Abstract:
A novel single acting variable displacement vane pump (VDVP) incorporating novel vanes and undervane venting which produce selective regulated pressure-loading of the vanes against the cam surface and more positive tracking in the incoming seal arc and the outgoing or discharge seal arc of the pump rather than uniform pressure balancing of the vanes throughout the 360.degree. cam chamber. The vanes incorporated into the present pumps preferably are sectional two-piece vane assemblies comprising an upper vane section which slidably supports a lower vane section and incorporates a fluid pressurizable cavity between said vane sections which, when pressurized, forces the vane sections in opposite radial directions, and which enables the vane sections to come together and integrate when the cavity is depressurized. The vane cavity is open to the fluid pressure on one side of the vanes while the undervane area of the vane slots, below the vanes, is open to the fluid pressure one the opposite side of the vanes. Thus, in the inlet seal arc area of the pump the vane cavity becomes pressurized to force the vane sections apart and force the upper vane section against the cam surface, and in the outlet or discharge seal arc area of the pump the vane cavity becomes depressurized and the undervane area of each vane slot becomes pressurized, to force the vane sections together and force the upper vane section against the cam surface.
Abstract:
A durable, single action, variable displacement vane pump capable of undervane pumping, components thereof, and pressure balancing method. The pump comprises a cylindrical barstock rotor member having large diameter journal ends and central vane slots uniformly spaced therearound. The vane slots are elongate and have a central vane-supporting portion of maximum depth surrounded at each end by extension portions having depths which decrease axially to the surface of rotor member. The vaned rotor is rotatably supported within a unitary cam member having opposed faces and a circular bore therethrough forming a cam chamber having a continuous interior circular cam surface. The vane slot extensions in the rotor project outwardly beyond the cam chamber. An opposed pair of manifold bearings rotatably support the journal ends of the rotor and overlap the vane slot extensions to admit fluid to expanding vane bucket areas of the rotating vaned rotor and also into the vane slot extensions and undervane areas for pressure balancing purposes. Fluid passages and pressures within the pump are arranged to balance forces acting on various parts to reduce stress, improve sealing, and permit sharing of a fluid pressure source.
Abstract:
A unified fuel pump assembly combines a vane-type pump and a booster stage for the inlet of the vane-type pump, in a unitary structure to substantially reduce "windage" losses caused by relatively moving parts. The unified structure also includes an electric motor subassembly to provide motive power, and a liquid ring pump, which helps to process air bubbles through the fuel pump, is coupled to the electric motor rotor to further avoid "windage" losses. The vane type pump relies on the use of a central shaft capable of having a substantially uniform and relatively large diameter from end to end.
Abstract:
A pumping system has a main pumping unit (14) and a backup pumping unit (16) mounted in a common housing (4) and adapted to be driven by a drive member (44). The main pumping unit is connected to the drive member by a main drive coupling (68) which incorporates a reduced shear section (76) designed to fail upon a jamming or seizure of the main pumping unit. A backup drive coupling (78) connected to the backup pumping unit is adapted to be axially displaced and threadably connected to the drive member after stoppage of the main pumping unit. An actuation device (18) functions to axially displace the backup drive coupling to establish threaded engagement. When the backup drive coupling is engaged with the drive member, the backup pumping unit will provide flow.
Abstract:
A pump comprising a durable rotor member having large diameter journal ends at each side of a central vane section comprising vane slots having well areas which slidably-engage a mating vane element. The present vane pumps comprise novel cylindrical floating ring seal elements having a support body which continuously seals the face of the cam member, and have a movable inner ring assembly which becomes pressure-loaded against the rotor journals during use, to minimize or limit axial pressure leakage while balancing or minimizing bearing load.
Abstract:
A variable displacement vaned fuel pump (10) is suitable for inclusion in a fixed displacement fuel control system for a gas turbine engine. The pump includes two track elements (34,36) having cam surfaces (42) which engage cam followers (44) on a cam actuation ring (40). A link (66) having a predetermined spring load maintains the track elements in their radially inner maximum displacement positions until the vane force and pressure forces drive the track elements radially outwardly, moving the actuation ring against its spring load. Displacement of the pump is reduced in the radially outward positions of the track elements which reduces the required bypass flow to hold a head constant across a fuel metering valve and attendant fuel heating.
Abstract:
A vane pump (2), with undervane pumping capability, has a housing (4,14) within which a cam ring (16) is mounted. The cam ring has a cam surface which defines a pumping cavity and which includes two diametrically opposed inlet arcs (48, 50), two diametrically opposed discharge arcs (38, 40) and seal arcs (56, 58, 60, 62) disposed between the inlet arcs and discharge arcs. A rotor (12), mounted for rotation within the housing, carries a plurality of spokes (22). Mounted upon the spokes for radially outward and inward movement are channel-shaped vanes (28) having arcuate tips (46) for engaging the cam surface. Variable volume chambers (94), which provide undervane pumping, are formed between the radially outer ends of the spokes and the vanes. The variable volume chambers communicate with intervane volumes (93) through grooves (86) on the spokes. The vane tips engage seal arcs along a line of contact (76) selected to insure that the vanes are pressure balanced.
Abstract:
A variable displacement vane pump comprising a durable rotor member having journal ends at each side of a larger diameter central vane section comprising vane slots having well areas which slidably-engage a mating vane element. The present vane pump comprise novel cylindrical ring seal elements having a unitary body which seal the faces of the cam member, and which overlap the central vane section and vane slot extensions. The seal elements include first fuel inlet passages in the inlet arc segment thereof, and fuel discharge passages in the discharge arc thereof, both of said passages being open to the vane slot extensions and to the cam chamber for the continuous supply and pressure discharge of fuel.
Abstract:
A variable displacement vane pump comprising a durable rotor member having journal ends at each side of a larger diameter central vane section comprising vane slots having well areas which slidably-engage a mating vane element. The present vane pump comprises an outer cylindrical cam enclosure or spacer loaded against ring seal elements to support the faces of the seal elements closely spaced from the cam faces and reduce the actuation force required for adjustment of the displacement capacity of the pump. The cam faces include a biased segment seal in the high pressure discharge arc area. The seal elements include first fuel inlet passages in the inlet arc segment thereof, and fuel discharge passages in the discharge arc segment thereof, both of said passages being open to the vane slot extensions and to the cam chamber for the continuous supply and pressure discharge of fuel.
Abstract:
A shaft seal assembly 10 for a high speed centrifugal pump has a primary seal (30) and a secondary seal (32). During normal operation the primary seal has its nose (38) in firm engagement with a seal face (28) and the secondary seal has its nose (42) in light engagement with the seal face. Upon failure of the primary seal, the nose of the secondary seal is urged into firm engagement with the seal face. An orifice (58) in the nose of the secondary seal allows for controlled leakage which indicates primary seal failure.