OPERATING THE SAME

TECHNICAL FIELD

The present invention relates broadly to a revolving vane compressor and to a method of operating a revolving vane compressor.

BACKGROUND

A typical revolving vane compressor comprises a rotor and a sleeve with different axes of rotation, forming eccentricity; and a single vane mounted to the sleeve, the vane capable of sliding in and out of a vane slot formed at the rotor. The rotating motion of the sleeve and rotor initiates suction, compression and discharge phases. Normally, a revolving vane compressor is driven by an external power source, e.g. an electric motor or an internal combustion engine. For example, WIPO Publication No. WO 2013/036203 A1 describes a revolving vane compressor comprising a single vane pivotably mounted to the sleeve. In such single-vane revolving vane compressor, the same pocket of compressible fluid typically completes suction, compression and discharge in two complete revolutions. Up to two pockets of compressible fluid may be present; thus, at a steady operating state, such single-vane revolving vane compressor provides one suction, one compression and one discharge per each complete revolution.

It has been noted that the single-vane revolving vane compressor as described in the above WIPO publication may emit heavy first-order noise during operation, especially when the compressor is rotating at a high angular velocity. This may be a drawback if the compressor is to be used in a quiet setting, e.g. in a refrigeration unit or an air-conditioning unit in a car or room. The noise emitted during operation may also increase the vibration of the compressor, which may not be desirable and may cause other problems such as mounting issues, wearing of parts in the compressors and reduced efficiency. A need therefore exists to provide a revolving vane compressor that seeks to address at least some of the problems above or to provide a useful alternative.

SUMMARY

According to a first aspect of the present invention, there is provided a revolving vane compressor comprising:

a tubular sleeve having a first rotational axis;

a rotor disposed within the sleeve, the rotor having a second rotational axis offset from the first rotational axis such that a channel is formed between the sleeve and the rotor;

a primary vane configured to mechanically connect the sleeve and the rotor such that the sleeve is operable to drive the rotor, and vice versa;

at least one secondary vane, the primary vane and the at least one secondary vane partitioning the channel into a plurality of chambers;

a plurality of suction ports, each associated with one of the plurality of chambers; and

a plurality of discharge ports, each associated with one of the plurality of chambers,

wherein each of the suction ports is operable to draw a first predetermined volume of a compressible fluid into its associated one of the plurality of chambers, each of the primary and secondary vanes is operable to compress the fluid in its associated one of the plurality of chambers to a second predetermined volume, and each of the discharge ports is operable to discharge the compressed fluid from its associated one of the plurality of chambers,thereby producing a plurality of discharges per each complete revolution of the rotor and sleeve; and

wherein the at least one secondary vane extends outwardly from the rotor relative to the second rotational axis, a first end of the at least one secondary vane being in sliding engagement with the rotor, and a second end of the at least one secondary vane abutting an inner wall of the sleeve.

At least one of the discharge ports and suction ports may be disposed on a circumferential surface of the rotor. At least one of the discharge ports and suction ports may be disposed on a circumferential surface of the sleeve. At least one of the discharge ports and suction ports may be disposed on an end face of the sleeve.

At least one of the discharge ports and suction ports may be disposed on an end face of the rotor.

Each of the plurality of chambers may be substantially fluid-tight relative to adjacent chambers.

The first end of the at least one secondary vane may be biased by biasing means.

The compressor may comprise a pressure difference between the first and second ends of the at least one secondary vane. A first end of the primary vane may be in sliding engagement with a shoe disposed in the rotor, and a second end of the primary vane may be fixedly mounted to the sleeve.

The shoe may be pivotable about a third rotational axis substantially parallel to the second rotational axis.

The primary vane and the at least one secondary vane may be disposed at substantially uniform angular distances about a circumference of the rotor. According to a second aspect of the present invention, there is provided an air-conditioning unit comprising the revolving vane compressor as defined in the first aspect. According to a third aspect of the present invention, there is provided a refrigeration unit comprising the revolving vane compressor as defined in the first aspect. According to a fourth aspect of the present invention, there is provided a method of operating a revolving vane compressor, the method comprising the steps of: partitioning a fluid channel of the revolving vane compressor into a plurality of chambers, the fluid channel being formed between a sleeve and a rotor of the compressor;

drawing a first predetermined volume of a compressible fluid into a first chamber of the plurality of the chambers;

compressing the fluid in the first chamber to a second predetermined volume; discharging the compressed fluid from the first chamber; and

repeating the drawing, compressing and discharging steps for each additional chamber of the plurality of the chambers, the compressor thereby producing a plurality of discharges per each complete revolution,

wherein the fluid channel is partitioned by a primary vane and at least one secondary vane, the at least one secondary vane extending outwardly from the rotor, a first end of the at least one secondary vane being in sliding engagement with the rotor, and a second end of the at least one secondary vane abutting an inner wall of the sleeve.

Partitioning the fluid channel of the revolving vane compressor into a plurality of chambers may comprise using a primary vane and at least one secondary vane.

Partitioning the fluid channel of the revolving vane compressor into a plurality of chambers may further comprise forming a fluid-tight separation between adjacent chambers. BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments of the invention will be better understood and readily apparent to one of ordinary skill in the art from the following written description, by way of example only, and in conjunction with the drawings, in which:

Figure 1 shows a schematic diagram illustrating a sectional view of a revolving vane compressor according to an example embodiment. Figure 2A shows a sectional view of the revolving vane compressor of Figure

1 when the primary vane is aligned with a reference line.

Figure 2B shows a sectional view of the revolving vane compressor of Figure 2A when the compressor is rotated clockwise by an angle of approximately 90° from the reference line.

Figure 2C shows a sectional view of the revolving vane compressor of Figure 2A when the compressor is rotated clockwise by an angle of approximately 1 80° from the reference line.

Figure 2D shows a sectional view of the revolving vane compressor of Figure 2A when the compressor is rotated clockwise by an angle of approximately 270° from the reference line. Figure 2E shows a sectional view of the revolving vane compressor of Figure

2A when the compressor is rotated clockwise by an angle of approximately 300° from the reference line.

Figure 3 shows a flow chart illustrating a method for operating a revolving vane compressor according to an example embodiment. DETAILED DESCRIPTION

Figure 1 shows a schematic diagram illustrating a sectional view of a revolving vane compressor 100 according to an example embodiment. The revolving vane compressor 100 comprises a sleeve 102, a rotor 104 disposed within the sleeve 102, a primary vane 106 and at least one secondary vane, represented in Figure 1 as secondary vane 108. The sleeve 102 in the example embodiment is a tubular sleeve having a first rotational axis 1 10, and the rotor 104 has a second rotational axis 1 12 offset from the first rotational axis 1 10. For example, the sleeve 102 and the rotor 104 are cylindrical and the rotor 104 has a smaller radius than the sleeve 102, such that a channel 1 14 is formed in the space between the sleeve 102 and the rotor 104. The primary vane 106 mechanically connects the sleeve 102 and the rotor 104 such that the sleeve 102 is operable to drive the rotor 104, and vice versa. The primary vane 1 06 and the at least one secondary vane 108 partition the channel 1 14 into a plurality of chambers, each of which is substantially fluid-tight from adjacent chambers. In the example shown in Figure 1 , the primary vane 1 06 and the secondary vane 108 divide the channel 1 14 into chambers 1 16, 1 1 8 respectively. The number of chambers may be increased by increasing the number of secondary vanes, and the noise generated by the compressor may change accordingly based on the number of chambers.

During operation of the compressor 100 of Figure 1 , a drive shaft (not shown) may rotate the sleeve 1 02, which, in turn, rotates the rotor 104. The volumes occupied by the chambers 1 16, 1 18 vary during the simultaneous rotational movement of the sleeve 1 02 and rotor 1 04. As a result, a compressible fluid may be independently drawn into each of the chambers 1 16, 1 18, and undergoes compression in the respective chambers 1 1 6, 1 18, before being discharged from the compressor 100. As the compressor 100 has a plurality of chambers 1 16, 1 18, a plurality of discharges may be produced per each complete revolution of the sleeve 102, as described in detail below with respect to Figures 2A-2E. In an alternate embodiment, the drive shaft may rotate the rotor 104, which, in turn, rotates the sleeve 102. The revolving vane compressor 100 further comprises means for drawing and discharging the compressible fluid, as described above, in the form of a plurality of suction ports and a plurality of discharge ports, schematically represented in Figure 1 as suction ports 120, 122 and discharge ports 124, 126. The suction ports 120, 122 and discharge ports 124, 126 may include valves which are operable to selectively open or close based on the status of the chamber 1 16, 1 18 connected thereto. For example, in Figure 1 , if the chamber 1 18 is in a suction phase (i.e. the compressible fluid is being drawn into the chamber 1 18), the suction port 122 is open. At the same time, if the chamber 1 16 is in a compression phase (i.e. the compressible fluid is being compressed), the suction port 120 and discharge port 124 are both closed. If there is a discharge, a discharge port, e.g. 126, is open and suction port 120 is closed.

The suction ports 120, 122 and discharge ports 124, 126 may be disposed at suitable locations, e.g. on a circumferential surface or end face, on the sleeve 102 and/or rotor 104. In the example shown in Figure 1 , the suction ports 120, 122 are formed in the sleeve 102, while the discharge ports 124, 126 are formed in the rotor 104, e.g. on a circumferential surface. In an alternate embodiment, the suction ports 120, 122 may be formed in the rotor 104, while the discharge ports 124, 126 are formed in the sleeve 102. In yet another embodiment, the suction ports 120, 122 and discharge ports 124, 126 may be formed exclusively in the sleeve 102, or exclusively in the rotor 104. Also, the suction ports 120, 122 and discharge ports 124, 126 may be formed along an axial direction of the sleeve 102 and rotor 104 in other embodiments. For example, the suction ports 120, 122 and discharge ports 124, 126 may be located on an end face (front or rear) of the sleeve 102 or rotor 104. It will be appreciated by a person skilled in the art that different permutations and combinations are possible, and the above- described configurations are some of the examples.

The revolving compressor 100 as described may be operable to rotate in a clockwise or anti-clockwise manner, and the arrangement, shaped and/or orientation of the suction and discharge ports may be changed accordingly. For example, with reference to Figure 1 , if the compressor 100 rotates clockwise and suction port 122 is formed on a circumference surface of the sleeve 102, the geometry of the suction port 122 may be adapted to enable smooth flow of the compressible fluid into the chamber Moreover, in the example shown in Figure 1 , the sleeve 102 is in the form of a hollow cylinder, the rotor 104 is also cylindrical and, the sleeve 102 and rotor 104 contact circumferentially with each other at a common point of tangency 128. The cylindrical shapes of the sleeve 102 and rotor 104 may provide a compact arrangement while ensuring even distribution of force during the rotational movement. Furthermore, the cylindrical shapes of the sleeve 102 and rotor 104 may simplify the manufacturing and assembly of the compressor 100. In alternate embodiments, it will be appreciated that the sleeve 102 and rotor 104 may be of other shapes. For example, in such embodiments, the sleeve may be elliptical while the rotor is cylindrical. Both the sleeve 102 and rotor 104 are typically made of a rigid material, e.g. steel, that can withstand rotational movements as well as the pressure built up by the compressible fluid inside the chambers 1 16, 1 18. The primary vane 106 in the example embodiment is also made of a rigid material and includes a first end 130 in sliding engagement with a shoe 132 disposed in the rotor 104, and a second end 134 fixedly mounted to the sleeve 102. The shoe 132 is pivotable about a third rotational axis substantially parallel to the second rotational axis 1 12. For example, the shoe 132 is disposed in a primary vane slot 136 formed in the rotor 104 that extends along a direction parallel to the second rotational axis 1 12. During operation of the compressor 100, as the sleeve 102 and rotor 104 rotate, the primary vane 106 can slide relative to the shoe 132, while the shoe 132 can pivot back and forth about its axis. The length of the primary vane 106 is sufficient to prevent the primary vane 106 from being dislodged from the primary vane slot 136 at any point during the rotational movement. The primary vane 106 can thus form a fluid barrier between chambers 1 16 and 1 18. In alternate embodiments, the primary vane 106 may be coupled to the sleeve 102 and rotor 104 via other mechanical means, as will be appreciated by a person skilled in the art. For example, the first end 130 of the primary vane 106 may be in sliding engagement with the primary vane slot 136, while the second end 134 is pivotably coupled to the sleeve 102.

As shown in Figure 1 , the secondary vane 108 extends outwardly from the rotor 104 relative to the second rotational axis 1 12. For example, the secondary vane 108 may extend radially outwardly from the rotor 104, or at an angle to the radial direction. In the latter case, the angle may be determined after taking into consideration the tangential force. A first end 138 of the secondary vane 108 is in sliding engagement with the rotor 104, while a second end 140 of the secondary vane 108 abuts an inner wall of the sleeve 102. For example, the secondary vane 108 may be disposed in a secondary vane slot 142 formed in the rotor 104 that extends outwardly relative to the second rotational axis 1 12. As the rotor 104 rotates, a centrifugal force generated by the rotational movement expels the secondary vane 108 outwardly along the secondary vane slot 142, such that the second end 140 maintains contact with the inner wall of the sleeve 102 even as the secondary vane 108 may slide along the inner wall of the sleeve 102. The length of the secondary vane 108 is sufficient to prevent the secondary vane 108 from being dislodged from the secondary vane slot 142 at any point during the rotational movement.

The abutment of the second end 140 against the sleeve 102 can prevent or substantially reduce leaking of the compressible fluid from a chamber 1 16, 1 18 to adjacent chambers, thereby forming a substantially fluid-tight separation between the chambers. In some embodiments, in addition to the centrifugal force, the abutment may be enhanced by biasing the first end 138 of the secondary vane 108 using biasing means, e.g. a spring, disposed in the secondary vane slot 142 to urge the secondary vane 108 outwardly of the secondary vane slot 142. In other embodiments, the abutment may be enhanced by maintaining a pressure difference between the first end 138 and second end 140 of the secondary vane 108 to similarly urge the secondary vane 108 outwardly of the secondary vane slot 142. In preferred embodiments, the primary vane 106 and the at least one secondary vane are disposed at substantially uniform angular distances about a circumference of the rotor 104. In other words, the maximum volumes that may be attained by the chambers 1 16, 1 18 partitioned by the primary vane 106 and the at least one secondary vane are approximately equal. This may help to ensure that the volume of fluid produced by each discharge stays relatively consistent. For example, in the example having one secondary vane 108 shown in Figure 1 , the secondary vane 108 is disposed substantially diagonally opposite the primary vane 106 relative to the second rotational axis 1 12. It will be appreciated that the angular distances between the primary vane 106 and the at least one secondary vane, as well as the number of secondary vanes and orientation of the secondary vanes may adjusted in alternate embodiments, depending on e.g. the desired cooling capacity, noise, power consumption and durability. In other words, the angular distances between the vanes may be non-uniform, and the secondary vanes may extend from the rotor at an angle to the radial direction.

In addition, it will be appreciated that the revolving vane compressor 100 may include other structural components, e.g. housing, a cylinder cover, mounting means, fluid inlet and outlet, etc., as described in WIPO Publication No. WO 2013/036203 A1 , the contents of which are hereby incorporated by cross reference. In some implementations, the moving parts of the compressor 100 may be mounted in a noise-absorbing or noise-cancelling housing that effectively forms a muffler.

With reference to Figures 2A-2E, an example steady-state operation of the revolving vane compressor 100 of Figure 1 is now described.

Figure 2A shows a sectional view of the revolving vane compressor 100 of Figure 1 when the primary vane 106 is aligned with a reference line 200 and the compressor 100 is rotating in a clockwise direction. At this position, the channel 1 14 is partitioned into a first chamber 202 and a second chamber 204, each filled with a compressible fluid, by the primary vane 106 and secondary vane 108. The first chamber 202 is substantially fluid-tight relative to the second chamber 204. The fluid in the first chamber 202 is undergoing compression, and both suction port 122 and discharge port 126 connected to the first chamber 202 are closed. Here, the secondary vane 108 forms a fluid barrier by maintaining sliding abutment with an inner wall of the sleeve 102, and helps to compress the fluid in the first chamber 202. In addition, suction port 1 20 connected to the second chamber 204 is open and compressible fluid is being drawn into the second chamber 204 via suction port 120. Discharge port 124 connected to the second chamber 204 is closed. Figure 2B shows a sectional view of the revolving vane compressor 100 of

Figure 2A when the compressor 100 is rotated clockwise by an angle of approximately 90° from the reference line 200. At this position, the channel 1 14 is partitioned into the first chamber 202, the second chamber 204 and a new third chamber 206 defined between the primary vane 106 and the common point of tangency 128. The chambers 202, 204, 206 are substantially fluid-tight from each other. The compressible fluid in the second chamber 204 undergoes compression after a first predetermined volume has been drawn, and both suction port 1 20 and discharge port 124 connected to the second chamber 204 are closed. The compressible fluid in the first chamber 202 has been compressed to a second predetermined volume. The discharge port 126 connected to the first chamber 202 is opened and the fluid is discharged from the first chamber 202. This is the first discharge by the compressor 100 from the initial position shown in Figure 2A. Further, suction port 122 connected to the third chamber 206 is opened and the compressible fluid is being drawn into the third chamber 206 via suction port 122.

Figure 2C shows a sectional view of the revolving vane compressor 1 00 of Figure 2A when the compressor 100 is rotated clockwise by an angle of approximately 180° from the reference line 200. At this position, the channel 1 14 is partitioned into the second chamber 204 and the third chamber 206 by the primary vane 106 and secondary vane 108. The compressible fluid in the second chamber 204 is undergoing compression, and both suction port 120 and discharge port 124 connected to the second chamber are closed. Here, the primary vane 1 06 forms a fluid barrier and helps to compress the fluid in the second chamber 204. In addition, suction port 122 connected to the third chamber 206 is opened and compressible fluid is being drawn into the third chamber 206 via suction port 122. Discharge port 126 connected to the third chamber 206 is closed.

Figure 2D shows a sectional view of the revolving vane compressor 1 00 of Figure 2A when the compressor 100 is rotated clockwise by an angle of approximately 270° from the reference line 200. At this position, the channel 1 14 is partitioned into the second chamber 204, the third chamber 206 and a new fourth chamber 208 defined between the secondary vane 108 and the common point of tangency 128. The chambers 204, 206, 208 are substantially fluid-tight from each other. The compressible fluid in the second chamber 204 is still undergoing compression, and the discharge port 1 24 connected to the second chamber 204 is closed. In addition, suction port 122 connected to the third chamber 206 is opened and the compressible fluid continues to be drawn into the third chamber 206 via suction port 122. Suction port 120 connected to the fourth chamber 208 is also opened and the compressible fluid starts to be drawn into the fourth chamber 208 via suction port 120.

Figure 2E shows a sectional view of the revolving vane compressor 100 of Figure 2A when the compressor 100 is rotated clockwise by an angle of approximately 300° from the reference line 200. At this position, the channel 1 14 is partitioned into the second chamber 204, third chamber 206 and fourth chamber 208, which are substantially fluid-tight from each other. The compressible fluid in the third chamber 206 undergoes compression after the first predetermined volume has been drawn, and both suction port 122 and discharge port 126 connected to the third chamber 206 are closed. The compressible fluid in the second chamber 204 has been compressed to the second predetermined volume. The discharge port 124 connected to the second chamber 204 is opened and the compressible fluid is discharged from the second chamber 204. This is the second discharge by the compressor 100 from the initial position shown in Figure 2A. Further, suction port 120 connected to the fourth chamber 208 is opened and the compressible fluid is being drawn into the fourth chamber 208 via suction port 120.

As described above with reference to Figures 2A to 2E, the compressor 1 00 can have suction phase, compression phase and discharge phase occurring simultaneously in different chambers when the compressor 100 rotates. In other words, each of the plurality of chambers of the compressor 100 may independently draw, compress and discharge the compressible fluid, thereby producing a plurality of discharges per each complete revolution. Also, in contrast to a conventional single-vane revolving compressor which allows only one suction phase and one discharge phase in one complete revolution during steady-state operation, the compressor 100 in embodiments of the present invention may have multiple suction phases and discharge phases in one complete revolution. For example, in the above example, two discharges are produced by first chamber 202 and second chamber 204, respectively, in one complete revolution of the compressor 100. Also, two new chambers 206, 208 are created and begin drawing the compressible fluid in the same revolution. Comparing the compressor 1 00 of the example embodiments with a conventional compressor having the same capacity and a single primary vane, the compressor 100 of the example embodiments discharge more frequently during one complete revolution. The duration of compression is relatively shorter than in a conventional single-vane revolving vane compressor. Therefore, compared to the conventional compressor, the heaviness of 1 ^st order pulse (i.e. noise) has been diminished and shifted towards a higher order. The number of peaks may increase and the durations of high pressure may be further shortened if more secondary vanes are used. In other words, the noise profile may be adjusted as desired. This can reduce the noise and vibration generated by the compressor 100 of the example embodiments during each cycle and render the compressor 1 00 to be more suitable for use in quiet settings, such as in a refrigeration unit or an air-conditioning unit.

Furthermore, the compressor 100 of the example embodiments may achieve superior performance compared to a conventional single-vane revolving vane compressor of a similar size as the compressor 100 of example embodiment discharges more compressible fluid per each complete revolution. Hence, the compressor 100 of the example embodiments can be advantageously compact, and can be physically smaller to deliver same displacement performance as a single-vane revolving vane compressor.

Figure 3 shows a flow chart 300 illustrating a method of operating a revolving vane compressor according to an example embodiment. At step 302, a fluid channel of the revolving vane compressor is partitioned into a plurality of chambers. At step 304, a first predetermined volume of a compressible fluid is drawn into a first chamber of the plurality of the chambers. At step 306, the fluid is compressed in the first chamber to a second predetermined volume. At step 308, the compressed fluid is discharged from the first chamber. At step 310, the drawing, compressing and discharging steps are repeated for each additional chamber of the plurality of the chambers, the compressor thereby producing a plurality of discharges per each complete revolution.

It will be appreciated by a person skilled in the art that numerous variations and/or modifications may be made to the present invention as shown in the specific embodiments without departing from the spirit or scope of the invention as broadly described. The present embodiments are, therefore, to be considered in all respects to be illustrative and not restrictive.