How to Choose a Solenoid Valve?

Solenoid valve is an industrial equipment controlled by electromagnetic, and it is an automatic basic component used to control fluid. It belongs to an actuator and is not limited to hydraulic and pneumatic. Used in industrial control systems to adjust the direction, flow, speed and other parameters of the medium. The solenoid valve can be matched with different circuits to achieve the desired control, and the control accuracy and flexibility can be guaranteed. There are many kinds of solenoid valves. Different solenoid valves play a role in different positions of the control system. The most commonly used ones are check valves, safety valves, directional control valves, speed control valves, etc. However, how to choose a right solenoid valve?

Safety

1. Corrosive medium: plastic king solenoid valve and all stainless steel should be used. For strong corrosive medium, isolation diaphragm type must be used. For neutral media, it is also advisable to use a solenoid valve with copper alloy as the valve shell material. Otherwise, rust chips often fall off in the valve shell, especially in occasions where the action is infrequent. Ammonia valves cannot be made of copper.
2. Explosive environment: Solenoid valves with corresponding explosion-proof grades must be selected, and waterproof and dust-proof varieties should be selected for outdoor installation or in dusty occasions.
3. The nominal pressure of the solenoid valve should exceed the maximum working pressure in the pipe.

Applicability

Medium characteristics

1. Choose different types of solenoid valves for gas, liquid or mixed state.
2. The viscosity of the medium is usually below 50cSt. If it exceeds this value, when the diameter is greater than 15mm, use a multi-function solenoid valve, and when the diameter is less than 15mm, use a high-viscosity solenoid valve.
3. When the cleanliness of the medium is not high, a recoil filter valve should be installed in front of the solenoid valve. When the pressure is low, a direct-acting diaphragm solenoid valve can be selected.
4. If the medium is in directional circulation and does not allow reverse flow, it needs to use two-way circulation.
5. The medium temperature should be selected within the allowable range of the solenoid valve.

Pipeline parameters

1. Select the valve port and model according to the medium flow direction requirements and the pipeline connection method.
2. Select the nominal diameter according to the flow rate and Kv value of the valve, or the same as the inner diameter of the pipeline.
3. Working pressure difference: the indirect pilot type can be selected when the minimum working pressure difference is above 0.04Mpa; the direct-acting type or step-by-step direct type must be used when the minimum working pressure difference is close to or less than zero.

Environmental conditions

1. The maximum and minimum temperature of the environment should be selected within the allowable range.
2. When the relative humidity in the environment is high and there are water droplets and rain, the waterproof solenoid valve should be selected.
3. There are often vibrations, bumps and shocks in the environment, and special varieties should be selected, such as marine solenoid valves.
4. For use in corrosive or explosive environments, the corrosion-resistant type should be selected first according to safety requirements.

Power conditions

1. According to the type of power supply, select AC and DC solenoid valves respectively. Generally speaking, AC power is easy to use.
2. The power supply voltage fluctuation is usually +%10%.-15% for AC, and ±%10 for DC is allowed. If it is out of tolerance, voltage stabilization measures must be taken.
3. The rated current and power consumption should be selected according to the power supply capacity. It should be noted that the VA value is high during AC starting, and the indirect pilot solenoid valve should be preferred when the capacity is insufficient.

Reliability

1. Work system: For the case where the valve is opened for a long time and only closed for a short time, a normally open solenoid valve should be used.
2. Operating frequency: When the operating frequency is required to be high, the structure should be preferably a direct-acting solenoid valve, and the power supply is preferably AC.

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