GB1166225A - Rotary Pumps. - Google Patents

Abstract

1,166,225. Centrifugal pumps. AMERICAN OPTICAL CORP. Feb. 9, 1968 [March 22, 1967], No. 6642/68. Heading F1C. A rotary pump comprises a housing divided by an annular partition into upper and lower chambers, the partition being integral with or in circumferential contact with the inner surface of the lower chamber so as to provide an overflow passage having a smaller radius than the lower chamber, an intake impeller in the lower chamber and a discharge impeller in the upper chamber, at least one intake pipe communicating with the lower chamber and projecting into it, and a discharge port communicating with the upper chamber. The housing comprises sections 22, 23, 24, Fig. 3, and a cover plate 19, held together by tie rods (not shown). The electric driving motor (not shown) is bolted to the coverplate 19 with its shaft 33 connected to a stub shaft 32. Impellers 30, 31 are clamped against a shoulder 32' on the stub shaft 32 by means of a clamping disc 34 and screws 36. Impeller 30 comprises a disc 49 formed with holes 50 and carrying depending vanes 47. Impeller 31 comprises discs 53, 54, 55 each formed with holes 56, Figs. 3 and 5, and notched at 58 to form vanes 59. Intake pipes 38 project into the housing between the discs 53, 54, 55, and are connected to separate sources of liquid. Any unused intake pipes 38 may be sealed off or allowed to remain open and suck air into the pump. The pump can be initially primed through the discharge connection 64. The impeller 31 rotates the liquid present in the base of the pump to form a vortex. The ends of the intake pipes 38 are below the free inner surface of the vortex, and the high velocity of the liquid passing over them creates a partial vacuum to draw liquid from any vessel to which any intake pipe is connected. The liquid drawn into the pump rises above an overflow partition 44 and is discharged through the discharge connection 64 by the impeller 30. Air drawn into the pump leaves through impeller holes 56 and 50, space 66 and overflow port 65. If there is only intermittent liquid intake, the stepped lower surface of the partition 44 retains sufficient to keep the pump primed, this liquid returning to the lower part of the pump casing through holes 57 in the disc 53. If the discharge connection 64 is blocked, any overflow from the pump housing can leave through the overflow port 65. A normally closed sludge drain 60 permits the pump housing to be cleaned and drained. In a simplified embodiment, Figs. 10-12 (not shown), the lower impeller (31a) comprises a single disc carrying dependent vanes (69) each formed with a slot (70) to clean the intake pipes (38).