Patent Grant
9441629
According to various aspects, a rotary compressor is provided; more particularly a rotary compressor is provided having a gate that is configured to mount therein a housing and move in relation to an eccentric cam such that the gate's distal end is maintained at a substantially constant distance from an inner wall surface of the housing.
Various vane-type fluid displacement apparatuses have been proposed for use in certain limited applications. These proposed devices have primarily consisted of pumps, compressors, fluid driven motors, and fluid flow meters. The vane-type apparatuses heretofore proposed have generally performed satisfactorily and have gained acceptance for specific liquid applications. Common difficulties encountered with prior art vane-type apparatuses have included: an unsuitability for use with friction-reducing devices, which has traditionally limited their use to moderate power levels; a large fixed-surface to moving-surface contact area, resulting in high friction; an inability to withstand bending forces applied to the crankshaft; a reliance on discrete check valves or the like; and an inability to accommodate simultaneous reciprocating flow from each individual chamber.
Conventionally, a vane or gate compressor typically includes a cam ring, a rotor rotatably received within the cam ring, a drive shaft on which is secured the rotor, a front side block fixed to a front-side end face of the cam ring, a rear side block fixed to a rear-side end face of the same, a front head secured to a front-side end face of the front side block, a rear head secured to a rear-side end face of the rear side block, a plurality of axial vane slits formed in an outer peripheral surface of the rotor at circumferentially equal intervals, and a plurality of vanes radially slidably fitted in the axial vane slits, respectively. The drive shaft for rotating the rotor has opposite ends thereof rotatably supported by radial bearings arranged in the front and rear side blocks, respectively. Typically, a discharge chamber is defined by an inner wall surface of the front head, the front-side end face of the front side block, and the front-side end face of the cam ring, into which flows a liquid or gas delivered from compression chambers.
In another example of a prior art rotary compressor, the compressor mechanism can comprise a shaft adapted to be driven by a drive motor and having its upper and lower ends rotatably received by main and auxiliary bearings, respectively. An intermediate portion of the shaft extends through a cylinder that is fixed in position inside the sealed vessel. An eccentric portion is mounted on a portion of the shaft positioned within the cylinder for rotation together therewith. Further, a ring-shaped roller is operatively positioned between an inner wall surface of the cylinder and an outer peripheral surface of the crank and will, while the shaft is rotatably driven, undergo a planetary motion.
In one example, the cylinder will have a radial groove defined therein so as to extend in a direction radially thereof, and a slidable radial vane is accommodated within the radial groove for movement within the radial groove in a direction towards and away from the ring shaped roller. This slidable radial vane is normally biased by a biasing spring in one direction with a radially inward end thereof held in sliding contact with an outer peripheral surface of the ring-shaped roller such that, by dividing the volume of the cylinder into volumetrically variable, suction and compression chambers are defined on leading and trailing sides of the slidable radial vane, with respect to the direction of rotation of the shaft.
In this example, a liquid or gas is sucked into the suction chamber through the intake port and then compressed before it is discharged through a discharge port during the planetary motion of the ring-shaped roller as a result of the eccentric rotation of the crank. In order to facilitate a sliding motion of the ring-shaped roller relative to the inner wall surface of the cylinder and the radial inner end of the slidable radial vane and also a sliding motion of the radial vane within the radial groove, a quantity of lubricating oil is accommodated within the sealed vessel at a bottom portion thereof. In one example, the lubricating oil is sucked up by an oil pump mounted on the lower end of the shaft to oil various sliding elements within the compressor mechanism.
Of the various sliding elements used in such a conventional compressor mechanism, the slidable radial vane creates a detrimental problem when it becomes worn. As is well known to those skilled in the art, the slidable radial vane is frictionally engaged not only with the ring-shaped roller, but also with side surfaces defining the radial groove in the cylinder. Specifically, by the biasing force of the biasing spring and a back pressure acting on the trailing surface of the slidable radial vane, the radial inner end of the slidable radial vane is constantly held in frictional engagement with the ring-shaped roller and, also, opposite side surfaces of the slidable radial vane are alternately held in frictional engagement with the corresponding side surfaces defining the radial groove by the effect of a pressure difference between the suction and compression chambers. Unlike other sliding elements such as, for example, the shaft and its bearing mechanism, the slidable radial vane is not lubricated by the lubricating oil supplied directly by the oil pump, but is typically lubricated by an oil component, contained in the liquid or gas being compressed, and/or an oil leaking from roller ends. The quantity of the oil available from the fluid being compressed and leaking from the roller ends is normally insufficient for lubricating the slidable radial vane and its surrounding parts satisfactorily. In addition, considering that the fluid reaches an elevated temperature when compressed, the slidable radial vane in contact with the fluid being compressed becomes heated and is therefore susceptible to an accelerated frictional wear.
In such conventional vane pumps, as speed of the pump is increased, the centripetal force acting on the vane(s) presses them aggressively against the inner surface of the constraining housing, which beneficially provides a solid sealing force but also detrimentally creates high frictional forces between the vane's distal end and the inner surface of the housing. As one skilled in the art will appreciate, this increases frictional wear as well as reduces the compressor's operating efficiency.
U.S. Pat. No. 3,821,899 teaches a vane-type meter for use with petroleum or other fluid products. Its structure comprises: a housing having an inlet port and an outlet port; a rotating interior disc; an interior shaft held with respect to the rotating disk in a fixed, eccentric position with respect to the rotating disc; four radially extending, articulated vanes which rotate within the housing about the interior shaft; and four valving structures extending perpendicularly from the outer periphery of one side of the rotating disc. Each of the vanes includes an inner vane element consisting of: a substantially flat body; a single closed ring which extends from one end of the body and is rotatably positioned around the interior shaft; and an elongate, open C-shaped groove extending along the opposite end of the body. Each articulated vane also includes an outer vane element consisting of: a substantially flat body; an elongate pentil structure is formed along one end of the body and pivotally held in the C-shaped groove formed on the inner member; and a second elongate pentil structure formed along the other end of the body. The second pentil structure is pivotally held in one of the valving structures.
Fluid flow through the meter of U.S. Pat. No. 3,821,899 causes the disc, valving ports, and articulated vanes to rotate within the meter housing. As they rotate, the vanes form compartments, which change in volume and through which known amounts of liquid, are transferred from the inlet to the outlet of the device. Thus, the rotational speed of the device provides a direct indication of the fluid flow rate.
U.S. Pat. No. 2,139,856 discloses a pump or fluid-driven engine employing articulated vanes having shaped outer surfaces. The vanes form fluid chambers which continuously change in volume. In one embodiment, the apparatus of U.S. Pat. No. 2,139,856 comprises: a housing; a cylindrical casing held in fixed position within the housing; a crankpin mounted in the casing for eccentric revolving movement; eight articulated, two-part vanes, each having an inner end pivotally connected to the crankpin and an outer end pivotally connected to the casing; eight flow ports provided through a sidewall of the displacement chamber; a flow chamber provided between the casing and the housing; and eight flow ports and associated check valves provided in the casing between the outer ends of the vanes.
In a second embodiment of the device of U.S. Pat. No. 2,139,856, the crankpin is held at a fixed eccentric position within the casing and the casing rotates within the housing. As the casing rotates about the eccentrically positioned crankpin, the compartments formed by the articulated vanes successively draw fluid from inlet ports formed through one of the flat sidewalls of the displacement chamber, and then discharge the fluid through one or more fixed ports in the housing. Each of the articulated vanes has either one or two closed rings formed on the inner end thereof. These inner closed rings are rotatably positioned around the crankpin.
As previously noted, devices such as those proposed by U.S. Pat. No. 2,139,856 and U.S. Pat. No. 3,821,899 have several shortcomings. First, the devices fail to provide any adequate means for reducing frictional forces generated within the moving articulated vane assemblies. Additionally, the cost and complexity of the devices is significantly increased by the required use of completely separate fluid intake and discharge valve systems and/or port structures. Further, the devices provide no means for creating, accessing, and utilizing reciprocating flow regimes between adjacent pairs of articulate vanes. Also, the devices disclose no means for selectively configuring the vanes and displacement chambers in order to obtain specific desired flow patterns. Additionally, these designs have large and significant areas of metal-to-metal sliding contact with no means shown for reducing friction between the parts.
Thus, what is needed is a rotary compressor type device that experiences reduced frictional forces within its articulated rotary assemblies. Additionally, the device should be one that can be assembled, operated, and maintained cost effectively. Further, the device should be one that is more efficient and produces less noise and vibration during operation.
In various aspects, a rotary compressor is provided that more efficiently compresses a fluid, such as a liquid or gas, for a given energy input and does so with a lighter construction and improved output per cubic inch of overall size. In various aspects, the rotary compressor described with respect to various aspects herein does not rely on fixed cycle phases, eccentric shafts that induce friction, problematic compression chamber shapes, and does not tax the current state of the art in material sciences to accomplish its operational goals. It is contemplated that, in various embodiments, the device described herein can be used as a compressor for gaseous flow under pressure, or as a vacuum pump, or as a portion of a refrigeration assembly, or as a portion of a fluid power assembly, or as an expander for high pressure gases such as steam, or as a flow meter, or as a portion of an engine assembly that is constructed to operate as an internal combustion engine. In the latter example of an internal combustion engine, one skilled in the art will appreciate that how well such an engine brings in air, compresses it, captures the expansive forces, and then exhausts the burned gases, all determine the engine's relative performance and efficiency. In another aspect, the rotary compressor can be used as the compressor stage of a turbine engine as a means to achieve high pressure ratios within a small package. In other aspects, the rotary compressor can be used as the air feed compressor to a fuel cell package to supply high volumes of air at relatively low pressures. In some aspects, the rotary compressor can be configured as a supercharger for an internal combustion engine. In yet another aspect, the rotary compressor can be used as a waste heat recovery device when adapted into a bottoming cycle for known thermodynamic operations.
A rotary compressor described according to various aspects herein provides a purely rotational device that minimizes all of the conventional compressor stresses, and thusly, can be made from lighter materials with fewer structural requirements. In one aspect, the rotary compressor can be configured such that the intake fluid is ingested into an expanding space created by the relative motion between one solid element and another solid element. In this aspect, both elements form the ends of an expanding space as at least one of the elements moves in translation with respect to multiple inner surfaces disposed concentrically to said element's motion, said inner surfaces forming a passageway for the moving element to pass through and being sealed with sealing elements such that a substantial vacuum or substantial pressure can be created within the defined chamber as the moving element translates with respect to the volume-defining inner surfaces and with respect to the other element which can be fixed or moving in a chosen manner, typically also in a concentric nature to the first moving element. By providing ports that are fluidly connected to the working chamber provided during the intake stage of the device's operation, fluid (such as a liquid, gas such as air, or a two or three phase material) can enter into the working chamber as desired.
In another aspect, the intake tract of the rotary compressor can be configured to have low turbulence during intake chamber filling, which reduces turbulence losses and improves volumetric efficiency.
To create a functional rotary compressor, it is contemplated that in some aspects of the assembly, the opposing elements that are placed within the defined volume and are surrounded by the inner surfaces described above can move relative to each other and a port can be opened such that a liquid or gas can be allowed to enter the defined volume and at some point the port can be closed and the opposing elements moved toward each other in such a way as to reduce the volume contained within the defined space. The reduction in volume serves to increase the pressure within the defined space and, at a chosen point, a port (an additional port or the same port) can be allowed to open and the pressurized liquid or gas is allowed to escape the defined volume and put to other chosen uses.
In other aspects, the rotary compressor's rotational elements can be used to pump oil and/or coolant within the device without the need for auxiliary pumps, which simplifies the overall mechanical design. In another aspect, the rotary compressor may not need the use of an eccentric shaft and thusly can have lower frictional losses and provide a more direct conversion of the energy required to rotate the shaft into a compressed gas/liquid.
Additional advantages will be set forth in part in the description which follows, and in part will be obvious from the description, or can be learned by practice of the device described according to various aspects herein. The advantages of the device will be realized and attained by means of the elements and combinations particularly pointed out in the appended claims. It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the device, as claimed.
The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate several aspects of the invention and together with the description, serve to explain various principles of the invention.
The present invention may be understood more readily by reference to the following detailed description and drawings, and their previous and following description. Before the present devices, systems, and/or methods are disclosed and described, it is to be understood that this invention is not limited to specific devices, systems, and/or methods disclosed unless otherwise specified, as such can, of course, vary. It is also to be understood that the terminology used herein is for the purpose of describing particular aspects only and is not intended to be limiting.
As used herein, the singular forms “a,” “an,” and “the” include plural referents unless the context clearly dictates otherwise. Thus, for example, reference to a “gate” can include two or more such gates unless the context indicates otherwise.
Ranges may be expressed herein as from “about” one particular value to “about” another particular value. When such range is expressed, another embodiment includes from the one particular value and/or to the other particular value. Similarly, when values are expressed as approximations, by use of the antecedent “about,” it will be understood that the particular value forms another embodiment. It will be further understood that the endpoints of each of the ranges are significant both in relation to the other endpoint, and independently of the other endpoint.
As used herein, the terms “optional” or “optionally” mean that the subsequently described event or circumstance can or cannot occur, and that the description includes instances where said event or circumstance occurs and instances where it does not.
Reference will now be made in detail to the present preferred aspects of the invention, examples of which are illustrated in the accompanying drawings.
It is contemplated that the device described according to various aspects herein can function as a compressor, a pump, a flow meter, an expander, and/or an engine. Generally, for clarity, the device is described herein as a rotary compressor, but it is of course contemplated, as one skilled in the art will appreciate, that the device can function in a variety of applications such as described above. The working fluid in any particular application can be a liquid, a gas, or can comprise a two-phase flow regime as desired for the selected application of the device.
According to one aspect, a rotary compressor is provided that comprises a housing, a rotor, and a gate. An exemplary rotary compressor is illustrated in
According to yet another aspect, at least portions of the peripheral surface of the rotor, portions of the inner wall surface of the housing, and varying portions of the gate proximate the distal end of the gate can define a compression chamber 102 of varying volume as the rotor rotates about the rotor axis of rotation. At least portions of the peripheral surface of the rotor, portions of the inner wall surface of the housing, and varying portions of the gate proximate the distal end of the gate can also define a suction chamber 104, such as illustrated in
An exemplary rotary compressor is illustrated in
An exemplary housing front cover 113 is illustrated in
An exemplary housing back cover is illustrated in
An exemplary rotor 150 is illustrated in
According to one aspect, the rotary compressor further comprises means for providing a substantially fluid-impervious seal between the first end plate 151a and the front surface of the housing 111, and between the second end plate 151b and the back surface of the housing 112. In one exemplary aspect, at least one slot can be defined in peripheral portions of each of the first and second end plates. A plurality of seals can be provided, each seal being configured for complementary mounting therein one slot of the first and second end plates.
Optionally, at least one slot 122 can be defined in each of the front surface 111 and back surface 112 of the housing, the at least one slot substantially surrounding the interior cavity of the housing. At least one seal can be provided, each seal being configured for complementary mounting therein one slot of the housing. For example, as shown in
In yet another aspect, a first end plate of the pair of end plates can be mounted to the front surface of the housing, and a second end plate of the plurality of end plates can be mounted to the back surface of the housing. The rotary compressor can further comprise means for providing a substantially fluid-impervious seal between the first end plate and a first side surface of the rotor, and between the second end plate and a second side surface of the rotor. In one aspect, at least one slot is defined in peripheral portions of each of the respective first and second side surfaces of the rotor. At least one seal can be provided, each seal being configured for complementary mounting therein one slot of the rotor.
The rotary compressor, in one aspect, comprises a cam 128, such as shown in
An exemplary eccentric shaft 129 is illustrated in
An exemplary cam 128, such as shown in
As described above, the rotary compressor in various aspects comprises a pair of end plates 151a, 151b that can be mounted to and rotate therewith the respective first and second side surfaces of the rotor. As shown in
In a further aspect, the protrusion of the first end plate can have a blind bore that extends a predetermined depth from an inner surface of the first end plate into the protrusion, such as shown in the cross-sectional view of
In one aspect, the eccentric shaft can be supported by a nested anti-friction bearing positioned therein the bore of the protrusion; the bearing can be constructed of known bearing elements, such as but not limited to, bushings, roller bearings, journal bearing, taper roller bearings, or the like. In some aspects, the nested bearing can be a taper roller bearing, and adjustment means can be provided within the distal end portion of the eccentric shaft to allow for some axial movement of the eccentric shaft and rotor to accommodate for wear or assembly tolerances, such that the rotor can be aligned properly with respect to the housing. In other aspects, thrust bearings can be provided to achieve the desired alignment for the rotational elements.
Similarly, it is contemplated that the second end plate 151b can define a bore that extends therethrough the second end plate, which can be configured for receiving a distal end of the eccentric shaft. As described with respect to the rotor front bearing, the distal portion of the eccentric shaft can be inserted therethrough a rotor back bearing 153 and then inserted through the bore in the second end plate to allow the rotor to rotate relative to and about the eccentric shaft.
In one aspect, the first end plate, second end plate, or both the first and second end plates can have a slight protrusion along a portion of its circumference that provides a cam-like profile (shown, for example, in
According to various aspects, the rotor 150 defines a bore 155 configured for slidable receipt of the gate, such as shown in
In a further aspect, the gate can be generally cylindrical and the bore of the rotor can be complementarily cylindrical in shape to receive the gate. Optionally, the gate can have a non-cylindrical shape and the bore of the rotor can be complementarily shaped to receive the gate. A gate 160, such as exemplarily shown in
In one aspect, the gate can comprise an upper eccentric plate 163a and a lower eccentric plate 163b, such as shown in
In one aspect, the rotary compressor comprises means for minimizing distortion and deflection of the gate at high fluid pressures. In one aspect, at least a portion of the bore of the rotor can have a cylindrical cross-sectional shape and at least portions of the gate can have a cylindrical cross-sectional shape that is complementary to the bore of the rotor. In this aspect, the cylindrical shape of portions of the gate can provide improved resistance to gate distortion and deflection at high fluid pressures and high rotational speeds due to a superior moment of inertia.
In a further aspect, the gate can have additional support for proper alignment during its axial movement via an internal guide pin affixed to the rotor and extending along the axis of the gate bore provided within the rotor. In this aspect, the guide pin can be received within a bore provided within the gate itself running along its longitudinal axis. In this way, the side forces pressing upon the gate can be carried by both the gate bore within the rotor and by the guide pin residing within the bore. Optionally, there can be bearing elements provided within the gate's internal bore upon which the guide pin can ride to reduce frictional loads.
In yet another aspect, the rotary compressor comprises at least one sealing element mounted thereon exterior portions of the portions of the gate having the cylindrical cross-sectional shape. For example, as illustrated in
As described above, in one aspect, the gate is slidably mounted therewith the rotor and is movable axially about and between the first position, in which the distal end of the gate is positioned at a first distance from the peripheral surface of the rotor, and the second position, in which the distal end of the gate is positioned at a second distance from the peripheral surface of the rotor. In one aspect, the first distance is greater than the second distance. The second distance can be proximal to the peripheral surface of the rotor, in one aspect. In yet another aspect, in the second position, the distal end of the gate can be at or below the peripheral surface of the rotor.
The distal end of the gate can be constrained to be spaced proximate from the inner wall surface of the housing as the rotor rotates about the rotor axis of rotation. In one aspect, the distal end of the gate can be constrained to be proximate from the inner wall surface of the housing in a constrained range of between about 0.0001 inches to about 0.2000 inches. Optionally, the distal end of the gate can be constrained to be spaced proximate from the inner wall surface of the housing in a constrained range of between about 0.0003 inches to about 0.1500 inches. In yet another aspect, the distal end of the gate can be constrained to be spaced proximate from the inner wall surface of the housing in a constrained range of between about 0.0005 inches to about 0.1000 inches.
According to various aspects, the distal end of the gate defines a slot. The rotary compressor can further comprise a seal assembly comprising at least one planar member movable therein the slot of the gate, and a bias element configured to selectively act on the at least one planar member to maintain the outer edge of the at least one planar member in sliding contact with the inner wall surface of the housing as the rotor rotates. In one aspect, the mass of the at least one planar member is less than about 50 percent of the mass of the gate. In another aspect, the mass of the at least one planar member is less than about 10 percent of the mass of the gate. Optionally, the mass of the at least one planar member can be less than about 2 percent of the mass of the gate. According to yet another aspect, the mass of the at least one planar member can be between about 1 to about 60 percent of the mass of the gate. It is also contemplated that, optionally, the biasing force for the at least one planar member can be provided at least in part by the pressurized gases of the compression chamber through the provision of passageways fluidically connecting the compression chamber to the underside of the sealing element.
In one aspect, the distal end of the gate can be generally tapered, such as shown in
The noted configuration of the tapered end portion of the gate reduces the gradient for total volume reduction as the rotor spins, that is, as the gate retracts downwardly into the bore of the rotor, it is adding a small amount of incremental volume for each degree of rotor rotation, which reduces the rate at which the total volume decreases. Thus, the exemplified configuration moves some of the volume down into the bore as the crescent shape closes up. Because the “bore volume” increases slower than the reduction in the crescent volume, the result is a net compression event.
It is contemplated that alternative shapes for the distal end portion of the gate can be used. In various aspects, different geometric shapes can be used on one or both sides of the tapered end portion of the gate to optimize either a compression or an expansion operation. For example, in one aspect, if the end portion of the gate does not have a taper on the compression side, an increase in the compression ratio would result. Alternatively, by providing a steep taper (i.e., a larger height to width ratio of the tapered portion of the distal end portion of the gate) on the suction side, the volume ingested for each “stroke” is increased. If the present device is used as an expander, it is contemplated that the tapered end portion of the gate can be configured to create the highest resultant moment reaction for a given portion of the rotation, such as, for example and not meant to be limiting, creating a substantially “constant volume expansion” stroke by varying the geometry of the gate's profile on its distal end.
The exemplary tapered end portion of the gate, as described above, can provide a retracting ‘pocket’ in the gate on which the pressure can act or through which the suction volume can be increased. The tapered configuration allows some volume to grow in the compression chamber as the rotary compressor moves toward the final clearance volume. The particular shape of the tapered end portion provides a means for tuning the compression dynamics rather than just rely on the gate/housing geometry alone.
According to various aspects, at least one slot is defined by the distal end of the gate. In one aspect, the slot 164 defined by the distal end of the gate is a three-sided slot, such as shown in
The slot 164, in one aspect, can be configured to complementarily and operatively receive an apex seal 166 and a pair of side seals 167, such as shown in
A pair of gate seal actuators 168 (illustrated in
In one exemplary aspect, each of the side and apex seals is generally trapezoidal in shape. Due to the general geometry of the gate seal actuators, the side seals, and the apex seal, sealing of the gate against portions of the housing and/or the rotor can be effectuated. The gate actuator spring acts on the gate seal actuators, which can slide longitudinally within the bore in directional parallel to the longitudinal axis of the gate actuator spring. The gate seal actuators, in turn, act against the side seals 167, which in turn act against the apex seal 166. The angled-end geometries of the seals allow for applied forces from the spring to press the side seals outward against their respective mating surfaces (in one aspect, against the inner surfaces of the pair of end plates) while also translating this force up to the apex seal, thereby forcing it against the inner wall surface of the housing. Thus, the lateral force of the spring is transferred to the side seals, creating a seal between the gate and the first and second end plates. Due to the angled interface between the side seals and the apex seal, the lateral force of the spring is translated through the side seal as a lateral and upward force, pressing the apex seal against the inner wall surface of the housing. Optionally, the compression fluid within the compression chamber can be directed through passageways provided in the seals themselves or within the gate such that the pressurized fluid acts upon the underside of chosen seals to provide all or part of the biasing force necessary for fluidic sealing of given chambers.
According to yet another aspect, the rotary compressor further comprises a seal element extending outwardly from the inner wall surface of the housing proximate the location of minimal running clearance between the inner wall surface of the housing and the peripheral surface of the rotor. An edge of the seal element can be configured for selective slidable contact with the peripheral surface of the rotor. In a further aspect, the rotary compressor can comprise means for withdrawing the seal element within the housing such that the edge of the seal element is at or below the inner wall surface of the housing when the distal end of the gate passes over the seal element as the rotor rotates.
In one aspect, at least one top dead center (TDC) assembly is provided and comprises the seal element. The TDC assembly 130 can be inserted therein and forms a portion of the housing 110, such as shown in
The TDC insert 131 comprises the main body portion of the TDC assembly and has an inner surface that is substantially continuous with the inner wall surface of the housing when the TDC assembly is inserted therein a cut-out of the housing. The inner surface thus has a radius of curvature substantially equal to the radius of curvature of the inner wall surface of the housing. A groove or TDC seal land is defined in a portion of the inner surface and is configured to complementarily receive the seal element, such as the TDC surface seal and the TDC side seals. When the TDC assembly is positioned therein the housing, the groove extends substantially from the front surface of the housing to the back surface of the housing. In a particular aspect, the groove is positioned at an acute angle relative to the front surface of the housing. In a preferred aspect, the groove is positioned at an angle that is not perpendicular to the front surface of the housing, such as illustrated in
In yet another aspect, at least one cavity 140 is defined in the respective front and back surface of the TDC insert 131. In this aspect, each cavity extends partially inwardly into the TDC insert (i.e., blind bores). Each cavity is configured for operative receipt of a TDC button seal 137. Optionally, additional cavities can be defined in the TDC insert, which extend into the TDC insert from the outer surface of the TDC insert. In an exemplary aspect, the cavities can extend from the outer surface of the TDC insert to the TDC seal land. In another aspect, two of the cavities can be configured to operatively receive the seated spring members 138, such as shown in
A bore can be defined therein the TDC insert and can be configured to operatively receive the pull rod 136. Optionally, a plurality of bores can be defined therein the TDC insert, each bore configured for receiving a respective pull rod. In one aspect, a distal end of the pull rod, shown for example in
The cross bar can be operatively engaged by the first and second end plates 151a, 151b in one aspect, to position the seal element of the TDC assembly such that it is at or below the inner wall surface of the housing when the distal end of the gate passes over the seal element as the rotor rotates. For example, as described above, one or more of the first and second end plates can have a protrusion along their periphery, resulting in a cam-like profile. As the protrusion passes over and contacts one or both ends of the cross bar that extend beyond the front and back surfaces of the housing, the cross bar is moved and thereby draws the seal element to a position at or below the inner wall surface of the housing. It can be appreciated that alternative actuation means can be used to articulate the TDC seal element without departing from the scope of the present disclosure and all such articulating means are contemplated by the present disclosure. It is contemplated that such actuation means can include, but are not limited to, pneumatic, hydraulic (such as using an external fluid, control fluid, and/or the working fluid of the rotary compressor, etc.), electronic, electro-mechanical, or other known means of providing mechanical movement.
Referring to
According to one aspect, the housing can have at least one housing inlet port 124 that is in fluid communication with the suction and/or compression chamber, such as illustrated in
Similarly, in one aspect, the rotor, gate, first and/or second end plates, housing, and/or other component(s) of the rotary compressor can have at least one outlet port in fluid communication with the compression chamber. For example, in a particular aspect, the gate can have at least one outlet port 195 in fluid communication with the compression chamber, such as shown in
In a further aspect, the axial movement of the gate within the rotor can be used to open ports provided in the gate as they become aligned with ports provided in the rotor. In this aspect, during select periods of rotor movement the outlet port is placed in fluid communication with one or more volumetric chambers to allow fluid flow therebetween. In yet other aspects, outlet ports can be provided in the rotor endplates, which are allowed to be placed in fluid communication with selected volumetric chambers as the rotor endplates moves eccentrically with respect to the housing. In this exemplified aspect, during select periods of rotor movement, the ports allow fluid communication to be established, which allows for the ingestion or discharge of fluid from one or more of the volumetric chambers. Alternatively, it is contemplated that ports can be provided in at least a portion of the housing that are configured to provide the primary inlet or outlet passageways for the working fluid, or the formed housing ports can serve as additional ports to main ports provided in other components as described above.
The rotary compressor can further comprise a discharge valve mounted thereto the housing that serves to prevent back flow of the compressed fluid in the compression chamber. In other aspects, the rotary compressor can comprise an intake valve positioned therein the intake passageway (such as, but not limited to, positioned therein an inlet port of the housing) to reduce or eliminate reversion flow of the intake fluid. According to various aspects, for example and not meant to be limiting, the discharge valve and/or intake valve can comprise a reed valve, a plate valve, a flapper valve, and the like.
Referring now to
According to various aspects, the rotary compressor can comprise a rotor having a peripheral surface and a rotor axis, and a housing defining an internal cavity having an inner wall surface, and the housing can be configured to rotate about a housing longitudinal axis eccentric to the rotor axis. The rotor can be positioned within the internal cavity of the housing. A gate, such as described herein, can be slidably mounted therewith the rotor and movable axially about and between a first position, in which the distal end of the gate is positioned at a first distance from the peripheral surface of the rotor, and a second position, in which the distal end of the gate is positioned at a second distance from the peripheral surface of the rotor. In this aspect, first and second end plates can be provided and can be fixedly attached or mounted thereto the rotor. Thus, the rotor and the end plates can be held or maintained in a stationary position as the housing rotates about the housing longitudinally axis. Such a rotary compressor can be used for example, as a compressor, pump, expander, or any combination thereof.
It is contemplated that compound devices can be assembled using two or more rotary compressors as described herein to create high pressure ratios as can be desired. In an exemplary aspect, the first stage rotary compressor can have its outlet port or ports positioned selectively in fluid connection with the inlet of a secondary stage rotary compressor. In various aspects, the secondary stage can be, without limitation, any one of a number of known compressor devices such as a centrifugal compressor, a scroll compressor, a reciprocating compressor, an axial turbine compressor, or the like. Alternatively, it is contemplated that the first stage can be comprised of a known compressor or pump, as exemplarily described above, and subsequent stages can be assembled using a rotary compressor as described according to various aspects herein, or combinations thereof. Such a multi-stage compressor can be used, for example and without limitation, as a compressor, pump, expander, engine, or any combination thereof.
With reference to
According to various aspects, it is contemplated that the seal actuator presses against the gate side seals, pressing the gate side seals against the inner surfaces of the first and second end plates. As described above, due to the construction and geometrical shape of the gate side seals and gate apex seal, the lateral force experienced by the gate side seals is translated to the gate apex seal in a transverse direction, thereby pressing the gate apex seal against the inner wall surface of the housing. These pressing forces can serve to ensure proper sealing during operation of the rotary compressor. In one aspect, the gate side seals experience pressing forces in the range of between about 0.01 pounds and about 15.0 pounds. In a further aspect, the gate side seals experience preferably about 4.0 pounds of force. According to another aspect, the gate apex seal experiences a pressing force in the range of between about 2.0 to about 40.0 pounds. In yet another aspect, the gate apex seal and gate side seals can be constructed with alternative spring elements to cause the forces described herein above.
In one aspect, a TDC assembly is provided and can be mounted therein the housing. The TDC insert can be positioned within the housing and the distal end of the TDC pull rod can be inserted into the notch of the TDC surface seal, which can in turn be inserted into the groove or TDC seal land in the TDC insert. The TDC side seals can likewise be inserted into the groove, and the button seals can be inserted into respective bores on the front and back surfaces of the TDC insert. The TDC cross bar can be inserted into a bore (as shown, for example, in
The rotor (with gate positioned therein) can then be positioned within the internal cavity of the housing. In one aspect, the general rotor position within the housing (i.e., the position of the rotor defined by the position of the rotor axis of rotation relative to the housing longitudinal axis), and relative to the housing, is constant, despite the rotational movement of the rotor within the housing. Thus, there is a point or location at which the peripheral surface of the rotor and the inner wall surface of the housing are closest, such as illustrated in
The eccentric shaft and cam can be inserted therein the centrally positioned chamber of the rotor and the defined hollow portion of the gate. The cam can be positioned along the eccentric shaft such that it is positioned therein the hollow of the gate, proximate the at least one bearing surface defined by the hollow. In one aspect, the cam can be positioned therebetween the upper and lower eccentric plates of the gate. It is contemplated, according to various aspects, that the shape of the cam can be chosen such that the gate, which is constrained within the rotor by the rotor bore, has its radial position defined by the contact points between the cam and the mating contact points on the at least one bearing surface of the gate hollow, such as the upper and lower eccentric plates. As the rotor rotates about the rotor axis of rotation, the circumferential path of the gate is defined by the center of rotation of the rotor, and the gate's radial distension is fixed by the geometry of the cam. In this way, the distal end of the gate is constrained to be spaced proximate from the inner wall surface of the housing, and is constrained from pressing with excessive or erratic force against the inner wall surface of the housing.
In one aspect, the cam is designed such that the distal end of the gate can be maintained at a spaced distance proximate from the inner wall surface of the housing. In one aspect, the distal end of the gate is constrained to be spaced proximate from the inner wall surface of the housing in a constrained range of between about 0.0001 inches to about 0.2000 inches, in a constrained range of between about 0.0003 inches to about 0.1500 inches, or in a constrained range of between about 0.0005 inches to about 0.1000 inches. In another aspect, the distal end of the gate is constrained to be spaced proximate from the inner wall surface of the housing in a constrained range of between 0.01% and 15.0% of the diameter of the housing inner surface.
In this manner, wear and contact friction between the gate and the inner wall surface of the housing can be minimized or eliminated. As described herein, sealing between the distal end of the gate and the inner wall surface of the housing (and/or the inner surfaces of the first and second end plates) can be accomplished by the spring force of the gate seal actuator acting on the gate side seals and the gate apex seal. In other aspects, sealing between the distal end of the gate and the inner wall surface of the housing (and/or the inner surfaces of the first and second end plates) can be accomplished by close running clearances achieved through exact machining and assembly tolerances, thereby creating a non-contact sealing function and thus reducing friction and wear.
A proximal portion of the eccentric shaft can be inserted through the rotor front bearing into the bore formed in the shaft of the first end plate. Similarly, a distal portion of the eccentric shaft can be inserted through the rotor back bearing, through the second end plate, and inserted into the mating bore in the housing back cover. In one aspect, the housing front spacer is positioned between the housing front cover and the front surface of the housing. As shown in
It is contemplated that the rotary compressor can be joined together or assembled with conventional means, such as, for example and without limitation, mechanical fasteners such as, without limitation, screws, bolts, rivets, clamps, pressed studs with nuts, and the like, or any combination thereof. Complementary fastener holes can be defined, such as illustrated for example in
According to various aspects, the first and second end plates can be fixedly attached to the first and second side surfaces of the rotor, respectively, such that they rotate simultaneously with the rotor. In one aspect, the first and second end plates can be substantially sealed against the front and back surfaces of the housing by at least one seal positioned therein a respective slot defined in the front and/or back surface of the housing. In this aspect, the gate side seals translate axially up and down relative to the inner surfaces of the first and second end plates, rather than sweeping against them if they were fixed relative to the rotation of the rotor. In this manner, sealing performance can be improved and friction can be reduced. As can be appreciated, any number of seals can be used to provide sealing of the gate within the rotor and of the gate against the inner wall surface of the housing, and it is contemplated that various aspects can include more or fewer seals than described herein. It is contemplated that, in some aspects, one or more of the seals can be urged against their mating surfaces through, for example and not meant to be limiting, the use of fluid pressure routed from the compression chamber or elsewhere, or through the use of bias elements, or a combination thereof.
According to other aspects, the first and second end plates can be fixedly attached to the housing. For example, the first end plate can be mounted to the front surface of the housing and the second end plate can be mounted to the back surface of the housing. Means can be provided for providing a substantially fluid-impervious seal between the first end plate and the first side surface of the rotor and between the second end plate and the second side surface of the rotor. In this aspect, it is contemplated that the gate side seals will ‘sweep’ against the inner surfaces of the first and second end plates, rather than moving axially or laterally against them as described herein in accordance with various other aspects. According to various aspects, it is contemplated that fewer seals (e.g., gate seals, TDC seals, etc.) can be provided and sealing can be effectively achieved through close assembly tolerances at selected interfaces between components of the rotary compressor. Optionally, an oil-less compressor or vacuum pump can be constructed through the elimination of chosen sealing elements such that the desired performance can be achieved through the exact positioning of the gate relative to the housing, i.e., by positioning the gate such that the distal end of the gate remains at a close select tolerance from the housing. This aspect can achieve long service life through the reduction of friction and wear at the typical seal contact points.
In operation, as the rotor rotates within the housing, the gate assembly is axially moved about and between the first and second position, as described above. When the distal end of the gate approaches the point at which the rotor and housing are closest (i.e., at substantially the TDC position), the cam-like profile of the first and second end plates cause the TDC cross bar to move outwardly, away from the inner wall surface of the housing, which causes the pull rod to exert a pulling force on the TDC surface seal. The TDC surface seal is thereby retracted to a position at or below the inner wall surface of the housing.
According to a further aspect, the retraction of the TDC surface seal described above can substantially coincide with the movement of the gate past the TDC position, and allows the gate to pass the TDC position while minimizing or eliminating any contact between the gate apex seal and the TDC surface seal. Thus, the cam-like protrusions in each of the first and second end plates can be located and profiled to provide a predetermined amount of lift to the TDC surface seal to prevent it from being struck or contacted by any portion of the gate as the gate passes the TDC position.
According to various aspects, additional means can be provided to prevent the TDC surface seal from adversely contacting the gate apex seal. For example, the TDC surface seal can be positioned at an angle (described above) with respect to the front and back surfaces of the housing, such that the gate apex seal and the TDC surface seal are not parallel as the gate passes the TDC position (thereby preventing full contact between the two seals). The angled positioning of the TDC surface seal can further prevent the gate apex seal from catching or dropping into the groove or seal land formed in the TDC insert configured for receiving the TDC surface seal. In another aspect, the TDC surface seal retraction can be caused by the gate apex seal through a pushing force provided by the gate apex seal as it travels past and contacts the TDC surface seal, forcing the TDC surface seal to retract into the groove of the TDC insert.
According to yet another aspect, it is contemplated that the TDC surface seal can be a fixed seal (i.e., it would remain stationary and not be retracted into the groove or seal land of the TDC insert). In this aspect, the gate apex seal can be configured with means for translating the gate apex seal inwardly toward the housing longitudinal axis as the gate apex seal passes the “fixed” TDC surface seal. The means for translating can comprise a cam surface on the eccentric cam that is configured to control the position of the gate apex seal relative to the distal end of the gate as the rotor rotates within the housing.
Due to the geometries and relative positioning of the TDC surface seal, side seals, and TDC button seals (such as shown in
In operation, in one aspect, the TDC side seals can engage the respective first and second end plates along a small contact area, causing wear at that interface. In one aspect, as the TDC side seals wear, they engage the TDC button seals, which seal the compression chamber above the TDC surface seal. Further, in operation, the TDC side seals exert pressure onto respective TDC button seals against the inner surfaces of the respective first and second end plates, which restricts the TDC side seals' contact and pressure against the first and second end plates. In this aspect, the large combined surface area of the TDC button and side seal interface against the respective end plates reduces the applied pressure, which can effectively reduce wear to a minimal amount. In another aspect, this exemplified embodiment of the TDC button and side seals ensures that the side seals will substantially always be pressing against the internal surface of the button seal for maximizing the desired sealing.
In operation, fluid intake (such as air or other gas intake, liquid intake, etc.) is achieved via the various inlet ports described above. For example, inlet port(s) can be formed in the housing back cover that are in sealed fluid communication with an inlet port formed on the second end plate. The inlet port of the second end plate can be in fluid communication with an inlet port of the rotor. Thus, fluid, such as air, can be brought into the suction chamber of the rotary compressor. As can be appreciated, in an initial rotation of the rotor, fluid will be drawn into the suction chamber of the rotary compressor, defined behind the gate. At the end of the initial rotation, when the gate passes the TDC position, the fluid that was drawn into the suction chamber of the initial rotation becomes fluid in the compression chamber of the subsequent rotation.
Through this air (or other fluid) passageway, for example, air can be naturally pumped or drawn into the suction chamber by the rotation of the rotor and the low pressure (e.g., vacuum) force created by the movement of the rotor assembly (i.e., as the suction chamber volume behind the gate expands). Additionally, by having the air enter into the suction chamber through a side surface of the rotor, less flow inertia is necessary to fill the working chamber than in known compressors. Rather, air is “laid out” into the suction chamber by the inlet port in the rotor's side surface as the rotor rotates about the rotor axis of rotation. Each discrete element of the air enters into the suction chamber without having to push additional air out of its way, as is the case with known poppet and flapper valves. Instead, each discrete element of air is “pulled” into the suction chamber by the pressure gradient created by the rotor's movement.
In an expansion mode of operation, fluid flow can be sent through the rotor and out its periphery into the expansion chamber through a port provided proximate to and behind the gate. In this aspect, the fluid that is pressing against the gate does not have to transfer its pressure force through all the previously injected fluid, but rather the fresh charge of fluid pressure is always fed proximate to and behind the gate's distal end.
In another aspect, the air (or other fluid) intake allows the rotor to be cooled by the incoming air charge, which can aid in the longevity and efficiency of a rotary compressor assembled according to various aspects described herein.
In one aspect, the compression ratio of the rotary compressor can be determined by the selective positioning of the inlet and outlet ports described herein. The full rotation of the rotor within the rotary compressor can provide nearly a full 360 degree intake and compression “stroke.” This can be altered in a fixed manner through the selective location of the inlet and/or outlet ports. Optionally, the stroke of the rotary compressor can also be made changeable, or variable in real time by using a moving port location. In this aspect, conventional shutters, sliding ports, sleeves, or similar means to change the location of the ports (inlet ports, outlet ports, or both) with respect to the rotor's position in its rotation can be used to vary the stroke of the rotary compressor. Likewise, it is contemplated that the amount of fluid ingested into the suction chamber can be variable using similar means.
According to yet another aspect, the bottom portion of the gate (i.e., the proximal portion opposite the distal end of the gate) can be used as a control valve, pump, etc. as can be envisioned from observing that the proximal portion of the gate is moved axially within the rotor bore. In this aspect, the rotor bore can be a blind bore. Thus, in the closed bottom portion of the bore, a closed working volume can be created wherein the up and down axial motion of the gate will expand and contract the volume of this closed working volume. This expansion and contraction can be used, through the incorporation of chosen valves, ports, and similar components of pumps or compressors, to effect a pump or compressor function in the bottom portion of the bore. Likewise, the proximal portion of the gate can be used as a sliding valve or sleeve valve through the use of ports formed therein the rotor bore at selected locations.
According to various aspects, the bottom or proximal portion of the gate can be configured to act as an additional gate, and can comprise a gate seal assembly (i.e., a gate apex seal and gate side seals positioned therein a respective slot at the proximal end of the gate) configured to contact the inner wall surface of the housing. As can be appreciated, by doubling the number of gates, the number of chambers therein the rotary compressor can be doubled. It is contemplated that additional inlet and outlet ports can be provided within the rotor and/or housing to effect the fluid flow into and out of the rotary compressor to maximize pumping efficiency. According to yet another aspect, a plurality of gates can be provided to increase the suction, compression, and/or pumping functions of the rotary compressor.
Referring now to
According to various aspects, means for cooling the rotary compressor can be provided, such as but not limited to cooling fins placed in selected locations on the exterior of the housing, first and second end plates, and/or other locations, such that ambient air can access the cooling fins and promote heat transfer away from the apparatus into the ambient air. In other aspects, specific cooling circuits can be provided that incorporate air-to-air, liquid-to-air, air-to-liquid, or liquid-to-liquid cooling processes to achieve the desired cooling.
According to yet another aspect, the intake air can be routed through passages provided in the high temperature components of the rotary compressor to augment heat flux out of these areas and into the intake air stream. In some aspects, an external fan can be provided to facilitate air flow over the rotary compressor. Optionally, an oil cooling circuit can be utilized to provide the desired level of cooling. In some aspects, an oil separator device can be incorporated into the oil cooling circuit in which the outlet air is conditioned such that any airborne oil within the discharge stream is removed, cooled, and recirculated into the device.
As described above, in one aspect, the opposed bearing surfaces of the gate can interact with an eccentric cam to effect the axial movement of the gate within the rotor. According to another aspect, such as illustrated in
Referring to
As exemplarily illustrated, in the various embodiments described herein, it is contemplated that the shape of the internal cavity of the housing can be selected to complement the shape of the cam, and vice versa, such that the distal end of the gate can be constrained to be spaced proximate from the inner wall surface of the housing as the rotor rotates about the rotor axis of rotation.
According to various other aspects, the rotary compressor can comprise gate assemblies comprising one or more gates and/or comprising one or more end portions configured to be spaced proximate from the inner wall surface of the housing. For example, as illustrated in
In one aspect, at least portions of the peripheral surface of the rotor 450, portions of the inner wall surface of the housing 410, and varying portions of the dual-end gate 460 proximate the distal end of the dual-end gate define a first compression chamber of varying volume as the rotor rotates about the rotor axis of rotation. Similarly, at least portions of the peripheral surface of the rotor, portions of the inner wall surface of the housing, and varying portions of the dual-end gate proximate the proximal end of the dual-end gate define a second compression chamber of varying volume as the rotor rotates about the rotor axis of rotation.
According to yet another aspect, at least one inlet port 475 can be formed therein the dual-end gate assembly. In a particular aspect, an inlet port is formed therein each of the distal and proximal ends of the dual-end gate. In one aspect, the distal end can define at least one inlet port in fluid communication with the first compression chamber. In another aspect, the proximal end can define at least one inlet port in fluid communication with the second compression chamber. According to yet another aspect, each of the distal end and proximal end can define at least one inlet port in fluid communication with the first compression chamber and second compression chamber, respectively.
According to various aspects, the rotary compressor can further comprise means for selectively opening and closing the at least one inlet port therein the respective distal end and proximal ends of the dual-end gate. For example and not meant to be limiting, as illustrated in the cross-sectional view of
As shown in
In one aspect, a TDC assembly can be provided therein the housing, such as described above. Of course, it is contemplated that the housing, such as shown in
As described above, a gate having dual end portions can be formed as a unitary dual-end gate assembly. Optionally, and with reference to
According to yet another aspect, the rotary compressor can comprise a quad-gate assembly 660, such as illustrated in
A prototype rotary compressor was constructed as illustrated in
where {dot over (m)}act is the measured mass flow rate (kg/s); ν1 is the specific volume at state point 1 (m3/kg); {dot over (V)}th is the theoretical volume flow rate (m3/s); h1 is the enthalpy at state point 1 (kJ/kg); h2s is the enthalpy at state point 2 for an isentropic compression process (kJ/kg); and {dot over (W)}comp is the input power to the compressor (W).
Additional tests were performed to measure the “dead head” pressure capabilities of the prototype. At 1200 rpm, a pressure ratio exceeding 38:1 was recorded. The results of this test can be seen in
It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the scope or spirit of the invention. Other aspects of the invention will be apparent to those skilled in the art from consideration of the specification and practice of the invention disclosed herein. It is intended that the specification and examples be considered as exemplary only, with a true scope and spirit of the invention being indicated by the following claims.
This application is a continuation of U.S. application Ser. No. 13/440,612, filed Apr. 5, 2012, which is a continuation of U.S. application Ser. No. 12/218,151, filed on Jul. 11, 2008, which is now U.S. Pat. No. 8,177,536, issued May 15, 2012, which claims priority to and the benefit of U.S. Provisional Application No. 60/995,319, filed on Sep. 26, 2007. The disclosure of each of the above-referenced applications is hereby incorporated herein by reference in their entirety.
| Number | Name | Date | Kind |
|---|---|---|---|
| 3134600 | Fisch | May 1964 | A |
| 3357412 | Sabet | Dec 1967 | A |
| 5597168 | Antonini | Jan 1997 | A |
| 20090081063 | Kemp | Mar 2009 | A1 |
| Entry |
|---|
| Extended European Search Report issued on Oct. 19, 2015 for application EP 13755651.0, filed on Mar. 1, 2013 and published as EP 2820304 on Jan. 7, 2015 (Applicant—Torad Engineering, LLC // Inventor—Kemp, et al.) (7 pages). |
| First Office Action issued on Oct. 22, 2015 by the State Intellectual Property Office of the People's Republic of China for application CN 201380017773.4, filed on Jun. 1, 2014 and published as CN 104204527A on Dec. 10, 2014 (Applicant—Torad Engineering, LLC // Inventor—Kemp, et al.) (10 pages—original // 11 pages—translation). |
| Number | Date | Country | |
|---|---|---|---|
| 20150017046 A1 | Jan 2015 | US |
| Number | Date | Country | |
|---|---|---|---|
| 60995319 | Sep 2007 | US |
| Number | Date | Country | |
|---|---|---|---|
| Parent | 13440612 | Apr 2012 | US |
| Child | 14329402 | US | |
| Parent | 12218151 | Jul 2008 | US |
| Child | 13440612 | US |
