The invention reduces pulsation in the back pressure chamber and also reduces pumping losses caused by {HEAD ~ fluid} moving into and out of {TAIL ~ the back pressure chamber} through the hole 
out of
The invention reduces pulsation in the back pressure chamber and also reduces pumping losses caused by { HEAD ~ fluid } moving into and out of { TAIL ~ the back pressure chamber } through the hole
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD OTH OTH OTH REL REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH