UPVC diaphragm valves — also known as PVC diaphragm valves — are the economical workhorse for ambient-temperature water and mild chemical service: industrial and RO water, weak acids and alkalis, salt solutions, and seawater. We supply them in true union, flanged, and pneumatic configurations, built from virgin UPVC (unplasticized PVC) and easy to install with standard solvent cement.
A diaphragm valve isolates the media behind a flexible diaphragm, so no stem packing contacts the fluid and there is no crevice to trap or contaminate it — a clean, low-maintenance choice for water treatment and light chemical lines.
UPVC (PVC) chemical compatibility
UPVC — the rigid, unplasticized form of PVC — is rated to about 55 °C and suits ambient-temperature water and mildly corrosive media.
Suitable: ambient industrial water and reverse-osmosis (RO) water; weak acids and alkalis; general inorganic salt solutions; seawater and high-salinity media.
Not recommended: strong oxidising acids (high-concentration sulfuric or nitric); aromatic and chlorinated solvents (benzene, toluene, acetone); hot, strong alkalis.
As with all thermoplastics, the allowable pressure falls as temperature rises. For a specific medium and temperature, send us the details or see our chemical resistance reference.
Why our UPVC / PVC diaphragm valves
- Excellent value. UPVC is the economical first choice for ambient-temperature and mildly corrosive service.
- Easy to install. Rigid PVC bonds with standard solvent cement, so no special fusion-welding tools are needed — fast, low-cost installation.
- Double-diaphragm design, low compression set. The diaphragm assembly seals tightly and the body distributes closing pressure evenly, lowering closing torque and keeping flow regulation stable.
- No dead space, no packing wear. The diaphragm seals the media completely — nothing stagnates and nothing wears against the stem.
- Customisable. Bonnet, compressor, stem, bolts, and diaphragm can all be specified, including 304 or 316 stainless steel stems and fasteners. We use virgin branded resin and supply factory-direct.
Diaphragm material options
| Diaphragm | Best suited to |
|---|---|
| EPDM + PTFE | Alkalis, alcohols, acetone, ambient water |
| FKM + PTFE | Oils, aromatics, mild acids |
| EPDM + FEP (F46) | High-pressure gas, pure water, anti-permeation duty |
Configurations
True union UPVC diaphragm valve
Manually operated, DN15–DN50 (1/2″–2″), with union end connectors that let you lift the valve out for service without cutting pipe — ideal for water-treatment skids and tight installations.
Flanged UPVC diaphragm valve
DN15–DN150 (1/2″–6″) to ANSI, DIN, or JIS flange standards. The bolted flange gives greater strength against pipe stress and vibration, and is the standard choice for larger-bore water mains and permanent lines.
Pneumatic UPVC diaphragm valve
DN15–DN150 with a corrosion-resistant all-plastic actuator in double-acting or spring-return (fail-safe) action. An adjustable closing-stroke stop protects the diaphragm, and the valve accepts solenoid valve, limit switch, positioner, and air filter regulator for automated water-treatment lines.
Specifications
| Body material | UPVC (unplasticized PVC), virgin branded resin |
| Size range | DN15–DN150 (1/2″–6″); true union DN15–DN50 |
| Pressure rating | PN10 (derates with temperature) |
| Max temperature | ~55 °C |
| Body design | Weir type |
| Diaphragm | EPDM + PTFE / FKM + PTFE / EPDM + FEP |
| Connection | True union / flanged (ANSI / DIN / JIS) |
| Operation | Manual / pneumatic (double-acting or spring-return) |
| Stem & bolts | 304 or 316 stainless steel option |
| No. | Parts | Materials |
|---|---|---|
| 1 | Gauge Cover | PC |
| 2 | Stud Nut | Steel, Stainless Steel |
| 3 | Hand Wheel | ABS, PPG |
| 4 | Bonnet | UPVC |
| 5 | Sleeve | Cast Iron with Nickel Plating, Copper Alloy |
| 6 | Board | Plastic-coated Steel, Stainless Steel |
| 7 | Stud Bolt & Nut | Steel, Stainless Steel |
| 8 | Stem | Steel, Stainless Steel, Copper Alloy |
| 9 | Body | UPVC |
| 10 | Compressor | UPVC |
| 11 | Cushion | EPDM, FPM |
| 12 | Diaphragm | EPDM, FPM, PVDF, FEP, PFA, PTFE |
Flanged Diaphragm Valve — Dimensions (mm) 法兰隔膜阀 产品尺寸表
| DN | D1 (mm) | D (mm) | L (mm) | h (mm) | n | φ (mm) | |||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| HG/DIN | JIS | ANSI | HG/DIN | JIS | ANSI | HG | DIN | JIS | ANSI | HG/DIN | JIS | ANSI | HG/DIN | JIS | ANSI | ||
| 15 | 95 | 95 | 95 | 65 | 70 | 60 | 125 | 130 | 110 | 110/108 | 14 | 4 | 4 | 4 | 14 | 15 | 16 |
| 20 | 105 | 100 | 100 | 75 | 75 | 70 | 135 | 150 | 120 | 120/150 | 16 | 4 | 4 | 4 | 14 | 15 | 16 |
| 25 | 115 | 125 | 125 | 85 | 90 | 79 | 145 | 160 | 130 | 130/150 | 16 | 4 | 4 | 4 | 14 | 15 | 16 |
| 32 | 135 | 135 | 135 | 100 | – | 89 | 160 | 180 | 142* | 160 | 16 | 4 | 4 | 4 | 18 | 19 | 16 |
| 40 | 145 | 145 | 145 | 110 | 105 | 98 | 180 | 200 | 180 | 180/176 | 16 | 4 | 4 | 4 | 18 | 19 | 16 |
| 50 | 160 | 160 | 160 | 125 | 120 | 121 | 210 | 230 | 210 | 210/202 | 18 | 4 | 8 | 4 | 18 | 19 | 19 |
| 65 | 180 | 180 | 180 | 145 | 140 | 140 | 250 | 290* | 250 | 250 | 22 | 4 | 8 | 4 | 18 | 19 | 19 |
| 80 | 195 | 195 | 195 | 160 | 150 | 152 | 300 | 310 | 280 | 280/264* | 25 | 8 | 8 | 4 | 18 | 19 | 19 |
| 100 | 215 | 220 | 220 | 180 | 175 | 190 | 350 | 350 | 340 | 340/329* | 25 | 8 | 8 | 8 | 18 | 19 | 19 |
| 125 | 255 | 255 | 255 | 210 | 210 | 216 | 400 | 400 | 410 | 410 | 30 | 8 | 8 | 8 | 18 | 22 | 22 |
| 150 | 280 | 280 | 280 | 240 | 240 | 241 | 460 | 480 | 480 | 480 | 30 | 8 | 8 | 8 | 22 | 23 | 22 |
| 200 | 340 | 340 | 340 | 295 | 290 | 298 | 575 | 600* | 570 | 570 | 38 | 8 | 12 | 8 | 22 | 23 | 22 |
| 250 | 395 | 395 | 395 | 350 | 355 | 362 | 685 | 730* | 680 | 680 | 38 | 12 | 12 | 12 | 25 | 25 | 26 |
| 300 | 480 | 480 | 480 | 400 | 400 | 432 | 790 | – | – | – | 40 | 12 | 16 | 12 | 22 | 25 | 26 |
D1 = flange OD; D = bolt-circle dia. (PCD); L = face-to-face length; h = flange thickness; n = number of bolt holes; φ = bolt-hole dia. Values given per flange standard (HG / DIN / JIS / ANSI). * non-standard — confirm the bolt pattern when ordering. A “/” in the ANSI column shows two reference values. DN300 L is listed for HG only. DN32 D (JIS) was not legible in the source image — please confirm from your drawing.
Pneumatic Diaphragm Valve — Dimensions (mm) 气动隔膜阀 产品尺寸表
| DN (mm) | 15 | 20 | 25 | 32 | 40 | 50 | 65 | 80 | 100# | |
|---|---|---|---|---|---|---|---|---|---|---|
| H | 157 | 160 | 163 | 165 | 260 | 265 | 380 | 395 | 441 | |
| L | HG | 125 | 135 | 145 | 160 | 180 | 210 | 250 | 300 | 350 |
| DIN | 130 | 150 | 160 | 180 | 200 | 230 | 290* | 310 | 350 | |
| JIS | 110 | 120 | 130 | 142* | 180 | 210 | 250 | 280 | 340 | |
| ANSI | 110/108 | 120/150 | 130/150 | 160 | 180/176 | 210/202 | 250 | 280/264* | 340/329* | |
H = overall height; L = face-to-face length per flange standard (HG / DIN / JIS / ANSI). # DN100 uses a plastic pneumatic actuator — media pressure must not exceed 0.6 MPa. * non-standard dimension. A “/” in the ANSI row shows two reference face-to-face values. For more sizes, see the flanged diaphragm valve page.
Pneumatic Actuator — Parameters 执行器参数表
| DN (mm) | 15 | 20 | 25 | 32 | 40 | 50 | 65 | 80 | 100 | |
|---|---|---|---|---|---|---|---|---|---|---|
| Operating pressure (MPa) | 0.4–0.6 | |||||||||
| Air consumptionNL per open & close | Double acting0.4 MPa air | 1.25 | 1.25 | 1.29 | 1.29 | 4.35 | 4.8 | 23.8 | 24.5 | 26.1 |
| Air to open / NC0.5 MPa air | 0.55 | 0.55 | 0.59 | 0.59 | 2.08 | 2.37 | 9.2 | 9.8 | 11.6 | |
| Air to close / NO0.4 MPa air | 0.75 | 0.75 | 0.79 | 0.79 | 2.63 | 2.82 | 8.4 | 8.7 | 12 | |
| Air supply bore | RC 1/4 | |||||||||
Air consumption is per open/close cycle (NL). NC = single-acting, spring-return, normally closed (air opens). NO = single-acting, spring-return, normally open (air closes).
Typical applications
UPVC (PVC) diaphragm valves are specified for ambient water and light chemical duty: industrial water treatment (filtration and purification systems), seawater desalination and reverse-osmosis plants, and ambient-temperature dilution and transfer of mild chemicals. To weigh UPVC against the other thermoplastics, see our plastic valve material selection guide.
Why buy UPVC / PVC diaphragm valves from Huiya
Our UPVC / PVC diaphragm valves are built for ambient water and mild chemical service, supplied factory-direct — so you get the right configuration, competitive pricing, and a fast reply with no trading-company markup.
- ✅ Factory-direct — our own 2,000+ m² plant in Zhejiang, no middleman
- ✅ 100% virgin branded resin, fully traceable; produced at an ISO 9001-certified facility; material test reports on request
- ✅ Low MOQ — 20 pieces; samples available; OEM / custom welcome
- ✅ Fast lead time — about 7 days standard, 14 days custom
- ✅ 12-month warranty
Or explore our full range of UPVC / PVC valves.
Get a factory-direct quote
Send us your medium, its concentration and temperature, and the line size. Our engineers confirm the right body material, seat and valve type — and reply within 24 hours.
Frequently asked questions
Is a UPVC diaphragm valve the same as a PVC diaphragm valve?
In practice, yes. UPVC stands for unplasticized PVC — the rigid form of PVC used for pressure pipe and valves — so “UPVC diaphragm valve” and “PVC diaphragm valve” refer to the same rigid PVC valve. The flexible, plasticized PVC used in hoses is a different material and is not used here.
What is a UPVC (PVC) diaphragm valve used for?
UPVC diaphragm valves are used for ambient-temperature water and mild chemical service — industrial and RO water, weak acids and alkalis, salt solutions, and seawater — in water treatment, desalination, and light chemical dosing.
What temperature and pressure can a UPVC diaphragm valve handle?
The UPVC body is rated to about 55 °C and PN10 at ambient temperature, with the allowable pressure falling as temperature rises. For hotter service, CPVC (to ~90 °C) is the better choice.
What chemicals is UPVC suitable for?
UPVC handles weak acids and alkalis, general inorganic salt solutions, and seawater well. It is not recommended for strong oxidising acids (high-concentration sulfuric or nitric), aromatic and chlorinated solvents, or hot strong alkalis.
Is UPVC good for seawater and reverse-osmosis (RO) systems?
Yes. UPVC resists seawater and high-salinity media and is widely used in desalination and RO plants, where its corrosion resistance and low cost are a strong combination.
UPVC or CPVC — which should I choose?
Choose UPVC for ambient-temperature water and mild chemicals where cost is the priority. Choose CPVC when the line runs hot or carries hot acids, as it keeps its strength to about 90 °C.
Can a UPVC diaphragm valve be pneumatically actuated?
Yes. We offer a pneumatic UPVC diaphragm valve with a corrosion-resistant all-plastic actuator in double-acting or spring-return action, with optional solenoid valve, limit switch, positioner, and air filter regulator.
What sizes, pressure rating, and minimum order apply?
Sizes run from DN15 to DN150 (1/2″–6″), rated PN10, with a minimum order of 20 pieces and OEM/custom configurations available. Send us your media and conditions for a quotation.