JPH051078U - Gate valve - Google Patents

Abstract

(57) [Abstract] [Purpose] To improve the life of the downstream disc seat in a double disc wedge gate valve. A double disc wedge gate valve in which a wedge is press-fitted between the double discs 5a and 5b to be hermetically sealed and a seal gas having a pressure corresponding to the flow passage pressure is introduced between the discs, and a disc seat 17b on the downstream side in the flow passage direction is provided. Grooves 23 are formed on both sides of the surface of the disk in a direction orthogonal to the disc opening / closing direction, and a seal gas between the disks is introduced into the groove 23 through an introduction passage 24 to reduce the surface pressure of the two sides, which are severely worn, to reduce the life. To improve.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gate valve, and more particularly to a double disc wedge gate valve in which a wedge is press-fitted between double discs to close the double disc.

[0002]

[Prior Art]

 The double disc wedge gate valve has a great feature as a gate valve that can maintain a highly reliable sealed state for a long time even if it is used frequently.In addition, the double disc wedge gate valve has a flow path inside the body, around the body seat and between the double discs. It is also known that a seal gas at a pressure slightly higher than the pressure is introduced to completely prevent leakage of fluid in the flow path.

Since the surfaces of the body sheet and the disc sheet are in sliding contact with each other when the disc is opened and closed, wear-resistant metal is applied.

[0004]

[Problems to be solved by the device]

 However, when the disc is opened and closed with the disc pressing force released by the wedge, the differential pressure between the seal gas pressure and the downstream flow channel pressure is large in the disc on the downstream side in the flow direction. As shown in FIG. 6, the disc moves in a state where the surface of the disc sheet 31 is strongly pressed against the surface of the body sheet. The discs 31a slide against each other for a long distance until the discs are fully opened, so that the discs may be abraded and may be scratched and leak as shown by the arrow. Therefore, the disc sheet on the downstream side must be replaced frequently. There was a problem.

The present invention has been made in view of the above conventional problems, and an object of the present invention is to provide a gate valve in which the life of the disk seat on the downstream side is extended.

[0006]

[Means for Solving the Problems]

 The present invention is a gate valve in which a wedge is press-fitted between double discs to seal and a seal gas having a pressure corresponding to the flow passage pressure is introduced between the discs. It is characterized in that grooves are formed on both sides in a direction orthogonal to the opening / closing movement direction of the disk in, and an introduction passage for introducing the seal gas between the disks is provided in this groove.

[0007]

[Action]

 According to the configuration of the present invention, the sealing gas between the disks is introduced into the grooves formed on both sides of the disk sheet surface on the downstream side in the flow path direction in the direction orthogonal to the opening / closing movement direction of the disk. The surface pressure on both sides of the seat surface is reduced, and as a result, the wear of this part when the valve is opened can be reduced, the leakage due to scratches can be suppressed, and the life of the disc seat can be extended accordingly.

[0008]

【Example】

 Hereinafter, a gate valve according to an embodiment of the present invention will be described with reference to FIGS. 1 to 3, reference numeral 1 denotes a double disc wedge gate valve, in which an inflow pipe portion 3 is formed on one end side in the axial direction of a body 2 and an outflow pipe portion 4 is formed on the other end side thereof, and an intermediate portion therebetween. A tapered gate portion 6 into which the double disks 5a and 5b are fitted is formed in the portion, and a bonnet portion 7 is formed so as to project upward. The upper opening of the bonnet portion 7 is closed by a bonnet cover 8. Ring-shaped body sheets 9a and 9b are detachably attached to the surfaces of the gate portion 6 that face each other in the axial direction, and the upper end communicates with the seal gas space 10 in the bonnet portion 7 on the outer periphery thereof. An arcuate space 11 is formed.

Tapered pressure receiving surfaces 12a and 12b are provided on the opposing surfaces of the central portions of the double disks 5a and 5b, and a wedge 13 is interposed therebetween. The upper end surface of the wedge 13 is engaged with the lower end of the stem shaft 14 arranged so as to penetrate the bonnet portion 7. A large diameter portion 14a is provided at a lower end portion of the stem shaft 14, and a shoulder portion of the large diameter portion 14a is configured to engage with a downward step surface 15 formed on the double discs 5a and 5b via a ring 16. Disc sheets 17a and 17b are detachably attached to the outer surfaces of the double discs 5a and 5b so as to face the body sheets 9a and 9b. A wear resistant heap 18 is applied to the surfaces of the body sheets 9a and 9b and the disc sheets 17a and 1b.

In FIG. 1, 19 is a gland packing provided in a portion where the stem shaft 14 penetrates the bonnet cover 8, and 20 is a seal gas introduction port for introducing the seal gas into the seal gas space 10 inside the bonnet portion 7. Is. Further, in FIG. 2, 25 is a grease inlet.

An arcuate space 11 is opened downward at the lower end of the body 2, and a stopper 21 with which the lower ends of the double disks 5a, 5b abut is inserted. The stopper 21 is held by a bottom cover 22 that hermetically closes the opening.

4 and 5, arcuate grooves 23 are formed on both sides in the direction orthogonal to the opening / closing movement direction of the disks 5a and 5b on the surface of the disk sheet 17b on the downstream side in the flow path direction. Introducing passages 24 for introducing the seal gas between the disks 5a and 5b are provided at both ends and an intermediate portion of each groove 23.

In the above structure, since the large diameter portion 14a at the lower end of the stem shaft 14 and the downward step surface 15 of the double disks 5a, 5b are engaged with each other via the ring 16, the stem shaft 14 is moved up and down. Along with this, the double discs 5a, 5b move up and down, and the gate portion 6 between the inflow pipe portion 3 and the outflow pipe portion 4 is opened and closed. When the stem shaft 14 is further pressed while the lower ends of the double discs 5a and 5b are in contact with the stopper 21, the wedge 13 is pushed down, and the pressure receiving surfaces 12a and 12b at the central portions of the discs 5a and 5b are pushed outward. Then, the disc sheets 17a and 17b of the discs 5a and 5b are strongly pressed against the body sheets 9a and 9b to be hermetically sealed.

Further, a seal gas having a pressure slightly higher than the flow path pressure is supplied to the seal gas space 10, and the seal gas is provided between the arcuate space 11 around the gate portion 6 and the double disks 5 a, 5 b. Since it is introduced, it is possible to completely prevent the fluid in the flow path from leaking from the valve to the outside.

In this valve-closed state, the seal gas between the disks 5a and 5b is introduced through the introduction passage 24 into the grooves 23 formed on both sides of the disk seat 17b of the downstream disk 5b, so Even if the pressure difference between the seal gas pressure and the downstream flow passage pressure in the disc 5b on the downstream side in the road direction is large, the surface pressure between both sides of the disc sheet 17b and the body sheet 9b is low. As a result, when the valve is opened, even if both sides of the disc seat 17b in the direction orthogonal to the opening / closing movement direction of the disc are in sliding contact with the body sheet 9b for a long distance until the disc is fully opened, the surface pressure is small. The occurrence of abrasion and scratches can be suppressed, the leak due to the occurrence of scratches can be suppressed, and the life of the disc sheet 17b can be extended accordingly.

In the above embodiment, the double disc wedge valve 1 is provided in the horizontal flow passage, but the vertical passage is provided so that the discs 5a and 5b can be opened and closed in the horizontal direction. Needless to say, you can.

[0017]

[Effect of the device]

 According to the present invention, as described above, the seal gas between the disks is introduced into the grooves formed on both sides of the disk sheet surface on the downstream side in the flow path direction in the direction orthogonal to the opening / closing movement direction of the disk. As a result, the surface pressure on both sides of the disc seat is reduced, and as a result, the wear of this part when the valve is opened can be reduced, and the leakage due to scratches can be suppressed, which increases the life of the disc seat. It has the effect of being long.

[Brief description of drawings]

FIG. 1 is a vertical sectional view of a double disc wedge valve according to an embodiment of the present invention.

FIG. 2 is a partial cross-sectional plan view of a gate portion.

FIG. 3 is an enlarged vertical sectional view of a wedge arrangement portion.

FIG. 4 is a detailed enlarged cross-sectional plan view of a main part.

FIG. 5 is a front view of a downstream disc sheet.

FIG. 6 is a diagram illustrating a problem of a conventional disc sheet on the downstream side.

[Explanation of symbols]

 1 Double Disc Wedge Valve 5a Disc 5b Disc 13 Wedge 17b Downstream Disc Seat 23 Groove 24 Introduction Passage

Claims (1)

[Claims for utility model registration] 1. A gate valve in which a wedge is press-fitted between the double disks to seal and a seal gas having a pressure corresponding to the flow path pressure is introduced between the disks. A gate valve, characterized in that grooves are formed on both sides of a surface of a disk sheet on the downstream side in the direction perpendicular to the opening / closing movement direction of the disk, and an introducing passage for introducing a seal gas between the disks is provided in the groove.