A weir-type PVC-U diaphragm valve with integral ANSI/DIN/JIS flanges — stem-free, packing-free shutoff and throttling for corrosive and particulate-laden process lines.
Ningbo Baodi Plastic Valve Co., Ltd. traces its origins back to 1979, with its predecessors being Zhenhai Chemical Valve Factory and Beilun Plastic Valve Factory. The company is one of the earliest Flanged PVC Diaphragm Valves Manufacturers and Custom Flanged PVC Diaphragm Valves Factory in China to design and produce industrial plastic valves and receive acceptance from the Ministry of Chemical Industry. In 1979, the company manufactured its first plastic diaphragm valve, which passed the technical appraisal of the Ministry of Chemical Industry in 1983. In 1992, the company invented the one-piece flange ball valve, a structural design that has since become the most widely used plastic valve product in chemical-related industries. The development history of the company and its predecessors also represents an important chapter in the application of plastic valves in China's industrial production.
In 2006, the company expanded its product line to cover industrial plastic pipes and fittings, becoming one of the first domestic enterprises to apply CPVC material in the production of industrial-grade piping valves. Over more than 40 years since its establishment, the company has designed and manufactured various plastic valves for the most demanding industries. It has served tens of thousands of enterprises both domestically and internationally, exporting to more than 60 countries, and has consistently remained a leading manufacturer of industrial thermoplastic valves and piping systems. Our professional service and stable quality have always been well received and recognized by customers.
Baodi ranks among the global leaders in the number of product categories, capable of fully covering industrial plastic pipe and valve requirements. The company has obtained ISO 9001, ISO 14001, and ISO 45001 system certifications, as well as the national special equipment pressure piping component manufacturing license. It is recognized as a National High-Tech Enterprise and a Ningbo City Specialized and Sophisticated Enterprise. Baodi is a principal drafter of the national standard for plastic diaphragm valves and the chemical industry standards for plastic diaphragm valves, plastic ball valves, and plastic check valves.
Design Idea
2D Drawing
3D Modeling
Mold Fabrication
Prototype Testing
Full-scale production
Flanged PVC diaphragm valves use a flexible elastomer diaphragm, drawn down by a compressor and stem onto a weir or seat inside the PVC-U body, to open, throttle, or shut off flow. Because the diaphragm itself isolates the process fluid from the bonnet and operating mechanism, there is no stem packing gland exposed to the media — removing a common leak path found on ball and gate valves and making the design well suited to abrasive slurries, fibrous liquids, and corrosive process streams.
Integral flanges molded to ANSI, DIN, or JIS patterns let the valve bolt directly into flanged PVC-U pipe runs, tanks, and manifolds without adapters. The bolted, gasketed connection suits process lines that are already built around flanged plastic piping, and the diaphragm's compressor mechanism gives the operator tactile feedback on seating force, useful for both bubble-tight shutoff and fine flow throttling in one valve.
Wherever the process fluid carries solids, fibers, or crystals, a diaphragm's smooth, unobstructed flow path resists clogging in a way a ball valve's cavity cannot.
The PVC-U body resists a broad range of chemicals; the diaphragm elastomer is selected separately to match the specific fluid in contact with it.
| Diaphragm Material | Temperature Range | Typical Strengths | Common Use |
| EPDM | 0°C to 60°C | Good resistance to water, dilute acids, and alkalis | General water treatment and utility service |
| FPM (Viton) | 0°C to 60°C | Better resistance to oils, fuels, and some solvents | Chemical lines carrying oils or aggressive solvents |
| PTFE-Faced EPDM | 0°C to 60°C | Broadest chemical resistance with a non-stick PTFE contact surface | Aggressive or fouling-prone chemical processes |
| Item | Description |
| Valve Type | Flanged weir-type PVC-U diaphragm valve |
| Body Material | PVC-U |
| Diaphragm Material | EPDM, FPM (Viton), or PTFE-faced EPDM |
| Bonnet Material | PVC-U or glass-reinforced polypropylene |
| Size Range | DN15 – DN100 (1/2 inch – 4 inch) |
| End Connection | Integral flange to ANSI, DIN, or JIS pattern |
| Working Pressure | Up to 150 psi (10 bar) at 20°C, rating decreases with temperature |
| Working Temperature | 0°C to 60°C, diaphragm dependent |
| Sealing Performance | Bubble-tight shutoff, suitable for throttling duty |
| Operation | Handwheel standard; actuator mounting available |
| Flow Path | Weir-type body with raised seat for reduced diaphragm travel |
Both provide flanged shutoff, but a diaphragm valve's flow path handles solids and fibers differently than a ball valve's rotating cavity.
| Factor | Flanged Diaphragm Valve | Flanged Ball Valve |
| Handling Solids/Fibers | Smooth weir path resists clogging and fiber wrap | Ball cavity can trap solids and fibers |
| Throttling Ability | Good, diaphragm position gives proportional flow control | Limited, ball valves are primarily on/off |
| Stem Sealing | No stem packing exposed to process fluid | Stem seal exposed to process fluid |
| Cavitation/Erosion | Weir shape reduces turbulence at partial opening | Higher turbulence possible at partial opening |
| Maintenance Item | Diaphragm replacement, a wear item by design | Seat and seal wear, generally longer service intervals |
| Best Use | Slurries, fibrous or particulate-laden fluids | Clean liquids and gases needing tight shutoff |
A compressor driven by the handwheel presses the diaphragm down onto the weir seat to throttle or shut off flow.
Inspection confirms both body pressure integrity and diaphragm sealing performance before packing.
A bonnet-mounted actuator interface allows the handwheel to be replaced with pneumatic or electric operation for automated duty.
| Operation Type | Best Suited For | Key Characteristics |
| Handwheel | Manual throttling and local shutoff | Lowest cost, direct tactile control of diaphragm position |
| Pneumatic Actuator | Automated slurry or dosing lines with air supply available | Fast open/close or proportional control with a positioner |
| Electric Actuator | Remote-controlled or monitored process valves | Integrates with control systems and remote monitoring |
Payment: T/T (bank transfer), L/C, and PayPal are accepted, with flexible terms for repeat orders. A deposit is typically required to confirm production.
Shipping: Sea freight (FCL/LCL) for bulk orders, air freight for urgent shipments, and courier for samples. Valves ship in wooden crates with flange faces protected by cover plates.
Delivery: Shipment from the nearest available port or airport, with FOB, CIF, or EXW terms available on request.
Each valve is covered under a standard warranty against manufacturing defects in material and workmanship, generally valid for 12 months from the shipment date.
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Overview A raised-seat body geometry that reduce
Overview A diaphragm valve sized and specified f
Overview Handwheel-operated diaphragm shutoff fo
Overview Compressed-air operation for automated
Overview The full diaphragm valve range, from bo
Share your flange standard, size, and process fluid details, and get a diaphragm material recommendation.
Start your cooperation journey with Baodi
Contact
baodivalve@bdsjfm.com
+86-574-86817753
+86-574-86812190
After-Hours Hotline：
+86-18395898313
NO.42 Yongjiang Road, Beilun,Ningbo city, Zhejiang province,P.R.China
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