GB1501474A - Rotary compressors - Google Patents

Abstract

1501474 Rotary positive-displacement fluidmachines UNISCREW Ltd 16 July 1975 29927/75 Heading F1F In a double-acting compressor, which may be of the sliding-vane type as shown in Fig. 1, a valve 12 when open allows gas in a discharge pipe 8a to pass into one of the working chambers 104a, 104b which is for the time being isolated from both suction ports 5b and a discharge port 7b, this arrangement being said to reduce the power consumption. While the valve 12 is open a check-valve 10 is closed owing to loss of pressure in the pipe 8a. Preferably, the valve 12 opens when the delivery flow-rate is at or near the maximum. A valve 16 may be provided to regulate the inflow of gas in accordance with the pressure in a delivery duct 9. To obtain greater economy, a spring- loaded valve may be disposed in the casing wall portion 4a and arranged to open with the valve 12, so as to reduce the compression ratio in the respective working chamber, Fig. 7 (not shown). The valve 16 may be dispensed with and circumferentially-movable plates, or "shells", 48a, 48b, Fig. 9, be provided to regulate the gas flow at the suction ports according to the discharge pressure. Arrangements generally similar to those shown in Fig. 1 may be comprised in a compressor of the worm and worm-wheel type, Figs. 17-19 (not shown); and, instead of the valve 16, axiallymovable elements (222), Figs. 20-22 (not shown), may be employed to regulate the gas inflow.