JP3017659B2 - Gate valve - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gate valve.

[0002]

2. Description of the Related Art As shown in FIG. 5, a gate valve includes a valve box B, a valve cover F covering an upper portion of the valve box B, and a flow path of the valve box B. A valve rod (not shown) for opening and closing, and a valve stem 2 connected to the valve element.
Is rotated in a predetermined direction or the opposite direction about the center axis as a rotation center, whereby the valve body is
Is raised and lowered in a direction substantially orthogonal to the flow path, and the flow path is opened or shut off.

In the conventional gate valve, the packing box 1 is provided above the valve cover F to prevent the fluid in the valve box B from being ejected to the outside of the valve cover F. That is, the packing box 1 includes a cylindrical main body 1a having an insertion hole Y in the center of the inner bottom portion through which the valve stem 2 is inserted, and a collar 1b provided on the outer periphery of the upper part of the main body 1a. A box body is provided, and a plurality of packing members 4 are provided in the body portion 1a so as to surround an outer peripheral portion of the valve stem 2.
4 are arranged.

On the other hand, a packing holding member 5 for holding the packing members 4, 4 is provided above the main body 1a of the packing box 1, and the packing holding member 5 is provided.
Is fitted into the cylindrical main body 1a,
It has a cylindrical holding body 5a having an insertion hole R for inserting the valve stem 2 in the center, and a collar 5b provided on the outer periphery of the upper part of the cylindrical holding body 5a. The flange 5b of the packing holding member 5 and the flange 1b of the packing box 1 have through holes 5c, 5c and screw holes 1c,
1c are provided, and these through holes 5c, 5c
And the screw holes 1c and 1c have male screw portions 7a and 7
b, the bolts 7, 7 with
The nuts 8, 8 are fastened to a, 7a from above.

[0005] Therefore, the packing members 4, 4 in the main body 1 a of the packing box 1 are pressed toward the inner bottom of the main body 1 a by the pressing body 5 a of the packing pressing member 5 and packed around the valve stem 2. . Thus, the packing members 4 and 4 in the main body 1a of the packing box 1 prevent the fluid from being ejected to the outside of the valve lid F through the insertion hole Y.

However, as described above, the gate valve has the packing members 4 and 4 packed around the valve stem 2 to prevent the valve stem 2 from being packed.
When is rotated, the packing materials 4, 4 are worn and damaged. Therefore, when the packing materials 4, 4 have been used for a certain period of time, it is necessary to replace them, but especially when the gate valve is installed at a position lower than the riverbed, for example, the packing material is not used. When the packing materials 4 and 4 are taken out of the main body 1a of the packing box 1,
Due to the fluid pressure, the fluid material spouts through the insertion hole Y of the valve rod 2 and upwards in the main body 1a of the packing box 1, and the packing materials 4, 4 are refilled in such a state. Was difficult.

The present invention has been made in view of such a conventional problem, and an object of the present invention is to remove the fluid inside from the packing box while maintaining the pressurized state. It is an object of the present invention to provide a gate valve that enables replacement of a sealing material such as a packing material.

[0008]

A gate valve according to the present invention has the following configuration to achieve the above object. That is, a packing box is provided to prevent fluid from being ejected through the insertion portion of the valve stem, and the packing box surrounds the outer periphery of the valve stem in a cylindrical packing box body. And a first sealing material such as a packing material placed in the packing, and pressing the first sealing material from above.
A first cylindrical sealing material retainer that is bolted to the kin box body . A second sealing material is placed below the first sealing material so as to surround the outer periphery of the valve stem, and the second sealing material is pressed from above to closely contact the outer peripheral surface of the valve stem. A second cylindrical sealing material retainer is provided on the packing box for the purpose.

Further, the second seal material holding member is provided with a tool hook.
And a hooking portion for the first sealing member, and provided between the outer surface of the first sealing member and the inner surface of the packing box body, and on the inner surface of the packing box body,
A screw portion is formed, and a screw portion to be screwed with the screw portion is formed on an outer surface of a side portion of the second seal material holder. The second seal material holder is screwed together with the screw portion. Is rotated by a tool hung on the hook portion and screwed in, so that when the second seal material holding member is at the pressing position, the second sealing material is pressed and is applied to the outer peripheral surface of the valve rod. The second sealing material retainer is tightly attached to the
By rotating the tool with a hook and loosening the screw, when the second seal material holder is in the non-pressing position,
The pressure is released, and the second sealing material does not adhere to the outer peripheral surface of the valve stem.

[0010] The second seal material retainer is composed of a cylindrical main body and a retainer provided at the center of the lower part of the main body and having an insertion hole through which a valve stem is inserted. desirable. Further, it is preferable that a hook for exclusive tool hooking is provided on the outer periphery of the upper part of the second seal material holder.

[0011]

The second seal member is pressed from above by the second seal member retainer, so that the second seal member comes into close contact with the outer peripheral surface of the valve rod, thereby preventing the fluid from entering the packing box body.

Also, a screw portion on the inner surface of the packing box body,
When the second sealing material retainer is screwed into the packing box main body by screwing the screw portion on the side outer surface of the second sealing material retaining member, the second sealing material retainer advances to the pressing position.
The second sealing material is pressed and comes into close contact with the outer peripheral surface of the valve stem. This prevents the second sealant from intruding fluid into the packing box body.

Conversely, if the screwing of the second sealing material press is loosened, the second sealing material press returns to the non-pressing position, and the pressing of the second sealing material is relaxed, and the second sealing material is pressed. Does not adhere to the outer peripheral surface of the valve stem.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a gate valve according to the present invention will be described below with reference to FIGS.

The gate valve 12 is, for example, a valve rod rising type gate valve, and as shown in FIG. 1, a valve box 14, a valve cover 16 covering the upper part of the valve box 14, and a flow path 18. And a valve element 20 for opening and closing the valve.
The valve body 26 is moved up and down about the center axis of the valve stem 26 by rotating the valve body 26 up and down in a direction substantially orthogonal to the flow path 18 of the valve box 14. The channel 18 is opened or shut off.

A stand S is provided above the valve cover 16. A manual handle H protruding to one side and an electric motor protruding to the opposite side are provided above the stand S. Valve stem rotating part 2 made of M etc.
8 are provided. At the center of the top of the valve lid 16 and the center of the bottom of the stand S, insertion holes S1 and 16a, which are insertion portions, are formed so as to communicate between the inside of the stand S and the inside of the valve lid 16, respectively. , 16a,
A valve stem 26 is inserted into the valve cover 16 from inside the stand S.

Since the valve rod rotating section 28 is connected to the valve rod 26 via a power transmission mechanism, an operator can rotate the handle H or drive the electric motor M. Then, the valve stem rotating part 28 rotates the valve stem 26 to move the valve body 20 up and down.

The gate valve 12 is provided with a packing box B1 for preventing ejection of a fluid, for example, in a lower part inside the stand S. Then, as shown in FIG. 2, the packing box B1 is placed inside the packing box main body 32 so as to surround the outer periphery of the valve stem 26, for example, a first seal made of a plurality of packing materials or the like. Lumber 30
The first seal member 30 is pressed from above.
And a sealing material retainer 44.

More specifically, the packing box main body 32 includes a cylindrical main body 32a formed to stand up from the inner bottom of the stand S, and a brim 32b provided on the upper outer periphery of the main body 32a. , The cylindrical main body 32
In a, for example, a first material such as a packing material made of asbestos or the like is used.
The sealing members 30 are arranged vertically so as to surround the outer periphery of the valve stem 26.

The first seal material retainer 44 has a cylindrical retainer body 44b provided with an insertion hole 44a for inserting the valve stem 26 in the center, and an upper outer periphery of the cylindrical retainer body 44b. And a collar portion 44c provided. Then, the flange portion 44c of the first seal material retainer 44
In the flange 32b of the packing box main body 32, a through hole 44 is provided.
d and a screw hole T are provided, respectively, and these through holes 44d and the screw hole T have male screw portions 46a, 4
6b are passed through, and nuts 48, 46a, 46a, 46b, 46b are passed through the male screw portions 46a, 46a, 46b, 46b.
48, 50, 50 are tightened from above and below. Nut 5
Omitting the tightening of 0, as in the conventional example shown in FIG.
The nut 48 may be tightened only on the upper end side of the bolt 46.

Therefore, the first sealing material 30 such as the packing material is attached to the inside of the packing box main body 32 by the lower end of the holding body 44b of the first sealing material holding unit 44. 36, the first sealing material 30 such as the packing material is provided with a large amount of fluid material that has entered through the insertion holes 16a and S1 to the outside of the valve lid 16. Prevent squirting. However, the first sealing material retainer 44
Is a pressure at which the first sealing material 30 such as a packing material does not completely adhere to the outer peripheral surface of the valve rod 26. In other words, the intruding fluid is slightly applied to the valve rod 26 and the first sealing material. It is preferable that the pressure is adjusted so as to push the first seal member 30 toward the inner bottom of the second seal member retainer 36 with a pressure enough to pass between the first seal member 30 and the second seal member holder 36. This is because the intruding fluid passing between the valve stem 26 and the first seal member 30 reduces the friction between the two and prevents the deterioration of the first seal member 30 as much as possible.

In the packing box B1, a second sealing material 33 placed below the first sealing material 30 such as the packing material so as to surround the valve stem 26, and the second sealing material 33 is provided. In order to press it from above and bring it into close contact with the outer peripheral surface of the valve rod 26, a second seal material holder 36 located between the outer surface of the first seal material 30 such as the packing material and the inner surface of the packing box body 32. Are provided.

Therefore, the first sealing material 3 such as a packing material
At the time of replacement of the first seal material 3 such as the packing material in use,
When the second seal material 33 is pressed from above by the second seal material retainer 36 and is in close contact with the outer peripheral surface of the valve stem 26 even when the second seal material 33 is taken out of the packing box Intrusion into the box body 32 can be prevented. That is, in the case of the illustrated embodiment, the second
Since the seal member 33 is made of, for example, soft synthetic rubber or other synthetic resin, the seal member 33 is elastically deformed by being pressed by the second seal member retainer 36 and closely adheres to the outer peripheral surface of the valve stem 26. This is because the gap P1 provided between the surface and the inner side surface of the second seal material 33 is closed. At this time (when replacing the first sealing material 30 such as a packing material), the valve stem 26 is in a stationary state. There is no need to worry about wear of the second seal material 33.

When the second sealing material holder 36 moves upward from the pressed state in the packing box main body 32 to release the pressing of the second sealing material 33, the second sealing material 33 is shaped. Is returned to its original state, and does not adhere to the outer peripheral surface of the valve stem 26, and the gap P1 is formed again (the state shown in FIG. 2).

More specifically, the second seal material holder 36
Consists of a cylindrical main body 36a and a pressing part 34 provided at the center of the lower part of the main body 36a and having an insertion hole Y1 through which the valve stem 26 is inserted. However, the second sealing material retainer 36 does not necessarily need to have the main body portion 36a and the retainer portion 34 integrally formed as in the above embodiment. For example, as shown in FIG. The part 34 may be formed as a separate body. In this case, it is desirable that the pressing portion 34 be made of, for example, gunmetal. In addition, even if the main body part 36a and the holding part 34 are separate bodies, if the second seal material holder 36 moves up and down by a certain length, the holding part 34 also moves up and down with the movement. However, as shown in FIG. 4, the pressing portion 34 may not necessarily be linked.

On the outer periphery of the flange 36b of the second seal material retainer 36, a plurality of notches D, D and the like for engaging a special tool are provided.
Since a female screw portion 38 is formed on the inner surface of the second member 2 and a male screw portion 40 to be screwed with the female screw portion 38 is formed on an outer surface of a side portion of the main body portion 36a of the second seal material holder 36, While screwing the male screw portion 40 and the female screw portion 38, a special tool (not shown) for tightening and removing is applied to the engagement portion of the notches D, D, and the second seal material holder 36 is screwed. Can be included.

Therefore, when the second seal material holder 36 is located below the packing box main body 32, that is, when it is in the pressed position, the second seal material 33 is pressed and the valve When the second seal material retainer 36 is located on the upper side in the packing box main body 32 by loosening the screwing of the second seal material retainer 36 by closely contacting the outer peripheral surface of the rod 26, that is, the non-press position , The pressure is released, and the second seal member 33 does not adhere to the outer peripheral surface of the valve stem 26.

However, the second sealing material retainer 36
Need not necessarily be configured as in the above embodiment, and may have other shapes and structures as long as the second seal material 33 can be pressed or the pressure can be released. In addition, the relationship between the packing box main body 32 and the second seal material retainer 36 does not necessarily need to be a connection relationship with screws.

The female screw 3 of the packing box body 32
8 is a play portion A1 where no female thread is formed.
An O-ring R1 is provided below the play portion A1 to prevent fluid from entering a threaded portion between the female screw portion 38 and the male screw portion 40.

Next, in this embodiment, a method of mounting the first seal material 30 such as a packing material and the second seal material 33 on the packing box main body 32, and a method of replacing the first seal material 30 such as the packing material. Will be described.

First, a method of mounting the first seal material 30 and the second seal material 33 such as a packing material in the packing box main body 32 will be described. In a state where the bolts 46 and 46 are set up on the brim portion 32b, The nuts 50, 50 are fastened to the male screw portions 46b, 46b from below. Then, the second seal member 33 is placed so as to surround the outer periphery of the valve stem 26. However, after placing the second sealing material 33, the bolts 46, 46
May be set on the collar 32b.

The female thread portion 3 of the packing box body 32
By screwing the male thread portion 40 of the second sealing material retainer 36 to 8, the second sealing material retainer 36 is attached to the inside of the packing box main body 32.

Thereafter, the first sealing material 30 such as the packing material coated with grease for preventing seizure is put on the valve stem 26.
And the inner surface of the main body portion 36a of the second seal material holder 36, and placed so as to surround the valve stem 26. The male threads 46a, 46 of the bolts 46, 46
a is inserted into the insertion hole 44b of the first seal material holder 44, and the nuts 48, 48 are screwed into the male screw portions 46a, 4b.
6a by tightening them from above.
The lower end of the sealing material retainer 44 presses the first sealing material 30 such as a packing material into the packing box main body 32 from above.

After that, a special tool for tightening and removing is applied to the engaging portions of the notches D, D and the like of the second seal material retainer 36 and rotated, so that the second seal material retainer 36 is moved to the packing box body 32. By moving to the upper side, that is, the non-pressing position, the pressing of the pressing portion 34 against the second seal material 33 is loosened. This is because if the second seal material 33 is kept pressed for a long time, it may deteriorate. Therefore, if the first seal material 30 such as a packing material is not replaced, the pressing of the pressing portion 34 is not performed. Loosen the second seal material 33
This is because it is necessary to prevent the deterioration of.

When a fluid flows through the gate valve in a state where the pressing of the holding portion 34 is released, the insertion holes 16a, S
Through 1, the fluid enters the packing box main body 32. This intruding fluid passes through the gap P1 and
As described above, it passes between the valve stem 26 and the first sealing material 30 such as a packing material, and further flows out of the packing box B1 through the insertion hole 44a of the first sealing material retainer 44.
If the pair of left and right nuts 48, 48 is loosely tightened with respect to the male screw portions 46a, 46a, the amount of fluid passing between the valve stem 26 and the first seal material 30 such as a packing material increases, so that The passing amount of the intruding fluid is adjusted by appropriately adjusting the degree of tightening.

When the operator observes the state of the intruding fluid that flows out through the insertion hole 44a, the pair of left and right nuts 48, 4 with respect to the male screw portions 46a, 46a.
8 so that the amount of inflowing fluid flowing out is the same around the valve stem 26,
The degree of tightening of each nut 48, 48 is adjusted.

Next, a method of replacing the first seal material 30 such as a packing material will be described. First, a special tool for tightening and removing is engaged with the notches D, D, etc. of the second seal material retainer 36. Then, the second seal material holder 36 is moved to the lower side of the packing box main body 32, that is, the pressed position. Then, the pressing portion 34 of the second seal material press 36 presses the second seal material 33 against the inner bottom of the packing box B1 to close the gap P1, so that a fluid substance enters the packing box B1. To prevent

Thereafter, the nuts 48, 48 are loosened and removed from the bolts 46, 46 standing on the flange 32b, and the first sealing material retainer 44 is pulled out upward to be removed. The used first sealant 30, 30 is pulled out from the inside of the second sealant retainer 36 in the box main body 32 (see FIG. 3).
The new first sealant 30, 30 is attached to the packing box body 32.
Is inserted into the second sealing material retainer 36 located inside. Then, the first seal member 30 is pressed from above the packing box main body 32 toward the upper surface of the press portion 34 by the lower end portion of the press main body 44a of the first seal material press 44 and fixed by the procedure described above. I do.

The gate valve according to the present invention is not necessarily limited to the above-described embodiment, and various other modifications are possible. For example, as described above, the second seal member 33 is made of a soft material. It is preferably made of synthetic rubber or other synthetic resin, but may be made of other materials, for example, soft natural rubber, and its shape, material, etc. can be arbitrarily changed. Also, the first seal member 30 such as a path Kkin material may be an oil seal, also skin may be made of hemp or the like, a plurality vertically so as to surround the valve stem 26 Although it is preferable to pack the sheets, it is not always necessary to adopt this mode. For example, one step may be used. Conversely, a plurality of second seal members 33 may be packed.

As a mechanism for raising and lowering the valve element 20, other than the valve rod raising type shown in the illustrated embodiment, the valve rod 26 rotates at a fixed position without moving up and down, and only the valve element 20 moves up and down. The valve stem may be of a non-elevating type. Further, a manual handle H or an electric motor M used as a part of the valve shaft rotating portion 28 is used.
It is not necessary to use both of them, and for example, a mechanism that uses one of the two driving forces may be adopted. Further, the mounting position of the packing box B1 does not necessarily need to be provided on the valve lid as in the above-described embodiment, and may be mounted inside the valve lid, for example.

[0041]

As is apparent from the above description, according to the gate valve of the present invention, the second sealing material is provided below the first sealing material such as a packing material. By pressing the sealing material by the second sealing material holding member, the second sealing material is brought into close contact with the outer peripheral surface of the valve stem, and it is possible to prevent the fluid from entering the packing box body. Therefore, even if the first sealing material is taken out of the packing box main body, the fluid substance does not enter the packing box main body, so that the first sealing material such as the packing material is not removed without removing the fluid substance in the flow path of the valve box. Material replacement work becomes possible.

[Brief description of the drawings]

FIG. 1 is a front view, partially in section, of an embodiment of a gate valve according to the present invention.

FIG. 2 is an enlarged sectional view showing a packing box portion of the gate valve.

FIG. 3 is an enlarged sectional view of a packing box portion in a state where a first sealing material such as a packing material is taken out.

FIG. 4 is a view corresponding to FIG. 2, showing another embodiment of the gate valve according to the present invention.

FIG. 5 is an enlarged front view showing a part of a conventional gate valve in cross section.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 12 Gate valve 26 Valve stem 30 First seal material such as packing material B1 Packing box 32 Packing box main body 33 Second
Seal material 36 Second seal material holder 38 Female thread 40 Male thread 44 First
Seal material holder 16a, S1 insertion hole (insertion part)

Claims (2)

(57) [Claims] 1. A gate valve provided with a packing box for preventing a fluid substance from spouting through an insertion portion of a valve stem, wherein the packing box is provided in a cylindrical packing box main body. A first sealing material such as a packing material placed around the outer periphery of the rod and the first sealing material are pressed from above .
As described above, the cylindrical shape is bolted to the packing box body.
And a second sealing material is placed below the first sealing material so as to surround the outer periphery of the valve stem. A cylindrical second seal material retainer is provided on the packing box for pressing from above the upper surface to make close contact with the outer peripheral surface of the valve stem, and the second seal material retainer is used for tooling. Equipped with a hook
Rutotomoni, wherein is provided so as to be positioned between the side outer surface and the inner surface of the packing box body of the first sealing member and the inner surface of the packing box body, together with the screw portion is formed, A screw portion to be screwed with the screw portion is formed on an outer surface of a side portion of the second seal material retainer.
Is screwed by rotating with a tool hung on the hook portion, when the second seal material presser is at the pressing position, the second seal material is pressed and closely adheres to the outer peripheral surface of the valve stem,
In addition, a tool in which a second seal material retainer is hung on the hook portion
When the second sealing member presser is at the non-pressing position, the pressing is released and the second sealing member does not adhere to the outer peripheral surface of the valve stem by loosening the screw by rotating the second sealing member. Gate valve. 2. The second seal material retainer comprises a cylindrical main body and a retainer provided at a lower portion of the main body and having a centrally provided through hole through which a valve stem is inserted. The gate valve according to claim 1, characterized in that: