Ulvac DIS-252 - Shut-Down; Air-Flush Opened Operation

 -22-
4.1.2 Shut-down
①
Be sure to close isolation valve in order to prevent the drawback of debris
attached to inside of vacuum pump into vacuum chamber during operation due to
pressure differential (open leak valve if you use leak valve).
②
Turn off vacuum pump.
Please install an external power switch or protective device (breaker) before
letting vacuum pump operate.
③
Check shut-down of vacuum pump.
Important
Be sure to close isolation valve between vacuum pump and vacuum chamber during pump
shut-down.
If vacuum pump stops during air-flush opened operation, atmospheric air is drawn back from air-flush port to
inside of vacuum pump, and vacuum on chamber side cannot be maintained. Be sure to close isolation valve
between vacuum pump and vacuum chamber to prevent the drawback of debris from vacuum pump into vacuum
chamber before stopping vacuum pump.
When returning air-flush opened operation to air-flush closed operation, operate as per 4.2.3[page 24].
4.2 Air-flush opened operation
This pump is equipped with air-flush port. Before evacuating vapor, read precautions
below completely and be sure to understand the contents.
Purpose of air-flush
Evacuating moisture or humid gas by vacuum pump can cause condensed water to
remain in pump. This remaining water can cause failure of ultimate pressure or
pump. Air-flush opened operation is necessary to exhaust the remaining water
inside. Air-flush opened operation does not only exhaust moisture but also restores
ultimate pressure.
Important
Maintenance interval of this pump is based on clean gas applications The standard differs
when evacuating vapor.
You must shorten maintenance interval (5.2[page 26]) when evacuating vapor since vapor temperature, disposal
volume, disposal frequency and substances in vapor have an influence on pump operation. When evacuating
vapor, pay attention to all WARNING, CAUTION and Important notes (4 [page 19~21]).
※
Vapor disposal volume is max. 25g/day when doing air-flush operation
(ambient temperature 25
℃
, humidity 60%RH).