The principle of electric and pneumatic valves:
Electric valves usually consist of electric actuators and valves. Simply put, it means using an electric actuator to control the valve, thereby achieving the opening and closing of the valve. It can be divided into two parts: the upper part is an electric actuator, and the lower part is a valve. Electric valves use electricity as power to drive the valve through an electric actuator, achieving the opening and closing action of the valve, thereby achieving the purpose of opening and closing the pipeline medium.
The action force distance of electric valves is larger than that of ordinary valves, the opening and closing speed can be adjusted, the structure is simple, and it is easy to maintain. It can be used to control the flow of various types of fluids such as air, water, steam, various corrosive media, mud, oil products, liquid metals, and radioactive media.
Pneumatic valves are valves driven by compressed air. By using compressed air to drive multiple sets of combined pneumatic pistons inside the actuator, the characteristics of transmitting force to the crossbeam and inner curved track drive the hollow spindle to rotate. The compressed air is transported to each cylinder and the inlet and outlet positions are changed to change the direction of spindle rotation. According to the requirements of the required rotation torque of the load (valve), the cylinder combination can be adjusted to drive the load (valve) to work.
Two position five way solenoid valves are usually used in conjunction with double acting pneumatic actuators, with two positions being controllable: on and off. The five way valve has five channels for ventilation, one of which is connected to the air source, two are connected to the inlet and outlet of the external air chamber of the double acting cylinder, and two are connected to the inlet and outlet of the internal air chamber. The specific working principle can refer to the working principle of the double acting pneumatic actuator. Due to the increasing number of control methods and means, there are also many methods used to control pneumatic actuators in practical industrial production and industrial control.
Pneumatic valves can be used to control the flow of various types of fluids such as air, water, steam, various corrosive media, mud, oil products, liquid metals, and radioactive media.
The advantages of electric and pneumatic valves respectively:
1. Pneumatic valves have good effects on gas media and small diameter liquids, low cost, and convenient maintenance. Disadvantage: Due to the fluctuation of air compressor pressure, it is easily affected by water content in the air compressor during winter in the north, causing the transmission part to freeze and not move. Generally, pneumatic power is faster than electric power, and electric power is dual-purpose. In the absence of pneumatic drive, the price of using both hand and air is generally higher;
2. Electric valves have good effects on liquid media and large diameter gases, and are not affected by climate. Not affected by the pressure of the compressed air. Disadvantages: high cost and poor performance in humid environments;
3. Electric valves operate slowly, and there are not many brands of electric valves that can achieve explosion-proof performance; Pneumatic valves act quickly and are relatively cheaper in terms of explosion-proof compared to electric valves;
4. The electric actuator of electric valves may experience tooth jamming for a long time, while pneumatic valves have fast switching speed and high accuracy, but require a stable air source.