The chamber is sealed upon purging of {TAIL ~ all the air} and is maintained in a pressurized state for a period of {HEAD ~ time} 
The chamber is sealed upon purging of { TAIL ~ all the air } and is maintained in a pressurized state for a period of { HEAD ~ time }
OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD