Plastic Butterfly Valves

Industrial Plastic Butterfly Valves

Plastic butterfly valves provide quarter-turn flow control and isolation for corrosive fluid handling, high-purity water systems, and general chemical distribution. Designed as lightweight, corrosion-resistant alternatives to metallic valves, these units eliminate electrochemical pitting, reduce structural pipe stress, and operate with lower operating torque.

Standard technical boundaries for the product range:

Size Range: DN50 to DN300 (2 inches to 12 inches)
Pressure Rating: PN10 / 150 PSI at 20 degrees C (68 degrees F), derating appropriately with elevated working temperatures
Body and Disc Materials: UPVC, CPVC, PPH, PVDF
Seat / Seal Options: EPDM, FKM (Viton), PTFE-backed EPDM
Actuation Interfaces: ISO 5211 direct-mount pad for pneumatic and electric actuators, manual lever, or worm gear operators

Product Range

PVC (UPVC) Butterfly Valve

Working Temperature: 0 degrees C to 60 degrees C (32 degrees F to 140 degrees F)
Nominal Pressure: PN10 (150 PSI at 20 degrees C)
Key Strengths: High mechanical strength, smooth interior walls preventing scale buildup, cost-effective for general acid/alkali media and water treatment.
Limitations: Not suitable for aromatic hydrocarbons, chlorinated solvents, or temperatures exceeding 60 degrees C.

CPVC Butterfly Valve

Working Temperature: 0 degrees C to 95 degrees C (32 degrees F to 203 degrees F)
Nominal Pressure: PN10 (150 PSI at 20 degrees C); pressure derating applied above 40 degrees C
Key Strengths: Higher chlorination content provides elevated heat deflection temperatures and improved resistance to hot corrosive acids, sodium hypochlorite, and industrial wastewater.
Limitations: Vulnerable to strong polar solvents like ketones and esters.

PPH (Polypropylene Homopolymer) Butterfly Valve

Working Temperature: -10 degrees C to 90 degrees C (14 degrees F to 194 degrees F)
Nominal Pressure: PN10 (150 PSI at 20 degrees C)
Key Strengths: Excellent impact strength, high chemical resistance against strong alkalis and pickling acids, low thermal conductivity.
Limitations: Higher thermal expansion coefficient; degrades when exposed to concentrated oxidizing acids (e.g., nitric acid).

PVDF Butterfly Valve

Working Temperature: -20 degrees C to 120 degrees C (-4 degrees F to 248 degrees F)
Nominal Pressure: PN10 (150 PSI at 20 degrees C)
Key Strengths: Exceptional purity (low extractables), superior chemical inertness against halogenated compounds, strong acids, ozone, and UV exposure. Flame retardant (UL94 V-0).
Limitations: Higher material cost; heavier mass relative to UPVC.

Plastic Wafer Butterfly Valve

Body Style: Compact wafer design installed between ANSI B16.5 Class 150, DIN PN10/16, or JIS 10K flanges using through-bolts.
Primary Advantage: Minimal face-to-face dimensions reduce piping footprint and installation weight. Integral alignment holes assist centering during installation.

Plastic Lug Butterfly Valve

Body Style: Features threaded metal inserts molded directly into the outer lug points.
Primary Advantage: Allows dead-end service, enabling downstream piping disassembly while maintaining pressure isolation upstream. Compatible with ANSI Class 150 bolt patterns.

Key Product Characteristics

Monolithic/Modular Disc Construction

Hydrodynamically contoured disc minimizes pressure drop (Delta P) and turbulence, optimizing flow coefficient (Cv) values.

Non-Wetted Stem Design

The stem is completely isolated from process media by full-body liner seals and dual O-ring stem packings (EPDM or FKM), preventing shaft corrosion and media contamination.

Integral ISO 5211 Mounting Pad

Standardized top-flange dimensions permit direct mounting of electric or pneumatic actuators without external brackets or drive couplings, eliminating backlash.

Full-Boot Seat Liner

The elastomeric seat extends over the valve face, acting as an integrated flange gasket. Separate flange gaskets are not required during installation.

Precision Notch Plate

Heavy-duty lever handles incorporate a multi-position notch plate with lockable positioning for throttle control.

Material & Media Compatibility

Selecting the correct body, seal, and stem combination depends on fluid chemical concentration, operational temperature, and mechanical stress:

UPVC
Compatible Media: Cold acids, alkalis, saline solutions, water treatment chemicals
Incompatible Media: Esters, ketones, aromatic hydrocarbons, boiling water
Max Temp: 60 degrees C

CPVC
Compatible Media: Hot acids, sodium hypochlorite, chlorinated water, caustic soda
Incompatible Media: Ketones, ethers, concentrated nitric acid
Max Temp: 95 degrees C

PPH
Compatible Media: Caustic soda, pickling acids, organic acids, industrial effluents
Incompatible Media: Concentrated nitric acid, chlorine gas, ozone
Max Temp: 90 degrees C

PVDF
Compatible Media: Nitric acid, sulfuric acid, wet chlorine, high-purity DI water, ozone
Incompatible Media: Fuming sulfuric acid, strong polar amines
Max Temp: 120 degrees C

EPDM Seal
Compatible Media: Water, dilute acids, alkalis, alcohols, glycol
Incompatible Media: Mineral oils, petroleum solvents, aromatic hydrocarbons
Max Temp: 120 degrees C

FKM Seal
Compatible Media: Strong acids, petroleum oils, halogenated hydrocarbons
Incompatible Media: Hot water/steam, low molecular weight organic acids
Max Temp: 150 degrees C

Connection & Configuration Options

Flange Compatibility

Dual/multi-standard bolt holes accommodate ANSI B16.5 Class 150, EN 1092-1 PN10/PN16, and JIS B2220 10K patterns.

Manual Operators

Lever Handle: Spring-loaded trigger locking lever with 10-degree index intervals (sizes DN50 to DN150).
Worm Gear Operator: Weatherproof cast aluminum or plastic enclosure with position indicator and handwheel for high torque requirements (sizes DN200 to DN300).

Automated Actuation

Pneumatic Actuators: Double-acting or spring-return (fail-safe) configurations with NAMUR solenoid valve interfaces and limit switch boxes.
Electric Actuators: On/Off or modulating (4-20mA / 0-10V control input) enclosures rated IP67/IP68, equipped with manual override handwheels.

Key Specifications

Size Range	DN50 to DN300 (2 inches to 12 inches)
Pressure Rating	1.0 MPa / PN10 / 150 PSI at 20 degrees C
Flange Hole Patterns	ANSI B16.5 Class 150, DIN PN10, JIS 10K
Body / Disc Materials	UPVC, CPVC, PPH, PVDF
Seat / Liner Materials	EPDM, FKM, PTFE-wrapped EPDM
Stem / Shaft Material	Stainless Steel 304, 316, or Carbon Steel (fully encapsulated / non-wetted)
Leakage Class	ANSI/FCI 70-2 Class VI (Zero Bubble-Tight Leakage)
Actuator Mounting	ISO 5211 Standard (F05 / F07 / F10 / F12)
Testing Standard	ISO 5208, EN 12266-1

How to Select the Right Plastic Butterfly Valve

Verify Chemical & Temperature Boundaries

Determine the maximum process temperature and media concentration. Cross-reference chemical resistance tables for disc, seat liner, and body materials. Apply temperature derating curves to ensure the operating pressure does not exceed PN10 thresholds at elevated temperatures.

Determine Connection Style

Select a Wafer style for inline flow isolation where space and weight are primary constraints. Select a Lug style if end-of-line service or downstream system maintenance without draining upstream lines is required.

Calculate Required Cv and Line Velocity

Evaluate differential pressure (Delta P) across the disc. Ensure fluid velocity remains below 3 m/s for liquids to prevent cavitational erosion on the disc leading edge.

Evaluate Sealing Torque & Actuation Requirements

Verify available air supply pressure (for pneumatic actuation) or voltage tolerances (for electric actuation). Confirm the actuator output torque includes a minimum 25% safety margin above the valve break-torque rating under max operating pressure.

Applications

Industrial Wastewater & Sewage Treatment: Resists aggressive sludge, flocculants, acid neutralizing agents, and sodium hydroxide streams.

Chemical Processing Facilities: Manages aggressive acid transfer lines, brine recirculation, and chemical dosing systems without metal leaching.

Desalination & Marine Systems: Prevents galvanic and chloride pitting corrosion associated with seawater intake and reverse osmosis (RO) filtration skids.

Semiconductor & High-Purity Water: PVDF body configurations maintain ultra-low extractables in Deionized (DI) water lines and microelectronics process chemical distribution.

Aquaculture & Commercial Swimming Pools: Provides long-term resistance to salt water and high chlorine concentration lines.

Quality & Inspection

Production testing and quality verification processes include:

Raw Material Verification: Fourier-Transform Infrared Spectroscopy (FTIR) testing and melt flow index (MFI) verification ensure 100% virgin resin consumption without unapproved regrind content.

Dimensional Checks: CMM inspection of stem bores, disc dimensions, and body seal grooves to maintain tolerance fits.

Hydrostatic Shell Testing: Every valve body undergoes shell testing at 1.5x PN rating (1.5 MPa / 225 PSI) for 60 seconds per ISO 5208.

Seat Leakage Testing: 100% pneumatic seat closure testing performed at 1.1x nominal working pressure (1.1 MPa) to verify ANSI Class VI zero-leakage performance.

Torque & Cycle Testing: Random sampling batch testing through 10,000 continuous open/close cycles under full pressure differential to verify seat wear rates.

OEM / ODM & Customization

Customization capabilities for system integrators and distributor brand requirements include:

Custom Labeling & Brand Molding: Private label laser engraving on nameplates, customized handle colors, and integrated body logo inserts.

Material Modifications: Custom compounding including UV-stabilized resins for outdoor installations or glass-filled polymers for high structural rigidity.

Specialized Shaft Materials: Shaft upgrades to Titanium, Hastelloy C276, or Duplex Stainless Steel for high-stress or extreme chemical exposure.

Pre-Assembled Valve Automation Packages: Factory mounting, calibration, and wiring of client-specified electric actuators, positioners, limit switches, and solenoid valves.

Packaging Solutions: Individual skin-pack retail packaging, customized inner boxes, or export-grade crate packing labeled with customer SKU numbers and barcoding.

FAQ

Q: How do operating temperatures affect the working pressure of plastic butterfly valves?

A: Plastic mechanical strength decreases as temperature increases. While rated for 10 bar (150 PSI) at 20 degrees C, operating pressure must be derated at higher temperatures. For instance, a CPVC valve operating at 80 degrees C retains roughly 30% to 40% of its room-temperature working pressure rating.

Q: Can plastic butterfly valves be used for throttling service?

A: Yes. Lever-operated units feature notch plates allowing manual throttling in 10-degree increments. For automated throttling, electric or pneumatic actuators with 4-20mA positioning controllers are used. However, operating the valve below 20 degrees open for prolonged periods can induce localized cavitation wear on the disc edge.

Q: Is a separate flange gasket required when installing these valves?

A: No. The elastomeric seat liner (EPDM or FKM) wraps around the outer face of the valve body, providing a built-in sealing face against mating pipe flanges. Installing additional flat gaskets can cause uneven sealing pressure and stem binding.

Q: What causes high operating torque during field installation?

A: High operating torque is typically caused by over-tightening flange bolts, misalignment of adjacent pipe flanges, or using piping with inadequate inner diameters (e.g., Schedule 80 pipe without proper chamfering) which restricts full disc movement.

Q: What is the primary difference between Wafer and Lug style plastic butterfly valves?

A: Wafer valves are clamped between two flanges using long tie-rods through the entire assembly. Lug valves feature embedded threaded metal inserts around the body, allowing downstream piping to be disconnected while leaving the valve attached to upstream pressurized lines.

Q: How do non-wetted stems protect system purity?

A: The valve stem is fully isolated inside the body and disc, sealed by dual shaft O-rings. Process media contacts only the plastic body, disc, and elastomeric seat liner. This prevents metal ions from leaching into high-purity media and protects the metal shaft from chemical attack.

Request a Quote

To receive a detailed commercial quotation, technical datasheets, or CAD/STEP models, supply the following operational parameters to our engineering team:
Valve Size & Connection Style: (e.g., DN100 / 4 inch Wafer)
Body & Disc Material: (UPVC, CPVC, PPH, or PVDF)
Seat & O-Ring Material: (EPDM or FKM)
Media Details: (Chemical name, concentration percentage, working temperature)
Operating Pressure & Flow Rate: (bar/PSI and Cv requirements)
Actuation Type: (Manual lever, gear operator, pneumatic double-acting/spring-return, or electric)
Estimated Order Volume & Delivery Schedule

We're well-known as one of the leading plastic butterfly valves manufacturers in China. If you're going to buy high quality plastic butterfly valves in stock, welcome to get quotation and free sample from our factory. Also, customized service is available.