One end of the tube 45 is in communication with one end of the tube 46, the other end of the tube 46 is in communication with one end of {HEAD ~ the tube} 48, and the other end of the tube 48 is in {TAIL ~ communication} with one end of the tube 50 
One end of the tube 45 is in communication with one end of the tube 46 , the other end of the tube 46 is in communication with one end of { HEAD ~ the tube } 48 , and the other end of the tube 48 is in { TAIL ~ communication } with one end of the tube 50
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH