Fluid flow converter with interstage flow passage - Patents.com

Abstract

An apparatus (2) for converting rotation into a fluid flow and / or a fluid flow into rotation, the apparatus (2) comprising a first stage including a coiled fluid conduit (3) having an inlet (11) and an outlet (13), a first fluid separator (15) configured to receive batches of a first fluid and batches of a second fluid from the outlet (13) of the coiled fluid conduit (3) of the first stage and to separate the first and second fluids, a second stage including a coiled fluid conduit (7) having an inlet (17) and an outlet (19), and a first inter-stage flow path (21) connecting the first fluid separator (15) to the inlet (17) of the coiled fluid conduit (7) of the second stage for supplying the first fluid to the inlet (17) of the coiled fluid conduit (7) of the second stage.

Description

[Technical field]

[0001] The present invention relates to a device for converting rotation into a fluid flow, and to a device for converting a fluid flow into rotation. [Background technology]

[0002] It has long been known to pump water or compress air using devices that alternate between air and water in a coiled pipe and rotate it around a rotating shaft. Such devices have few moving parts and are considered relatively simple and reliable.

[0003] For example, U.S. Patent No. 5,399,633 discloses a device for pumping a fluid, the device comprising a tube of constant cross section wound multiple times around a cylindrical structure to form a cylindrical coil. One end of the coiled tube is connected to a hollow shaft of the device, and the other end of the coiled tube terminates at the outer periphery of the cylindrical structure and is open to the atmosphere. When the cylindrical structure is rotated, water and air alternately enter the open end of the tube and are conveyed up the hollow shaft.

[0004] Patent document 2 discloses a more energy efficient device, in which, according to an embodiment, one coiled fluid conduit (a pressure increase fluid conduit) is used to achieve a gradual increase in pressure of the first and second fluids, and one coiled fluid conduit (a pressure decrease fluid conduit) is used to return the first and second fluids while achieving a gradual decrease in pressure. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] UK Patent Application Publication No. 1427723 [Patent Document 2] International Publication No. 2016 / 080902

[0006] There still appears to be room for improvement. In particular, it would be desirable to provide more compact and / or energy efficient devices for converting rotation into fluid flow and / or converting fluid flow into rotation. Summary of the Invention [Problem to be solved by the invention]

[0007] In view of the above, it is an object of the present invention to provide improved conversion of rotation to fluid flow and / or fluid flow to rotation in a multi-stage device. [Means for solving the problem]

[0008] Therefore, according to a first aspect of the present invention, there is provided an apparatus for converting rotation to fluid flow comprising: a first stage, a coiled fluid conduit having an inlet for receiving a first fluid having a first density and a second fluid having a second density higher than the first density, and an outlet, the coiled fluid conduit arranged to transport batches of the first fluid and batches of the second fluid towards the outlet of the coiled fluid conduit as the coiled fluid conduit rotates about an axis of rotation, the coiled fluid conduit arranged to pressurize the first fluid and the second fluid to provide a pressure differential between the outlet and the inlet; and a first fluid separator configured to receive the batches of the first fluid and the batches of the second fluid from the outlet of the coiled fluid conduit and to separate the first fluid and the second fluid; and a second stage, a first fluid separator configured to receive the batches of the first fluid and the batches of the second fluid from the outlet of the coiled fluid conduit and to separate the first fluid and the second fluid. a second stage including a coiled fluid conduit having an inlet for pressurizing the first and second fluids to provide a pressure differential between the outlet and the inlet when the coiled fluid conduit rotates about an axis of rotation to transport batches of the first fluid and batches of the second fluid toward the outlet of the coiled fluid conduit; a second stage first fluid separator configured to receive batches of the first fluid and batches of the second fluid output from the outlet of the coiled fluid conduit of the second stage and separate the first and second fluids; and a first inter-stage flow path connecting the first fluid separator of the first stage to the coiled fluid conduit inlet of the second stage to supply the first fluid to the inlet of the coiled fluid conduit of the second stage. The second stage allows the first fluid to be pressurized to a higher pressure than is achievable in a single stage device.

[0009] A fluid is any substance that flows. Fluids therefore include, for example, gases, liquids, and solid particles suspended in a liquid to form, for example, a particle suspension that exhibits fluid behavior. The first and second fluids may be mutually immiscible. For example, the first fluid is preferably a gas, such as air, and the second fluid is preferably a liquid, such as water.

[0010] The coiled fluid conduit does not necessarily have to be a coiled tube, but can be configured in many other ways, so long as the fluid path is coiled.

[0011] As the coiled fluid conduit is rotated about its axis of rotation against a pressure head, the combined center of mass of the first and second batches of fluid shifts along the coiled fluid conduit in response to the gradually increasing pressure in the coiled fluid conduit. The shifted combined center of mass in the coiled fluid conduit imparts a torque to the coiled fluid conduit. To maintain rotation, a torque of opposite sign must be applied to the coiled fluid conduit that is greater than or equal to the torque induced by the shift in center of mass.

[0012] The present invention is based on the realization that a multi-stage device for converting rotation to / from fluid flow can be made more compact by increasing the overlap between the coiled fluid conduits of different stages of the device. The inventors further realised that this overlap can be increased by providing an interstage flow passage in fluid communication between the outlet of the coiled fluid conduit of one stage and the inlet of the coiled fluid conduit of the next stage, through which the first fluid (such as air) is fed. The inlet of the coiled fluid conduit of the next stage can be offset along the device such that the coiled fluid conduit of the next stage can substantially overlap the coiled fluid conduit of the previous stage. In comparison with the device of US Pat. No. 5,999,136, this means that a much more compact device can be realised while maintaining performance, which in turn means that a much higher power rating can be realised for a given device dimension, particularly the length of the device, which is usually a critical dimension in this type of device.

[0013] It should be noted that embodiments of the apparatus according to aspects of the invention provide selective passage of the first fluid from the first fluid separator to the inlet of the coiled fluid conduit of the second stage. In other words, substantially only the first fluid is passed from the first fluid separator to the inlet of the coiled fluid conduit of the second stage. The term "selective" means that the passage of the first fluid is preferential over the passage of the second fluid. For example, at least 80% of the total volume passed may be made up of the first fluid. Advantageously, the volume fraction may be greater than 90%.

[0014] Further, to provide desired compactness and energy efficiency, the first inter-stage flow path may be advantageously configured to supply the first fluid to the inlet of the coiled fluid conduit of the second stage without pressurizing the first fluid.

[0015] According to an embodiment, the first stage may advantageously further comprise a first stage intra-stage flow path connecting the first stage first fluid separator and the inlet of the coiled fluid conduit of the first stage to allow the second fluid separated by the first stage first fluid separator to be transported again towards the inlet of the coiled fluid conduit of the first stage. The first stage intra-stage flow path may directly or indirectly connect the first stage first fluid separator and the inlet of the coiled fluid conduit of the first stage, as long as the inlet is also configured to receive the first fluid. To receive the first fluid, the inlet of the coiled fluid conduit of the first stage may be arranged in direct contact with a source of the first fluid. In an example where the first fluid is air, the inlet of the coiled fluid conduit of the first stage may be in direct contact with the atmosphere during at least a first portion of the rotation of the coiled fluid conduit of the first stage around the rotation axis of the device. The second fluid may be supplied to the first stage coiled fluid conduit inlet via the first stage intra-stage flowpath substantially continuously or batchwise during a second portion different from the first portion of a rotation of the first stage coiled fluid conduit about the axis of rotation of the device. In another example, the first stage coiled fluid conduit inlet may receive the first and second fluids via a second fluid separator, which may be in fluid communication with the first stage coiled fluid conduit inlet, may be in fluid communication with the inter-stage flowpath, and may be in fluid communication with the device inlet for receiving the first fluid from a source of the first fluid.

[0016] The intra-stage flow path may advantageously be arranged to selectively return the second fluid from the outlet of the coiled fluid conduit of an equipment stage (first stage, second stage, etc.) towards the inlet of the coiled fluid conduit of the equipment stage. In other words, substantially only the second fluid may be returned from the outlet to the inlet of the coiled fluid conduit of the first stage. Selective return should be understood to mean that the return of the second fluid is prioritized over the return of the first fluid. For example, at least 80% of the total return volume may be made up of the second fluid. Advantageously, the volumetric proportion may be greater than 90%.

[0017] It should be noted that an intra-stage flow path is not required for operation of the device according to the present embodiment. The device can be used when it is not necessary to return the second fluid from the outlet of the coiled fluid conduit to the inlet. For example, the device can be placed in a reservoir having the second fluid, in which case it is not necessary to provide an intra-stage flow path for closed circuit operation with respect to the second fluid.

[0018] According to various embodiments, the device according to aspects of the present invention may advantageously be included in a conversion mechanism and further comprises a support structure for holding the device, wherein the vertical level of a centre of a circle formed by the inlet of the coiled fluid conduit of the first stage when the coiled fluid conduit of the first stage is rotated about the rotation axis is held higher than the vertical level of a centre of a circle formed by the outlet of the coiled fluid conduit of the first stage when the coiled fluid conduit of the first stage is rotated about the rotation axis, a vertical offset distance selected such that a pressure exerted by a fluid column of the second fluid having a height equal to the vertical offset distance substantially matches a pressure difference between the outlet and the inlet of the coiled fluid conduit of the first stage.

[0019] It should be noted that the inlet and / or outlet of the coiled fluid conduit may be located near or on the axis of rotation, such that the inlet / outlet of the coiled fluid conduit will rotate about a point that constitutes the center of a circle formed by the inlet / outlet of the coiled fluid conduit as the coiled fluid conduit rotates about the axis of rotation.

[0020] To transport the first fluid from the inlet to the outlet of the coiled fluid conduit of the first stage while maintaining a closed circuit operation with respect to the second fluid, the inventors have realized that it is desirable to arrange the coiled fluid conduit such that there is a vertical offset distance between the inlet and outlet levels. This allows the second fluid to flow back towards the inlet with substantially no resistance, converting the energy of the pressure difference between the outlet and the inlet into potential energy of the second fluid returned to the inlet. This improves energy efficiency. Furthermore, less tubing is required since the intrastage flow path can be made using significantly shorter fluid conduits compared to the device of US Pat. No. 5,999,333. In an embodiment, the intrastage flow path may be straight. By using less tubing for the return of the second fluid from the outlet to the inlet, the device can also be made significantly more compact for a given output, at least during transport to the installation site.

[0021] For an optimum tradeoff between energy efficiency and conversion mechanism design considerations, it has been found to be beneficial to configure the support mechanism to hold the first stage coiled fluid conduit such that the axis of rotation is inclined at an angle in the range of 35° to 65° relative to the horizontal. In theory, a larger angle would increase energy efficiency, but the inventors have found that it is difficult to reliably form and maintain the batches of first and second fluids required to build up pressure along the coiled fluid conduit at angles greater than about 65°.

[0022] According to a second aspect of the present invention, there is provided an apparatus for converting a fluid flow into rotation about an axis of rotation, the apparatus comprising: an apparatus inlet for receiving a pressurized first fluid in gaseous form having a first density; an apparatus outlet (29) for discharging the depressurized first fluid from said apparatus (2); a first stage, a coiled fluid conduit adapted to depressurize said first and second fluids as said coiled fluid conduit rotates about said axis of rotation to alternately transport batches of said first fluid and batches of a second fluid in liquid form having a second density higher than said first density from said inlet to said outlet of said coiled fluid conduit in fluid communication with said apparatus inlet while providing a pressure differential between said outlet and said inlet; and a first fluid separator configured to receive batches of said first fluid and batches of said second fluid output from said outlet of said coiled fluid conduit of said first stage and to separate said first and second fluids. a first stage including a first fluid separator arranged to separate the first and second fluids from the first and second fluids; a second stage including a coiled fluid conduit adapted to transport alternate batches of the first and second fluids from an inlet to an outlet while reducing pressures of the first and second fluids to provide a pressure differential between the outlet and the inlet as the coiled fluid conduit rotates about the axis of rotation; and a first fluid separator arranged to separate the first and second fluids from the first and second fluids from the second fluid conduit while reducing pressures of the first and second fluids as the coiled fluid conduit rotates about the axis of rotation. a second stage including a first fluid separator of the second stage configured to receive the batches of the first fluid and the batches of the second fluid output from the outlet of conduit (7) and separate the first fluid and the second fluid; and a first inter-stage flow path connecting the first fluid separator of the first stage with the inlet of the coiled fluid conduit of the second stage for supplying a first fluid to the inlet of the coiled fluid conduit of the second stage.

[0023] It should be noted that the device for converting rotation to fluid flow according to the first aspect of the invention and the device for converting fluid flow to rotation according to the second aspect of the invention may be realised using the same structure. For example, the device may have two modes of operation, one for converting rotation to fluid flow and one for converting fluid flow to rotation. In this case, the direction of rotation in the second mode will be opposite to that in the first mode, the outlet in the first mode will be the inlet in the second mode, the first stage in the first mode will be the last stage in the second mode, etc. Furthermore, in a multi-stage device, the first stage in the first mode will be the last stage in the second mode, the second stage in the first mode will be the penultimate stage in the second mode, etc.

[0024] In summary, according to various embodiments, the present invention relates to an apparatus for converting rotation to fluid flow and / or fluid flow to rotation, the apparatus comprising a first stage including a coiled fluid conduit having an inlet and an outlet, a first fluid separator configured to receive batches of a first fluid and batches of a second fluid from the outlet of the coiled fluid conduit of the first stage and separate the first and second fluids, a second stage including a coiled fluid conduit having an inlet and an outlet, and a first inter-stage flowpath connecting the first fluid separator to the inlet of the coiled fluid conduit of the second stage for providing the first fluid to the inlet of the coiled fluid conduit of the second stage.

[0025] These and other aspects of the invention will now be described in more detail with reference to the accompanying drawings, in which exemplary embodiments of the invention are shown. [Brief description of the drawings]

[0026] [Figure 1] FIG. 1 is a schematic perspective view of a conversion mechanism according to an exemplary embodiment of the invention in the form of a multi-stage conversion mechanism having two modes of operation, namely, a mode in which the conversion mechanism converts rotation to fluid flow and a mode in which the device converts fluid flow to rotation. [Diagram 2] FIG. 2 is a simplified, partially disclosed schematic diagram of the mechanism of FIG. 1 when in operation to convert rotation into fluid flow. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0027] DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS In this detailed description, various embodiments of the apparatus and methods according to the present invention will be described primarily with reference to conversion mechanisms and devices that convert rotation to fluid flow and / or fluid flow to rotation using air as a first fluid and water as a second fluid.

[0028] It should be noted that this is not intended to limit the scope of the invention, which similarly includes devices that operate using other combinations of first and second fluids, for example having different densities, and operation using more than two different fluids is also envisaged.

[0029] 1 illustrates, diagrammatically, a conversion mechanism 1 according to an exemplary embodiment of the present invention in the form of a compressor / air motor 2. The compressor / air motor 2 is a device capable of operating in two operational modes: a first mode in which rotation is converted into fluid (air) flow, and a second mode in which a pressurized fluid (air) flow is converted into rotation.

[0030] The first operating mode mentioned above is described in detail herein. The second operating mode mentioned above involves operating the device "in reverse" compared to the first operating mode, i.e. the "inlet" in the first mode becomes the "outlet" in the second mode and vice versa. This also means that an electric motor (not shown in FIG. 1 ) arranged to rotate the device 2 in the first operating mode may act as a generator in the second operating mode, converting the rotation into electrical power.

[0031] The conversion mechanism 1 of FIG. 1 comprises the device 2 and a support structure 5 described above. The device 2 comprises a first stage including a coiled fluid conduit 3 of the first stage, a second stage including a coiled fluid conduit 7 of the second stage, and a third stage including a coiled fluid conduit 9 of the third stage. The support structure 5 holds the device 2 such that the inlet of the coiled fluid conduit 3 of the first stage is higher than the outlet of the coiled fluid conduit 3 of the first stage (first operating mode "compressor mode"). In a second operating mode ("air motor mode"), the first stage includes the coiled fluid conduit 9 that was in the third stage for the first operating mode, the second stage includes the coiled fluid conduit 7 that was in the second stage for the first operating mode, and the third stage includes the coiled fluid conduit 3 that was in the first stage for the first operating mode. As shown diagrammatically in FIG. 1, each stage may in embodiments actually be composed of multiple coiled fluid conduits each having an inlet and an outlet that are angularly spaced from one another. This configuration provides a more uniform flow of the first and second fluids in time.

[0032] FIG. 2 is a simplified, partially disclosed schematic diagram of the conversion mechanism 1 of FIG. 1 in operation to convert rotation into a fluid flow, in this example used as a compressor.

[0033] As discussed above in connection with FIG. 1, the first stage of the apparatus 2, when operating in a first mode of operation, comprises a first stage coiled fluid conduit 3 (only one first stage coiled fluid conduit 3 is shown in FIG. 2). The first stage coiled fluid conduit 3 has an inlet 11 and an outlet 13, and the apparatus 2 comprises a first stage first fluid separator 15 in fluid communication with the outlet 13. As discussed above in connection with FIG. 1, the second stage of the apparatus 2 comprises a second stage coiled fluid conduit 7. The second stage coiled fluid conduit 7 (only one second stage coiled fluid conduit 7 is shown in FIG. 2) has an inlet 17 and an outlet 19. The apparatus 2 further comprises a second stage first fluid separator 16 and a first inter-stage flow path 21 fluidly connecting the first stage first fluid separator 15 and the inlet 17 of the second stage coiled fluid conduit 7.

[0034] The first interstage flow passage 21 passes the pressurized first fluid (air) output from the outlet 13 of the coiled fluid conduit 3 of the first stage to the inlet 17 of the coiled fluid conduit 7 of the second stage. By arranging the first interstage flow passage 21 such that the inlet 17 of the coiled fluid conduit 7 of the second stage is offset along the axis of rotation 23 of the device 2 towards (and in this case beyond) the inlet 11 of the coiled fluid conduit 3 of the first stage, the device 2 can be made significantly more compact, at least in its longitudinal direction, than prior art multi-stage devices. It should be noted that the first interstage flow passage 21 can advantageously be configured to supply the first fluid (air) to the inlet 17 of the coiled fluid conduit 7 of the second stage without pressurizing (or depressurizing) the first fluid (air). This allows the use of a simple and compact configuration for the first interstage flow passage 21 (and optionally subsequent interstage flow passages). For example, the first interstage flow passage 21 may be configured as a simple straight pipe, as shown diagrammatically in the example configuration of FIG.

[0035] By providing an interstage flow passage 21 that selectively supplies a pressurized first fluid (air) from the outlet of the coiled fluid conduit of one stage to the inlet of the coiled fluid conduit of the next stage without any further pressure increase, the coiled fluid conduits of different stages of the device can be substantially completely overlapped, as shown diagrammatically in Figures 1 and 2. This allows a more compact multi-stage machine to be realized than that described in US Patent No. 5,999,333.

[0036] In the example configuration of Figure 2, the apparatus 2 is shown to further include a first stage intra-stage flow passage 25 connecting the first fluid separator 15 of the first stage with the inlet 11 of the coiled fluid conduit 3 of the first stage. In the example configuration of Figure 2, the first stage intra-stage flow passage 25 extends within a first coil formed by the coiled fluid conduits 3 of the first stage and within a second coil formed by the coiled fluid conduits 7 of the second stage, thereby realizing a compact apparatus 2. The first inter-stage flow passage 21 also extends within a first coil formed by the coiled fluid conduits 3 of the first stage and within a second coil formed by the coiled fluid conduits 7 of the second stage.

[0037] Additionally, in the exemplary configuration shown in Figure 2, the apparatus includes a first stage second fluid separator 27 in fluid communication with the inlet 11 of the first stage coiled fluid conduit 3, and an apparatus inlet 29 for receiving air from the atmosphere. In Figure 2, the first stage second fluid separator 27 is further shown in fluid communication with an outlet of the first stage intra-stage flow passage 25.

[0038] As can be easily understood, each turn / coil of the first stage fluid conduit 3 (as well as the second stage fluid conduit 7 and the third stage fluid conduit 9) is partially filled with a first fluid (air) in gaseous form and partially filled with a second fluid (water) in liquid form. In particular, the lower portion of each turn / coil is filled with the second fluid (water). When the device 2 is in operation, a batch of the first fluid (air) and a batch of the second fluid (water) are transported towards the outlet 13 of the first stage coiled fluid conduit 3, pressurizing the first fluid (air) and the second fluid (water), providing a pressure difference ΔP between the outlet 13 and the inlet 11 of the first stage coiled fluid conduit 3. As described in detail in U.S. Patent No. 5,399,992, which is incorporated herein by reference in its entirety, the rotation of the first stage coiled fluid conduit 3 about the rotation axis 23 offsets the vertical position of the second fluid (water) in each turn / coil due to pressure build-up in the first stage fluid conduit 3.

[0039] As described above, the pressurized first fluid (air) is routed from the first fluid separator 15 of the first stage via the first interstage flow path 21 to the inlet 17 of the coiled fluid conduit 7 of the second stage. The first fluid (air) is then further pressurized / compressed, e.g., during transport through the coiled fluid conduit 7 of the second stage.

[0040] The support structure 5 of the conversion mechanism 1 (omitted in FIG. 2 for clarity) holds the device 2 such that a first vertical level h1 of a center 31 of a circle formed by the inlet 11 when the first stage coiled fluid conduit 3 is rotated about the axis of rotation 23 is higher than a second vertical level h2 of a center 33 of a circle formed by the outlet 13 when the first stage coiled fluid conduit 3 is rotated about the axis of rotation 23. The difference between the first vertical level h1 and the second vertical level h2 (vertical offset distance Δh) is selected to be of a magnitude such that the pressure exerted by a fluid column of a second fluid (water in the exemplary case of FIG. 2) having a height equal to the vertical offset distance Δh substantially matches the pressure difference ΔP between the outlet 13 and the inlet 11 of the first stage coiled fluid conduit 3. It should be noted that the height of the fluid column of the second fluid actually present in the intra-stage flow passage 25 need not be equal to the vertical offset distance Δh, but may deviate somewhat from the vertical offset distance Δh, depending on the exact configuration of the apparatus 2 and / or the properties (e.g., density) of the first and second fluids used in the apparatus 2. For example, in the exemplary configuration of the apparatus 2 of FIG. 2, it can be seen that the level of the second fluid in the first fluid separator 15 does not exactly coincide with the aforementioned center 33 of the circle formed by the outlets 13 when the coiled fluid conduit 3 is rotated about the axis of rotation 23. It can also be seen that the level of the second fluid in the second fluid separator 27 of the first stage does not exactly coincide with the aforementioned center 31 of the circle formed by the inlets 11 when the coiled fluid conduit 3 is rotated about the axis of rotation 23. In the exemplary configuration of the conversion mechanism 1 of Figure 2, the height of the fluid column of the second fluid actually present in the intra-stage flow passage 25 is determined by the difference in height between the level of the second fluid in the second fluid separator 27 and the level of the second fluid in the first fluid separator 15, which differs somewhat from the vertical offset distance Δh described above. The difference between the actual fluid column height and the vertical offset distance Δh depends on a variety of factors, including the ratio of the first and second fluids that are set to be fed in batches to the inlet 11 of the coiled fluid conduit 3 of the first stage, and the inclination of the axis of rotation 23. This difference is expected to be on the order of ±10% at most.It is therefore believed that the vertical offset distance Δh is selected so that the pressure exerted by a fluid column of the second fluid having a height equal to the vertical offset distance Δh substantially matches the pressure difference between the outlet 13 and inlet 11 of the first stage coiled fluid conduit 3, i.e. has a magnitude within ±10%.

[0041] The pressure difference ΔP transports the second fluid (water in this case) separated by the first fluid separator 15 of the first stage through the intra-stage passage 25 of the first stage toward the inlet 11 of the coiled fluid conduit 3 of the first stage with almost no flow resistance. During passage through the intra-stage passage 25, the second fluid (water) is decompressed and the energy of the pressure difference ΔP is converted into an increase in potential energy substantially proportional to the vertical offset distance Δh (e.g., within ±10%, as explained above). This configuration improves the energy efficiency of the closed-loop return of the second fluid (water) within the first stage of the apparatus 2. Although the closed-loop return of the second fluid (water) has been described in detail only for the first stage of the apparatus 2, it will be apparent to one skilled in the art that the same principles also apply to the closed-loop return of the second fluid (water) in additional stages (in the case of a multi-stage apparatus) of the apparatus 2.

[0042] In this context, it should be mentioned that the fluid column and the pressure difference ΔP of the second fluid in the device 1 do not need to be precisely adjusted to each other to achieve improved energy efficiency with respect to prior art solutions. For example, the pressure difference ΔP may exceed the counter pressure of the fluid column in the intra-stage flow path 25, so that a residual overpressure exists at the outlet of the intra-stage flow path 25 (e.g., where the intra-stage flow path 25 enters the second fluid separator 27). Alternatively, the pressure difference ΔP may be insufficient to independently transport the second fluid (water) from the first fluid separator 15 to the inlet 11 of the coiled fluid conduit 3 of the first stage. In that case, the device 2 may be provided with an auxiliary flow path device, such as a small impeller.

[0043] 2, the rotating shaft 23 is illustrated as being inside the first stage coiled fluid conduit 3, which is coiled around the rotating shaft 23, the second stage coiled fluid conduit 7 is illustrated as being inside, and so on. While this may provide a simpler and more compact device 2, it should be noted that the device 2 could also operate with the rotating shaft 23 outside the first stage coiled fluid conduit 3 (as well as outside one or more of the second stage coiled fluid conduit 7 and third stage coiled fluid conduit 9).

[0044] As seen in Figure 2, the multi-stage apparatus 2 may further include an intra-stage flow path 30 of the second stage. In the example configuration of Figure 2, as described above for the first stage, the apparatus may further include a second stage second fluid separator 32 in fluid communication with the inlet 17 of the coiled fluid conduit 7 of the second stage, the outlet of the intra-stage flow path 30 of the second stage, and the outlet of the first inter-stage flow path 21. As described above in connection with the description of the first stage, the provision of the second stage second fluid separator 32 may be beneficial in certain applications and may facilitate the design of a relatively compact apparatus 2. However, it should be noted that it is also possible to design the apparatus 2 to function without the second stage second fluid separator 32.

[0045] When the apparatus 2 operates in the first operating mode, the first interstage flow path 21 selectively supplies pressurized first fluid (air) from the outlet 13 of the first stage coiled fluid conduit 3 to the inlet 17 of the second stage coiled fluid conduit 7 without further pressure increase.

[0046] In the exemplary arrangement shown in Figure 2, the apparatus 2 comprises a third stage including a third stage coiled fluid conduit 9 as described above (only one third stage coiled fluid conduit 9 is shown in Figure 2). With reference to Figure 2, the third stage coiled fluid conduit 9 has an inlet 35 for receiving a first fluid (air) and a second fluid (water), and an outlet 37. As described above with reference to the first stage coiled fluid conduit 3, the third stage coiled fluid conduit 9 is arranged to transport batches of the first fluid (air) and batches of the second fluid (water) towards the outlet 37 whilst pressurising the first fluid (air) and the second fluid (water).

[0047] As seen in FIG. 2, the multi-stage apparatus 2 further comprises a third stage first fluid separator 39, a third stage interstage flow path 43, and a first interstage flow path 33 connecting the second stage first fluid separator 16 to the third stage coiled fluid conduit 9 inlet 35 for supplying a pressurized first fluid (air) to the third stage coiled fluid conduit 9 inlet 35. In the example configuration of FIG. 2, as described above for the first stage, the apparatus may further comprise a third stage second fluid separator 45 in fluid communication with the third stage coiled fluid conduit 9 inlet 35, the third stage intrastage flow path 41 outlet, and the second interstage flow path 43 outlet. As described above in connection with the description of the first stage, the provision of the third stage second fluid separator 45 may be beneficial in certain applications and may facilitate the design of a relatively compact apparatus 2. However, it should be noted that it is possible to design an apparatus that functions without the third stage second fluid separator 45.

[0048] When the apparatus 2 operates in the first operating mode, the second interstage flow path 43 selectively supplies pressurized first fluid (air) from the outlet 31 of the coiled fluid conduit 7 of the second stage to the inlet 35 of the coiled fluid conduit 9 of the third stage without any further pressure increase.

[0049] Following the pressure increase provided by the third stage coiled fluid conduit 9, as described above for the first stage coiled fluid conduit 3, the pressurized first fluid becomes available at the device outlet 47 via the fluid flow in conduit 49 connecting the third stage first fluid separator 39 and the device outlet 47.

[0050] In FIG. 2, the intra-stage and inter-stage flow paths are illustrated as straight pipes extending parallel to the axis of rotation 23 of the device 2 along substantially the entire length of the intra-stage and inter-stage flow paths inside the first coil formed by the coiled fluid conduits 3 of the first stage. It should be noted that the intra-stage and inter-stage flow paths may be provided in different configurations. For example, all or a portion of the intra-stage and inter-stage flow paths may extend partly inside and partly outside the first coil, such as inside the first coil for a first portion of the entire distance along the intra-stage or inter-stage flow path and outside the first coil for a second portion of the entire distance. For example, the first inter-stage flow path may extend at least partly inside and partly outside the first coil. This configuration may facilitate the manufacture and maintenance of the device 2 according to some configurations. Additionally, at least a portion of the intra-stage and / or inter-stage flow paths may be coaxial with the axis of rotation 23 along at least a portion of the total length of the intra-stage or inter-stage flow paths. This configuration makes it possible to provide a more compact device 1, especially with regard to the dimensions perpendicular to the axis of rotation 23.

[0051] In the case of a multi-stage device, as shown diagrammatically for the device illustrated in Figures 1 and 2, the coiled fluid conduit 7 of the second stage may be radially inward of the coiled fluid conduit 3 of the first stage (or the coiled fluid conduit 9 of the third stage may be radially inward of the coiled fluid conduit 7 of the second stage, etc.). This may facilitate easier manufacture of the device, as the large volume of first fluid (air) in the first stage will benefit from the coiled fluid conduit 3 having a larger internal cross section.

[0052] As also shown diagrammatically in Figures 1 and 2, the distance along axis of rotation 23 between inlet 11 and outlet 13 of coiled fluid conduit 3 of the first stage may be less than the distance along axis of rotation 23 between inlet 17 and outlet 19 of coiled fluid conduit 7 of the second stage, which may be less than the distance along axis of rotation 23 between inlet 35 and outlet 37 of coiled fluid conduit 9 of the third stage, and so on. This is particularly advantageous in embodiments where the first fluid is a compressible gas, such as air in the apparatus 2 of Figures 1 and 2.

[0053] As another approach to optimizing the apparatus of Figures 1 and 2 for use with a compressible gas, such as air, as the first fluid, the fluid separator(s) associated with the first stage may have a larger volume than the fluid separator(s) associated with the second stage, which may have a larger volume than the fluid separator(s) associated with the third stage, and similarly for the other stages.

[0054] When operating in the second operating mode ("air motor" mode), pressurized air (or other suitable gas) is supplied to the device inlet of device 1. As explained at the beginning of this detailed description, the device operates "in reverse", so that the device inlet in the second mode corresponds to the device outlet 47 in the first mode, and so on.

[0055] Those skilled in the art will appreciate that the present invention is not limited to the preferred embodiments described above, but rather many modifications and variations are possible within the scope of the appended claims.

[0056] In the claims, the word "comprising" does not exclude other elements or steps, and the indefinite article "a" or "an" does not exclude a plurality. A single processor or other unit may fulfill the functions of several items recited in the claims. The mere fact that certain measures are recited in mutually different dependent claims does not indicate that a combination of these measures cannot be used to advantage. Any reference signs in the claims should not be interpreted as limiting the scope.

Claims

1. A device (2) for converting rotation into fluid flow, This is the first stage, A first stage coiled fluid conduit (3) having an inlet (11) and an outlet (13) for receiving a first gaseous fluid having a first density and a second liquid fluid having a second density higher than the first density, wherein the first stage coiled fluid conduit (3) is arranged to transport batches of the first fluid and batches of the second fluid toward the outlet (13) of the first stage coiled fluid conduit (3) when the first stage coiled fluid conduit (3) rotates about a rotation axis (23), and is arranged to pressurize the first and second fluids to create a pressure difference between the outlet (13) and the inlet (11); The first stage first fluid separator (15) is configured to receive batches of the first fluid and batches of the second fluid output from the outlet (13) of the first stage coiled fluid conduit (3), and to separate the first fluid and the second fluid; The first section includes; This is the second stage, A second stage coiled fluid conduit (7) having an inlet (17) and an outlet (19) for receiving a first fluid and a second fluid, wherein the second stage coiled fluid conduit (7) is arranged to pressurize the first fluid and the second fluid such that a pressure difference is created between the outlet (19) and the inlet (17) when the second stage coiled fluid conduit (7) rotates about the rotation axis (23), thereby transporting batches of the first fluid and batches of the second fluid toward the outlet (19) of the coiled fluid conduit (7); The second stage first fluid separator is configured to receive batches of the first fluid and batches of the second fluid output from the outlet (19) of the second stage coiled fluid conduit (7), and to separate the first fluid and the second fluid; The second paragraph includes; The first interstage channel (21) is, To supply the first fluid to the inlet (17) of the second stage coiled fluid conduit (7), a first interstage flow path (21) connects the first fluid separator (15) of the first stage and the inlet (17) of the second stage coiled fluid conduit (7). Apparatus (2) comprising:

2. The apparatus (2) according to claim 1, wherein the first interstage flow path (21) is configured to supply the first fluid to the inlet (17) of the second stage coiled fluid conduit (7) without pressurizing the first fluid.

3. The apparatus (2) according to claim 1 or 2, wherein each of the first stage coiled fluid conduit (3) and the second stage coiled fluid conduit (7) is wound around the rotating shaft (23).

4. The third section, A coiled fluid conduit (9) having an inlet (35) and an outlet (37) for receiving a first fluid and a second fluid, wherein the coiled fluid conduit (9) is arranged to pressurize the first fluid and the second fluid and transport batches of the first fluid and batches of the second fluid toward the outlet (37) of the coiled fluid conduit (9) when the coiled fluid conduit (9) rotates about the rotation axis (23); A third stage first fluid separator (39) is configured to receive batches of the first fluid and batches of the second fluid from the outlet (37) of the second stage coiled fluid conduit (9) and separate the first fluid and the second fluid. The third paragraph includes; The second interstage flow path (43) connects the first fluid separator (16) of the second stage and the inlet (35) of the coiled fluid conduit (9) of the third stage in order to supply the first fluid to the inlet (35) of the coiled fluid conduit (9) of the third stage, Furthermore, Each of the first stage coiled fluid conduit (3), the second stage coiled fluid conduit (7), and the third stage coiled fluid conduit (9) is wound around the rotating shaft (23); The second interstage flow path (43) extends, at least partially, into the first coil formed by the first stage coil-shaped fluid conduit (3). The apparatus (2) according to claim 1 or 2.

5. The apparatus (2) according to claim 1 or 2, further comprising an internal stage channel (25) connecting the first fluid separator (15) of the first stage and the inlet (11) of the coiled fluid conduit (3) of the first stage, to enable the second fluid separated by the first fluid separator (15) of the first stage to be transported toward the inlet (11) of the coiled fluid conduit (3) of the first stage.

6. The apparatus (2) according to claim 5, wherein the internal flow path (25) of the first stage extends within the first coil formed by the coil-shaped fluid conduit (3) of the first stage.

7. Each of the first stage coiled fluid conduit (3) and the second stage coiled fluid conduit (7) is wound around the rotating shaft (23); The apparatus (2) according to claim 6, wherein the interstage flow path (21) of the first stage and the intrastage flow path (25) of the first stage are coaxial with respect to the rotation axis (23) along at least a portion of the total length of the intrastage flow path (25) of the first stage.

8. The apparatus (2) according to claim 1 or 2, further comprising an internal stage channel connecting the first fluid separator of the second stage and the inlet (17) of the coiled fluid conduit (7) of the second stage, in order to enable the second fluid separated by the first fluid separator of the second stage to be transported toward the inlet (17) of the coiled fluid conduit (7) of the second stage.

9. The apparatus (2) according to claim 1 or 2, wherein the second stage coiled fluid conduit (7) is located radially inward of the first coil formed by the first stage coiled fluid conduit (3).

10. Conversion mechanism (1), Apparatus (2) according to claim 1 or 2; A support structure (5) for holding the device (2) is held such that when the first stage coiled fluid conduit (3) is rotated about the rotation axis (23), the vertical level (h1) of the center (31) of the circle formed by the inlet (11) of the first stage coiled fluid conduit (3) is higher than the vertical level (h2) of the center (33) of the circle formed by the outlet (13) of the first stage coiled fluid conduit (3) when the first stage coiled fluid conduit (3) is rotated about the rotation axis (23), and the vertical offset distance (Δh) is selected such that the pressure exerted by the fluid column of the second fluid having a height equal to the vertical offset distance (Δh) substantially matches the pressure difference between the outlet (13) and the inlet (11) of the first stage coiled fluid conduit (3). Support structure (5) and A conversion mechanism (1) comprising:

11. The conversion mechanism (1) according to claim 10, wherein the support structure (5) holds the first stage coiled fluid conduit (3) such that the rotation axis (23) is inclined with respect to the horizontal plane by an angle within the range of 35° to 65°.

12. The device (2) comprises a plurality of stages within the range of 4 to 7 stages, Each stage of the aforementioned device (2) is: A coiled fluid conduit having an inlet and an outlet for receiving a first fluid and a second fluid, wherein the coiled fluid conduit is arranged to pressurize the first fluid and the second fluid as it rotates around a rotation axis, and to transport batches of the first fluid and batches of the second fluid toward the outlet of the coiled fluid conduit; A first fluid separator configured to receive batches of the first fluid and batches of the second fluid from the outlet of the coiled fluid conduit, and to separate the first fluid and the second fluid; A stepped channel, which connects the first fluid separator and the inlet of the coiled fluid conduit, and which allows the second fluid separated by the first fluid separator to be transported toward the inlet of the coiled fluid conduit by the pressure difference between the outlet and the inlet of the coiled fluid conduit; Includes, The interstage flow path connects the first fluid separator of each stage, which has a subsequent stage for compressing the first fluid to a higher pressure, to the inlet of the coiled fluid conduit of the subsequent stage for supplying the first fluid to the inlet of the coiled fluid conduit of the second stage; Each of the coiled fluid conduits in each stage is wound around the rotating shaft; The rotation axis is tilted at an angle within the range of 35° to 65° with respect to the horizontal plane. The conversion mechanism (1) according to claim 10.

13. A device (2) for converting a fluid flow into rotation around a rotation axis (23), An inlet for receiving a pressurized first fluid in gaseous form having a first density; A device outlet (29) for discharging the first fluid, which has been depressurized from the device (2); This is the first stage, A coiled fluid conduit (9) adapted for alternately transporting a batch of a first fluid and a batch of a liquid second fluid having a second density higher than the first density, from the inlet of the first coiled fluid conduit (9) which is in fluid communication with the inlet of the device, toward the outlet of the first coiled fluid conduit (9), while reducing the pressure of the first and second fluids and creating a pressure difference between the outlet and inlet of the first coiled fluid conduit (9); A first fluid separator of the first stage, configured to receive batches of the first fluid and batches of the second fluid output from the outlet of the coiled fluid conduit (9) of the first stage, and to separate the first fluid and the second fluid; The first section includes; This is the second stage, The second stage coiled fluid conduit (7) is adapted to alternately transport batches of the first fluid and batches of the second fluid from the inlet to the outlet of the second stage coiled fluid conduit (7), while reducing the pressure of the first fluid and the second fluid as the second stage coiled fluid conduit (7) rotates around the rotation axis (23), thereby providing a pressure difference between the outlet and the inlet of the second stage coiled fluid conduit (7); The second stage first fluid separator is configured to receive batches of the first fluid and batches of the second fluid output from the outlet of the second stage coiled fluid conduit (7), and to separate the first fluid and the second fluid; A first interstage flow path, which connects the first fluid separator of the first stage and the inlet of the coiled fluid conduit (7) of the second stage in order to supply the first fluid to the inlet of the coiled fluid conduit of the second stage, and The second section includes Apparatus (2) comprising:

14. The apparatus (2) according to claim 13, wherein the first interstage flow path is configured to supply the first fluid to the inlet (19) of the second stage coiled fluid conduit (7) without reducing the pressure of the first fluid.

15. Conversion mechanism (1), Apparatus (2) according to claim 13 or 14; A support structure (5) for holding the device (2), wherein when the first stage coiled fluid conduit (9) is rotated around the rotation axis (23), the vertical level of the center of the circle formed by the inlet of the first stage coiled fluid conduit (9) is lower than the vertical level of the center of the circle formed by the outlet of the first stage coiled fluid conduit (9) when the first stage coiled fluid conduit (9) is rotated around the rotation axis (23), and the vertical offset distance is selected such that the pressure exerted by a fluid column of a second fluid having a height equal to the vertical offset distance substantially matches the pressure difference between the outlet and the inlet of the first stage coiled fluid conduit (9), and A conversion mechanism (1) comprising:

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