EP3807500A1

EP3807500A1 - Holding system for the dismantling of a blade wheel

Info

Publication number: EP3807500A1
Application number: EP19735372.5A
Authority: EP
Inventors: Nicolas Daniel DELAPORTE; Alain Dominique Gendraud; Emmanuel Bernard Marie CHARRIER
Original assignee: Safran Aircraft Engines SAS
Current assignee: Safran Aircraft Engines SAS
Priority date: 2018-06-12
Filing date: 2019-06-06
Publication date: 2021-04-21
Anticipated expiration: 2039-06-06
Also published as: JP2021527180A; JP7485618B2; CA3102895A1; WO2019239036A1; FR3082232A1; US11441431B2; EP3807500B1; RU2765596C1; CN112313396A; CN112313396B; BR112020025238A2; FR3082232B1; US20210254481A1

Abstract

The present invention relates to a holding system for the dismantling of a blade wheel, the blade wheel comprising: - a disc (2), - a plurality of blades configured to be mounted circumferentially around the disc (2), the plurality of blades defining a plurality of inter-blade spaces, the inter-blade spaces each being circumferentially defined between two adjacent blades (3a, 3b) of the plurality of blades, the holding system comprising a plurality of inserts (21), each of the inserts (21) being configured to be inserted in each of the inter-blade spaces in a holding position so as to hold the relative position of the blades when the plurality of blades is dismantled from the disc (2).

Description

Support system for removing a paddle wheel

TECHNICAL AREA

The present disclosure relates to a holding system for disassembling an impeller and a method of disassembling an impeller.

TECHNOLOGICAL BACKGROUND

It is known from the prior art, in particular from document FR 3 008 448, a turbine rotor comprising a mobile impeller 1, that is to say configured to be driven in rotation about the axis of the rotor, represented in FIG. 1, forming a crown, and which comprises a disc 2 around which are circumferentially mounted a set of blades 3. It is also known to maintain the blades 3 axially by means of a retaining ring 17. In operation , the retaining ring 17 is subject to faster wear than the disc 2. It is therefore to be replaced more regularly. However, to reach the retaining ring 17, and to be able to replace it, it is necessary to remove the impellers arranged downstream of the impeller which comprises the used retaining ring. However, to remove the blades of the different moving vane wheels arranged downstream, it is necessary to remove the blades from the discs one by one, then, once the retaining ring has been replaced, reassemble the blades on the wheel discs one by one with movable blades. Such an operation is time consuming and represents a significant cost

PRESENTATION

The present presentation aims to solve all or part of the drawbacks mentioned above.

To this end, the present disclosure relates to a holding system for the disassembly of an impeller, the impeller comprising:

- a disk,

- a plurality of blades configured to be mounted circumferentially around the disc, the plurality of blades defining a plurality of inter-blade spaces, the spaces inter-blades each being defined circumferentially between two adjacent blades of the plurality of blades,

the holding system comprising a plurality of inserts, each of the inserts being configured to be inserted in each of the inter ^¬ blade spaces in a holding position so as to maintain the relative position of the blades when the plurality of blades is removed from the disc .

Called axis of the impeller, symmetry tax (or quasi-symmetry) thereof. This axis corresponds to the impeller rotation tax. The axial direction corresponds to the direction of the impeller of the impeller and a radial direction is a direction perpendicular to the axis of the impeller and intersecting this axis. Likewise, an axial plane is a plane containing the impeller of the impeller and a radial plane is a plane perpendicular to this axis.

A circumference is understood as a circle belonging to a radial plane and the center of which belongs to the axis of the impeller. A circumferential direction is a direction along a circumference.

Unless specified otherwise, the inner / inner and outer / outer adjectives are used with reference to a radial direction so that the inner part of an element is, in a radial direction, closer to the axis of the wheel. paddle as the outer part of the same element.

Thanks to these provisions, it is possible to access the retaining ring by dismantling the disc of a given movable impeller, without having to disassemble the movable impellers arranged downstream. Thus, a saving of time is obtained to access a damaged retaining ring carried by this given mobile impeller. Indeed, the relative position of the blades being maintained, it is possible to disassemble and reassemble all of the blades on the disc at once, without having to disassemble or reassemble them one by one. Thus, the disassembly and reassembly of the impeller is faster and more efficient. In addition, the inserts taking up the forces exerted on the disc, the disc is more easily removable.

The holding position is at a determined height of the inter-blade space in the radial direction. When an insert is in the holding position, the center of the insert in the radial direction is at the determined height.

For example, the holding position of the inserts is preferably as close as possible to the disc, in order to best maintain the blades.

In some embodiments, the impeller further includes a retaining ring configured to axially hold the blades on the disc.

In some embodiments, each blade of the plurality of blades comprises a foot, a blade and a head, arranged in this order in a longitudinal direction of the blade. When the blade is mounted on the disc, the longitudinal direction of the blade corresponds to the radial direction.

In some embodiments, the holding position of the inserts is at an internal portion of the inter-blade space, defined between the blade root and the center of the inter-blade space according to a radial direction.

It is understood that at least part of each insert has a shape corresponding to the inter-blade space, defined between two adjacent blades. In addition, at least a portion of the inserts follows the shape of a portion of the blades of two adjacent blades.

It is understood that, in the holding position, each insert is disposed against, and preferably directly against, each of the adjacent blades defining the inter-blade space.

In certain embodiments, each of the inserts comprises at least one portion of an aluminum-based alloy, and / or a polymer having a shore A hardness of between 75 and 100.

By "based on" means an alloy comprising at least 50% by mass of aluminum.

For example, the inserts could comprise a portion comprising an aluminum-based alloy covered with a polymer.

For example, the polymer is a resin. It is understood that the at least one portion comprising aluminum, or a polymer having a shore A hardness of between 75 and 100 is a portion in contact with a blade.

For example, the at least one portion consists of an aluminum-based alloy, and / or of a polymer having a shore A hardness of between 75 and 100.

It is understood that the material forming the blade is less tender than the aluminum-based alloy and / or the polymer having a shore A hardness of between 75 and 100.

Thus, when the inserts are installed in their holding position, the risk of damaging the blades, which are formed from a material harder than the material of the portions of the inserts in contact with the blades, is more limited.

In some embodiments, the inserts have a thickness in a radial direction greater than or equal to 10% of the height of a blade of a blade in the radial direction.

The height of a blade of a blade means the greatest distance between a platform of the blade root and a platform of the blade head.

Thus, sufficient contact surfaces with the blades are guaranteed and maintaining the position of the blades relative to each other is more effective.

For example, the thickness is approximately 10 mm, for a blade height of approximately 100 mm.

In some embodiments, the insert comprises a first part and a second part. The first part is the part of the insert intended to be inserted in the inter-blade space. The second part is used, for example, for mounting the insert. The greatest length in an axial direction of the first part is between 10 mm and 20 mm, that is to say represents between 70% and 100% of the length of the blade of the blade in the axial direction.

In some embodiments, the holding system comprises a gripping portion configured to be mounted on an insert of the plurality of inserts, the gripping portion being configured to allow the gripping of the insert and facilitate assembly of the insert in an inter-blade space. Thus, the manipulation of the inserts during their insertion into the inter-blade spaces is facilitated.

For example, the gripping portion can allow the inserts to be mounted directly at their holding position, by a movement which follows the shape of the insert. Indeed, the gripping portion can form a lever arm which allows to be able to exert sufficient force on the insert to insert it directly into the holding position.

In some embodiments, the holding system comprises a device for positioning the plurality of inserts, each insert of the plurality of inserts being configured to be attached to the positioning device so as to hold in position the inserts, that is to say so that the inserts are arranged in the holding position.

Thus, the inserts are substantially aligned in a circumferential direction, which allows to balance the forces exerted on the blades, and thus more effectively maintain the position of the blades relative to each other, and will facilitate the disassembly of the disk.

For example, the positioning device allows slightly different insert holding positions in the radial direction, so as to compensate for the dimensional tolerances / dispersions of the blades.

By "substantially" or "slightly" is meant that the actual height in the radial direction of the inserts in their holding position differs by at most 5% from the determined height.

The positioning device allows the radial locking of the inserts which ensures the integrity of the assembly comprising the blades and the inserts, especially when the disc is disassembled.

In some embodiments, the positioning device comprises a positioning ring, the positioning ring comprising fixing elements to allow the fixing of the inserts on the positioning ring. Thus, the inserts are held in their holding position, which makes it possible to more effectively maintain the relative position of the blades.

It is understood that the positioning device is annular.

In some embodiments, the fastening elements allow the fastening of the inserts on the positioning ring.

In some embodiments, the fastening elements of the positioning device are intended to be arranged opposite the inserts when the inserts are in the holding position, to allow the fastening of the inserts on the positioning device.

For example, the fastening elements comprise oblong openings each opening towards an inter-blade space. For example, the oblong slots extend in the radial direction so as to allow a slightly different positioning of the inserts relative to each other in the radial direction.

For example, the inserts each include a blind hole extending in the axial direction. The blind hole is intended to come opposite the oblong lumen when the insert is in the holding position.

For example, a fixing member makes it possible to fix the insert on the positioning ring, by cooperating with the blind hole.

For example, the blind hole is bored and the fixing member is threaded.

For example, the fasteners are threaded and are configured to cooperate with the bored blind holes present in each of the inserts. In addition, the fixing members are configured to hold the inserts against the positioning ring, for example by means of a stop element, such as a screw head.

In some embodiments, the inserts each include a first member and a second member, the first and second members being configured to be arranged in an inter-blade space, the first member being disposed against a first blade, and the second member being disposed against a second blade circumferentially adjacent to the first blade; and a clamp, configured to be inserted between the first and second organs so as to maintain the insert between the first and second blades.

For example, the clamping piece is configured to be inserted between the first and second members in the axial direction.

Thus, the mounting of the inserts can be performed axially especially when the radial mounting is difficult to achieve in certain circumstances. This embodiment of the inserts also makes it possible to adapt the clamping to each inter-blade space, as a function of the insertion of the clamping piece.

For example, the holding system comprises a stop disc, allowing the positioning of the inserts.

In certain embodiments, at least one of the first and second members comprises a guide surface, configured to guide the clamping piece during its insertion between the first and second members and to avoid the radial displacement of the clamping piece .

In some embodiments, the clamping piece comprises a stopper configured to come into contact with the first and second members when the clamping piece is mounted between the first and second members.

In some embodiments, the clamping piece has a wedge shape, bevel, conical or rectangular.

The present disclosure also relates to a method for dismantling an impeller comprising a disc and a plurality of blades circumferentially mounted around the disc, the plurality of blades defining a plurality of inter-blade spaces. , the inter-blade spaces each being defined circumferentially between two adjacent blades of the plurality of blades, the disassembly process comprising the following steps:

A. inserting a plurality of inserts of a holding system into the inter-blade spaces in a holding position so that the relative position of the blades is maintained;

B. remove the disc.

Thanks to these provisions, it is possible to access the retaining ring by dismantling the disc of a mobile impeller without having to disassemble the moving vane wheels arranged downstream. Thus, a saving of time is obtained to access a damaged retaining ring carried by this given mobile impeller. Indeed, the relative position of the blades being maintained, it is possible to disassemble and reassemble all of the blades on the disc at once, without having to disassemble or reassemble them one by one. Thus, the disassembly and reassembly of the impeller is faster and more efficient. In addition, the inserts taking up the forces exerted on the disc, the disc is more easily removable.

In certain embodiments, the method further comprises the following steps:

- replace a retaining ring configured to maintain the position of the blades in an axial direction,

- reengage the blades on the disc,

- remove the paddle wheel holding system.

In certain embodiments, during step A:

the inserts are inserted at a radially external portion of the inter-blade spaces, and

- The inserts are moved in a radial direction, radially inward, until reaching the holding position.

Thus, it is possible to adjust the position of the inserts as a function of the force which it is desired to apply to the blades and as a function of the dimensional tolerances / dispersions of the blades.

Alternatively, the inserts are inserted directly at their holding position, thanks to a gripping portion, by a movement which follows the shape of the insert. Indeed, the gripping portion can form a lever arm which allows to be able to exert sufficient force on the insert to insert it directly into the holding position.

In certain embodiments, the inserts each comprise a first member, a second member and a clamping piece, during step A:

- the first member has an insert, in an inter-blade space, against a first blade at the level of the holding position, the second member of the insert is placed, in the inter-blade space, against a second blade, adjacent to the first blade, so that the second member is arranged circumferentially opposite the first member,

- The clamping piece is inserted between the first and second members so as to keep the insert in the holding position.

Thus, the mounting of the inserts can be carried out axially if the radial mounting is difficult to achieve in certain circumstances.

For example, to position and maintain the inserts in the holding position, one can have a positioning device at the holding position of the inserts.

For example, the positioning device comprises a positioning ring, and the positioning ring is positioned in such a way that the fastening elements, for example oblong slots, are located at the position for holding the inserts. Thus, when the inserts are mounted, and face the fixing elements, the inserts can be fixed to the positioning ring.

For example, the inserts are fixed to the positioning ring thanks to the fixing elements.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention and its advantages will be better understood on reading the detailed description given below of different embodiments of the invention given by way of non-limiting examples. This description refers to the pages of attached figures, on which:

- Figure 1 shows a paddle wheel;

- Figure 2 shows a sectional view of the impeller according to the plane II-II of Figure 1;

- Figure 3 shows a schematic portion view of an impeller in which inserts are inserted in the inter-blade spaces;

- Figure 4 shows an insert according to a first embodiment; - Figure 5 shows an insert according to the first embodiment, mounted on the impeller and fixed to a positioning device;

- Figure 6 shows an insert according to the first embodiment on which is mounted a gripping portion;

- Figure 7 shows a portion of the impeller, on which is mounted a holding system according to the first embodiment;

- Figure 8 shows a portion of the impeller, on which is mounted an insert according to the second embodiment;

- Figure 9 shows a step of mounting an insert according to the first embodiment in an inter-blade space.

DETAILED DESCRIPTION

Figure 1 shows an impeller 1. For example, the impeller 1 is installed at the low pressure turbine of a turbomachine.

The impeller 1 comprises a disc 2 and a plurality of vanes 3. The plurality of vanes 3 is mounted on the disc 2 around its circumference.

Figure 2 is a section of the impeller 1 according to the plane II-II shown in Figure 1. The blade 3 shown in Figure 2 comprises a blade 5, a blade root 7 and a head d 'blade 9. The blade root 7 comprises a radially internal platform 11. The blade head 9 comprises a platform 13 radially external. The blade 5 extends radially between the platforms 11, 13. All the blades 3 of the plurality of blades are similar to the blade shown in FIG. 1. The blades 5 of the blades 3 each have a concave face and a convex face .

When mounted on the disc 2, the blades 3 extend in a radial direction DR and are spaced from each other so as to define inter-blade spaces 15, visible in Figure 1 for example. It is understood that an inter-blade space 15 is defined between two adjacent blades 3. The distance between two blades 5 of adjacent blades 3 is greater near the blade heads 9 than proximity of the blade roots 7. Thus, the distance between two blade blades decreases between the blade heads 9 and the blade feet 7.

The vanes 3 are mounted on the disc 2 in a nominal operating position.

Figures 1 and 2 also show a retaining ring 17, configured to axially block the vanes 3 on the disc 2.

Figure 3 shows a portion of an impeller 1 and a holding system 19 for disassembly of the impeller 1. The holding system 19 comprises a plurality of inserts 21. The inserts 21 are here inserted in each of the inter-blade spaces 15 so as to maintain the relative position of the blades 3 and to allow disassembly of the disc 1.

An insert according to the first embodiment is shown in Figures 4 and 5.

The insert 21 comprises a first part 23 and a second part 25. The first part 23 is configured to maintain the relative position of the blades 3. The first part 23 comprises a first contact surface 27, configured to come into contact of a blade 5a of a first blade 3a and follow the shape of the convex face of the blade 5a. Here, the first contact surface 27 therefore has a concave shape. In other words, the first contact surface 27 and the convex face of the blade 5a have complementary shapes.

The first part 23 further comprises a second contact surface 29, configured to come into contact with a blade 5b of a second blade 3b and match the shape of the concave face of the blade 5b. Here, the second contact surface 29 therefore has a convex shape. In other words, the second contact surface 29 and the concave face of the blade 5b have complementary shapes. The first and second blades 3a, 3b are adjacent in the circumferential direction of the impeller.

The convex face of the blade 5a and the concave face of the blade 5b face each other in the circumferential direction. The surfaces of the blades 5a, 5b of the first and second blades 3a, 3b define the inter-blade space 15. It is understood that the first part 23 of the insert 21 has a shape corresponding to a portion of the inter-blade space 15, when the blades 3 are in the nominal position. Thus, when the inserts 21 are mounted in the inter-blade spaces 15 at a holding position, the blades of the impeller are held together via the inserts, which releases the stresses applied by the blade roots 7 at the level of the disc cavities in which the blade roots are mounted and thus allows easy mounting or dismounting of the disc.

For example, at least the portions of the first part 23 of the insert 21 in contact with the blades 5a, 5b of the blades 3a, 3b, and preferably at least the first part 23 of the insert 21, comprise / comprises an aluminum-based alloy, and / or a polymer having a shore A hardness of between 75 and 100. For example, the polymer is a resin.

The dimension of the section of the first part 23 of the insert 21 along a plane normal to the radial direction DR is greater than the dimension along this plane of the inter-blade space 15 near the feet of blade 7. Thus, the insert 21, in the position for maintaining the relative position of the blades 3, is positioned in the inter-blade space 15 at a portion having substantially the same dimension as the dimension of the section of the insert 21 along a plane normal to the radial direction DR.

Generally, the inserts 21 are arranged at a first end portion of the inter-blade spaces 15, defined, for each inter-blade space, between the blade root 7 and the center of the space inter-blade 15 in the radial direction DR.

The inserts 21, and more particularly their first part 23, have a thickness e in the radial direction DR greater than or equal to 10% of the height h of the blade in the radial direction DR.

The holding position of each insert is at a determined height of the inter-blade space 15, or adjacent blades 5. When the insert 21 is in the holding position, the center of the insert according to the radial direction, that is to say a height of the insert corresponding to half its thickness e, is at the level of the determined height. Sometimes, because of the dimensional tolerances or dispersions of the blades, the height in the radial direction, corresponding to the holding position, is significantly different to the height determined for certain inserts. However, the difference between the actual height of the position for holding the inserts 21 and the determined height is less than or equal to 5% of the total height of the blade 5, or of the inter-blade space 15.

For example, the thickness e is approximately 10 mm, for a blade height of approximately 100 mm. For example, the greatest length along an axial direction DA of the first part 23 is 15 mm, that is to say between 70 and 100% of the length along the axial direction DA of the blade 5 of the blade 3.

The second part 25 of the insert 21 is connected to the first part of the insert 23. For example the first and second parts 23, 25 are formed together.

The second part 25 extends, here, in the extension of the first part 23 in the axial direction DA. The second part 25 provides a gripping means making it possible to engage or disengage the insert 21 from the inter-blade space 15. The second part 25 can also serve as a support for mounting the insert 21 on other elements.

For example, as shown in Figure 6, the holding system 19 may further comprise a gripping portion 31 of the inserts 21. The gripping portion 31 can be mounted on the second part 25. The gripping portion 31 allows to form a handle, long enough to allow a user to grip it easily. Thus, the gripping portion 31 makes it easier to handle the inserts 21 and their insertion in the inter-blade spaces 15. For example, the gripping portion 31 is removably mounted on the second part 25. In this way, the The user can use the same gripping portion 31 for mounting all of the inserts 21.

In addition, as shown in Figure 7, the holding system 19 may include a positioning device 33. The positioning device 33 comprises, in this embodiment, a positioning ring 35 configured to be positioned against the vanes 3, in a circumferential direction. The positioning ring 35 includes oblong slots 37 emerging towards the inter-blade space 15. The oblong slots 37 extend in a radial direction DR so as to allow a slightly different positioning of the inserts 21 relative to each other in the radial direction DR, so as to take account dimensional tolerances / dispersions.

For example, the second part 25 comprises a blind hole 38 bored extending in the axial direction DA. The blind hole 38 is intended to come opposite the oblong opening 37, when the insert 21 is in the holding position. A fixing member 39 makes it possible to fix the insert 21 on the positioning ring 35. For example, as shown, the fixing member 39 is a screw, configured to be inserted in the blind hole 38 bored. However, the insert 21 could be fixed to the positioning ring 35 by any other means. In this way, the inserts 21 are substantially aligned along the circumferential direction.

In order to position the inserts 21 at the same radial height in the inter-blade spaces according to another embodiment (not shown), an internal radial stop disc could be provided at a predetermined height, corresponding to the holding position of the inserts 21. The second part 25 of the inserts could then come into abutment against the internal disc. Once the plurality of inserts have been mounted, an external radial locking disc is positioned allowing the position of the inserts 21 to be maintained.

The method of removing the impeller 2 according to the first embodiment is described below.

First, the inserts 21 are inserted, one by one, in each of the inter-blade spaces 15, in their holding position.

For this, we first insert the inserts 21 at an external portion of the inter-blade space 15, as shown in Figure 9, then move the inserts 21, for example through the portion of gripping 31, in the radial direction DR, along the arrow F, that is to say inwards, until reaching the holding position. The term “external portion of the inter-blade space 15” means a portion defined between the center of the blade 5 in the radial direction DR and the outer end of the blade 5. Alternatively, the inserts 21 are placed directly at their holding position by a movement which follows the shape of the first and second contact surfaces 27, 29, thanks to the gripping portion 31 which forms, in this variant, a lever arm and which allows to exert sufficient force on the insert 21 to insert it directly in the holding position.

For example, to position and maintain the inserts 21 in the holding position, the positioning ring 35 can be placed so that the oblong slots 37 are at the level of the holding position of the inserts 21. Thus, when the inserts are mounted, and face the oblong slots, they are fixed to the positioning ring 35, here by means of the fixing members 39 which can be inserted in the blind holes 37 of the inserts 21.

Once all the inter-blade spaces 15 of the impeller 1 is provided with an insert 21, the disc 2 can be removed. After having removed the disc 2, one can, for example, proceed replacing the retaining ring 17. Then, it is possible to re-engage the disc 2 with all of the blade roots 7 of the blades 3, since their relative position has been maintained by the inserts. Finally, once the blades 3 have been reassembled on the disc 2, the holding system 19 can be removed.

A second embodiment of the holding system is shown in Figure 8. In what follows, the elements common to the various embodiments are identified by the same reference numerals. The second embodiment differs from the first embodiment in that the inserts 21 each comprise a first member 41 and a second member 43. The first and second members 41, 43 are configured to be arranged, in an inter-blade space 15 The first member 41 is disposed against the blade 5a of the first blade 3a and the second member 43 is disposed against the blade 5b of the second blade 3b, circumferentially adjacent to the first blade 3a. The first and second members 41, 43 face each other in the circumferential direction of the impeller.

The inserts 21 further each comprise a clamping piece 45, configured to be inserted, in the axial direction DA, between the first and second members 41, 43, so as to maintain the first and second members 41, 43 against the blades 5a, 5b. In the embodiment shown, the clamping piece 45 has a wedge or bevel shape.

In order to guide the clamping piece 45 between the first and second members 41, 43 when it is inserted in the axial direction and therefore avoid its radial displacement, at least one of the first and second members 41, 43 comprises a surface guide. In the example shown, each of the first and second members 41, 43 comprises a guide surface.

The guide surfaces are here formed by grooves 47, 49, formed in each of the first and second members 41, 43. The edges of the grooves 47, 49 allow the radial locking of the clamping piece 45 and a guide in axial translation of the clamping piece 45.

In one embodiment, not shown, the clamping piece 41 comprises an axial stop configured to come into contact with the first and second members 41, 43 when the clamping piece 45 is mounted between the first and second members 41, 43.

For example, in order to position the inserts 21 at the same radial height in the inter-blade spaces according to the embodiment shown in FIG. 8, an internal disc 34 of radial stop could be provided at a predetermined height , corresponding to the holding position of the inserts 21. The first and second members could be positioned in abutment against the internal disc 34, before the insertion of the clamping piece.

The method for removing the impeller 1 using a holding system according to the second embodiment is described below.

For this, there is the first member 41 of an insert 21 against the blade 5a of the first blade 3a, at the holding position. Then, the second member 43 of the insert 21 is placed against the blade 5b of the second blade 3b, circumferentially adjacent to the first blade 3a, also at the level of the holding position, so that the second member 43 is arranged in face of first member 41 in the circumferential direction of the impeller. Then, the clamping piece 45 is inserted between the first and second members 41, 43.

Inserts 21 are thus inserted into each of the inter-blade spaces 15.

Once all of the inter-blade spaces 15 of the impeller 1 is provided with an insert 21, in the same manner as in the first embodiment, the disc 2 can be removed. removed the disc 2, we can, for example, replace the retaining ring 17. Then, we can easily re-engage the disc 2 with all of the blade roots 7 of the blades 3, since their relative position has been maintained by the inserts. Finally, once the blades 3 have been reassembled on the disc 2, the holding system 19 can be removed.

Although the present invention has been described with reference to specific embodiments, it is obvious that modifications and changes can be made to these examples without departing from the general scope of the invention as defined by the revendications. In particular, individual features of the different illustrated / mentioned embodiments can be combined in additional embodiments. Therefore, the description and the drawings should be considered in an illustrative rather than restrictive sense.

It is also obvious that all the characteristics described with reference to a method can be transposed, alone or in combination, to a device, and conversely, all the characteristics described with reference to a device can be transposed, alone or in combination, to a method.

Claims

1. Holding system (19) for removing a paddle wheel

(1), the impeller (1) comprising:

- a disc (2),

- a plurality of blades (3) configured to be mounted circumferentially around the disc (2), the plurality of blades (3) defining a plurality of inter-blade spaces (15), the inter-blade spaces (15) each being defined circumferentially between two adjacent blades (3a, 3b) of the plurality of blades (3),

the holding system (19) comprising a plurality of inserts (21), each of the inserts (21) being configured to be inserted in each of the inter-blade spaces (15) in a holding position so as to maintain the relative position blades (3) when the plurality of blades (3) is removed from the disc (2).

2. holding system (19) according to claim 1, in which each of the inserts (21) comprises at least one portion made of an aluminum-based alloy, and / or a polymer having a shore hardness of between 75 and 100 .

3. holding system (19) according to one of claims 1 or 2, wherein the inserts have a thickness (e) in a radial direction (DR) greater than or equal to 10% of the height (h) of a blade of a blade in the radial direction (DR).

4. holding system (19) according to one of the preceding claims, comprising a gripping portion (31) configured to be mounted on an insert (21) of the plurality of inserts, the gripping portion (31) being configured to allow gripping of the insert (21) and facilitate mounting of the insert (21) in an inter-blade space (15).

5. Holding system (19) according to one of the preceding claims, comprising a positioning device (33, 34) of the plurality of inserts, each insert (21) of the plurality of inserts being configured to be attached to the positioning device (33, 34) so as to keep the inserts (21) in position.

6. Holding system according to claim 5, wherein the positioning device (33) comprises a positioning ring (35), the positioning ring (35) comprising fixing elements (37) to allow the fixing of the inserts (21) on the positioning ring (35).

7. holding system (19) according to one of claims 1 to 3, in which the inserts (21) each comprise:

- A first member (41) and a second member (43), the first and second members (41, 43) being configured to be arranged in an inter-blade space (15), the first member (41) being disposed against a first blade (3a), and the second member (43) being disposed against a second blade (3b) circumferentially adjacent to the first blade (3a); and

- A clamping piece (45), configured to be inserted between the first and second members (41, 43) so as to maintain the insert (21) between the first and second blades (3a, 3b).

8. Method for dismantling an impeller (1) comprising a disc (2) and a plurality of blades (3) mounted circumferentially around the disc (2), the plurality of blades (3) defining a plurality of 'inter-blade spaces (15), the inter-blade spaces (15) each being defined circumferentially between two adjacent blades of the plurality of blades (3), the disassembly method comprising the following steps:

A. inserting a plurality of inserts (21) of a holding system (19) into the inter-blade spaces (15) in a holding position so that the relative position of the blades (3) is maintained; B. remove the disc (2).

9. The method of claim 8, wherein during step A:

- The inserts are inserted at a radially external portion of the inter-blade spaces (15);

- The inserts (21) are moved in a radial direction (DR), radially inward, until reaching the holding position. 10. The method of claim 8, wherein the inserts (21) each comprise a first member (41), a second member

(43) and a clamping piece (45), during step A:

- There is the first member (41) of an insert (21), in an inter-blade space (15), against a first blade (3a) at the holding position;

- the second member (43) of the insert (21) is placed in the inter-blade space (15), against a second blade (3b), adjacent to the first blade (3a), so that the second member (43) is arranged circumferentially opposite the first member (41);

- Inserting the clamping piece (45) between the first and second members (41, 43) so as to maintain the insert (21) in the holding position.