DE2603862A1 - METHOD OF MANUFACTURING TURBINE BLADES - Google Patents

Description

177/75 Hw / approx

12/22/75

BBC Aktiengesellschaft Brown, Boveri & Cie., Baden (Switzerland)

Process for manufacturing turbine blades

The present invention relates to a method for producing rotor blades and guide vanes for turbines, which are made from an airfoil provided with a profile, in particular consist of a drawn blade material, a fastening foot and a cover plate.

Various types and shapes of blades are used in turbines, both rotor blades and guide blades. It uses blades without upper cover plates and with fasteners and spacers, as well as turbine blades with riveted shrouds, combined with various types of puss or fastening, and shovels with Cover plates for each individual blade, which, however, are always made from a workpiece, for example by Milling from a full block of material.

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In the case of the blade types listed above, the production is usually very complex and expensive, especially in the With regard to the efficiency achieved by the blades. In particular for the manufacture of rotor blades, a high A degree of accuracy is required, especially with regard to the uniform weight of the blades and their fastening device. This results in further complex and expensive designs.

It is the object of the present invention to provide a method for producing rotor blades and guide blades for turbines, which can be used for all types of blades, which is cheap to manufacture and easy to use the fastening of the blade root.

The aforementioned object is achieved according to the invention by the following process steps:

a) The cover plate is processed in such a way that it has an airfoil profile on its part facing the airfoil has the same profile contour,

b) the cover plate is connected to the blade by welding, the surface of the blade being perpendicular to stand on the outer surface of the profile, even if

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the flow channel opposite the blade trailing edge is inclined

c) the weld seams are made by fine-tuning the profile surface customized,

d) the drawn rotor blades are compressed at their foot ends until they have a T-shaped design have so that they are held in intermediate pieces.

The advantage of the aforementioned method can be seen in particular in the fact that the turbine blades can be manufactured independently of the blade length of the individual blades is the same for all turbine blade types. The weld seam between the blade and the cover plate is not in a place of high stress concentration and is therefore great forces exposed. Furthermore, the stress level at the weld seam is much lower than at the blade root, which affects the material does not have an unfavorable effect due to the heating during welding. Furthermore, the pre-machined cover plate can be reworked with little time-consuming pre- or grinding work. Due to the compression of the rotor blades Radial centrifugal forces can occur at the foot ends and the upset foot ends are embedded in intermediate pieces easily pick up.

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According to a further process step for the production of guide vanes, the drawn vane blades for the guide vanes at the foot end of the vane nose have a groove for making one in the vane groove and one in the same groove the intermediate pieces inserted fastening wire provided.

Since the guide vanes do not have to absorb any radial centrifugal forces, it is sufficient to fasten them with intermediate ^{pieces and a fastening wire inserted into the 1} ICut arranged in the blade nose and an identical groove in the intermediate pieces. This achieves a standardization in the manufacture of the individual blade types, ie the blanks for the guide and rotor blades can be manufactured identically. The final assignment only needs to be made before installation.

In the drawing is an embodiment of the according to the invention Process produced blades and guide vanes shown in simplified form.

It shows:

Fig. 1 The arrangement of two blades in a rotor, FIG. 2 shows a side view of a rotor blade according to FIG. 1, FIG. 3 shows a perspective view of a guide blade, 4 shows a rotor blade in a perspective illustration.

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According to Fig. 1, 1 designates a rotor groove in which Rotating blades 2 are inserted with their upset feet 3 between intermediate pieces 4. At the top of the blade 2 cover plates 5 are provided which are welded to the blades of the rotor blade 2 by means of weld seams 6 are. As a welding process for welding the cover plates 5 to the blades of the rotor blades 2 can Electron beam welding, friction or resistance welding can be used.

In FIG. 2, in the side view of the rotor blade 2 according to FIG. 1, the weld seam 6 is particularly clearly visible, it can also be seen that the surface of the weld seam 6 is perpendicular to the profile outer surface of the rotor blade 2 comes to a standstill, even if the flow channel is inclined with respect to the blade trailing edge of the rotor blade 2 is (see angle oC).

and FIG. 3 shows a guide vane 7 with the welded seam of the cover plate 5, which is attached to its vane nose 8 has a groove 9 at the foot end, which corresponds to an identical groove 9 * in the two intermediate pieces 4, and into which a fastening wire (not shown) is inserted for fastening.

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In the rotor blade 2 according to Fig. ^ J, the upset foot 3 is ^{clamped under the Zxvischen pieces 1} J, while the groove 9 ¹ for the insertion of the fastening wire is arranged so that the blade nose 8 of the blade 2 is not touched.

By the method described above, it is possible to create airfoils To be used with the same profile for different turbines, since the blades are before the Sehaufefus 3 is compressed can be cut to the appropriate length. There is also the post-processing of the weld seams on the blade easy to carry out, so that there are no disadvantages in terms of flow.

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Claims (3)

177/75 claims - * k> * ■ 1. Method of manufacturing rotor blades and guide vanes for Turbines, which are made from a profiled Blade, in particular made of a drawn blade material, a fastening foot and a cover plate, characterized by the following process steps: a) The cover plate (5) is processed in such a way that it is at its the part facing the blade has a profile similar to the blade profile, b) the cover plate (5) is welded to the blade connected, whereby the planes of the weld seam (6) come to stand perpendicular to the outer surface of the profile, itself when the flow channel is opposite the blade trailing edge is inclined c) the weld seam (6> are adjusted by fine processing of the profile surface, d) the pulled blades (2) are at their foot ends (3) compressed until it is T-shaped have so that they are held in intermediate pieces (4). ORIGINAL INSPECTED 709827/0524 -Ψ- 177/75 2. ¥ experience according to (9 ^f ) in the intermediate pieces (4) inserted fastening wire is provided. 3. The method according to claim 1 and 2 »characterized in that the weld seam between the blade and the Cover plate (5) ends in front of the blade trailing edge. BBC Public Company Brown, Boveri & Cie. 709827/0524