Sensor with adjustable measuring end position

Abstract

Sensor with adjustable measuring end position. The sensor (10') comprises a head (11) fixed to the outer surface (13) of a radially external housing (2), a measuring end (17) located opposite the head (11), and a shaft (14) connecting the head (11) to the measuring end (17). The shaft (14) has a first segment (25) integral with the head (11) and a second segment (26) comprising the measuring end (17) and slidably mounted within the first segment (25). The second segment (26) has an outer lateral face (28) equipped with a support stop (27). The sensor includes a spring that pushes the second segment (26) away from the first segment (25) to press the support stop (27) against the outer surface (20) of a ferrule (8, 9) through which the sensor (10') is mounted. This ferrule (8, 9) is fixed to the inner radial surface (5) of the radially outer housing (2), at a distance from it. Figure to be published with the abbreviation: Figure 4

Description

Title of the invention: Sensor with adjustable position of the measuring end TECHNICAL FIELD OF THE INVENTION

[0001] The technical field of the invention is that of mounting a sensor in the internal vein of a turbojet at the level of a shell mounted on a radially external casing.

[0002] The present invention relates to a means of fixing such a sensor so as to be able to fix its position with respect to the vein, and in particular whatever the variations in the radius of the radially external casing. TECHNOLOGICAL BACKGROUND OF THE INVENTION

[0003] In a turbojet engine, whether at the compressor or turbine level, blades 1 mounted on a rotor are driven in rotation within a radially external casing 2 of round section, hereinafter referred to as casing 2. The blade 3 of these blades 1 is preferably provided as close as possible to the internal part of the casing 2 in order to increase the performance and operability of the turbojet engine.

[0004] At the level of the blades 3, the internal radial surface 5 of the casing 2 of the turbojets is protected by a rigid protection designated as an abradable material support cartridge 6 and which comprises a covering of abradable material 7 intended to be located opposite the free end 4 of the blades 3. The abradable material support cartridge 6 is bordered upstream by an upstream shell 8 and downstream by a downstream shell 9 which are not parts subject to wear.

[0005] The internal radial surface of the upstream shell 8, of the abradable material coating 7 and that of the downstream shell 9 are designed to be substantially at the same level in order to form an aerodynamic vein profile.

[0006] When a sensor 10 is mounted in the internal flow path of a turbojet, it is provided at the level of one of the shells 8, 9. It is mounted on the casing 2, its head 11 being screwed onto a boss 12 provided on the external radial surface 13 of the casing 2. The sensor 10 has an intermediate part designated as a barrel 14 and which passes through the wall 15 of the casing 2 as well as the wall 16 of the shell 8, 9 so that its measuring end 17 is flush with the aerodynamic flow path.

[0007] Following studies carried out by the applicant, it has been found that due to the manufacturing process of the casing 2 and / or the deformations that it may undergo during its existence, the radius of said casing 2 may change significantly. This therefore causes the radial position of the measuring end 17 of the sensor 10 to vary by an equivalent distance inside or set back from the aerodynamic vein.

[0008] Following these studies carried out by the applicant, it was found that this variation in the position of the measuring end 17 of the sensor 10 can introduce errors into the measurements carried out by the sensor 10, in particular when the latter is a pressure sensor which measures the static pressure inside the aerodynamic vein and for which the measuring end 17 must be flush with the internal radial surface of the aerodynamic vein.

[0009] Indeed, in [Fig. 2], the measuring end 17 of the sensor 10 projects inside the aerodynamic vein, which requires taking a projecting pressure measurement which does not correspond to the static pressure elsewhere in the vein where no projecting element causes disturbances in the air flow.

[0010] Similarly, in [Fig. 3], the measuring end 17 of the sensor 10 is set back inside the upstream shell 8 relative to the aerodynamic vein, which requires a set-back pressure measurement to be taken, which again does not correspond to the static pressure elsewhere in the vein. The set-back position of the measuring end 17 of the sensor 10 generates a hollow volume 18 in which the air flow circulates little and which may be likely to generate a looping air flow.

[0011] There is therefore a need for a device making it possible to fix a sensor 10 on the external radial surface 13 of the casing 2 of a turbojet, while also making it possible to adjust the radial position of the measuring end 17 of said sensor 10 with respect to the internal radial surface 19 of the shell 8, 9 through which it is mounted. Summary of the invention

[0012] The invention offers a solution to the problems mentioned above, by adapting the barrel of the sensor in a telescopic form with two elements fitting and sliding into each other, in which a first element comprising the measuring end is pressed against the external radial surface of the ferrule by a spring exerting a pressure force on said first element when the sensor is put in place.

[0013] The solution of the invention can be adapted to any situation where a sensor must be mounted on a first element, through another element mounted on the first element and at a distance from it.

[0014] One aspect of the invention relates to a sensor comprising a head, a measuring end located opposite the head and a barrel extending along an axis Y-Y' and connecting the head to the measuring end, in which: • the barrel has a first segment attached to the head, • the barrel has a second segment having a neck-mounted end smoothing in the first segment along the Y-Y' axis and a free end, • the measuring end is located at the free end of the second segment, • the second segment has an external lateral face equipped with a support stop, and • the sensor comprises a spring housed around the second segment, between a first stop provided on the first segment and a second stop provided on an external lateral face of the second segment and said spring bearing against said first and second stops.

[0015] According to one aspect of the invention, the spring is housed along the Y-Y' axis between the first segment and the second segment, the first stop is a first confinement stop provided on an internal lateral face of the first segment, and the second stop is a second confinement stop provided on an external lateral face of the second segment.

[0016] According to another aspect of the invention, the spring is located between the first stop and the second stop, the first stop is a support stop provided on the external lateral face of the first segment and the second stop is the support stop provided on an external lateral face of the second segment.

[0017] According to a further aspect of the invention, the barrel is cylindrical.

[0018] According to one aspect of the invention, the first stop and the second stop are of shape annular.

[0019] According to another aspect of the invention, the first segment comprises a stop protruding inside said first segment, at an end located opposite the head, in that a part of the stop protruding inside said first segment has a face located opposite a face of the second confinement stop and in that the stop is located on the side of the measuring end relative to the second confinement stop.

[0020] According to a further aspect of the invention, the stopper comprises a threaded portion introduced by screwing through a corresponding threaded hole provided in the first segment, and a free end projecting outside the threaded hole inside the first segment.

[0021] According to one aspect of the invention, the sensor is a static pressure sensor.

[0022] Thanks to the invention, the radial position of the measuring end of the sensor can be adjusted, for example flush with the internal radial surface of the ferrule through which it is mounted, by simply adapting the length of the barrel of said sensor.

[0023] This radial position is further maintained, whatever the radius of the external casing, and even if this changes over time.

[0024] Indeed, the radial position of the measuring end of the sensor is indexed relative to the position of the external radial surface of the ferrule. Now the ferrule has a regular and stable external radius over time, the radial position of the end of sensor measurement can therefore be fixed reliably and durably.

[0025] The invention therefore guarantees reliable and precise measurement at the measuring end of the sensor.

[0026] The invention is advantageous in that it does not require any adaptation of the radially external casing or the ferrule through which it is mounted. The sensor of the invention can advantageously replace any sensor already in place, thus making it possible to benefit from the measurement reliability provided by the invention without having to modify the radially external casing or the ferrule through which it is mounted.

[0027] Another aspect of the invention relates to a turbojet engine comprising a radially outer casing and a radially inner shroud fixed on an inner radial surface of the radially outer casing, which turbojet engine comprises a sensor as described above and in which: • the sensor head is fixed on an external radial surface of the radially external housing; • the sensor barrel passes through a radially external wall of the casing and a radially internal wall of the shell; and • the support stop bears against an external radial surface of the radially internal shell.

[0028] According to one aspect of the invention, the turbojet engine comprises a boss fixed on the external radial surface of the radially external casing and having a threaded orifice, and the sensor has a threaded part introduced by screwing into the threaded orifice.

[0029] According to another aspect of the invention, the radially internal ferrule is an acoustic attenuation part.

[0030] Thanks to the invention, such a turbojet is more reliable, because the measurements taken by the sensor are more precise than those taken by previous sensors.

[0031] The invention and its various applications will be better understood by reading the following description and examining the accompanying figures. BRIEF DESCRIPTION OF THE FIGURES

[0032] The figures are presented for information purposes only and in no way limit the invention.

[0033] [Fig.l] [Fig.l] is a schematic perspective sectional view of a crankcase external turbojet casing at the level of an abradable material support cartridge bordered by upstream and downstream shrouds, a blade being shown facing the abradable material support cartridge and a sensor being mounted on the external radial surface of the radially external casing, through the upstream shroud.

[0034] [Fig.2] [Fig.2] is a detail view of the part circled in [Fig.l], in in which the measuring end of a sensor according to the prior art projects inside the aerodynamic vein.

[0035] [Fig.3] [Fig.3] is a detail view of the part circled in [Fig.l], in in which the measuring end of a sensor according to the prior art is set back from the aerodynamic vein.

[0036] [Fig.4] [Fig.4] is a detail view of the part circled in [Fig.l], in in which the sensor is a sensor according to the invention, represented in a simplified manner, and the measuring end of which is flush with the internal radial surface of the aerodynamic vein.

[0037] [Fig.5] [Fig.5] is a detail view of the circled portion in [Fig.4], illustrating a first embodiment of the sensor according to the invention.

[0038] [Fig.6] [Fig.6] is a detail view of the circled portion in [Fig.4], illustrating a second embodiment of the sensor according to the invention. DETAILED DESCRIPTION

[0039] By convention, in the present application, the terms "upstream" and "downstream" are defined relative to the direction of air circulation in the turbomachine. Thus, upstream is located on the air inlet side, while downstream is located on the air outlet side.

[0040] As shown in [Fig.l], at the level of certain rotating blades 1 of the turbojet, the internal radial surface 5 of the casing 2 may comprise a support cartridge of abradable material 6 fixed on the internal radial surface 5 of the casing 2 and comprising a layer of abradable material 7 which is hollowed out by the free end 4 of the blade 3 of a blade 1 in the event of contact with the latter.

[0041] The casing 2 is generally in the form of a solid of revolution comprising substantially cylindrical zones and substantially conical zones. In the figures, it is formed of an air inlet casing 2a, a fan casing 2b and an intermediate casing 2c.

[0042] Upstream, the abradable material support cartridge 6 is bordered by an upstream ferrule 8, and by a downstream ferrule 9. These ferrules 8, 9 are fixed on the internal radial surface 5 of the casing 2, at a distance from the latter. They can be designated as radially internal ferrules. The ferrules 8, 9 are preferably acoustic attenuation parts.

[0043] The abradable material support cartridge 6, the upstream shell 8 and the downstream shell 9 are usually cylindrical in shape. The abradable material support cartridge 6, the upstream shell 8 and the downstream shell 9 are centered inside the casing 2 and extend along the longitudinal axis along which the turbomachine extends.

[0044] A sensor 10, 10', for example a static pressure sensor, is fixed to the casing 2 at the level of one of the ferrules 8, 9.

[0045] The sensor 10' according to the invention comprises a head 11 and a measuring end 17 located at the opposite end of the head 11 and connected to the latter by an intermediate part usually referred to as barrel 14.

[0046] The head 11 is for example fixed on a boss 12, itself fixed on the external radial surface 13 of the casing 2, for example by gluing, welding, brazing or bolting. For this purpose, the boss 12 has for example a threaded orifice 21 and the head 11 of the sensor 10' then has a threaded part 22 which is introduced by screwing into the threaded orifice 21 of the boss 12, the thread of the threaded orifice 21 of the boss 12 and the thread of the threaded part 22 being of course complementary.

[0047] The measuring end 17 is a distal end of the sensor 10', located opposite the head 11, at which a measurement is carried out by the sensor 10'.

[0048] The barrel 14 is an intermediate part of the sensor 10' which extends along an axis Y-Y' and which connects the measuring end 17 to the head 11 of the sensor 10'. The barrel 14 is preferably of generally cylindrical shape. It is introduced through a first bore 23 provided in the wall 15 of the casing 2 and a second bore 24 provided in the wall 16 of the shell 8, 9 at the level of which the sensor 10' is mounted.

[0049] According to the invention, the barrel 14 is telescopic and comprises at least two parts, namely a first segment 25 which is integral with the head 11 and a second segment 26 comprising the measuring end 17. The second segment 26 is mounted to slide along the axis Y-Y' relative to the first segment 25, the second segment 26 being housed partially inside the first segment 25.

[0050] Preferably, the threaded part 22 of the head 11 of the sensor 10' is continuous with the first segment 25 of the barrel 14.

[0051] The internal diameter of the threaded orifice 21 of the boss 12 is preferably greater than the external diameter of the first segment 25 so that the first segment 25 can be introduced through said threaded orifice 21.

[0052] According to the invention, the second segment 26 comprises a support stop 27 on its external lateral face 28. This support stop 27, preferably of annular shape, is designated thus because it is intended to be located in abutment against the external radial surface 20 of the ferrule 8, 9 at the level of which the sensor 10' is mounted. The support stop 27 has a diameter greater than that of the second bore 24 provided in the wall 16 of the ferrule 8, 9. It is preferably in the form of a 360-degree ring and is for example fixed on the external lateral face 28 of the second segment 26 by gluing, welding or brazing.

[0053] The sensor 10' according to the invention comprises a spring 29 which, when the sensor 10' is mounted in place, is compressed and exerts a thrust force on the second segment 26 aimed at moving it away from the first segment 25 in a direction parallel to the axis Y-Y', so as to press the support stop 27 against the external radial surface 20 of the ferrule 8, 9.

[0054] This abutting of the second segment 26 against the ferrule 8, 9 makes it possible to fix the radial position of the measuring end 17 of the sensor 10'. By adjusting the length of the second segment 26 relative to the thickness of the wall 16 of the ferrule 8, 9, it is therefore possible to adjust the radial position of the measuring end 17 of the sensor 10' relative to the aerodynamic vein. In the case where the sensor 10' according to the invention is a static pressure sensor, it is therefore possible to adjust the radial position of the measuring end 17 of the sensor 10' so that it is flush with the aerodynamic vein.

[0055] According to a first embodiment of the invention shown schematically and simplified in [Fig.5], the spring 29 is preferably housed radially between the first segment 25 and the second segment 26.

[0056] According to this first embodiment, the spring 29 is mounted around the second segment 26 and housed inside the first segment 25, at the level of the part of the second segment 26 which is housed inside the first segment 25.

[0057] According to the first embodiment, when the sensor 10' is mounted on the casing 2, the spring 29 is preferably compressed between a first confinement stop 30 fixed on the internal lateral face 31 of the first segment 25 and a second confinement stop 32 fixed on the external lateral face 28 of the second segment 25, preferably by gluing, welding or brazing. These confinement stops 30, 32 are designated thus because they delimit a volume in which the spring 29 is housed.

[0058] According to this embodiment, the first confinement stop 32 and the second confinement stop 32 are preferably each of annular shape.

[0059] According to the first embodiment, at its end located opposite the head 11, the first segment 25 preferably comprises at least one stop 33 projecting inside the first segment 25. This stop 33 is dimensioned so as to prevent the second confinement stop 32 of the second segment 26 from coming out of the first segment 25 when the second segment 26 slides relative to the first segment 25.

[0060] According to this embodiment, the stop stop 33 preferably comprises a threaded portion 34 introduced by screwing through a threaded orifice 35 provided in the first segment 25, and a free end 36 projecting outside the threaded orifice 35, inside the first segment 25, beyond the internal lateral face 31 of the first segment 25, so as to form an obstacle for the passage of the second confinement stop 32 of the second segment 26. For this purpose, a part of the stop stop portion 33 projecting inside said first segment 25 preferably has a face located opposite a face of the second confinement stop 32 and the stop stop 33 is preferably located above the second confinement stop 32. The thread of the threaded orifice 35 of the first segment 25 and the thread of the threaded portion 34 are of course complementary.

[0061] According to the first embodiment, the sensor 10' according to the invention preferably comprises two stops 33 facing each other in the first segment 25.

[0062] According to a second embodiment of the invention shown schematically and simplified in [Fig. 6], the first segment 25 comprises a support stop 37 provided on the external lateral face 38 of the first segment 25, preferably at the upper free end thereof. This support stop 37 is designated as such because it serves as a support for the spring 29. It can for example be fixed by gluing, welding or brazing on the external lateral face 38 of the first segment 25. It can be in one piece with the upper part of the first segment 25, for example in the form of a shoulder thereof. The support stop 37 is preferably annular in shape, for example in the form of a 360-degree ring.

[0063] According to this embodiment, the spring 29 is preferably mounted around the second segment 26 and housed between the support stop 37 provided on the external lateral face 38 of the first segment 25 and the support stop 27 provided on the external lateral face 28 of the second segment 26.

[0064] According to the second embodiment, when the sensor 10' is mounted on the casing 2, the spring 29 is preferably compressed between the support stop 37 and the bearing stop 27, the bearing stop 27 being preferably above the spring 29, while the support stop 37 is preferably below the spring 29.

[0065] According to the second embodiment, the sensor 10' comprises a holding device 39 making it possible to hold the first segment 25 together with the second segment 26. This holding device 39 may for example comprise a casing or a deformable sleeve, in particular with bellows, at least partially enveloping the spring 29, the support stop 37 and the support stop 27, which also makes it possible to protect the spring 29.

[0066] The invention also relates to a turbojet engine equipped with a sensor 10' according to the invention at a shell 8, 9 fixed to the internal radial surface 5 of the casing 2. The head 11 of the sensor 10' is fixed to the external radial surface 13 of the casing 2, for example by screwing using the boss 12 as described previously, while the barrel 14 of the sensor 10' passes through the wall 15 of the casing 2 and the wall 16 of the shell 8, 9 at which the sensor 10' is mounted. The support stop 27 is positioned in abutment against the external radial surface 20 of the shell 8, 9, while the length of each of the segments 25, 26 of the barrel 14 is dimensioned so that the measuring end 17 of the sensor 10' is located at the desired radial position, for example at the internal radial surface 19 of the shell 8, 9, flush with the internal vein of the turbojet.

[0067] In the case of the first embodiment of the sensor 10', each stop 33 is placed in the first segment 25 after insertion of the second segment 26 into the first segment 25.

[0068] Although in the figures the sensor 10' is shown mounted at an upstream ferrule 8, it can also be mounted at a downstream ferrule 9. It is obvious to those skilled in the art that, in general, the sensor 10' according to the invention can be mounted on a first element - here the casing 2 - through another element - here the ferrule 8, 9 - mounted on the first element and at a distance from it.

[0069] Unless otherwise specified, the same element appearing in different figures has a single reference.

Claims

Claims

1. Sensor (10') comprising a head (11), a measuring end (17) located opposite the head (11) and a barrel (14) extending along an axis Y-Y' and connecting the head (11) to the measuring end (17), characterized in that: - the barrel (14) comprises a first segment (25) integral with the head (11), - the barrel (14) comprises a second segment (26) having an end slidably mounted in the first segment (25) along the axis Y-Y' and a free end, - the measuring end (17) is located at the free end of the second segment (26), - the second segment (26) has an external lateral face (28) equipped with a support stop (27), and - the sensor (10') comprises a spring (29) housed around the second segment (26), between a first stop (30, 37) provided on the first segment (25) and a second stop (32,27) provided on an external lateral face (28) of the second segment (26) and said spring (29) bearing against said first and second stops (30, 37, 32, 27).,

2. Sensor (10') according to claim 1, characterized in that the spring (29) is housed along the axis YY' between the first segment (25) and the second segment (26), in that the first stop is a first confinement stop (30) provided on an internal lateral face (31) of the first segment (25), and in that the second stop is a second confinement stop (32) provided on an external lateral face (28) of the second segment (26).

3. Sensor (10') according to claim 1, characterized in that the spring (29) is located between the first stop (37) and the second stop (27), in that the first stop (37) is a support stop (37) provided on the external lateral face (38) of the first segment (25) and in that the second stop (27) is the support stop (27) provided on an external lateral face (28) of the second segment (26).

4. Sensor (10') according to claim 1 or claim 2, characterized in that the barrel (14) is cylindrical.

5. Sensor (10') according to any one of the preceding claims, characterized in that the first stop (30, 37) and the second stop (32, 27) are annular in shape.

6. Sensor (10') according to claim 2, characterized in that the first segment (25) comprises a stop (33) projecting inside said first segment (25), at an end located opposite the head (11), in that a part of the stop part (33) projecting inside said first segment (25) has a face located opposite a face of the second confinement stop (32) and in that the stop (33) is located on the side of the measuring end (17) relative to the second confinement stop (32).

7. Sensor (10') according to claim 5, characterized in that the stop (33) comprises a threaded portion (34) introduced by screwing through a corresponding threaded orifice (35) provided in the first segment (25), and a free end (36) projecting outside the threaded orifice (35) inside the first segment (25).

8. Sensor (10') according to any one of the preceding claims, characterized in that the sensor (10') is a static pressure sensor.

9. Turbojet engine comprising a radially outer casing (2) and a radially inner shroud (8, 9) fixed on an inner radial surface (5) of the radially outer casing (2), characterized in that it comprises a sensor (10') according to any one of the preceding claims and in that: - the head (11) of the sensor (10') is fixed on an outer radial surface (13) of the radially outer casing (2); - the barrel (14) of the sensor (10') passes through a wall (15) of the radially outer casing (2) and a wall (16) of the radially inner shroud (8, 9); and - the support stop (27) bears against an outer radial surface (20) of the radially inner shroud (8, 9).

10. Turbojet according to claim 9, characterized in that it comprises a boss (12) fixed on the external surface (13) of the radially external casing (2) and having a threaded orifice (21), and in that the sensor (10') has a threaded part (22) introduced by screwing into the threaded orifice (21).

11. Turbojet according to claim 9 or 10, characterized in that the radially internal ferrule (8, 9) is an acoustic attenuation part.

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