Liquid ring pump for aircraft and associated method of use

Abstract

The invention relates to a liquid ring pump (1) configured to circulate a fluid through a fluid circuit and comprising: a cylindrical body (2) having a liquid ring at the periphery of the inner volume (20); and at least one impeller (3) rotatably mounted eccentrically in the cylindrical body (2), the impeller (3) comprising a plurality of cavities (32), each being defined between two adjacent blades (31). The liquid ring pump (1) comprises an upstream sealing wall (4), fixedly connected to an upstream face (33) of the impeller (3), and a downstream sealing wall (5), fixedly connected to a downstream face (34) of the impeller (3), these walls being configured to close each cavity (32) of the impeller (3) respectively upstream and downstream. At least the upstream sealing wall (4) has a diameter (De) strictly smaller than a diameter (Dr) of the impeller (3), the diameter (De) of the upstream sealing wall (4) being determined so as to form, in the configuration of use, an intake duct (6) for the fluid (F) between an outer peripheral boundary (41) of the upstream sealing wall (4) and an inner peripheral boundary (Ll) of the liquid ring (W).

Description

Liquid ring pump for aircraft and associated operating method

[0001] The present invention relates to the field of vacuum pumps, and more particularly to the field of liquid ring pumps.

[0002] Liquid ring pumps are known to be used, for example, in a fuel circuit to supply an aircraft turbomachine.

[0003] With reference to the diagram, a liquid ring pump 100 comprises a cylindrical body 200 in which an impeller 300 is mounted. The cylindrical body 200, which extends along a principal axis X, is hollow and defines an internal volume 210 partially filled with a working fluid L, for example, fuel. As is known, the cylindrical body 200 has a wall of revolution and two end walls that form the bases of the cylinder and close the internal volume 210. As is known, the cylindrical body 200 includes an inlet port 220 for the admission of a fluid F into the internal volume 210 and an outlet port 230, geometrically opposite the inlet port 220, for the discharge of the fluid F. The inlet port 220 and the outlet port 230 are precisely formed and calibrated to allow the admission and discharge of the fluid F.

[0004] The impeller 300 is rotatably mounted within the cylindrical body 200 and extends, along an axis of rotation R, off-center with respect to the cylindrical body 200, as shown in the figure. The impeller 300 comprises a plurality of blades 310; each pair of two adjacent blades 310 defines, within an inter-blade space, a cavity 320 for receiving the fluid to be pumped F.

[0005] In practice, with reference to the diagram, when the impeller 300 rotates in the cylindrical body 200, the operating fluid L is carried along by centrifugal force and forms, around the periphery of the inner volume 210, a liquid ring W which at least partially covers the blades 310. As is known, in each cavity 320, a useful volume VU is defined and corresponds to the volume between the two adjacent blades 310 and the liquid ring W. The latter thus ensures the sealing of each of the useful volumes VU.

[0006] In practice, since the impeller 300 is offset within the cylindrical body 200, the effective volume VU varies according to the angular position of the cavity 320, as shown in the figure. An increasing effective volume VU allows the fluid to be drawn in, via the inlet port 220, and admitted into the cylindrical body 200. Conversely, a decreasing effective volume VU allows the fluid to be compressed before being discharged through the outlet port 230.

[0007] However, in such a liquid ring pump 100, the functional clearances between the impeller 300 and the end walls of the cylindrical body 200 can lead to sealing defects. In other words, fluid F can be transferred from one cavity 320 to another, which can impair the operation of the pump.

[0008] Therefore, the operating clearances must be limited, which implies a complex pump design and increases manufacturing time and costs. Furthermore, reduced operating clearances can lead to friction between the impeller 300 and the walls of the cylindrical body 200, increasing pump wear. Friction can also cause the impeller 300 and / or the cylindrical body 200 to overheat, which is undesirable, especially when the fluid F is flammable, such as fuel.

[0009] To mitigate these drawbacks, liquid ring pumps are known, comprising an elongated cylindrical body in which a worm gear (replacing the impeller) is mounted. The fluid to be pumped flows axially through the cylindrical body, and the liquid ring is shaped like a hollow cylinder. In such a pump, the effective volume is defined between two successive threads of the worm gear and the hollow liquid cylinder. Therefore, it is not necessary to ensure a seal between the impeller and the cylindrical body. However, due to the worm gear, such a pump is quite bulky and cannot be installed in an aircraft where space is limited.

[0010] To date, there is no compact and easy-to-implement liquid ring pump that has reliable sealing while ensuring optimal safety with regard to the fluid being pumped.

[0011] The invention thus aims to eliminate at least some of these disadvantages by proposing a new liquid ring pump which makes it possible to guarantee effective sealing while limiting its size as well as manufacturing times and constraints.

[0012] Incidentally, we know from document US20090290993A1 of a liquid ring compressor in which the impeller has side walls to increase the distance between the end of the blades and the casing and limit the variations in the tangential velocity of the liquid between a compression zone of the fluid to be pumped and an expansion zone. PRESENTATION OF THE INVENTION

[0013] The invention relates to a liquid ring pump configured for circulating a fluid in a fluid circuit, in particular an aircraft fluid circuit, the liquid ring pump comprising: a cylindrical body extending from upstream to downstream along a principal axis and comprising an upstream end wall and a downstream end wall planar and orthogonal to the principal axis connected by a circumferential wall, the cylindrical body being hollow and defining an internal volume, an operating fluid partially filling the internal volume, the liquid ring pump having an upstream inlet port for admitting the fluid into the internal volume and a downstream outlet port for discharging the fluid, at least one impeller mounted in the cylindrical body, the impeller being mounted to rotate about an axis of rotation parallel to the principal axis and offset from the cylindrical body.each pair of two adjacent blades defining an inter-blade space, the operating fluid forming, in an operating configuration, a liquid ring extending radially around the periphery of the internal volume of the cylindrical body, each blade being, in the operating configuration, at least partially immersed in the operating fluid and a cavity being defined in each inter-blade space between two adjacent blades and the liquid ring.

[0014] The liquid ring pump is remarkable in that it comprises: an upstream sealing wall mounted in the cylindrical body and fixedly connected to an upstream face of the impeller, and a downstream sealing wall mounted in the cylindrical body and fixedly connected to a downstream face of the impeller, the upstream sealing wall and the downstream sealing wall being configured to close each cavity of the impeller respectively upstream and downstream so as to prevent the transfer of fluid between two adjacent cavities.

[0015] Thanks to the sealing walls, the risk of leakage into the internal volume is eliminated. The liquid ring pump according to the invention thus eliminates the need for tight mounting clearances between the impeller and the end walls of the cylindrical body, resulting in both simpler and less expensive pump manufacturing and faster assembly. The risk of friction between the impeller and the cylindrical body is also advantageously reduced, which limits wear on the parts and ensures the pump's longevity. Furthermore, the risk of overheating is also reduced, which is particularly beneficial when the pump is installed, for example, in an aircraft fuel system. The liquid ring pump according to the invention ensures a high level of safety.

[0016] In a preferred embodiment, the upstream and downstream sealing walls are disc-shaped, which minimizes disturbances to the operating fluid when the pump is in its operating configuration. In other words, the formation of the liquid ring is not disrupted, and the pump can operate optimally, similarly to prior art liquid ring pumps.

[0017] According to a preferred design, the upstream inlet port is formed in the upstream end wall of the cylindrical body, resulting in an inlet port with a simple geometry, unlike the inlet ports of the prior art. The liquid ring pump is thus less complex to manufacture and therefore less expensive.

[0018] Preferably, at least the upstream sealing wall has a diameter strictly smaller than the diameter of the impeller. The diameter of the upstream sealing wall is determined so as to form, in the operating configuration, an inlet passage for the fluid between an outer peripheral limit of the upstream sealing wall and an inner peripheral limit of the liquid ring. Intake of the pumped fluid is thus less complex to implement, simplifying the fluid circuit connected to the pump. Intake via such an inlet passage also eliminates the need for a calibrated opening, as was the case in the prior art, thereby reducing manufacturing costs and time.

[0019] According to one aspect, the upstream sealing wall and the downstream sealing wall are mounted symmetrically on the upstream and downstream faces of the impeller, allowing, when the impeller is driven in rotation, the formation of a regular liquid ring, ensuring optimal operation of the pump.

[0020] Preferably, the downstream outlet port is formed in the downstream end wall of the cylindrical body, resulting in an outlet port with a simple geometry. This makes the liquid ring pump less complex and less expensive to manufacture.

[0021] In one embodiment, the upstream inlet port and the downstream outlet port are formed opposite each other respectively in the upstream end wall and in the downstream end wall, allowing axial circulation of the fluid in the pump, which simplifies the fluid circuit, while limiting the pump's footprint.

[0022] In a preferred embodiment, the impeller comprises: at least one separating wall extending orthogonally to the main axis and configured to separate the impeller into at least one adjacent upstream impeller and downstream impeller, the upstream impeller comprising a plurality of upstream cavities, the downstream impeller comprising a plurality of downstream cavities, and a plurality of fluid circulation channels, each circulation channel being formed between one of the upstream cavities and one of the downstream cavities.

[0023] The fluid can thus be admitted into a cavity of the upstream wheel, which communicates with a cavity of the downstream wheel, before being discharged. The fluid connection via the circulation channels between the upstream and downstream cavities allows, through a transfer mechanism between the cavities and a piston action, the fluid to be pressurized before being discharged.

[0024] According to a preferred design, each downstream cavity is connected to an upstream cavity whose angular position is phase-shifted around the axis of rotation relative to the downstream cavity. This allows the pressurized fluid to be discharged through a downstream outlet port formed opposite the upstream inlet port, thus enabling axial fluid circulation and reducing the overall size of the pump and the fluid circuit on which the pump is mounted. The term "phase-shifted" refers to the fact that the position of the downstream cavity is angularly offset around the axis of rotation relative to the position of the upstream cavity.

[0025] In one embodiment, each downstream cavity is connected to an upstream cavity whose angular position is out of phase around the axis of rotation, preferably by 120°.

[0026] The invention also relates to an aircraft comprising a fluid circuit and a liquid ring pump as described above, to allow the circulation of the fluid in the fluid circuit.

[0027] Finally, the invention relates to a method of using the liquid ring pump as described above, the liquid ring pump being in a configuration of use, the operating liquid forming a liquid ring which extends radially around the periphery of the internal volume, the method of use comprising the steps of: admitting the fluid to be pumped via the inlet port, filling one of the cavities of the impeller, discharging the fluid to be pumped via the outlet port. PRESENTATION OF THE FIGURES

[0028] The invention will be better understood upon reading the following description, given by way of example, and referring to the following figures, given by way of non-limiting examples, in which identical references are given to similar objects.

[0029] This is a schematic representation of a liquid ring pump according to the prior art.

[0030] This is a schematic perspective representation of the liquid ring pump in a usage configuration.

[0031] This is a schematic representation of a liquid ring pump according to a first embodiment of the invention.

[0032] Laest is a schematic representation of a liquid ring pump according to a second embodiment of the invention and showing the inlet and outlet of a fluid to be pumped.

[0033] This is a front view of the pump in a usage configuration.

[0034] This is a schematic representation of the impeller of the liquid ring pump.

[0035] This is a cross-sectional view of the waterwheel.

[0036] This is a perspective and partial cross-section view of the waterwheel.

[0037] This is a diagram of the steps of a process for using the pump according to an implementation method of the invention.

[0038] This is a diagram of the steps of a method for using the pump according to an alternative implementation of the invention.

[0039] It should be noted that the figures explain the invention in detail for implementing the invention, said figures being of course able to serve to better define the invention where appropriate. DETAILED DESCRIPTION OF THE INVENTION

[0040] The invention relates to a liquid ring pump, used for circulating a fluid in a fluid circuit, in particular a fluid circuit of an aircraft, for example a fuel circuit.

[0041] Figure 1 shows a liquid ring pump according to one embodiment of the invention. The liquid ring pump 1 comprises a cylindrical body 2 and an impeller 3 mounted in the cylindrical body 2.

[0042] The cylindrical body 2 extends from upstream to downstream along a principal axis X. In this document, the terms upstream and downstream refer to the direction of flow of a fluid F in the liquid ring pump 1 from upstream to downstream.

[0043] With reference to the, the cylindrical body 2 has, in this example, the shape of a right circular cylinder and, as such, comprises an upstream end wall 24 and a downstream end wall 25 connected by a circumferential wall 23. The upstream end wall 24 and the downstream end wall 25 are planar and extend orthogonally to the principal axis X. It goes without saying that the cylindrical body 2 could alternatively have a different shape, for example an elliptical cylinder.

[0044] The cylindrical body 2 is hollow and defines an internal volume 20 between the circumferential wall 23 and the upstream end walls 24 and downstream end walls 25. The internal volume 20 is partially filled with an operating fluid L, in this example, fuel. It is understood that the operating fluid L could be different. In an operating configuration, i.e., when the pump is running, the operating fluid L forms a liquid ring W that extends radially around the periphery of the internal volume 20 of the cylindrical body 2, as shown in the diagram by the filled volume indicated by the dashed line.

[0045] As described previously, a paddle wheel 3 is mounted in the cylindrical body 2. The paddle wheel 3 is rotatably mounted in the cylindrical body 2 and extends along an axis of rotation R parallel to the main axis X. In particular, the paddle wheel 3 extends off-center with respect to the cylindrical body 2, as shown in Figures 3 to 5.

[0046] To be driven in rotation, the paddle wheel 3 is mounted on a drive shaft (not shown), which is itself connected to a drive device to be driven in rotation about the axis of rotation R. In this example, the drive shaft is connected to an electric motor (also not shown). It goes without saying that the paddle wheel 3 could be driven in rotation in a different way, for example by means of a mechanical device, such as a gear.

[0047] With reference to the, the paddle wheel 3 comprises an upstream face 33 mounted opposite the upstream end wall 24 of the cylindrical body 2, and a downstream face 34 mounted opposite the downstream end wall 25 of the cylindrical body 2.

[0048] The paddle wheel 3 comprises a plurality of blades 31 which extend radially from the axis of rotation R and between the upstream face 33 and the downstream face 34, over the entire circumference of the paddle wheel 3. In this example, the upstream and downstream faces 33, 34 correspond directly to the upstream and downstream edges of the blades 31.

[0049] Each pair of two adjacent blades 31 defines, within an inter-blade space, a cavity 32 for receiving the fluid F. In practice, in the operating configuration described above, each blade 31 is at least partially immersed in the operating fluid L. Each cavity 32 has its own effective volume VU (shown in the figure) defined between the blades 31 and the liquid ring W. The effective volume VU of each cavity 32 is predefined according to its angular position in the cylindrical body 2 and is different from the effective volume VU of the adjacent cavities 32. As is known, when the effective volume VU decreases, the fluid F is compressed, and when the volume increases, the fluid F is expanded.

[0050] In this example, with reference to the, the impeller 3 has a diameter Dr which depends on the sizing of the liquid ring pump 1 and the volume of the cylindrical body 2 and the flow rate of fluid F to be pumped.

[0051] To allow the circulation of fluid F in the liquid ring pump 1, the latter includes an upstream inlet port 21 for the admission of fluid F into the internal volume 20 and a downstream outlet port 22 for the discharge of fluid F. The upstream inlet port 21 and the downstream outlet port 22 are through-holes to allow the circulation of fluid F. Also, the upstream inlet port 21 and the downstream outlet port 22 are preferably connected respectively to a supply pipe and a discharge pipe (not shown).

[0052] In a preferred embodiment, the upstream inlet orifice 21 is formed in the upstream end wall 24 of the cylindrical body 2. It is understood that the upstream inlet orifice 21 could be formed differently, for example in the circumferential wall 23 or at the level of the drive shaft of the paddle wheel 3.

[0053] Furthermore, in one embodiment, the downstream outlet orifice 22 is formed in the impeller drive shaft 3 to permit discharge of the pressurized fluid F, as will be described in more detail later.

[0054] In an alternative embodiment, as shown in Figures 3 and 4, the downstream outlet orifice 22 is formed in the downstream end wall 25. More specifically, the downstream outlet orifice 22 is formed, in this embodiment, preferably in the downstream end wall 25 opposite the upstream inlet orifice 21 along the main axis X, to allow axial circulation of the fluid F, which helps to limit the bulk of the fluid circuit.

[0055] When formed in the end walls 24, 25 of the cylindrical body 2, the upstream inlet orifice 21 and the downstream outlet orifice 22 preferably have a circular shape, allowing simple manufacturing of the liquid ring pump 1. The diameter of the upstream inlet orifice 21 and the downstream outlet orifice 22 are then calibrated to allow a predetermined flow rate of the fluid F in the liquid ring pump 1. It goes without saying that the upstream inlet orifice 21 and the downstream outlet orifice 22 can alternatively have a different shape, for example whose opening area decreases according to the direction of rotation of the impeller 3, as is the case in the liquid ring pumps 1 of the prior art.

[0056] According to one aspect of the invention, the liquid ring pump 1 comprises an upstream sealing wall 4 and a downstream sealing wall 5 fixedly connected to the impeller 3. The upstream sealing wall 4 and the downstream sealing wall 5 are mounted in the cylindrical body 2.

[0057] More specifically, preferably, with reference to Figures 3 and 4, the upstream sealing wall 4 is fixedly connected to the upstream face 33 of the impeller 3. The downstream sealing wall 5 is fixedly connected to the downstream face 34 of the impeller 3. In particular, in this example, the upstream sealing wall 4 and the downstream sealing wall 5 are made of the same material as the impeller 3. Preferably, the impeller 3 forms a single unit. It is understood that the sealing walls 4 and 5 could be attached in a different way, for example by welding, bonding, etc. The upstream sealing wall 4 and the downstream sealing wall 5 allow each cavity 32 of the impeller 3 to be closed upstream and downstream respectively, so as to prevent the transfer of fluid F between two adjacent cavities 32.The sealing walls 4, 5 thus advantageously allow for the elimination of reduced functional clearances during the manufacture of the liquid ring pump 1.

[0058] In a preferred embodiment, the upstream sealing wall 4 and the downstream sealing wall 5 are mounted symmetrically on the upstream face 33 and on the downstream face 34 of the paddle wheel 3. It is understood that the upstream sealing wall 4 and the downstream sealing wall 5 could alternatively be mounted differently on the upstream face 33 and on the downstream face 34 of the paddle wheel 3.

[0059] Preferably, the upstream sealing wall 4 and the downstream sealing wall 5 are identical. Therefore, only the upstream sealing wall 4 will be described hereafter. Similar characteristics apply, in this example, to the downstream sealing wall 5.

[0060] In a preferred embodiment, the upstream sealing wall 4 has a circular shape to minimize any risk of disturbance to the fluid F in the pump during operation. With reference to the diagram, the upstream sealing wall 4 preferably has a diameter Dc strictly smaller than the diameter Dr of the impeller 3, so as to allow the fluid F to be admitted directly into the cavities 32 when the upstream inlet orifice 21 is formed in the upstream end wall 24. The thickness of the liquid ring W is thus preferably greater than the difference Dr-Dc between the diameter Dr of the impeller 3 and the diameter Dc of the upstream sealing wall 4.

[0061] In particular, with reference to Figures 4 and 5, the diameter Dc of the upstream sealing wall 4 is preferably determined so as to form, in the operating configuration, an inlet passage 6 for the fluid F between an outer peripheral limit 41 of the upstream sealing wall 4 and an inner peripheral limit L1 of the liquid ring W. The inlet passage 6 thus has a crescent shape that allows the fluid F to be progressively admitted into the internal volume 20. In this example, the upstream inlet orifice 21 is formed in the upstream end wall 24 of the cylindrical body 2, opposite the inlet passage 6, as shown in Figure 5. This allows the fluid F from the upstream inlet orifice 21 to be admitted directly into the cavity 32 positioned opposite it, via the inlet passage 6, as will be described in more detail later.

[0062] Similarly, in one embodiment, the downstream sealing wall 5 allows, in the operating configuration, a discharge passage 7 (represented in Figures 4) for the fluid F between the outer peripheral limit 41 of the downstream sealing wall 5 and the inner peripheral limit L1 of the liquid ring W. Preferably, the downstream outlet orifice 22 is formed, in the downstream end wall 25 of the cylindrical body 2, opposite the discharge passage 7.

[0063] This document describes a paddle wheel 3 in which the upstream sealing wall 4 and the downstream sealing wall 5 are connected, respectively, to the upstream face 33 and the downstream face 34 of the paddle wheel 3, corresponding directly to the edges of the blades 31. However, it is understood that the paddle wheel 3 could alternatively have the shape of a cylinder comprising two end faces and in which the cavities 32 would be formed, for example by machining. In this embodiment, the sealing walls 4 and 5 correspond directly to the end faces of the cylinder formed by the paddle wheel 3.

[0064] Similarly, this document describes an identical upstream sealing wall 4 and downstream sealing wall 5; however, it is understood that the sealing walls 4 and 5 could alternatively be different. For example, the sealing walls 4 and 5 could be asymmetrically connected to the upstream faces 33 and downstream faces 34, or even have different shapes.

[0065] In one embodiment, the impeller 3 includes a separating wall 8 extending orthogonally to the axis of rotation R and dividing each cavity 32 into two adjacent cavities 32. In other words, the impeller 3 can be considered as divided into an adjacent upstream impeller 3A and a downstream impeller 3B. More precisely, the upstream impeller 3A, in this embodiment, comprises a plurality of upstream cavities 32A, and the downstream impeller 3B, a plurality of downstream cavities 32B. The upstream cavities 32A are aligned with the downstream cavities 32B along the axis of rotation R.

[0066] Referring to Figures 7 and 8, each upstream cavity 32A is fluidically connected, via a circulation channel 9, to one of the downstream cavities 32B. In particular, each upstream cavity 32A is fluidically connected to a downstream cavity 32B whose angular position, along the axis of rotation R, is different from the angular position of the upstream cavity 32A. In this example, each upstream cavity 32A is connected to a downstream cavity 32B whose angular position is phase-shifted by three cavities around the axis of rotation R, i.e., by 120°.

[0067] This embodiment allows the fluid F to be transferred from an upstream cavity 32A to a downstream cavity 32B through the circulation channel 9, by the pressure difference between the upstream cavity 32A and the downstream cavity 32B, which have different effective volumes (VU) and therefore different pressures. Indeed, due to the impeller 3 being off-center within the cylindrical body 2 and the phase shift between the upstream cavities 32A and the downstream cavities 32B, when the fluid F arrives from the upstream inlet 21 into one of the upstream cavities 32A, that cavity has a predetermined effective volume (VU) which fills. As the impeller 3 rotates within the cylindrical body 2, the effective volume (VU) of the upstream cavity 32A opposite the inlet passage 6 decreases. Simultaneously, the useful volume VU of the downstream cavity 32B to which the upstream cavity 32A is connected increases and the downstream cavity 32B fills with the fluid F contained in the upstream cavity 32A by aspiration.Indeed, as the usable volume (VU) of the upstream cavity 32A decreases, its pressure increases, unlike the downstream cavity 32B, where the pressure decreases as its volume increases. In other words, the upstream cavities 32A and the downstream cavities 32B are connected by a system of communicating vessels or a piston effect.

[0068] In an alternative embodiment not shown, the impeller 3 comprises two separating walls 8 extending successively orthogonally to the axis of rotation R, so as to form three adjacent impellers 3, for example, an upstream impeller 3A, a downstream impeller 3B, and an intermediate impeller. Each cavity 32 of the intermediate impeller is in fluidic contact, via a first circulation channel 9, with an upstream cavity 32A and, via a second circulation channel 9, with a downstream cavity 32B. Preferably, each cavity 32 of the intermediate impeller is out of phase in one direction with the upstream cavity 3A to which it is connected and, in the opposite direction, with the downstream cavity 3B to which it is connected.A paddle wheel 3 comprising three successive wheels prevents fluid F transfers between the upstream cavity 32A and the downstream cavity 32B which are fluidly connected when the latter are not in view of the upstream inlet orifice 21 and the downstream outlet orifice 22, which increases the efficiency of the pump.

[0069] A method for using the liquid ring pump 1, according to an embodiment of the invention, will now be described with reference to the figure. In this example, the upstream inlet orifice 21 is formed in the upstream end wall 24 of the cylindrical body 2 and the downstream outlet orifice 22 is formed in the drive shaft of the impeller 3.

[0070] The liquid ring pump 1 is activated, for example, by driving an electric motor to drive the impeller shaft 3. The impeller 3 is then placed in its operating configuration, and the operating fluid L is driven, under the effect of centrifugal force, against the circumferential wall 23 of the cylindrical body 2, forming a liquid ring W that extends radially around the periphery of the inner volume 20. An inlet passage 6 is formed between the outer peripheral limit 41 of the upstream sealing wall 4 and the inner peripheral limit L1 of the liquid ring W. The upstream inlet orifice 21 is formed, in this example, opposite the inlet passage 6. In this example, the downstream outlet orifice 22 is formed in the drive shaft of the impeller 3.

[0071] In this example, the liquid ring pump 1 is a pump mounted in a fuel circuit. That is, the operating fluid L is a fuel. The fluid F to be pumped is also a fuel. As is known, during pump priming, the fluid F to be pumped is initially air until fuel is drawn from a fuel supply line. Once priming is complete and there is no more air to be drawn in, the fluid F increases the volume of the liquid ring W, which then aligns with the inlet passage 7, thus limiting any risk of the pump losing its prime. In other words, such a liquid ring pump 1 eliminates the need for a separate reservoir to supply the liquid ring W with the operating fluid L, ensuring that the latter has a constant volume, as was the case in the prior art. This reduces the size and mass of the pump.

[0072] In the first step E1, the fluid F is admitted into the cavity 32 opposite the inlet passage 6, and the impeller 3 rotates around the axis of rotation R, in this example, in a clockwise direction. The cavity 32 fills until it is no longer opposite the inlet passage 6.

[0073] In a second stage E2, as the paddle wheel 3 rotates, due to its off-center position in the cylindrical body 2, the useful volume VU of the cavity 32 which has admitted fluid F decreases and the fluid F contained in the cavity 32 is compressed.

[0074] In this example, during step E3, when cavity 32 is positioned angularly at approximately 180° relative to the angular position of the inlet passage 6, the fluid F is compressed to its maximum. The filled cavity 32 is then aligned with the downstream outlet 22 formed in this example in the impeller drive shaft 3. The compressed fluid F is discharged from the cylindrical body 2 via the downstream outlet 22.

[0075] In the embodiment in which the impeller 3 includes a separating wall 8, with reference to the, a discharge passage 7 is formed opposite the inlet passage 6 between the outer peripheral limit 51 of the downstream sealing wall 5 and the inner peripheral limit L1 of the liquid ring W. The downstream outlet orifice 22 is then formed in the downstream end wall 5 opposite the upstream inlet orifice 21 formed in the upstream end wall 4.

[0076] In this embodiment, the fluid F is admitted, in a step EA, into one of the upstream cavities 32A positioned opposite the inlet passage 6, via the upstream inlet orifice 21. The upstream cavity 32A is fluidically connected to a downstream cavity 32B whose angular position is offset, in this example, by 120° relative to the angular position of the upstream cavity 32A.

[0077] As the impeller 3 rotates, the usable volume VU of the upstream cavity 32A decreases and the pressure increases. Simultaneously, the usable volume VU of the associated downstream cavity 32B increases. The fluid F is then transferred from the upstream cavity 32A to the downstream cavity 32B, and the downstream cavity 32B fills due to a piston effect between the two cavities 32.

[0078] When the downstream cavity 32B reaches an angular position opposite the discharge passage 7, the fluid F is discharged via the downstream outlet orifice 22, in a step EB. This method of implementation advantageously allows axial circulation of the fluid F along the main axis X, through a single inlet and outlet orifice, which simplifies the manufacture of the pump and reduces its size as well as the size of the fluid circuit.

Claims

Liquid ring pump (1) configured to circulate a fluid (F) in a fluid circuit, in particular an aircraft fluid circuit, the liquid ring pump (1) comprising: a cylindrical body (2) extending from an upstream to a downstream end along a principal axis (X) and comprising an upstream end wall (24) and a downstream end wall (25) planar perpendicular to the principal axis (X) connected by a circumferential wall (23), the cylindrical body (2) being hollow and defining an internal volume (20), a working fluid (L) partially filling the internal volume (20), the liquid ring pump (1) having an upstream inlet port (21) for admitting the fluid (F) into the internal volume (20) and a downstream outlet port (22) for discharging the fluid (F), at least one impeller (3) mounted in the cylindrical body (2),The impeller (3) being mounted for rotation about an axis of rotation (R) parallel to the main axis (X) and offset from the cylindrical body (2), the impeller (3) comprising a plurality of blades (31), each pair of two adjacent blades (31) defining an inter-blade space, the operating fluid (L) forming, in an operating configuration, a liquid ring (W) extending radially around the periphery of the internal volume (20) of the cylindrical body (2), each blade (31) being, in the operating configuration, at least partially immersed in the operating fluid (L), and a cavity (32) being defined in each inter-blade space between two adjacent blades (31) and the liquid ring (W), the liquid ring pump (1) being characterized in that it comprises: an upstream sealing wall (4) mounted in the cylindrical body (2) and fixedly connected to an upstream face (33) of the impeller (3),and a downstream sealing wall (5) mounted in the cylindrical body (2) and fixedly connected to a downstream face (34) of the impeller (3), the upstream sealing wall (4) and the downstream sealing wall (5) being configured to close each cavity (32) of the impeller (3) respectively upstream and downstream so as to prevent the transfer of fluid (F) between at least two adjacent cavities (32), the upstream sealing wall (4) having a diameter (Dc) strictly less than a diameter (Dr) of the impeller (3), the diameter (Dc) of the upstream sealing wall (4) being determined so as to form, in the operating configuration, an inlet passage (6) for the fluid (F) between an outer peripheral limit (41) of the upstream sealing wall (4) and an inner peripheral limit (L1) of the liquid ring (W). Liquid ring pump (1) according to claim 1, in which the upstream sealing wall (4) and the downstream sealing wall (5) have the shape of a disc. Liquid ring pump (1) according to claim 2, wherein the upstream inlet orifice (21) is formed in the upstream end wall (24) of the cylindrical body (2). Liquid ring pump (1) according to any one of claims 1 to 3, wherein the upstream sealing wall (4) and the downstream sealing wall (5) are mounted symmetrically on the upstream face (33) and the downstream face (34) of the impeller (3). Liquid ring pump (1) according to any one of claims 1 to 4, wherein the downstream outlet port (22) is formed in the downstream end wall (25) of the cylindrical body (2). Liquid ring pump (1) according to any one of claims 1 to 5, wherein the impeller (3) comprises: at least one separating wall (8) extending orthogonally to the main axis (X) and configured to separate the impeller (3) into at least one adjacent upstream impeller (3A) and downstream impeller (3B), the upstream impeller (3A) comprising a plurality of upstream cavities (32A), the downstream impeller (3B) comprising a plurality of downstream cavities (32B), and a plurality of fluid circulation channels (9) (F), each circulation channel (9) being formed between one of the upstream cavities (32A) and one of the downstream cavities (32B). Liquid ring pump (1) according to claim 6, in which each downstream cavity (32B) is connected to an upstream cavity (32A) whose angular position is out of phase around the axis of rotation (R). Aircraft comprising a fluid circuit and a liquid ring pump (1) according to any one of claims 1 to 7 to allow circulation of the fluid (F) in the fluid circuit. Method of using the liquid ring pump (1) according to any one of claims 1 to 7, the liquid ring pump (1) being in a configuration of use, the working liquid (L) forming a liquid ring (W) which extends radially around the periphery of the internal volume (20), the method of use comprising the steps of: admitting the fluid to be pumped via the inlet port (21), filling one of the cavities (32) of the impeller (3), discharging the fluid to be pumped via the outlet port (22).

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