JP2001221364A - Soft seal gate valve - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a soft seal gate valve capable of restraining the cavitation damage from affecting the downstream side from a valve element by restraining generation of cavitation by evenly correcting the flow distribution in the intermediate opening of the valve element. SOLUTION: Four guide grooves 15A, 15B, 15C and 15D spread from the central part in the width direction of the valve element 1 towards both right and left sides in the width direction and also downward of the valve element 1 into a fan shape are provided on a raised rubber lining layer 13 facing an upstream side opening 10 of a valve casing 2 in the valve element 1 composed of a core metal 1A and the rubber lining layer 13 for coating the front surface of the core metal 1A. In the intermediate opening of the valve element 1, water interfering with the valve element 1 is evenly dispersed and allowed to flow diagonally right down, diagonally left down and toward the central part lower end in the width direction as indicated by arrows by the guiding action of the guide grooves 15A, 15B, 15C and 15D.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a soft-seal gate valve used as a water-supply gate valve, and more particularly to a soft-seal gate valve having a function of avoiding the influence of cavitation which is concerned at an early stage of valve opening.

[0002]

2. Description of the Related Art As shown in FIGS. 5 and 6, for example, a soft seal gate valve frequently used in a water supply piping system of a water supply system has an axis C2 perpendicular to an axis C1 of a valve box 2 as shown in FIG. And the axis C of the valve stem 3
It is housed in the valve box 2 so as to be movable up and down (movable forward and backward) in two directions. The valve stem 3 is provided with a male screw portion 3A, and a female screw piece 4 screwed into the male screw portion 3A is incorporated in the valve body 1. On the other hand, a lid 5 is bolted on the upper part of the valve box 2.
A packing box 7 is fastened to the upper part of the lid 5 by bolts 8. The upper end of the valve stem 3 protrudes upward through a packing box 7 and is covered with a cap 9. In use, the upstream water passage 11 is connected to the upstream opening 10 of the valve box 2 as shown in FIG. 7, and the downstream water passage 1 is connected to the downstream opening (not shown) of the valve box 2.
2 are connected. On the other hand, as shown in FIG.
The structure is such that the surface of the cored bar 1A is entirely covered with a rubber lining layer 13.

[0003] The soft seal gate valve having the above-described structure is generally used.
The valve body 1 is used while being held at a fully open position where the valve body 1 is raised from the fully closed position shown in FIG. 7 to the position shown in FIG. 8 and a fully closed position where the valve body 1 is lowered from this fully open position to the position shown in FIG.

[0004]

However, in the conventional soft-seal gate valve of the prior art, the valve is retracted from the fully closed position shown in FIG. 7 to the fully opened position shown in FIG. 8, for example, the valve shown in FIG. When the opening of the body is at an intermediate opening of about 20% or less, the water in the upstream-side water pipe 11 is mostly obliquely lower right and lower left as shown by arrows due to interference with the valve body 1. And flows down to the downstream side of the valve body 1 through gaps 14A and 14B between the left and right lower ends of the valve body 1 and the bottom left and right sides of the valve box 2, and the widthwise central lower end of the valve body 1 A smaller amount of water flows through the gap 14 between the bottom of the valve box 2 and the center of the bottom surface in the width direction than the gaps 14A and 14B.
It shows the characteristic of flowing down to the downstream side. Therefore, on the downstream side of the valve element 1, as shown in FIG. 10, the flow rate is large on both sides in the width direction as indicated by a solid arrow X1, and is small at the center in the width direction as indicated by a broken arrow X2. A non-uniform flow distribution is shown, and cavitation is caused by such non-uniform flow distribution, and adverse effects such as cavitation erosion are caused by the valve box 2 and the downstream water pipe 12 downstream of the valve body 1. There was a risk of reaching.

Therefore, the present invention suppresses the occurrence of cavitation by uniformly correcting the flow rate distribution at the intermediate opening degree of the valve body, and the adverse effect such as cavitation erosion extends downstream of the valve body. It is an object of the present invention to provide a soft-seal gate valve that can prevent the occurrence of swelling.

In order to achieve the above object, a soft seal gate valve according to the present invention comprises a valve body having a surface covered with an elastic lining layer attached to a valve stem having an axis intersecting the axis of a valve box. , Housed in the valve box movably forward and backward in the axial direction of the valve stem, closing the valve box by forward movement of the valve body,
In a soft seal gate valve configured to open a valve box by retreating a valve body, a flow of a fluid is applied to the elastic material lining layer on a surface of the valve body facing at least an upstream opening of the valve box. A plurality of guide grooves are provided on the left and right sides in the width direction from the center in the width direction of the valve body, and are spread and dispersed in a fan shape in the forward direction of the valve body.

According to the present invention, at the intermediate opening degree of the valve body, the upstream fluid which interferes with the valve body is guided by the plurality of guide grooves to the central portion in the width direction of the valve body and to the left and right in the width direction. The water is evenly distributed on both sides and flows down the valve body.

[0008]

An embodiment of the present invention will be described below with reference to the drawings. The characteristic configuration of the present invention is in the valve body, such as a valve box, a valve stem, a female screw top, a lid, a bolt and a nut, a packing box, a bolt, a cap, an upstream opening, an upstream water pipe, and a downstream water pipe. Since the structure and operation are the same as those of the conventional example, the description of the overlapping structure and operation and the illustration are omitted.

FIG. 1 is a front view of the valve element as viewed from the upstream side in the fluid flow direction, and FIG. 2 is a sectional view of a surface portion along the line AA in FIG. A metal cored bar 1A and a rubber lining layer 13 covering the surface of the metal cored bar 1A, and an upright surface of the valve body 1 facing the upstream opening 10 (see FIG. 5) of the valve box 2. In the rubber lining layer 13, four guide grooves extending in a fan shape from the center in the width direction of the valve body 1 to the left and right sides in the width direction and downward (in the forward direction of the valve body 1). 15A, 15B, 15
C and 15D are provided. These guide grooves 15A, 1
5B, 15C, and 15D are provided on the surface of the cored bar 1A in advance.
Four grooves 16A, 16 fanwise expanding downward
B, 16C, and 16D are provided, and are formed by coating the surface of the cored bar 1A with a rubber lining layer 13 having a predetermined thickness, and the depth of each is set to about 5 mm.

In the case of a soft seal gate valve using the valve element 1 having the above-described structure, an initial stage of retracting the valve element from the fully closed position shown in FIG. 7 to the fully open position shown in FIG. 8, for example, the valve element shown in FIG. In the middle opening where the opening of 1 is within about 20%,
The water in the upstream water pipe 11 that interferes with the valve body 1
Due to the guide action of 5A, 15B, 15C, 15D, the fluid flows evenly toward the lower right, the lower left, and the lower end in the center in the width direction as indicated by arrows, and flows to the lower right and left lower ends of the valve body 1 and the valve box. Clearances 14A and 14B between the left and right sides of the bottom of 2
And it flows down to the downstream side through the gap 14 between the width direction center lower end of the valve body 1 and the bottom surface width direction center of the valve box 2. Therefore, on the downstream side of the valve element 1, as shown by the solid line arrow X1 in FIG. 4, a uniform flow distribution is shown on both sides in the width direction and the center part in the width direction, and the occurrence of cavitation, which has been a concern in the past, is suppressed. By suppressing this, it is possible to prevent adverse effects such as cavitation erosion from reaching the valve box 2 and the downstream water pipe 12 (see FIG. 1) downstream of the valve body 1.

In the above embodiment, the valve body 1 in which the surface of the metal core 1A is covered with the rubber lining layer 13 is described, but the metal core is made of a resin lining layer having high elasticity. It may be a valve element 1 coated on the surface of 1A.

Also, the description has been made of a configuration in which four guide grooves 15A, 15B, 15C, and 15D are provided in the rubber lining layer 13 of the valve body 1 that faces the upstream opening 10 of the valve box 2 on the upright surface. A structure in which the guide grooves 15A, 15B, 15C, and 15D are similarly provided in the rubber lining layer 13 of the valve body 1 facing the opening (not shown) on the downstream side of the valve box 2, that is, the valve body 1 Guide grooves 1 on both front and rear surfaces
The structure provided with 5A, 15B, 15C, and 15D may be sufficient. With such a structure, the occurrence of cavitation when water flows backward is suppressed, and adverse effects such as cavitation erosion are caused by the valve box 2 downstream of the valve body 1.
And it can prevent extending to the upstream side water pipe 11 etc.

Further, four guide grooves 15A, 15B, 1
Although the description has been given of the structure provided with 5C and 15D, the number of guide grooves may be three or five or more.

[0014]

As described above, since the soft seal gate valve of the present invention is constituted, the following special effects can be obtained.

That is, since the flow distribution at the intermediate opening of the valve body is evenly corrected, the occurrence of cavitation, which has been a concern in the past, is suppressed, and adverse effects such as cavitation erosion occur downstream of the valve body. This can be reliably prevented from spreading.

[Brief description of the drawings]

FIG. 1 is a front view of a valve element, which is a characteristic part of the present invention, as viewed from an upstream side in a fluid flow direction.

FIG. 2 is an enlarged developed cross-sectional view of a surface portion taken along line AA of FIG.

FIG. 3 is a front view showing the flow of the present invention when the valve body is at an intermediate opening degree.

FIG. 4 is a plan view showing the flow of the present invention when the valve body is at an intermediate opening degree.

FIG. 5 is a perspective view showing an example of a soft seal gate valve with a part cut away.

FIG. 6 is a sectional view of a surface portion of a conventional valve body.

FIG. 7 is a side view showing a partially closed state of the valve body.

FIG. 8 is a side view showing a partially open state of the valve body in a partially open state.

FIG. 9 is a front view showing a conventional flow when the valve body is at an intermediate opening degree.

FIG. 10 is a plan view showing a conventional flow when the valve body is at an intermediate opening degree.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 valve body 2 valve box 3 valve stem 10 upstream opening of valve box 13 rubber lining layer (elastic material lining layer) 15A to 15D guide groove C1 axis of valve box C2 axis of valve rod O central part of valve element in width direction center

Claims (1)

[Claims] 1. A valve body having a surface covered with an elastic material lining layer is attached to a valve stem having an axis crossing an axis of a valve box, and housed in the valve box so as to be movable forward and backward in the axial direction of the valve stem. In a soft seal gate valve configured to close the valve box by forward movement of the valve body and open the valve box by backward movement of the valve body, the valve body is directed to at least an upstream opening of the valve box in the valve body. A plurality of guides for spreading and dispersing the flow of fluid in the elastic material lining layer of the surface to be spread in a fan shape from the center in the width direction of the valve body on both left and right sides in the width direction and toward the forward direction of the valve body A soft seal gate valve having a groove.