Patent GB-1332331-A (GB)
Title: Rotary positive-displacement machine
IPC: F04C2/348
Filed: 1970-09-23
Abstract: 1332331 Rotary positive-displacement machines M L DAVIS and A C SWANSON [trading as GENERAL MANAGEMENT CO] 2 Sept 1970 42061/70 Heading F1F A rotary positive displacement machine (e.g. Figs.1-3) comprised a housing 12, a piston 22 eccentrically mounted in the housing for relative gyratory movement therebetween, at least one sealing vane 26 extending between the housing and piston to define working chambers 30 therebetween, valve means 40 operable to control the flow of working substance to and from said chambers, and at least one of three specific forms of force transfer means arranged to transfer force between the housing 12 and the piston 22 so as to maintain their relative angular alignment substantially  fixed.  Embodiment of Figs.1-3:- This embodiment is intended for operation as an internal or external combustion engine. The piston 22 and its housing 12 are constrained to rotate together in a stationary support 18 at the same angular velocity by force transfer means in the form of gearing. The support 18 has an eccentric hub 58 (axis 16) for supporting the housing 12 and a bore 62 for concentrically receiving piston stub shafts 60 and a rotary or stationary valve tube 100. The aforesaid gearing comprises, Figs.1 and 2, a gear 98 fixed to the housing 12 and a gear 96 fixed to the left piston shaft 60, the gears 96, 98 meshing with gears 92, 94 on an output shaft 97. As shown the valve tube 100 rotates at 1¢ times the speed of the piston and housing, a gear 102 on the tube 100 meshing with a gear 104 on the shaft 97 for this purpose. A partition 106 divides the tube 100 into an inlet passage 108 having a port 112 and an exhaust passage 110 having a port 114. The ports 112, 114 cyclically align with passages 116 in the spokes 68 of the piston, which passages lead to the working chambers 30. A valve tube for each chamber may replace the single valve described, Figs.9 and 11 (not shown). Each chamber 30 is provided with a sparking plug 42 screwed into the housing (as shown) or piston, Fig.10 (not shown). In the former possibility each plug is energized when its contact 138 aligns with a fixed contact 136, while in the latter, energization is controlled by an external distributor. The sealing vanes 26 shown are outwardly urged vanes which slide in slots 20 in the piston. However the vanes may be inwardly urged and slide in the housing or they may be of resilient material such as rubber (especially when using the machine as a pump) and be moulded integrally with the piston or housing, Fig.41 (not shown). Each vane shown is outwardly urged by a pair of pistons 86 loaded by springs 88 and additionally by working fluid communicated thereto through passages 90 from the working chambers 30. Magnetic means or pressure liquid from an auxiliary pump may also be used to urge the vanes. Gas which leaks past the sealing surfaces of the vanes is conducted into the exhaust passage 110 through passages 80 in the vanes, an annular chamber 119 in the piston and ports 118 in the valve tube 100. The surfaces of the piston and housing may be provided with straight or helical cooling fins, air being induced to flow over these surfaces by connecting a casing 126 having an opening 128 to the inlet of a carburettor 122 feeding the inlet passage 108. To increase the compression ratio the inner surface of the housing may be a series of circular arcuate portions of the same radius as the piston, Fig.11 (not shown). Embodiment of Figs.12 and 13 (not shown):- This embodiment is similar to the previous one but the piston and housing are generally triangular, the vanes being located at the corners of the piston and the housing being provided with arcuate recesses at its corners for receiving the vanes. Embodiment of Figs.14-19 (not shown):- This embodiment is intended for operation as a pump, compressor or motor. The piston 22E and its housing 12E are generally triangular. Because of the triangular configuration the surfaces of the piston and housing come into abutment as the housing and piston move relative to each other, the abutment of the surfaces thus constituting the aforesaid force transfer means. However, to maintain a stricter alignment between the piston and housing, through pins 152 fixed between the ends of the housing are rotatable in eccentric bores in the bushes 154 themselves rotatable in bores 156 in the piston. Three different configurations for mounting the piston and housing are described. In the first, Fig.15, (not shown) the housing 12E drives, or is driven by, a belt 178 running in a groove 180 in its periphery. Thus the piston is taken with it around the eccentric valve tube 100E. In the second, Fig.28 (not shown), the housing (12L) is fixed and the valve tube is rotatable around the housing axis, the piston axis being concentric with the valve tube axis. In the third, Fig.29 (not shown), the piston is fixed, the housing and eccentrically mounted tube valve being rotatable. Means for varying the eccentricity are described in general, a preferred example being described with respect to Figs.31 and 32 (not shown). To facilitate sealing the facing peripheral surfaces of the piston and housing may be inclined with respect to their axes, Fig.30 (not shown). Figs.42-44 (not shown) disclose a preferred form of sealing vane construction for the triangular piston. Embodiments of Figs.20-25 and 27 (not shown):- These embodiments are similar to the previous one but the transverse piston configuration is rectangular, diamond-shaped or star-shaped. Embodiment of Fig.45 (not shown):- This embodiment comprises a shaft 230 rotatable about an axis 232. The shaft is provided with a central crank for the piston 20Y and outer cranks for the housing 12Y. The axis 232 is disposed between the central and outer crank axes 24Y, 16Y. The force transfer means is in the form of a pin 234 fixed to the piston 20Y and engaging the surface of a hole 236 in the housing. Figs.37-40 (not shown):- These figures are concerned with alternative valve configurations such as spring-loaded balls and slides.