JP7032247B2 - How to replace the gland packing - Google Patents

Description

The present invention relates to a valve gland packing installation structure.

For the valve, a sealing material called gland packing is used as a shaft sealing material for preventing the fluid from leaking to the outside of the valve while allowing the valve rod to move up and down and rotate (for example, patented). See Document 1).

The gland packing is installed in an installed portion formed in a cylindrical support portion called a stuffing box portion in the valve lid. The gland packing has a role of sealing the gap around the valve stem by being compressed by the holding member and sealing the fluid inside the valve so as not to leak to the outside. Such a gland packing is deformed or damaged after a long period of use, and fluid is likely to leak to the outside. Therefore, the gland packing is replaced with a new one as appropriate or periodically.

Japanese Unexamined Patent Publication No. 2015-129533

Conventionally, asbestos-based gland packing has been the mainstream for gland packing, but with the prohibition of asbestos use, expanded graphite-based gland packing is often used as a substitute. The expanded graphite-based gland packing is excellent in sealing property and the like, but when used under a surface pressure for a long period of time, the graphite component contained in the gland packing may stick to the inner surface of the stuffing box portion. Due to this sticking event, it takes time to remove the old gland packing, and there is a problem that the man-hours for replacing the gland packing increase.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a method for replacing a gland packing that can improve workability at the time of replacing the gland packing.

The present invention for achieving the above object is a method for replacing a gland packing installed on a valve. The valve comprises a valve rod and a valve lid having a cylindrical support through which the valve rod is inserted. The support portion is formed with an installed portion for installing a gland packing that seals between the outer peripheral surface of the valve rod and the inner peripheral surface of the support portion. Then, the inner surface of the installed portion and the sliding surface of the valve stem with the gland packing are coated with a layer that enhances the peelability from the gland packing. The valve lid has a support portion and a lid main body portion to which the support portion is attached and formed separately from the support portion, and the valve rod has a valve body attached to a tip thereof. It has a valve rod and a second valve rod that is detachably connected to the base end of the first valve rod and has a handle attached to an end opposite to the first valve rod. The valve stem is supported by a yoke integrally molded with the valve lid. In the method of replacing the gland packing, with the valve closed, the first valve rod and the second valve rod are disconnected and separated from each other, and the first valve rod and the second valve rod are operated by operating the handle. A space is created between the valve rod and the support portion on which the gland packing is installed, the support portion is moved to the base end side of the first valve rod, and the space is used to take out the support portion from the valve and take it out. After removing the old gland packing from the support portion, a new gland packing is installed on the support portion.

INDUSTRIAL APPLICABILITY According to the present invention, it is possible to provide a gland packing replacement method capable of improving workability at the time of gland packing replacement.

It is a vertical sectional view of the valve to which the gland packing installation structure of the valve which concerns on one Embodiment of this invention is applied. It is an enlarged sectional view of the main part of FIG. It is sectional drawing which follows the line III-III of FIG.

Embodiments of the present invention will be described in detail with reference to the drawings as appropriate.
In each figure, common components and similar components are designated by the same reference numerals, and overlapping description thereof will be omitted as appropriate.

FIG. 1 is a vertical cross-sectional view of a valve 100 to which a valve gland packing installation structure according to an embodiment of the present invention is applied. FIG. 1 shows, as an example of the valve 100, a manual spherical valve used in, for example, a nuclear power plant.

As shown in FIG. 1, the valve 100 includes a valve box 1 in which a flow path 11 through which a fluid flows is formed, and a valve lid 2 that covers an opening 12 formed in the upper part of the valve box 1. The valve lid 2 is fixed to the valve box 1 by bolts 13 and nuts 14.

Further, the valve 100 includes a valve body 3 that opens and closes the flow path 11, a valve rod 4 as a shaft portion to which the valve body 3 is attached to the tip, and a yoke 5 that supports the upper portion of the valve rod 4. .. The valve rod 4 penetrates the valve lid 2 in the vertical direction. The yoke 5 is integrally molded with the valve lid 2 here.

The yoke 5 has a pair of extension portions 51, 51 (only one side is shown in FIG. 1) extending upward in a C shape from two ends located 180 degrees opposite to each other on the upper portion of the valve lid 2. .. The pair of stretched portions 51, 51 are joined at the upper end portion. A mounting hole 52 is formed in the upper end of the yoke 5, which is a joint portion of the pair of stretched portions 51, 51, and the ring member 53 is inserted and fixed in the mounting hole 52. Then, the male screw formed on the valve rod 4 is screwed into the female screw formed on the inner peripheral surface of the ring member 53.

A handle 6 is attached to the upper end of the valve stem 4. By rotating the handle 6, the valve rod 4 moves up and down while rotating, and the valve 100 is opened and closed. For example, the valve body 3 attached to the tip of the valve rod 4 is pressed against the seat portion 15 formed in the flow path 11 in the valve box 1, so that the flow path 11 is closed.

The valve lid 2 has a stuffing box portion 21 as a cylindrical support portion through which the valve rod 4 is inserted. Here, the valve lid 2 has a stuffing box portion 21 and a lid main body portion 20 to which the stuffing box portion 21 is attached and formed separately from the stuffing box portion 21.

A gland packing 7 is mounted between the valve rod 4 and the stuffing box portion 21. The gland packing 7 seals between the outer peripheral surface 41 of the valve rod 4 and the inner peripheral surface 23 of the stuffing box portion 21. A concavely mounted portion 22 is formed on the inner portion of the stuffing box portion 21 facing the outer peripheral surface 41 of the valve rod 4. The inner surface of the installed portion 22 has an inner peripheral surface 23 and a bottom surface 24. A gland packing 7 is installed in the installed portion 22. The gland packing 7 is a known expansion graphite type, and for example, the outer circumference of the expanded graphite tape is coated with a reinforcing material made of knit knit or braid.

The gland packing 7 has a ring shape and includes a plurality of layers 71 stacked in the axial direction of the valve rod 4. FIG. 1 illustrates a case where the gland packing 7 includes six layers 71, but the present invention is not limited to this. The gland packing 7 is pressed from above by the pressing member 31. The pressing member 31 has a cylindrical shape and is externally fitted to the valve rod 4.

A pair of projecting portions 25, 25 (only one side is shown in FIG. 1) project laterally from two ends located 180 degrees opposite to each other in the upper part of the valve lid 2. The protrusion 25 is integrally molded with the valve lid 2 and is located between the pair of extension portions 51, 51 of the yoke 5. The protruding portion 25 has a bifurcated tip portion, and an eyebolt 26 arranged between the protruding portions 25 is swingably supported by a pin 27.

A pressing plate 28 is arranged above the pressing member 31. The pressing plate 28 is externally fitted to the valve rod 4 and is in contact with the upper surface of the pressing member 31. Holes 29 and 29 (only one side is shown in FIG. 1) through which the tip end side of the eyebolt 26 is inserted are formed on both ends of the holding plate 28, respectively. By inserting the tip end side of the eyebolt 26 into the hole 29 and tightening the nut 30, the pressing plate 28 presses the gland packing 7 downward via the pressing member 31 to tighten the holding plate 28. As a result, the gland packing 7 is sandwiched between the pressing member 31 and the bottom surface 24 of the installed portion 22 and compressed in the axial direction, so that the gland packing 7 bulges in the radial direction and becomes the inner peripheral surface 23 of the installed portion 22. It comes into close contact with the outer peripheral surface 41 of the valve rod 4.

The valve rod 4 has a first valve rod 42 to which the valve body 3 is attached to the tip thereof, and a second valve rod 43 detachably connected to the base end of the first valve rod 42. A handle 6 is attached to the end of the second valve rod and 43 opposite to the first valve rod 42.

FIG. 2 is an enlarged cross-sectional view of a main part of FIG. As shown in FIG. 2, the first valve rod 42 and the second valve rod 43 are connected by a valve rod connecting portion 8.

FIG. 3 is a cross-sectional view taken along the line III-III of FIG. As shown in FIG. 3, a pair of concave grooves 44 and 44 are formed on the base end side (second valve rod 43 side) of the first valve rod 42 on opposite sides of each other by 180 degrees. The concave groove 44 has, for example, an arc shape in cross section. Further, on the base end side (second valve rod 43 side) of the first valve rod 42, a pair of flat surfaces 45, 45 are formed 180 degrees opposite to each other. The flat surface 45 is formed so as to recede inward in the radial direction from the outer peripheral surface 41 of the valve rod 4, and is located between the pair of concave grooves 44, 44 in the circumferential direction. On the other hand, a pair of concave grooves 44, 44 and a pair of flat surfaces 45, 45 having the same shape as the first valve rod 42 are also provided on the tip end side (first valve rod 42 side) of the second valve rod 43, respectively. It is formed.

The valve rod connecting portion 8 comprises a pair of plates 46, 46 arranged on both radial sides of the first valve rod 42 and the second valve rod 43, and a pair of plates 46, 46 as the first valve rod 42 and the second valve. A fastening member 47 for fastening with a rod 43 sandwiched between the rods 43 is provided. The fastening member 47 has a bolt 47a and a nut 47b. The plate 46 is formed with a hole (not shown) through which the bolt 47a is inserted. The pair of plates 46, 46 sandwich the first valve rod 42 and the second valve rod 43 in a state of being in contact with the flat surface 45. A part of the shaft of the bolt 47a of the fastening member 47 is arranged so as to enter into the concave groove 44 of the first valve rod 42 and the second valve rod 43. By such a valve rod connecting portion 8, the first valve rod 42 and the second valve rod 43 are firmly connected so as to be able to transmit rotational motion and vertical motion during the rotational operation of the handle 6.

As shown in FIG. 2, the stuffing box portion 21 has a flange 21a that abuts on the outer end surface (upper end surface in FIG. 2) of the lid main body portion 20. The flange 21a is fixed to the outer end surface of the lid main body 20 by a plurality of screw members 32. A seal member 33 is mounted between the flange 21a of the stuffing box portion 21 and the outer end surface of the lid main body portion 20. As the sealing member 33, an O-ring, a gasket, or the like can be used.

The inner peripheral surface 23 and the bottom surface 24, which are the inner surfaces of the installed portion 22 of the stuffing box portion 21, are coated with a layer 34 that enhances the peelability (non-adhesiveness, releasability) from the gland packing 7. Further, here, the sliding surface of the valve rod 4 with the gland packing 7 is also coated with a layer 34 that enhances the peelability from the gland packing 7. The layer 34 that enhances the releasability from the gland packing 7 is made of, for example, a fluororesin or DLC (Diamond-Like Carbon).

Next, the replacement work of the gland packing 7 will be described.
First, with the valve 100 closed, the operator removes the fastening member 47, removes the valve rod connecting portion 8 from the valve rod 4, disconnects the first valve rod 42 and the second valve rod 43, and separates them. Let me. Then, when the operator rotates the handle 6 in the direction of opening the valve 100, only the second valve rod 43 of the valve rod 4 rises, and a space is created between the first valve rod 42 and the second valve rod 43. ..

Subsequently, the operator removes the nut 30 and removes the pressing plate 28 and the pressing member 31 from above the gland packing 7 to expose the upper end surface of the gland packing 7.

Subsequently, the operator removes the screw member 32 and moves the stuffing box portion 21 on which the gland packing 7 is installed to the base end side (upper side in FIG. 1) of the first valve rod 42. As a result, the stuffing box portion 21 is taken out from the lid main body portion 20 and pulled out from the first valve rod 42. Then, the stuffing box portion 21 is taken out from the valve 100 by utilizing the space generated between the first valve rod 42 and the second valve rod 43.

Subsequently, the operator puts the stuffing box portion 21 taken out from the valve 100 at hand and removes the old gland packing 7 from the stuffing box portion 21. This removal work is performed, for example, by using a special tool or the like. Then, a new gland packing 7 is installed in the stuffing box portion 21 from which the old gland packing 7 has been removed. In this way, the gland packing 7 can be replaced.

As described above, the valve gland packing installation structure according to the present embodiment includes a valve rod 4 and a valve lid 2 having a stuffing box portion 21 as a cylindrical support portion through which the valve rod 4 is inserted. Be prepared. The stuffing box portion 21 is formed with an installed portion 22 for installing a gland packing 7 that seals between the outer peripheral surface 41 of the valve rod 4 and the inner peripheral surface 23 of the stuffing box portion 21. Then, the inner surface of the installed portion 22 is coated with a layer 34 that enhances the peelability from the gland packing 7.

According to such a configuration, it is possible to prevent the gland packing 7 from sticking to and sticking to the inner surface of the installed portion 22. That is, when the gland packing 7 is replaced, the gland packing 7 can be easily removed by peeling it from the inner surface of the installed portion 22 with a smaller force.
Therefore, it is possible to provide a valve gland packing installation structure that can improve workability when replacing the gland packing 7.

Further, the gland packing 7 can be easily removed and the working time can be reduced, so that the maintainability of the entire valve 100 can be improved. Further, since the gland packing 7 can be easily removed, there is no event that a part of the old gland packing 7 unintentionally remains in the installed portion 22. As a result, it is possible to completely replace the gland packing 7 with a new one, which is expected to improve the quality and prevent the fluid from leaking to the outside when the valve 100 is used.

Further, in the present embodiment, the sliding surface of the valve rod 4 with the gland packing 7 is coated with a layer 34 that enhances the detachability from the gland packing 7.

According to such a configuration, when the gland packing 7 is replaced, the gland packing 7 can be easily separated from the sliding surface of the valve rod 4 with a smaller force. Therefore, the workability at the time of replacing the gland packing 7 can be further improved.

Further, in the present embodiment, the layer 34 that enhances the releasability from the gland packing 7 is made of a fluororesin such as PTFE (polytetrafluoroethylene) or DLC (Diamond-Like Carbon).

According to such a configuration, it is possible to form a layer 34 that sufficiently enhances the peelability from the gland packing 7 even on a surface that slides in a high temperature environment.

Further, in the present embodiment, the valve lid 2 has a stuffing box portion 21 as a cylindrical support portion and a lid main body portion to which the stuffing box portion 21 is attached and formed separately from the stuffing box portion 21. 20 and.

According to such a configuration, the stuffing box portion 21 can be made into a separate structure independent of the lid main body portion 20. As a result, the coating of the layer 34 that enhances the peelability from the gland packing 7 to the inner surface of the installed portion 22 of the stuffing box portion 21 can be performed by the stuffing box portion 21 alone, and the coating work becomes easy.

Further, the gland packing 7 can be taken out from the valve 100 together with the stuffing box portion 21. Therefore, when replacing the gland packing 7, the stuffing box portion 21 can be handled at hand regardless of the installation status of the valve 100. Therefore, the replacement work of the gland packing 7 becomes easier and the work quality is improved.

Further, in the present embodiment, the valve rod 4 is detachably connected to the first valve rod 42 to which the valve body 3 is attached at the tip and to the base end of the first valve rod 42, which is opposite to the first valve rod 42. It has a second valve rod 43 with a handle 6 attached to the end on the side.

In such a configuration, the valve rod 4 is a detachable two-piece type. Therefore, when the stuffing box portion 21 on which the gland packing 7 is installed is taken out from the valve 100, the first valve rod 42 and the second valve rod 43 can be disconnected and separated. As a result, the stuffing box portion 21 on which the gland packing 7 is installed can be taken out from the valve 100 by utilizing the space formed between the first valve rod 42 and the second valve rod 43. If the valve rod 4 is not a two-piece type, the complicated work of disassembling the valve lid 2 and the valve box 1, removing the handle 6 from the valve rod 4, and then removing the valve rod 4 from the valve lid 2. Is required. After that, the stuffing box portion 21 on which the gland packing 7 is installed must be removed from the lid main body portion 20. That is, by dividing the valve rod into two parts, the complicated work described above can be reduced, and the stuffing box portion 21 on which the gland packing 7 is installed can be easily taken out from the valve 100.

Further, in the present embodiment, the stuffing box portion 21 has a flange 21a that abuts on the outer end surface of the lid main body portion 20, and the flange 21a is fixed to the outer end surface of the lid main body portion 20 by a screw member 32. .. A seal member 33 is mounted between the flange 21a and the outer end surface of the lid main body 20.

According to such a configuration, a surface pressure is applied from the flange 21a to the sealing member 33 by the fastening force of the screw member 32, and the leakage of fluid between the stuffing box portion 21 and the lid main body portion 20 is surely prevented. can do.

Although the present invention has been described above based on the embodiments, the present invention is not limited to the above-described embodiments and includes various modifications. For example, the above-described embodiment has been described in detail in order to explain the present invention in an easy-to-understand manner, and is not necessarily limited to the one including all the described configurations. Further, it is possible to add / delete / replace a part of the configuration of the above-described embodiment with another configuration.

For example, in the above-described embodiment, the case where the gland packing installation structure of the valve according to the present invention is applied to the valve 100 which is a manual spherical valve has been described, but the present invention is not limited thereto. The present invention may also be applied to other types of valves.

2 Operculum 3 Valve body 4 Valve rod 6 Handle 7 Gland packing 20 Lid body 21 Stuffing box (support)
21a Flange 22 Installed part 23 Inner peripheral surface (inner surface)
24 Bottom (inner surface)
33 Seal member 34 Layer 41 Outer peripheral surface 42 1st valve bar 43 2nd valve bar 100 Valve

Claims (3)

It is a method of replacing the gland packing installed on the valve.
The valve is
With a valve bar,
A valve lid having a cylindrical support through which the valve rod is inserted.
The support portion is formed with an installed portion for installing the gland packing that seals between the outer peripheral surface of the valve rod and the inner peripheral surface of the support portion.
The inner surface of the installed portion and the sliding surface of the valve stem with the gland packing are coated with a layer that enhances the peelability from the gland packing.
The valve lid has the support portion and a lid main body portion to which the support portion is attached and formed separately from the support portion.
The valve rod is detachably connected to a first valve rod having a valve body attached to the tip thereof and a base end of the first valve rod, and a handle is attached to an end opposite to the first valve rod. It has a second valve rod and
The second valve rod is supported by a yoke integrally molded with the valve lid.
With the valve closed, the first valve rod and the second valve rod were disconnected and separated.
By operating the handle, a space is created between the first valve rod and the second valve rod.
The support portion on which the gland packing is installed is moved to the base end side of the first valve rod, and the space is used to take out the support portion from the valve.
After removing the old gland packing from the removed support portion, a new gland packing is installed on the support portion.
How to replace the gland packing, which is characterized by this. The method for replacing a gland packing according to claim 1 , wherein the layer for enhancing the peelability from the gland packing is made of a fluororesin or DLC (Diamond-Like Carbon). The support portion has a flange that abuts on the outer end surface of the lid body portion.
The flange is fixed to the outer end surface of the lid main body by a screw member.
The method for replacing a gland packing according to claim 1 , wherein a sealing member is mounted between the flange and the outer end surface of the valve lid.

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