JPH10196803A - Butterfly valve - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent a catalyst from depositing in recesses defined between the back seats and bleed bushing of a butterfly valve. SOLUTION: A butterfly valve involves, in its valve casing 1, a valve element 2 pivotally supported on a valve stem 3, back seats 4 projecting from the inner periphery of the valve casing 1 so as to receive the peripheral portions 2a of the valve element 2, a bleed bushing disposed between the bearing cylinder 1a of the valve casing 1 and the valve stem 3 so as to butt or abut against the end faces 4a of the back seats 4 at its outer periphery, and purge gas supply passages 6 passing through the bearing cylinder 1a and a bushing 20 up to a clearance gap α defined between the bleed bushing 5 and the valve stem 3. The bearing cylinder 1a is formed with purge gas passages 13 which branch off from the purge gas supply passages 6 and open on recesses 11 defined between the back seats 4 and the bleed bushing 5.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a butterfly valve interposed in a flow path for flowing a fluid such as a high-temperature gas containing dust such as a catalyst.

[0002]

2. Description of the Related Art FIGS. 7 and 8 show an example of a butterfly valve interposed in a flow path for flowing a high-temperature gas containing a catalyst. This is because the valve body 2 is rotatably disposed via the valve rod 3 in the valve box 1 through which the high-temperature gas flows in the direction of the arrow a, and faces the outer peripheral portion 2 a of the valve body 2. A backsheet 4 is protruded from the peripheral surface, and the outer peripheral surface of a bleed bushing 5 inserted between the bearing cylinder 1a of the valve box 1 and the valve shaft 3 comes into contact with or approaches the end face 4a of the backsheet 4, and the bearing cylinder A purge gas supply path 6 penetrating through the bush 20 and the bleed bushing 5 and communicating with the gap α between the valve stem 3 is formed. A purge gas supply pipe 7 is connected to each of the purge gas supply paths 6, and the bleed bushing is formed. A purge gas hole 8 communicating with the inside of the valve box 1 is provided through an end of the valve box 5.
Reference numeral 9 denotes a spring inserted into the bushing 1a, which is pressed by a pressing member 10 fixed to an end of the bushing 1a to press the bleed bushing 5 toward the valve body 2.

In the above configuration, each purge gas supply pipe 7
To supply the purge gas from the purge gas hole 8 into the valve box 1 through the purge gas supply path 6 and the gap α.
The catalyst, dust and the like in the high-temperature gas flowing through the valve box 1 are prevented from entering the bearing cylinder. In this state, the valve stem 3
Is rotated in the forward and reverse directions to open the valve body 2 (FIG. 8).
A position) or a closed state (the B position in FIG. 8).

[0004]

In the above-mentioned conventional configuration,
As shown in FIG. 8, the catalyst D contained in the high-temperature gas easily adheres and accumulates in the concave portion 11 between the back sheet 4 and the bleed bushing 5, whereby the valve body 2 is closed (position B in FIG. 8). When the valve body 2 and the back seat 4
Therefore, the valve body 2 cannot be fully closed with the catalyst D interposed therebetween, which may hinder plant operation.

SUMMARY OF THE INVENTION In view of the above problems, an object of the present invention is to provide a butterfly valve which prevents dust such as a catalyst from adhering and accumulating in a concave portion between a back sheet and a bleed bushing.

[0006]

In order to achieve the above object, according to the first aspect of the present invention, there is provided a valve body in a valve box interposed in a flow path for flowing a fluid such as a high-temperature gas containing dust. The valve seat is rotatably disposed, and a back sheet is protruded from an inner peripheral surface of the valve box so as to face an outer peripheral portion of the valve body, and is inserted between a bearing cylinder of the valve box and a valve shaft. A butterfly valve having a purge gas supply passage formed such that an outer peripheral surface of a bleed bushing abuts or approaches an end surface of the backsheet, penetrates the bushing and the bush, and communicates with a gap between the bleed bushing and a valve rod. , A purge gas passage communicating with the purge gas supply passage and opening to face a concave portion between the back sheet and the bleed bushing is formed in the bearing cylinder.

In the above configuration, by supplying the purge gas from the purge gas supply passage to the gap between the bleed bushing and the valve rod, the catalyst, dust and the like in the high-temperature gas flowing through the valve case pass through the bearing cylinder. By injecting the purge gas from the purge gas supply passage through the purge gas passage toward the concave portion between the back sheet and the bleed bushing, dust such as a catalyst adheres and accumulates in the concave portion. Can not be.

In this case, the purge gas is ejected from the purge gas passage toward the concave portion between the back sheet and the bleed bushing so that dust such as the catalyst does not adhere to and accumulate in the concave portion. Can be fully closed. In addition, since the purge gas path only needs to be formed in the bearing cylinder of the existing butterfly valve, the configuration is simple, the production cost is hardly increased, and the cost is low.

According to a second aspect of the present invention, a valve body is rotatably disposed via a valve rod in a valve box interposed in a flow path through which a fluid such as a high-temperature gas containing dust flows. A back seat protrudes from the inner peripheral surface of the valve box so as to face the outer peripheral portion of the valve case. The outer peripheral surface of the bleed bushing inserted between the bearing cylinder of the valve box and the valve shaft contacts the end surface of the back seat. A butterfly valve having a purge gas supply passage formed in contact with or approaching therethrough and penetrating through the bushing and the bush and communicating with the gap between the bleed bushing and the valve rod. A purge gas hole is provided to communicate with a gap between the backsheet and the bleed bushing and open through the recess between the backsheet and the bleed bushing.

According to the above construction, similarly to the first aspect of the invention, by supplying the purge gas to the gap between the bleed bushing and the valve stem, the catalyst and the dust in the high-temperature gas flowing through the valve box are supplied. And the like can be prevented from penetrating through the inside of the bearing cylinder, and the purge gas is blown out from the purge gas hole toward the concave portion between the back sheet and the bleed bushing, so that dust such as catalyst adheres and accumulates in the concave portion. Since it is not performed, the valve body can be completely closed. Further, since it is only necessary to form a purge gas hole in the bleed bushing of the existing butterfly valve, the structure is simple, the production cost is hardly increased, and the cost is low.

[0011]

Embodiments of the present invention will be described below with reference to the drawings. FIGS. 1 to 3 show a butterfly valve according to an embodiment of the present invention.
Further, a purge gas passage 13 communicating with the purge gas supply passage 6 and opening to face the concave portion 11 between the back sheet 4 and the bleed bushing 5 is formed. Since the configuration other than the above is almost the same as the conventional example shown in FIGS.

In the above configuration, each purge gas supply pipe 7
By supplying the purge gas into the valve box 1 from the purge gas hole 8 through the purge gas supply path 6 and the gap α from the inside, the catalyst, dust and the like in the high-temperature gas flowing through the valve box 1 do not enter the bearing cylinder. You can do so.

The back sheet 4 passes through the purge gas passage 13.
The purge gas is jetted toward the concave portion 11 between the bleed bushing 5 and the catalyst D.
Is prevented from adhering and accumulating, so that the valve body 2 can be completely closed (the position B in FIG. 2).

In this case, the bearing cylinder 1 of the existing butterfly valve is used.
Since it is only necessary to form the purge gas passage 13 in a, the construction is simple, the production cost is hardly increased, and the cost is low.
4 to 6 show a butterfly valve according to another embodiment of the present invention, in which an end of a bleed bushing 5 communicates with a gap α between the bleed bushing 5 and the valve stem 3. In addition, a purge gas hole 14 that opens to face the concave portion 11 between the back sheet 4 and the bleed bushing 5 is provided therethrough.

According to the above configuration, as in the first embodiment shown in FIGS. 1 to 3, the purge gas is supplied to the gap α between the bleed bushing 5 and the valve rod 3 so that the valve box 1
The catalyst, dust and the like in the high-temperature gas flowing through the inside can be prevented from entering the bearing cylinder, and the purge gas is ejected from the purge gas hole 14 toward the concave portion 11 between the back sheet 4 and the bleed bushing 5. Since the catalyst D is prevented from adhering and accumulating in the concave portion 11, the valve body 2 can be completely closed (the position B in FIG. 5) without fail.
Note that the purge gas hole 8 may be omitted depending on the opening degree of the valve that is always used.

In this case, it is only necessary to form the purge gas hole 14 in the bleed bushing 5 of the existing butterfly valve, so that the construction is simple, the production cost is hardly increased, and it is economical.

By combining the above two embodiments, the purge gas passage 13 may be formed in the bearing cylinder 1a and the purge gas hole 14 may be formed in the bleed bushing 5. As a result, the catalyst D can be more reliably prevented from adhering and accumulating in the concave portion 11 between the back sheet 4 and the bleed bushing 5.

[0018]

According to the first aspect of the present invention, the purge gas is ejected from the purge gas passage toward the concave portion between the back sheet and the bleed bushing so that dust such as the catalyst does not adhere to and accumulate in the concave portion. Thus, the valve body can be completely closed without fail. In addition, since the purge gas path only needs to be formed in the bearing cylinder of the existing butterfly valve, the configuration is simple, the production cost is hardly increased, and the cost is low.

According to the second aspect of the present invention, the purge gas is ejected from the purge gas hole toward the concave portion between the back sheet and the bleed bushing so that dust such as a catalyst does not adhere to and accumulate in the concave portion. The valve can be completely closed without fail. Further, since it is sufficient to form only the purge gas hole in the bleed bushing of the existing butterfly valve, the structure is simple, the production cost is hardly increased, and it is economical.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of a butterfly valve according to an embodiment of the present invention.

FIG. 2 is a view as viewed in the direction of arrows AA in FIG. 1;

FIG. 3 is a perspective view of the main part.

FIG. 4 is a longitudinal sectional view of a butterfly valve according to another embodiment of the present invention.

FIG. 5 is a view taken in the direction of arrows BB in FIG. 4;

FIG. 6 is a perspective view of the main part.

FIG. 7 is a half sectional front view of the entire butterfly valve showing a conventional example.

8 is a view as viewed in the direction of arrows CC in FIG. 7;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Valve box 1a Bearing cylinder 2 Valve body 2a Peripheral part of valve body 3 Valve rod 4 Back seat 4a End face of back sheet 5 Bleed bushing 6 Purge gas supply path 11 Depression between back sheet and bleed bushing 13 Purge gas path 14 Purge gas hole 20 Bush D Catalyst (dust) α Gap between bleed bushing and valve stem

Claims (2)

[Claims] A valve body is rotatably disposed via a valve rod in a valve box interposed in a flow path for flowing a fluid such as a high-temperature gas containing dust, and faces a peripheral portion of the valve body. A backsheet is projected from an inner peripheral surface of the valve box, and an outer peripheral surface of a bleed bushing inserted between a bushing of the valve box and a valve shaft abuts or approaches an end surface of the backsheet. In a butterfly valve formed with a purge gas supply passage penetrating through a bearing cylinder and a bush and communicating with a gap between the bleed bushing and a valve rod, the bearing cylinder communicates with the purge gas supply passage with the back seat. A butterfly valve, wherein a purge gas passage that opens to face an upstream recess between the bleed bushing and the bleed bushing is formed. 2. A valve body is rotatably disposed via a valve rod in a valve box interposed in a flow path through which a fluid such as a high-temperature gas containing dust flows, and faces a peripheral portion of the valve body. A backsheet is projected from an inner peripheral surface of the valve box, and an outer peripheral surface of a bleed bushing inserted between a bushing of the valve box and a valve shaft abuts or approaches an end surface of the backsheet. In a butterfly valve formed with a purge gas supply passage penetrating through a bearing cylinder and a bush and communicating with a gap between the bleed bushing and the valve rod, an end of the bleed bushing is provided between the bleed bushing and the valve rod. A purge gas hole which is opened to face the downstream recess between the back seat and the bleed bushing so as to communicate with the gap of the butterfly valve.