In {HEAD ~ still another form} of {TAIL ~ the invention}, the heat exchanger forms an essentially closed reservoir so that the exhaust pipe does not come in contact with the fluid flowing therethrough 
of
In { HEAD ~ still another form } of { TAIL ~ the invention } , the heat exchanger forms an essentially closed reservoir so that the exhaust pipe does not come in contact with the fluid flowing therethrough
OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL 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 OTH OTH OTH