Screw air compressor intake valve working principle

- Oct 08, 2019-

The air compressor intake valve can also be said to be an intake control combination valve, which has the functions of intake control, loading and unloading control, tolerance control, discharge, prevention of unloading or fuel injection during shutdown. Now let's take a look at the working principle of the intake valve of the screw air compressor and the reasons and solutions for the opening of the intake valve.


Screw air compressor intake valve working principle

A general rule for the screw air compressor intake valve is that the intake valve is electrically loaded and de-energized.


Sometimes our equipment has a slightly larger current in the case of unloading (the current is 31A when the 22KW is unloaded). It is suspected that the intake valve is not closed, because when the machine is not used, the pressure is still after the machine is unloaded. Will slowly rise, sometimes high pressure alarm shutdown! Moreover, after the machine is stopped, there is still some residual pressure inside the machine that cannot be discharged (about 6 kg), which causes the main engine to be overloaded when starting again.


When the screw air compressor intake valve is a normally open intake valve, the solenoid valve is opened when the screw air compressor is not loaded, and the solenoid valve is closed after the compressor is loaded. When the solenoid valve is opened, there will be a way to close the intake valve, but it cannot be completely shut down, and the intake space is reserved to maintain the minimum pressure required for the compressor to be lubricated. This pressure is generally 1.5 bar; the solenoid valve is closed. After that, the compressor will enter normal operation until the set working pressure, depending on the user.


The intake valve has two pipes, one of which is vented; one way to release the residual gas in the valve to ensure normal loading of the compressor. When unloading, the current is too large, indicating that the tank pressure is high and the intake valve opening is large. Please adjust the venting screw to ensure that the tank pressure is not too high.


After the screw air compressor is shut down, the tank pressure can be completely emptied in about 60 seconds, that is, the pressure is 0, and your tank pressure is 6 bar, indicating that there is a problem with the intake valve vent line:


It may be that the pipe diameter is too thin; the orifice of the combination valve is too small or if the debris is clogged.


After unloading, the pressure will rise slightly back and forth, but this is just a balance and it takes a short time. It will not rise to high pressure shutdown. The high pressure shutdown should be a problem with the air compressor solenoid valve. Please check if it is in good condition and it can work normally. Regardless of the type of intake valve, the tank pressure should be maintained between 1.0 and 2.0 BAR when unloading. Too high is a great waste of energy for the screw air compressor.


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Reasons and solutions for the intake valve not open

The intake valve of the screw air compressor is a component that controls the air pressure in the gas storage tank. The commonly used intake valve has a rotating disc structure and a reciprocating valve plate mechanism. The disc or the valve plate is used to open or close the air inlet, and the control enters. Airflow from the nose.


There are two control modes: one is the switch. When the pressure of the gas tank reaches the high limit setting value, the air inlet is closed, and when the pressure drops to the low limit setting value, the air inlet is reopened. The other is that when the gas tank reaches a certain pressure, the rotating disc is slightly closed to the air inlet under the control of the proportional valve. When the pressure of the gas tank is further increased, the air inlet is further reduced when the air tank pressure When there is a slight decrease, the air inlet will be increased to stabilize the pressure within a certain range. When the pressure does not reach the tolerance pressure, the intake valve disc is fully open and the air inlet is fully open.


In the case of operation, the reason for the closing of the intake valve of the screw air compressor and the solution:


1. Control the water in the pipeline too much, and maintain the control pipeline every day.


2. The intake valve works incorrectly; check the cylinder, valve sleeve and other parts and replace if necessary.


3. The air intake valve is stuck; check the intake valve, valve sleeve, or shaft and replace if necessary.


4. The intake valve spring is broken; replace the spring.


5. Solenoid valve failure; Repair or replace as needed, check wiring before replacement.


6. The shuttle valve is damaged; repair or replace.


7. The solenoid valve wire connector is loose; check and tighten the wire terminal.


These will cause the screw air compressor intake valve to malfunction, and should be handled with caution during production operations. The intake valve is generally a normally closed valve to prevent a large amount of gas from entering the machine head during starting, and increasing the starting current of the motor.


There is an intake bypass valve on the intake valve of the screw air compressor to prevent the machine from starting and emptying, and a high vacuum is formed in the machine head, which affects the atomization of the lubricating oil.