{HEAD ~ An oxidizing gas}, preferably pressurized air, is periodically fed into {TAIL ~ the exhaust line} by an oxidizing gas line for cleaning the drain line and the pressure controlling aperture therein by oxidizing the magnesium 
is periodically fed into
{ HEAD ~ An oxidizing gas } , preferably pressurized air , is periodically fed into { TAIL ~ the exhaust line } by an oxidizing gas line for cleaning the drain line and the pressure controlling aperture therein by oxidizing the magnesium
HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH REL REL REL REL TAIL 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