1、 Working principle of solenoid valve - Introduction
Electromagnetic valve, also known as Electromagnetic value in English, is an automated basic component used to control fluids. It is commonly used in industrial control systems to adjust parameters such as direction, flow rate, and velocity of media. Electromagnetic valves have the characteristics of high precision, good flexibility, multiple models, and wide applications. Electromagnetic valves can be divided into various types, and different electromagnetic valves can play their roles in different positions of the control system.
2、 Working principle of solenoid valve
There is a sealed chamber inside the solenoid valve, with a piston in the middle and two electromagnets on both sides of the chamber. Once the electromagnetic coil is energized, the valve body is attracted to the direction of the energized electromagnet by force; And there are through holes at different positions in the chamber, connecting different oil pipes, so the part of the oil discharge hole can be selected to be opened by controlling the movement of the valve body; Due to the oil inlet being in a normally open state, the movement of the valve body allows hydraulic oil to enter different oil discharge pipes. The pressure of the oil pushes the piston of the cylinder, which in turn pushes the piston rod, thereby driving the mechanical device. By utilizing this principle, it is possible to achieve the function of controlling mechanical motion by controlling the on/off of electromagnetic current.
3、 Working principle of solenoid valve - classification
Electromagnetic valves can be classified into various types based on their functions, such as water solenoid valves, high-pressure solenoid valves, fire solenoid valves, etc. They can also be classified into six types based on valve structure, materials, etc.: direct acting diaphragm structure, pilot diaphragm structure, distributed direct acting piston structure, etc. However, the most important classification method for solenoid valves is based on their principles, which can be divided into three types: direct acting solenoid valves, step-by-step direct acting solenoid valves, and pilot operated solenoid valves. Next, let's take a look at the differences in the principles of these three types of solenoid valves?
4、 Working principle of solenoid valve - direct acting solenoid valve
When the direct acting solenoid valve is powered on, it generates magnetic force through the electromagnetic coil to lift the closing member from the valve seat and open the valve, controlling the movement of the mechanical device; When the power is cut off, the electromagnetic force disappears, and the closing member is re pressed against the valve seat by the spring, causing the valve to close.
5、 Working principle of solenoid valve - pilot operated solenoid valve
When the pilot operated solenoid valve is powered on, the electromagnetic coil generates electromagnetic force to open the pilot hole, causing a sharp drop in pressure in the upper chamber and creating a high pressure difference between the upper and lower parts at the closing part. As a result, the closing part is pushed upward by pressure, and the valve is opened; When the power is cut off, the electromagnetic force disappears, and the pilot hole closes under the action of the spring, forming a pressure difference of high and low at the closing part, which then pushes the closing part downwards and closes the valve.
6、 Working principle of solenoid valve - step-by-step direct acting solenoid valve
The step-by-step direct acting solenoid valve combines the working principles of direct acting and pilot operated solenoid valve switches. When there is no pressure difference at the inlet and outlet or the pressure difference is small enough to push the valve to move, the valve is opened by the action of electromagnetic force (similar to the direct acting solenoid valve); When the pressure difference between the inlet and outlet can push the valve to move, use the pressure to open the valve (similar to a pilot operated solenoid valve); After power failure, when there is no pressure difference or electromagnetic force, the valve closes under the action of the spring.
In summary, the working principle of solenoid valves is to control the valve opening and closing by controlling the power on and off of the solenoid coil, thereby controlling the movement of the mechanical device. The difference in the working principle of the three types of solenoid valves lies in the different ways in which the solenoid coil opens and closes the valve.
