Safety device for avoiding entrapment at {HEAD ~ a water reservoir drain} having {TAIL ~ a secondary blowing pump} 
having
Safety device for avoiding entrapment at { HEAD ~ a water reservoir drain } having { TAIL ~ a secondary blowing pump }
OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL