Discharge valve 12 can be moved by an adjustment mechanism 15 in such a way that either of the apertures 13 or 14 is positioned in {HEAD ~ the flow passageway} to {TAIL ~ the outlet} of exhaust line 11 
to
Discharge valve 12 can be moved by an adjustment mechanism 15 in such a way that either of the apertures 13 or 14 is positioned in { HEAD ~ the flow passageway } to { TAIL ~ the outlet } of exhaust line 11
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 HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH