703,534. Liquid-ring pumps. SIEMEN, O., and HINSCH, J. July 9, 1952 [July 9, 1951], No. 17292/52. Class 110 (1) In a multi-stage liquid-ring pump for the common delivery of gases and liquid, the gases are admitted to the first stage and the liquid is admitted to the second stage. Thus, in the pump shown, air and vapours from a condenser enters the first stage 2 by way of a suction branch 10 and suction port 6, while condensate and cooling water enter the second stage 3 by way of a suction branch 11 and a suction port 13. In a modification, the branch 11 is connected to an interstage space 4. In order to reduce noise, a small amount of air may be supplied to the interstage space through a breather valve. The pump may have three stages. The condenser is situated at a height above the pump which corresponds to the increase in head which occurs between the suction sides of the first and second stages.