Pneumatic stainless steel ball valves are widely used in industrial automation control systems such as petrochemicals, pharmaceuticals, food, and electricity because of their compact structure, rapid opening and closing, and good sealing performance. However, during long-term operation or improper operation, the valve may also have various faults, affecting the stability and safety of the system. This article will classify and analyze the common faults of pneumatic stainless steel ball valves to help users improve troubleshooting efficiency and equipment maintenance level.
1. Valve leakage
1. Damage to the valve seat sealing surface: solid particles and impurities in the medium will scour and wear the valve seat sealing surface during the opening and closing process of the valve, resulting in uneven sealing surface and leakage.
2. Damage to the ball surface: During installation or use, the ball is subjected to external forces such as collision and extrusion, resulting in pits, scratches and other defects on the ball surface, which destroys the sealing performance of the ball and the valve seat.
3. Valve seat deformation: Excessive temperature changes, excessive medium pressure or long-term use may cause the valve seat to deform, resulting in the valve seat and the ball not fitting tightly, resulting in leakage.
2. Slow or stuck valve action
1. Gas source problem: Insufficient gas source pressure will make the pneumatic actuator drive force insufficient, resulting in slow valve action. In addition, impurities such as moisture and oil in the gas source will block the pneumatic pipeline or the internal channel of the actuator, affecting the gas flow and causing the valve to be stuck.
2. Actuator failure: Wear and aging of the piston seal of the pneumatic actuator will cause the piston to leak, causing the actuator output force to decrease and the valve to move abnormally. In addition, wear and oil shortage of transmission parts such as gears and racks of the actuator will also cause the valve to move inflexibly.
3. Internal valve problems: Impurities, rust, etc. in the valve accumulate between the ball and the valve seat or the rotating part of the valve, which will hinder the rotation of the ball and cause the valve to be stuck.
3. Valve cannot move
1. Solenoid valve failure: If the solenoid valve coil is broken, short-circuited or burned, the solenoid valve will not work properly and cannot control the on and off of the gas path, resulting in the valve being unable to move. In addition, problems such as the valve core of the solenoid valve being stuck and the sealing being not tight will also affect its normal function.
2. Control circuit problem: If the signal circuit controlling the pneumatic ball valve is broken, short-circuited or poorly contacted, the control signal cannot be transmitted normally to the solenoid valve or pneumatic actuator, causing the valve to fail to operate as required.
3. Actuator damage: Serious damage such as cylinder rupture and piston jamming of the pneumatic actuator will cause the actuator to lose its driving ability, causing the valve to fail to open and close.
4. Limit switch failure
1. Position offset: During the frequent opening and closing of the valve, vibration may cause the installation position of the limit switch to shift, so that the limit switch cannot operate at the correct opening and closing position of the valve, and thus cannot accurately feedback the valve status.
2. Contact damage: After long-term use, the contacts of the limit switch will be worn, oxidized, ablated, etc., resulting in poor contact or failure to conduct, so that the control system cannot receive the correct valve position signal.
The operating stability of the pneumatic stainless steel ball valve is related to the operating efficiency and safety of the entire automation system. In order to effectively prevent failures, it is recommended that users develop a comprehensive inspection plan, promptly remove impurities, check seals, test the quality of the electronic control system and air source, and perform periodic maintenance on the actuators and control components. Through "early detection and early treatment", not only can the service life of the valve be extended, but also the operation and maintenance costs can be reduced to ensure the continuous and efficient operation of the system.