| 摘要 |
931,092. Rotary pumps and motors. DOWTY ROTOL Ltd. Jan. 1, 1960 [Oct. 3, 1958], No. 31698/58. Class 110 (2). An hydraulic system comprises a gear pump 11 which is arranged in series with a metering device 16 and provided with a by-pass conduit 17, 26 controlled by a slide valve 21 responsive to the pressure differential across a diaphragm 27 interconnected in the circuit as shown. The control 17 may incorporate an orifice 17a dimensioned so that the pressure drop thereacross approximates to the pressure loss due to turbulence in the metering device. The pump may have a greater capacity than the meter 16 and be driven at the same speed thereas or it may be driven faster than the member 16 and have the same or a lesser capacity. The above embodiments may be modified whereby the member 11 constitutes a motor which drives the meter 16 and is arranged upstream or downstream thereof, the valve 20 being arranged to act in the opposite sense to that described above. |
