Pneumatic valve

The fork type pneumatic V-shaped clamp ball valve is mainly designed for flow control and can also be used for closing. Pneumatic actuators typically use single acting actuators because single acting actuators can better achieve gas free cutting, and the notch ports on segmented balls help to cut media and particles with fibers under strong shear stress. Therefore, this pneumatic V-type clamp ball valve is a good universal control valve application for most pulp and paper processes or similar flows containing fibers and particles.

一、结构与传动设计‌

1. ‌拨叉式执行机构‌：
   • Adopting a fork cam mechanical transmission structure, the linear motion of the pneumatic actuator is converted into a 90 ° rotation of a sphere. Compared with gear transmission, the torque transmission efficiency is increased by more than 15%, and there is no risk of backlash wear, making it suitable for high-frequency opening and closing scenarios.
   • The actuator cylinder is equipped with a low friction coefficient guide bearing and is designed with a shift fork limit block to ensure a repeat positioning accuracy of ≤ 0.5 ° for the fully open/closed position, with better action stability than traditional linkage mechanisms.
2. ‌V型球体与对夹结构‌：
   • The surface of the ball core is processed with a precision V-shaped notch of 60 °~90 °, which is matched with the valve seat to form a progressive flow regulation curve (with equal percentage characteristics), with a regulation ratio of 100:1, suitable for the dual requirements of precise truncation and flow control.
   • The clamp type installation complies with the GB/T 12221 standard, and the flange spacing is compatible with the HG/T 20592 series. The valve body length is shortened by 30% compared to the flange type, saving pipeline space, especially suitable for renovation projects or compact equipment integration.

‌二、核心材质与工艺‌

• ‌阀体与球体‌：
  • The valve body is made of CF8M stainless steel (ASTM A351) or WCB carbon steel (surface sandblasted+epoxy coating), with a pressure rating covering PN16~PN63 (GB/T 12224).
  • The V-shaped spherical substrate is made of ASTM A182 F316L stainless steel, and a tungsten carbide layer is deposited on the cutting edge area by supersonic flame spraying (HVOF). The surface hardness is ≥ HRC62, and the wear resistance is improved by 40% compared to ordinary hardening treatment.
• ‌密封系统‌：
  • Soft sealing solution: The valve seat adopts reinforced PTFE (30% fiberglass filling), with a temperature resistance of -29 ℃~180 ℃, and a leakage level that meets GB/T 13927 Class VI (≤ 6 × 10 ⁻⁶ mbar · L/s).
  • Hard sealing solution: The ball and valve seat are welded with Stellite 21 alloy, which has a temperature resistance of up to 450 ℃ and particle erosion resistance that meets the API 6D standard. The leakage level is Class IV.
• ‌阀杆与填料‌：
  • The valve stem material is 17-4PH precipitation hardened stainless steel (ASTM A564), with a surface treated with hard chrome plating (thickness ≥ 50 μ m) and a torsional strength ≥ 920MPa.
  • The stuffing box adopts a three-layer combination seal: the bottom layer is a flexible graphite ring, the middle layer is a PTFE V-ring, and the upper layer is equipped with Inconel 718 spring pre tensioning to ensure low friction and long-term sealing reliability.

‌三、性能参数与认证‌

• ‌操作条件‌：
  • Working pressure: -0.1MPa~10.0MPa (vacuum to high pressure condition).
  • Temperature range: -196 ℃ (deep cold hard seal)~450 ℃ (high temperature hard seal).
  • Gas source pressure: 0.4~0.7MPa, single acting spring reset type is optional (automatically returns to its original position in case of malfunction).
• ‌执行器特性‌：
  • Output torque: 80~3500Nm (suitable for DN15~DN200 caliber), repeat positioning error ≤± 0.3 °.
  • Protection level: IP67 (dustproof and waterproof shell), explosion-proof version complies with Ex d IIB T4 Gb (GB 3836).
• ‌测试标准‌：
  • Shell strength test: 1.5 times nominal pressure, holding time ≥ 5 minutes (GB/T 13927).
  • Fire safety: Through API 607 30 minute fire test, the sealing performance remains intact.
  • Life test: Soft sealed version opens and closes ≥ 100000 times, hard sealed version ≥ 50000 times (ISO 5208).

‌四、应用场景与优势‌

1. ‌严苛介质控制‌The V-shaped blade cuts fibers, powders, or crystalline particles during the closing process to prevent jamming, and is suitable for conveying paper pulp, chemical suspensions, or mining tailings.
2. ‌高精度调节‌Fork drive combined with intelligent locator (4-20mA signal), adjustable linearity ≤ ± 2%, can be integrated into DCS/PLC automation system.
3. ‌维护便捷性‌The clamp type valve body and modular fork assembly support online quick disassembly, and the replacement of seals or spheres does not require dismantling the pipeline, reducing maintenance time by 50%.