What Is The Switch Control Principle Of Butterfly Valve Pneumatic Actuator? How To Hit The Pinpoint Switch?

Butterfly valve pneumatic actuator is a kind of automatic control device driven by compressed air. Compared with the motor drive mode of electric actuators, pneumatic actuators relies on pure pneumatic circuits and mechanical structure to complete opening and closing actions. Many in the industry only know its automatic switch function, but do not understand its internal switch control logic and precise opening and closing implementation principle. In this paper, the key principle of butterfly valve pneumatic actuators switch control is analyzed in detail, as well as the complete operating mechanism to realize high precision and zero deviation opening and closing.
The key principle of butterfly valves pneumatic actuator is to convert the potential energy of compressed air pressure into mechanical rotation energy, and drive butterfly valve plate to complete 90 degree opening and closing by air path switching, piston transmission and gear angle coupling. According to the structure, there are two kinds of control modes: double action control and single action control. The switching logic of the two methods is slightly different, but the core transmission principle highly consistent. Both are suitable for the opening and closing characteristics of the 90-degree rotary butterfly valves, and perfectly match the opening and closing control requirements of pipeline medium.
The double acting pneumatic actuator is a kind of universal switch structure, which relies on two-way alternating bidirectional air supply to realize switch control. The equipment is equipped with two separate air intake channels corresponding to the opening and closing stations. When the valve opens, the control system switches the air path through the solenoid valve, compressed air enters the chamber on the cylinder's side, propelling the piston to move in a straight line, driving the rack to shift, engaging through the gears, and driving the stem to rotate 90 degrees. The butterfly valve is fully open and the gas on the other side of the chamber is discharged automatically. When the valve closes, the air path switches in the opposite direction, compressed air enters the other side of the chamber, propelling the piston in the opposite direction, driving the valve plate to rotate and reset, completing closing operation. The whole process is driven by bidirectional air pressure and the switching motion is stable and controllable.
The single acting pneumatic actuator is a safety switch structure based on pneumatic drive opening and closing and spring reset and closing. It has a built-in reset spring, which retains only one set of working air paths. When the valve opens, compressed air enters the cylinder chamber, overcomes the spring force, propels the piston and gear transmission structure to move, drives the butterfly valve to open. At the same time, springs are compressed and store energy. When the valve closes, the inlet is cut off and the air pressure is released. The compressed spring immediately releases the stored energy, the drive drive transmission structure is reset in the opposite direction, and the drive butterfly valve automatically closes. Valves can be safely closed even in the event of a gas or electrical fault.
Based on the basic switch action, the device relies on a variety of precision structures to open and close valve accurately, eliminating problems such as improper opening and closing, too high positioning, deviation and shaking. First of all, it is a kind of high precision gear rack transmission structure with minimal clearance of components and no jamming or virtual position in transmission. It can convert the linear displacement of piston into a fixed angle rotation, ensure the precise control of the angle of each valve plate rotation, ensure the accuracy of opening and closing from the transmission level, and avoid the media leakage caused by the displacement of the valve plate.
Secondly, adjustable mechanical limiting device is the core guarantee of precise opening and closing. The two ends of the The actuator are equipped with special limiting screws, which can lock the fully open and fully closed limiting positions according to the working conditions. The equipment can be calibrated accurately when leaving the factory. In the course of operation, the valve stem rotates according to the setting angle, then locks the limiting structure firmly, completely eliminates problems of opening and closing, running too fast and so on, ensures that every switch can be fully opened and closed, effectively solves the common problems such as the valve half open and half closed, poor sealing.
At the same time, stable air pressure control system further improves the accuracy and consistency of opening and closing. Install solenoid valves and gas source pressure control valve, can continuously output stable air pressure, avoid the opening and closing force caused by the fluctuation of air pressure and stroke deviation. Uniform air pressure output ensures steady piston movement speed, uniform force distribution, smooth opening and closing movements, no shock opening and closing. This not only protects the valve sealing structure, but also ensures the uniformity and accuracy of batch opening and closing. High quality sealing components can also prevent air leakage and pressure release problems, ensure stable airway pressure, avoid air leakage caused by the opening and closing and positioning deviation.
In conclusion, butterfly valve pneumatic actuators realizes basic switch control by gas circuit switching and pneumatic transmission, and relies on three core mechanisms of gear rack precision transmission, mechanical limit locking and constant pressure gas source regulation to achieve high precision opening and closing. The whole control principle has simple structure, stable operation and low failure rate, which can satisfy the requirement of fast connection and disconnection of pipeline, and also ensure tight sealing, precise opening and closing, and meet the standard control requirements of chemical engineering, water treatment, gas and other industrial conditions.