When {HEAD ~ the parameter} to be sensed reaches {TAIL ~ a predetermined value} or configuration, the switching apparatus may, by means of electronic signals, cause the first valve apparatus to close 
When { HEAD ~ the parameter } to be sensed reaches { TAIL ~ a predetermined value } or configuration , the switching apparatus may , by means of electronic signals , cause the first valve apparatus to close
OTH HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH