bellows seal pneumatic single seat control valve

Body: WCB, SS316,SS316L
Ends: Flange, SW
Seat: 17-4PH Stainless Steel ASTM A564Gr630
Size: 1/2″ – 12″ (15mm – 300mm)
End connections:
ASME B16.34 class 150-600
Actuator: pneumatic actuator, electric actuator

    Category: Control valve


    The bellows seal single-seat control valve utilizes a top-guided unbalanced structure, renowned for its robustness, heavy-duty capability, S-type flow channel, minimal pressure drop, high flow coefficient, broad adjustability, and precise flow characteristics. The incorporation of a double sealing mechanism with bellows and packing at the bonnet ensures complete prevention of media leakage. This control valve is ideal for regulating flow and pressure of hazardous or valuable substances.

    The press-in type seat design of the cage resolves issues associated with challenging disassembly and high leakage in traditional thread screw-in seat designs, enhancing the valve’s longevity. With a flow-to-open configuration, the medium flow aligns with the valve’s opening direction, enabling precise control over small openings and minimal distortion in flow characteristics. Tailored cages equipped with noise reduction and anti-cavitation features can be provided to suit diverse operational requirements.

    bellows seal pneumatic single seat control valve


    Valve material

    • Valve body material: WCB,WCC,WC6, CF8, CF8M, CF3M
    • Valve cover material: WCB, CF8, CF8M, CF3M
    • Valve trim: SS316+STL
    • Packing: PTFE, graphite
    • Nominal diameter: 1/2“-10“ DN15-DN250
    • Nominal pressure: ANSI150, 300, 600  JIS 16, 20, 30, 40K  PN1.6, 4.0, 6.4, 10MPa
    • Body type: straight-through, angle

    Bonnet type:

    • standard,
    • heat dissipation,
    • bellows,
    • jacket insulation


    • flange FF, RF, RJ, TG,
    • MFM
    • Welding
    • SW

    Flow characteristics:

    • linear
    • Equal percentage

    Leakage level: 

    • hard seal (ASME B16.104 IV)
    • Soft seal (ASME B16.104 VI)

    Operating temperature:

    • Standard type -17~+230℃
    • Elongation type I (EI) -45~-17℃, +230~+566℃
    • Elongation type II (EII) -100~-45℃
    • Elongation type III (EIII) -196~-100℃


    • Pneumatic actuator: diaphragm type
    • Action mode: direct action, reverse action
    • Fault position: normally open, normally closed
    • Accessories: solenoid valve, electric positioner, limit switch, handwheel, position-keeping valve, air source filter
    • Electric actuator: intelligent regulating type and intelligent switching type
    • control signal:4-20mA


    What is a bellows sealed valve?

    Design and Structure
    Bellows sealed valves are engineered with an internal metallic bellows that forms a hermetic seal around the valve stem. This design prevents the escape of process fluids, ensuring zero leakage to the external environment. The bellows, typically constructed from stainless steel or other corrosion-resistant alloys, is welded to both the valve bonnet and the stem, providing a robust barrier against fluid migration.

    • Advantages of Bellows Sealed Valves
      Zero Emissions:The hermetic seal guarantees zero leakage, making these valves ideal for handling toxic, corrosive, or hazardous fluids.
    • Extended Service Life:The durable construction of the bellows extends the operational lifespan of the valve, reducing maintenance frequency.
    • Enhanced Safety:By preventing external leakage, bellows sealed valves enhance the safety of personnel and the environment.

    Bellows sealed valves are utilized across various industries where leak prevention is critical. Their application spans:

    • Chemical Processing:Handling aggressive chemicals and corrosive substances.
    • Pharmaceutical Manufacturing:** Ensuring contamination-free production environments.
    • Nuclear Power Plants:Managing radioactive fluids with utmost safety.
    • Oil and Gas Industries:Controlling hydrocarbons and other volatile compounds.

    bellows seal pneumatic single seat control valve

    What are the applications of bellows control valves?

    Bellows control valves are integral to industries where precision, safety, and reliability are paramount. Their unique design, featuring a sealed bellows assembly, ensures zero leakage and exceptional performance under harsh conditions.

    • Chemical Processing:Bellows control valves are indispensable in handling corrosive and hazardous chemicals. Their leak-proof design ensures safe and efficient management of aggressive fluids
    • Pharmaceutical Manufacturing:In environments where contamination control is crucial, bellows control valves provide unparalleled integrity.
    • Nuclear Power Plants:The highly sensitive nature of nuclear operations demands components that can withstand extreme conditions. Bellows control valves offer reliable control and isolation of radioactive fluids,
    • Oil and Gas Industry:In upstream and downstream applications, these valves handle high-pressure and high-temperature conditions with ease.
    • Semiconductor Manufacturing:The precision required in semiconductor fabrication processes benefits significantly from the use of bellows control valves.
    • Cryogenics:Handling extremely low temperatures is another domain where bellows control valves excel. Their robust construction ensures reliable operation in the storage and transfer of cryogenic fluids, such as liquid nitrogen and helium.