Abstract: An economical valve assembly for mounting resilient metal leaf valves for the cylinder of a reciprocating compressor. A valve plate with suction and discharge ports has a discharge leaf or flapper valve with a mounting portion secured thereto by a pair of rivets which have elongated body portions that extend inwardly from the valve plate. The suction valve has a mounting portion with apertures through which the projecting portions of the discharge valve fasteners extend. The elongated portions of the fastener bodies are received in holes in the cylinder block, positioning the valve plate and valves on the block. Pressure on the discharge valve is established by the rivets while pressure on the suction valve is established by the valve plate mounting. Sufficient pressure to achieve a satisfactory seal is applied independently to the mounting portion of each of the leaf valves without causing distortion which might result in failure of the valve to seat properly.

Abstract: The present invention comprises a small, precise measuring pump provided with a germ barrier that is specifically designed for intravenous feeding devices in which the fluid being pumped is positively displaced; in which there is no rubbing contact of one member with another which would be destructive of blood being pumped; the pumping chambers are small, so that they will hold as little fluid as possible; and in which the valves are actuated by gravity and which are tight-sealing when the pump is in a substantially vertical position, but which, when the pump is tipped on its side, are open to permit the preliminary filling of the pump with the fluid to be pumped.

Abstract: A compact pumping system especially useful in liquid chromatography wherein comprising a liquid path which is fully flushed on each stroke of a pump, a pump which provides substantially pulse-free flow, a pressure-sensor integrated into said flow path and operably connected to the control circuit of a bifilar stepping motor. This circuit is so designed that the driving current applied to the motor is only that required to pump the liquid. The avoiding of heat associated with a greater current is particularly important in forming a compact package of motor and pump for use in liquid chromatography.