The 5 micron filter 74 is backwashed by {HEAD ~ means} of {TAIL ~ pump} 58 
of
The 5 micron filter 74 is backwashed by { HEAD ~ means } of { TAIL ~ pump } 58
OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL OTH