GB580895A - Improvements in or relating to rotary pumps - Google Patents

Abstract

580,895. Rotary pumps. STEVENS, A. H. (Eaton Manufacturing Co.). July 18, 1944, No. 13739. [Class 110 (ii)] A rotary pump of the n and n + 1 lobe type, with rotors 20, 22, has an axially-displaceable end wall 48, secured to rotor 22, which moves when the delivery pressure exceeds a predetermined figure, and overcomes the load of a spring 78. The inner rotor 20, is driven by the outer rotor 22 and rotates on an eccentric portion 40 of the block 28. The chamber 90, at the back of the wall 48, communicates with suction ports 36, 32. The latter, and a similar delivery port 34, are crescent-shaped. An enti-friction washer 80 has a pin 82 as a guide. The spring 78 has a widened end to fit into a cap portion 70 with friction, which prevents rotation of the spring and a disc 76. A driving shaft 46 is driven from an outer shaft 116 through a coupling 100 supported by a bearing 98. A sealing device 104 is provided. An opening 106 allows liquid leaking along the shaft from the pump, to escape to the suction, the liquid acting as a lubricant. The connection between the shaft 46 and the coupling 100 allow sliding of the shaft. A spring 110 presses between the shaft and the coupling which bears against 98. The interior right-hand end of the coupling 100 is polygonal in shape and receives a similarly shaped end of shaft 46. A spigot 112 is provided for aligning the pump when the latter is secured to an engine, or other, block. To prevent relative axial movement between a driving shaft 116 and the coupling 100, a split spring ring 120 is arranged as shown. In a modification, the wall 48 may move relatively to the shaft 46 to which it is coupled by a pin, and slot connection. The pump is of the type described in U.S.A. Specification 1,682,563.