Removable turbomachine vent hole bushing and associated deposit removal method

Abstract

Removable sleeve for a turbomachine ventilation hole and associated method for removing deposits The invention relates to a turbomachine part (1) comprising a ventilation hole (5) in which is engaged a removable sleeve (9) which comprises a tubular body (10) open at its ends (13, 14), the side wall (11) of which completely covers the wall (6) of the hole, and a peripheral collar (15) extending radially on one side (18) of the part beyond the hole. A second similar removable sleeve can be engaged in the opposite direction in the inner duct (12) of the first sleeve, its side wall completely covering the side wall of the tubular body of the first sleeve and its peripheral collar extending radially on the other side (19) of the part. To clean the deposits (20), it is sufficient to replace the first or second removable sleeve with a clean sleeve. Figure to be published with the abstract: Figure 4

Description

Title of the invention: Removable turbomachine ventilation hole bushing and associated deposit removal method TECHNICAL FIELD OF THE INVENTION

[0001] The present invention relates to a removable sleeve intended to equip a ventilation hole of a turbomachine part. More generally, it relates to turbomachine parts which comprise ventilation holes which can be equipped with such a removable sleeve.

[0002] The present invention further relates to a method for removing coking deposits from the ventilation holes of turbomachine parts by means of such removable sleeves.

[0003] The invention finds applications in the field of aircraft turbomachines and their maintenance. TECHNOLOGICAL BACKGROUND OF THE INVENTION

[0004] In aircraft turbomachines, it is customary to send cooling air, taken from the upstream part of the turbomachine, generally at the level of the compressors, into the deep parts of the engine to achieve ventilation cooling.

[0005] For this purpose, the cooling air must circulate throughout the entire engine and its various cavities. Ventilation holes are provided for this purpose in several parts of the turbomachine, for example in the tapered parts of the turbine shafts or in the stator parts, to allow the cooling air to pass through them.

[0006] However, when it circulates inside the engine, the cooling air becomes loaded with various pollutants, particularly oil, as it passes near the bearings and other lubricated devices. Although present in small quantities, this oil gradually deposits on the downstream parts and ends up forming a deposit called a coking layer.

[0007] While this deposit is acceptable on most engine parts, it becomes particularly troublesome when it occurs at the ventilation holes. In fact, it gradually blocks the ventilation holes until it eventually obstructs them completely. The air passage section is thus gradually reduced, which limits the flow of cooling air and causes overheating of the engine parts.

[0008] However, this deposit is very hard and particularly difficult to remove. It is impossible to remove it without completely dismantling the part on which it is located. In addition, special and particularly lengthy cleaning is necessary to remove the layer of coking and unclogging ventilation holes, which significantly increases maintenance and part downtime.

[0009] Furthermore, since the ventilation holes are located in deep parts of the engine which are not visible in the assembled state, monitoring of their obstruction cannot be done by endoscopy and their unblocking cannot therefore be planned.

[0010] The discovery of a coking deposit to be removed is therefore an unforeseen event, which most often occurs during disassembly for another repair. It is then necessary to completely remove the coked part, then send it for a long period to a workshop capable of carrying out the appropriate cleaning. These unforeseen operations and the resulting unplanned immobilization of the part, often for several months, disrupt maintenance schedules and those of the airlines and generate great dissatisfaction on both sides. Summary of the invention

[0011] The invention aims to solve these problems by proposing a device and a method which make it possible to easily and quickly remove coking deposits from the ventilation holes of a turbomachine part, without having to dismantle this part.

[0012] For this, a first aspect of the invention teaches an aircraft turbomachine part comprising a wall in which at least one through ventilation hole delimited by a wall is provided.

[0013] This part further comprises a first removable socket, engaged in the ventilation hole and comprising: • a tubular body, which comprises a side wall completely covering the wall of the ventilation hole and delimiting an internal through conduit, open at a first end which opens on a first side of the wall of the room and at a second end which opens on a second side of the wall of the room; • a peripheral collar, which extends from the first side of the wall of the part and radially extends the tubular body beyond the ventilation hole.

[0014] Thus, when polluted cooling air circulates, the coking layer is deposited on the first removable sleeve, in particular in its tubular body, and not on the wall of the ventilation hole which is entirely covered and protected by the side wall of the tubular body of the sleeve.

[0015] Since this socket is removable, to remove this deposit, it is sufficient to remove the soiled socket from the ventilation hole by working from the side of its peripheral collar, then replace it with a clean socket without deposit. This removal operation and replacement of the removable bushing can be done very quickly and easily during a maintenance visit, without the need to disassemble the turbomachine part containing the holes. In addition, only removable bushings containing deposit will be replaced.

[0016] Once removed, the soiled bushings are simply disposed of, if they have been designed as a consumable product, or can be cleaned if they are reusable. But in this case, cleaning can advantageously be done independently of engine maintenance and without immobilizing the turbomachine part.

[0017] Such a removable sleeve can advantageously be installed without modification of the ventilation holes of the part, if the diameter of these holes is sufficient to guarantee a satisfactory flow of cooling air despite the reduction in diameter due to the presence of the removable sleeve. Otherwise, it is sufficient for the design to provide for enlarging the ventilation holes in which removable sleeves will be engaged.

[0018] The peripheral collar makes it possible to axially lock the removable bushing in the ventilation hole. It is placed on the side of the part from which the cooling air comes in the case of a unidirectional air flow (generally on the upstream side). It thus prevents the removable bushing from being carried away by the cooling air flow, by preventing its passage through the ventilation hole, which prevents the formation of potentially dangerous debris moving in the engine.

[0019] Furthermore, this collar can advantageously constitute a warning stop which, during assembly, allows the operator to ensure that he has pushed the first removable sleeve sufficiently into the ventilation hole to guarantee complete coverage of the wall of the hole by the side wall of the tubular body of the sleeve.

[0020] In the case of a bidirectional air flow, that is to say one likely to come alternately from both sides of the room, the second variant of the invention described below will preferably be used.

[0021] Similarly, this second variant will preferably be used in the case of a unidirectional cooling air flow, but coming from a side of the part not easily accessible to the operator without disassembly.

[0022] Advantageously, the first removable sleeve may further comprise a cylindrical shoulder, located on the first side of the wall, between the peripheral collar and the wall of the part and which bears against said wall of the part.

[0023] This shoulder facilitates the removal of the removable socket, by making it easier to insert a disassembly tool (for example a flat screwdriver blade, a plastic shim) between the peripheral collar of the socket and the wall of the part. or the jaws of pliers), allowing the operator to exert a withdrawal force on the socket.

[0024] In this case, it is the cylindrical shoulder which, by coming to bear against the wall of the part, will serve as a warning stop for the operator in place of the peripheral collar.

[0025] Advantageously, the tubular body may comprise a projecting portion which protrudes out of the ventilation hole on the second side of the wall.

[0026] Such a protruding portion can advantageously be used to push on the removable sleeve from the second side of the wall and towards the first side in order to facilitate its removal.

[0027] Advantageously, this projecting part may include notches.

[0028] These notches are simple shapes to machine, which can advantageously be used to slide the end of a counter-torque tool (the blade of a screwdriver or the jaws of pliers for example) into them, in order to oppose the rotation of the first removable socket during the screwing or unscrewing of a second removable socket in its internal conduit.

[0029] Advantageously, the first removable sleeve is mounted with a tight fit in the ventilation hole. The first removable sleeve is thus held in position in the ventilation hole without the need to modify the latter, no machining of the wall of the hole being necessary. In order to be able to be easily force-fitted into the ventilation hole, the first removable sleeve is preferably made of a less rigid material than the wall of the ventilation hole, which is conventionally made of steel. It may thus, for example, be made of a plastic material resistant to a temperature of the order of 200 to 300°C (temperature prevailing in the deep parts of an engine in operation) or of a ductile metal, copper or bronze for example, or of a ductile metal alloy preferably comprising the same base metal as the wall of the ventilation hole in order to avoid galvanic corrosion phenomena.

[0030] According to a second advantageous variant, the turbomachine part may further comprise a second removable sleeve engaged in the inner duct of the first removable sleeve, this second removable sleeve being removably fixed to the first removable sleeve and comprising: • a tubular body, which comprises a side wall completely covering the side wall of the tubular body of the first removable socket and delimiting an internal through conduit, open at a first end which opens on the second side of the wall of the room and at a second end which opens on the first side of the wall of the room; • a peripheral collar, which extends from the second side of the wall of the part and radially extends the tubular body beyond the side wall of the tubular body of the first removable sleeve and the ventilation hole.

[0031] This variant can advantageously be used in the case of a bidirectional air flow or a unidirectional air flow but coming from an inaccessible side of the room.

[0032] Regardless of the direction of circulation of the cooling air flow, the two removable bushings are retained axially and cannot be carried away or escape from the ventilation hole. Indeed, regardless of the side from which the air arrives, one of the bushings is retained by its peripheral collar and the other is held axially by its attachment to the first.

[0033] With this second variant, the coking layer is deposited in the tubular body of the second removable sleeve and not on the side wall of the tubular body of the first sleeve which is entirely covered by the side wall of the tubular body of the second sleeve, nor on the wall of the ventilation hole which is entirely covered by the side wall of the tubular body of the first sleeve.

[0034] Since the second sleeve is removable, to remove this deposit, it is sufficient to remove the second soiled removable sleeve from the first removable sleeve, by releasing it from its removable attachment with the first sleeve and removing it from the side of its peripheral collar. It is then replaced by a second clean removable sleeve without deposit.

[0035] This operation of removing and replacing the second coked removable bushings can be done very quickly and very easily during a maintenance visit, without needing to dismantle the turbomachine part comprising the holes, nor the first removable bushings, nor even the second bushings not comprising a deposit.

[0036] Once removed, the soiled second casings can be disposed of or cleaned for reuse.

[0037] Advantageously, these removal and replacement operations are carried out on the opposite side to those of the first variant. This second variant therefore advantageously resolves the problem of inaccessibility occurring with the first variant in the case of a unidirectional air flow coming from the inaccessible side of the room.

[0038] As with the previous variant, the ventilation holes of the part can be kept without modification if their diameter is sufficient to ensure satisfactory cooling despite the reduction in diameter due to the presence of the two removable bushings. Otherwise, the diameter of the ventilation holes will be provided larger accordingly in the design.

[0039] Advantageously according to this second variant, the second removable socket can be fixed in a removable manner to the first removable socket by screwing its wall lateral to the side wall of the first removable sleeve or by a quarter-turn fixing device. The second removable sleeve is thus perfectly retained axially in the first removable sleeve regardless of the direction of the cooling air flow. However, it remains removable and can be easily and quickly put in place or removed.

[0040] Advantageously according to this second variant, the peripheral collar of the second removable sleeve comprises gripping reliefs, preferably grooves. Since the assembly and disassembly of the second removable sleeve are most often manual, these reliefs allow the operator to grip the sleeve more effectively and to more easily exert the force necessary for its assembly or disassembly, by screwing / unscrewing for example.

[0041] Advantageously according to this second variant, the peripheral collar of the second removable sleeve comprises on the underside at least two returns, distributed in a regular radial arrangement and which come to bear against the wall of the part.

[0042] By pressing against the wall, these returns provide greater mechanical resistance to the peripheral collar. In addition, they constitute a stop which, during assembly, allows the operator to ensure that he has pushed the second removable sleeve sufficiently into the internal conduit of the first removable sleeve so that the covering of the side wall of the tubular body of the first removable sleeve is complete.

[0043] Furthermore, since these returns are distributed in a regular radial arrangement, they prevent the second removable sleeve from being skewed when it is pushed in.

[0044] A distribution according to a regular radial arrangement of the returns means that they are positioned on the same circle with a constant angular gap between two consecutive returns, thus corresponding to 180° for two returns, 120° for three returns, etc.

[0045] Finally, since these returns are not joined, there remain free spaces between them which allow the operator to easily access the second end of the first removable socket and more particularly the notches of its projecting part if it has any.

[0046] A second aspect of the invention relates to a method for cleaning the ventilation hole of an aircraft turbomachine part according to the first variant described above, characterized in that the first removable sleeve is removed from the ventilation hole and replaced by a first clean removable sleeve.

[0047] A third aspect of the invention relates to a method for cleaning the ventilation hole of an aircraft turbomachine part according to the second variant described above, characterized in that the second removable sleeve is removed from the duct inside the first removable socket and replace it with a second clean removable socket.

[0048] These processes make it possible to get rid of deposits very simply and very quickly, without needing to dismantle the turbomachine part.

[0049] 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

[0050] The figures are presented for information purposes only and in no way limit the invention.

[0051] [Fig. 1] is a partial perspective view of a turbomachine turbine shaft having ventilation holes.

[0052] [Fig.2] is a schematic perspective side view of an example of a removable socket according to the first variant of the invention.

[0053] [Fig.3] is a schematic perspective view of a portion of the turbine shaft of [Fig.l] equipped with two removable bushings according to [Fig.2].

[0054] [Fig.4] is a schematic sectional view at the level of a ventilation hole of a portion of the turbine shaft of [Fig.l] equipped with a removable sleeve according to [Fig.2],

[0055] [Fig.5] and [Fig.6] are schematic perspective views, respectively from the side and from below, of an example of a first removable socket according to the second variant of the invention.

[0056] [Fig.7] and [Fig.8] are schematic perspective views, respectively from above and from the side, of an example of a second removable socket according to the second variant of the invention.

[0057] [Fig.9] and [Fig.10] are schematic views, respectively from the side and in section at the level of a ventilation hole, of a portion of the turbine shaft of [Fig.1] equipped with a first and a second removable sleeve according to the second variant of the invention. DETAILED DESCRIPTION

[0058] Unless otherwise specified, the same element appearing in different figures has a single reference.

[0059] In the present application, the terms "upstream" and "downstream" are defined with respect to the normal flow direction of gases (from upstream to downstream) through a turbomachine.

[0060] In [Fig.l], an example of part 1 of an aircraft turbomachine concerned by the invention is shown.

[0061] This is a turbine shaft, of which only a part has been shown and which comprises an axis 2 and a conical end portion 3 whose wall 4 is pierced with a plurality of 5 through ventilation holes, regularly distributed in a circle around the axis 2. These holes 5 are each delimited by a wall 6.

[0062] The conical end portion 3 is extended radially by a flat peripheral flange 7, allowing assembly to another part of the turbomachine, a trunnion cone for example. The peripheral flange 7 comprises for this purpose a plurality of through assembly holes 8, arranged circularly and regularly distributed, intended to be crossed by fixing elements such as bolts for example.

[0063] As shown in [Fig. 3], the ventilation holes 5 of the turbine shaft can advantageously be equipped with a first removable sleeve 9 according to the invention. Advantageously, the ventilation holes of other parts of the engine can also be equipped with this type of removable sleeves 9.

[0064] This first removable socket 9 can be used alone, according to a first variant of the invention shown in Figures 2 to 4.

[0065] It comprises a tubular body 10 with a round section, comprising a side wall 11 which delimits an internal conduit 12 passing through, open at its first end 13 and at its second end 14.

[0066] It also comprises a peripheral collar 15, which radially extends the tubular body 10 outwards, preferably at its first end 13.

[0067] In the example shown, the first removable sleeve 9 also comprises a cylindrical shoulder 16 located under the peripheral collar 15 (on the underside thereof). This cylindrical shoulder 16 originates from the outer face 17 of the side wall 11 of the tubular body 10 and extends radially outwards, thus constituting an enlargement of the outer diameter of the side wall 11 which is thicker at this level.

[0068] In use, the first removable socket 9 is engaged in the ventilation hole 5 as shown in Figures 3 and 4.

[0069] Its tubular body 10 passes through the ventilation hole 5, in which it is preferably mounted in a tight fit, its first end 13 opening on a first side 18 and its second end 14 on a second side 19 of the wall 4 of the part 1. Its side wall 11 thus completely covers the wall 6 of the ventilation hole 5 and protects it from any dirt. In use, any deposits 20 form on the inner face 21 of the side wall 11.

[0070] The peripheral collar 15 is not engaged in the ventilation hole 5. It is located on the first side 18 of the wall 4 and protrudes radially beyond the diameter of the ventilation hole 5. It thus constitutes an axial retainer for the first removable sleeve 9 and prevents it from passing through the ventilation hole 5. It is placed on the side of the wall 4 through which the air flow arrives if it is unidirectional.

[0071] In the example shown, the cylindrical shoulder 16 bears against the wall 4 on the first side 18 thereof. It thus maintains a slight gap between the wall 4 and the peripheral collar 15 allowing the tip of a tool to slide therein to facilitate the removal of the first removable sleeve 9.

[0072] The excess thickness relative to the wall 4, constituted by the peripheral collar 15 and the cylindrical shoulder 16, is exaggerated in the figures for better understanding. It is preferably of a height less than or equal to 1 mm to limit disturbances to the air flow in the turbomachine.

[0073] The second end 14 of the tubular body 10 is flush with the wall 4 or has a projecting part 22 which protrudes slightly from the second side 19 of the wall 4. In the same way, this projecting part 22 is preferably of a height less than or equal to 1 mm.

[0074] When the first removable socket 9 is used according to the second variant of the invention shown in FIGS. 5 to 10, this projecting part 22 preferably comprises notches 23, for example with a flat or rounded bottom 24.

[0075] In this second variant, the first removable sleeve 9 is combined with a second removable sleeve 25, which also comprises a tubular body 26 with a round section, the side wall 27 of which delimits an internal conduit 28 passing through, open at its first end 29 and at its second end 30, as well as a peripheral collar 31 which radially extends its tubular body 26 towards the outside, preferably at its first end 29.

[0076] In the example shown, this peripheral collar 31 has at its edge 32 gripping reliefs 33, for example grooves 34, which improve its grip by the operator and facilitate its actuation.

[0077] It also comprises two diametrically opposed returns 35, which originate on the underside of the peripheral collar 31 and extend towards the second end 30.

[0078] In use and as shown in Figures 9 and 10, the first removable sleeve 9 is engaged in the ventilation hole 5 as previously described and the second removable sleeve 25 is engaged in the opposite direction in the first removable sleeve 9.

[0079] The tubular body 26 of the second removable sleeve 25 passes through the inner conduit 12 of the first removable sleeve 9, its first end 29 opening out on the second side 19 and its second end 30 on the first side 18 of the wall 4. Its side wall 27 then completely covers the side wall 11 of the tubular body 10 of the first removable sleeve 9 and protects it from any deposits which form on the inner face 36 of the side wall 27.

[0080] The second removable sleeve 25 is removably attached to the first removable sleeve 9. In the example shown, it has for this purpose a thread 37 on the outer face 38 of its side wall 27 which cooperates and engages with a thread 39 of the inner face 21 of the side wall 11 of the first sleeve 9.

[0081] This screw fixing can be replaced by any other similar fixing, for example a quarter-turn or bayonet fixing with slots and lugs.

[0082] The peripheral collar 31 of the second removable sleeve 25 is located on the second side 19 of the wall 4 and protrudes radially beyond the diameter of the tubular body 10 of the first removable sleeve 9 and the ventilation hole 5.

[0083] However, the collar 31 remains at a distance from the wall 4, because the returns 35 abut against the wall 4. The notches 23 of the projecting part 22 of the first removable sleeve 9 are thus accessible, under the collar 31 and between the returns 35, as visible in [Fig.9]. The operator can slide the tip of a counter-torque tool there, to block the rotation of the first removable sleeve 9, when he screws or unscrews the second removable sleeve 25.

[0084] For better understanding, the excess thickness formed by the peripheral collar 31 and the returns 35 relative to the wall 4 has been exaggerated in the figures. It is preferably of a height less than or equal to 1 mm to limit disturbances to the air flow in the turbomachine.

Claims

Claims

1. Part (1) of an aircraft turbomachine comprising a wall (4) in which is provided at least one ventilation hole (5) passing through, delimited by a wall (6), part (1) characterized in that it further comprises a first removable sleeve (9), engaged in the ventilation hole (5) and comprising: - a tubular body (10), which comprises a side wall (11) entirely covering the wall (6) of the ventilation hole (5) and delimiting an internal conduit (12) passing through, open at a first end (13) which opens on a first side (18) of the wall (4) of the part (1) and a second end (14) which opens on a second side (19) of the wall (4) of the part (1); - a peripheral collar (15), which extends from the first side (18) of the wall (4) of the part (1) and radially extends the tubular body (10) beyond the ventilation hole (5).

2. Part (1) according to claim 1 characterized in that the first removable sleeve (9) further comprises a cylindrical shoulder (16), located on said first side (18), between the peripheral collar (15) and the wall (4) of the part (1) and which bears against said wall (4) of the part (1).

3. Part (1) according to one of the preceding claims, characterized in that the tubular body (10) comprises a projecting part (22) which protrudes out of the ventilation hole (5) on the second side (19) of the wall (4).

4. Part (1) according to one of the preceding claims, characterized in that the first removable sleeve (9) is mounted in a tight fit in the ventilation hole (5).

5. Part (1) according to one of the preceding claims, characterized in that it further comprises a second removable sleeve (25) engaged in the inner conduit (12) of the first removable sleeve (9), this second removable sleeve (25) being removably fixed to the first removable sleeve (9) and comprising: - a tubular body (26), which comprises a side wall (27) entirely covering the side wall (11) of the tubular body (10) of the first removable sleeve (9) and delimiting a through inner conduit (28), open at a first end (29) which opens out on the second side (19) of the wall (4) of the part (1) and a second end (30) which opens out on the first side (18) of the wall (4) of the part (1); - a peripheral collar (31), which extends on the second side (19) of the wall (4) of the part (1) and radially extends the tubular body (26) beyond the side wall (11) of the tubular body (10) of the first removable sleeve (9) and the ventilation hole (5).

6. Part (1) according to claim 5 when dependent on claim 3 characterized in that the projecting part (22) of the tubular body (10) of the first removable sleeve (9) comprises notches (23).

7. Part (1) according to claim 5 or 6 characterized in that the second removable sleeve (25) is removably fixed to the first removable sleeve (9) by screwing its side wall (27) to the side wall (11) of the first removable sleeve (9) or by a quarter-turn fixing device.

8. Part (1) according to one of claims 5 to 7 characterized in that the peripheral collar (31) of the second removable sleeve (25) comprises gripping reliefs (33).

9. Part (1) according to one of claims 5 to 8, characterized in that the peripheral collar (31) of the second removable sleeve (25) comprises on the underside at least two returns (35), distributed in a regular radial arrangement and which come to bear against the wall (4) of the part (1).

10. Method for cleaning the ventilation hole (5) of a part (1) of an aircraft turbomachine according to one of claims 1 to 4, characterized in that the first removable sleeve (9) is removed from the ventilation hole (5) and replaced by a clean first removable sleeve (9).

11. Method for cleaning the ventilation hole (5) of a part (1) of an aircraft turbomachine according to one of claims 5 to 9, characterized in that the second removable sleeve (25) is removed from the inner duct (12) of the first removable sleeve (9) and replaced by a second clean removable sleeve (25).

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