JP2010255661A - Packing material and gland packing using the material - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide gland packing and a packing material used for the gland packing harmonizing heat resistance, durability, a sealing property, lubricity (low torque property) and compression stability on a high level and suitably used under high-pressure and high-temperature conditions of a thermal power plant, a nuclear power plant or the like. <P>SOLUTION: The packing material is formed by twisting a first expanded graphite tape of a strip shape to cover a core material to form a first filament, knitting a reinforcing wire material to cover the periphery of the first filament to form a second filament, and winding a second expanded graphite tape of a strip shape to cover the periphery of the second filament. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a packing material and a gland packing using this material, and more particularly to a packing material capable of achieving both low torque and high sealing performance and a gland packing using this material.

Conventionally, gland packing is used to seal shafts of fluid equipment such as pumps and valves. However, in thermal power plants and nuclear power plants, high pressure and high temperature conditions (for example, ultra super critical pressure (374 ° C or higher)) Since a large number of gland packings are pressurized and accommodated in the stuffing box, the rotational torque of the shaft (valve stem) becomes high and a large load is likely to be applied to the torque motor.
Therefore, the gland packing used in such a situation is required to have a high level of heat resistance, durability, sealability, lubricity (low torque), and compression recovery.

  However, conventional expanded graphite gland packing cannot harmonize heat resistance, durability, sealability, lubricity (low torque), and compression recovery at a high level, so thermal power plants, nuclear power plants, etc. It was difficult to use for a long period of time under high pressure and high temperature conditions.

In view of the above situation, the applicant of the present application has proposed a gland packing having a structure in which an expanded graphite tape and a flat strip-like carbon fiber bundle are combined in Patent Document 1 below.
This gland packing is excellent in that it can exhibit sufficient durability and high lubricity under high temperature and high pressure conditions, but it has further improved properties, especially lubricity (low torque) and sealability. Further improvements were desired.

Japanese Patent Laid-Open No. 2004-232806

  The present invention is a further improvement over the gland packing disclosed in Patent Document 1, and harmonizes heat resistance, durability, sealability, lubricity (low torque), and compression recovery at a high level. The present invention provides a gland packing suitable for use under high-pressure and high-temperature conditions such as a thermal power plant and a nuclear power plant, and a packing material used therefor.

  According to the first aspect of the present invention, the first expanded graphite tape in a band shape is twisted so as to cover the core material to form a first thread, and the reinforcing wire is knitted so as to cover the periphery of the first thread. The present invention relates to a packing material characterized in that a second filamentous body is formed and a band-shaped second expanded graphite tape is wound so as to cover the periphery of the second filamentous body.

  The invention according to claim 2 is a first thread-like body in which a laminated tape obtained by laminating a strip-shaped first expanded graphite tape and one or more first reinforcing fibers is twisted so as to cover the core material, A reinforcing wire is knitted so as to cover the periphery of the first filamentous body to form a second filamentous body, and a band-shaped second expanded graphite tape is wound so as to cover the periphery of the second filamentous body. It relates to packing material.

  The invention according to claim 3 is characterized in that the core material is coated with a swellable clay material, and the swellable clay material is subjected to heat treatment in which interlayer cations are replaced with lithium ions. The packing material according to claim 1 or 2.

  The invention according to claim 4 relates to the packing material according to any one of claims 1 to 3, wherein the swellable clay material is impregnated or coated on the first reinforcing fibers.

  The invention according to claim 5 relates to the packing material according to any one of claims 1 to 4, wherein the swellable clay material is impregnated or coated on the first expanded graphite tape.

  The invention according to claim 6 relates to the packing material according to any one of claims 1 to 5, wherein the swellable clay material is impregnated or coated on the second filamentous body.

  The invention according to claim 7 relates to the packing material according to any one of claims 1 to 6, wherein the swellable clay material is impregnated or coated on the second expanded graphite tape.

  The invention according to claim 8 relates to the packing material according to any one of claims 1 to 7, wherein the second expanded graphite tape contains second reinforcing fibers.

  The invention according to claim 9 relates to the packing material according to any one of claims 1 to 8, wherein the core material is made of stainless steel or Inconel.

  The invention according to claim 9 relates to the packing material according to any one of claims 1 to 9, wherein the reinforcing wire is made of stainless steel or Inconel.

  The invention according to claim 11 relates to the packing material according to any one of claims 8 to 10, wherein the second reinforcing fiber is made of carbon fiber.

  A twelfth aspect of the present invention relates to a gland packing formed by braiding the packing material according to any one of the first to eleventh aspects and press-molding the braided body into a predetermined shape.

  According to the first aspect of the present invention, the strip-shaped first expanded graphite tape is twisted so as to cover the core material to form the first thread-like body, and the reinforcing wire material is covered so as to cover the periphery of the first thread-like body. Is a packing material formed by winding a band-shaped second expanded graphite tape so as to cover the periphery of the second filamentous body, so that the second filamentous body is formed by the knitted reinforcing wire. While being reinforced, the first expanded graphite tape and the second expanded graphite tape bite into the knitting of the reinforcing wire, so that the reinforcing wire, the first expanded graphite tape, and the second expanded graphite tape are firmly integrated. Thereby, the durability of the packing material is improved, and excellent durability can be exhibited even under high temperature and high pressure conditions. Further, since the belt-shaped second expanded graphite tape is wound so as to cover the periphery of the second filamentous body, the sealing property is also excellent.

  According to the second aspect of the present invention, the first filamentous body is formed by twisting a laminated tape obtained by laminating a strip-shaped first expanded graphite tape and one or more first reinforcing fibers so as to cover the core material. Therefore, the first filamentous body is reinforced by the first reinforcing fibers, and a packing material excellent in strength and durability is obtained.

  According to the inventions according to claims 3 to 7, the swellable clay material is present in at least one of the core material, the first reinforcing fiber, the first expanded graphite tape, the second filament, and the second expanded graphite tape. Since it is impregnated or coated, excellent lubricating properties (low torque properties) can be exhibited under high temperature and high pressure conditions by retaining lubricating oil between layers of the swellable clay material. In addition, the swellable clay material is prevented from being dispersed by water because the interlayer cations are replaced with lithium ions and subjected to heat treatment, and has excellent water resistance. Furthermore, the high heat resistance of the swellable clay material can improve the heat resistance of the packing material.

  According to the invention of claim 8, since the second expanded graphite tape contains the second reinforcing fiber, the strength of the second expanded graphite tape is enhanced by the second reinforcing fiber, and the durability of the packing material is improved. Can be made.

  According to the ninth and tenth aspects of the present invention, since the core material or the reinforcing wire is made of stainless steel or Inconel having high strength and excellent corrosion resistance, the durability of the packing material can be improved.

  According to the invention concerning Claim 11, since the 2nd reinforcement fiber included in the 2nd expansion graphite tape consists of carbon fibers, the 2nd expansion graphite tape is reinforced and it can improve the endurance of packing material. it can. Moreover, since the second reinforcing fiber is not exposed, the stem or the like can be prevented from being damaged.

  According to the twelfth aspect of the invention, since the gland packing is formed by braiding the packing material according to any one of the first to eleventh aspects and press-molding the braided body into a predetermined shape, Heat resistance, durability, sealability, lubricity (low torque), and compression recovery can be harmonized at a high level, and used under high pressure and high temperature conditions such as thermal power plants and nuclear power plants. Suitable gland packing.

It is a perspective view which expands and shows the cross section of the packing material which concerns on this invention. It is a figure which shows the manufacturing method of the packing material which concerns on this invention. (A) is a perspective view which shows a 1st filamentous body, (b) is a figure which shows a mode that a 1st filamentous body is formed. It is a figure which shows an example of the string obtained by braiding the packing material which concerns on this invention. It is a perspective view which shows an example of the gland packing which concerns on this invention.

Hereinafter, preferred embodiments of a packing material according to the present invention and a gland packing using the material will be described with reference to the drawings.
FIG. 1 is an enlarged perspective view showing a cross section of the packing material according to the present invention, and FIG. 2 is a view showing a method for manufacturing the packing material according to the present invention.

The packing material (1) according to the present invention comprises a laminated tape (4) in which a strip-shaped first expanded graphite tape (2) and one or more first reinforcing fibers (3) are laminated, 5) is twisted to cover the first thread (6), and the reinforcing wire (7) is knitted to cover the periphery of the first thread (6) to form the second thread (8). The belt-shaped second expanded graphite tape (9) is wound so as to cover the periphery of the second filament (8).
The diameter of the packing material (1) is set in a range of φ1.2 to 3.0 mm, for example.

Fig.3 (a) is a perspective view which shows a 1st filamentous body (6), FIG.3 (b) is a figure which shows a mode that a 1st filamentous body (6) is formed.
The first filament (6) is composed of a laminated tape (4) obtained by laminating a strip-shaped first expanded graphite tape (2) and one or more first reinforcing fibers (3). It is formed by twisting so as to cover.

The first expanded graphite tape (2) and the first reinforcing fiber (3) may be laminated and integrated via the adhesive layer (14), or may be simply overlapped without using an adhesive.
The kind of the adhesive constituting the adhesive layer (14) is not particularly limited, and may be selected from various adhesives such as an organic adhesive, an inorganic adhesive, and an inorganic / organic mixed adhesive. For example, polyvinyl alcohol (PVA) is preferably used. Moreover, heat-fusion films, such as a PVA nonwoven fabric, a PVA film, a polyethylene film, an olefin film, and a urethane film, can also be used.

  As the first expanded graphite tape (2), graphite powder such as natural graphite, pyrolytic graphite, quiche graphite, etc. is reacted with concentrated sulfuric acid, concentrated nitric acid, etc. to form an intercalation compound, and then the residual compound is washed with water. It is possible to use a flexible expanded graphite itself obtained by rapid heating and expansion, compression-molded with a roll material or the like into a sheet shape, and cut into a strip shape.

The density of the first expanded graphite tape (2) is not particularly limited, but is preferably 0.80 to 2.2 g / cm ³ . When the density is in this range, crystal-level irregularities are formed on the surface of the expanded graphite tape, and an anchor effect can be generated between the first reinforcing fibers (3) laminated thereon. On the other hand, if the density is less than 0.80 g / cm ³ , the texture of the structure becomes too rough, and the sealing performance when packing is likely to be deteriorated. On the other hand, if the density exceeds 2.2 g / cm ³ , the texture becomes too fine to make it difficult to produce an anchor effect, and it may not be possible to satisfactorily laminate the first reinforcing fiber (3). .

  The thickness of the first expanded graphite tape (2) is not particularly limited, but is preferably about 0.1 to 1.5 mm, more preferably about 0.2 to 0.4 mm. If the thickness is less than 0.1 mm, the excellent heat resistance, corrosion resistance, and wear resistance of the expanded graphite cannot be expressed well. Further, such an extremely thin material is difficult to manufacture and is not economical. Conversely, if the thickness exceeds 1.5 mm, the expanded graphite tends to be brittle.

  The width of the first expanded graphite tape (2) is preferably 3 to 10 mm, and more preferably 4 to 5 mm. If the width exceeds 10 mm, the flexibility may be reduced, making it difficult to process. On the other hand, if the width is less than 3 mm, the allowable tensile force is extremely reduced, and there is a possibility of breaking during processing.

As the first reinforcing fiber (3), an acrylic or pitch carbon fiber, an inorganic fiber made of glass, ceramic, rock wool, or the like is preferably used.
When using a plurality of carbon fibers, an opened band-like carbon fiber bundle (hereinafter referred to as an opened fiber bundle) is preferably used. FIG. 3B illustrates a case where a spread fiber bundle is used as the first reinforcing fiber (3).
The spread fiber bundle reinforces the first expanded graphite tape (2), supplements the elasticity that tends to be insufficient for the expanded graphite tape, and can also serve as a solid lubricant.
The spread fiber bundle is a belt-like fiber assembly in which the carbon fiber bundle is flattened from the original width to the required width. This spread fiber bundle is excellent in mechanical strength, and various properties such as mechanical strength hardly change between −200 ° C. and + 600 ° C., and both low temperature characteristics and high temperature characteristics are excellent. . Accordingly, the spread fiber bundle can surely reinforce the first expanded graphite tape (2) not only in a normal temperature range but also in a severe temperature environment.
In addition, since the spread fiber bundle is excellent in corrosion resistance and wear resistance, it can withstand long-term use even in harsh environments such as thermal power plants and nuclear power plants.

  The thickness of the spread fiber bundle is preferably 0.01 to 0.5 mm, more preferably 0.15 to 0.4 mm. This is because if the thickness is less than 0.01 mm, sufficient lubricity and sealing properties cannot be obtained, and conversely if the thickness exceeds 0.5 mm, sufficient flexibility cannot be obtained.

  The method for producing the spread fiber bundle is not particularly limited. For example, a fiber bundle (carbon fiber bundle) called a multifilament can be thinly and widened by using ultrasonic waves or fluid flow. The band width at this time is set to be the same as that of the first expanded graphite tape (2), preferably 3 to 10 mm, and more preferably 4 to 5 mm.

  The first filament (6) is formed by twisting the laminated tape (4) obtained by laminating the first expanded graphite tape (2) and the first reinforcing fiber (3) so as to cover the core material (5). (See FIG. 3). At this time, it is preferable that the first reinforcing fiber (3) is on the inner side (on the side of the core material (5)) because the fiber is surely prevented from being exposed to the outer surface when the packing is formed.

Although not shown, in the present invention, a configuration using only the first expanded graphite tape (2) instead of the laminated tape (4), that is, a configuration not using the first reinforcing fiber (3) may be employed.
In this case, the first filamentary body (6) is formed by twisting the strip-shaped first expanded graphite tape (2) so as to cover the core material (5).

In the present invention, at least one (preferably all) of the expanded graphite tape (2), the first reinforcing fiber (3), and the core material (5) is impregnated with a lithiated swellable clay material. It is preferably coated. The thickness of the coating is set to 0.01 to 0.02 mm, for example. Further, the coating may be formed on one side or on both sides.
In FIG. 1, the swellable clay material in which the hatched portion (11) is lithiated is shown.

The swellable clay material, an octahedral layer comprising a octahedral crystal structure, the unit layer of the sandwiched by a pair of tetrahedral layers composed of tetrahedral crystal structure are stacked several layers, each unit layers Na ⁺ , K ⁺ , Ca ²⁺ , Mg ^{2+ and the} like having an interlayer cation (exchangeable cation) are used.
Specifically, smectites such as montmorillonite, beidellite, saponite, hectorite, stevensite, and soconite are used.
Of these, montmorillonite or stevensite is particularly preferably used in the present invention. The reason is that these smectites have vacant sites in the octahedral layer, and lithium ions described later can exist stably. Bentonite mainly composed of montmorillonite can also be used.

  In the swellable clay material used in the present invention, all or part (preferably at least 50% or more) of the above-mentioned interlayer cations are replaced with lithium ions, and heat treatment is performed (that is, Lithiated).

  Examples of the method of replacing the interlayer cation with lithium ions include a method of dispersing the swellable clay material in water together with lithium ions. When a lithium compound is added to an aqueous dispersion of a swellable clay material, interlayer cations and lithium ions between unit layers are ion-exchanged, whereby all or part of the interlayer cations are replaced with lithium ions.

  As the lithium compound, one or more lithium compounds such as lithium hydroxide, lithium chloride, and lithium sulfate are used. Of these, lithium hydroxide that does not contain an anion serving as an impurity is most preferably used. The lithium compound is preferably added in an amount of 1 to 30 times the amount of interlayer cations (ion exchange capacity) in order to sufficiently perform ion exchange.

Next, the clay material in which the above-mentioned interlayer cations are replaced with lithium ions is heat-treated.
The temperature condition for the heat treatment is preferably 230 ° C. or higher, more preferably 300 ° C. or higher, and most preferably 350 ° C. or higher. Exceeding 800 ° C. is not preferable because clay deteriorates. The treatment time is preferably 20 minutes or more and 24 hours or less, and may be a long time when the temperature is low.
By performing the heat treatment, at least a part of the lithium ions between the unit layers can be moved into the octahedral layer. When lithium ions move into the octahedral layer, interlayer cations between the unit layers are reduced and the hydration power is lowered, so that water resistance is improved (water dispersibility is lost).

The core material (5) is immersed in the clay material (12) in which all or part of the interlayer cations are replaced with lithium ions by adding a lithium compound to the aqueous dispersion of the swellable clay material (see FIG. 2). After that, heat treatment is performed.
The expanded graphite tape (2) and the first reinforcing fiber (3) may be subjected to heat treatment after being immersed (not shown) in the clay material (12), or a clay film may be formed from the clay material (12). It may be prepared and heat-treated, and the heat-treated clay film may be laminated on one side or both sides of the expanded graphite tape (2) or the first reinforcing fiber (3).
Moreover, about heat processing, you may carry out in the stage after forming the 1st filamentous body (6), you may carry out in the stage after forming the 2nd filamentous body (8), and packing material ( You may carry out in the step after forming 1).

The swellable clay material may be composed of a modified clay that has been subjected to organic cation treatment or silylation treatment.
As the organic cation, a quaternary ammonium cation or a quaternary phosphonium cation is used. Although it does not specifically limit as a quaternary ammonium cation, A dimethyl dioctadecyl type, a dimethyl stearyl benzyl type, and a trimethyl stearyl type are illustrated.
The silylating agent is not particularly limited, and examples thereof include methyltrimethoxysilane, methyltriethoxysilane, propyltrimethoxysilane, butyltrimethoxysilane, hexyltrimethoxysilane, and octyltrimethoxysilane.

A reinforcing wire (7) is knitted so as to cover the periphery of the first thread (6) described above to form a second thread (8) (see FIG. 2).
Examples of the material of the reinforcing wire (7) include stainless steel (SUS304, SUS316, SUS316L, etc.), inconel, nickel, nickel alloy, and stainless steel or inconel is preferably used from the viewpoint of strength and corrosion resistance. Most preferably, Inconel is used.
The diameter of the reinforcing wire (7) is preferably 0.05 to 0.35 mm, and more preferably 0.08 to 0.15 mm. If the diameter is less than 0.05 mm, there is a risk of breaking when knitting, and if it exceeds 0.35 mm, knitting becomes difficult, which is not preferable in either case.

As the reinforcing wire (7), it is also possible to use two types of metal wires, a hard metal wire and a soft metal wire. In this case, two types of metal wires may be overlapped or twisted to form one, and this may be used as a knitting yarn that covers the outer surface of the first thread-like body (6).
As the hard metal wire, one having a Brinell hardness of 90 to 240 (kg / mm ² ) is used.
A metal material having such hardness has high mechanical strength such as tensile strength at high temperatures, and also has a high fatigue limit against repeated loads. Further, the metal having such hardness is unlikely to creep at a high temperature.
Accordingly, the hard metal wire can improve the mechanical strength of the packing and also improve the creep resistance under high temperature so that stress relaxation does not occur in the packing.

Examples of the hard metal wire include stainless steel, inconel, nickel, and nickel alloy.
The diameter of the hard metal wire is preferably 0.05 to 0.35 mm. If the diameter is less than 0.05 mm, there is a risk of breaking when knitting, and if it exceeds 0.35 mm, knitting becomes difficult, which is not preferable in either case.

As the soft metal wire, one having a Brinell hardness of 40 to 55 (kg / mm ² ) is used.
Since the metal material having such hardness is lower in hardness than the counterpart material with which the packing contacts, the counterpart material is not damaged when the packing is displaced relative to the counterpart material. Further, the metal material having such hardness is excellent in flexibility and can be easily plastically processed.
Therefore, the larger the proportion of the soft metal wire, the easier the knitting with the reinforcing wire (7). Moreover, when the packing material made from the 2nd thread-like object (8) obtained by knitting is pressure-molded and made into a packing, it can be set as the packing with which the surface and the inside were densely packed.

Further, the metal material having such hardness has good conformability to the counterpart material. Therefore, the sealing ratio of the packing can be improved as the proportion of the soft metal wire is larger.
Furthermore, the metal material having such hardness is not easily altered at a temperature of about 400 to 850 ° C. Therefore, the sealing performance of the packing can be stabilized at a high temperature.

Examples of the soft metal wire include copper alloys such as copper and monel metal, aluminum, and aluminum alloys.
The diameter of the soft metal wire is preferably 0.05 to 0.35 mm. If the diameter is less than 0.05 mm, there is a risk of breaking when knitting, and if it exceeds 0.35 mm, knitting becomes difficult, which is not preferable in either case.

When using two types of metal wires, a hard metal wire and a soft metal wire, as the reinforcing wire (7), the ratio of the number of both is preferably 1: 1 to 0.3. When this is expressed as a ratio value (number of hard metal wires / number of soft metal wires), it is 1 to about 3.3.
If the ratio value is less than 1, the mechanical strength of the second filamentous body (8) becomes low. Conversely, if it exceeds 3.3, the knitting process becomes difficult and the conformability of the second filamentous body decreases. In any case, the sealing performance of the packing may be lowered, which is not preferable.

It is preferable that the stitch pitch of the reinforcing wire (7) knitted so as to cover the outer surface of the first filament (6) is 1.5 to 6 mm in the length direction and the width direction, respectively.
If the pitch of the stitch of the reinforcing wire (7) is less than 1.5 mm, the expanded graphite is difficult to enter into the mesh, so that the conformability and sealability of the packing cannot be obtained sufficiently. In either case, the strength decreases, which is not preferable.

The knitting method (knitting structure) of the reinforcing wire (7) may be warp knitting or weft knitting, but weft knitting is preferred from the viewpoint of strength.
In the case of weft knitting, the specific form is not particularly limited, and round knitting, square knitting, flat knitting, rubber knitting, pearl knitting, tuck knitting, float knitting, one-sided knitting, two-sided knitting, two-sided knitting, lace Forms such as knitting and splicing knitting can be employed.

In the present invention, the second filament (8) is preferably impregnated or coated with the lithiated swellable clay material.
As the swellable clay material, those described above are preferably used.
More specifically, all or part of the interlayer cations of smectite (preferably montmorillonite or stevensite) such as montmorillonite, beidellite, saponite, hectorite, stevensite, and soconite are replaced with lithium ions and Heat-treated (ie, lithiated).

  In the heat treatment, for example, the second filament (8) is added to a lithium compound in an aqueous dispersion of a swellable clay material, whereby all or part of interlayer cations are replaced with a lithium material (12 ) (See FIG. 2).

  The second expansion in the form of a band so as to cover the periphery of the second filament (8) (preferably impregnated or coated with a lithiated swellable clay material). A graphite tape (9) is wound (see FIG. 2). Thereby, the packing material which concerns on this invention is obtained.

As the second expanded graphite tape (9), the same as the first expanded graphite tape (2) described above can be used.
It is preferable that the second expanded fiber (13) is included in the second expanded graphite tape (9).
Carbon fibers are preferably used as the second reinforcing fibers (13), but other organic fibers and inorganic fibers can also be used. For example, synthetic resin fibers such as aramid fibers, metal fibers made of stainless steel (SUS304, SUS316, SUS316L, etc.) or Inconel, inorganic fibers such as glass fibers, and cotton yarn can be used.
When using carbon fiber, it is preferable to use the above-described spread fiber bundle. The spread fiber bundle can serve to reinforce the second expanded graphite tape (9) and supplement the elasticity that tends to be insufficient in the expanded graphite tape.

In the present invention, the second expanded graphite tape (9) is preferably impregnated or coated with the lithiated swellable clay material.
As the lithiated swelling clay material, those described above are preferably used.
Specifically, all or a part of interlayer cations of smectite (preferably montmorillonite or stevensite) such as montmorillonite, beidellite, saponite, hectorite, stevensite, and soconite are replaced with lithium ions and heated. It has been treated (ie lithiated).

  The heat treatment may be performed after the second expanded graphite tape (9) is immersed in the clay material (12), or a clay film is prepared from the clay material (12), and the heat treatment is performed. The later clay film may be laminated on one side or both sides of the second expanded graphite tape (9).

In the present invention, as described above, the core material (5), the first reinforcing fiber (3), the first expanded graphite tape (2), the second filament (8), and the second expanded graphite tape (9). A configuration in which at least one of them is impregnated or coated with a lithiated swelling clay material is preferably employed.
When this configuration is employed, the lubricating oil and the rust preventive oil are retained between the layers of the swellable clay material, thereby exhibiting excellent lubricity (low torque property) and corrosion resistance under high temperature and high pressure conditions. In addition, the lithiated swellable clay material is excellent in water resistance because it is not dispersed by water. Furthermore, the high heat resistance of the swellable clay material can improve the heat resistance of the packing material.

The gland packing according to the present invention is obtained by braiding the above-described packing material and press-molding the braided body into a predetermined shape.
More specifically, by braiding the packing material described above, it is possible to configure a braided string such as a braided string such as a circular braided string or a square braided string, or a striking string such as a round punched string or a square punched string. . In addition, a string body in the form of a bag-like string or a fixed string can also be configured. It should be noted that in the case of a striking string, arbitrary striking methods such as four striking, eight striking, sixteen striking, eighteen striking, twenty-four striking, thirty-two striking are possible. 4 (a) to 4 (d) are diagrams showing an example of a string (15) obtained by braiding the packing material according to the present invention.

The gland packing (10) according to the present invention is obtained by pressure-molding the above-described string body (15), and is formed in a ring shape, for example, as shown in FIG. Such a gland packing (10) is packed in a stuffing box and can be used for shaft sealing of a fluid device.
In particular, since the gland packing (10) according to the present invention can harmonize heat resistance, durability, sealability, lubricity (low torque property), and compression recovery property at a high level, It is a gland packing suitable for use under high pressure and high temperature conditions such as in a nuclear power plant.

  The present invention can be suitably used as a gland packing for sealing a valve shaft under high pressure and high temperature conditions such as a thermal power plant and a nuclear power plant.

DESCRIPTION OF SYMBOLS 1 Packing material 2 1st expanded graphite tape 3 1st reinforcement fiber 4 Laminated tape 5 Core material 6 1st filamentous body 7 Reinforcement wire 8 2nd filamentous body 9 2nd expanded graphite tape 10 Ground packing 11 Lithified swelling property Clay material 12 Clay material (all or part of the interlayer cations are replaced with lithium ions by adding lithium compounds to the aqueous dispersion of swellable clay material)
13 Second reinforcing fiber 14 Adhesive layer 15 String body

Claims (12)

  The strip-shaped first expanded graphite tape is twisted so as to cover the core material to form a first thread, and a reinforcing wire is knitted so as to cover the periphery of the first thread, to form a second thread, A packing material obtained by winding a band-shaped second expanded graphite tape so as to cover the periphery of the second filamentous body.   A laminated tape obtained by laminating a strip-shaped first expanded graphite tape and one or more first reinforcing fibers is twisted so as to cover the core material to form a first thread-like body, and the periphery of the first thread-like body is formed. A packing material, wherein a reinforcing wire is knitted so as to be covered to form a second thread, and a band-shaped second expanded graphite tape is wound so as to cover the periphery of the second thread. The core material is impregnated or coated with a swellable clay material,
The packing material according to claim 1 or 2, wherein the swellable clay material is subjected to heat treatment in which interlayer cations are replaced with lithium ions.   The packing material according to any one of claims 1 to 3, wherein the first reinforcing fiber is impregnated or coated with the swellable clay material.   The packing material according to any one of claims 1 to 4, wherein the swellable clay material is impregnated or coated on the first expanded graphite tape.   The packing material according to any one of claims 1 to 5, wherein the second clay is impregnated or coated with the swellable clay material.   The packing material according to any one of claims 1 to 6, wherein the swellable clay material is impregnated or coated on the second expanded graphite tape.   The packing material according to any one of claims 1 to 7, wherein the second expanded graphite tape includes second reinforcing fibers.   The packing material according to any one of claims 1 to 8, wherein the core material is made of stainless steel or Inconel.   The packing material according to claim 1, wherein the reinforcing wire is made of stainless steel or Inconel.   The packing material according to claim 8, wherein the second reinforcing fiber is made of carbon fiber.   A gland packing formed by braiding the packing material according to claim 1 and press-molding the braided body into a predetermined shape.

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