JPH03267504A - Repairing of turbine blade - Google Patents

Abstract

PURPOSE: To make possible the repair of a turbine blade in a state where it is installed in a rotor by relatively moving a lacing wire member circumferentially to remove the wire member from a blade to be repaired. CONSTITUTION: After the connections of respective members 21 to 24 of a lacing wire 20 are entirely released, the respective members 21 to 24 are relatively moved circumferentially clockwise or counterclockwise. Thus, the racing wire 20 can be removed from a blade 15 to be repaired, and thereby the blade 15 can be repaired in state where it is installed in a rotor 10.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention This invention relates to the repair of turbine blades, and more particularly to the repair of turbine blades in turbine blade assemblies having a plurality of blades connected by lacing wires. Such lacing wires are wires, rods or other members that pass through holes in the blades and connect multiple blades;
Its purpose is to prevent excessive relative displacement between the blades and to generally dampen any vibrations during turbine operation.

BACKGROUND OF THE INVENTION As noted above, lacing wires may be wires, rods, tubes, or other members, and are conveniently referred to herein as lacing wires.

During use of the turbine, the blades receive steam or the like.

Because the blades are subjected to such high forces, other damage may occur, such as cracks that require removal and replacement of the entire turbine blade. If the damage is not too severe, the damage may be repaired by repairing the blade.

British Patent Specification No. 2.091.139 discloses a method for repairing turbine blades, which method involves repairing the racing wire holes with welding material before performing any welding or soldering operations in the vicinity of the racing wires. It includes a filling process. When the Brevi is subsequently subjected to a stress relieving heat treatment, the discontinuities caused by the racing wire holes have been removed, thereby eliminating the inbuilt heat treatment caused around the racing wire hole gaps.
(built-in) Stress generation is prevented.

Such a method of repair has been found to be very satisfactory. However, there are the following problems. In other words, in an improved method and installation where a turbine blade is repaired while the blade remains attached to the rotor, if adjacent breviations are in close proximity, it is difficult to remove the racing wire from the hole and fill the hole. , it is impossible to insert a new racing wire without completely cutting the racing wire, and it is impossible to insert a new racing wire without removing the blade from the rotor.

In reality, the lacing wire consists of several pieces of material, the ends of which are formed overlapping each other to allow a degree of relative movement between the pieces. There is.

In other examples, the lacing wire is secured to the blade through which it leads, for example by a tack weld or braze material, and a small gap exists between the ends of adjacent lacing wires. The turbine blades are effectively connected together.

In some cases, it is not necessary to fill the lacing wire holes. However, the problem remains that, for example, with the lacing wire attached to the blade, access to the blade is not possible and the lacing wire must be removed from the blade in order to perform a satisfactory repair.

It is an object of the present invention to provide a new method for repairing such turbine blades.

SUMMARY OF THE INVENTION According to a first aspect of the invention, a method for repairing a turbine blade of the lacing wire type is provided.

This method includes: (a) breaking all connections between the racing wire and blades in operation of the turbine being repaired and adjacent to the blade being repaired; (b) breaking all connections between adjacent members making up the racing wire; (c) relative circumferential movement of the racing wire member clockwise and/or counterclockwise to move the racing wire member away from the blade to be repaired; (d) the lacing performing a repair process on the blade after the wire has been removed from the blade to be repaired; (e) in a direction opposite to the direction in which the member forming the lacing wire was moved so that the lacing wire returns to its proper position; and (f) regenerating the broken connections to enable said movement.

Preferably, the repair process involves a welding or soldering process (br
azing), the blade is subjected to a heat treatment step to relieve stresses in the blade caused by these treatments performed on the blade.

If repairs need to be made to one or more turbine blades, the lacing wires are attached to the turbine so that after one blade has been repaired, the lacing wires are removed from engagement with the adjacent turbine blades that are subsequently repaired. The blades are moved clockwise or counterclockwise around the row of blades and each blade in need of repair is repaired in turn. After all blade repairs are completed,
The lacing wire assembly is reconnected.

In some types of turbine blade arrays, the lacing wire is constructed from a number of individual members, each having an end that overlaps an adjacent lacing wire member. If it is necessary to remove the racing wire from at least one blade in order to make a repair, a slight bending of the end portions of adjacent racing wire members is performed, and then the racing wire members are circumferentially folded as described above. By moving in the direction, two adjacent lacing wire members are moved to overlap one another. If further movement is required, one of the blades may be provided with a hole through which essentially two parts of the lacing wire pass, in order to prevent the lacing wire from being unduly deformed or bent. It is also possible to provide other holes in the blade adjacent to the holes in which the existing lacing wires are located.

If the damage to the turbine blade is severe, it may be necessary to remove the racing wire from the blade in order to perform proper repair.

If the lacing wire is to be replaced with a new lacing wire, there is no problem with its removal since the lacing wire is cut from the blade and the cut portion is removed. However, replacing the lacing wire with a new one creates a number of problems when the turbine blades remain arranged in rows.

According to another aspect of the invention, a method of repairing a turbine blade that requires removal and replacement of a racing wire is provided. The repair method includes: (a) removing at least a portion of the racing wire from the blade being repaired; (b) performing a repair process on the blade being repaired; and (c) inserting a new racing wire member into the row of turbine blades. forming a hole in at least one turbine blade sized to permit insertion thereof; (d) moving the lacing wire member around the row to a position out of contact with the blade in which the hole is formed; and (e) (f) moving the racing wire members into proper position; and (g) regenerating the racing wire members to interlock with each other and with the blade.

Preferably, the hole is a slot, typically a slot extending from the lacing wire hole to the leading or trailing end of the turbine blade.

In some types of turbine blades, the blades adjacent to the slotted blades have elongated holes or slots to facilitate insertion of the running wire member into the row of turbine blades.

As an individual lacing wire member is inserted into a row, the lacing wire member is moved around the row and additional lacing wire members are inserted until the lacing wire is complete.

The lacing wire is moved to a position where it first makes contact with the blade that formed the slot so that the slot and/or hole can be filled after the lacing wire member returns to its correct position, and then the individual lacing wire and/or
Or all the necessary connections between the blades of the row are made.

In some cases, the racing wires themselves may be damaged, making it necessary to remove them from the turbine blade row. The lacing wire will be reinserted after the repair is completed.

According to yet another aspect of the invention, a method of repairing a turbine blade that requires removal and replacement of a racing wire is provided. The method of repair includes: (a) forming a hole in at least one blade through which the racing wire passes; (b) forming said hole next to the hole through which the racing wire passes; and (c) connecting the racing wire with said row. (d) releasing all connections connecting adjacent members constituting the racing wire; (e) causing relative movement in the circumferential direction of the racing wire; (fl) A turbine blade such that one end of the racing wire member can be biased from its normal position to the front or leading end or the rear or trailing end of the turbine blade in order to remove the racing wire member from said row. In this method, a certain degree of lateral movement is achieved by the holes formed in the hole.

The hole may be oval in shape and extend from a position adjacent to the hole in the blade through which the lacing wire passes toward the trailing or leading end of the blade.

In one species, the hole may be a slot extending from the lacing wire hole in the blade toward the leading or trailing end of the turbine blade.

If the turbine blades in a row are closely spaced together, a combination of holes and slots may be required to remove the racing wire members.

Removing racing wire members in this manner is necessary when the racing wire must be removed for proper repair of the turbine blade and when it is desirable to replace the original racing wire of the blade. becomes.

If it is necessary to remove the lacing wire, and if it is desired to replace the lacing wire member with a new member, it is not necessary to remove it by the method described above, but by simply cutting the lacing wire member and removing this section from the row. good. However, in order to replace the racing wire member with a new racing wire member without damaging the racing wire and blades, one or more of the turbine blades may be provided with holes and/or slots and a return operation that is the reverse of the removal operation may be performed to remove each lacing wire member. It is then necessary to reinsert the wires into the perforated and/or slotted blades and move each lacing wire around the row until all the parts forming the lacing wire are returned to their proper positions. Reconnections between parts are then performed if necessary, blades are reconnected if necessary, and holes and/or slots are filled.

Holes or slots may be provided in one or more blades of the row to allow removal of the lacing wire from the blades.

According to yet another aspect of the invention, there is provided a method of repair comprising, in addition to the foregoing method, removing a racing wire from a blade to be repaired, the method further comprising: (a) removing said racing wire; (b) heat treating said blade to relieve blade stresses caused by welding or soldering acting on the blade to be repaired; and (c) ensuring that said lacing wire is in proper position. (d) regenerating all the connections that have been released to enable said movement.

Preferably, turbine blade repairs are performed in situ. However, if it is necessary to remove a blade from a row, such removal from the row can only be done after the lacing wire has been removed from the blade. In this way, blades may be removed from the row in order to perform a repair process.

Preferably, if the repairs performed involve significant thermal energy, such as occurs in welding or soldering, the blade should undergo a heat treatment step to relieve stress in the blade after the welding or soldering operation. The lacing wire holes are filled with material prior to the welding or soldering to aid the stress relief heat treatment process and reduce cracking in the blade.

Some turbine blade assembly structures do not allow sufficient circumferential movement of the members forming the racing wire in order to remove the racing wire member from the blade and perform repairs.

In this case, a portion of the lacing wire may be removed to provide sufficient clearance to allow movement of the members forming the lacing wire so that the lacing wire can be removed from at least one blade.

If a portion is removed in this way, after said step the sleeve-like member is fixed to the lacing wire member by crimping, welding, soldering, or
Repair of the lacing wire may be effected by securing the two parts by other suitable means.

If a portion of one or more members forming the lacing wire is removed, there is no need to subsequently repair the lacing wire. However, the gaps that exist between the racing wire members forming the racing wire are slightly larger when viewed as a whole.

In some cases, for example, only one or two blades in a row of 15 or 16 blades may require repair, in which case in order to free one or two blades from the lacing wire, The effort and time required to release all the members forming the lacing wire becomes unnecessarily time consuming.

In this case, replacing the lacing wire would require some degree of circumferential movement of the members forming the lacing wire; The lacing wire member must be replaced to allow insertion. Such members shall then be joined in a suitable manner, for example by welding, soldering or by welding or soldering a sleeve to the end of the lacing wire member or by staking in place. Must be.

It has been found that removing the racing wire from the turbine blade row can significantly improve repair efficiency in many cases. Access to the blade to be repaired is easy, which is particularly useful when there is limited space available with adjacent blades and therefore the repair must be performed in situ.

Additionally, removing the lacing wire allows one person to repair blades on one side of the row while another person repairs the blades on the other side at the same time when repairing more than one blade at the same time. effective.

Since turbine down times must be addressed quickly, it is important that the repair process be carried out as quickly as possible.

EXAMPLES Hereinafter, the repair method of the present invention will be explained in detail with reference to the drawings.

In FIG. 1, a part of a turbine blade bank is shown, which comprises a rotor 10 with a rotating shaft 11. In FIG. 12 is an axis of rotation of the shaft 11. A series of turbine blades, three of which are designated 13, 14.15, are located at the base 16.
．． It is attached to the shaft 11 at 17.18. The lacing wire is generally indicated by the reference numeral 20 and is composed of a plurality of different lacing wire members, for example 21, 22, 23, 24, . . . . Each of these lacing wire members may consist of a tube or rod having a cross-sectional shape, as shown in FIG.

The ends of each member of the racing wire are usually slightly bent so that any relative movement will cause the end to contact the turbine blade and prevent excessive "rotation" of the racing wire member. ing.

One of the blades, for example blade 15 shown in FIG.
In order to remove the racing wire from the racing wire 20, any connection between the racing wire 20 or the individual members forming the racing wire 20 and the turbine blade is broken. For example, if a riveted weld has been made, the riveted weld can be removed and the member forming the lacing wire moved from the blade 15 to the diametrically opposite side of the axis of rotation 12.

Since a small gap exists between the curved end portions of adjacent blades, closing this gap creates a larger gap. The lesing wire is thus removed from one blade 15. 1 racing wire 20
In some cases, it may not be possible to provide sufficient movement to allow removal from one blade. In that case, one or more members forming the lacing wire 20 may be cut to remove a portion of the lacing wire, and then that portion may be replaced or other portions may be inserted as described below.

Once the racing wire 20 is removed from the blade, assuming the blade to be repaired is blade 15, the blade 15 will be removed from the rotor if necessary, or left in place if it does not need to be removed from the rotor. Remove the lacing wire as the repair is being done.
The lacing wire holes can be filled prior to any stress relief heat treatment of the blade.

After the repair process is performed and the heat treatment is completed, the lacing wire hole is drilled and the lacing wire is moved in the opposite direction towards the blade 15 to its normal position. Fixing the lacing wire member to the blade row is in any case carried out subsequently.

Next, different lacing wires are shown in FIG. 4, according to which, for example, the code 30° 31.32.3
The blades in the row indicated by 3 are fixed with grooves.

In the illustrated example, two blades constitute one group. However, in reality, a considerable number of turbine blades may be constructed as a group based on one racing wire member. For example, the blades 31 and 32 are secured together by lacing wire members 35.

The racing wire member 35 may be in the form of a rod or a tube, and may be fixed to one, more than one, or all of the blades in groups.

The lacing wire secures each blade to each other, for example by rivet welding. Such welds are each designated 36.37 on blade 31.32.

In this embodiment, the gaps 38, 39 are between the racing wire members 35 and each adjacent racing wire member 40, 41.
exists between the ends of , in which case the gap is sufficiently large;
The total number of gaps around the row is such that the lacing wire member can be moved diametrically opposite the blade being repaired to the extent that the lacing wire member can be completely removed from at least one blade to perform the repair. The amount is sufficient. In this example, the racing wire is fixed to the blade, so it would be necessary to remove such fixation before moving the racing wire member.

FIG. 5 shows a similar structure. But in this case,
The gaps 50, 51 between adjacent blades connected by each racing wire member 52, 53, 54 are too small, so that all the members forming the racing wire, e.g.
, 53, 54 to the diametrically opposite side of the blade being repaired does not completely remove the lacing wire member from one blade. In such a case, it may be necessary to remove a portion of the lacing wire from the lacing wire member 53, such as removed portion 60. The gap thus created allows movement of the lacing wire member, so that the lacing wire is completely removed from the blade being repaired. and,
After the repair of the blade, and after the repair of any other blades that have to be repaired, the lacing wire member is inserted so that a joint, such as 61, fills the gap created by the removed part. 53, welded thereto, or any other suitable method of connecting the lacing wire 53, such as soldering or staking, may be implemented.

Furthermore, by slightly increasing the gap between adjacent lacing wire members, the connecting portion 61 can be omitted. In this case, a portion would be removed at the end of the lacing wire member rather than in the middle of the lacing wire member. However, it will be appreciated that in this case the size of the portion removed must be such that a length remains such that the lacing wire member can be passed over the required number of blades.

Additionally, small sections may be removed from the lacing wires to allow sufficient movement of the lacing wires to remove one blade from the lacing wires so that repairs can be made.

In FIG. 8, three blades [30, 61, 62 are shown, all of which are connected by one lacing wire 63.

Each blade 60, 61, 62 has a respective hard metal shield 64, 65, 66 which minimizes damage due to corrosion.

The shield is usually made of stellite alloy.

Replacing corrosion shields such as those shown in 64.65.66 is a frequently performed repair method. Since not only the shield but also the portion of the blade surrounding the shield is usually corroded, the portion of the blade material to which the shield is attached will also typically be cut. Figure 9 shows the blades 60, 61, 62 when the corrosion shield has been removed.

In addition, a lacing wire 6 is used so that the hole can be closed before heat treatment.
3, a slot 67 and an oval hole 68 are formed in each of the blades 60, 61. These slots and oval holes allow some lateral movement of the lacing wire member 63 once the end 69 is freed. Also, due to the combination of lateral movement and some deformation of the racing wire member, the racing wire member is forced to move around the blades 60, 61 and 6 of the row it passes through.
2 as well as other blades.

In this embodiment, one lacing wire member is removed because it requires heat treatment of the blade, which is repaired when the lacing wire holding member is filled and the slot 67 and oval hole 68 are also filled. If only the lacing wire member 63 was required, the lacing wire member 63 would be inserted into the reshaped lacing wire hole.
It will be replaced in more than one section, and the sections will be joined later to complete the lacing wire member 63.

Once the lacing wire is removed, apart from being able to carry out proper repairs, additional very useful effects can be obtained, such as:

That is, once the lacing wire is removed from the blade, the blade can be corrected to its exact position, or any other desired position, by the application of physical force, and any force applied to the blade will cause the lacing wire to It is not transmitted to other blades.

Features expressed in the foregoing description or in the accompanying drawings as specific embodiments or means for producing a disclosed effect, or as a method or process for obtaining a disclosed result may be divided or combined in various ways. The present invention can be used to implement the present invention in the following aspects.

[Brief explanation of drawings]

Fig. 1 is an enlarged view of a part of the turbine row, Fig. 2 is a cross-sectional view of the racing wire shown in Fig. 1, Fig. 3 is an enlarged view of the turbine blade row with the racing wire removed, and Fig. 4 FIG. 5 is an enlarged view of a turbine blade row with a racing wire of another shape, FIG. 5 is an enlarged view of a turbine blade row with another racing wire, and FIG. 6 is a view of the racing wire with a portion removed. , FIG. 7 is a view of the joint after partial removal of the racing wire, FIG. 8 is an enlarged perspective view of the three turbine blades through which the racing wire passes, and FIG. 9 is a slot in the blade to allow removal of the racing wire. FIG. 9 is a view of the blade shown in FIG. 8 having been formed; 10... Rotor 11... Shaft 13, 1
4. 15, 30, 31, 32. 33...Turbine blades 20, 21. 22. 23. 24...Racing wire 40.41, 52, 53.54...Racing wire member 60.61.62...Blade 64.65.66...Leading end 67...Slot 68... Hole F16 ] 162

Claims (15)

[Claims] (1) A method for repairing a type of turbine blade equipped with a racing wire, comprising: (a) breaking all connections between the racing wire and the turbine blade to be repaired and a blade adjacent to the blade to be repaired; b) releasing all connections between adjacent members constituting the racing wire, and (c) repairing the racing wire member by relatively moving the racing wire member clockwise and/or counterclockwise in the circumferential direction. (d) performing a repair process on the blade after the lacing wire has been removed from the blade to be repaired; and (e) moving the lacing wire so that the lacing wire returns to position. A method comprising: moving said forming member in a direction opposite to the direction in which it was moved; and (f) regenerating the broken connection to enable said movement. 2. The repair process includes a welding or soldering operation on the blade, and further comprises subjecting the blade to a heat treatment process to relieve stress in the blade caused by the welding or soldering operation. Method described. (3) if one or more turbine blades in a row must be repaired, repair one blade and move said lacing wire to the adjacent blade to be repaired; 3. A method as claimed in claim 1 or claim 2, comprising the step of continuing to move the lacing wire until all blades therein have been repaired. (4) A method for repairing a turbine blade, the method comprising: (a) removing at least the part of the racing wire from the blade to be repaired; (b) performing a repair process on the blade to be repaired;
) forming a hole in at least one turbine blade sized to allow a new racing wire member to be inserted into the row of turbine blades; and (d) positioning the racing wire member in a position that does not contact the blade in which the hole is formed. (e) filling the holes; (f) moving the lacing wire members into position; and (g) connecting the lacing wire members to each other and to the blades. A method comprising the step of regenerating. 5. The method of claim 4, wherein the hole is elliptical. 6. The method of claim 4, wherein the hole is a slot extending into a leading end of the turbine blade. 7. The method of claim 4, wherein the hole is a slot extending to a trailing end of the turbine blade. (8) A hole is formed in at least one of the turbine blades for displacing the racing wire member from at least one blade in the row. The method described in. 9. The method of claim 8, wherein at least a portion of the racing wire member forming the racing wire is removed such that the racing wire member can be released from the blade being repaired. (10) A method of repairing a turbine blade requiring removal and replacement of a racing wire in a blade row having a racing wire, the method comprising: (a) forming a hole in at least one blade through which the racing wire passes; (b) forming said hole next to the hole through which the racing wire passes; (c) breaking all connections between the racing wire and the turbine blades of said row; and (d) adjacent holes forming said racing wire. (e) causing relative movement in the circumferential direction of said racing wire; and (f) removing one end of a racing wire member from said row in order to remove said racing wire member from said row. A method in which a degree of lateral movement is effected by means of the holes formed in the turbine blades such that they can be biased from position to the front or leading end or the rear or trailing end of the turbine blades. (11) The method of claim 10, wherein the hole is oval. 12. The method of claim 10, wherein the hole is a slot extending into a leading end of the turbine blade. 13. The method of claim 10, wherein the hole is a slot extending into a trailing end of the turbine blade. (14) The method according to any one of claims 10 to 13, further comprising: (a) repairing the blade to be repaired after removing the racing wire; and (b) repairing the blade to be repaired. (c) heat treating said blade so as to release stresses in said blade caused by welding or soldering acting on said lacing wire; A method comprising the steps of: moving the members forming the lacing wire; and (d) regenerating any connections that have been released to allow said movement. 15. The method of claim 1, wherein the repair of each turbine blade is performed while the turbine blade remains connected to the rotor.