A pump 1, wherein {HEAD ~ the sheet} is in the shape of a substantially spherical or conical cap complementary to the inside surface of the side plate so as to fit against it as closely as possible, with the convex side of this shape facing towards {TAIL ~ the inside} of the chamber 
A pump 1 , wherein { HEAD ~ the sheet } is in the shape of a substantially spherical or conical cap complementary to the inside surface of the side plate so as to fit against it as closely as possible , with the convex side of this shape facing towards { TAIL ~ the inside } of the chamber
OTH OTH OTH OTH OTH 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 OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH