A reciprocating compressor is provided with a discharge valve having an
area inward of a valve seat which is greater than the area of the
discharge port. The valve seat also has a distinct shape compared to the
valve port in preferred embodiments. The increased area within the valve
seat results in an increased force tending to open the valve from a
compressed fluid. On the other hand, since the valve port remains
relatively small, the flow losses are not significantly increased.