{TAIL ~ The reducing agent} can circulate between {HEAD ~ the delivery device} and the reactant reservoir thereby, particularly when the dosing valve is closed, preventing the reactant from freezing 
{ TAIL ~ The reducing agent } can circulate between { HEAD ~ the delivery device } and the reactant reservoir thereby , particularly when the dosing valve is closed , preventing the reactant from freezing
TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH