Pneumatic check valve

气动止回阀is an automatic valve that combines pneumatic actuators, mainly used to prevent medium backflow and ensure the safety of pipeline systems and equipment. The core information is as follows:

1、 Definition and core functions
Definition: Integrating pneumatic control devices on the basis of traditional check valves (also known as check valves or one-way valves), the valve disc is opened and closed by compressed air to achieve one-way flow of the medium.
Core functions:
Quick shutdown: In case of system failure (such as sudden pressure drop or medium backflow), the pneumatic device can forcibly close the valve within 0.5 seconds to prevent equipment damage;
Anti backflow protection: Avoid medium reverse impact on critical equipment (such as steam turbines and compressors).
2、 Structure and working mechanism
Main components:
Valve body: Material selection according to working conditions (cast iron, carbon steel, stainless steel, etc.);
Valve disc and seal: The sealing surface is welded with hard alloy (such as Cr13 stainless steel, cobalt based alloy) to enhance wear resistance;
Pneumatic actuator: including cylinder, solenoid valve, and quick release valve, with a typical air source pressure of 0.4-0.6MPa.
Working principle:
Open: The air source drives the piston compression spring, releases the valve disc limit, and the medium flows forward to push open the valve disc;
Close: When power/gas is lost, the solenoid valve cuts off the gas source, the quick release valve releases pressure, and the spring/heavy hammer pushes the valve disc to close instantly.

‌电力行业‌：火力发电厂抽汽系统，防止蒸汽倒流击毁汽轮机叶片； ‌限位开关‌：实时监测阀门开闭状态（全开/全闭/部分开启）。
3、 Key application scenarios
Power industry: extraction system for thermal power plants to prevent steam backflow from damaging turbine blades;
Petrochemicals and Energy: Oil/gas pipelines, chemical processes, protection of compressors and downstream equipment;
General industry: occasions where backflow needs to be quickly cut off, such as water supply systems and thermal pipelines.
4、 Technical characteristics and selection
Closing speed: ≤ 0.5 seconds (forced closing type);
Design standards: comply with ASME B16.34, JB/T3595 and other specifications;
Special Design:
Heavy hammer balancing structure: balancing the self weight of the valve disc, reducing vibration and water hammer effects;
Limit switch: Real time monitoring of valve opening and closing status (fully open/fully closed/partially open).