Common cryogenic pump suction system failure analysis and troubleshooting: Cryogenic vacuum pump system failure is the most basic phenomenon of the pressure in the vacuum system. Cause the system pressure increases because: First, the vacuum system leaks; the second is the work of cryogenic pump failure. Leakage of vacuum system Leak detection of vacuum container and cryogenic pump can be performed respectively by helium mass spectrometer leak detector. If leak is not found, the cryogenic pump malfunction must be ruled out one by one according to the following conditions. First, the pressure increase in the vacuum container (two cold array temperature is lower than 20K) 1, the vacuum system or cryogenic pump itself has a leak, you can leak through a vacuum system; b. Check the safety valve is reset ; C cryogenic pump mechanical leak to exclude. 2, There is He, Ne, H2 and other non-condensable gas in the pumped container (due to the saturation of the adsorption plate), the pump can be regenerated to solve this fault. 3, the fixed two cold array screws loose, so that suction suction surface temperature is higher than 20K (under normal circumstances, this possibility is less), to deal with such failures can pump back to room temperature, check one or two Level cold array assembly situation. Second, the pressure in the vacuum container (low temperature surface temperature of less than 20K) 1, two cold array adsorber adsorption saturation, this time need to pump regeneration. 2, the exhaust load is too high, you can shield or reduce the radiation surface temperature to solve such failures. Third, the temperature of the cryogenic pump two cold array less than 20K, or take a long time to reach 20K. 1, the cooling capacity of the refrigerator worse, to solve such failure methods a. Check the compressor supply pressure is normal, such as low mechanical pressure gas; b. The pump regeneration; c. Cooler contaminated, or a , Two seal ring wear. 2, the compressor pressure is low, then you need to their qi. 3, the vacuum system or cryogenic pump itself has a leak, this time requires a. Vacuum system for leak detection; b. Pump leak, safety valve is reset. 4, there are more inside the cryogenic pump He, Ne, H2 and other non-condensable gas (partial pressure higher), then wash with N2 gas or regeneration can be. 5, the compressor is not working properly, then need to overhaul the compressor. Fourth, cryogenic pump issued a rumble, then generally 50Hz / 60Hz switch position wrong, as long as the solution to open the switch on the correct location.
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