JP3421222B2 - Valve gland seal structure - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a valve gland seal structure in which a plurality of gland packings are stacked on a gland portion of an upper lid through which a valve shaft of a valve passes.

[0002]

2. Description of the Related Art FIG. 7 is a vertical sectional view of a valve having a conventional gland seal structure, and FIG. 8 is an enlarged sectional view of a part of the gland seal structure. In these figures, reference numeral 1 denotes a valve shaft having a valve body 2 attached to a lower end thereof, which is vertically moved by an actuator (not shown) connected to an upper end thereof to open and close a flow passage formed in the valve box 3. To do. An upper lid 4 is attached to the valve box 3, and a gland portion 4A through which the valve shaft 1 passes is formed inside the upper lid 4. A neck bush 5, a plurality of gland packings 6, a lantern ring 7, a plurality of gland packings 6, and a packing follower 8 are sequentially fitted into the gland portion 4A. 9 is a packing flange, and the packing follower 8 is pressed downward by the tightening force of the nut 11 against the gland bolt 10. And nut 11
By tightening and pressing the packing follower 8 downward, the sealing surface between the inner peripheral surface of the gland packing 6 and the outer peripheral surface of the valve shaft 1, and the outer peripheral surface of the gland packing 6 and the inner peripheral surface of the gland portion 4A A ground pressure is generated on the sealing surface between them, and a gland seal is formed so as to prevent the fluid in the flow path from leaking to the outside.

[0003]

Since the conventional gland seal structure is constructed as described above, the direction in which the gland packing 6 is pressed by the packing follower 8 (the axial direction of the valve shaft 1) and the surface pressure on the sealing surface are Since the direction (the direction orthogonal to the axis of the valve shaft 1) is different, the tightening force of the nut 11 is not efficiently converted as the surface pressure generating force,
There was a problem that sufficient surface pressure could not be secured even if the nut 11 was strongly tightened. In particular, in the seal surface between the inner peripheral surface of the gland packing 6 and the outer peripheral surface of the valve shaft 1, the inner peripheral surface of the gland packing 6 is worn by the vertical movement of the valve shaft 1, so that the arrow in FIG. Like Y, fluid leakage along the valve shaft 1 was likely to occur.

The present invention has been made to solve such a problem, and obtains a gland seal structure for a valve which can sufficiently secure the surface pressure of the seal surface and reliably prevent fluid leakage. The purpose is to

[0005]

According to another aspect of the invention, there is provided a gland seal structure for a valve, wherein a slit extending substantially along the axial direction of the valve shaft is formed in a peripheral wall of a gland portion of an upper lid. Upper lid to reduce the width of the slit
Is provided with a tightening member for tightening the peripheral wall of the gland portion in the diameter reducing direction.

In the valve gland seal structure according to the second aspect of the present invention, the slit is opened at the end portion of the upper lid.

In the gland seal structure for a valve according to the third aspect of the present invention, the length of the slit in the axial direction of the valve shaft is from the half of the thickness of one gland packing to the thickness of two gland packings. It was done.

In the gland seal structure for a valve according to the fourth aspect of the present invention, when the peripheral wall of the gland portion is tightened by the tightening member by a predetermined amount in the diameter reducing direction, the inner surfaces of the slits are in close contact with each other.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of the present invention will be described below. Embodiment 1. 1 to 4 are views for explaining the first embodiment of the present invention, in which the same parts as those in the conventional example described above are designated by the same reference numerals and the description thereof will be omitted.

In this example, a slit 4B having a predetermined length L extending in the longitudinal direction of the valve shaft 1 is formed on the peripheral wall of the gland portion 4A of the upper lid 4. This slit 4B
2 are formed so as to divide the peripheral wall of the ground portion 4A into two parts on the left and right in FIG. 2, and the upper ends thereof are open to the upper end of the upper lid 4. The length L of the slit 4B is from half the thickness of one sheet of the gland packing 6 to the thickness of two sheets of the gland packing 6, and the slit 4B
Has a width W of 1 mm or less. In addition, the upper lid 4 has
Two sets of bolts 12 and nuts 13 are attached as tightening members for tightening the peripheral wall of the ground portion 4A in the diameter reducing direction. The bolt 12 is attached so as to cross the slit 4B, and in the case of this example, the base end of the bolt 12 is embedded and fixed in the left side portion of the upper lid 4 in FIG. 2 is projected outward from a through hole 4C formed in the right side portion of the upper lid 4 in FIG. A nut 13 is screwed onto the tip of the bolt 12.

Next, the operation will be described. Similarly to the above-described conventional example, by tightening the nut 11, the gland packing 6 is pressed in the vertical direction in the vertical direction, and the sealing surface between the inner peripheral surface of the gland packing 6 and the outer peripheral surface of the valve shaft 1 and Outer peripheral surface of gland packing 6 and gland portion 4
Surface pressure is generated on the sealing surface between the inner peripheral surface of A and the inner peripheral surface. Further, in the case of this example, by tightening the nut 13, the direction in which the peripheral walls of the ground portion 4A, which are divided into two parts in the left and right in FIG. 2 by the slit 4B, approach each other, that is, the width W of the slit 4B is reduced. The peripheral wall of the gland portion 4A is tightened in the direction of reducing the diameter. Thus, FIG.
By tightening the peripheral wall of the gland portion 4A from the lateral directions in the middle, left and right, the surface pressure of the sealing surface between the gland packing 6 and the valve shaft 1 and the sealing surface between the gland packing 6 and the gland portion 4A are increased. It will be.

As described above, as a result of the vertical tightening by the nut 11 and the horizontal tightening by the nut 13,
It is possible to secure sufficient surface pressure on the sealing surface and reliably prevent fluid leakage. Further, it is possible to prevent the fluid leakage in the direction of the arrow Y in FIG. 1, that is, the leakage of the fluid along the outer peripheral surface of the valve shaft 1, which is likely to occur because the inner peripheral surface of the gland packing 6 is worn by the vertical movement of the valve shaft 1. . Since there is no sliding contact on the seal surface between the outer peripheral surface of the gland packing 6 and the inner peripheral surface of the gland portion 4A, fluid leakage in the direction of arrow X in FIG. FIG. 4 shows the surface pressure of the seal portion in each part in such a gland portion 4A, where the horizontal axis is the surface pressure and the vertical axis is the position in the gland portion 4A in the vertical direction of FIG. As shown in this Figure 4,
Especially, in the upper portion of the gland portion 4A, the nut 13
A suitable surface pressure was secured by tightening in the lateral direction.

In the first embodiment, the length L of the slit 4B is set to be half the thickness of one gland packing 6 to the thickness of two gland packings 6. As a result, the tightening force applied to the peripheral wall of the gland portion 4A can be reliably applied to the gland packing 6, and a suitable surface pressure as shown in FIG. 4 can be secured.
Further, by setting the width W of the slit 4B to be 1 mm or less, when the nut 13 exerts an excessive tightening force, the inner surface of the slit 4B comes into close contact with the nut 4 to prevent excessive tightening. The width W of the slit 4B is 1
The degree of tightening may be increased by setting it to be mm or more. Further, since the slit 4B is opened at the upper end of the upper lid 4, the slit 4B can be easily formed by notching it upward.

It should be noted that at least one slit 4B may be formed, and the point is that the diameter reduction of the peripheral wall of the ground portion 4A is acceptable. Further, the slit 4B is at least the valve shaft 1
It suffices that the gland packing 6 extends substantially along the longitudinal direction thereof, and may have a shape that does not expose the gland packing 6 to the outside. As a tightening member that tightens the peripheral wall of the ground portion 4A in the diameter reducing direction, the slit 4B is crossed as shown in FIG.
By using a bolt passing through the through hole 4C from the right side to the left side in the inside and screwing the left end side of the bolt to the portion of the upper lid 4 on the left side in FIG. 2, the left and right ground parts 4 in FIG.
The peripheral walls of A may be close to each other. Also,
The shape of the ground portion 4A, the shape of the packing follower 8 and the like are not specified and are arbitrary.

Embodiment 2. FIG. 5 is a side view of a main part for explaining the second embodiment of the present invention. In the case of the present example, the slit 4B is not opened to the upper end of the upper lid 4 but extends in the vertical direction. It is formed as a hole. Other configurations are the same as those in the first embodiment described above.

Also according to the second embodiment, the ground portion 4
By tightening the peripheral wall of A in the direction to reduce the diameter,
The surface pressure of the sealing surface can be sufficiently increased to prevent fluid leakage.

Embodiment 3. FIG. 6 is a cross-sectional view of the upper lid 4 for explaining the third embodiment of the present invention. In the case of this example, the band 14 is attached to the outer peripheral surface of the peripheral wall of the ground portion 4A.
And the ends of the band 14 are connected by bolts 15 and nuts 16. Therefore, the band 14 can tighten the peripheral wall of the ground portion 4A to reduce the diameter of the peripheral wall.

Also according to the second embodiment, the ground portion 4
By tightening the peripheral wall of A in the direction to reduce the diameter,
The surface pressure of the sealing surface can be sufficiently increased to prevent fluid leakage.

[0019]

As is evident from the foregoing description, according to the first aspect of the invention, the peripheral wall of the ground portion of the upper lid, a slit extending substantially along the axial direction of the valve shaft, further, the Sri
Since it has a tightening member that tightens the peripheral wall of the gland part of the upper lid in the diameter reducing direction so as to reduce the width of the cover ,
By tightening the peripheral wall of the gland portion of the upper lid in the diameter reducing direction, there is an effect that the surface pressure of the sealing surface between the gland packing and the valve shaft can be sufficiently secured, and fluid leakage can be reliably prevented. .

According to the second aspect of the invention, since the slit is opened at the end portion of the upper lid, there is an effect that the slit can be easily formed by cutting it out.

According to the third aspect of the invention, the length of the slit in the axial direction of the valve shaft is set to 1 of the gland packing.
By making the length from half of the thickness of the sheet to the thickness of two sheets, the tightening force in the diameter reducing direction applied to the peripheral wall of the gland part is surely applied to the gland packing, and the surface pressure of the sealing surface is further increased. There is an effect that it can be sufficiently secured.

According to the fourth aspect of the present invention, when the peripheral wall of the gland portion is tightened in the diameter reducing direction by the tightening member, the inner surfaces of the slits are in close contact with each other, so that the peripheral wall of the gland portion is excessively large. There is an effect that it is possible to prevent tightening.

[Brief description of drawings]

FIG. 1 is a sectional view of a gland seal structure portion according to a first embodiment of the present invention.

FIG. 2 is a view on arrow II in FIG.

FIG. 3 is a view on arrow III in FIG.

FIG. 4 is an explanatory diagram of a surface pressure of a seal surface in the gland seal structure of FIG.

FIG. 5 is a side view of a gland seal structure portion according to a second embodiment of the present invention.

FIG. 6 is a transverse sectional view of a gland seal structure portion according to a third embodiment of the present invention.

FIG. 7 is a vertical sectional view of a valve having a conventional gland seal structure.

8 is an enlarged cross-sectional view of a gland seal structure portion in FIG.

[Explanation of symbols]

1 valve shaft 2 valve body 3 valve box 4 Upper lid 4A ground section 4B slit 4C through hole 5 neck bush 6 gland packing 7 Lantern ring 8 Packing followers 9 packing flange 10 ground bolt 11 nuts 12 bolts (tightening members) 13 Nut (tightening member)

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Claims (4)

(57) [Claims] 1. A gland seal structure for a valve, comprising a plurality of gland packings stacked on a gland portion of an upper lid through which a valve shaft of the valve passes, wherein a gland portion of the upper lid has a peripheral wall in the axial direction of the valve shaft. A gland seal structure for a valve, comprising a slit extending substantially along a slit, and a tightening member for tightening a peripheral wall of the gland portion of the upper lid in a diameter reducing direction so as to reduce a width of the slit . 2. The gland seal structure for a valve according to claim 1, wherein the slit is open to an end portion of the upper lid. 3. The length of the slit in the axial direction of the valve shaft is half the thickness of one sheet of the gland packing to the thickness of two sheets. Alternatively, the gland seal structure of the valve according to claim 2. 4. The inner surface of the slit is in close contact with each other when the peripheral wall of the gland portion is tightened by the tightening member in a diameter reducing direction by a predetermined amount. A gland seal structure for a valve according to any one of the items.