JP2002180802A - Stationary blade in steam turbine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a stationary blade in a steam turbine for shortening a manufacturing process, improving performance, and easily replacing a seal fin. SOLUTION: This stationary blade 5 is constituted by shaving-out without performing welding. As a result, since heat treatment caused by the welding is not required, the manufacturing process can be shortened by that extent. Since surface roughness is not reduced by the heat treatment, the performance is improved by that extent. Since the seal fin 10 is detachably joined to an inner peripheral side shroud 7 of the stationary blade 5, the seal fin 10 can be easily replaced when the seal fin 10 is abraded.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a stationary blade in a steam turbine, and more particularly, to a stationary blade in a steam turbine in which a manufacturing process is short, performance is improved, and seal fins can be replaced. It is related to the stationary blade.

[0002]

2. Description of the Related Art A steam turbine will be described with reference to FIG. In FIG. 4, reference numeral 1 denotes a casing (wing ring or vehicle compartment). The casing 1 has a plurality of stages of stationary blades 2 arranged in a ring. Also, in FIG.
3 is a rotor. The rotor 3 includes a plurality of stages of moving blades 4.
Are arranged in a ring. By supplying steam into the casing 1, the rotor 3 rotates.

[0003] The stationary blade 2 of the steam turbine is manufactured by cutting a stationary blade alone, and the inner and outer peripheries of a group of the stationary blade are welded (for example, EBW welding) to integrate a semicircular portion. The integrated semicircle is divided into the casing 1
And is fixed by being fitted into the groove. After the stationary blade 2 is fixed to the casing 1, a seal fin (not shown) is formed on the inner periphery of the stationary blade 2 by cutting.

[0004]

However, since the conventional stationary blade 2 welds the inner and outer peripheries of a group of stationary blades alone, the heat treatment (annealing) accompanying the welding increases the manufacturing process. . In addition, during the heat treatment, the surface roughness of the stationary blade 2 is reduced due to oxidation of the surface thereof, which affects the performance.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a stationary blade for a steam turbine in which the manufacturing process is short, the performance is improved, and the seal fin can be easily replaced.

[0006]

Means for Solving the Problems In order to achieve the above object, the invention according to claim 1 is directed to a group of stationary blades manufactured by cutting, and a method of cutting a stationary blade into an inner peripheral side of the stationary blade. A shroud provided by the method, a shaving provided on the outer peripheral side of the stationary blade unit by cutting, and an implanting protrusion to be implanted into the implanting groove formed in the casing, and a plurality of pieces manufactured by shaving. And a seal fin that is detachably coupled to the shroud, is formed in an annular shape, and is fixed to the shroud via fixing means and faces the rotor. It is characterized by the following.

As a result, according to the first aspect of the present invention, since the stationary blade is formed by cutting without welding, heat treatment accompanying welding is not required, and the manufacturing process is shortened accordingly. it can. Further, since the surface roughness does not decrease due to the heat treatment, the performance is improved accordingly. Furthermore, since the seal fin is detachably connected to the shroud on the inner peripheral side of the stationary blade, the seal fin can be easily replaced when the seal fin is worn.

The invention according to a second aspect is characterized in that a pin fixing both ends of a seal fin piece and a shroud is provided;
It is characterized in that the fixing means comprises the spot welding for preventing the pin from coming off.

As a result, in the invention according to claim 2, since both ends of the seal fin piece and the shroud are fixed by the pins, the fixing is firm. In addition, since the pins can be prevented from coming off by spot welding, more secure fixing can be obtained.

According to a third aspect of the present invention, the fixing means comprises a dovetail structure in which the seal fin piece and the shroud are fixed, and a stopper for preventing the seal fin piece from rotating in the circumferential direction. It is characterized by.

As a result, in the invention according to claim 3, the seal fin piece and the shroud are fixed by the dovetail groove structure and the stopper, so that the number of parts can be reduced.
The structure is simple, and the assembly process is also simple.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a stationary blade in a steam turbine according to the present invention will be described below with reference to FIGS. In addition, the stationary blade in this steam turbine is not limited by this embodiment.

(Explanation of Embodiment) FIGS. 1 and 2
1 shows an embodiment of a stationary blade in a steam turbine according to the present invention. In the figure, the same reference numerals as those in FIG.

In FIG. 1, reference numeral 5 denotes a stationary blade according to this embodiment. The stationary blade 5 is composed of a group of stationary blade units 6 manufactured by cutting. On the inner peripheral side of the stationary blade unit 6, a shroud 7 is provided by being cut out.
Further, on the outer peripheral side of the stationary blade unit 6, an implanting projection 8 is provided by cutting.

On the other hand, the casing 1 is formed with an implantation groove 9 having a U-shaped cross section. The projecting projection 8 of the stationary blade unit 6 is implanted and fixed in the implanting groove 9 of the casing 1. The stationary blades 6 are arranged in a ring shape on the casing 1 and the seal fins 10 are provided in an annular shape on the shroud 7 on the inner peripheral side of the stationary blades 6 to form the stator blades. 5 are configured.

The seal fin 10 is composed of a plurality of pieces, in this example, eight pieces manufactured by cutting. A recess 11 for fitting is provided on the inner peripheral side of the seal fin 10. On the other hand, a projection 12 for fitting is provided on the outer peripheral side of the shroud 7.

The recesses 11 of the seal fins 10 and the projections 12 of the shroud 7 are fitted, and the pieces of the eight seal fins 10 are detachably connected to the shroud 7 to form an annular shape. . Further, by fixing the pieces of the eight seal fins 10 and the shroud 7 to each other via fixing means, the seal fins 1
0 faces the rotor 3.

The fixing means comprises a pin 13 and a spot welding 14. That is, the pins 13 are passed through both ends of the pieces of the eight seal fins 10 and the shroud 7 to fix the seal fins 10 and the shroud 7. Next, spot welding 14 is performed on the pin 13 and the seal fin 10 or the shroud 7. After fixing the seal fin 10 to the shroud 7, the seal fin 1
A finishing step of 0 may be performed.

The seal fin 10 and the shroud 7 are restrained by fixing the pin 13 and fitting the concave portion 11 and the convex portion 12 without fixing the pin 13. In other words, the seal fins 10 are those in which the seal fins themselves and the member that restrains the shroud 7 are integrated.

The stationary blade 5 in this embodiment is constructed as described above, that is, is formed by cutting without welding, so that heat treatment accompanying welding is not required, and the manufacturing is correspondingly performed. The process can be shortened. Further, since the surface roughness does not decrease due to the heat treatment, the performance is improved accordingly. Further, since the seal fin 10 is detachably connected to the shroud 7 on the inner peripheral side of the stationary blade 5, only the seal fin 10 can be replaced when the seal fin 10 is worn. Note that, when the seal fin 10 is replaced, even if the spot welding 14 is broken, there is no particular problem since the seal fin 10 itself is replaced with a new one.

The stationary blade 5 in this embodiment is
Since both ends of the eight pieces of the seal fins 10 and the shroud 7 are fixed by the pins 13, the fixing is firm. In addition, since the pin 13 can be prevented from coming off by the spot welding 14, a more secure fixing can be obtained.

(Explanation of Modification of Fixing Means) FIG. 3 is a partial sectional view showing a modification of the fixing means. In the drawing, the same reference numerals as those in FIGS. 1, 2 and 4 denote the same components.

The fixing means of this modification has a dovetail groove structure 15 in which the eight pieces of the seal fins 10 and the shroud 7 are fixed, and prevents the eight pieces of the seal fins 10 from rotating in the circumferential direction. And a stopper (not shown, for example, a buried bolt).

The fixing means of this modification fixes the pieces of the eight seal fins 10 and the shroud 7 by the dovetail groove structure 15 and the stopper, so that the number of parts is small, the structure is simple, and the assembly is simple. The process is simple.

Although the seal fin 10 is composed of eight pieces, in the present invention, the seal fin may be composed of two or more pieces. Further, the fixing means may be a bolt and nut.

[0026]

As is clear from the above, according to the stationary blade (claim 1) in the steam turbine according to the present invention,
Since the stationary blade is formed by cutting without welding, heat treatment accompanying welding is not required, and the manufacturing process can be shortened accordingly. Further, since the surface roughness does not decrease due to the heat treatment, the performance is improved accordingly. Further, since the seal fin is detachably connected to the shroud on the inner peripheral side of the stationary blade, the seal fin can be easily replaced when the seal fin is worn.

Further, according to the stationary blade in the steam turbine according to the present invention (claim 2), since both ends of the seal fin piece and the shroud are fixed by the pins, the fixing is firm. In addition, since the pins can be prevented from coming off by spot welding, more secure fixing can be obtained.

Further, according to the stationary blade of the steam turbine according to the present invention (claim 3), the seal fin pieces and the shroud are fixed by the dovetail groove structure and the stopper, so that the number of parts is reduced and the structure is reduced. Simple and
The assembly process is also simple.

[Brief description of the drawings]

FIG. 1 is a partial longitudinal sectional view showing an embodiment of a stationary blade in a steam turbine of the present invention, and is a sectional view taken along a line II in FIG. 2;
FIG. 5 is a sectional view taken along a line and an enlarged sectional view of a portion I in FIG. 4.

FIG. 2 is also a front view of a stationary blade.

FIG. 3 is a partial sectional view showing a modification of the fixing means.

FIG. 4 is a longitudinal sectional view showing a steam turbine.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 casing 3 rotor 4 rotor blade 5 stationary blade 6 stationary blade unit 7 shroud 8 implantation protrusion 9 implantation groove 10 seal fin 11 concave portion 12 convex portion 13 pin 14 spot welding 15 dovetail groove structure

Claims (3)

[Claims] 1. A stationary blade arranged in an annular shape on a casing,
In a steam turbine having a rotor and rotor blades arranged in a ring, the stationary blades are provided on the inner peripheral side of the stationary blade unit by cutting and on a group of stationary blade units manufactured by cutting. A shroud, an implant projection provided on the outer peripheral side of the stationary blade unit by cutting, and implanted in an implantation groove formed in the casing, and a plurality of pieces manufactured by cutting. And a seal fin detachably connected to the shroud and formed in an annular shape and fixed to the shroud via fixing means and opposed to the rotor. A stationary blade in a steam turbine. 2. The fixing means according to claim 1, wherein the fixing means comprises pins fixing both ends of the piece of the seal fin and the shroud, and spot welding for retaining the pins. A stator vane in the steam turbine as described. 3. The fixing means comprises a dovetail structure fixing the seal fin piece and the shroud, and a stopper for preventing the seal fin piece from rotating in the circumferential direction. The stationary blade in the steam turbine according to claim 1, wherein