Difference between solenoid valve and electric valve

1. Switch type:

The solenoid valve is driven by the coil and can only be opened or closed. The action time of the switch is short.

Electric valve drive is generally used motor, open or close action to complete the need for a certain amount of time analog, can be adjusted.

2. Nature of work:

The general flow coefficient of solenoid valve is very small, and the working pressure difference is very small. For example, the flow coefficient of 25 caliber solenoid valve is much smaller than that of 15 caliber electric ball valve. The drive of the solenoid valve is through the solenoid coil, which is easy to be damaged by voltage shock. It is equivalent to the function of the switch, that is, opening and closing two functions.

The electric valve is usually driven by a motor, which is more resistant to voltage shock. The solenoid valve is fast opening and fast closing, generally used in small flow and small pressure, requiring a large switching frequency of the electric valve on the contrary. The opening of the electric valve can be controlled, and the state includes opening, closing, half opening and half closing. It can control the flow of medium in the pipeline, but the solenoid valve can not meet this requirement.

Generally, the solenoid valve can be reset after power failure, and the electric valve needs to be equipped with reset device for such function.

3. Applicable process:

Solenoid valve is suitable for some special process requirements, such as leakage, special fluid medium, etc., and its price is relatively expensive. Electric valve is generally used for regulation, but also has switching value, such as: fan coil end.

As a kind of actuator of automatic instrument, the consumption of solenoid valve has increased rapidly in recent years. This paper analyzes the main characteristics of the solenoid valve, and focuses on the application of the perspective of the development of domestic mature technology briefly reviewed in the direction of fine simplification, intelligence, generalization and specialization, respectively, and briefly discusses the social factors affecting the development of the solenoid valve technology.

Main features of solenoid valve

(1) External leakage is blocked, internal leakage is easy to control and safe to use. Internal and external leakage is an element endangering safety. Other automatic control valves usually extend the valve stem, and the electric, pneumatic and hydraulic actuators control the rotation or movement of the valve core. All of these need to solve the leakage problem of long-term action valve stem dynamic seal; only the electromagnetic valve is completed by using the electromagnetic force to seal the iron core in the magnetic isolation sleeve of the electric control valve, and there is no dynamic seal, so the leakage is easy to be blocked. The torque control of electric valve is not easy, and it is easy to produce internal leakage, or even pull off the head of valve stem; the structure of solenoid valve is easy to control internal leakage until it is reduced to zero. Therefore, the use of solenoid valve is particularly safe, especially suitable for corrosive, toxic or high and low temperature media.

(2) Simple system, easy to connect computer, low price. The structure of the solenoid valve itself is simple and the price is low. Compared with other kinds of actuators such as control valve, it is easy to install and maintain. What's more, the automatic control system is much simpler and much cheaper. Because the solenoid valve is controlled by switch signal, it is very convenient to connect with industrial control computer. In today's era of computer popularization and sharp price decrease, the advantages of solenoid valve are more obvious.

(3) Action express, small power, light shape. The response time of the solenoid valve can be as short as several milliseconds, and even the pilot solenoid valve can be controlled within tens of milliseconds. Because of self-contained loop, it is more sensitive than other automatic control valves. The properly designed solenoid valve coil has low power consumption, which is an energy-saving product; it can also be used to trigger action and automatically maintain the valve position without any power consumption at ordinary times. The external dimension of the solenoid valve is small, which not only saves space, but also is light and beautiful.

(4) The adjustment accuracy is limited, and the applicable medium is limited. Generally, there are only two states of the solenoid valve: on-off and on-off. The valve core can only be in two limit positions and can't be adjusted continuously. (there are many new ideas trying to break through, but they are still in the trial stage.) therefore, the adjustment accuracy is still limited. The solenoid valve has a high requirement for the cleanliness of the medium. The medium containing particles cannot be used. If it is impurity, it must be filtered first. In addition, viscous media can not be used, and the viscosity range of specific products is relatively narrow.

(5) Various models and uses. Although the solenoid valve has inherent shortcomings, the advantages are still very prominent, so it is designed into a variety of products, to meet different needs, a wide range of uses. The progress of solenoid valve technology is also around how to overcome the inherent deficiencies, how to better play the inherent advantages and start.