| 摘要 |
<p>A pump system, particularly suitable for pumping wet mixes and slurries, achieves an output of pumped material substantially free from pulsations or fluctuations by control movement of power pistons (12A, 12B) within power cylinders (10A, 10B). The power pistons (12A, 12B) are connected by piston rods (14A, 14B) to pumping pistons (16A, 16B) which suck material to be pumped in through valves (20A, 20B) and out through valves (22A, 22B) into a delivery pipe (26). A closed loop (32) connects annular chambers (13A, 13B) of the power cylinders (10A, 10B), and a continuously operating pump (P2) feeds the closed loop (32). The power pistons (12A, 12B) on their suction strokes move faster than on the delivery strokes, whereby one or other or both pistons (12A, 12B) are always moving forwards. Control adequate to achieve a smooth delivery of pumped material is achieved by providing sensing valves (PVA1, PVA2, PVB1, PVB2) on each power cylinder (10A, 10B), these valves being arranged to be actuated at different positions of the power piston (12A, 12B) within the cylinder. The sensing valves pass signals to check valves (CV1, CV2) to vent and close the closed loop (32) in response to actuation of the sensing valves and thus to control movement of the power pistons in the cylinders.</p> |
