How to detect the tightness of the refrigeration equipment system

How to detect the tightness of the refrigeration equipment system

Keep the refrigeration equipment under a proper vacuum for a certain period of time, and observe whether the air infiltrates the system from the reading of the vacuum pressure gauge to check the sealing performance of the system. This experiment must be carried out for refrigeration systems whose evaporative pressure gauge is close to or below atmospheric pressure. Vacuum experiment usually has the following two methods, let's learn about it with the editor of okmarts.com!

How to detect the tightness of the refrigeration equipment system

　　 1. Use an external mechanical vacuum pump for vacuum leak testing. This method is generally used at small cold storage equipment. The specific steps are as follows:

　　 1. Unscrew the fine thread screw plug of the channel for the suction stop valve counterclockwise, and turn the suction stop valve stem clockwise for several turns to make the suction stop valve in a three-way state.

　　2. Connect the vacuum pump and the multi-purpose 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 valves in the system (including solenoid valves and manual valves, etc.);

　　4. Turn on the power of the vacuum pump and vacuum the system until the reading of the vacuum pressure gauge reaches -0.1MPa. After a suitable time, turn the suction stop valve stem counterclockwise to exit and tighten;

　　5. Keep it for 18-24h, if the vacuum degree does not change, the refrigeration system vacuum experiment is considered qualified.

　　 2. Use the compressor in the system for self-evacuation experiment. For larger refrigeration systems, this method is usually used for vacuum experiment. 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 to the end, so that the system loses the circulation channel at the compressor exhaust port.

　　 2. Unscrew the fine thread screw plug of the multi-purpose channel of the exhaust stop valve counterclockwise to make the exhaust port communicate with the atmosphere.

　　 3. Open all valves in the system.

　　 4. Short-circuit the contacts of the low-voltage relay and temporarily remove the protection function (must be restored afterwards).

　　5. Start the compressor to discharge the air in the system into the atmosphere (the suction valve of the compressor should be opened slowly to prevent the gas in the system from being too late to discharge, resulting in excessive discharge pressure and high pressure protection, etc.).

　　6. ​​Observe the vacuum gauge on the low-pressure side until the vacuum pressure gauge reaches -0.1MPa. After a suitable time, rotate the exhaust shut-off valve stem and tighten it.

　　7, keep for 18-24h, if there is no change in the vacuum degree, it is qualified.

　　 3. Pay attention to during the test:

　　 1. When self-evacuating the pressure lubrication compressor refrigeration system, the contact of the oil pressure relay should be temporarily forcibly connected.

　　2. The time for self-evacuation cannot be too long, otherwise the compressor's operating parts will be prone to greater wear and metal fatigue if working at higher temperatures for a long time.

　　3. In the self-pumping test, connect a hose to the exhaust port, insert the other end of the hose into the oil, and observe the overflow of air bubbles on the oil surface. If there is no bubble overflow for a long time, the vacuum can be stopped, and the vacuum degree is qualified after 24h. If the air bubble does not stop for a long time, first close the compressor suction valve and check whether the compressor is leaking. If there are no air bubbles in the oil, it means that the compressor is not leaking, and there is leakage in other parts of the system; if the air bubbles continue to occur , This is often caused by the lack of tight seals.