GB906580A - Apparatus for pumping liquids from containers - Google Patents

Abstract

906,580. Centrifugal pumps. CIBA Ltd. June 20, 1961 [June 23, 1960], No. 22283/61. Class 110 (1). Apparatus for pumping a liquid from a container comprises a vessel within which is enclosed a centrifugal pump, the suction side of which communicates with the interior of the vessel, a pressure pipe extending upwardly from the vessel and communicating with the pressure side of the pump, a suction pipe which opens in the vessel near the bottom thereof, has an elbow bend above the top of the vessel and extends downwardly for delivering liquid from a container to the vessel, and a narrow passage affording communication between the elbow bend and the portion of the pressure pipe extending upwardly from the level of the elbow bend. The centrifugal pump depends from a cover-plate 12 for a container (not shown) for the liquid to be pumped. A motor (not shown) mounted above the cover-plate 12 drives the pump through a shaft 34 passing through a tube 36 which extends beyond the highest level of the liquid in the container. The centrifugal pump is immersed in a vessel 18 which communicates with the interior of the container through a suction pipe 20 having an extension (not shown) which terminates close to the bottom of the container. Initially, the liquid in the suction pipe 20 and a pressure pipe 24 is at the level 52 and the vessel 18 is full. When the pump is started, it draws liquid from the vessel 18 through an inlet 33 and delivers it to the pressure pipe 24. The resultant reduction of pressure at the top of the vessel 18 causes liquid to be drawn out of the container through the suction pipe 20. When this liquid has reached the elbow bend 48, priming of the pump is complete and the liquid in the vessel 18 has fallen to the level 54. Since the outlet opening 44 of the suction pipe 20 is below this level (and advantageously at a higher level than the pump inlet 33), the formation of foam or bubbles due to entrainment of air is prevented. To accelerate the priming, the suction pipe 20 may communicate with the upper part of the vessel 18 through a narrow bore. When the pump is stopped, the liquid in the pressure pipe 24 runs back through the vessel 18 and the suction pipe 20 into the container until it reaches the level of an anti-siphoning conduit 50. Air then passes through the conduit 50 to the suction pipe 20 to break the siphon and the liquid level is stabilized at 52. Specification 864,620 is referred to.