Compressed-air-driven diaphragm shutoff and throttling on a PVC-U, CPVC, PP, or PVDF body — automated, clog-resistant flow control for process lines with air supply available.
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 Pneumatic Plastic Diaphragm Valves Manufacturers and Custom Pneumatic Plastic 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
Pneumatic plastic diaphragm valves combine a corrosion-resistant PVC-U, CPVC, PP, or PVDF diaphragm valve body with a pneumatic actuator that drives the compressor up and down using compressed air instead of a handwheel. Because the diaphragm's proportional sealing behavior lends itself to positioning, not just full open or closed, the actuator can be paired with a positioner for modulating flow control, in addition to simple automated on/off duty.
The valve body keeps the same weir-type flow path and stem-free diaphragm sealing used across the manual range, so solids-handling ability is unchanged when automation is added. Solenoid valves, limit switch boxes, and positioners can be fitted to the actuator for remote signaling, position feedback, or proportional throttling control, making this configuration a common choice for automated slurry, dosing, and chemical process lines controlled from a PLC or DCS.
Compressed air is already available in most process plants, making pneumatic actuation a fast, cost-effective way to automate diaphragm valve throttling and shutoff.
The valve body and diaphragm materials are selected for chemical service, while the actuator housing is chosen for the ambient environment.
| Component | Material Options | Selection Basis | Notes |
| Valve Body | PVC-U, CPVC, PP, PVDF | Matched to the process fluid and temperature | Wetted parts unchanged from manual valve |
| Diaphragm | EPDM, FPM (Viton), PTFE-faced EPDM | Matched to the specific process fluid | Selected independently of body material |
| Actuator Housing | Anodized aluminum or glass-reinforced nylon (PA66) | Ambient environment, indoor/outdoor duty | Powder-coated aluminum for corrosive atmospheres |
| Positioner (optional) | Pneumatic or electro-pneumatic | Modulating flow control applications | Converts a control signal into proportional diaphragm position |
| Item | Description |
| Valve Type | Pneumatically actuated weir-type diaphragm valve |
| Body Material | PVC-U, CPVC, PP, or PVDF |
| Diaphragm Material | EPDM, FPM (Viton), or PTFE-faced EPDM |
| Size Range | DN15 – DN100 (1/2 inch – 4 inch) |
| End Connection | Socket, threaded, or flanged |
| Working Pressure (valve) | Up to 150 psi (10 bar) at 20°C, material dependent |
| Working Temperature | 0°C to 95°C, body and diaphragm dependent |
| Actuator Type | Pneumatic diaphragm or piston actuator |
| Air Supply | Clean, dry compressed air, typically 40–90 psi (3–6 bar) |
| Control Modes | On/off or modulating with a positioner |
| Optional Accessories | Solenoid valve, limit switch box, positioner, air filter/regulator |
Both automate quarter-turn or linear shutoff; the choice depends on whether the fluid needs solids handling and proportional control.
| Factor | Pneumatic Diaphragm Valve | Pneumatic Ball Valve |
| Handling Solids/Fibers | Smooth weir path resists clogging and fiber wrap | Ball cavity can trap solids and fibers |
| Throttling Ability | Strong, well suited to modulating control with a positioner | Limited, primarily suited to on/off duty |
| Actuator Motion | Linear compressor stroke | 90° rotary stroke |
| Stem Sealing | No stem packing exposed to process fluid | Stem seal exposed to process fluid |
| Cycle Speed | Moderate, proportional to stroke length | Very fast, typically under a few seconds |
| Best Use | Automated slurry, dosing, and throttling duty | Automated clean-fluid on/off shutoff |
A pneumatic actuator replaces the handwheel, driving the compressor stroke that presses the diaphragm onto the weir seat.
Inspection covers both the valve body and the actuator's air-driven stroke before the two are shipped as a matched assembly.
Actuator size and spring rating are matched to the valve's diaphragm area and the available air supply pressure.
| Control Type | Best Suited For | Key Characteristics |
| On/Off Pneumatic Actuator | Simple automated shutoff points | Direct-acting stroke driven by supply air pressure |
| Pneumatic Actuator with Positioner | Modulating flow control loops | Proportional diaphragm positioning driven by an analog control signal |
| Fail-Safe Spring Return | Applications requiring a defined position on air loss | Spring drives the diaphragm open or closed if air supply is interrupted |
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 of matched valve-actuator assemblies.
Shipping: Sea freight (FCL/LCL) for bulk orders, air freight for time-sensitive automation projects, and courier for samples. Assemblies ship pre-mounted and tested in wooden crates.
Delivery: Shipment from the nearest available port or airport, with door-to-door, FOB, CIF, or EXW terms on request.
Each assembly is covered under a standard warranty against manufacturing defects in material and workmanship, generally valid for 12 months from the shipment date, covering both valve and actuator.
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Overview A CPVC flow path for diaphragm valve se
Share your valve material, size, control requirements, and air supply pressure, and get an actuator sizing 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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