JP2000104854A - Butterfly valve - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a butterfly valve excellent in heat resistance. SOLUTION: A first to second bearing holes 8, 9 are passed through a housing side wall 7 forming a fluid passage 6. A first to second bushes 10, 11 are press fitted into the first to second bearing holes 8, 9. A drive shaft 13 of a valve main body 15 is passed and inserted through/into the first bush 10. At the outside of the first bush 10, a labyrinth seal 18 formed by engaging a first seal plate and a second seal plate is disposed. A housing 5, the first bush 10, the second bush 11 and the first seal plate are formed by ferritic stainless steel. The valve main body 15 and the second plate are formed by austenitic stainless steel.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a butterfly valve suitable for controlling the flow of a high-temperature fluid.

[0002]

2. Description of the Related Art Conventionally, a bearing hole is formed in a side wall of a housing forming a fluid passage, a bush is pressed into the bearing hole, and a shaft of a valve body for opening and closing the fluid passage is inserted through the bush. A labyrinth seal comprising a ring-shaped first seal plate fitted to the bearing hole and a ring-shaped second seal plate fitted to the shaft outside the bush, wherein the two seal plates are engaged with each other. Is known (for example, Japanese Utility Model Laid-Open No. 6-607).
No. 40 publication).

[0003]

However, since the first seal plate and the second seal plate forming the labyrinth seal of the conventional butterfly valve are formed of austenitic stainless steel, high-temperature fluid flows through the fluid passage. Then, there is a problem that the first and second seal plates are heated, the first seal plate and the second seal plate are seized, and the valve body does not rotate. Therefore,
The present invention has been made to solve such a problem, and an object of the present invention is to provide a butterfly valve in which rotation of a valve body is not hindered even when a high-temperature fluid flows in a fluid passage.

[0004]

According to the present invention, a bearing hole is provided through a side wall of a housing forming a fluid passage, a bush is pressed into the bearing hole, and a shaft of a valve body for opening and closing the fluid passage is provided. A first ring-shaped seal plate fitted to the bearing hole and a second ring-shaped seal plate fitted to the shaft; Wherein the housing, the bush, and the first seal plate are formed of ferritic stainless steel, and the shaft and the second seal plate are austenitic stainless steel. It is characterized by being formed from steel.

In the butterfly valve having the above-described structure, when a high-temperature fluid flows through the fluid passage, the housing formed of ferritic stainless steel, the bush, and the first seal plate are baked together and integrated, and the housing and the bush are connected to each other. The airtightness between the housing and the first seal plate is increased, and the shaft made of austenitic stainless steel and the second seal plate are baked together and integrated, and the shaft and the first seal plate are integrated. The airtightness with the second seal plate is increased. On the other hand, the housing, the bush, and the first seal plate formed of ferritic stainless steel, and the shaft and the second seal plate formed of austenitic stainless steel are less likely to seize each other.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to FIGS. As shown in FIG. 1, a butterfly valve 4 functioning as an exhaust brake valve is provided in the middle of an exhaust pipe 3 connected to an engine 2 via an exhaust manifold 1. As shown in FIG. 2, a cylindrical fluid passage 6 penetrates the housing 5 of the butterfly valve 4, and a fluid passage 6 is formed in a housing side wall 7 forming the fluid passage 6.
A first bearing hole 8 and a second bearing hole 9 which are orthogonal to each other and face each other are provided through. A first cylindrical bush 10 is press-fitted into the first bearing hole 8, and a bottomed cylindrical second bush 11 is press-fitted into the second bearing hole 9.

In the fluid passage 6, a disc-shaped valve body 12 having an outer diameter slightly smaller than the inner diameter of the fluid passage 6 is provided.
A drive shaft 13 fixedly provided on the first bearing hole 8 side of the valve body 12 is inserted through the first bush 10, and a driven shaft 14 fixedly provided on the second bearing hole 9 side of the valve body 12 is connected to the second bushing. 11, a valve body 15, a drive shaft 13, and a driven shaft 14
Are formed. The drive shaft 13 is connected to a valve drive device (not shown) provided outside the housing 5.
A hemispherical portion 16 is formed at the tip of the driven shaft 14, and the tip of the hemispherical portion 16 contacts the bottom surface 17 of the second bush 11.

A labyrinth seal 18 is provided outside the first bush 10 (left side in FIG. 2), and a flange fastened to the housing 5 by bolts 19 outside the labyrinth seal 18 (left side in FIG. 2). First sealing member 2
0 is provided. Outside the second bush 11 (the right side in FIG. 2), a disc-shaped second seal member 22 fastened to the housing 5 by a bolt 21 is provided.

As shown in FIG. 3, the labyrinth seal 18
Consists of three ring-shaped first seal plates 23 fitted in the first bearing hole 8 of the housing 5 and two ring-shaped second seal plates 24 fitted on the drive shaft 13 and are adjacent to each other. The second seal plate 24 is arranged between the first seal plates 23, and the first seal plate 23 and the second seal plate 24 are engaged.

In the butterfly valve 4 having the above configuration, the housing 5, the first bush 10, the second bush 11, the first seal member 20, and the second seal member 22
The first seal plate 23 and the first seal plate 23 are formed of heat-resistant ferritic stainless steel having the same composition, and the valve body 15 and the second seal plate 24 are formed of austenitic stainless steel having the same composition. The housing 5, the first bush 10, and the second bush 1
1, a first seal member 20, a second seal member 22,
The first seal plate 23 does not necessarily need to be formed from a ferritic stainless steel having the same composition, and may be formed from a ferritic stainless steel having a different composition. The valve body 15 and the second seal plate 24 do not necessarily need to be formed of austenitic stainless steel having the same composition, but may be formed of austenitic stainless steel having different compositions.

When the high-temperature exhaust gas flowing out of the engine 2 flows through the fluid passage 6 of the butterfly valve 4, the butterfly valve 4 is heated, and the housing 5, the first bush 10, and the second bush 10 made of ferritic stainless steel are heated. 11, the first seal member 20, the second seal member 22, and the first seal plate 23 seize to each other, and the valve body 1 made of austenitic stainless steel.
5 and the second seal plate 24 are seized to each other, and the sealing performance between the members where the seizure has occurred is improved. On the other hand, since the ferritic stainless steel and the austenitic stainless steel hardly seize each other, the valve body 15
Between the first and second bushings 10, 11 and the valve body 1
The slidability between the first seal member 23 and the first seal member 23 and the slidability between the first seal plate and the second seal plate are maintained, and the valve body 15 rotates favorably in a high-temperature atmosphere.

[0012]

According to the present invention, a bearing hole is provided in a side wall of a housing forming a fluid passage, a bush is pressed into the bearing hole, and a shaft of a valve body for opening and closing the fluid passage is connected to the bush. A first ring-shaped seal plate fitted to the bearing hole and a second ring-shaped seal plate fitted to the shaft are provided on the outside of the bush, and the two seal plates are engaged with each other. In the butterfly valve provided with the above-mentioned labyrinth seal, the housing, the bush, and the first seal plate are formed from ferritic stainless steel, and the shaft and the second seal plate are formed from austenitic stainless steel. In addition, even in a high-temperature atmosphere, seizure of the sliding portion hardly occurs, and the valve body rotates well, so that the valve life is prolonged.

[Brief description of the drawings]

FIG. 1 is a diagram showing an example of a portion to which a butterfly valve of the present invention is applied in an embodiment of the present invention.

FIG. 2 is a sectional view showing a II-II section of FIG. 1;

FIG. 3 is an enlarged sectional view of a main part of FIG. 2;

[Explanation of symbols]

 Reference Signs List 4 butterfly valve 5 housing 7 housing side wall 8, 9 bearing hole 10 first bush 11 second bush 15 valve body 13 drive shaft 14 driven shaft 18 labyrinth seal 23 first seal plate 24 second seal plate

Claims (1)

[Claims] 1. A bearing hole is provided in a side wall of a housing forming a fluid passage, a bush is pressed into the bearing hole, and a shaft of a valve body for opening and closing the fluid passage is inserted through the bush. A labyrinth seal including a ring-shaped first seal plate fitted to the bearing hole and a ring-shaped second seal plate fitted to the shaft, and the two seal plates are engaged outside the bush. The butterfly valve, wherein the housing, the bush, and the first seal plate are formed of ferritic stainless steel, and the shaft and the second seal plate are formed of austenitic stainless steel. .