A compact threaded-end diaphragm valve for small-bore branch, sample, and instrument lines — stem-free sealing in a screw-together connection.
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 Threaded Industrial Diaphragm Valves Manufacturers and Custom Threaded Industrial 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
Threaded industrial diaphragm valves use BSP or NPT threaded end connections instead of flanges, molded into a compact PVC-U, PP, or PVDF body that houses the same flexible diaphragm and weir seat arrangement found on larger flanged valves. Threaded ends suit smaller pipe sizes where flanges would add unnecessary bulk and cost, and where the valve connects into threaded metal or plastic fittings already common on instrument, sample, and small process branch lines.
Even at reduced size, the diaphragm isolates the process fluid from the bonnet and stem, so there is no packing gland in contact with the media — an advantage carried over from the larger flanged range. This keeps threaded diaphragm valves suitable for small-bore lines carrying particulate-laden, corrosive, or fouling fluids where a small ball or globe valve's cavity or seat geometry would be more prone to clogging or leaking over time.
Small-bore branch and instrument connections often use threaded fittings, and a threaded diaphragm valve keeps the same clog-resistant sealing in that size range.
Body material is chosen for chemical and temperature compatibility, while the diaphragm elastomer is matched separately to the specific process fluid.
| Body Material | Temperature Range | Typical Strengths | Common Use |
| PVC-U | 0°C to 60°C | Broad chemical resistance, economical | General small-bore water and chemical service |
| PP | 0°C to 90°C | Good solvent resistance, lightweight | Elevated-temperature dosing and sample lines |
| PVDF | -20°C to 99°C | Superior resistance to strong oxidizers and halogens | Aggressive or high-purity small-bore chemical lines |
| Item | Description |
| Valve Type | Threaded weir-type industrial diaphragm valve |
| Body Material | PVC-U, PP, or PVDF |
| Diaphragm Material | EPDM, FPM (Viton), or PTFE-faced EPDM |
| Bonnet Material | PVC-U, PP, or glass-reinforced polypropylene |
| Size Range | DN8 – DN50 (1/4 inch – 2 inch) |
| End Connection | Threaded (BSP or NPT) |
| Working Pressure | Up to 150 psi (10 bar) at 20°C, rating decreases with temperature |
| Working Temperature | 0°C to 90°C, body and diaphragm dependent |
| Sealing Performance | Bubble-tight shutoff, suitable for throttling duty |
| Operation | Handwheel standard |
| Flow Path | Weir-type body with raised seat for reduced diaphragm travel |
Both offer a compact threaded connection; the choice depends on whether the fluid carries solids or needs throttling control.
| Factor | Threaded Diaphragm Valve | Threaded Ball Valve |
| Handling Solids/Fibers | Smooth weir path resists clogging | Ball cavity can trap solids and fibers |
| Throttling Ability | Good, proportional flow control | Limited, primarily on/off duty |
| Stem Sealing | No stem packing exposed to process fluid | Stem seal exposed to process fluid |
| Body Length | Slightly longer for the same nominal size | More compact for the same nominal size |
| Cost | Somewhat higher for equivalent size | Generally lower cost |
| Best Use | Particulate-laden or fouling small-bore fluids | Clean liquids and gases needing tight shutoff |
A compact bonnet and compressor mechanism presses the diaphragm onto the weir seat within a threaded-end body.
Thread fit and diaphragm sealing performance are both checked before packing, given the tighter tolerances at small bore sizes.
Small sizes are typically handwheel-operated; mid-range sizes within the family can accept a compact actuator.
| Operation Type | Best Suited For | Key Characteristics |
| Handwheel | Local sample, instrument, and small branch line control | Lowest cost, direct tactile control of diaphragm position |
| Compact Pneumatic Actuator | Automated small-bore dosing or sample points | Fits DN25–DN50 with a compact actuator interface |
| Compact Electric Actuator | Remote-controlled small-bore isolation | Wired for control panel integration |
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 express courier for samples. Valves are cartoned and palletized for container loading.
Delivery: Shipment from the nearest available port or airport, with door-to-door, FOB, CIF, or EXW terms 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.
Overview The full diaphragm valve range, from bo
Overview Built for corrosive and high-purity flu
Overview CPVC shutoff engineered for hot water a
Overview Automatic backflow prevention in corros
Overview A dual-connection PVC valve with both t
Overview Handwheel-operated diaphragm shutoff fo
Overview Compressed-air operation for automated
Overview Lift-type checks designed for upward fl
Overview A reinforced body and bonnet for demand
Share your thread standard, size, and process fluid details, and get a body and 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
Custom Threaded Industrial Diaphragm Valves Manufacturers
