GB633222A - Rotary pumps for liquefied gases - Google Patents

Abstract

633,222. Centrifugal pumps. LINDE AIR PRODUCTS CO. Jan. 21, 1948, No. 1899. Convention date, Feb. 1, 1947. [Class 110(i)] In a rotary pump comprising an impeller operating in an annular channel, fluid pressure within a portion of the channel is used for balancing the net force on the impeller produced during the pumping action by an increasing pressure gradient in the channel from the inlet to the outlet end thereof. In a two-stage embodiment, which is used for pumping low temperature liquefied gases, impellers 14, 15 are slidably connected to a shaft 19 by splines 20. The hub 18 of impeller 15 is preferably closed by a plug 40, and is journalled in a bearing 28. The impellers bear against thrust bearings 23, 24. A space around the hub 18 is divided by partitions 34 into two chambers 35, 36. Chamber 35 communicates with the hub region of impeller 15 by way of a hole 37. Chamber 36 communicates by way of a passage 38<1> and passages 38<2>, 38<3> (not shown with the second-stage chamber 12 near its inlet. The radial thrust exerted on the shaft 19 by the pumping action is balanced by a radial thrust caused by the difference of pressure between chambers 35 and 36. A chamber 41 is held at a low pressure, as by means of a passage 42 communicating with chamber 36. so as partially to relieve end thrust on the thrust bearing 24. The invention is applicable to a single-stage pump.