JP3040662B2 - Vibration control vane structure of steam turbine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a damping vane structure for a steam turbine.

[0002]

2. Description of the Related Art In a conventional steam turbine vane, as shown in a perspective view of FIG. 4 and a partially enlarged view of FIG. 5, outer ends of individual vanes 2 are directly welded to a blade root ring 3 at a welding portion 4. In addition, a structure in which the inner ends are directly welded to the shroud 1 is adopted. As described above, since each of the stationary blades is completely welded and fixed to the blade root ring 3 and the shroud 1 at the outer end and the inner end, the damping is extremely small in terms of structure.

[0003]

As described above, the conventional vane structure of a steam turbine employs a welded structure, so that structural damping is very small, and thus has a frequency component that is an integral multiple of the rotor speed. When it resonates with the excitation force, the vibration stress increases, which may cause blade damage. Also,
Since the structural damping is small, self-excited vibration such as random vibration or flutter due to turbulence of steam is likely to occur.

The present invention has been proposed in view of such circumstances, and has a long service life which prevents the occurrence of resonance, random vibration, self-excited vibration, and the like, and reduces the vibration stress to prevent the occurrence of damage. An object of the present invention is to provide a damping vane structure for a steam turbine.

[0005]

For this purpose, the present invention connects the opposite ends of the shrouds of adjacent blade groups to each other with connecting plates and rivets, and utilizes friction generated between the shrouds and the connecting plates. To obtain an effect of damping vibration.

[0006]

According to such a structure, as shown in FIGS. 1 to 3, when the opposing ends of the adjacent shrouds are connected to each other by using the rivets 7 at the connection plate 6, when resonance occurs, Since relative slippage occurs between the shroud, the connection plate, and the rivet, the damping effect increases, and the growth of resonance stress can be suppressed. In addition, since the damping effect is increased, random vibration or self-excited vibration such as flutter caused by the turbulence of steam is less likely to occur, and reliability can be improved.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to the drawings, an embodiment of the present invention will be described. FIG. 1 is a partial perspective view, FIG. 2 is a cross-sectional view showing a connecting portion between a shroud and a connecting plate in FIG. 1, and FIG. It is an exploded perspective view showing a part.

In the upper figure, the same reference numerals as those in FIGS. 4 and 5 denote the same members as those in FIGS. 4 and 5, respectively. In this embodiment, a pair of right and left parts is provided at both ends of the shroud 1 as shown in FIG. Are provided, and both ends of the rectangular connecting plate 6 are inserted into the grooves 5, and the both ends are fixed to the corresponding shrouds 1 and rivets 7, respectively.

In this embodiment, the connection plates 6 are inserted on both the inner and outer surfaces of the shroud 1, respectively. However, the connection plates may be inserted on only one side.

[0010]

According to such a structure, grooves are provided at both ends of the shroud, the connecting plate is inserted into the grooves, and the shroud and the connecting plate are riveted to thereby increase the structural damping of the stationary blade. can do. When the structural damping increases, vibrations are less likely to be generated in the stationary blade, and thus the reliability of the stationary blade is improved.

In short, according to the present invention, the opposing ends of the shrouds of the adjacent blade groups are connected to each other by connecting plates and rivets, and a damping effect on vibration is obtained by utilizing the friction generated between each shroud and the connecting plate. To obtain a long-life steam turbine damping vane structure of a steam turbine that prevents the occurrence of resonance, random vibration, self-excited vibration, etc., and reduces the vibration stress to prevent the occurrence of damage. Therefore, the present invention is extremely useful in industry.

[Brief description of the drawings]

FIG. 1 is a perspective view of a stationary blade showing one embodiment of the present invention.

FIG. 2 is a partial cross-sectional front view showing a structure of a shroud and a connecting plate of the stationary blade of FIG. 1;

FIG. 3 is an exploded perspective view showing a part III in FIG. 2;

FIG. 4 is a perspective view showing a stationary blade of a conventional steam turbine.

FIG. 5 is a partially enlarged view of the stationary blade of FIG. 4;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Shroud 2 Stator blade 3 Blade root ring 4 Welded part 5 Shroud groove 6 Connection plate 7 Rivet

Claims (1)

(57) [Claims] 1. The opposed ends of shrouds of adjacent blade groups are connected to each other by connecting plates and rivets, and a damping effect on vibration is obtained by utilizing friction generated between each shroud and the connecting plate. A damping vane structure for a steam turbine, characterized in that: