| 摘要 |
<p>PURPOSE:To increase the cooling efficiency by drilling a shaft hole for introducing cooling water onto a plunger and freely fitting a fixed rod into said shaft hole, thus accelerating flow of water into said shaft hole. CONSTITUTION:In a plunger 5 of a plunger pump, a shaft hole 16 which is opened on the top edge surface of said plunger 5 at one edge and extends to the vicinity of the part corresponding to a shaft seal part 8 at the other edge part is formed. A fixed rod 17 is projected from a fixed member set opposite to the top edge surface of the plunger 5, namely the top wall of the valve box 10d of a water suction valve 10, and the top edge side of the fixed rod 17 is freely fitted into the shaft hole 16 on the plugner 5. Therefore, when the plunger 5 retreats in A direction, the fluid in a pump chamber 4 flows to the bottom of the shaft hole 16 through a slit 18. While, when the plunger 5 advances in B direction, fluid is pushed into the pump chamber 4 through the slit 18, and the frictional heat generated on a packing 8a is removed efficiently.</p> |
