GB1134479A - Self priming system for horizontal pumps - Google Patents

Abstract

1,134,479. Self-priming centrifugal pumps. HUDSON ENGINEERING CO. June 9, 1967 [June 10, 1966; April 10, 1967], No.26689/67. Heading F1C. A self-priming pump 20, Fig. 1, having a horizontal inlet 6 draws liquid from a suction line 40 via a suction well 4 having a cavity which is at least in part below the inlet 6 and is connected at its upper part to the suction line 40. A suction pipe 5 extending from the inlet 6 towards the bottom of the suction well 4 may, as shown, be curved upwardly so that the lower inner surface of the upper portion is approximately level with the upper inner surface of the inlet 6, and an air bleed aperture may be provided in the upper portion. The pump discharge through a discharge column 8 containing a repriming valve assembly 30. During normal flow, the depression occurring at the throat of a Venturi in the lower part of the inner casing 34, Fig. 2, of the assembly 30 and communicated via tubes 35 to cylinders 36, maintains poppet valves 31 closed. If the pump loses its prime, the valves 31 are opened by springs 37 and liquid in the discharge column 8 and assembly 30 returns via the valves 31 and a drain pipe 9 to the suction well 4. The air displaced from the suction well 4 by the returned liquid passes via a pipe 10 and a non-return valve 11 to the discharge column 8 at a point upstream of the main non-return valve 12. When the returned liquid has risen through the suction pipe 5 into the inlet 6, it is passed by the pump 20 into the discharge column 8. The resultant flow through the Venturi within the valve assembly 30 causes the valves 31 to close. The non-return valve 11 closes, and the air which has entered the discharge column 8 is forced through the non-return valve 12 into the discharge line 42. The reduction of pressure in the suction well 4 due to the removal of the liquid from the suction well draws liquid up through the suction line. The cycle repeats until priming is completed. In a modification, Fig. 3 (not shown), a pipe (63) is provided to pass entrapped air from the impeller inlet casing (64) to the suction well (4) or to the upper end of the discharge column (8).