MEANS FOR VARYING LOW LOSS OF FLOW FROM POSITIVEE DISPLACEMENT PUMPS BY PERIODIC FLOW SHUTS

摘要

The flow of fluid from a constant output positive displacement pump entering an outlet line directed to a consumer may be varied by periodically interrupting this flow and directing the flow instead into a zero pressure pump reservoir. This interruption is accomplished by a rotary shutter which periodically and alternately opens and closes the line to the reservoir. The line from the pump flows into two nozzles opening into opposite sides of the rotary shutter and directed toward one another. The rotary shutter comprises a shaft with two raised ribs thereon positioned to simultaneously open or close both of the nozzles, thus hydrostatically balancing the shaft. The edges of the raised ribs have cutting angles thereon for milling the opening of the nozzles during operation to produce an optimum gap between the rotary shutter and the nozzles. Only when the nozzles are closed is the flow directed into the outlet line to the consumer. An improved shape for the nozzle openings with respect to the rotary shutter edge is also disclosed.