ULVAC CRYOGENICS INC｜[Basic Knowledge about Cryopumps 6 ]

Seven key points for maintenance

To maintain good performance of a cryopump;
Although our cryopumps are designed to provide high reliability and long-time continuous operation, it is necessary to perform maintenance works on a regular basis.
It is important to perform daily checks to prevent failure.

Seven key points
[Cryopump Assembly]

1.	Cryopanel temperature (Check temperature of cryopanels)	→	Below 20K: Normal Above 20K: Abnormal
2.	Shield temperature (Check the electromotive force of CA thermocouple)	→	-5.5mV～-7.0mV: Normal -5.5mV以上: Abnormal (When ambient temperature is 20°C)
3.	Cryopump sound, vibration (hearing, bodily sensation)	→	Periodic: Normal Irregular: Abnormal

 

[Compressor Unit]

4.	Helium charge pressure while a compressor is in operation (Read SUPPLY pressure gauge of a compressor unit)	→	Charge pressures vary depending on the models. Refer to compressor instruction manual for the appropriate values.
5.	Elapsed time meter(E.T.M) (Check the total operation time on ETM of a compressor unit)	→	Maintenance intervals vary depending on the models. Refer to compressor instruction manual and replace adsorbers, coldhead seals or bearings.
6.	Sound or vibration of a compressor unit while in operation. (by hearing or sensing bodily)
7.	Cooling water flow rate, inlet temperature (with water-cooled types)	→	Refer to compressor unit instruction manual.