JP2000074228A - Seat structure of butterfly valve - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a seat structure of a butterfly valve which can prevent powder from being built up on a valve housing seat so as to always ensure full-close operation. SOLUTION: A plurality of purge holes 18 radially extending through a valve body seat 15, are formed, at suitable angular intervals, a purge gas feed passage 21 is formed in a valve rod 14, being axially extended through the valve rod 14, and a gas passage communicating the purge gas feed passage 21 with the purge holes 18 is formed in a valve element 13.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a butterfly valve seat structure interposed in a pipe for flowing a fluid such as a high-temperature gas containing powder.

[0002]

2. Description of the Related Art FIG. 3 shows an example of a butterfly valve of this type. The valve body 1 is inserted into a valve box 1 interposed in a conduit through which a fluid such as a high-temperature gas containing powder flows, a valve body 3 for opening and closing a flow path 2 of the valve box 1, and a boss portion 4 of the valve body 3. ,
And a valve stem 5 for holding the valve body 3 rotatably about the axis.

The valve body 3 has a ring-shaped valve body sheet 6 on the periphery thereof, and a valve box sheet 7 which is in contact with the valve body sheet 6 on the inner peripheral surface of the valve box 1.

[0004]

In the conventional structure described above, in the fully closed state, the valve body sheet 6 of the valve body 3 abuts on the valve box sheet 7 of the valve box 1 and shuts off the flow path 2 of the valve box 1. I do. In the fully opened state, the valve element 3 rotates around the axis of the valve rod 5, and the valve element 3
Becomes parallel to the flow of the controlled fluid, and opens the flow path 2 of the valve box 1. At this time, if the controlled fluid flowing through the flow path 2 of the valve box 1 contains powder, the powder 8 accumulates on the valve box sheet 7, and when the powder 8 closes the valve body 3, the valve is closed. In some cases, the valve body 3 is caught between the body sheet 6 and the valve box sheet 7 to hinder the fully closing operation of the valve body 3 and cause leakage.

An object of the present invention is to solve the above-mentioned problems, and an object of the present invention is to provide a seat structure of a butterfly valve which can prevent powder from accumulating on a valve box sheet and can always secure a completely closed operation. .

[0006]

In order to solve the above-mentioned problems, a seat structure of a butterfly valve according to the present invention comprises a valve box having a valve body for opening and closing a flow path in a valve box, which is turned around an axis of a valve stem. Movably provided, a ring-shaped valve body sheet is provided on the periphery of the valve body,
In a butterfly valve provided with a valve box sheet abutting on a valve body sheet on the inner peripheral surface of a valve box, a plurality of purge holes radially penetrating through the valve body sheet are provided radially at appropriate intervals in a circumferential direction, and the valve A purge gas supply passage is provided in the rod in the axial direction, and a gas flow passage communicating the purge gas supply passage and the purge hole is provided in the valve body.

With the above arrangement, at the time when the valve element is opened to a small degree during the closing operation of the valve element, the purge gas is supplied into the valve element through the purge gas supply path, and the purge gas is injected from the purge hole through the gas flow path. The powder that accumulates on the valve box sheet is removed.

[0008]

Embodiments of the present invention will be described below with reference to the drawings. 1 and 2, the butterfly valve 11 has a valve box 12 interposed in a pipe (not shown) through which a fluid such as a high-temperature gas containing powder flows. A valve body 13 that opens and closes a path is rotatably provided around an axis of a valve rod 14.

The valve body 13 has a hollow structure in which outer shells 16 are arranged on the front and back of a ring-shaped valve body sheet 15 provided on the peripheral edge, and a boss 17 fitted to the valve stem 14 is provided at the center. Is arranged. The valve seat 15 has a plurality of radially penetrating purge holes 18 radially provided at appropriate intervals in the circumferential direction. The boss 17 has a plurality of radially penetrating vent holes 19 in the circumferential direction. It is provided radially at intervals,
A gas flow passage communicating between the purge hole 18 and the inside of the boss 17 is formed by the hollow portion 20 and the ventilation hole 19 formed between the outer shell material 16 on the front and back sides.

The valve stem 14 has a purge gas supply passage 21 formed in the axial direction. The purge gas supply passage 21 has a base end opening at the distal end face of the valve stem 14 and a tip end inside the boss 17.
4 is open on the outer peripheral surface so as to face the ventilation hole 19. A valve box sheet 22 is provided on the inner peripheral surface of the valve box 12 to be in contact with the valve body sheet 15.

The operation of the above configuration will be described below. The opening and closing operation of the valve element 13 is performed by rotating the valve rod 14 about the axis, and the valve element sheet 15 is brought into contact with the valve box sheet 22 in the fully closed position, and the valve element 13 is controlled by the flow of the controlled fluid. This is done over the full open position which is parallel.

When the valve body 13 is opened, the valve box sheet 22 is exposed to the controlled fluid, and the powder contained in the controlled fluid is deposited on the inner peripheral surfaces of the valve box sheet 22 and the valve box 12. For this reason, at the time of closing operation of the valve body 13, when the valve body 13 becomes a small opening degree, the purge gas is supplied to the inside of the valve body 13 through the purge gas supply passage 21, and the purge gas is supplied through the vent hole 19 and the hollow portion 20. A purge gas is injected from 18 to remove powder deposited on the inner peripheral surfaces of the valve box sheet 22 and the valve box 12 by blowing away the purge gas.

[0013]

As described above, according to the present invention, when the valve body is closed, the purge gas is injected from the purge hole of the valve body sheet toward the valve box sheet and the inner peripheral surface of the valve box. The powder that accumulates can be removed, and the accumulation of powder on the valve box sheet can be prevented, so that a reliable full closing operation can always be ensured.

[Brief description of the drawings]

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

FIG. 2 is a cross-sectional view of the butterfly valve according to the embodiment.

FIG. 3 is a sectional view showing a conventional butterfly valve.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 11 Butterfly valve 12 Valve box 13 Valve body 14 Valve rod 15 Valve body sheet 16 Outer shell material 17 Boss 18 Purge hole 19 Vent hole 20 Hollow part 21 Purge gas supply path 22 Valve box sheet

Claims (1)

[Claims] 1. A valve body for opening and closing a flow passage in a valve box is provided on a valve box so as to be rotatable around an axis of a valve stem, and a ring-shaped valve body sheet is provided on a peripheral portion of the valve body. In a butterfly valve having an inner peripheral surface provided with a valve box sheet that abuts on a valve body sheet, a plurality of radially penetrating purge holes are radially provided in the valve body sheet at appropriate intervals in a circumferential direction, and the valve stem is provided with a shaft. A butterfly valve seat structure, characterized in that a purge gas supply passage is provided by being bored in the center direction, and a gas flow passage communicating the purge gas supply passage and the purge hole is provided in the valve body.