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The Function, Working Principle and Common Faults of Solenoid Valve

1. The Composition of the Solenoid Valve

The solenoid valve is a valve that controls the automatic opening and closing of the refrigerant in the refrigeration system. Solenoid valves can be divided into two types: direct-acting and indirect-acting. The solenoid valves used in commercial refrigeration equipment are generally direct-acting.
The solenoid valve is composed of two parts: the valve body and the solenoid head, which are generally direct-acting. between 22mm.

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Solenoid Valve

2. the role and working principle of the solenoid valve

1. The role of the solenoid valve:

The refrigeration system is divided into high pressure and low pressure, liquid and gas. In order to prevent the high-pressure liquid refrigerant from impacting the compressor after the compressor is stopped, a solenoid valve is used to protect it. When the compressor is started, the system pressure is in a balanced state, so there is no impact.

At this time, the solenoid valve is powered on and the compressor is turned on, and the refrigerant circulates and cools.
When the compressor is powered off when it is about to stop or the solenoid valve is cut off quickly after the stop, the refrigerant on the high-pressure side will not return to the compressor in the opposite direction but will pass through the compressor in the direction of the ring, and slowly the entire refrigeration system will have Equilibrium with the stop pressure of the compressor is slowly restored.

2. The working principle of the solenoid valve:

When the refrigeration equipment starts, the electromagnetic coil generates electromagnetic force to open the valve. When the coil in the electromagnetic head is energized, the coil and the armature generate an induced magnetic field, and the armature drives the valve needle to move up, the valve hole is opened, and the fluid flows normally. When the set temperature is reached, when the coil in the electromagnetic head is powered off, the magnetic field disappears, the armature falls by the rain and spring force, the valve needle closes the valve hole, and the fluid stops flowing.

3. Selection of solenoid valve

Generally, the solenoid valve with the appropriate nozzle diameter should be selected according to the flow rate of the system, and the parameters such as its working voltage, applicable ambient temperature, and working pressure should also be considered. When installing the solenoid valve, the valve body of the solenoid valve should be perpendicular to the pipeline to ensure that the solenoid valve spool can move up and down easily.

In order to ensure the tightness of the solenoid valve when it is closed, it is required that the flow direction of the medium in the system should be consistent with the nominal direction on the valve body of the solenoid valve. When installing the filter, the solenoid valve body should be fixed on the unit or bracket to avoid vibration and cause system leakage.

4. Common faults of solenoid valve

1. The power wiring is bad, just need to rewire or connect the plug-in;
2. The voltage of the power supply is unstable and needs to be adjusted in time to restore the voltage to the rated value;
3. The presence of impurities in the system causes the main spool of the solenoid valve or the moving iron spool to be stuck. It is necessary to clean the impurities in the system in time and then replace the solenoid valve;
4. The quality of the solenoid valve itself or the working life is too long, and it needs to be replaced with a new one;
5. The seal of the main valve core or the moving iron core is damaged and cannot be closed;
6. The spring of the solenoid valve fails, and the spring must be replaced in time;


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