout caps, drain points with PP ball valves, test ports with threaded plugs, and flexible PP bellows expansion joints for systems exceeding 20 m straight length.

PP Duct Material Selection

Selecting between PP, PPs, and alternative duct materials depends on three factors: chemical composition of the exhaust stream, maximum continuous operating temperature, and applicable fire code requirements. Standard PP-C (polypropylene copolymer) duct covers the majority of laboratory and industrial corrosive exhaust applications at temperatures up to 70°C continuous. PPs flame-retardant duct adds V-0 self-extinguishing classification and extends the temperature ceiling to 95°C for applications such as semiconductor wet bench exhaust, battery formation room ventilation, and chemical storage tank vent headers where fire propagation risk must be mitigated.

For exhaust streams containing strong oxidizing acids (concentrated nitric, chromic, or sulfuric acid above 80%) or temperatures exceeding 95°C, PP is not recommended — FRP (fiberglass-reinforced plastic) or PVDF duct should be specified instead. For ambient-temperature applications with dilute acids and alkalis, PP delivers the lowest installed cost of any corrosion-resistant duct material. The table below summarizes the selection decision:

Frequently Asked Questions

What is the difference between PP and PPs duct?

The primary difference is flame retardancy. Standard PP duct is classified UL 94 HB (horizontal burn) and is suitable for general corrosive exhaust. PPs duct is classified UL 94 V-0 — it self-extinguishes within 10 seconds on a vertical specimen with no flaming drips — and is specified where local fire codes or NFPA standards require non-flame-propagating ductwork. PPs also tolerates a higher continuous temperature (95°C vs 70°C). The chemical resistance of both grades is equivalent.

How is PP ductwork joined in the field?

PP duct sections are joined by one of two methods: flanged connections using loose-ring PP flanges with EPDM or FPM gaskets (standard for duct ≥Φ200 mm), or socket push-fit connections with hot-air back-welding (standard for injection-molded duct ≤Φ500 mm). All welding follows DVS 2207 standards. No metal fasteners contact the air stream — the corrosion-resistant envelope is continuous.

What is the maximum length of a straight PP duct run before an expansion joint is needed?

The rule of thumb is 20 meters of straight length between expansion devices. PP expands at 0.15 mm/m·K, so a 20 m run with a 50°C temperature rise (from 20°C ambient to 70°C operating) will grow approximately 15 mm. A PP bellows expansion joint or a change-of-direction loop absorbs this movement. Runs shorter than 20 m can typically be managed by the natural flexibility of the duct at flange joints, provided hangers are not rigidly clamped.

Can PP duct be used outdoors?

Yes — PP duct is suitable for outdoor installation when manufactured from UV-stabilized PP sheet containing 2% carbon black loading. Without UV stabilization, standard natural PP will embrittle and lose impact strength after 3-5 years of direct sun exposure. UV-stabilized PP duct carries the same chemical resistance and mechanical ratings as indoor-grade material.

Get a PP Ductwork Quote

XICHENG EP manufactures the complete PP ductwork system — duct sections, fittings, dampers, and support hardware — in diameters from Φ63 mm to Φ3,000 mm. Every system is engineered to your duct layout drawing and shipped with material test certificates and DVS-qualified weld procedure specifications. Contact our applications engineering team with your duct isometric or P&ID for a material take-off and quotation — typical turnaround is 48 hours for standard diameters.

About XICHENG EP

XICHENG EP LTD is an industrial air pollution control equipment manufacturer with 16+ years of production experience, 2,600+ systems shipped, and installations in 60+ countries. We manufacture in China, with in‑house PP sheet extrusion, CNC cutting, hot‑gas welding, and FRP filament winding — every scrubber component from raw material to finished vessel is fabricated under one roof. No outsourced fabrication, no subcontractor delays.

Certifications and Compliance

• CE Marking — Machinery Directive 2006/42/EC, EMC Directive 2014/30/EU
• RoHS — 2011/65/EU compliant materials throughout
• ISO 9001:2015 — Quality management system
• ISO 14001:2015 — Environmental management system
• SGS material testing — PP sheet, FRP laminate, weld integrity verified
• Design basis per EU 2010/75/EU Industrial Emissions Directive
• Engineered to meet US EPA NESHAP and OSHA 1910.94

How to Order

1. Send your operating data: Gas flow rate (CFM or m³/hr), contaminant type and inlet concentration (ppm), required outlet limit per your permit, gas temperature, and available site footprint. Contact our engineering team
2. Receive your proposal: Within 48 hours — preliminary sizing, process flow diagram, budget price, and delivery timeline. No obligation
3. Review and approve: Once the proposal meets your requirements, we issue a formal quotation with detailed technical specifications
4. Drawing approval: P&ID, general arrangement, and electrical schematic for your sign‑off before fabrication begins
5. Manufacturing and testing: 6‑10 weeks fabrication. Pre‑shipment water‑tightness test, recirculation test, and control system checkout
6. Shipping and commissioning: Containerized sea freight or air freight worldwide. Remote commissioning support via video call included; optional on‑site supervision available

Global Shipping

We ship wet scrubber systems worldwide from our manufacturing facility in China. Regular containerized sea freight to ports in North America (Los Angeles, Houston, New York), Europe (Rotterdam, Hamburg, Antwerp), the Middle East (Jebel Ali, Dammam), Southeast Asia (Singapore, Port Klang), and Australia (Sydney, Melbourne). Air freight available for urgent deliveries and smaller systems. All equipment is crated, shrink‑wrapped, and container‑loaded with desiccant for ocean transit.

Activated Carbon Adsorber Types

Fixed-Bed Carbon Adsorber

A fixed‑bed carbon adsorber — also called a carbon adsorbers unit or fixed bed adsorber — is the standard industrial configuration: a horizontal or vertical vessel containing a stationary bed of activated carbon through which contaminated air passes. The carbon bed, typically 0.3‑1.0 m deep, provides 800‑1,200 m² of adsorption surface per gram of carbon. Gas velocity through the bed is 0.1‑0.5 m/s to maintain sufficient residence time of 0.1‑0.5 seconds.

The EPA Carbon Adsorbers chapter identifies fixed‑bed systems as the most widely used configuration for controlling VOC and HAP emissions from storage tanks, process vents, and loading operations at refineries, chemical plants, and pulp and paper mills. Carbon adsorption capacity is typically 10‑40% of the carbon weight for common VOCs. Two vessels in a lead‑lag configuration allow continuous operation — one vessel online while the other undergoes carbon changeout. Replacement frequency ranges from monthly for heavily loaded streams to annually for polishing applications.

Carbon Adsorption Tower

A carbon adsorption tower — also called an activated carbon tower or activated carbon adsorption tower — is a vertical cylindrical vessel filled with activated carbon media, designed for higher air volumes than a flat‑bed adsorber. The contaminated gas enters at the bottom or top and passes vertically through the carbon bed, with typical bed depths of 0.5‑1.5 m.

The activated carbon tower handles benzene, toluene, xylene, ketones, and chlorinated solvents at concentrations from 10 to 500 ppm. Gas velocity through the tower is 0.2‑0.5 m/s with residence times of 0.3‑1.0 seconds. The cylindrical design minimizes dead zones and ensures uniform gas distribution compared to rectangular flat‑bed configurations. Tower diameters range from 500 mm for lab‑scale to 3,000 mm for industrial applications up to 30,000 CFM. A pre‑filter section upstream captures particulate and mist that would blind the carbon pores.

Activated Carbon Filter Box

An activated carbon filter box — also called an active carbon filter box or carbon air box filter — is a compact rectangular enclosure housing one or more carbon filter trays, designed for inline duct mounting or standalone operation for flow rates from 200 to 5,000 CFM. The active carbon filter box uses V‑bank or flat‑tray configurations to maximize carbon bed surface area within a limited housing depth. Each tray holds 50‑150 mm of granular activated carbon between perforated PP or stainless steel screens.

Multiple trays in series (typically 2‑4) provide staged adsorption. The rectangular housing with gasketed access doors allows tray changeout without removing the unit from the ductwork. Construction is PP for corrosive exhaust or powder‑coated carbon steel for general VOC applications. Carbon filter boxes serve as point‑of‑use odor control for pump stations, lab exhaust, solvent storage areas, and small process vents.

Impregnated Carbon Adsorber

An impregnated carbon adsorber — also called an impregnated activated carbon system or impregnated carbon unit — uses activated carbon chemically treated with an acid, base, or oxidizing agent to enable chemisorption — a chemical reaction that permanently fixes the pollutant within the carbon pore structure. Standard virgin activated carbon relies on physical adsorption alone and performs poorly on low‑molecular‑weight gases like NH₃, H₂S, and formaldehyde.

Acid‑impregnated carbon (H₃PO₄ or H₂SO₄, 5‑15% loading) removes ammonia via 2NH₃ + H₂SO₄ → (NH₄)₂SO₄. Caustic‑impregnated (NaOH or KOH) targets H₂S, SO₂, and mercaptans. Oxidizing‑impregnated (KMnO₄) handles formaldehyde and ethylene oxide. Impregnated carbon achieves 90‑99% removal at inlet concentrations below 50 ppm. It is not thermally regenerable — the chemical is consumed. Service life is 3‑12 months depending on gas loading, with media replacement cost of $3‑8 per kg.

Carbon Polishing Unit

A carbon polishing unit — also called an activated carbon polishing system or carbon polishing filter — is a secondary carbon adsorber installed downstream of a primary treatment system (wet scrubber, biofilter, or thermal oxidizer) to remove residual VOCs, H₂S, and odor compounds to below detection thresholds. The polishing unit handles gas that has already been treated to 90‑95% — the remaining 5‑10% is low‑concentration but still odorous or above permit limits.

Polishing beds are typically 0.3‑0.6 m deep with gas velocities of 0.2‑0.4 m/s, providing 0.2‑0.5 seconds of residence time. Because the inlet loading is low, carbon service life is 12‑24 months — significantly longer than a primary carbon adsorber. Dry scrubber polishing stages are commonly deployed following wet scrubbing or biofiltration. A carbon polishing unit is the most cost‑effective way to achieve zero‑odor discharge when a wet scrubber alone leaves detectable odor at the property line.

Portable Carbon Adsorber

A portable carbon adsorber — also called a mobile carbon adsorber or trailer mounted carbon adsorption system — is a self‑contained, skid‑mounted or trailer‑mounted carbon adsorption system designed for temporary deployment, rental service, or pilot testing. Common configurations include vapor‑phase adsorbers with pre‑filled carbon canisters and liquid‑phase systems with multiple adsorber vessels and manifold piping.

Portable adsorbers typically handle 200‑2,000 CFM for vapor‑phase and 10‑100 GPM for liquid‑phase applications. The carbon is pre‑loaded and changeout is handled by the rental provider. Three primary use cases: emergency spill response with 24‑hour dispatch, temporary treatment during permanent system installation or maintenance, and pilot testing to collect design data before committing to a permanent installation.

Materials and Construction

The adsorber vessel material depends on the gas stream corrosivity and operating temperature:

The carbon media itself is selected based on the target contaminant: virgin activated carbon (coconut shell or coal‑based, 800‑1,200 m²/g surface area) for general VOC adsorption; acid‑impregnated carbon for ammonia and amines; caustic‑impregnated for H₂S and mercaptans; and oxidizing‑impregnated (KMnO₄) for formaldehyde and ethylene oxide. Media is available in pelletized (4 mm diameter, lower pressure drop) or granular (2‑3 mm, higher surface area) forms. Pelletized carbon is standard for vapor‑phase applications; granular is used where bed depth is limited and maximum surface area per unit volume is required.

How to Select a Carbon Adsorber

Four inputs determine the right carbon adsorber configuration:

1. Contaminant type: VOC → virgin carbon. NH₃/amines → acid‑impregnated. H₂S/mercaptans → caustic‑impregnated. Mixed → layered or multi‑stage
2. Inlet concentration: Below 100 ppm → any configuration works. 100‑500 ppm → fixed‑bed or tower with deeper bed. Above 500 ppm → consider wet scrubbing upstream, carbon polishing downstream
3. Flow rate: 200‑2,000 CFM → filter box or portable. 2,000‑10,000 CFM → fixed‑bed or tower. Above 10,000 CFM → multiple vessels in parallel or adsorption tower
4. Space and access: Limited footprint → tower (vertical). Frequent media change → filter box (tray access). Temporary → portable rental unit

Frequently Asked Questions

How does an activated carbon adsorber work?

An activated carbon adsorber passes contaminated air through a bed of activated carbon with 800‑1,200 m² of internal surface area per gram. Gas molecules physically adsorb onto the carbon pore surfaces via van der Waals forces. For chemically reactive gases like NH₃ and H₂S, impregnated carbon provides chemisorption — a chemical reaction that permanently fixes the pollutant within the pore structure. Carbon adsorbers achieve 90‑99% removal at inlet concentrations below 100 ppm for VOCs and below 50 ppm for reactive gases. Spent carbon is periodically replaced and either thermally reactivated or disposed of.

How often does activated carbon need to be replaced?

Carbon service life depends on the inlet concentration and the carbon’s adsorption capacity. For a VOC stream at 50 ppm with a 0.5 m carbon bed, typical service life is 6‑12 months before breakthrough occurs. For a polishing unit treating already‑scrubbed air with residual concentrations below 5 ppm, service life extends to 12‑24 months. Impregnated carbon has a shorter life than virgin carbon because the chemical impregnant is consumed — 3‑12 months depending on gas loading. Breakthrough is detected by outlet gas monitoring or periodic carbon sampling for laboratory analysis of remaining adsorption capacity.

Can activated carbon be regenerated?

Virgin activated carbon saturated with VOCs can be thermally reactivated — the adsorbed organics are driven off at 800‑900°C in a controlled‑atmosphere furnace, restoring 90‑95% of the original adsorption capacity. Impregnated carbon is not regenerable because the chemical impregnant is consumed in the reaction. Spent impregnated carbon is disposed of by incineration or landfill per local hazardous waste regulations. Carbon reactivation is typically performed off‑site by the carbon supplier; on‑site regeneration is economical only for very large systems above 50,000 CFM with continuous operation.

Get a Carbon Adsorber Proposal

We custom‑engineer every activated carbon adsorber system to your gas flow rate, contaminant profile, outlet limits, and site constraints — in PP, carbon steel, or stainless steel construction. Contact our engineering team with your exhaust data and we will provide a preliminary sizing, budget price, and system specification within 48 hours.

About XICHENG EP

XICHENG EP LTD is an industrial air pollution control equipment manufacturer with 16+ years of production experience, 2,600+ systems shipped, and installations in 60+ countries. We manufacture in China, with in‑house PP sheet extrusion, CNC cutting, hot‑gas welding, and FRP filament winding — every scrubber component from raw material to finished vessel is fabricated under one roof. No outsourced fabrication, no subcontractor delays.

Certifications and Compliance

• CE Marking — Machinery Directive 2006/42/EC, EMC Directive 2014/30/EU
• RoHS — 2011/65/EU compliant materials throughout
• ISO 9001:2015 — Quality management system
• ISO 14001:2015 — Environmental management system
• SGS material testing — PP sheet, FRP laminate, weld integrity verified
• Design basis per EU 2010/75/EU Industrial Emissions Directive
• Engineered to meet US EPA NESHAP and OSHA 1910.94

How to Order

1. Send your operating data: Gas flow rate (CFM or m³/hr), contaminant type and inlet concentration (ppm), required outlet limit per your permit, gas temperature, and available site footprint. Contact our engineering team
2. Receive your proposal: Within 48 hours — preliminary sizing, process flow diagram, budget price, and delivery timeline. No obligation
3. Review and approve: Once the proposal meets your requirements, we issue a formal quotation with detailed technical specifications
4. Drawing approval: P&ID, general arrangement, and electrical schematic for your sign‑off before fabrication begins
5. Manufacturing and testing: 6‑10 weeks fabrication. Pre‑shipment water‑tightness test, recirculation test, and control system checkout
6. Shipping and commissioning: Containerized sea freight or air freight worldwide. Remote commissioning support via video call included; optional on‑site supervision available

Global Shipping

We ship wet scrubber systems worldwide from our manufacturing facility in China. Regular containerized sea freight to ports in North America (Los Angeles, Houston, New York), Europe (Rotterdam, Hamburg, Antwerp), the Middle East (Jebel Ali, Dammam), Southeast Asia (Singapore, Port Klang), and Australia (Sydney, Melbourne). Air freight available for urgent deliveries and smaller systems. All equipment is crated, shrink‑wrapped, and container‑loaded with desiccant for ocean transit.

Installed System Examples

The photographs below show XICHENG wet scrubber equipment and typical exhaust-system arrangements. The exact tower count, access structure, fan, duct routing and footprint are project-specific.

Request an Engineering Proposal