What is the difference between motorized valve and solenoid valve?

Hotowell will show you the difference between electric valve and solenoid valve! Both electric valve and solenoid valve are commonly used industrial equipment. Solenoid valve is also a kind of electric valve in a strict sense, but in general sense, we will distinguish between the two. So what is the difference between the two devices with only one word difference, the following content will give you the answer.

What is a solenoid valve? 

Solenoid valve is industrial equipment that uses electromagnetic force to control the medium. The control object includes but is not limited to hydraulic and pneumatic. It is a device that can be turned off quickly.

Classifying by principle, solenoid valves can be divided into pilot type, direct-acting type, and distributed direct-acting type according to their working principles.

Pilot solenoid valve

Principle: The energized coil generates magnetic force to open the pilot hole, the pressure in the upper chamber drops rapidly, and a high pressure difference is formed around the closing part. The medium pressure pushes the closing part to move upward and the valve opens; when the power is off, the magnetic force disappears and the spring force The pilot hole is closed, the inlet pressure passes through the bypass hole and the chamber quickly forms a lower and upper pressure difference around the valve closing member, and the medium pressure pushes the closing member to move downward to close the valve. The pneumatic solenoid valve shown in the picture is a pilot type. Features: The upper limit of the fluid pressure range is high, and you can choose any installation method, both horizontal and vertical.

Note: The pilot solenoid valve has requirements for low pressure of the medium. If the pressure is too low, the solenoid valve will not operate normally. This should be paid attention to when using and maintaining.

Direct Acting Solenoid Valve

Principle: As the name implies, a direct-acting solenoid valve is that when energized, the coil generates magnetic force to lift the closing part from the valve seat to open the valve; when the power is off, the magnetic force disappears, and the spring pushes the closing part back to the valve seat and the valve closes. Features: Because the magnetic force directly drives the closing part, there is no requirement for medium pressure, and the solenoid valve can work normally when there is no medium.

Note: The diameter of direct-acting solenoid valves generally does not exceed 25CM. Some hydraulic stations or small-diameter liquid control solenoid valves use direct-acting structures. Features: Because the magnetic force directly drives the closing part, there is no requirement for medium pressure, and the solenoid valve can work normally when there is no medium.

Step-by-step direct-acting solenoid valve

Principle: It is a combination of direct acting and pilot solenoid valve. When there is no pressure difference, the magnetic force directly lifts the pilot small valve and the main valve closing member upwards in turn, and the valve opens. When the inlet and outlet reach the starting pressure difference, the electromagnetic force pilots the small valve, the pressure in the lower chamber of the main valve rises, and the pressure in the upper chamber drops, so that the pressure difference pushes the main valve upward; when the power is off, the pilot valve uses spring force or medium The pressure pushes the closing piece and moves downward to close the valve.

Features: The action is not affected by the pressure of the medium, but the power is large, and it must be installed horizontally due to structural reasons. Solenoid valves with larger diameters often use this structure.

The solenoid valve has a simple structure and generally only has two states: on and off. Although the structure of the solenoid valve is not complicated, it is more precise, so the cleanliness of the medium is relatively high, and excessive impurities will affect the normal operation of the solenoid valve.

What is a motorized valve?

A motorized zonevalve, in simple terms, is a device that uses an electric actuator to switch the valve, that is, an electric actuator is used to control the valve instead of manpower.

From the structure of the motorized valve, it can be seen that the valve body is not much different from the ordinary manual valve. The difference is that the hand wheel is replaced with an electric actuator.

Electric actuators can perform linear and rotary movements, so in theory, manual valves can have electric versions, and there are electric gate valves, electric butterfly valves, electric ball valves, electric air duct valves and other electric zone valves. Electric actuators generally use motors as power to drive the deceleration device, and control the valve through the corresponding mechanism. Therefore, the switching action of the motorized valve is much slower than that of the solenoid valve. It not only has the open and closed state, but also can adjust the valve switching amplitude according to the given signal.

The electric control valve currently used is mainly used for the water-gas balance of the cross-linked vulcanization pipeline, and the purpose of sealing the nitrogen in the pipeline is achieved by adjusting the water flow. The electric actuator of the regulating valve is mainly composed of a single-phase servo motor, a servo controller, a deceleration device, a drive screw, a position limit switch, and a position feedback potentiometer. When working, the differential pressure transmitter transmits the output signal to the water level meter, and the water level meter outputs the signal to the servo controller according to the set water level value. The servo controller controls the action of the motor to achieve the purpose of controlling the water and air balance.

Compared with the solenoid valve, the structure of the motorized zone valve is more complicated, and the required circuit is also more complicated. However, because it is driven by a motor, the ability to withstand voltage shocks is better, so the service life of the electric valve is longer than that of the solenoid valve, and the failure rate is also lower. The electric actuator has a large torque, which can be used to control large pipe diameters and large flow. The disadvantage is that the speed is slow.

From the above content, we can see:

Solenoid valves are mainly used in small diameter and small flow occasions; the switching speed is extremely fast; the coil has poor resistance to voltage shock and is easily damaged; it has high requirements for the cleanliness of the medium.

Electric valves are mainly used in the occasions of large diameter and large flow; the switching speed is relatively slow; the ability to withstand voltage shocks is strong, and the failure rate is low; there are basically no special requirements for the cleanliness of the medium.

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