Vacuum test using an external mechanical vacuum pump This method is generally used at small cold storage facilities. The specific operation steps are as follows:
(1) Unscrew the fine screw plug of the channel of the inhalation stop valve counterclockwise, rotate the suction valve stem several times in a clockwise direction to make the inhalation stop valve in the three-way state;
(2) Connect the vacuum pump to the multi-use interface on the suction shut-off valve with a soft connector with a three-way repair valve and a vacuum pressure gauge;
(3) Open all the valves in the system (including solenoid valves, manual valves, etc.);
(4) Turn on the vacuum pump power supply and vacuum the system until the reading of the vacuum gauge reaches -0.1 MPa. After a suitable time, the suction valve stem is rotated counterclockwise to withdraw and tighten;
(5) Hold for 18-24 hours. If the vacuum level does not change, it is considered that the vacuum test of the refrigeration system is qualified.
Self-vacuum test using the compressor in the system The vacuum test is commonly used for larger refrigeration systems using this method. The compressor in the system is used for self-evacuation. The specific operation steps are as follows:
(1) First select the exhaust stop valve stem clockwise so that the system loses its circulation path at the exhaust port of the compressor.
(2) Unscrew the fine screw plug of the multi-purpose channel of the exhaust stop valve counterclockwise to open the exhaust port to the atmosphere.
(3) Open all the valves in the system.
(4) Short the contact of the low voltage relay and temporarily remove the protection function (it must be restored afterwards).
(5) Start the compressor so that the air in the system will be discharged into the atmosphere (the suction valve of the compressor should be opened slowly to avoid the gas in the system from being discharged too late, resulting in high exhaust pressure and high pressure protection).
(6) Observe the vacuum gauge on the low pressure side until the reading of the vacuum pressure gauge reaches -0.1 MPa. After a suitable time, rotate the exhaust stop valve stem back out and tighten.
(7) Keep 18~24h, if the vacuum degree does not change, it is qualified. During the test, it should be noted that: 1. When self-priming the pressure-lubricated compressor refrigeration system, the contact of the hydraulic relay should be temporarily forced to connect; 2. The time for self-evacuation cannot be too long, otherwise the compressor The moving parts work at a higher temperature for a long time are prone to produce greater wear and metal fatigue; 3. In the self-evacuation test, a hose can be connected to the exhaust port and the other end of the hose can be inserted into the oil. In the observation of the escape of air bubbles on the surface of the oil. If no air bubbles escape for a long period of time, the vacuum can be stopped, and the vacuum degree does not change to pass after 24 hours. If the air bubble does not stop for a long time, you can turn off the suction valve of the compressor and check whether the compressor itself leaks. If there is no more air bubbles in the oil, it means that the compressor itself does not leak, and there is leakage in other parts of the system; daily bubbles still occur continuously. , Explain the compressor suction, which is often caused by the shaft seal is not tight.
For more information, please consult China Vacuum Pump Trading Network. (/)
Tube Printer,Tube Printer Machine,Pvc Tube Printing Machine,Polytype Tube Printing Machine
GIG (DONGGUAN) CO., LTD , https://www.decorationmachine.com