Rotary positive displacement device

Abstract

A rotary positive displacement device comprises a housing having low and high pressure ports; first and second complementary members each having an outer surface, an axial surface and a shaft. The axial surfaces intermesh to form at least two chambers therebetween having a variable volume as each chamber orbits about a rotational axis of the first member. At least one repositionable gate comprising an aperture is selectively aligned with the high or low pressure ports to form at least one of an adjustable high pressure or low pressure opening. The high or low pressure opening extends between the first and second members and the corresponding high or low pressure port. A lower edge of the high pressure opening is positioned along an outer diameter of the outer surface of the second rotor and between the first rotor shaft and the second rotor shaft.

What is claimed is: 
     
         1 . A rotary positive displacement device, comprising:
 a housing having a low pressure port and a high pressure port;   first and second complementary members, wherein the first complementary member is a first rotor, the first rotor comprising a first body connected to a first shaft that is rotatable about a first rotational axis, the first body comprising an outer surface and an axial surface, the second complementary member comprising a second body connected to a second shaft, the second body comprising an outer surface and an axial surface, and   at least one repositionable gate comprising a sealing surface and an aperture, the aperture of the repositionable gate being selectively aligned with one of the high pressure port or the low pressure port of the housing to comprise at least one of an adjustable high pressure opening and an adjustable low pressure opening between the first and second bodies and the high pressure or low pressure port, and   wherein the axial surfaces of the first and second bodies intermesh with one another to form at least two chambers therebetween when at least the first rotor is rotating via the first shaft, each chamber of the at least two chambers having a variable volume as each chamber orbits around the first rotational axis, and   wherein the at least one of the adjustable high pressure opening and adjustable low pressure opening is configured to selectively communicate with one or more of the at least two chambers as the at least two chambers orbit around the first rotational axis.   
     
     
         2 . The device of  claim 1 , wherein the outer surfaces of the first and second bodies are both selected from a group comprising: frusto-spherical, frusto-cylindrical, frusto-conical, swept, planar. 
     
     
         3 . The device of  claim 1  wherein the adjustable high pressure opening or adjustable low pressure opening further comprises a circumferential conduit in the housing and a stationary aperture in the housing, the circumferential conduit and the stationary aperture in the housing both in fluid communication with one of the corresponding high pressure port or the low pressure port and the aperture in the at least one repositionable gate so as to increase a flow area located between the high pressure port or low pressure port and the at least two chambers. 
     
     
         4 . The device of  claim 1  wherein the first and second shafts are co-linear. 
     
     
         5 . The device of  claim 1  wherein the second complementary member is a stator. 
     
     
         6 . The device of  claim 1  wherein the second body is a second rotor and the second shaft is rotatable about a second rotational axis, and the first rotational axis intersects the second rotational axis, and wherein each of the axial surfaces of the first and second bodies of the first and second rotors comprises at least one teardrop surface and at least one engagement surface, the at least one teardrop surface and the at least one engagement surface together defining at least one lobe and a corresponding valley, and
 wherein each outer surface of the first and second bodies of the first and second rotors is frusto-spherical, and 
 wherein the axial surfaces of the first and second rotors are each configured to intermesh with one another such that the at least two chambers formed therebetween are separated by the axial surfaces of the first and second rotors, and 
 wherein the at least one of the adjustable high pressure opening and low pressure opening is positioned along the outer surface of the first rotor and adjacent to at least one side of the valley of the first rotor. 
 
     
     
         7 . The device of  claim 6 , wherein the at least one engagement surface of the axial surface of at least one rotor of the first and second rotors includes a radial recess extending along the at least one engagement surface, the radial recess extending to an outer diameter of the at least one rotor. 
     
     
         8 . The device of  claim 1  wherein the at least one repositionable gate is sandwiched between the first rotor and the housing, and wherein the aperture of the repositionable gate may be selectively circumferentially positioned relative to the position of the at least two chambers. 
     
     
         9 . The device of  claim 1 , wherein the at least one repositionable gate is selectively circumferentially positioned so as to align the gate aperture of the at least one repositionable gate with each chamber of the at least two chambers such that each chamber will pass the corresponding gate aperture at a selected volume ratio and volumetric capacity of each chamber of the at least two chambers. 
     
     
         10 . The device of  claim 9 , further comprising a stationary aperture in the housing having stationary leading and trailing edges, and wherein the aperture in the at least one repositionable gate comprises adjustable leading and trailing edges, and wherein the configuration of the at least one adjustable high pressure opening and low pressure opening may be changed by selectively positioning the aperture of the at least one repositionable gate relative to the at least one corresponding stationary aperture in the housing. 
     
     
         11 . The device of  claim 9 , wherein the at least one repositionable gate is positioned to selectively form a seal between the high pressure port and low pressure port by selectively repositioning the aperture and the sealing surface of the at least one repositionable gate. 
     
     
         12 . The device of  claim 9 , wherein the housing includes a substantially cylindrical section and a corresponding cylindrical housing cap, wherein the cylindrical housing cap comprises a cap surface having a first helical groove and the cylindrical section comprises a cylindrical housing surface having at least one corresponding second helical groove, wherein when the cylindrical housing cap is mounted to the cylindrical section of the housing the cap surface and the cylindrical housing surface are in opposed facing relation to one another and an adjustable flow path for a fluid is formed between the first and at least one second helical grooves, the adjustable flow path in selective fluid communication with at least one of the high and low pressure openings of the device; and
 wherein selective circumferential and axial positioning of the cylindrical housing cap relative to the cylindrical section of the housing adjusts the flow rate of the fluid between the at least one port and through the adjustable flow path, so as to increase or decrease a heat exchange capacity of the adjustable flow path.   
     
     
         13 . The device of  claim 12 , wherein the at least one repositionable gate is circumferentially repositioned to selectively permit passage of the fluid through the adjustable flow path of the housing. 
     
     
         14 . The device of  claim 1 , wherein the at least one repositionable gate is selectively circumferentially positionable via an actuator. 
     
     
         15 . The device of  claim 14 , wherein the actuator drives a worm drive and wherein the at least one repositionable gate comprises a worm wheel of the worm drive. 
     
     
         16 . The device of  claim 10 , wherein the at least one repositionable gate is a high pressure gate, and wherein the aperture in the high pressure gate combined with the stationary aperture in the housing together comprise the adjustable high pressure opening between the first and second bodies and the high pressure port, the adjustable high pressure opening having a lower edge, and
 wherein the lower edge of the adjustable high pressure opening substantially lies in a plane that is substantially perpendicular to the first rotational axis.   
     
     
         17 . The device of  claim 16 , wherein the lower edge of the adjustable high pressure opening is positioned substantially along the first body outer surface and adjacent to the lobe tip of the first body at least once in a full rotation of the first complementary member. 
     
     
         18 . A rotary positive displacement device, comprising:
 a housing having a low pressure port and a high pressure port;   a first complementary member having a first body connected to a first shaft that is rotatable about a first rotational axis, the first body having a frusto-spherical outer surface, a frusto-spherical inner surface and an axial surface extending therebetween, wherein the axial surface comprises at least one teardrop surface and at least one engagement surface, the at least one teardrop surface further comprising a radially extending groove extending from the frusto-spherical inner surface to the frusto-spherical outer surface of the first body, the at least one teardrop surface and at least one engagement surface together defining at least one lobe and a corresponding valley, each lobe of the at least one lobe having a lobe tip,   a second complementary member having a second body connected to a second shaft that is rotatable about a second rotational axis, the second body having a frusto-spherical outer surface and an axial surface, wherein the axial surface comprises at least one teardrop surface and at least one engagement surface, the at least one teardrop surface and at least one engagement surface together defining at least one lobe and a corresponding valley, each lobe of the at least one lobe having a lobe tip, the second rotational axis intersecting with the first rotational axis;   the axial surface of each of the first and second bodies intermeshing with one another to form at least two chambers therebetween, the at least two chambers selectively separated by the axial surfaces of the first and second bodies, each chamber of the at least two chambers having a variable volume as the first and second bodies rotate about their respective rotational axes; and   a high pressure opening extending between the first and second bodies and the high pressure port of the housing;   a low pressure opening extending between the first and second bodies and the low pressure port of the housing, wherein the low pressure opening is configured to selectively communicate with one or more chambers of the at least two chambers;   wherein the lobe tip of the first body is in contact with, so as to form a seal against, the corresponding teardrop surface of the second body; and   wherein the lobe tip of the second body is selectively in contact with, so as to selectively form a seal against, the corresponding teardrop surface of the first body; and   wherein the engagement surface of each body of the first and second bodies is in contact with, so as to form a seal against, the corresponding engagement surface of the other body; and   wherein the high pressure opening comprises a lower edge, the lower edge positioned along an outer diameter of the frusto-spherical outer surface of the first body, wherein the lower edge is positioned between the first rotor shaft and the second rotor shaft.   
     
     
         19 . The device of  claim 18 , wherein each engagement surface is an involute surface. 
     
     
         20 . A rotary positive displacement device, comprising:
 a housing having a low pressure port and a high pressure port;   a first rotor comprising a first rotor body connected to a first rotor shaft that is rotatable about a first rotational axis passing through the first rotor shaft, the first rotor body having an outer surface and an axial surface;   a second rotor comprising a second rotor body connected to a second rotor shaft that is rotatable about a second rotational axis passing through the second rotor shaft, the second rotor body having an outer surface and an axial surface;   wherein the axial surface of each of the first and second rotor bodies comprises at least one offset advanced involute curve; and   wherein the axial surfaces of the first and second rotor bodies intermesh to form at least two chambers therebetween the first and second rotor bodies, the at least two chambers orbiting about the first rotational axis and each chamber of the at least two chambers has a variable volume as the first and second rotors rotate about their respective rotational axes; and   a low pressure opening extending between an outer diameter of the first rotor and the low pressure port of the housing, wherein the low pressure opening is configured to selectively communicate with one or more chambers of the at least two chambers;   a high pressure opening extending between an outer diameter of the first rotor and the high pressure port of the housing, wherein the high pressure opening is configured to selectively communicate with one or more chambers of the at least two chambers;   wherein the high and low pressure openings are each configured to selectively communicate with each other via at least one chamber of the at least two chambers.   
     
     
         21 . The device of  claim 20  further comprising at least one repositionable gate, the at least one repositionable gate having an aperture, the aperture of the at least one repositionable gate being selectively aligned with one of the high pressure port or the low pressure port of the housing to comprise at least one of an adjustable high pressure opening and an adjustable low pressure opening between the first and second rotors and the high pressure or low pressure port, and wherein the at least one of the adjustable high and low pressure openings are each configured to selectively communicate with each other via at least one chamber of the at least two chambers. 
     
     
         22 . The device of  claim 20  further comprising a high pressure gate and a low pressure gate, each of the high pressure gate and low pressure gate having at least one aperture, wherein each of the high pressure gate and the low pressure gate are independently circumferentially repositionable, the aperture of each gate being selectively aligned with each high and low pressure port to comprise at least one adjustable high pressure opening and at least one adjustable low pressure opening between the first and second rotors and each of the high pressure and low pressure ports, and wherein the adjustable high and low pressure openings are each configured to selectively communicate with each other via at least one chamber of the at least two chambers. 
     
     
         23 . A rotary positive displacement device, comprising:
 a housing having a low pressure port and a high pressure port;   a first rotor comprising a first body having a frusto-spherical outer surface and an axial surface, a first rotor shaft that is rotatable about a first rotational axis passing through the first rotor shaft;   a second rotor comprising a second body having a frusto-spherical outer surface and an axial surface, a second rotor shaft that is rotatable about a second rotational axis passing through the second rotor shaft;   wherein each axial surface of the first and second bodies comprises a multiple of two teardrop surfaces and a multiple of a corresponding two involute surfaces, wherein each teardrop surface and corresponding involute surface together defines a lobe and a corresponding valley, and wherein the axial surface of the first body intermeshes with the axial surface of the second body to form at least three chambers therebetween, each chamber of the at least three chambers separated from the other chambers by the axial surfaces of the first and second bodies and each chamber having a variable volume and a working fluid of a variable pressure contained within the variable volume as the first and second bodies rotate about their respective rotational axes; and   a high pressure opening extending between the first and second bodies and the high pressure port of the housing; and   a low pressure opening extending between the first and second bodies and the low pressure port of the housing, wherein the low pressure opening is configured to selectively communicate with one or more chambers of the at least three chambers; and   wherein the high pressure opening comprises a lower edge, the lower edge positioned along an outer diameter of the frusto-spherical outer surface of the first body, wherein the lower edge is positioned between the first rotor shaft and the second rotor shaft; and   wherein at any rotational position of the second rotor rotating about the second rotational axis, the variable pressure in each chamber of the at least three chambers acts to bias the second rotor in a first rotational direction with approximately the same force as the variable pressure in each chamber of the at least three chambers acts to bias the second rotor in a second rotational direction, opposite of the first rotational direction.   
     
     
         24 . The device of  claim 23  wherein each axial surface of the first and second bodies comprises two teardrop surfaces and two involute surfaces, the two teardrop surfaces and two involute surfaces together defining two lobes and two corresponding valleys, the device further comprising at least one repositionable gate, the at least one repositionable gate having an aperture, the aperture of the at least one repositionable gate being selectively aligned with one of the high pressure port or the low pressure port of the housing to comprise at least one of an adjustable high pressure opening and an adjustable low pressure opening between the first and second bodies and the high pressure or low pressure port, and wherein the at least one repositionable gate is selectively circumferentially positioned so as to align the gate aperture with each chamber of the at least three chambers such that each chamber will pass the gate aperture at a selected volume ratio and volumetric capacity of each chamber of the at least two chambers.