JPH11166628A - Valve device and adjusting method therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To dissolve discrepancy such as difficulties for adjusting pressing force proper with respect to a grand packing and the like can be given. SOLUTION: When a grand packing 6 proceeds in plastic deformation due to secular change while a lower slide packing flange 9 is accordingly lowered down, and when a gap width between both the packing flanges 9 and 10 reaches a prescribed value, which is measured by a gap width measuring instrument, a nut 12 is fastened again against a grand bolt 11 so as to allow a specified fastening force to be given to the grand packing 6. By this constitution, the grand packing 6 is subjected to compression force in one valve shaft direction, and an appropriate stress is incurred in the radial direction so as to allow sealing to be effective, so that fluid is thereby prevented from leaking.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a valve device provided with a mechanism for compensating stress relaxation of a gland packing in a shaft sealing portion, and a method of adjusting the valve device.

[0002]

2. Description of the Related Art FIG. 12 is a longitudinal sectional view of a general valve device provided with a gland packing as a gland seal structure. In the figure, reference numeral 101 denotes a valve shaft having a valve body 102 attached to a lower end thereof, which is moved up and down by an actuator (not shown) connected to the upper end to open and close a flow path formed in the valve box 103. . An upper lid 104 as a shaft support member is attached to the valve box 103,
Inside the upper lid 104, a ground portion 104A through which the valve shaft 101 passes is formed.

[0003] A neck bush 105, a plurality of gland packings 106, a lantern ring 107, a plurality of gland packings 106, and a packing follower 108 are sequentially fitted in the gland portion 104A. 109
Is a packing flange, and the packing follower 10 is tightened by the tightening force of the nut 111 to the ground bolt 110.
Press 8 down. Then, by tightening the nut 111 and pressing the packing follower 108 downward, the sealing surface between the inner peripheral surface of the gland packing 106 and the outer peripheral surface of the valve shaft 101, and the gland packing 106
A surface pressure is generated on the sealing surface between the outer peripheral surface of the inner surface and the inner peripheral surface of the ground portion 104A, and the ground is sealed to prevent the fluid in the flow path from leaking to the outside.

In such a valve, as time passes, the elastic stress of the gland packing 106 decreases, and the surface pressure of the sealing surface decreases. One cause of the decrease in the stress of the gland packing 106 is wear of the inner peripheral surface of the gland packing 106 due to the vertical movement of the valve shaft.

Conventionally, such a gland packing 1
As a method for compensating for the time-dependent decrease in stress of No. 06, for example,
As shown in FIG. 13, there is a method of incorporating a coil spring 112 inside the ground portion 104 </ b> A and pressing the gland packing 106 downward by the coil spring 112. In Japanese Utility Model Laid-Open No. 5-36180, as shown in FIG. 14, a disc spring 113 is incorporated between the packing flange 109 and the nut 111, and the packing flange 109 and the packing follower 10 are mounted by the disc spring 113.
A valve device having a stress compensating mechanism for pressing the gland packing 106 downward through the valve device 8 is described.

[0006]

Since the conventional valve device is constructed as described above, the gland packing 106 is formed by using an elastic member such as a coil spring 112 or a disc spring 113.
Therefore, when the volume of the gland packing 106 decreases to a predetermined amount or more due to a change over time, the elastic force of the elastic member does not act on the gland packing 106, and the gland packing 106 Could not compensate for the significant stress drop.

Therefore, it is necessary to retighten the nut 111 in order to always compensate for the time-dependent decrease in stress of the gland packing 6. At this time, since the fastening of the nut 111 relies on the intuition of the operator, there is a problem that it is difficult to always adjust the nut 111 to give an appropriate pressing force.

That is, the tightening is too weak and the pressure on the sealing surface remains insufficient, or conversely, the tightening is too strong and
For example, it often interfered with the movement of the valve stem. In addition, it is difficult to accurately adjust the tightening of the nut 111 at the time of assembly.

The locations where the elastic members such as the coil spring 112 and the disc spring 113 are provided are shown in FIGS.
As shown in (1), since the number of springs is limited around the valve shaft and the stud bolts, the number and types of springs are also limited. For example, there is a problem that a sufficient pressing force cannot be obtained. For this reason, especially in a valve device used in a portion where a high-pressure fluid flows, the fluid often leaks due to insufficient stress of the gland packing. In addition, a special spring is required, and there is a problem that a mass-produced inexpensive standard product may not be used.

[0010] Further, there is a problem that it is necessary to retighten the wire early as there is no simple and accurate method for judging whether or not the time-dependent decrease in stress of the gland packing 106 exceeds the allowable limit.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-described problems, and always compensates for the time-dependent stress reduction of the gland packing appropriately, sufficiently secures the surface pressure of the sealing surface, It is an object of the present invention to obtain a valve device capable of reliably preventing leakage of a valve.

It is another object of the present invention to provide a method of adjusting a valve device capable of accurately knowing the degree of a time-dependent decrease in stress of a gland packing and maintaining the stress of the gland packing in an optimum state.

[0013]

SUMMARY OF THE INVENTION A valve device according to the present invention includes a packing housing formed around a valve shaft, a gland packing filled between the packing housing and the valve shaft, and a shaft sealing portion. Pressing means pressed against the gland packing from the opening side of the first, a first flange for pressing the packing pressing means, and a second flange disposed to face an outer surface of the first flange. And a fastening member for holding down the gland packing via the first and second flanges and the packing holding means, and an elastic force inserted between the first and second flanges to tighten the fastening member. The gland packing is provided with an elastic member which is generated and constantly applies a compressive force in the direction of the valve shaft to the gland packing via the first flange and the packing pressing means.

In the valve device according to the present invention, the elastic member is provided at a position except at least around the valve shaft and the tightening member.

[0015] The valve device according to the present invention comprises first and second valves.
And a gap width monitoring means for monitoring the width of the gap between the flanges.

In the valve device according to the present invention, the gap width monitoring means includes a scale plate fixed to the first or second flange;
And a pointer fixed to the second or first flange.

The valve device according to the present invention comprises a first or second valve device.
Is provided with a concave portion at a predetermined position, and the first and second flanges are combined to form an accommodating portion for accommodating the elastic means.

[0018] In the valve device according to the present invention, the fastening member is fixed to the shaft seal portion side and penetrates the first and second flanges. It consists of a nut for fastening from the outside.

In the valve device according to the present invention, the first flange and the packing holding means are integrated.

The method for adjusting a valve device according to the present invention is characterized in that, when assembling, the first and second flanges with the elastic member interposed therebetween are in contact with each other, or the first and second flanges are in contact with each other. In a state where the gap width between the opposing surfaces of the second flange is a predetermined value, the gland packing is pressed through the first and second flanges and the packing pressing means using the tightening member, and after assembly, The gap width is monitored by the gap width monitoring means, and when the gap width exceeds a predetermined value, the tightening by the tightening member is performed according to the gap width such that the stress of the gland packing becomes a value within a predetermined range. Either increase the strength or replace the gland packing.

[0021]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below. Embodiment 1 FIG. 1 is a longitudinal sectional view showing a configuration of a valve device according to Embodiment 1 of the present invention, FIG. 2 is a partially enlarged sectional view showing an enlarged part A of FIG. 1, and FIG. 3 is a sectional view taken along line BB of FIG. FIG. 4 is a sectional view taken along the line CC of FIG.

In FIG. 1, reference numeral 1 denotes a valve shaft having a valve body 2 attached to a lower end thereof. The valve shaft 3 is moved up and down by an actuator (not shown) connected to the upper end thereof.
Open and close the flow path formed in the inside. An upper lid 4 as a shaft support member is attached to the valve box 3. Inside the upper lid 4, a gland portion (packing accommodating portion) 4 A through which the valve shaft 1 passes.
Are formed.

In the ground portion 4A, a neck bush 5,
A plurality of gland packings 6, lantern rings 7, a plurality of gland packings 6, and packing followers (packing holding means) 8 are sequentially fitted. 9 is a lower packing flange (first flange), 10 is an upper packing flange (second flange), and both packing flanges 9 and 10 are combined via a disc spring (see FIG. 4) as described later. The disc spring presses the gland packing 6 downward via the lower packing flange 9 and the packing follower 8 by the tightening force of the nut (tightening member) 12 against the ground bolt (tightening member, bolt) 11. Thereby, the inner peripheral surface of the gland packing 6 and the valve shaft 1
Seal surface between the outer peripheral surface of the
A surface pressure is generated on a sealing surface between the outer peripheral surface of the first and the inner peripheral surface of the ground portion 4A, and the ground is sealed so as to prevent the fluid in the flow path from leaking to the outside.

As shown in FIGS. 2 to 4, the lower packing flange 9 and the upper packing flange 10 are respectively
Insertion holes 9a, 10a for inserting the valve shaft 1, insertion holes 9b, 10b for inserting the ground bolt 11, and an insertion hole 9c for inserting the guide bolt 13 for guiding the disc spring (elastic member) 14. , 10c. Also,
A female screw screwed into the guide bolt 13 is screwed into the inner wall of the insertion hole 10c. On the upper surface of the upper lid 4, a female screw portion 4b screwed with the tip of the ground bolt 11 is provided.

At the time of assembly, the valve shaft 1 is inserted into the insertion holes 9a, 10a.
Then, the ground bolt 11 screwed to the female screw portion 4b and fixed to the upper lid 4 is passed through the insertion holes 9b and 10b, and is disposed on the packing follower 8 in the order of the lower packing flange 9 and the upper packing flange 10.

The lower packing flange 9 and the upper packing flange 10 have substantially the same shape. On one surface side, there are provided, for example, two concave portions 9d and 10d each having a cylindrical outer wall, and the concave portions 9d and 10d face each other. The disc spring 14 is accommodated in the spring accommodating portion (accommodating portion) H formed by the concave portions 9d and 10d.

In each spring accommodating portion H, for example, six disc springs 14 are arranged in series while being guided by guide bolts 13, and these disc springs 14 are connected to the lower packing flange 9 and the upper packing flange 10. An elastic force is generated by being sandwiched between and compressed. This elastic force is transmitted by the lower packing flange 9 and the packing follower 8 to apply a compressive force to the gland packing 6.

A scale plate 15a is provided at a predetermined position of the lower packing flange 9, and a pointer 15b is provided at the upper packing flange 10, thereby forming a gap width measuring device 15 (gap width monitoring means). It is used to measure a gap between the upper flange 10 and the lower flange 9.

Next, the operation will be described. First, when the nut 12 is tightened to the ground bolt 11 and, for example, the lower surface of the upper flange 10 and the upper surface of the lower flange 9 are joined, the necessary stress of the gland packing 6 is obtained on the sealing surface. The number (6 in this embodiment) of the disc spring 14 and the spring constant are set in advance. At this time, adjustment is made so that the pointer of the gap width measuring device 15 indicates 0.

After the above preparations, the disc spring 14 is accommodated in the spring accommodating portion H, and the nut 12 is tightened so that the upper surface of the lower packing flange 9 and the upper packing flange 10 are tightened.
And the lower surface of the substrate. At this time, by tightening the nut 12, the disc spring 14 is compressed to generate an elastic force.

The elastic force of the disc spring 14 is transmitted by the lower packing flange 9 and the packing follower 8 and is applied to the gland packing 6. The gland packing 6 receives this compressive force in the valve axis direction, generates a radial stress, seals, and prevents fluid leakage.

When a certain period of time has passed after the assembly and the stress of the gland packing 6 has decreased, the constrained disc spring 14
The packing follower 8 is pushed in by the elastic force of the above, and the stress of the gland packing 6 is compensated. However, here, the lower packing flange 9 is lowered together with the plastic deformation of the gland packing 6, and a gap is generated between the lower packing flange 9 and the upper packing flange 10.

Further, if the gland packing 6 undergoes plastic deformation due to aging, compensation by the elastic force of the disc spring 14 becomes insufficient, so that the width between the two packing flanges 9 and 10 measured by the gap width measuring device 15 is required. When (the lowering amount of the lower packing flange 9) reaches a predetermined value, the nut 12 is tightened against the ground bolt 11 again.

Here, for example, the lower packing flange 9
Until the upper surface of the nut is joined to the lower surface of the upper packing flange 10, that is, until the gap width becomes zero.
Re-tightening. If the retightening strength is insufficient, the tightening force is further adjusted according to the measured gap width. Further, when the gap width becomes very large, the gland packing 6 is replaced.

As described above, according to the first embodiment, in order to compensate for the time-dependent decrease in the stress of the gland packing 6, when retightening the nut 12, it is always appropriate without relying on the worker's intuition. By applying an appropriate pressing force, the effect of adjusting the stress of the gland packing 6 so as to maintain an appropriate value is obtained. Therefore, it is possible to obtain the effect of always appropriately compensating for the time-dependent decrease in stress of the gland packing 6, ensuring sufficient surface pressure on the sealing surface, and reliably preventing fluid leakage.

Further, since the disc spring 14 is provided at a place other than around the valve shaft 1 and the ground bolt 11, an effect that a sufficient pressing force can be given by arranging at many places is obtained. In addition, since an inexpensive standard product that is mass-produced can be used, the effect of reducing costs can be obtained.

Embodiment 2 FIG. 5 is a sectional view showing a configuration of a main part of a valve device according to Embodiment 2 of the present invention, and FIG.
5 is a cross-sectional view along the line D-D. FIG. 7 is a cross-sectional view along the line EE in FIG. The second embodiment of the present invention is significantly different from the first embodiment in that a coil spring is used instead of a disc spring, and the coil spring is sandwiched between two packing flanges from above and below without providing a recess in the packing flange. This is the point configured as follows. Except for this, the configuration is substantially the same as that of the first embodiment, so that the description will be simplified.

5 to 7, 16 is a lower packing flange (first flange), 17 is an upper packing flange (second flange), and 18 is a coil spring (elastic member). As shown in the figure, the lower packing flange 16 and the upper packing flange 17 have insertion holes 16a and 17a for inserting the valve shaft 1 and insertion holes 16b and 17b for inserting the ground bolt 11, respectively. ing.

Guide portions 16c for guiding the coil springs 18 are provided vertically at four predetermined positions of the lower packing flange 16, and the upper portions corresponding to the guide portions 16c when both packing flanges are combined. At a predetermined position of the packing flange 17, an insertion hole 17c for inserting the tip of the guide portion 16c is provided.

At the time of assembly, the valve shaft 1 is inserted into the insertion holes 16a and 17
a, and the ground bolt 11 screwed to the female screw portion 4b and fixed to the upper lid 4 is passed through the insertion holes 16b and 17b, and is disposed on the packing follower 8 in the order of the lower packing flange 16 and the upper packing flange 17.

The lower packing flange 16 and the upper packing flange 17 are aligned and combined so that the respective guide portions 16c to which the coil springs 18 are attached and the insertion holes 17c face each other. Each coil spring 18
An elastic force is generated by being compressed between the lower packing flange 16 and the upper packing flange 17. This elastic force is transmitted by the lower packing flange 16 and the packing follower 8 to apply a compressive force to the gland packing 6.

A scale plate 15a is provided at a predetermined position of the lower packing flange 16, and
Is provided with a pointer 15b, which constitutes a gap width measuring device 15, which is used to measure the gap between the upper flange 17 and the lower flange 16. The operation is substantially the same as the operation of the first embodiment, and the description is omitted.

As described above, according to the second embodiment, the same effects as described in the first embodiment can be obtained. In addition, since the thickness of both packing flanges can be reduced, the effect of reducing costs can be obtained.

Embodiment 3 FIG. FIG. 8 is a cross-sectional view showing a main configuration of a valve device according to Embodiment 3 of the present invention, and FIG.
10 is a sectional view taken along the line FF of FIG. 8, FIG. 10 is a sectional view taken along the line GG of FIG. 8, and FIG. 11 is a perspective view showing an external configuration of the upper flange.

The second embodiment of the present invention is largely different from the first embodiment in that a disc spring is also arranged around the ground bolt, and a recess for accommodating the disc spring is provided only in the upper packing flange. This is the point configured as follows. Except for this, the configuration is substantially the same as that of the first embodiment, so that the description will be simplified.

8 to 11, reference numeral 19 denotes a lower packing flange (first flange), and reference numeral 20 denotes an upper packing flange (second flange). As shown in the figure, the lower packing flange 19 and the upper packing flange 20 are respectively provided with insertion holes 19 through which the valve shaft 1 is inserted.
a, 20a, and insertion holes 19b, 20b through which the ground bolt 11 is inserted.

Further, guide portions 20c for vertically guiding the disc springs 14 are provided at predetermined six locations of the lower packing flange 19 so as to protrude vertically downward, and when the two packing flanges are combined, a lower portion corresponding to the guide portion 20c is provided. Side packing flange 1
9 is provided with an insertion hole 19c through which the distal end of the guide portion 20d is inserted. In addition, a cover portion 20d that extends from the side surface of the disc spring 14 extends vertically below the peripheral edge of the upper packing flange 20.
The disc spring 14 is arranged around the ground bolt 11 in addition to the portion where the guide portion 20c is provided.

At the time of assembly, the valve shaft 1 is inserted into the insertion holes 19a, 20a.
a, and the ground bolt 11 screwed to the female screw portion 4b and fixed to the upper lid 4 is passed through the insertion holes 19b and 20b, and disposed on the packing follower 8 in the order of the lower packing flange 19 and the upper packing flange 20.

The lower packing flange 19 and the upper packing flange 20 are aligned and combined so that the guide rods 20c to which the disc springs 14 are attached and the insertion holes 19c face each other.

Each disc spring 14 is attached to the lower packing flange 1.
The elastic force is generated by being sandwiched and compressed by the upper and lower packing flanges 20 and 20. This elastic force is transmitted by the lower packing flange 19 and the packing follower 8 to apply a compressive force to the gland packing 6.

A scale plate 15a is provided at a predetermined position of the lower packing flange 19,
Is provided with a pointer 15b, which constitutes a gap width measuring device 15, which is used to measure the gap between the upper packing flange 20 and the lower packing flange 19. The operation is substantially the same as the operation of the first embodiment, and the description is omitted.

As described above, according to the third embodiment, the same effects as described in the first embodiment can be obtained. In addition, since the disc spring 14 is arranged also around the ground bolt 11, an effect is obtained that an arbitrary pressing force can be obtained and the adjustment can be performed more easily. Further, since the upper packing flange 20 is configured to cover the lower packing flange 19, for example,
Even when the valve device is installed outdoors, it is possible to prevent the infiltration of rainwater and the like, and it is possible to prevent the rust of the disc spring 14 from being generated and to extend the life of the disc spring 14.

In the above embodiments, the packing follower 8 and the lower packing flange 9 (16, 19) are used.
Has been described as a separate member.
They may be integrated. Further, for example, the amount of reduction in the stress of the gland packing 6 is determined based on the gap width between the two packing flanges measured by the gap width measuring device, and appropriate tightening is performed based on the determined amount of reduction in stress. The amount may be calculated, or a warning may be issued when the stress drop exceeds an allowable range.

[0054]

As described above, according to the present invention, the elastic member applies a compressive force to the gland packing via the first flange and the packing pressing means when the tightening member is tightened. The state of the stress drop can be accurately grasped by the drop of the first flange due to the time-dependent stress drop of the gland packing, and the tightening member necessary for compensating for the time-dependent stress drop of the gland packing. Since the tightening force can be accurately known, there is an effect that an appropriate pressing force is always applied, and the stress of the gland packing can be accurately adjusted so as to maintain a value in an appropriate range. Therefore, it is possible to always appropriately compensate for the time-dependent decrease in stress of the gland packing, sufficiently secure the surface pressure of the sealing surface, and reliably prevent fluid leakage.

According to the present invention, since the elastic member is provided at least at a place other than the vicinity of the valve shaft and the tightening member, for example, it can be arranged at many places to give a sufficient pressing force. effective. In addition, since inexpensive standard products that are mass-produced can be used, there is an effect that costs can be reduced.

According to the present invention, since the gap width monitoring means for monitoring the width of the gap between the first and second flanges is provided, the stress of the gland packing can be more accurately reduced with time. Can be grasped and the required tightening force can be accurately known.
There is an effect that an appropriate pressing force is always applied, and the stress of the gland packing can be accurately adjusted so as to maintain a value in an appropriate range.

According to the present invention, since the gap width monitoring means is composed of the scale plate and the pointer, the gap width monitoring means can be provided at low cost and the state of the reduction in the stress of the gland packing can be easily grasped. is there.

According to the present invention, since the storage portion for storing the elastic member is formed, for example, even when the valve device is installed outdoors, it is possible to prevent rainwater from entering. The effect is obtained that deterioration of the elastic member can be prevented.

According to the present invention, since the fastening member is composed of the bolt and the nut, an effect is obtained that the fastening force can be easily and reliably adjusted.

According to the present invention, since the first flange and the packing pressing means are configured to be integrated, there is an effect that parts can be saved and costs can be reduced.

According to the present invention, since the gap width monitoring means is configured to determine whether or not the degree of stress reduction of the gland packing is within an allowable range, the state of the time-dependent stress reduction of the gland packing is determined. There is an effect that it is possible to obtain a method of adjusting the valve device that can accurately know and maintain the stress of the gland packing in an optimum state.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view showing a configuration of a valve device according to Embodiment 1 of the present invention.

FIG. 2 is a partially enlarged cross-sectional view showing part A of FIG. 1 in an enlarged manner.

FIG. 3 is a sectional view taken along line BB of FIG. 1;

FIG. 4 is a sectional view taken along line CC of FIG. 3;

FIG. 5 is a cross-sectional view showing a main part configuration of a valve device according to Embodiment 2 of the present invention.

FIG. 6 is a sectional view taken along line DD of FIG. 5;

FIG. 7 is a sectional view taken along line EE of FIG. 5;

FIG. 8 is a sectional view showing a configuration of a main part of a valve device according to Embodiment 3 of the present invention.

FIG. 9 is a sectional view taken along line FF of FIG.

FIG. 10 is a sectional view taken along line GG of FIG. 8;

FIG. 11 is a perspective view showing an external configuration of an upper flange.

FIG. 12 is an explanatory diagram for explaining a conventional technique.

FIG. 13 is an explanatory diagram for explaining a conventional technique.

FIG. 14 is an explanatory diagram for explaining a conventional technique.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Valve shaft 4A Gland part (packing accommodation part) 6 Gland packing 8 Packing follower (packing holding means) 9, 16, 19 Lower packing flange (first flange) 10, 17, 20 Upper packing flange (second flange) 9d recess 10d recess 11 Ground bolt (tightening member, bolt) 12 Nut (tightening member) 14 Disc spring (elastic member) 15 Gap width measuring device (gap width monitoring means) 15a Scale plate 15b Pointer 18 Coil spring (elastic) Member) H Spring housing part (housing part)

Claims (8)

[Claims] A sealing container formed around the valve shaft in the shaft sealing portion, a gland packing filled between the packing housing portion and the valve shaft, and a gland packing from an opening side of the shaft sealing portion. Packing holding means having a tip pressed against the gland packing, a first flange for holding the packing holding means, and a second flange disposed to face an outer surface of the first flange; A fastening member for holding down the gland packing via the first and second flanges and the packing holding means;
The elastic member is inserted between the first and second flanges, and an elastic force is generated by the tightening of the tightening member, and the direction of the valve shaft is applied to the gland packing through the first flange and the packing pressing means. And a resilient member for constantly applying a compressive force to the valve device. 2. The valve device according to claim 1, wherein the elastic member is provided at a location other than at least around the valve shaft and the tightening member. 3. The valve device according to claim 1, further comprising a gap width monitoring means for monitoring a width of a gap between the first and second flanges. 4. The gap width monitoring means comprises a scale plate fixed to the first or second flange, and a pointer fixed to the second or first flange. Valve equipment. 5. The first or second flange is provided with a concave portion at a predetermined position, and the first and second flanges are combined to form an accommodating portion for accommodating the elastic means. The valve device according to any one of claims 1 to 4, wherein 6. A bolt fixed to the shaft seal portion side and penetrating through the first and second flanges, and is screwed with the bolt to fasten the second flange from outside. The valve device according to any one of claims 1 to 5, comprising a nut. 7. The valve device according to claim 1, wherein the first flange and the packing holding means are integrated. 8. When assembling, the opposing surfaces of the first and second flanges in which the elastic member is interposed are in contact with each other, or the opposing surfaces of the first and second flanges are in contact with each other. In a state where the gap width between them becomes a predetermined value, the gland packing is pressed through the first and second flanges and the packing pressing means using a fastening member, and after the assembly, the gap width monitoring means The gap width is monitored, and when the gap width exceeds a predetermined value, the tightening strength of the fastening member according to the gap width is adjusted so that the stress of the gland packing becomes a value within a predetermined range. Or increase
Alternatively, a method of adjusting the valve device, wherein the gland packing is replaced.