WO2022034532A1

WO2022034532A1 - Rotary vane device

Info

Publication number: WO2022034532A1
Application number: PCT/IB2021/057433
Authority: WO
Inventors: Philip Reuben NICHOLSON; Stephen Reuben NICHOLSON
Original assignee: Magnevane Portugal Lda.; PIENAAR, Danie
Priority date: 2020-08-12
Filing date: 2021-08-12
Publication date: 2022-02-17

Abstract

THIS invention relates to a rotary vane device and more particularly but not exclusively, to a rotary vane engine, pump or compressor. The invention also relates to a rotor assembly suitable for use in such a rotary vane device. The rotary device includes a housing having an air inlet and an air outlet, and a cylindrical rotor body rotatably locatable inside the housing, the cylindrical rotor body including a plurality of longitudinally extending receiving slots. A vane is slidingly locatable inside each receiving slot, with the vanes biased away from the cylindrical rotor. Compression spaces are defined between operatively inner ends of the vanes and the complementary receiving slots in which the vanes are located. The device is characterized in that at least one compression space is in flow communication with the air inlet and/or the air outlet of the housing.

Description

ROTARY VANE DEVICE

BACKGROUND TO THE INVENTION

THIS invention relates to a rotary vane device and more particularly but not exclusively, to a rotary vane engine, pump or compressor. The invention also relates to a rotor assembly suitable for use in such a rotary vane device.

Rotary vane devices such as engines, pumps and compressors are well known in the art. One common embodiment of this technology utilizes a rotor having a plurality of vanes extending radially outwardly from radial slots provided in the rotor body, with the vanes being radially displaceable relative to the rotor. More particularly, the vanes on a rotary vane device travel in and out of the rotor, and in particular in and out of the slots, as they move along the eccentrically configured interior wall of the housing of the rotor. Centrifugal force or springs are commonly used to urge the vanes towards or against the outer wall. In their extended state, these vanes adjust to the housing’s (or cylinder’s) profile while being driven by the rotor. The displaceable vanes, used in combination with a rotor mounted offset relative to a cylindrical housing in which it is located, result in the formation of varying volume chambers between the rotor and the housing, with the volume of a chamber changing as the rotor rotates relative to the housing.

Common uses for a rotary vane pump include hydraulic fluid compression and compressed air pumps, for example in aircraft or trucks. Small rotary vane pumps can also be used for drink dispensers, medical dispensing pumps, water pumps on marine engines, compressed air drills and many other applications. The materials used to make the pump and vanes can be modified for high-temperature industrial applications such as furnace air injection or engine turbocharging. Rotary vane pumps also work well as vacuum pumps for example in aircraft applications, laboratory vacuum systems, medical applications and also to evacuate and recover refrigerants from air conditioning systems. Rotary vane engines are also known in the art. In short, the applications of rotary vane devices are almost endless, and growing rapidly.

A good seal is required between the end of a displaceable vane and the housing surface in which the rotor is located (and against which the end of the displaceable vane abut) in order to maintain the efficiency of the rotary vane device. Centrifugal forces exerted on the vanes inherently contribute to ensure that a good and dynamic seal is formed between the end of a vane and an inner surface of a rotor housing. However, in some cases centrifugal forces are not sufficient, and it has accordingly been proposed to use springs to augment the outwardly directed bias of the rotating vanes. The downside of this approach is that springs wear over time, which adversely affects the performance and reliability of a rotary vane device incorporating spring driven vanes. In addition, it also complicates the maintenance of the device.

It has been proposed to use magnets instead of springs to provide the required bias. Although this works well, some shortcomings are associated with this solution in certain applications. For example, there is limited space to mount magnets in both the vanes of the rotor and the rotor body, and the maximum magnetic flux that can be obtained is therefore limited by the size and number of magnets that can be used due to geometrical constraints.

One way of overcoming this disadvantage is presented in the applicant’s copending application ZA2014/03295 entitled “Rotary Vane Device”, the contents of which is incorporated herein by reference. In this embodiment, rotor magnets are located in the body of the rotor adjacent the vanes, and not operatively below the vane slots as is known in prior art applications. It has also been proposed for the rotor magnets to be located in the hollow core of the rotor, thus allowing the use of more magnets, and hence increased flux. This concept is disclosed in the applicant’s patent application WO2016/157090 entitled “Rotary Vane Device”, the contents of which is incorporated herein by reference.

The above designs result in increased magnetic flux, but it would be even more beneficial if the vane bias could be further increased.

It is accordingly an object of the invention to provide a rotary device that will, at least partially, alleviate the above disadvantages.

It is also an object of the invention to provide a rotary device which will be a useful alternative to existing rotary devices.

It is a still further object of the invention to provide a rotor for use in a rotary device that will, at least partially, alleviate the above disadvantages.

It is another object of the invention to provide a rotor for use in a rotary device which will be a useful alternative to existing rotors. SUMMARY OF THE INVENTION

According to the invention there is provided a rotary device including: a housing having an air inlet and an air outlet; a cylindrical rotor body rotatably locatable inside the housing, the cylindrical rotor body including a plurality of longitudinally extending receiving slots; a plurality of vanes, wherein each vane is slidingly locatable inside a receiving slot, and wherein the vanes are biased away from the cylindrical rotor; and compression spaces defined between operatively inner ends of the vanes and the complementary receiving slots in which the vanes are located; characterized in that at least one compression space is in flow communication with the air inlet and/or the air outlet of the housing.

There is provided for the at least one compression space to be in flow communication with the air inlet and/or the air outlet by way of a compression space flow conduit.

For clarity, in this specification, the volume formed between an operatively inner end of a vane and a complementary receiving slot in which the vane is located will be referred to as the compression space. The volume of the compression space will vary as the rotor rotates, and as the vanes accordingly move in and out relative to the receiving slots.

There is provided for the rotor to have an inlet section, being a volume adjacent the rotor inlet, and an outlet section, being a volume adjacent the rotor outlet.

There is provided for the compression space to be in flow communication with the air inlet of the housing when a vane is located in the inlet section of the housing, and for the compression space to be in flow communication with the air outlet of the housing when a vane is located in the outlet section of the housing.

There is provided for the rotor to be configured in order for inlet air to flow into the compression space when a vane is located in an inlet section of the housing, thereby to urge the vane outwards.

There is provided for the rotor to be configured in order for air to flow from the compression space towards the air outlet when the vane is located in an outlet section of the housing, thereby to release air from the compression space and allowing the relevant vane to be displaced inwardly towards the core of the rotor.

In one embodiment, the housing includes at least one end cap, with the end cap having a first flow communication conduit for facilitating flow communication from the air inlet to the compression space. In a preferred embodiment, an end cap will be located at each end of the housing, and hence at each end of the rotor.

There is provided for the or each end cap to include a second flow communication conduit for facilitating flow communication from the compression space to the air outlet.

There is provided for the conduits to be in the form of grooves formed in the operatively inner surface of the end cap.

There is provided for each flow communication channel to include: a central section which is in flow communication with the compression space; and a distal section which is in flow communication with the central section of the groove and with the air inlet or the air outlet. The central section is preferably at least partially arcuate, and each central section of each groove is located in only one of the sections of the housing.

There is provided for the central section to be in flow communication with a plurality of, preferably two, compression spaces at any given position of the rotor relative to the rotor housing.

There is provided for the conduits to be provided in both end caps.

In another embodiment, there is provided for a conduit to extend through the body of the rotor between a bottom of a receiving slot and the outer surface of the rotor, in order for a flow passage to be defined between the outside of the rotor and the compression space inside the rotor.

There is provided for more at least one conduit, preferably two conduits, to be provided adjacent each receiving slot.

There is provided for the conduits to be angularly offset relative to the receiving slots.

There is provided for the vanes to be biased away from the cylindrical rotor by way of a magnet arrangement including vane magnets located in the vanes, and opposing rotor magnets located in the rotor. In a preferred embodiment, the rotor magnets are located at least partially inside a core of the rotor body.

BRIEF DESCRIPTION OF THE DRAWINGS

Two embodiments of the invention are described by way of non-limiting examples, and with reference to the accompanying drawings in which:

Figure 1 is an exploded perspective view of a rotor assembly for use in a rotary device in accordance with a first embodiment of the invention;

Figure 2 is an assembled perspective view of a rotary device of Figure 1 ;

Figure 3 is an exploded perspective view of the rotor and vanes of the rotor assembly of Figure 1 ;

Figure 4 is a plan view of an end cap of the housing of the rotor device of Figure 1 ;

Figure 5 is an end view of one of the end caps of Figure 4 located inside the housing, without the rotor being present;

Figure 6 is a cross-sectional side view of part of the rotary device;

Figure 7 is an end view of Figure 5 with the rotor included but shown in broken lines;

Figure 8 is a cross-sectional end view of the rotor device of Figure 2;

Figure 9 is an exploded perspective view of a rotor assembly for use in a rotary device in accordance with a second embodiment of the invention; Figure 10 is a cross-sectional side view of the rotor of the assembled rotor assembly of Figure 9; and

Figure 1 1 is a cross-sectional end view of the assembled rotor assembly of Figure 9.

DETAILED DESCRIPTION OF INVENTION

Referring to the drawings, in which like numerals indicate like features, a nonlimiting example of a rotary device in accordance with the invention is generally indicated by reference numeral 10.

The rotary device 10 comprises a rotor assembly 11 that is locatable inside a complementary rotor housing 12. The rotor assembly 11 is retained inside the rotor housing 12 by way of two rotor housing end caps 13.

The rotor assembly 1 1 comprises a rotor body 20 and a plurality of vanes 30 that displaceably (more particularly slidingly) extend from the rotor body. The rotor body 20 is of a cylindrical configuration, and is circular in cross section. The length and diameter of the body will depend on the cylinder capacity that is required for a particular application. A plurality of elongate receiving slots 22 are provided in the body, and extend generally parallel relative to a longitudinal axis of the cylindrical body. In this particular embodiment, six equally spaced apart receiving slots 22 extend radially outwardly from a center zone of the rotor body 20, thus dividing the rotor body 20 into six sectors. In the embodiment shown in the drawings the slots are not of constant depth, but each include a deeper proximal section 22.1 , and shallower distal sections 22.2 at the opposite ends of the proximal section 22.1 , as can be best seen in Figure 6. The transition of the deeper section 22.1 to the shallower sections 22.2 occurs gradually by way of a tapered or angled intermediate section 22.3. The shape of the vanes and the slots are of course not a limitation of this invention, and a varying profiled vane (as shown in the drawings) can for example be used in combination with a constant profile slot (not shown). In fact, the latter embodiment - where the ends of the vane and the bottom surface of the slot will therefore be of a diverging nature - will be beneficial in facilitating more efficient flow of air from and to compression spaces 37 as described in more detail below. It is also foreseen for the vane 30 be substantially rectangular, and for only very small corner sections of the vanes to be tapered / beveled in order to ease flow form the grooves into the compression space 37.

The rotor body 20 has a core 25 which may be at least partially hollow, and/or which may include two receiving pockets 24 located at opposite ends of the core 25. In the embodiment shown, the receiving pockets are in the form of conical apertures extending inwardly from distal ends of the core or central section of the rotor body 20 towards the proximal zone of the rotor body 20. In this embodiment, the receiving pockets 24 are in the form of two discrete apertures, but there is no reason why the pockets cannot be in the form of two suitably profiled end zones of an elongate, and at least partially continuous, hollow core.

The rotor body 20 is eccentrically locatable inside the housing 12, as shown in Figures 7 and 8. An axis of the rotor body 20 is therefore not aligned with a centerline of the housing 12. This is configuration is well known in the art, and is required in order to define different sections where vanes extend from the rotor body 20 to different extents. As illustrated in Figure 5, the housing 12 can broadly be divided into two sections, being an inlet section 15 that is in flow communication with, and located adjacent the inlet 14 of the housing, and an outlet section 17 that is in flow communication with, and located adjacent the outlet 16 of the housing 12. The inlet section 15 is essentially the section where the vanes 30 are in the process of being displaced outwardly from the rotor body 20 while the rotor rotates inside the housing 12, whereas the outlet section 17 is the section where the vanes 30 are displaced into the rotor body while the rotor rotates inside the housing 12.

End sections 80 are removably securable to the distal end zones of the rotor body 20. Each end section 80 includes a flange section 82 that in use abuts the end of the rotor body, and hence seals of the receiving pocket 24, and a shaft section extending from the flange section 82. There is provided for the flange 82 to have apertures 83 extending therethrough, and for complementary threaded apertures 26 to be provided in the rotor body 20, in order for the end sections 80 to be securable to the rotor body 20 by way of threaded securing means. It is convenient for the shaft of the rotary device 10 to be a separate removable component as opposed to being integrally formed with the rotor body 20, as this allows for the provision of receiving pockets having a diameter larger than the bore that can potentially be formed in the shaft had the rotor body 20 and shaft been an integral component. The invention is, however, not limited to this embodiment and will also find application when the rotor and shaft are integrally formed.

It should be noted that the receiving slots 22 do not extend all the way to the receiving pockets 24, but that bottom ends of the receiving slots 22 are separated from the receiving pockets 24 by wall section 28. The rotor body 20 is made from a non-ferrous material in order to reduce the effect of the body 20, and in particular the wall section 24, on the magnetic field and magnetic flux formed by the rotor magnets.

Rotor magnets 23 (meaning magnets located in the rotor) are located inside the core 25 of the rotor body 20. In this embodiment, a single rotor magnet 23 is located in each receiving pocket 24, with the rotor magnet 23 and the receiving pocket 24 being complementary configured and dimensioned in order for the rotor magnet 23 snugly to fit inside the receiving pocket 24. In this embodiment, each rotor magnet 23 is of a conical configuration. Each vane 30 is in the form of a body of material 31 configured and dimensioned to fit inside an elongate receiving slot 22. Vane magnets 33 (meaning magnets located in the vanes) are provided at the end zones of the vane that will in use be located inside the receiving slot 22. The vane magnets 33 are in the form of elongate cylindrical magnets that are, in this embodiment, circular in cross section. The vane magnets 33 are located in elongate receiving apertures formed in the body 31 of the vane.

The exact configuration of the vane magnets and the rotor magnets are not of a limiting nature insofar as the invention is concerned. Although the embodiment shown in the figures are beneficial, and corresponds to that disclosed in co-pending application ZA2019/04452 entitled “Rotary Vane Device” (the contents of which is incorporated herein by reference), it will be appreciated that other magnet configurations can also be employed, for example that shown in the applicant’s prior patent application WO2016/157090 entitled “Rotary Vane Device”, the contents of which is incorporated herein by reference.

Spaces or volumes between operatively inner ends 34 of the vanes 30 and bottoms 22.1 of the grooves 22 define compression spaces 37, the relevance of which will become clear below. The volume of these compression spaces are variable, and depends on the radially displaced position of each vane relative to the housing 12. The eccentricity between the rotor 20 and the housing 12 means that the vanes 30 are continuously displaced between retracted positions, where the volume of the compression spaces 37 is at a minimum, and extended positions, where the volumes of the compression spaces 37 is at a maximum. The magnet arrangement urges the vanes towards the extended positions while the rotor travels through the first half of its rotation relative to the housing, whereas the eccentric inner wall of the housing 12 forces the vanes 30 against the magnet bias back into the retracted positions during the second half of the rotation of the rotor relative to the housing. Although not described in the specification, the magnets can be replaced by other biasing means, for example springs, without departing from the spirit and/or the scope of this particular aspect of the invention.

With reference to Figures 4 to 8 (a first embodiment of the invention), a salient aspect of this invention is the provision of compression space conduits 90, 95 that serve to improve the performance of the rotary vane device. In the first embodiment of the invention the compression space conduits take the form of grooves formed in operatively inner surfaces of the end caps 13. A first conduit or groove 90 in use corresponds with the inlet section 15 of the housing 12, and brings the air inlet 14 (and therefore the inlet section 15) of the housing in flow communication with the compression spaces 37 behind vanes 30 that are located in the inlet section 15. A second conduit or groove 95 corresponds with the outlet section 17 of the housing

12, and brings the compression spaces 37 behind vanes 30 located in the outlet section 17 in flow communication with the air outlet 14 (and therefore the outlet section 17 of the housing). The purpose of the first groove 90 is supply compressed air to the compression spaces 37 in order to boost the outward bias of the vanes while the vanes are located in the inlet section 15, and the purpose of the second groove 95 is to allow the compression spaces to ventilate into the housing when the vanes are in the outlet section 17, so as to prevent air trapped in the compression spaces 37 from acting as a buffer against inward displacement of the vanes.

The conduits (90, 95) in the inlet and outlet sections are of the same configuration, but their functionality is inverted. Each groove (90, 95) includes a central section (91 , 96) and a distal section (92, 97). The central section (91 , 96) is of arcuate configuration, and curves about a central axis of the end cap at a constant radial distance from the center of the end caps

13. The radial distance is selected in order for the central section (91 , 96) to align with the bottom of the slots 22 provided in the rotor 20, and hence with the compression spaces 37. Air in the central section (91 , 96) will therefore be able to flow into the compression space 37 when the vane is located in the inlet section 15, and air trapped in the compression space 37 will be able to flow into the central section of the other groove when the vane is located in the outlet section 17. The central sections (91 , 96) of the grooves (90, 95) will, however, not be directly in flow communication with the inlet and outlet sections of the housing because the ends of the rotor will cover the central sections (91 , 96) of the grooves. For this reason, each groove also includes a distal section (92, 97) which extends radially outwardly from the central section (91 , 96) beyond a perimeter of the rotor 20, in order for ends of the distal sections (92, 97) to be in flow communication with the inlet 15 and outlet 17 sections of the housing 12. Figures 7 and 8 show the ends of the distal sections (92, 97) of the grooves protruding slightly beyond the periphery of the rotor 20. Each central section (91 , 96) is long enough to extend between two or three vanes 30, and hence their respective compression spaces 37.

The grooves (90, 95) are shown to be of a generally Y-shaped configuration, with the distal sections (92,97) extending from the central sections (91 , 96) at an acute angle. It will be appreciated that this particular, although beneficial, is not limiting, and a substantially-shaped configuration, where the distal sections (91 , 96) are more perpendicular relative to the central sections (91 , 96) will also suffice.

In use, as is best seen in Figure 8, compressed air enters the housing through the compressed air inlet 14, as indicated by arrow A. The compressed air enters the inlet section of the housing (which is the upper half of the internal volume of the housing in figure 8) and enters the first groove 90 through the distal section 92 as indicated by arrow B. From there the compressed air flows along the distal section 92 into the central section 91 of the groove 90. The air is dispersed along the central section 91 , presented by arrow C, from where it enters the compression spaces 37 behind the vanes 30. The high pressure air therefore fills these pockets, and urges the vanes towards a radially outward direction. As the rotor 20 rotates, the compression spaces 37 start to overlap the central section 96 of the second groove 95 (the lower groove in the figure), and air accordingly flows from the compression spaces 37 (which are now decreasing in volume) into the central section 96 of the second groove, as shown by arrow D. The central section 96 acts as a collecting header that collects the air, and which discharges the air through the distal section 97 of the groove 95, as indicated by arrow E. The air is therefore discharged into the outlet section 17 of the internal volume of the housing 12, and exits the housing through the outlet 16, as indicated by arrow F. In this way, the grooves serve to aid the vane bias while the vanes are located in the inlet section of the housing, and serves to ventilate the compression spaces 37 when the vanes are in the outlet section of the housing 12.

Another embodiment of the invention is described with reference to Figures 9 to 11. The components of the rotary device are generally the same, and are not described in detail. The difference compared to the first embodiment resides in the configuration of the conduits. In the embodiment, instead of having the arcuate conduits or grooves in the end covers of the rotor casing, compression space conduits 100 are provided in the rotor 20 itself (i.e. the conduits extends through the body of the rotor). One conduit 100 is associated with each slot 22, and more particularly brings a compression space 37 behind each vane 30 in flow communication with the internal volume of the housing. The conduits 100 are orientated at an angle of between 10 and 50 degrees relative to the slots 22, and the open end of each conduit will in use (when the rotor is rotating) trail the vane with which it is associated. The operational flow path is indicated by arrows A-B-C-D-E, and it will be readily apparent that the net effect achieved by this configuration is the same as described for the first embodiment - i.e. compressed air will flow from the inlet section of the housing into the compression spaces to urge the vanes outwardly when a vane is located in an inlet section of the housing, and the air in the compression space will then be ventilated from the compression space into the outlet section of the housing when the relevant vane is located in the outlet section.

The inventors foresee that this invention will improve the bias, and thus the sealing action, of the vanes during the first part of the rotational cycle of the rotor, whilst not impeding the retraction of the vanes during the second part of the rotational cycle of the rotor.

It will be appreciated that the above are only some embodiments of the invention and that there may be many variations without departing from the spirit and/or the scope of the invention.

Claims

CLAIMS:

1 . A rotary device including: a housing having an air inlet and an air outlet; a cylindrical rotor body rotatably locatable inside the housing, the cylindrical rotor body including a plurality of longitudinally extending receiving slots; a plurality of vanes, wherein each vane is slidingly locatable inside a receiving slot, and wherein the vanes are biased away from the cylindrical rotor; and compression spaces defined between operatively inner ends of the vanes and the complementary receiving slots in which the vanes are located; characterized in that at least one compression space is in flow communication with the air inlet and/or the air outlet of the housing.

2. The rotary device of claim 1 wherein the rotor has an inlet section, being a volume adjacent the rotor inlet, and an outlet section, being a volume adjacent the rotor outlet.

3. The rotary device of claim 2 wherein the compression space is in flow communication with the air inlet of the housing when a vane is located in the inlet section of the housing, and wherein the compression space is in flow communication with the air outlet of the housing when a vane is located in the outlet section of the housing.

4. The rotary device of claim 2 or 3 wherein the at least one compression space is in flow communication with the air inlet and/or the air outlet by way of a compression space conduit.

5. The rotary device of claim 4 wherein the housing includes at least one end cap, with the end cap having a first compression space conduit for facilitating flow communication from the air inlet to the compression space.

6. The rotary device of claim 5 wherein the housing includes a second compression space conduit for facilitating flow communication from the compression space to the air outlet.

7. The rotary device of any one of claims 5 or 6 wherein the conduits are in the form of grooves formed in the operatively inner surface of the end cap.

8. The rotary device of any one of claims 5 to 7 wherein each compression space conduit includes: a central section which is in flow communication with the compression space; and a distal section which is in flow communication with the central section of the groove and with the air inlet or the air outlet.

9. The rotary device of claim 8 wherein the central section is at least partially arcuate, and wherein each central section of each groove is located in only one of the sections of the housing.

10. The rotary device of claim 8 or 9 wherein the central section is in flow communication with a plurality of compression spaces at any given position of the rotor relative to the rotor housing.

1 1 . The rotary device of any one of claims 7 to 10 wherein the conduits are provided in both end caps.

12. The rotary device of claim 4 wherein the compression space conduit extends through a body of the rotor between a bottom of a receiving slot and the outer surface of the rotor, in order for a flow passage to be defined between the outside of the rotor and the compression space inside the rotor.

13. The rotary device of claim 12 wherein at least one conduit is provided adjacent each receiving slot.

14. The rotary device of claim 12 or 13 wherein the conduits are angularly offset relative to the receiving slots.

15. The rotary device of any one of the preceding claims wherein the vanes are biased away from the cylindrical rotor by way of a magnet arrangement including vane magnets located in the vanes, and opposing rotor magnets located in the rotor.