Liquid ring pump for aircraft and associated operating method

Abstract

A liquid ring pump (1) configured for circulating a fluid in a fluid circuit and comprising: a cylindrical body (2) defining an internal volume (20) filled with a working fluid forming, in an operating configuration, a liquid ring around the periphery of the internal volume (20); and at least one impeller (3) mounted rotatably offset within 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), configured to close each cavity (32) of the impeller (3) upstream and downstream, respectively. (Shortcut Figure: Figure 3)

Description

Title of the invention: Liquid ring pump for aircraft and associated method of use. Technical field

[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 for supplying an aircraft turbomachine.

[0003] With reference to [Fig.1], 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 an operating liquid L, for example fuel. As is known, the cylindrical body 200 comprises 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 orifice 220 for the admission of a fluid F into the internal volume 210 and an outlet orifice 230, geometrically opposite the inlet orifice 220, for the discharge of the fluid F. The inlet orifice 220 and the outlet orifice 230 are precisely formed and calibrated to allow the admission and discharge of the fluid F.

[0004] The impeller 300 is rotatably mounted in the cylindrical body 200 and extends, along an axis of rotation R, off-center with respect to the cylindrical body 200, as shown in [Fig. 1]. The impeller 300 comprises a plurality of blades 310, each pair of two adjacent blades 310 defining, in an inter-blade space, a cavity 320 for receiving the fluid to be pumped F.

[0005] In practice, with reference to [Fig. 2], when the impeller 300 rotates in the cylindrical body 200, the operating fluid L is carried along by the effect of centrifugal force and forms, at 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 off-center within the cylindrical body 200, the useful volume VU varies according to the angular position of the cavity 320, as shown in [Fig. 2]. An increasing useful volume VU allows the fluid to be drawn in, via the inlet orifice 220, to be pumped into the cylindrical body 200. A Conversely, a decreasing useful volume VU allows the fluid to be pumped F to be compressed before its discharge through the outlet orifice 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 implementation of the pump and increases manufacturing time and costs. Furthermore, reduced operating clearances can lead to friction of the impeller 300 against the walls of the cylindrical body 200, which increases pump wear. Friction can also cause the impeller 300 and / or the cylindrical body 200 to overheat, which is undesirable, particularly when the fluid F is a flammable fluid, such as fuel.

[0009] To mitigate these drawbacks, liquid ring pumps are known, comprising an elongated cylindrical body in which a worm gear (which replaces the impeller) is mounted. The fluid to be pumped flows axially through the cylindrical body, and the liquid ring has the shape of 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 has a significant footprint 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 to be pumped.

[0011] The invention thus aims to eliminate at least some of these drawbacks by proposing a new liquid ring pump that ensures effective sealing while limiting its size, as well as manufacturing time and constraints. PRESENTATION OF THE INVENTION

[0012] The invention relates to a liquid ring pump configured to circulate a fluid in a fluid circuit, in particular an aircraft fluid circuit, the liquid ring pump comprising: • a cylindrical body extending from an upstream end to a downstream end along a principal axis and comprising an upstream end wall and a downstream end wall that are flat and orthogonal to the principal axis, connected by a circumferential wall, the cylindrical body being hollow and defining an internal volume, with an operating fluid partially filling the volume internally, the liquid ring pump has an upstream inlet port for admitting fluid into the internal volume and a downstream outlet port for discharging the fluid, • at least one paddle wheel mounted in the cylindrical body, the paddle wheel being mounted to rotate about an axis of rotation parallel to the main 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 which extends 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.

[0013] 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 upstream and downstream respectively so as to prevent the transfer of fluid between two adjacent cavities.

[0014] 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.

[0015] In a preferred embodiment, the upstream and downstream sealing walls are disc-shaped, which limits disturbances to the operating fluid when the pump is in its operating configuration. In other words, the formation of the liquid ring is not disturbed, and the pump can operate optimally and similarly to prior art liquid ring pumps.

[0016] According to a preferred aspect, the upstream inlet port is formed in the upstream end wall of the cylindrical body, which allows for the formation of 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.

[0017] 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 being 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. The inlet of the pumped fluid is thus less complex to implement, which simplifies the fluid circuit connected to the pump. Inlet via such an inlet passage also eliminates the need to create a calibrated opening, as was the case in the prior art, thereby reducing manufacturing costs and time.

[0018] 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.

[0019] 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. The liquid ring pump is thus less complex and less expensive to manufacture.

[0020] 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 size of the pump.

[0021] In a preferred embodiment, the paddle wheel comprises: • at least one separating wall extending orthogonally to the main axis and configured to separate the waterwheel into at least one adjacent upstream and downstream wheel, the upstream wheel comprising a plurality of upstream cavities, the downstream wheel 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.

[0022] The fluid can thus be admitted into a cavity of the upstream impeller which communicates with a cavity of the downstream impeller to be 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.

[0023] According to a preferred aspect, each downstream cavity is connected to an upstream cavity whose angular position is phase-shifted around the axis of rotation relative to said downstream cavity. This allows the pressurized fluid to be discharged through a downstream outlet orifice formed opposite the upstream inlet orifice, 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" means that the position of the downstream cavity is angularly offset around the axis of rotation relative to the position of the upstream cavity.

[0024] 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°.

[0025] 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.

[0026] Finally, the invention relates to a method of using the liquid ring pump as described above, the liquid ring pump being in an operating configuration, the operating liquid forming a liquid ring that extends radially around the periphery of the internal volume, the method of use comprising the steps of: • admit the fluid to be pumped via the inlet port, • fill one of the cavities of the paddle wheel, • Displace the fluid to be pumped through the outlet port. PRESENTATION OF THE FIGURES

[0027] 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.

[0028] Fig. 1 is a schematic representation of a liquid ring pump according to the prior art.

[0029] Fig. 2 is a schematic perspective representation of the liquid ring pump of Fig. 1 in an operating configuration.

[0030] Fig. 3 is a schematic representation of a liquid ring pump according to a first embodiment of the invention.

[0031] Fig. 4 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.

[0032] Fig. 5 is a front view of the pump of Fig. 4 in a usage configuration.

[0033] Fig. 6 is a schematic representation of the impeller of the liquid ring pump of Fig. 4.

[0034] Fig. 7 is a cross-sectional view of the paddle wheel of Fig. 6.

[0035] Fig. 8 is a perspective and partial cross-sectional view of the paddle wheel of the [Fig.6].

[0036] The [Fig.9] is a diagram of the steps of a method of using the pump of the [Fig.3] according to an embodiment of the invention.

[0037] The [Fig. 10] is a diagram of the steps of a method of using the pump of the [Fig.3] according to an alternative embodiment of the invention.

[0038] It should be noted that the figures set out the invention in detail to implement the invention, said figures being of course able to serve to better define the invention where appropriate. DETAILED DESCRIPTION OF THE INVENTION

[0039] 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.

[0040] It is shown in [Fig. 3], a liquid ring pump 1 in the form of realization of the invention. The liquid ring pump 1 comprises a cylindrical body 2 and an impeller 3 mounted in the cylindrical body 2.

[0041] The cylindrical body 2 extends from an upstream to a 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.

[0042] With reference to [Fig.3], 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 is understood that the cylindrical body 2 could alternatively have a different shape, for example an elliptical cylinder.

[0043] 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 [Fig. 5] by the filled volume indicated by the dashed line.

[0044] 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.

[0045] 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 is understood 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.

[0046] With reference to [Fig.3], 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.

[0047] 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.

[0048] Each pair of two adjacent blades 31 defines, in 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 liquid L. Each cavity 32 has its own effective volume VU (shown in [Fig. 5]) 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.

[0049] In this example, with reference to [Fig.5], 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.

[0050] To allow the circulation of fluid F in the liquid ring pump 1, with reference to [Fig. 3], 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).

[0051] 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.

[0052] Furthermore, in one embodiment, the downstream outlet orifice 22 is formed in the drive shaft of the impeller 3 to allow discharge of the pressurized fluid F, as will be described in more detail later.

[0053] 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.

[0054] 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 prior art liquid ring pumps 1.

[0055] 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.

[0056] 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 fixed 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.

[0057] 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.

[0058] 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.

[0059] In a preferred embodiment, the upstream sealing wall 4 has a circular shape, so as to limit any risk of disturbance of the fluid F in the pump, in the operating configuration. With reference to [Fig. 5], the upstream sealing wall 4 preferably has a diameter De 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 De of the upstream sealing wall 4.

[0060] In particular, with reference to Figures 4 and 5, the diameter De 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 [Fig. 4]. 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.

[0061] Similarly, in one embodiment, the downstream sealing wall 5 allows, in the operating configuration, a discharge passage 7 (shown in Figures 4) to be formed 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.

[0062] 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 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. The sealing walls 4, 5 correspond, in this embodiment, directly to the end faces of the cylinder formed by the paddle wheel 3.

[0063] 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 connected asymmetrically to the upstream faces 33 and downstream faces 34, or even have different shapes.

[0064] In one embodiment, with reference to [Fig. 6], the impeller 3 comprises 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, in this embodiment, the upstream impeller 3A 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.

[0065] With reference 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 fluidly 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°.

[0066] Such an 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 in 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 orifice 21 in one of the upstream cavities 32A, this cavity has a predetermined effective volume VU which fills. As the impeller 3 rotates in 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 useful volume VU of the upstream cavity 32A decreases, its pressure increases, unlike that of the downstream cavity. 32B, in which 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.

[0067] 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 transfers F between the upstream cavity 32A and the downstream cavity 32B which are fluidly connected when the latter are not opposite the upstream inlet orifice 21 and the downstream outlet orifice 22, thus increasing the efficiency of the pump.

[0068] A method for using the liquid ring pump will now be described. 1, according to an embodiment of the invention, with reference to [Fig.9]. 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 paddle wheel 3.

[0069] 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.

[0070] In this example, the liquid ring pump 1 is a pump mounted in a fuel circuit. In other words, the operating fluid L is a fuel. The fluid F to be pumped is also a fuel. As is known, during the priming of the pump, the fluid F to be pumped is initially air until fuel is drawn from a fuel supply line. When 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 comes into contact with the intake passage 7, thus limiting any risk pump priming. In other words, such a liquid ring pump 1 eliminates the need for a separate reservoir to supply the liquid ring W with operating fluid L, ensuring a constant volume of the latter, as was the case in prior art. This reduces the pump's size and mass.

[0071] In a 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.

[0072] In a second step 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.

[0073] In this example, in step E3, when the 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 located opposite the downstream outlet orifice 22 formed in this example in the drive shaft of the impeller 3. The compressed fluid F is discharged from the cylindrical body 2 via the downstream outlet orifice 22.

[0074] In the embodiment in which the impeller 3 includes a separating wall 8, with reference to [Fig. 10], 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.

[0075] 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° with respect to the angular position of the upstream cavity 32A.

[0076] As the impeller 3 rotates, the useful volume VU of the upstream cavity 32A decreases and the pressure increases. Simultaneously, the useful 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.

[0077] 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. Such an embodiment advantageously allows axial circulation of the fluid F along the principal axis X, through a simple inlet and outlet orifice. This simplifies the manufacture of the pump and limits its size as well as the size of the fluid circuit.

Claims

1. Demands 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 along a principal axis (X) and comprising an upstream end wall (24) and a downstream end wall (25) planar orthogonal to the principal axis (X) connected by a circumferential wall (23), the cylindrical body (2) being hollow and defining an internal volume (20), an operating liquid (L) partially filling the internal volume (20), the liquid ring pump (1) having an upstream inlet port (21) for the admission of the fluid (F) into the internal volume (20) and a downstream outlet port (22) for the discharge of the fluid (F), • at least one paddle wheel (3) mounted in the cylindrical body (2), the paddle wheel (3) being mounted to rotate about an axis of rotation (R) parallel to the main axis (X) and off-center with respect to the cylindrical body (2), the paddle wheel (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) which extends 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 paddle wheel (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 two adjacent cavities (32).

2. Liquid ring pump (1) according to claim 1, wherein the upstream sealing wall (4) and the downstream sealing wall (5) have the shape of a disc.

3. 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).

4. Liquid ring pump (1) according to any one of claims 1 to 3, wherein at least the upstream sealing wall (4) has a diameter (De) strictly less 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 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).

5. Liquid ring pump (1) according to any one of claims 1 to 4, 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).

6. Liquid ring pump (1) according to any one of claims 1 to 5, wherein the downstream outlet port (22) is formed in the downstream end wall (25) of the cylindrical body (2).

7. A liquid ring pump (1) according to any one of claims 1 to 6, 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 impeller downstream (3B) comprising a plurality of downstream cavities (32B), and • a plurality of circulation channels (9) for the fluid (F), each circulation channel (9) being formed between one of the upstream cavities (32A) and one of the downstream cavities (32B).

8. Liquid ring pump (1) according to claim 7, wherein each downstream cavity (32B) is connected to an upstream cavity (32A) whose angular position is out of phase around the axis of rotation (R).

9. Aircraft comprising a fluid circuit and a liquid ring pump (1) according to any one of claims 1 to 8 to permit the circulation of the fluid (F) in the fluid circuit.

10. A method of using the liquid ring pump (1) according to any one of claims 1 to 8, 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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