GB566420A - Improvements in or relating to rotary pumps - Google Patents

Abstract

566,420. Rotary compressors. CURTIS PUMP CO. June 25, 1943, No. 10308. Convention date, Feb. 13, 1943. [Class 110 (ii)] A rotary sliding-vane compressor has means subjected to the discharge pressure for introducing lubricating oil to the working chamber at a point between the inlet and outlet ports, under a pressure which is between the suction and discharge pressures. The inner sides of the vanes 32 are acted upon by oil under pressure, the pressure in a chamber 38, opposite the discharge port 12, being higher than that in a chamber 41 under the remainder of the vanes. A discharge pipe 13 leads to a filter 14 containing a number of screens 15. Cleaned air passes to a reservoir 17 and oil, separated out, is led through a pipe 18 with coils 19, cooled by a fan 20, driven by a motor 21 and returned to the compressor. The oil absorbs heat of compression in the working chamber to secure greater efficiency. A shaft 24 is coupled to a rotor 29 and may be driven by the motor 21. Oil from the pipe 18 enters a bore 36 in a pin 35 and passes through ducts 37 to the chamber 38 in the rotor bore. The pin 35 is slightly smaller than the rotor bore 30 and allows oil to flow over walls 39 into a chamber 41 where its pressure is less than that in the chamber 38. The oil flows from the chamber 41 through a radial hole 42, a pipe 46 containing a restriction 46a, to a hole 49 which communicates by way of ducts 50, with the working chamber 26 and minimises work lost due to liberation of dissolved air from the oil, due to the pressure drop, the ducts 50 leading to a part of the working chamber that is under pressure.