ROTARY MOTOR WITH INTEGRAL FLUID SEAL

Abstract

A rotary compressor or expander apparatus embodies a scaling solution that is based on the physical configuration of the leakage path and various of its features to substantially inhibit flow of fluid through the leakage path, with minimal leakage.

Claims

1-32. (canceled)

33. An apparatus comprising: a main rotor and a stator, the main rotor being rotatable against the stator about a main axis defining axial and radial direction, the main rotor and the stator having respective annular rotor face and annular stator face that face one another and define between them a confined annular space; and one or more auxiliary rotors fitted in said main rotor and rotatable about auxiliary axes parallel to said main axis, the rotations being synchronized and function jointly to compress, expand or pump a fluid within the confined annular space formed between the main rotor and the stator; and fluid leakage paths that are formed between congruent opposite faces of each two of the main rotors, the auxiliary rotor and the stator; characterized in that: physical configuration of at least one of said fluid leakage path is configured with an active sealing element obstructing flow of fluid through said path upon rotation, the active sealing element comprises an interrupted leakage path in which a proximal section of the fluid leakage path extending from within the confined annular space branches into two distal sections including (i) one or more auxiliary rotor-associated leakage paths, each extending in a general axial direction and formed between one of the auxiliary rotors and congruent surfaces of the first part, and (ii) a generally radially extending section of a stator-associated leakage path formed between a member of said stator and congruent surfaces of said main rotor.

34. The apparatus of claim 33, wherein said radially directed section is linked at its distal end to a distal section of the main rotor-associated leakage path that extends from said distal end in a general axial direction.

35. The apparatus of claim 33, wherein the auxiliary rotor-associated leakage paths and the distal section of the main rotor-associated leakage path are radially separated with respect to the main axis.

36. The apparatus of claim 33, comprising one or both of at least one of said projecting elements, being a circumferential radial projection, radially extending from the main rotor into and rotatable within a congruent receiving recess of the stator, defining a tortuous distal section the main rotor-associated fluid leakage path extending in a general radial direction and linked to one another by a section extending over a rim the at least one circumferential radial projection, and at least one auxiliary rotor projection, being a circumferential radial projection extending from the auxiliary rotor and rotatable within a congruent receiving recess of the stator, defining a tortuous auxiliary fluid leakage path with sections thereof defined about the circumferential radial projections.

37. The apparatus of claim 36, comprising at least one of said main rotor projection and at least one of said auxiliary rotor projection.

38. The apparatus of claim 36, wherein one or more of the circumferential radial projections have a tapering cross section extending from their base to a rounded tip.

39. The apparatus of claim 33, wherein the outer face of the main rotor's annular member has a general trajectory angled at about 80-81 with respect to the axis.

40. The apparatus of claim 33, wherein the auxiliary rotor-associated fluid leakage path has a proximal segment at said branching that defines a general trajectory away from the auxiliary axis.

41. The apparatus of claim 40, wherein the angle between said segment and said outer face is about 90.

42. The apparatus of claim 33, comprising one or more fluid seals in respective one or more of the distal sections of the fluid leakage paths.

43. The apparatus of claim 33, for use as one or both of a compressor or an expander.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0270] In order to better understand the subject matter that is disclosed herein and to exemplify how it may be carried out in practice, embodiments will now be described, by way of non-limiting example only, with reference to the accompanying schematic drawings, in which:

[0271] FIG. 1 is a partial isometric view of an apparatus in accordance with an embodiment of this disclosure with some portions of the stator being cut out for better view of the main rotor and two auxiliary rotors.

[0272] FIG. 2 is a cross-section through the auxiliary rotor with partial isometric view of the apparatus of FIG. 1.

[0273] FIG. 3 is an isometric view with a radial cut through the center of the recess that accommodates the auxiliary rotor of the apparatus of FIG. 1.

[0274] FIG. 4 shows the same isometric view after fitting of the auxiliary rotor.

[0275] FIG. 5 shows a radial cut through the apparatus of FIG. 1 at a portion between consecutive auxiliary rotors.

[0276] FIG. 6 is a similar view to that of FIG. 5 of an apparatus according to another embodiment.

[0277] FIG. 7 shows an apparatus according to another embodiment of this disclosure in an isometric and partial axial cut-out view.

[0278] FIG. 8 shows and isometric and partial axial cut-of view of apparatus according to another embodiment of this disclosure.

[0279] FIG. 9 shows and isometric and partial axial cut-of view of apparatus according to another embodiment of this disclosure.

[0280] FIG. 10 is an isometric and partial radial and axial cut-out view of an apparatus according to yet another embodiment of this disclosure.

[0281] FIG. 11 is an isometric view of an apparatus according to yet another embodiment of this disclosure, illustrating the gearing system.

DETAILED DESCRIPTION OF EMBODIMENTS

[0282] In the following description some illustrative and non-limiting embodiments will be described with reference to the annexed drawings.

[0283] In describing the different embodiments, use will be made with reference numerals where the first digit is an indicator of the consecutive number of the embodiment and the subsequent reference numerals relate to the element number. Thus, for example, element 102 relates to the stator of the apparatus of the first embodiment illustrated in FIGS. 1-5, while element 302 relates to the stator of the second embodiment illustrated in FIG. 6. In other words, elements that are numbered by the same reference numeral save for the first digit serve the same function. In describing the different embodiments, the description may skip elements that have already been described in connection with other embodiments and the reader is referred to the description of previously described embodiment for an understanding of the structure and/or function of such elements.

[0284] Reference is first made to FIGS. 1-5, where an apparatus 100 according to an embodiment of this disclosure is schematically illustrated in several views. Apparatus 100 includes a stator 102, a main rotor 104 and a plurality of auxiliary rotors 106 (6 auxiliary rotors in this exemplary embodiment; however the number of auxiliary rotors may be any number dictated by design and engineering considerations). The rotor is rotatable about a main axis, represented, in FIG. 1, by a dashed line 108. In this embodiment the rotor is encompassed within the stator. In other embodiments this may be reversed as illustrated below in FIG. 10. The stator 102 is illustrated in the drawing schematically as an annular ring. However, as can be appreciated the stator may also be embodied as a larger frame having any shape as dictated by engineering or other considerations. Similarly, the main rotor 104 is shown schematically as a rotating ring-like element. However, as can also be appreciated, this rotor may have a variety of other configurations, for example the hollow space within the rotor may be filled or the rotor may have an integral structure for connecting to an axle, etc.

[0285] In general, the apparatus may be configured to operate as a compressor, in which case the main rotor 104 may be coupled to a motor, e.g. an electric motor, or may be configured to operate as an expander, in which case the main rotor 104 may be coupled to an energy generator, e.g. an electric generator.

[0286] The stator 102 and the rotor 104 have respective annular stator face 110 and annular rotor face 112 that face one another and define between them a confined annular space 114 (best seen in FIGS. 3 and 5).

[0287] The plurality of auxiliary rotors 106 are embedded in a form-matching receiving recesses 116 (seen in FIG. 3) within the stator 102 that define a radial engagement sector between the auxiliary rotors and the main rotor. Each of the auxiliary rotors 106 is axially rotatable about an auxiliary axis, represented by a dashed line 118 in FIG. 4, that is parallel to the main axis 108 and configured to rotate in synchrony with the main rotor 102. The synchrony may be achieved through a gearing system, such as that shown in FIG. 11. The auxiliary rotors 106 have each an engaging portion 120 with an engaging abutment 122 that abuts into the confined annular space 114 and is configured to roll at close engagement over the annular rotor face 112, flanked by two annular recesses 123A,123B that are configured to closely engage with annular members 124A,124B that are formed on the two sides and define side walls of the confined annular space 114.

[0288] A plurality of projecting elements 126 (one of which is seen in FIG. 1) are disposed on said annular rotor face 112 and extend therefrom into the confined annular space 114 and rotatable with the main rotor 104 within the confine annular space. The projecting elements 126 are configured to closely engage the annular stator face 110 and to be closely received in an engaging groove 128 formed on the engaging abutment 122 of the auxiliary rotor 106. The projecting elements 126 define in their rotation, jointly with the engaging portions 120, transient and volume-changing compartments for fluid intake, compression, expansion or discharge, as known per se. As also known per se, the confined annular apace has ingress ports for introducing fluid into the confined annular apace and has egress ports for fluid discharge out of the confined annular apace; and has a valving arrangement to permit timely fluid charge and fluid discharge into and out of the confined annular apace through the respective ingress and egress ports.

[0289] Each of two annular members 124A,124B has a respective inner face 128A,128B defining side walls of the confined annular space 114. The outer faces 130A, 130B of respective annular members 124A,124B are longer than the inner faces and extend in a generally radial direction to face bases 132A,132B. The annular members 124A, 124B have peripheral arcuated faces 141A,141B, that, as generally explained above, exert, during their rotations centrifugal forces that lead to the deposit of a film at an apex thereof providing a seal that hinders and reduces leakage losses of fluid from within the confined annular chamber. This arcuated section is presented to be one having a semi-circular cross-section, but it may also have a cross section that defines part of an ellipse, a polygonal cross-sectional shape or generally the arcuated section may trace any kind of spline.

[0290] The bases 132A,132B are a first portion of a generally axially oriented fluid leakage path, which in this exemplary embodiment, is a tortuous path with generally radial sections defined by annular radial projections 134A,134B.

[0291] The apparatus 100 of this embodiment has a mirror symmetry about a plane normal to the axis 108 and that passes in the middle of the confined annular space 114 in between the two annular members 124A,124B. While a mirror symmetry of all functional elements of the apparatus (the functional elements comprising the rotors, portions of the stator that engage the rotors and the fluid leakage paths defined therebetween) is a typical case for engineering an apparatus according to this disclosure, and indeed all apparatuses exemplified herein have such a mirror symmetric design, such as mirror symmetry is not the exclusive manner of designing an apparatus according to this disclosure. For example, for various design and engineering considerations, the auxiliary rotors may not have a mirror symmetry, whereby the auxiliary rotor-associated leakage path on one side may be different than the other. By another example, the stator may have an overall non-symmetric design, e.g. in view of engineering consideration for coupling the apparatus to other extraneous elements. Additionally, the rotor may be coupled to a motor or a generator at one side which by itself induces an asymmetry (although the auxiliary rotors and the leakage paths, in such a case my still have a mirror-symmetric design).

[0292] In order to permit rotation of the rotating elements, there must be a clearance between the different elements and such clearance, as small as it is, would create a fluid leakage paths between congruent opposite faces formed between the main rotor and each auxiliary rotor, between the main rotor and the stator and between each of the auxiliary rotors and the stator. Such leakage path 140A, 140B are schematically marked by winding arrows in FIG. 5, showing the lateral flow direction of leaking fluid from within the confined annular space 114 towards the two sides 142A,142B of the apparatus. This fluid leakage path has a proximal section 141A,141B that passe over arcuated section 136A,136B. The rotor 104, rotating about the axis 108 generates centrifugal forces that cause fluid droplets and mists to accumulate at the apex of the arcuated section 136A,136B yielding the formation of a film that impedes flow of leaking fluid through the leakage path 140A,140B. The leakage path 140A,140B branches at into two distal sections relative to the branching point 154A,154B, these including a radially directed section 143A,143B that extends along the outer face 130A,130A and is link to a distal, generally axial tortuous section with generally radial section defined by and extending over the rims of annular radial projections 134A,134B. Similarly, as described above in connection with the proximal section 141A,141B, the centrifugal forces cause the generation of a film at the rim of annular radial projections 134A,134B impeding flow of leakage fluid through fluid leakage path 140A,140B. Thus, for fluid leakage path 140A,140B there are several active fluid scaling mechanisms operating together, one defined by the arcuated section 136A,136B, and the other by annular radial projections 134A,134B and one by the branching at branchpoint 154A,154B.

[0293] Auxiliary rotor-associated leakage paths 144A,144B extend in a general axial direction and formed between each one of the auxiliary rotors 106 and congruent surfaces of the stator 102. The auxiliary rotor-associated leakage paths 144A,144B extend along a tortuous path over a circumferential radial projection 146A,146B.

[0294] A main rotor-associated leakage path consisting of the proximal section 141A, 141B a radially directed section 150A,150B and a distal segment 152A,152B. The proximal section 141A,141B extends from the confined annular space 114 (not seen in FIG. 2 given where the cross-section was made) until the branch point 154A,154B in a general axial direction and is formed between said arcuated section 136A,136B and congruent faces of the stator. The radially directed section 150A,150B extends generally radially from the intersection 154A,154B and is defined by said outer face and the congruent surface of the stator. The distal segment 152A,152B extends in a general axial direction along a tortuous path over a circumferential radial projection 134A,134B between faces of the main rotor and congruent faces of the stator.

[0295] It is of note that the congruent face defining said proximal section 140A,140B of the main rotor-associated leakage path, as seen in FIG. 2, is that of recesses 123A,123B but this is only at this radial cross-sectional location where recesses 123A, 123B touch annular sections 136A,136B. In other radial locations the congruent opposite faces are those of the stator. It is also to be noted that in this cross-section the engaging abutment 122 closely engages the annular rotor face 112 while in other locations the engaging abutment 122 there is a clearance between the engaging abutment 122 and the annular rotor face 112, as can be seen, for example, in FIG. 5. This cross-section was chosen for illustrative consideration as it clearly shows all leakage paths. It should be noted, also, that the intersection, occurs along a distance that is defined by shoulders 158A,158B lateral to recesses 123A,123B.

[0296] In the embodiment of FIGS. 1-5 there is one (on each side) main rotor circumferential projection 134A,134B and one auxiliary rotor circumferential projection 146A,146B. In other embodiments there may be 2, 3 or even more such projections, being all of the same radial extension, being different to one another in their radial extension, two being of the same radial span and one being different, etc.

[0297] The main rotor circumferential projection 134A,134B and the auxiliary rotor circumferential projection 146A,146B have each a tapering cross section extending from their base to a rounded tip. While typical, this is not the exclusive configuration for such circumferential projection. Also, the rounded tip of the projections may assume a circular cross-section, an elliptical a polygonal or generally have that shape of any spline.

[0298] The radially directed section 150A,150B extends generally radially, albeit angled in a trajectory towards the main axis that is designed such that the difference in heat-induced radial to axial expansion will cause a minimal change in the width of the radially directed section, e.g. a change in width that is less than about 25% over the range of operating temperatures of the apparatus. The trajectory of said radially directed section 150A,150B defined by the relatively straight major portion of the outer face 130A,130B of annular member 124A,124B, in this embodiment is about 81.

[0299] As can be seen, the first segment 158A,158B of the auxiliary rotor-associated fluid leakage path 144A,144B that extends from intersection 154A,154B, defines a general trajectory away from the auxiliary axis 118. The angle between segment 158A,158B and said radially directed section 150A,150B is about 90.

[0300] As already briefly noted above, axial centrifugal forces, caused by increasing rotational speed at the rim of a circumferential radial projections or at the apex of the arcuated sections arcuated sections 136A,136B causes fluid-carried components, which may be one or more of droplets, mist or other particles carried by the leaking fluid, to accumulate at such apex or rim region. These components may accumulate at such apexes and causer the formation of a film at such locations.

[0301] The leakage paths may be configured such that the flow time of leaking fluid from the annular confined space has a travel time through the leakage path (for example, in consequence of the branching) that is longer than the time for pressure change in an angular portion of the confined annular space in consequence of rotation of the projecting elements in said space. The fluid leakage path may be designed to have an enlarged cross-section at a portion thereof opposite a ridge of a circumferential projection, by designing one or both of the congruent surfaces to have a small deviation from the general trajectory or designing one of the congruent surfaces to have a section that slightly deviates from full congruency. The change in width may cause reduction of pressure of the leaking fluid flowing in the fluid leakage path and a resulting slow-down in travel speed of leaking fluid in the fluid leakage path.

[0302] The branching at branch points 154A, 154B may cause the fluids to flow cyclically in the forward our counter direction between the branches causing the fluid with the leakage path to remain there neither escaping nor entering the confined annular space 114. The branching of the leakage paths at the branch points 154A,154B into the auxiliary rotor-associated leakage path 144A,144B and the radially directed section 150A,150B may also be designed to cause reduction of pressure and a resulting slow-down in travel speed of the leaking fluid in said auxiliary rotor-associated leakage path and said radially directed section. Additionally, a section of the auxiliary rotor-associated leakage path 144A,144B and/or the radially directed section 150A, 150B, typically a section close to the intersection 154A,154B, may have a three-dimensional surface structure that is configured to increase friction of the leaking fluid flowing in such section. This may be in the form of surface irregularities such as surface abrasion, small indentations or small projections. Such surface irregularities are usually at a sub-millimeter level.

[0303] FIG. 6 shows an apparatus 200 according to another embodiment of this disclosure where the fluid leakage path has an enlarged cross-section at a portion thereof 235,235B opposite a ridge of a circumferential projection 234A,234B. These portions of the leakage path with an enlarged cross-section, will cause a local reduction of the pressure of the leaking fluid flowing through the fluid leakage path, causing condensation and deposit of a fluid film at such a portion, that acts as a seal impeding flow of leaking fluid through the fluid leakage path.

[0304] FIG. 7 shows an apparatus 300 according to another embodiment of this disclosure. The main difference between apparatus 300 and apparatus 100 of FIGS. 1-5, being in that (1) rather than a single circumferential radial projection 146A,146B formed on auxiliary rotor 106 in apparatus 100, auxiliary rotor 306 of apparatus 300 has one major circumferential radial projection 346A,346B and three minor ones 347A,347B having a smaller radial span than that of the major circumferential radial projection 346A,346B, with an increasing radial span from that closest to circumferential radial projection 346A,346B to the most lateral one of the three; and in that (2) rather than a single circumferential radial projection 156A,156B formed on main rotor 104 in apparatus 100, main rotor 306 of apparatus 300 has three circumferential radial projections 357A,357B descending in their radial from the largest close to outer face 330A,330B to the more lateral ones.

[0305] FIG. 8 shows an apparatus 400 according to another embodiment of this disclosure. In apparatus 400 there are no circumferential radial projections on both the main rotor 404 and the auxiliary rotor 406. However, the branching of the proximal segment at leakage path at the branchpoint into two distal leakage paths that are distinct from one another, permit to fit a rotary seal 460A,460B at the end of the main rotor-associated leakage path to further seal this leakage path and thereby blocking passage of any remaining leaking fluid. Similarly rotary seals 462A,462B can also be fitted at the end of the auxiliary rotor-associated leakage path and seals this leakage path by impeding flow of any remaining leaking fluid through this leakage path and thereby blocking passage of any remaining leaking fluid.

[0306] FIG. 9 shows an apparatus 500 according to another embodiment of this disclosure. This apparatus has an overall design like that of the apparatus 100 of FIGS. 1-5 with added sealing elements 560A,560B and 562A,562B that are like the sealing elements of apparatus 400.

[0307] FIG. 10 shows an apparatus 600 according to another embodiment of this disclosure. Whereas in all previous embodiments described above the stator was the peripheral member and the rotor was encompassed within the stator, this is reversed in apparatus 600, namely the stator 602 is the inner of these two members and the rotor rotates about the stator.

[0308] Reference is now being made to FIG. 11, showing an apparatus 700 according to another embodiment of this disclosure. Twelve auxiliary rotors 706 are disposed in the stator 702. The main rotor 704 is coupled to a gear wheel 705 that is geared to the cogged end portion 707 of auxiliary rotor 706. Through such gearing the main rotor 704 and the auxiliary rotors 706 may rotate in a synchronous manner.