摘要 |
A volumetric machine comprises a cylindrical screw meshing with a pinion-wheel, a low pressure port near one end of the screw, a high pressure port near the other end of the screw, and a control slide axially movable in the bore of a housing in which the screw is rotatable. In one condition, including a series of positions, the slide more or less broadens the high pressure port and thus controls the volumetric ratio of the machine, but covers any threads of the screw which are meshing with the pinion-wheel. In another condition, the slide closes the high pressure port except a stationary port but uncovers some of the threads meshing with the screw, such as to establish a part load with a predetermined volumetric ratio.
|