JPS57200698A - Self-priming pump - Google Patents

Abstract

PURPOSE:To improve self-priming performance of a pump, by forming a priming port at an upper check valve section so that a hollow space extending from a water intake passage of an impeller located on the downstream side of the check valve section to the upper end of a water discharge passage in an air separating chamber can be filled with water completely. CONSTITUTION:Since a water passage 21 and a water intake passage 10 of an impeller are communicated with each other with removing of a cap 8, water can be charged completely into a space extending from the water intake passage 10 of the impeller located on the downstream side of a check valve section 5 to the upper end of a water discharge passage 12 in an air separating chamber 9, including the water passage 21. After charging of water is completed, the water intake passage 10 and passage 21 are separated from each other by the cap 8 by screwing the cap 8 into place in a water-tight manner. Under such circumstances that water is charged completely in the space extending from the downstream side of the check valve section 5 to the upper end of the water discharge passage 12, i.e., in the state that the self-priming performance of the pump is improved with no air left in the water intake passage 10 of the impeller, the pump can be set into operation with ease and smoothly.