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