After understanding pneumatic actuators to a certain extent, people may have a question, which is why pneumatic actuators have both single action and action. Because pneumatic valve actuators control the opening and closing of valves through ventilation and disconnection, different solutions need to be provided according to the different requirements of users:
A double acting pneumatic actuator starts to rotate and open the valve when the valve is ventilated. When the valve needs to be closed, the other side of the actuator is ventilated and can only be closed. It is reset by the cylinder and can only remain in place when the air source is lost;
Single acting pneumatic actuators open the valve when ventilated and automatically close when there is no air source available. Single acting pneumatic actuators rely on springs to automatically reset and are commonly used in hazardous conditions, such as conveying combustible gases or liquids. In the event of an emergency situation after losing the air source, single acting pneumatic actuators can automatically reset to reduce the risk, while double acting pneumatic actuators are generally not easy to reset.
Single acting pneumatic actuators are generally divided into normally open and normally closed types
Normally open type: ventilated off, disconnected on
Normally closed, ventilated on,
In general, the use of double acting cylinders is more common in air shut-off conditions, and double acting cylinders do not have springs, so the cost is lower than that of single acting pneumatic actuators
Function and purpose of pneumatic actuators and accessories
Double acting pneumatic actuator: Two position control for valve opening and closing.
Spring return type: When the circuit air circuit is cut off or malfunctions, the valve automatically opens or closes.
Single electric control solenoid valve: The valve opens or closes when powered on, and closes or opens when powered off (explosion-proof type available).
Dual electric control solenoid valve: When one coil is powered on, the valve opens, and when the other coil is powered on, the valve closes, with a memory function (explosion-proof type available).
Limit switch feedback device: remotely transmit the signal of the valve's switch position (explosion-proof type can be provided).
Electrical locator: Adjust and control the medium flow of the valve based on the size of the current signal (standard 4-20mA) (explosion-proof type can be provided).
Pneumatic positioner: adjusts and controls the medium flow rate of the valve based on the size of the air pressure signal (standard 0.02-0.1MPa).Electrical converter: Converts current signals into air pressure signals and is used in conjunction with pneumatic positioners (explosion-proof type available). Air source treatment triple unit: including air pressure reducing valve, filter, oil mist device, which has the function of stabilizing, cleaning, and lubricating moving parts of the air source.
Manual operation mechanism: Automatic control can be manually operated in abnormal situations.
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