Shanghai Kaizhi ZJHP-16C DN25 Pneumatic Control Valve 1.6MPa

Due to the large number of models, please consult customer service for specific models, specifications, and prices!Shanghai Kaizhi ZJHP-16C DN25 Pneumatic Control Valve 1.6MPa

Pneumatic control valve is one of the industrial process control instruments widely used in petroleum, chemical, power, metallurgical and other industrial enterprises. Pneumatic control valves are usually formed by connecting, installing, and debugging pneumatic actuators, valves, positioners, and other components. The working principle of pneumatic control valve is to use compressed air as the power source, cylinder as the actuator, and accessories such as electrical valve positioner, converter, solenoid valve, and holding valve to drive the valve, achieve on/off or proportional adjustment, and receive control signals from industrial automation control system to adjust various process parameters such as flow rate, pressure, and temperature of pipeline medium. The characteristics of pneumatic control valves are simple control, fast response, and inherent safety, without the need for additional explosion-proof measures. Common faults and causes of pneumatic control valves: Firstly, the control valve does not operate. The fault symptoms and causes are as follows: 1. No signal, no gas source. ① The gas source is not turned on, ② due to the water content in the gas source freezing in winter, the air duct is blocked or the filter and pressure reducing valve are blocked and malfunctioning, ③ compressor failure; ④ The gas source main pipe is leaking. 2. There is a gas source but no signal. ① Regulator malfunction; ③ The locator bellows is leaking air; ④ Adjust the damage of the omentum plate. 3. The locator has no air source. ① Filter blockage; ② Pressure reducing valve malfunction I ③ Pipeline leakage or blockage. 4. The locator has a gas source but no output. The throttle hole of the locator is blocked. 5. There is a signal but no action. ① Valve core detachment, ② valve core jamming with society or valve seat; ③ The valve stem is bent or broken; ④ The valve seat and valve core are frozen or contaminated with coke blocks; ⑤ The actuator spring has rusted due to long-term disuse. 2、 The action of the regulating valve is unstable. The fault symptoms and causes are as follows: 1. Unstable air source pressure. ① The compressor capacity is too small; ② Pressure reducing valve malfunction. 2. The signal pressure is unstable. ① The time constant (T=RC) of the control system is inappropriate; ② The regulator output is unstable. 3. The gas source pressure is stable, and the signal pressure is also stable, but the action of the regulating valve is still unstable. ① The ball valve of the amplifier in the locator is not tightly closed due to dirt wear, and when the air consumption increases significantly, it will produce output oscillation; ② The nozzle baffle of the amplifier in the locator is not parallel, and the baffle cannot cover the nozzle; ③ Leakage of output pipes and wires; ④ The rigidity of the executing mechanism is too low; ⑤ The friction resistance is high during the movement of the valve stem, and there is obstruction at the contact area. 3、 Adjust valve vibration. The fault symptoms and causes are as follows: 1. The regulating valve vibrates at any opening. ① Unstable support; ② There is a vibration source nearby; ③ The valve core and liner are severely worn. 2. The regulating valve vibrates when approaching the fully closed position. ① The regulating valve is too large and is often used at a small opening; ② The flow direction of the medium in a single seat valve is opposite to the closing direction. 4、 The action of the regulating valve is sluggish. The phenomenon and reasons for sluggishness are as follows: 1. The valve stem is only sluggish when it moves in one direction. ① Membrane damage and leakage in pneumatic membrane actuator; ② The "O" seal in the actuator leaks. 2. The valve stem exhibits sluggishness during reciprocating motion. ① There is adhesive blockage inside the valve body; ② Deterioration and hardening of polytetrafluoroethylene fillers or drying of lubricating oil with graphite asbestos fillers; ③ Adding too much filler increases frictional resistance; ④ Due to the non straight valve stem, there is high frictional resistance; ⑤ Pneumatic control valves without locators can also cause sluggish operation. 5、 The leakage of the regulating valve increases. The reasons for the leakage are as follows: 1. When the valve is fully closed, there is a large amount of leakage. ① The valve core is worn and has severe internal leakage, and the valve is not properly adjusted and cannot be tightly closed. 2. The valve cannot reach the fully closed position. ① The pressure difference of the medium is too large, the rigidity of the actuator is small, and the valve is not tightly closed; ② There are foreign objects inside the valve; ③ Lining sintering.