METHOD AND APPARATUS FOR SELECTIVELY VARYING THE FLOW RATE OF SERVICE LIQUID THROUGH A TWO STAGE LIQUID RING VACUUM PUMP

摘要

A two stage liquid ring vacuum pump having a selectively variable flow rate of service liquid through a first stage and a second stage. The flow rate through the second stage is reduced by venting service liquid from the second stage prior to normal passage through a discharge port. The vented service liquid is introduced in the first stage to enhance the pumping capacity of the first stage.