Regeneration of cryogenic vacuum pump

Unlike other gas transfer pumps, the cryogenic pump will be saturated in the gas capture process, so it is necessary to release the adsorbed captured gas to restore the capture capacity, which is called the regeneration process.
The regeneration of cryogenic vacuum pump actually includes partial regeneration (only releasing the gas adsorbed by the secondary cold plate) and full regeneration (releasing all the gas adsorbed by the cold plate). What this paper wants to understand is several ways of all regeneration of cryogenic pump.
1、 Natural temperature rise method. After turning off the refrigerator, use the heat of the pump wall to slowly heat up the vacuum pump. When the pressure in the vacuum pump rises to the effect of convective heat transfer, the heating rate accelerates and then reaches a stable heating value.
2、 Outgassing temperature rise method. After turning off the refrigerator, open the vent valve and put in clean and dry air to quickly heat up the cold plate of the low-temperature vacuum pump.
3、 Electric heating method. An electric heater is installed on the primary and secondary cold plate of the low-temperature vacuum pump. During regeneration, the low-temperature plate is heated rapidly by electric heating to shorten the regeneration time.
Among these regeneration methods, natural temperature rise is applicable to the vacuum system that removes a small amount of gas and is not continuous and long-term exhaust, which generally takes 5 ~ 6 hours. In applications requiring rapid regeneration, the latter two regeneration methods need to be adopted.
In the regeneration process of cryogenic vacuum pump, the released gas needs to be pumped out in time to prevent possible damage to the pump body or the glass tube shell of vacuum gauge, or even explosion. Because when the temperature rises to a certain temperature, the desorption speed of permanent gas is very fast, and the pressure in the pump body can rise to more than one atmospheric pressure within a few minutes.

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