ASSEMBLY COMPRISING A LOW-PRESSURE TURBINE AND A DEVICE FOR DETECTING SEAL PLATES AND METHOD FOR DETECTING SEAL PLATES OF A LOW-PRESSURE TURBINE

Abstract

ASSEMBLY COMPRISING A LOW-PRESSURE TURBINE AND A SEAL DETECTION DEVICE AND METHOD FOR DETECTING SEAL PLATES OF A LOW-PRESSURE TURBINE The assembly comprises a low-pressure turbine and a seal detection device (1) (P). The turbine comprises a housing and a stage 1 comprising sealing sectors separated by inter-sector openings. The device (1) comprises a frame (10), a guide conduit, a pin which includes a pin body (16) sliding axially inside the guide conduit and a contact end (18) – such that when the bearing surface (11) of the frame is in contact with the upstream periphery of the low pressure turbine casing, the contact end is downstream of an inter-sector opening of stage 1 of a low pressure turbine – and a gauge (19) which is translationally fixed to the pin body and movable between a first and a second position.Figure for the abridged version: figure 4.

Description

Title of the invention: ASSEMBLY COMPRISING A LOW PRESSURE TURBINE AND A DEVICE FOR DETECTING SEALING PLATES AND METHOD FOR DETECTING SEALING PLATES OF A LOW PRESSURE TURBINE TECHNICAL FIELD OF THE INVENTION

[0001] The present invention relates to the field of aeronautics and particularly to the field of mounting low pressure turbine sealing sectors.

[0002] The invention relates to an assembly comprising a low pressure turbine and a device for detecting low pressure turbine sealing plates. Another object of the invention is a method for detecting sealing plates of a low pressure turbine. TECHNOLOGICAL BACKGROUND OF THE INVENTION

[0003] An aeronautical turbomachine conventionally comprises a compressor, a combustion chamber and a turbine. The role of the turbine is to ensure the rotational drive of the compressor by taking part of the pressure energy from the hot gases leaving the combustion chamber and transforming it into mechanical energy.

[0004] A compressor consists of a rotating part, the rotor comprising an axis of rotation, a fixed part, the stator, and a casing, the casing, the casing and the stator being integral with each other. The rotor comprises a drum consisting of an assembly of several discs on which rotating blades are circumferentially fixed. The stator consists of a plurality of fixed blades (because they do not rotate around the axis of rotation of the rotor but can be mobile in rotation along their own axis) fixed circumferentially on the casing or on shells. Each row of fixed blades of the stator, called rectifiers, constitutes a rectifier or distributor. A row of moving blades and a row of fixed blades form a compressor stage.

[0005] Each compressor stage has sealing sectors to prevent air leaks from the main air stream to the casing of the low pressure turbine. In order to ensure sealing between adjacent sectors of stage 1 of a low pressure turbine, it is known to use metal plate-type parts between the sectors. Stage 1 is the upstream stage of the low pressure turbine, namely the first stage encountered by the air flow which flows from upstream to downstream at inside the low pressure turbine.

[0006] [Fig.l] illustrates a stage 1 sealing sector SI of a low-pressure turbine. Platelets P are inserted into slots machined in the sector SI. The platelets P cover the separation between two adjacent sealing sectors. [Fig.2] illustrates a sectional view along a plane passing through the axis of rotation of the turbine of the sealing sector illustrated in [Fig.l]. The platelet P is positioned between two adjacent sealing sectors, thus improving the sealing of the air stream.

[0007] During assembly, the various rotor and stator stages are assembled and the low-pressure turbine module is then lifted. Loss of pads between the sealing sectors of stage 1 of the low-pressure turbine is regularly observed. The module must then be completely disassembled to replace the missing pads. The disassembly operation is very time-consuming and can double the time required for assembly of the low-pressure turbine.

[0008] In addition, during operation, disengagement or loss of platelets has also been observed. Such disengagement is very dangerous, involving for example the following risks: - the seal between the sectors is no longer guaranteed, which impacts the lifespan of the surrounding parts; - the presence of a damaged object (“Foreign Object Damaged” in English terminology) in the turbine, which can generate risks of damage to the turbine itself.

[0009] Currently, it is not possible to detect the presence of the stage 1 sealing pads after assembly of the pressure turbine, because the pads are not visible when the low pressure turbine is mounted. Summary of the invention

[0010] The invention provides a solution to the problems mentioned above by proposing a tool for detecting stage 1 sealing pads of a low-pressure turbine which makes it possible to check the positioning of the pads without the need to dismantle the low-pressure turbine.

[0011] To this end, a first aspect of the invention relates to an assembly comprising a low pressure turbine and a device for detecting sealing plates of stage 1 of a low pressure turbine, the low pressure turbine having an axis of rotation X and comprising: - a casing, said casing comprising an upstream periphery; - a low pressure turbine stage 1 including sealing sectors separated by inter-sector openings; - the device comprising: - a frame comprising: • an upstream face; • a downstream face comprising a support surface; - a guide duct extending from the upstream wall to the downstream wall and passing through the frame to the downstream face; - a job including: • a pin body extending between an upstream portion and a downstream portion and sliding axially inside the guide duct and • a contact branch extending from the downstream portion of the rod body to a contact end, - so that when the bearing surface is in contact with the upstream periphery of the low pressure turbine casing, the contact end is downstream of an inter-sector opening of stage 1 of a low pressure turbine; - a gauge integral in translation with the gauge body, the gauge being mobile between : • a first position corresponding to the presence of a sealing plate and in which the contact end rests on the sealing plate; • a second position corresponding to the absence of a sealing plate; - each position of the gauge corresponding to an axial position of the gauge body.

[0012] In the description, the terms "upstream" and "downstream" are defined with respect to the direction of air flow from the air inlet into the low pressure turbine to the air outlet from the low pressure turbine.

[0013] The upstream periphery of the low-pressure turbine casing is understood to mean an element delimiting the casing upstream. For example, the upstream periphery of the low-pressure turbine casing comprises an upstream face of the low-pressure turbine casing and a radially internal face of the low-pressure turbine casing. In other words, the low-pressure turbine casing extends radially and axially from its upstream periphery.

[0014] The term "bearing surface" means a face of the frame having a shape adapted to fit the upstream periphery of the low-pressure turbine casing. The bearing surface can therefore bear both radially and axially on the upstream periphery of the low-pressure turbine casing. The shape of the bearing surface makes it possible to position the detection tool so as to place the contact branch close to an opening between the sealing sectors.

[0015] The sealing sectors are arranged in circumferential rows around the axis of rotation X. Stage 1 comprises a plurality of such sectors, an inter- sectors separating two adjacent sectors.

[0016] If a sealing plate is correctly positioned between the two sealing sectors, the contact end is in axial abutment against the sealing plate. The gauge is then in a first position corresponding to a correctly positioned sealing plate.

[0017] If the plate is not in place, the contact end is not stopped by the plate. The gauge body can therefore rise upstream of the frame, for example under the pressure of a spring or another element exerting a force upstream. The second position of the gauge is then upstream of the first position of the gauge. This second position of the gauge corresponds to an absent or incorrectly positioned sealing plate. The spring can for example be replaced by manual force or by the pressure of the air blown against the spring.

[0018] The gauge is therefore movable between two positions, one corresponding to a plate in place and the other corresponding to an absent or incorrectly positioned plate.

[0019] Thanks to the assembly according to one aspect of the invention, it is therefore possible to check the presence of inter-sector sealing plates of a stage 1 of a low-pressure turbine without needing to dismantle the low-pressure turbine or, in other words, in the assembled state.

[0020] In one or more embodiments, the bearing surface comprises a first surface opposite the upstream face and a second surface forming with the first surface an angle of between 60 and 120 degrees; this arrangement makes it possible to position the detection device in both axial and radial support against the upstream periphery of the casing.

[0021] In one or more embodiments, the guide duct comprises a cavity extending from the upstream face of the frame to a stop wall; - said device further comprising a spring at least partially housed in the cavity, said spring having an upstream end and a downstream end in contact with the stop wall, - the upstream end of the spring being integral in translation with the gauge body, the gauge being fixed to the upstream portion of the gauge body and being at least partially housed in the cavity, each position of the gauge corresponding to a different elongation of the spring.

[0022] The spring is for example a helical spring or a leaf spring or any type of spring that can be partially housed in the cavity. Thanks to the fact that the spring is both in axial abutment and integral with the rod body, it pushes the rod body upstream, making it movable between two or more positions, each position of the rod being associated with a position of the gauge. The empty length of the spring is for example greater than the axial length of the cavity in which the spring is by entially housed, so as to push the gauge and the gauge body upstream when the contact end is engaged downstream of the sealing sectors.

[0023] In one or more embodiments, the upstream portion of the gauge body is threaded and the gauge is fixed to the gauge body by a nut; this arrangement makes it possible to simply and effectively secure the gauge body and the gauge.

[0024] In one or more embodiments, the gauge is movable between three positions; the third position of the gauge is associated with poor positioning of the device according to the first aspect of the invention, the contact end not being opposite a space between sealing sectors. The third position of the gauge therefore makes it possible to identify poor positioning of the detection tool, because the contact end may well be located downstream of the sealing sectors but not opposite an inter-disc opening.

[0025] In one or more embodiments, the contact branch extends from the downstream portion of the rod body, said contact branch comprising: - a first part extending from the downstream portion of the rod body and forming with the rod body an angle of between 90 and 180 degrees; - a second part extending from the first part to the contact end and being parallel to the rod body.

[0026] This arrangement of the contact branch makes it possible to position the contact end downstream of the low-pressure turbine stage 1. The contact end is therefore located close to the inter-sector opening and, under the action of the spring, it is in axial abutment with the sealing plate or pushed upstream if the sealing plate is not present.

[0027] In one or more embodiments, the gauge comprises an upstream face and when said gauge is in the first position the upstream face of the gauge is aligned with the upstream face of the frame.

[0028] This arrangement makes it possible to associate an axial position of the gauge with the correct positioning of the sealing plate.

[0029] In one or more embodiments, the gauge comprises an upstream face and when said gauge is in the second position the upstream face of the gauge is upstream of the upstream face of the frame.

[0030] This arrangement makes it possible to associate an axial position of the gauge with the absence of the sealing plate.

[0031] In one or more embodiments, the gauge comprises an upstream face and, when said gauge is in the third position, the upstream face of the gauge is downstream of the upstream face of the frame.

[0032] This arrangement makes it possible to associate an axial position of the gauge with the poor positioning of the device according to the first aspect of the invention.

[0033] In one or more embodiments, the contact branch has a thickness less than the distance between two adjacent sealing sectors. In other words, the contact branch comprises a narrowing.

[0034] This allows the contact branch to translate between the two sealing sectors. in the absence of the sealing plate, by increasing the gap between the first and second position of the gauge.

[0035] A second aspect of the invention relates to a method for detecting the presence of a stage 1 sealing plate of a low pressure turbine, said method comprising the steps of: Positioning of a detection tool including: a frame comprising: - an upstream face; - a downstream face comprising a support surface; a guide duct extending from the upstream wall to the downstream wall and passing through the frame to the downstream face; a freelance job including: a pin body extending between an upstream portion and a downstream portion and sliding in the guide duct and a contact branch extending from the downstream portion of the pin body to a contact end, such that when the bearing surface is in contact with an upstream periphery of a low pressure turbine casing, the contact end is downstream of an inter-sector sealing opening of stage 1 of a low pressure turbine; • a gauge integral in translation with the gauge body; the positioning being carried out so as to place the bearing face in radial and axial support on the upstream periphery of a low pressure turbine casing; Detection of the gauge position, the gauge being movable between: • a first position corresponding to the presence of a sealing plate and in which the contact end rests on the sealing plate; • a second position corresponding to the absence of a sealing plate; each position of the gauge corresponding to an axially different position of the gauge body.

[0036] Thanks to the method according to the second aspect of the invention, it is possible to detect in a simple and reliable manner the presence of sealing plates in a stage 1 of a low pressure turbine.

[0037] The device positioned during the positioning step may comprise one or several characteristics of the device of the assembly according to the first aspect of the invention, according to all technically possible combinations.

[0038] The invention and its various applications will be better understood upon reading the following description and examining the accompanying figures. BRIEF DESCRIPTION OF THE FIGURES

[0039] Other advantages and characteristics of the invention will appear on reading the following description, illustrated by the figures among which: - [Fig.l] illustrates a side view of a sealing sector comprising sealing plates according to the state of the art; - [Fig.2] illustrates a sectional view of a low pressure turbine according to the state of the technique; - [Fig.3] illustrates an embodiment of a detection device of sealing plates of an assembly according to one aspect of the invention; - [Fig.4] illustrates an example of an assembly according to one aspect of the invention; - [Fig.5a] illustrates a sectional view showing the position of the gauge of the device of an assembly according to one aspect of the invention in the event of the presence of the sealing plate; - [Fig.5b] illustrates a sectional view showing the position of the gauge of the device of an assembly according to one aspect of the invention in the absence of the sealing plate; - [Fig.6a], [Fig.6b] and [Fig.6c] each illustrate a view of an assembly according to an aspect of the invention with different gauge positions; - [Fig.7] illustrates another view of an assembly according to one aspect of the invention; - [Fig.8] schematically illustrates the steps of an embodiment of a method according to a second aspect of the invention. DETAILED DESCRIPTION

[0040] Figures 1 and 2 have been described in relation to the state of the art.

[0041] Unless otherwise specified, the same element appearing in different figures has a single reference.

[0042] For the understanding of the invention, the radial R, tangential T and axial A orientations will be adopted according to the reference RTA indicated in the figures, the tangent T and axial A axes of which extend in a horizontal plane according to the orientation in the figures. The axial axis A is parallel to an axis of rotation X of an aircraft turbomachine comprising the axial clearance control system according to one aspect of the invention.

[0043] [Fig. 3] illustrates a sectional view of an embodiment of a device 1 for detecting sealing plates of an assembly according to one aspect of the invention. The section illustrated in [Fig. 3] is along a plane passing through the axis of rotation of the turbine low pressure.

[0044] According to the example illustrated in [Fig. 3], the device 1 comprises a frame 10 comprising a bearing surface 11 and an upstream face 13. The bearing surface 11 comprises a first surface 11a opposite the upstream face 13 and a second surface 11b substantially perpendicular to the first surface 11a. The bearing surface 11 is adapted to bear radially and axially on a radially internal periphery of a low-pressure turbine casing. The frame 10 further comprises a guide duct 15 which comprises a cavity 12 extending from the upstream face 13 downstream to a stop wall 12b. A spring 14 is at least partially housed in the cavity 12. The downstream end of the spring 14b abuts against the stop wall 12b. The upstream end 14a of the spring is fixed to a gauge 19 and to a rod body 16.

[0045] The rod body 16 comprises an upstream portion 16a and a downstream portion 16b. Thanks to a second part of the conduit 15 extending from the downstream wall 12b of the cavity 12, the rod body 16 can slide axially in the frame 10 by the effect of the spring 14.

[0046] In the example illustrated in [Fig. 3], the upstream portion of the gauge body 16 has a threaded part allowing a nut 20 to be screwed. The nut 20 secures the gauge body 16 and the gauge 19 in axial translation.

[0047] The rod body 16 further comprises a contact branch 17. The contact branch 17 comprises a first part 17.1 extending from the downstream part 16b of the rod body and a contact branch 17.2 extending from the first part 17.1 to a contact end 18. Once the device 1 is positioned, the contact end 18 is located opposite the space between sealing sectors.

[0048] The first part 17.1 forms with the downstream part of the rod body an angle of between 90 degrees and 180 degrees. This angle makes it possible to position the contact end downstream of an inter-sector opening of stage 1 of the low pressure turbine.

[0049] [Fig.4] illustrates an embodiment of an assembly according to one aspect of the invention comprising a device 1, for example as described with reference to [Fig.3], and a low pressure turbine.

[0050] The low pressure turbine has an axis of rotation X and a casing 2. The low pressure turbine further comprises a low pressure turbine stage 1 comprising a circumferential row of sealing sectors S, an abradable AT forming part of the sealing sectors S and a row of blades A. The blades A are mounted in circumferential rows on a rotor disc not shown in [Fig.4].

[0051] The P plates are mounted in the inter-sealing sector openings.

[0052] The casing 2 is delimited upstream by an upstream periphery 2.1. The upstream periphery 2.1 comprises an upstream face 2.1a substantially perpendicular to the axis X and an internal radial face 2.1r. The bearing surface 11 of the device 1 bears both radially and axially on the periphery. This positioning as well as the dimensioning of the elements of the device 1 allows the contact end to be positioned downstream of an inter-seal sealing opening.

[0053] In the example illustrated in [Fig.4], the contact end 18 is furthermore opposite an inter-sector opening in which a sealing plate P is well positioned. The contact end 18 is then in axial abutment against the plate P, which blocks the elongation of the spring 14 upstream. It follows that, in the presence of a plate P well positioned in an inter-sector opening, the upstream face 19a of the gauge is aligned with the upstream face 13 of the frame 10 of the device 1.

[0054] This position of the gauge makes it possible to determine the presence of a P plate in the inter-sealing sector opening, without the need to dismantle the low pressure turbine.

[0055] [Fig.5a] illustrates a sectional view of an embodiment of an assembly according to one aspect of the invention. The contact end 18 is positioned in the inter-sector opening. The plate P is well positioned and it comes into axial abutment against the contact end 18, blocking the thrust of the spring 14 towards the upstream. The upstream face 19a of the gauge 19 is aligned with the upstream face of the frame 13. In other words, the axial gap between the upstream face of the gauge 19a and the upstream face of the frame 13 is zero.

[0056] [Fig.5b] illustrates a sectional view similar to that illustrated in [Fig.5a], but in the absence of a sealing plate P in the inter-sector opening. In this case, the contact end 18 is not stopped by the sealing plate and the spring pushes the rod body 16 upstream until the contact end 18 comes into contact with another element, for example a part of the casing 2. In this case, the contact branch 17 penetrates at least partially into the inter-sector opening. In addition, the upstream face 19a of the gauge 19 is found, pushed by the spring 14, upstream of the upstream face 13 of the frame 10. In other words, in the absence of the plate P, there is an axial gap L between the upstream face of the gauge 19a and the upstream face of the frame 13, with the upstream face of the gauge 19a upstream of the frame.

[0057] Figures 6a, 6b and 6c each illustrate a three-dimensional view from upstream of an embodiment of an assembly according to one aspect of the invention.

[0058] In the case of [Fig.6a], the upstream face of the gauge is positioned downstream of the upstream face of the frame. This corresponds to a contact end which is not opposite an inter-sealing sector opening. For example, the contact end may be in axial abutment with another portion of the turbine ring. The device 1 must therefore be repositioned.

[0059] [Fig.6b] represents the case illustrated with reference to [Fig.5a]. [Fig.6c] represents the case illustrated with reference to [Fig.5b].

[0060] [Fig.7] illustrates a three-dimensional view from downstream of an embodiment of an assembly according to one aspect of the invention. In the example illustrated in [Fig.7], the second part 17.2 of the contact branch has a narrowing 17.2a to allow its passage into the inter-sector opening.

[0061] [Fig. 7] also illustrates that the conduit 15 passing through the frame 10 may comprise a downstream part 15.1 open radially outwards. The radially external opening of the downstream part 15.1 of the conduit allows the axial sliding of the first part 17.1 of the contact branch 17.

[0062] [Fig.8] schematically illustrates an embodiment of a method 70 for detecting the presence of stage 1 sealing plates of a low pressure turbine according to another aspect of the invention.

[0063] In the example illustrated in [Fig.8], the method 70 comprises a first step 71 of positioning a device 1 for detecting the presence of sealing plates according to the first aspect of the invention.

[0064] During the positioning step, the tool 1 is positioned in axial and radial support on the upstream periphery of the low-pressure turbine casing.

[0065] The method 70 according to the example illustrated in [Fig.8] further comprises a step 71 of detecting the position of the gauge 19 of the device 1. The position of the gauge being linked to the presence or absence of the sealing plate P, the detection of its position makes it possible to determine whether the plate P is correctly positioned.

[0066] Steps 71 and 72 can then be repeated for each low pressure turbine stage 1 intersector opening.

Claims

Claims

1. Assembly comprising a low pressure turbine and a device (1) for detecting sealing plates (P) of stage 1 of a low pressure turbine, the low pressure turbine having an axis of rotation X and comprising: - a casing, said casing comprising an upstream periphery; - a low pressure turbine stage 1 comprising sectors sealing separated by inter-sector openings; - the device (1) comprising: - a frame (10) comprising: • an upstream face (13); • a downstream face comprising a bearing surface (11); - a guide duct (15) extending from the upstream wall (13) towards the downstream and passing through the frame (13) to the downstream face; - a job including: • a pin body (16) extending between an upstream portion (16a) and a downstream portion (16b) and sliding axially inside the guide duct (15) and • a contact branch (17) extending from the downstream portion (16b) of the rod body to a contact end (18), - so that when the bearing surface (11) is in contact with the upstream periphery of the low pressure turbine casing, the contact end (18) is downstream of an inter-sector opening of stage 1 of a low pressure turbine; - a gauge (19) integral in translation with the gauge body (16), said gauge (19) being movable between: • a first position corresponding to the presence of a sealing plate (P) and in which the contact end (18) is supported on the sealing plate (P); • a second position corresponding to the absence of a sealing plate (P); - each position of the gauge (19) corresponding to an axial position of the gauge body (16).

2. Assembly according to the preceding claim in which the bearing surface (11) comprises a first surface (11a) opposite the upstream face (13) and a second surface (11b) forming with the first surface (11a) an angle of between 60° and 120°.

3. Assembly according to one of the preceding claims in which the guide duct (15) comprises a cavity (12) extending from the upstream face (13) of the frame (10) to a stop wall (12b); - said device (1) further comprising a spring (14) at least partially housed in the cavity (12), said spring (14) having an upstream end (14a) and a downstream end (14b) in contact with the stop wall (12b), - the upstream end of the spring (14a) being integral in translation with the rod body, the gauge (19) being fixed to the upstream portion of the rod body and being at least partially housed in the cavity (12), each position of the gauge (19) corresponding to a different elongation of the spring (14).

4. Assembly according to one of the preceding claims in which the upstream portion of the gauge body (16a) is threaded and the gauge (19) is fixed to the gauge body (16) by a nut.

5. Assembly according to one of the preceding claims in which the gauge (19) comprises an upstream face (19a) and when said gauge is in the first position the upstream face of the gauge is aligned with the upstream face (13) of the frame (10).

6. Assembly according to one of the preceding claims in which the gauge (19) comprises an upstream face (19a) and when said gauge (19) is in the second position the upstream face (19a) of the gauge (19) is upstream of the upstream face (13) of the frame (10).

7. Assembly according to the preceding claim in which the gauge (19) is movable between three positions and in the third position the contact end (18) is not opposite a region separating two sealing sectors of stage 1 of the low pressure turbine.

8. Assembly according to the preceding claim in which the gauge (19) comprises an upstream face (19a) and when said gauge (19) is in the third position, the upstream face (19a) of the gauge (19) is downstream of the upstream face (13) of the frame (10).

9. Assembly according to one of the preceding claims in which the contact branch (18) has a thickness less than the distance between two adjacent sealing sectors.

10. Method (70) for detecting the presence of a stage 1 sealing plate of a low pressure turbine, said method comprising the steps of: - positioning (71) of a detection tool comprising: - a frame (10) comprising: • an upstream face (13); • a downstream face comprising a bearing surface (11); - a guide duct (15) extending from the upstream wall (13) towards the downstream and passing through the frame to the downstream face; - a job including: • a pin body (16) extending between an upstream portion (16a) and a downstream portion (16b) and sliding in the guide duct (15) and • a contact branch (17) extending from the downstream portion (16b) of the rod body to a contact end (18), - so that when the bearing surface (11) is in contact with an upstream periphery of a low-pressure turbine casing, the contact end (18) is downstream of an inter-sector sealing opening of stage 1 of a low-pressure turbine; - a gauge (19) integral in translation with the gauge body (16); - the positioning being carried out so as to place the support face (11) in radial and axial support on the upstream periphery of a low pressure turbine casing; - detection (72) of the position of the gauge, the gauge (19) being movable between: • a first position corresponding to the presence of a sealing plate (P) and in which the contact end (18) is supported on the sealing plate (P); • a second position corresponding to the absence of a sealing plate (P); - each position of the gauge (19) corresponding to an axially different position of the gauge body (16).

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