Explosion of cryopumps during restoration

Case example

After the cryopump stops for any reason such as a failure, electric outage, or excessive overload, it may explode on the atmosphere side of the pump if a gas is exhausted with the hydraulic rotary pump when restarting.

Cause

If the cryopump stops for any reason, the temperature in the pump increases and absorbed gases such as hydrogen and oxygen are released. If such gases are exhausted all at once, an explosion occurs on the atmosphere side.

Countermeasures

Make sure to “restart while introducing nitrogen”.