GB895914A - Improvements in or relating to self-priming pump systems - Google Patents

Abstract

895,914. Centrifugal pumps. ATKINSON CO., GUY F. July 24, 1959, No. 25575/59. Class 110 (1). A self-priming pumping system comprises a closed suction well 10 holding priming liquid, an inlet connection 12 at the top of the well, a pump 11 in the well, an accumulating chamber 60 above the well, a discharge pipe 63 communicating with the top of the chamber, means such as the check valve 62 to prevent back flow from the pipe to the chamber, ports 36 in the conduit communicating with the well and a valve 40 in a housing 30 actuated by pump discharge pressure to close the port and to pass discharge from the pump to the chamber and on cessation of discharge to pass a return flow from the chamber through the port to the well to reprime the pump and passing air from the well to the chamber so that the discharge of liquid in the next pumping cycle will force the air from the chamber to the discharge pipe. Upon starting the pump, the suction well 10 and the accumulating chamber 60 normally contain liquid and air respectively and the valve member 40 is on its seating, Fig. 6. The pump discharge flows from passages 21, through holes 47 and 51 of the valve member and the liquid pressure moves the valve to its uppermost position, Fig. 3. Ports 34, which communicate with the discharge conduit are opened, the ports 36 which communicate with the well and the discharge flows through the body of the valve and passageways 35, discharge conduit 25, into the chamber 60. When the pressure in the chamber 60 exceeds the static head in the pipe 63, the check-valve 62 opens and the air in the chamber is discharged through the pipe. As the liquid level falls in the well, the pump starts to run dry and the pressure in the chamber 60 falls, the check-valve 62 closes and the valve 40 begins to fall until the liquid within it is vented through openings 47 and 52 into the ports 36 to the suction well. This allows the valve 40 to drop rapidly to its lowermost position, Fig. 6, thereby permitting free flow of liquid through conduit 25 and ports 36 from the chamber 60 to the well 10. Air from the upper part of the well flows through pipe 65 and check-valve 66 to replace the liquid in the chamber. This cycle is repeated until the air is exhausted from the suction system when a continuous flow of liquid is pumped into the chamber 60, through the check-valve 62 and through the discharge pipe 63.