Pneumatic valve

Pneumatic steel lined PTFE flange ball valve is a type of valve used for fluid control, which can use double acting/single acting cylinders as driving actuators. The valve body can be made of cast steel WCB, and the lining material is PFA/FEP/PTFE. It can also be equipped with directional solenoid valves, limit switches, air pressure regulating filters, positioners and other accessories for assembly and use. Fluorine lining can effectively prevent corrosion, and with the installation of solenoid valves, remote control can be achieved to achieve electrical and pneumatic control; The feedback device (limit switch) can provide feedback on the valve position status; The air pressure regulating filter (two-piece) can optimize the driving air and regulate the air pressure; Positioners can enable proportional adjustment of valves through 4-20mA analog signal control or feedback.

‌一、结构设计‌

1. ‌阀体与衬里工艺‌：
   • The valve body is made of carbon steel (WCB/CF8) substrate, and the inner wall is integrally molded and lined with polytetrafluoroethylene (PTFE) with a thickness of ≥ 2.5mm, covering the flow channel and flange sealing surface, forming a fully lined anti-corrosion barrier.
   • Split type three piece flange structure (valve body+flange end caps on both sides), in compliance with GB/T 9119 flange standard, with uniform bolt pre tightening force to avoid stress cracking of the lining layer.
2. ‌密封系统‌Floating ball structure, the contact surface between the valve seat and the ball is synchronously lined with PTFE, and the valve seat is pushed by the medium pressure to form a self tight seal, with a leakage level of GB/T 13927A.
3. ‌驱动方式‌Equipped with a dual acting pneumatic actuator, the valve stem is driven by compressed air to achieve 90 ° rotation, supporting switch or adjustment control, and remains in place when power is cut off.

‌二、材质配置‌

• ‌基体材质‌：
  • Valve body/flange: Carbon steel WCB (GB/T 12229) or stainless steel CF8 (ASTM A351), with sandblasting treatment before lining to enhance PTFE adhesion.
  • Sphere: 304 or 316 stainless steel (ASTM A182), surface polished to Ra ≤ 0.8 μ m to reduce frictional resistance.
• ‌衬层与密封‌：
  • Lining material: Modified PTFE (containing carbon fiber or glass fiber reinforcement), temperature resistance range -50 ℃~180 ℃, strong acid, strong alkali and organic solvents (such as hydrochloric acid, hydrofluoric acid, acetone).
  • Valve stem: 17-4PH precipitation hardened stainless steel (ASTM A564), surface nickel plating treatment, torsional strength ≥ 800MPa.
  • Packing: Reinforced with flexible graphite and stainless steel wire, pre pressed to ensure low friction and long service life.

‌三、标准规范‌

• ‌设计标准‌GB/T 12237 (Petrochemical Industry), API 608 (Fireproof Structures).
• ‌衬里工艺‌HG/T 3704 (Technical Conditions for Steel lined PTFE Equipment), with no bubbles or pinholes in the lining layer, tested by 20kV electric spark.
• ‌法兰接口‌GB/T 9119 PN16~PN40 or ANSI B16.5 Class 150~300, sealing surface coated with PTFE layer (FF type).
• ‌性能测试‌：
  • Shell test: 1.5 times nominal pressure (GB/T 13927).
  • Sealing test: 1.1 times nominal pressure, helium mass spectrometry leak detection rate ≤ 10 ⁻⁶ mbar · L/s (ISO 15848).

‌四、技术参数‌

• ‌压力等级‌PN16/PN25 (conventional fluorine lined valve), specially designed to reach PN40.
• ‌适用介质‌Highly corrosive liquids/gases (such as 98% sulfuric acid, 30% hydrochloric acid, chlorine gas, etc.).
• ‌气动执行器‌：
  • Working pressure: 0.4~0.7MPa, double acting cylinder compatible with ISO 5211 standard installation interface.
  • Protection level: IP65 (GB/T 4208), optional explosion-proof type (Ex d IIC T4).

‌五、应用优势‌

1. ‌耐腐蚀性‌PTFE lining isolates the medium from contact with metals and is suitable for strong acids, strong bases, and mixed solvents with a concentration of over 98%.
2. ‌低维护成本‌The modular structure supports quick replacement of valve seats and packing without the need to disassemble pipelines.
3. ‌精准控制‌Pneumatic actuators can be integrated with locators to achieve 4-20mA signal feedback with an adjustment accuracy of ± 1% F.S.
4. ‌安全性‌Fireproof and anti-static design (according to API 607), a conductive spring with a resistance value of less than 10 Ω is installed between the ball and the valve stem.

‌六、典型应用‌

• ‌化工行业‌Pickling pipeline, pesticide reaction kettle feeding system, chlor alkali industrial brine treatment.
• ‌环保工程‌Control of circulating liquid in waste gas treatment tower and electroplating wastewater pipeline.
• ‌制药领域‌High purity solvent transportation and CIP/SIP cleaning system.