{HEAD ~ Reducing agent} can be conveyed back from {TAIL ~ the delivery device} to the reservoir via a return line 
conveyed back from
{ HEAD ~ Reducing agent } can be conveyed back from { TAIL ~ the delivery device } to the reservoir via a return line
HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH REL REL REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH