Reservoir with oil level probe

Abstract

The invention proposes an oil reservoir for a turbine engine, the oil reservoir being provided with a probe (48) for measuring the oil level. The probe may be a capacitive electrical probe that is inserted into the oil reservoir so as to be arcuate. A sleeve (66) surrounds the layered electrodes (60, 62) of the probe (48) to direct the probe (48) into the oil reservoir during installation and hold the electrodes in place. A method of installing a probe (48) in a reservoir (30) is also disclosed.

Description

Technical Field

[0001] The present invention relates to measuring the level of a liquid, particularly oil, in a tank of a turbine. The present invention also relates to a turbine, particularly a turbojet engine or a turboprop engine of an aircraft. The present invention also relates to a method for installing a measurement probe in a tank. Background Art

[0002] In a turbine, a liquid tank, particularly an oil tank, generally has an arcuate shape that surrounds a curved part of the turbine, particularly to limit the size of the turbine.

[0003] Measuring the oil level in a tank can involve different techniques, including capacitive or resistive probes that measure the change in capacitance or resistance in the tank and infer the amount of oil.

[0004] Although a slightly curved tank can accommodate a straight measurement probe, this is not the case for a tank with a small radius of curvature: a straight probe inserted into a highly curved tank will contact the inner wall of the tank. This can establish an electrical contact that can disrupt the measurement. In addition, a straight probe cannot be inserted deep enough to reach the bottom of the tank, so when the liquid level is particularly low, the straight probe cannot transmit a value.

[0005] Thus, it is known in particular from document EP 3 399 164 B1 to provide an arcuate probe according to the overall curvature of the tank. This probe is housed in a sheath or a plurality of supports, and thus the arcuate shape of the probe is imposed on it. This design has some limitations, particularly in terms of protecting the probe during insertion into the tank, because the sheath or the supports can affect the space between the electrodes or even damage the electrodes. In addition, this design is not suitable for a one-piece tank produced by additive manufacturing, because the supports or the sheath, which are components in contact with the probe, cannot be made of metal. Summary of the Invention

[0006] Technical Problem

[0007] The present invention aims to solve at least one of the problems caused by the prior art. More specifically, the present invention aims to propose a lightweight design in which the assembly and disassembly of the oil level measurement probe are facilitated, and in which the measurement accuracy is ensured not to deteriorate even for a significant tank curvature.

[0008] Technical Solution

[0009] The present invention relates to an oil tank for a turbine, the oil tank comprising: a generally curved wall; an electrical oil level measurement probe having one or more arcuate laminated electrodes following the curvature of the wall; and at least one sleeve, characterized in that the sleeve is mounted on the laminated electrode to be inserted between the electrode and the wall, and the sleeve is fixed to the probe and simultaneously fixed to the wall.

[0010] Thus, the sleeve prevents the electrodes from coming into direct contact with the tank, which is advantageous for avoiding any damage to the electrodes, preventing contact between the electrodes and metal components, and ensuring the correct positioning of the electrodes.

[0011] According to an advantageous embodiment of the invention, the sleeve has a rectangular shape and is transverse to the longitudinal axis of the layered electrode. This arrangement enables good compactness, and the fact that the sleeve is perpendicular to the longitudinal direction of the electrode prevents the electrode from being distorted.

[0012] According to an advantageous embodiment of the invention, the sleeve includes an internal notch for receiving the layered electrode. Thus, the layered electrode can be precisely positioned in the tank. This ensures measurement accuracy: in fact, if the electrode moves in the tank during flight, the position of the electrode no longer corresponds to its initial position (during or at the time of calibration).

[0013] According to an advantageous embodiment of the invention, the notch is formed by a protruding "V"-shaped projection. This shape makes it easier to place the thin layer in the sleeve because the thin layer is clamped in the notch, and thus it is easier to fix the thin layer to the sleeve. The elasticity of the projection also helps to correctly hold the electrode in place.

[0014] According to an advantageous embodiment of the invention, the sleeve includes a through lumen that is completely occupied by the layered electrode and the wedge. This not only enables the thin layer to be well held in place but also prevents oil from penetrating and being trapped in the sleeve.

[0015] According to an advantageous embodiment of the invention, the sleeve has a generally rectangular shape with its two opposite ends located in spherical portions. This shape facilitates the entry of the probe together with the sleeve into the tank and prevents the sleeve from damaging the tank wall. In addition, the absence of sharp edges on the sleeve prevents scratching of the tank wall and the generation of particles that could spread into the oil.

[0016] According to an advantageous embodiment of the invention, the sleeve is fixed to the probe by a pin, rivet, or screw element that engages in a hole in exactly one of the electrodes. When there are multiple electrodes, it is sufficient to fix to a single electrode, avoiding overconstraining the electrodes. Alternatively, multiple fixing means can be provided to fix each electrode to the sleeve.

[0017] According to an advantageous embodiment of the invention, the tank includes a plurality of sleeves, and the wall has a non-constant curvature. The sleeves are irregularly distributed along the probe, and as the curvature of the wall increases, the sleeves are spaced farther apart from each other. This avoids areas where bending stress accumulates and thus gradually smooths the bending stress on the probe. Therefore, damage to the probe is avoided, and measurement accuracy is ensured. Alternatively, the curvature is constant, and the sleeves are regularly spaced along the probe. The sleeves can be distributed over most or substantially the entire length of the probe.

[0018] According to an advantageous embodiment of the invention, the wall is the wall of an arcuate sheath, the arcuate sheath preferably being formed by two facing U-shaped profiles connected by a mesh. Thus, the sleeve can contact the U-shaped part with a slight assembly clearance. The mesh enables the oil to flow, thus preventing the oil from accumulating in the sleeve or the sheath. Alternatively or additionally, the sheath can be the sheath described in document EP 3399 164 B1, i.e., a hinged sheath. The sheath can extend over most or substantially the entire length of the probe. The sheath can extend over most or substantially the entire length of the tank. Alternatively, the wall in contact with the sleeve is the inner wall of the tank.

[0019] According to an advantageous embodiment of the invention, the sleeve is made of an electrically insulating material. This enables the tank, in particular the wall in contact with the sleeve, to be made of a metallic material, since there will be no electrical contact interfering with the electrodes, which would affect the accuracy of the oil level measurement.

[0020] The invention also relates to a turbine equipped with such a tank. The turbine can be installed on an aircraft capable of performing a flight phase called "negative g".

[0021] The invention also relates to a method for assembling an electrical oil level measurement probe in a curved tank of a turbine, the method comprising the following steps: (a) fixing one or more sleeves to one or more laminated electrodes of the probe; and (b) introducing the electrodes together with the sleeves into the tank.

[0022] According to an advantageous embodiment of the invention, during the fixing step, the electrodes are straight electrodes, and during the introducing step, due to the contact of the sleeve with the wall of the tank, the electrodes gradually become arcuate.

[0023] According to an advantageous embodiment of the invention, during the fixing step, the electrodes are arcuate with a constant or non-constant curvature, and during the introducing step, the electrodes maintain their curvature.

[0024] According to an advantageous embodiment of the invention, the tank includes an opening, in particular an upper filling opening, and during the introducing step, the electrodes are introduced through said opening.

[0025] It should be understood that each detail of the following embodiments can be combined with each other detail of the other embodiments. Description of the Drawings

[0026] Figure 1 represents a turbine according to the invention;

[0027] Figure 2 shows a reservoir according to the invention;

[0028] Figure 3 shows a part of the sheath;

[0029] ​​​Figure 4 and Figure 5 depict a capacitive probe and an associated sleeve;

[0030] Figure 6 and Figure 7 show a resistive probe and an associated sleeve. Detailed Description

[0031] Figure 1 represents a simplified view of an axial turbine. In this particular instance, the axial turbine is a two - flow turbojet engine suitable for aircraft flight.

[0032] The turbojet engine 2 includes a low - pressure compressor 4, a high - pressure compressor 6, a combustion chamber 8, and one or more stages of turbines 10. In operation, the mechanical power transmitted by the turbine 10 to the rotor 12 drives the two compressors 4 and 6. Thus, the rotation of the rotor about its axis of rotation 14 enables the generation of an air flow and the progressive compression of this air flow until it enters the combustion chamber 8.

[0033] An inlet fan, commonly referred to as a fan or blower 16, is coupled to the rotor 12 and generates an air flow that divides into a main stream 18 passing through the compressor and a secondary stream 20. A speed reducer 22 can reduce the rotational speed of the blower 16 and / or the low - pressure compressor 4 relative to the associated turbine stage 10. The speed reducer 22 and the drive shaft 24 articulated by bearings 26 are lubricated by an oil circuit. A pump 28 ensures the circulation of oil in the circuit from a reservoir 30 to the reservoir 30.

[0034] Here, the position of the reservoir 30 is symbolic. In fact, the reservoir 30 can be mounted on the fan housing, and more preferably inside a stator 32 that separates the main stream 18 from the secondary stream 20, and the main stream 18 and the secondary stream 20 are respectively guided by a main - flow channel and a secondary - flow channel.

[0035] Figure 2 is a cross - sectional view of an oil reservoir 30 of a turbine 1 such as Figure 1 . The flows 18 and 20 are represented in Figure 2 . The reservoir 30 can be accommodated between a compressor housing 36 and a partition 38 that guides the secondary stream 20.

[0036] The reservoir 30 is generally a curved reservoir. The overall profile of the reservoir is arcuate to be mounted in the circular stator 32 of the turbine. The outer wall 40 or housing of the reservoir includes a curved radially - inner surface. The height of the reservoir can be at least 50 cm and can describe an angular portion of at least 10°. The radius of curvature of the wall 40 can be between 30 cm and 2 m.

[0037] ​​​​The tank 30 includes a substantially enclosed shell 42. The shell 42 can store at least 30 liters of oil 44. The shell 42 is also a curved shell. The top of the tank 30 has an opening 46 that is closed by a plug.

[0038] The tank can be a metal tank and / or can be manufactured by additive manufacturing of the ALM type. The tank can be a one-piece tank and integrated with fixing brackets and various internal functional elements (baffles, deoxygenators, etc.).

[0039] To measure and / or estimate the volume of the oil 44 in the tank, a measurement system can be introduced into the tank. The system can include an electrical probe 48 immersed in the liquid and a computer that converts the measured electrical metering into a value in liters. The probe 48 is, for example, arcuate according to a constant or non-constant radius of curvature. The probe 48 follows the curved shape of the tank. The probe 48 extends over most or the entire height of the shell 42. Thus, the probe 48 can be in contact with the oil in substantially the entire useful volume of the shell 42.

[0040] The probe 48 can include one or more electrodes that are in electrical contact with the oil. The probe 48 can be a capacitive probe, in which case the probe 48 measures the capacitance between two layered and parallel electrodes. The probe 48 can be a resistive probe, in which case the probe 48 measures the resistance of its immediate environment.

[0041] The probe 48 can be immersed in the reservoir 30 or can be inserted into a sheath 50 of the reservoir. The sheath 50 can be a metal sheath and / or can be manufactured by additive manufacturing together with the reservoir.

[0042] The sheath 50 can extend over substantially the entire height of the reservoir 30 and / or substantially the entire length of the probe 48. The sheath 50 can be perforated to facilitate the entry and exit of oil in order to contact the probe 48.

[0043] The curvature of each element (the tank 30, the outer wall 40, the wall of the sheath 50, and the probe 48) can be constant or variable. Thus, the symbols R1 and R2 in the figure represent the fact that the curvature can vary for these elements. Except for the probe 48, each element can have its own curvature independent of the other elements, and the probe 48 has a curvature imposed by the wall (the wall 40 of the tank or the wall of the sheath 50) with which the probe 48 cooperates.

[0044] Figure 3 shows an exemplary embodiment of the sheath 50. In this example, the sheath 50 consists of two U-shaped tracks 52, 54 that are parallel to each other, face each other, and are connected to each other by a grid 56.

[0045] The U-shape forms a wall that is in indirect contact with the probe 48.

[0046] Figure 4 ​​shows a capacitive probe 48. The capacitive probe 48 includes two laminated electrodes 60, 62. The electrodes 60, 62 are flexible enough to bend during or before being placed in the reservoir 30. The capacitance between the electrodes 60, 62 reflects the amount of liquid separating the electrodes 60, 62 and thus is indicative of the oil level in the reservoir. The two electrodes 60, 62 are fixed together by a connector 64 which can be attached to the reservoir at an opening ( Figure 2 at 46). The connector is also provided with an electrical connection for connecting the probe to a computer. Thus, the reservoir 30 may include a fixing element (not shown) at the opening 46 for the probe 48 to keep the probe 48 stationary regardless of the movement and vibration of the oil 44.

[0047] At least one electrode (here 60) is provided with an orifice 61 which allows the attachment of one or more sleeves 66.

[0048] The sleeve 66 surrounds the two electrodes 60, 62 while keeping the two electrodes 60, 62 at a certain distance from each other.

[0049] The sleeve may have two hemispherical ends 68, 70 which may engage in a groove of a U-shaped track ( Figure 3 ).

[0050] Fixing means 72 (pins, rivets, screws) may ensure that the sleeve 66 is fixed to the electrode 60.

[0051] A flat portion 74 may facilitate the fixing of the screw / rivet head or prevent the screw / rivet head from protruding from the sleeve 66. Alternatively, the screw / rivet head may be buried in the sleeve 66.

[0052] The shape of the sleeve 66 may be generally rectangular or oval with a longitudinal axis 76 extending transversely to the length of the electrodes 60, 62.

[0053] Figure 5 The sleeve 66 is shown separately. The sleeve 66 consists of a rectangular body, namely a cylindrical body 78 having two hemispherical ends 68, 70. The body 78 is hollowed out to receive the electrodes 60, 62 in a through cavity 80.

[0054] The cavity 80 may be provided with notches 82 for receiving the laminated electrodes 60, 62. The notches 82 may be the result of protrusions 84 protruding inwards in the through cavity 80. The protrusions 84 may have a "V" shape to facilitate the insertion of the electrodes 60, 62 and / or to impart a certain elasticity to the protrusions such that the electrodes 60, 62 can be held by wedging.

[0055] The protrusions 84 may be substantially parallel to the flat portion 74.

[0056] ​​Figure 5 The right part of ] shows a sectional view along the AA direction identified in the isometric view. In particular, it can be seen that the inner surface defining the cavity may also have a V-shape facing the protrusion 84.

[0057] The angle of the V-shape is denoted as α and can be between 150° and 170°.

[0058] Figure 6 shows a resistive probe. In this example, the probe 48 includes a single-layer electrode 60, and the single-layer electrode 60 is provided with resistors 63 distributed along the electrode. The resistor 63 has a common terminal and a free terminal, so the circuit is an open circuit. The liquid closes the circuit, and the liquid level affects the measured equivalent resistance.

[0059] The sleeve 66 can be the same as the sleeve for the capacitive probe in the previous figure. Alternatively, as Figure 6 and Figure 7 shown, the sleeve 66 may include a corner member 90 filling the through cavity 80 and a single notch.

[0060] The wedge member 90 may have a shape substantially complementary to the cavity 80. Fixing means such as by screws and nuts, pins, rivets, etc. can be provided to keep the wedge member 90 fixed to the body of the sleeve 66, thus wedging into the electrode 60.

[0061] Whether in the case of the capacitive electrode ( Figure 4 and Figure 5 ) or the resistive electrode ( Figure 6 and Figure 7 ), a number of sleeves 66 can be arranged along the electrode. For example, when the radius of curvature is small, the sleeves will be closer to each other to smooth the deformation of the electrode and avoid areas of concentrated bending stress.

[0062] It should be understood that the probe can be provided with more than two electrodes. In particular, the capacitive electrode and the resistive electrode can be combined, and one or more sleeves surround all the electrodes. In addition, other probes can be attached to the same sleeve, such as a temperature probe.

[0063] Finally, the corner member 90 can be arranged in the examples of Figure 4 and Figure 5 to fill, for example, the free space left between the electrodes 60, 62 in the middle of the cavity.

[0064] The present invention also relates to a method of installing the probe 48. First, the sleeve 66 is fixed to one or more single-layer electrodes 60, 62. Then, the assembly is introduced into the reservoir, for example, through an opening (of the opening 46 type).

[0065] During insertion, the electrodes 60, 62 are forced to bend by the contact between the sleeve and the wall 40 or the tracks 52, 54.​

[0066] Alternatively, electrodes 60, 62 may be arcuate before being introduced into reservoir 30 with sleeve 66 attached.

[0067] In addition to the advantages mentioned above, sleeve 66 electrically isolates the electrodes from the tank. A series of sleeves 66 enables a constant distance between electrodes 60, 62 to be ensured along the entire length of electrodes 60, 62. Further, the circular shape of sleeve 66 prevents stagnation or blockage of liquids that can easily flow around or inside sleeve 66 and electrodes 60, 62.

[0068] It should be noted that the present invention has been described in relation to an oil tank for a turbine, but those skilled in the art will understand that the present invention also relates to any other liquid and any other type of tank (e.g., water, fuel, liquid hydrogen, etc.).

Claims

1. An oil tank (30) for a turbine (2), comprising: - a substantially curved wall (40, 52, 54); - an electric oil level measurement probe (48), the probe (48) having one or more arcuate laminated electrodes (60, 62) following the curvature of the wall (40, 52, 54); and - at least one sleeve (66), characterized in that the sleeve (66) is mounted on the one or more laminated electrodes (60, 62) to be inserted between the one or more electrodes (60, 62) and the wall (40, 52, 54), and the sleeve (66) is fixed to the probe (48) without being attached to the wall (40, 52, 54).

2. The can (30) according to claim 1, characterized in that, The sleeve (66) has a rectangular shape with a longitudinal axis (76) transverse to the one or more laminated electrodes (60, 62).

3. The can (30) according to any one of the preceding claims, characterized in that, The sleeve (66) includes an internal notch (82) for receiving the one or more laminated electrodes (60, 62).

4. The can (30) according to the preceding claim, characterized in that, The notch (82) is formed by a protruding V-shaped projection (84).

5. The can (30) according to any one of the preceding claims, characterized in that, The sleeve (66) includes a through lumen (80) completely occupied by the one or more laminated electrodes (60, 62) and a wedge (90).

6. The can (30) according to any one of the preceding claims, characterized in that, The sleeve (66) has a generally rectangular shape with two opposite ends located in spherical portions (68, 70).

7. The can (30) according to any one of the preceding claims, characterized in that, The sleeve (66) is fixed to the probe (48) by a pin (72), a rivet (72) or a screw element (72), and the pin, rivet or screw element engages in a hole (61) of exactly one of the electrodes (60).

8. The can (30) according to any one of the preceding claims, characterized in that, The tank (30) includes a plurality of sleeves (66), and the wall (40, 52, 54) has a non-constant curvature (R1, R2), the sleeves (66) are irregularly distributed along the probe (48), and as the curvature (R1, R2) of the wall (40, 50) increases, the sleeves (66) are spaced farther apart from each other.

9. Can (30) according to any one of the preceding claims, characterized in that The wall (52, 54) is the wall of an arcuate sheath (50), and the arcuate sheath (50) is preferably formed by two U-shaped profiles (52, 54) facing each other and connected by a mesh (56).

10. The can (30) according to claim 1, characterized in that, The sleeve (66) is made of an electrically insulating material.

11. A turbine (2) for an aircraft, comprising an oil tank (30) having a substantially curved shape, characterized in that, The tank (30) is a tank according to any one of the preceding claims.

12. A method for mounting an electric oil level measurement probe (48) in a curved tank (30) of a turbine (2), the method comprising the steps of: a. fixing one or more sleeves (66) to one or more laminated electrodes (60, 62) of the probe (48); and b. introducing the one or more electrodes (60, 62) together with the one or more sleeves (66) into the tank (30).

13. The method according to claim 12, wherein In the fixing step, the one or more electrodes (60, 62) are straight electrodes, and during the introducing, due to the contact of the one or more sleeves (66) with the wall (40, 52, 54) of the tank (30), the one or more electrodes (60, 62) gradually become arcuate.

14. The method according to claim 12, wherein In the fixing step, the one or more electrodes (60, 62) are curved according to a constant or non-constant curvature (R1, R2), and during the introducing step, the one or more electrodes (60, 62) maintain their curvature (R1, R2).

15. The method according to any one of claims 12 to 14, characterized in that The can (30) includes an opening (46), in particular an upper filling opening, and during the introducing step, the one or more electrodes (60, 62) are introduced through the opening (46).

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