CAPACITY CONTROL DEVICE FOR VARIABLE DISPLACEMENT PISTON PUMP

摘要

PURPOSE:To perform the quick cargo handling work at an early stage and quickly return the flow from the maximum capacity to the minimum capacity when the cargo handling work is completed regardless of the pipeline resistance and pressure loss. CONSTITUTION:A guide path 15 is branched from a delivery pipeline 4 from a pump to a cargo handling circuit 30, and the guide path 15 is provided with a first switching valve 7 and a second switching valve 9 in parallel on a first guide path 5 and a second guide path 6. The first switching valve 7 is operated by a pilot pipeline 8 and displaced by a first set pressure. The second switching valve 9 is operated by a pilot pipeline 10 and displaced by a second set pressure higher than the first set pressure. The outlet sides of the first switching valve 7 and the second switching valve 9 are connected to a continuous selector valve 11, and the outlet side of the continuous selector valve 11 is connected to a control cylinder 3 by a feed path 12. The continuous selector valve 11 is operated by a pilot pipeline 13 and displaced by a third set pressure higher than the first set pressure and lower than the second set pressure.