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What problems should be paid attention to when choosing to use solenoid valve?

                       
Update:08-12-2020
Summary:

The structure of the solenoid valve is not too complica […]

The structure of the solenoid valve is not too complicated, and the price is not too expensive, but it is possible to maximize its function by choosing it correctly and using it reasonably. If it is selected incorrectly, not only it will not work normally, but it will even cause control in serious cases. The system is abnormal. When choosing to use solenoid valves, the following issues should be noted.

 

(1) Understand the nature of working fluid
The nature of the working fluid determines the type of solenoid valve. Therefore, the corresponding solenoid valve should be selected according to the characteristics of the medium. For example, solenoid valves for water and steam are different. Fluid properties include: temperature, pressure, viscosity, corrosiveness, etc.; for fluids with high temperature, normal temperature solenoid valve cannot be used, otherwise its service life will be greatly shortened, or even damaged in severe cases. When the fluid in the pipeline contains particles and other impurities, a diaphragm solenoid valve should be used. The allowable liquid viscosity of the solenoid valve is generally below 20mm2/s, so please check with the manufacturer. If it is greater than 50mm2/s, it should be specially ordered. Generally, solenoid valves have high requirements for fluid cleanliness. When fluid cleanliness is not high, a filter can be installed in front of the solenoid valve.

(2) Find out the pressure and flow of working fluid
The selected rated working pressure of the solenoid valve is too high, which will increase investment; but the selected rated working pressure is too low, or close to the actual medium pressure, the solenoid valve will cause accidents due to insufficient material strength during operation. In addition to safety issues, the choice of working pressure is also related to whether the solenoid valve can work normally. Working pressure generally uses the highest and lowest upper and lower limits to determine its reliable working range. Otherwise, the solenoid valve will not work reliably under the influence of medium pressure.
The size of the medium flow is related to the diameter of the solenoid valve or the size of the valve seat. If the selected solenoid valve diameter is too large, it will cause economic waste and increase installation costs. However, if the diameter is selected, there will be more problems. For example, it will limit the flow that should pass through the pipeline and cause greater pressure loss, making the system The control effect is reduced, so that the control accuracy of the system is reduced or out of control.
Working pressure difference refers to the pressure difference between the inlet and outlet of the solenoid valve that can be reliably opened and closed. It is the key to whether the solenoid valve can work normally. It is also the primary consideration when selecting. It can be based on parameters such as process pipeline conditions. Combine the selection samples of solenoid valves for selection.

(3) Choose the working power supply
The operating power of the solenoid valve is divided into DC and AC, so you must pay attention when using the solenoid valve. Otherwise, the DC solenoid valve is connected to the AC power supply, and its electromagnetic attraction is very small and cannot work; if the AC solenoid valve is connected to the DC power supply, there will be excessive current and the coil temperature will increase and the solenoid valve will burn out.
The power supply of the solenoid valve should be consistent with the rated voltage on the nameplate. Because the power supply voltage is too high, the solenoid valve will have excessive current and abnormal temperature rise, and the electromagnetic suction will cause excessive impact, which will affect the reliability of the valve. If the power supply voltage is too low, the electromagnetic suction of the solenoid valve will drop too much, which will affect the valve opening ability, and it will be difficult to work reliably.

(4) Determine the operating frequency of the valve as required
The working frequency is the maximum number of operations allowed by the solenoid valve in use, and is usually expressed by the number of times the valve is opened and closed per minute. It is determined by the type and structure of the solenoid valve. For example, the direct-acting solenoid valve has a faster action time, and its working frequency can be higher.
Industrial production includes continuous production, intermittent production, and short-term production. If a solenoid valve with short-time duty is used in continuous production, its service life will be shortened, and it will even be damaged in a short time. Therefore, when selecting a solenoid valve, a reasonable selection should be made according to the production situation and the selection samples of the solenoid valve manufacturer. If there is no suitable product to choose from, you can only use the product with a higher gear instead of derating.

(5) Pay attention to details
Many solenoid valves can be used universally, so on the basis of meeting the requirements of use, the most economical product should be selected. Generally, solenoid valves are not waterproof, so make necessary choices for the installation environment. For corrosive media, stainless steel products should be used; solenoid valves have two types: normally closed and normally open. Normally closed type is open when energized and closed when power off; otherwise, it is normally open, which can be selected according to process requirements and safety .

(6) Pay attention to environmental conditions
To make the solenoid valve work reliably, the environmental conditions of its installation on site are also very important, such as:
The maximum temperature cannot exceed the nameplate of the solenoid valve. If the operating temperature of the solenoid valve is too high, the service life will be reduced. If the ambient temperature is too low, it will cause frosting of the solenoid valve casing, causing problems in the sealing packing, etc., and making the solenoid valve unable to work normally.

Relative humidity will affect the electrical insulation, and a humid environment will reduce the electrical insulation and affect the reliability of the solenoid valve. If the humidity is too high, it is easy to cause mold and so on at a certain temperature. When the operating environment has dust, water droplets, salt spray, and corrosive atmosphere, consider their influence on the solenoid valve. Choose products with good sealing properties, such as waterproof, splash-proof, and dust-proof solenoid valves. When the use environment requires explosion-proof, explosion-proof solenoid valve should be selected. Vibration-resistant solenoid valves should be selected in environments with vibration and shock. In addition to selecting the solenoid valve correctly for the above environment, certain protective measures should be taken to protect the solenoid valve.

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