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During the use of pneumatic valves, it is usually necessary to equip them with some auxiliary components in order to improve their performance or enhance their efficiency of operation. Common accessories for pneumatic valves include: air filters, directional solenoid valves, limit switches, electrical positioners, etc. In pneumatic technology, the combination of three air source treatment components – an air filter, a pressure reducing valve, and an oil mister – is known as a pneumatic trio. It is used to purify and filter the air supply intended for pneumatic instruments, as well as to reduce its pressure to the specified level required by those instruments; it functions similarly to a power transformer in electrical circuits. Types of pneumatic valve accessories: Double-acting pneumatic actuators: Two-position control for opening and closing the valve. (Dual-acting) spring-return actuator: The valve opens or closes automatically when the electrical or pneumatic supply is cut off or there is a fault. (Single-acting) Single-electric-control solenoid valve: The valve opens or closes when powered; it closes or opens when power is cut off (explosion-proof versions are available). Dual-control solenoid valve: The valve opens when one coil is energized and closes when the other coil is energized; it has a memory function (explosion-proof versions are available). Limit switch transmitter: Transmits signals indicating the on/off position of the valve over long distances (explosion-proof version available). Electrical positioner: Regulates and controls the flow rate of the medium through the valve based on the magnitude of the current signal (standard 4-20mA); explosion-proof versions are available. Pneumatic positioner: Regulates and controls the flow rate of the medium passing through the valve based on the magnitude of the air pressure signal (ranging from 0.02 to 0.1 MPa). Electrical converter: Converts current signals into air pressure signals for use with pneumatic positioners (explosion-proof versions available). Air source treatment trio: includes an air pressure regulator, a filter, and an oil mister, which serve to stabilize the air pressure, clean the air, and lubricate moving parts. Manual operating mechanism: Automatic control can be overridden manually in abnormal situations. Selection of pneumatic valve accessories: Pneumatic valves are complex automated control devices composed of various pneumatic components, and users need to make careful selections based on their control requirements. 1. Pneumatic actuator: ① Double-acting, ② Single-acting, ③ Model specifications, ④ Response time. 2. Solenoid valves: ① Single-control solenoid valve, ② Dual-control solenoid valve, ③ Operating voltage, ④ Explosion-proof type. 3. Signal feedback: ① Mechanical switch, ② Proximity switch, ⑧ Output current signal, ④ Operating voltage, ⑤ Explosion-proof type. 4. Positioners: ① Electrical positioners, ② Pneumatic positioners, ⑧ Current signals, ④ Air pressure signals, ⑤ Electrical converters, ⑥ Explosion-proof types. 5. Air source treatment trio: ① Filter pressure regulator, ② Oil mister. 6. Manual operating mechanism. Related articles: Pneumatic diaphragm actuators, Requirements for the quality of air supply in pneumatic actuators, Working principle of pneumatic actuators, Structure of pneumatic valve positioners, Maintenance and repair of pneumatic valves, Working principle of pneumatic control valves – animated diagram, Troubleshooting of faults in pneumatic control valves. Share to: Next article: Automatically closing spring-return ball valves – Malaysian brands