DEVICE AND METHOD FOR SECURING COVER BANDS TO STATOR BLADES

Description

Technical Fields

[0001] The invention involves a method for securing stator blade fixing covers and devices used for implementing the method.

Background Arts

[0002] The stator ring blades are fixed with a cover along their internal diameter. The cover is not attached to the blades during the manufacturing process as it is only fixed to the blades after inserting and fixing the stator ring in the turbine support where the stator rings are fixed firmly. Protruding rivets on stator blades must be manually protracted onto the individual small cover parts according to actual condition of blades fitting so that drilling of the openings for placing the cover parts on the specified number of rivets is carried out according to it. Such drilled openings are used for inserting the rivets located at the end of stator blades. However, the opening and rivet tolerances are so small that some of the rivets have to be forced into the openings using a brute force while both the fixing rivet and the actual stator blades are damaged. When all the cover parts are fitted at the ends of stator blades with protruding rivets, a human factor and labour are needed with the following consequences: uncontrolled manual work characteristic for its high labour consumption, strong vibrations that negatively influence human organism, and primarily the inability to apply proper power on the rivets causing their overload and different heights of rivet heads that need to be lathed down to the same height.

[0003] A device for implementing the method for securing the stator blade fixing covers is not known and the method is still being implemented using a combination of a number of procedures and devices, especially the hand held riveting hammer.

[0004] As the general state of the prior art which is closest to the subject-matter of presented solution can be considered following documents: US 4137620 A, EP 0393567 A1, US 4437213 A, US 2007/074554 A1.

Disclosure of Invention

[0005] The disadvantages are prevented by the method for securing stator blade fixing covers while its principle lies in inserting blades in a blade ring freely without any fixing. The outer ends of blades are inserted in the inner face of a blade ring. The blade ring is located on rotating segments and side-secured by top segments. Rotating segments ensure support from the bottom of the ring and at the same time rotation of the ring. Top segments are located in upper half of the blade ring. Blade rivets are inserted in the cover one after another. Blade rivets are part of blades. Blade is made from one part of the material, rivet is on the top of the blade and it is part of the whole. The blade with its bottom part inserted in the blade ring, together with the blade ring, stands on a firm surface and is secured in a cover by clenching the rivet with a riveting head. When the securing is complete, the entire blade ring is rotated using rotating segments to secure the next rivet, i.e. the entire ring is rotated so that next blade is in a position perpendicular to the solid surface again. The procedure is applied until all blade rivets in a cover are secured.

[0006] The greatest advantage of the method for securing the stator blade fixing covers and implementing the method is the fact that it is a controlled riveting process where the power is applied accurately and the rivets are not overloaded. Riveting is always performed in the rivet axis. It achieves high accuracy allowing avoidance of the stator blade deformation when placing the actual cover on the rivets. Thanks to using the device for implementing the method, the worker is not exposed to strong vibrations during manual riveting and their health is not being damaged.

[0007] Disclosed herein is a method according to claim 1 for securing a stator blade fixing cover and consisting of these steps:

1. inserting stator blades into the blade ring without fixing in such a way that blade rivets are positioned towards the wheel center

2. placing the blade ring on rotating segments and on solid surface, and securing the blade ring from side movements by top segments

3. placing the blade rivets into cover openings prepared in advance

4. fixing the cover to the blade sitting directly on the solid surface together with the blade ring by securing the rivets using a riveting head located in the internal area of the cover

5. rotating the entire blade ring using rotating segments in such a way that next blade can be secured

6. applying such procedure until all blades are secured

7. removing the blade ring.

[0008] A device according to claim 2 for implementing the method for securing the stator blade fixing covers is also disclosed and consists of:

• a frame
• rotating segments whereon blade ring is placed
• top segments to side-secure blade ring
• a solid surface
• a riveting head located in the internal circular are of the cover for fixing the cover to the blade sitting directly on the solid surface

Brief Description of Drawings

[0009] The technical design will be further clarified by the drawing, where fig. 1 shows the device for implementation of securing the stator blade fixing covers seen from the front.

Mode for carrying out the invention

Example 1

[0010] The method for securing stator blade fixing covers is carried out by blades 5 being freely inserted in a blade ring 4 without any fixing. The actual blade ring 4 is located at the sides on rotating segments 6 and side-secured by top segments 7, at the same time, its bottom side stands on a solid surface 2. Rivets 8 of the blades 5 are inserted into a cover 3, while the blade 5 is inserted in the blade ring 4, so that it stands on the solid surface 2. The blade is secured in the cover 3 by securing the rivet 8 using a rivet head 1. When the task is completed, the entire blade ring 4 is rotated using rotating segments 6 to secure the next rivet 8. This method is applied until all the blades 5 are fixed in the cover 3.

Example 2

[0011] The device for implementing the method for securing the stator blade fixing covers is composed of a frame with rotating segments 6 and top segments 7 placed on it for fixing the blade ring 4 that always stands with the bottom perpendicularly inserted blade 5 on a solid surface 2. The riveting head 1 is located in the internal circular cover 3 area.

Example 3

[0012] The blade ring 4 is placed on rotating segments 6 and solid surface 2. It is secured from side movement by top segments 7. Blades 5 are inserted into the blade ring in such a way that the rivets 8 are positioned towards the ring centre. Blade 5 rivets 8 prepared in such way are placed into the cover 3 openings prepared in advance. A riveting head 1 located in the internal area of the blade ring 4 and as a matter of fact in the internal area of the cover 3, secures the rivet 8 causing its deformation hence fixing the cover to the blade 5. The blade 5 under such application is located on the solid surface 2 and, together with the blade ring 4, it sits directly on it. Thus, the least dissipating energy transfer is used. Further, the entire blade ring is rotated using rotating segments 6 in such a way that the next blade can be secured. This is applied until all the blades are secured. When this process is complete, the blade ring 4 is removed and blades 5 are secured in the actual blade ring 4.

Industrial Application of the Invention

[0013] The invention can be applied in the current spacing ring manufacturing allowing the production of ready-made spacing rings with fixed blades, including their covers. Up until recently, the cover used to be fixed only after fitting the distance ring in the turbine while, from the prospective of handling during the tasks performance, this was grossly non-ergonomic and, in extreme cases, it could also lead to damaging the turbine being assembled. Thus, in comparison to the existing procedures, the method developed is more effective, faster, as well as less costly financial-wise.

Claims

1. Method for securing a stator blade fixing cover (3) characterized in that blades (5) are inserted in a blade ring (4) freely without fixing, after that the blade ring (4) is placed standing on rotating segments (6) and side-secured by top segments (7), its bottom side standing on a solid surface (2), then for the bottom blade (5) inserted in the blade ring (4) and standing on the solid surface (2), blade rivets (8) are inserted into a cover (3) and the blade (5) is secured in the cover (3) by securing rivets (8) using a riveting head (1), after that the rotating segments (6) perform a rotation of the entire blade ring to secure the next rivet (8), and such procedure is applied until all the blades (5) are fixed in the cover (3).

2. Device for implementing the method for securing the stator blade fixing covers of claim 1, characterized in that it comprises a solid surface (2) and a frame with rotating segments (6) and top segments (7), configured so that, in use, a blade ring (4) can be placed standing on the rotating segments (6) and side-secured by the top segments (7) and the blade ring (4) always stands with the bottom perpendicularly inserted blade (5) standing on the solid surface (2), and a riveting head (1) located in the internal circular area of the cover (3) when in use for fixing the cover (3) to the blade (5) sitting directly on the solid surface (2).

Ansprüche

1. Methode zur Absicherung des Befestigungsdeckels der Schaufeln (3), charakterisiert dadurch, dass die Schaufel (5) frei und unbefestigt auf den Schaufelkranz (4) eingesetzt wird, und danach der Schaufelkranz (4) stehend auf Rotationssegmenten (6) mit den oberen Segmenten (7) auf der Seite abgesichert wird, wobei die Unterseite auf einer festen Unterlage (2) liegt, dann mit der unteren Schaufelteil (5) in den Schaufelkranz (4) eingesetzt und auf einer festen Unterlage (2) liegend, die Schaufelniete (8) in den Deckel (3) eingesetzt werden und die Schaufel (5) mit Nieten (8) auf den Deckel (3) mit Hilfe eines Nietkopfes befestigt wird, danach werden die Rotationssegmente (6) auf dem Schaufelkranz gedreht, um den nächsten Niet (8) absichern zu können, und dieses Verfahren wird solange durchgeführt, bis alle Schaufeln (5) auf dem Deckel (3) befestigt sind.

2. Die Vordichtung zur Durchführung der Methode zur Absicherung gemäß Patentanspruch 1, charakterisiert dadurch, dass sie feste Unterlage (2) und einen Rahmen mit Rotationssegmenten (6) und oberen Segmenten (7) hat und so gestaltet ist, dass bei Verwendung der Schaufelkranz (4) auf Rotationssegmente (6) stehend gestellt werden kann und auf der Seite mit den oberen Segmenten (7) abgesichert werden kann, und der Schaufelkranz (4) immer mit der senkrecht eingesetzten Schaufel (5) auf der festen Unterlage im unteren Teil steht, und der Nietkopf (1) in der inneren Kreisfläche des Deckels (3) bei Befestigung des Deckels (3) zur Schaufel (5) positioniert ist, die direkt auf der festen Unterlage (2) liegt.

Revendications

1. Le procédé de montage des aubes de stator sur un carter (3) est caractérisé par le fait que les aubes (5) sont insérées librement et sans fixation dans un anneau d'aubage (4), l'anneau d'aubage (4) est ensuite placé sur des supports rotatifs (6) et maintenu latéralement par des supports supérieurs (7), sa surface inférieure reposant sur une surface solide (2), puis l'aube inférieure (5) est insérée dans l'anneau d'aubage (4) et repose sur une surface solide (2), les rivets de l'aube (8) sont insérés dans le carter (3) et l'aube (5) est fixée au carter (3) par rivetage des rivets (8) à l'aide d'une tête de rivetage (1), après quoi les supports rotatifs (6) permettent d'effectuer une rotation de tout l'anneau d'aubage (4) pour fixer les rivets suivants (8) et cette procédure est renouvelée jusqu'à ce que toutes les aubes (5) soient fixées au carter (3).

2. Le dispositif de mise en oeuvre du procédé de montage des aubes de stator sur un carter selon la revendication 1, est caractérisé par le fait qu'il est constitué d'une surface solide (2), d'un bâti comprenant des supports rotatifs (6) et des supports supérieurs (7) qui sont configurés de façon à ce qu'un anneau d'aubage (4) puisse être placé sur les supports rotatifs (6) et maintenu latéralement par les supports supérieurs (7) l'anneau d'aubage (4) est toujours placé de manière à ce que l'aube inférieure à insérer (5) soit perpendiculaire au carter et repose sur la surface solide (2) et une tête de rivetage (1) placée dans le volume cylindrique interne du carter (3) et destinée à fixer sur le carter (3) l'aube (5) reposant directement sur la surface solide (2).

Drawing