The control provides quick response and actuates {HEAD ~ the level control} to effect accurate maintenance of the required liquid level in {TAIL ~ an air pressure control system} or, for example, a variable resistance control in an electrical control system 
in
The control provides quick response and actuates { HEAD ~ the level control } to effect accurate maintenance of the required liquid level in { TAIL ~ an air pressure control system } or , for example , a variable resistance control in an electrical control system
OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH