JP2001330154A - Ring packing made of expansion graphite and its manufacturing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a ring packing made of expansion graphite to prevent oxidation and extinction of the expansion graphite even in a temperature region exceeding an application limit temperature and be capable of maintaining excellent sealing ability and also prevent protrusion of the expansion graphite due to fastening and to provide its manufacturing method. SOLUTION: A metal foil 2 is nipped between the end face parts in the direction of width of an expansion graphite tape 1 to form a covering member. After the graphite tape with the covering member is wound in a laminating state in a given thickness around the periphery of a mold A1, pressure molding is effected by a mold A3 to constitute the ring packing made of expansion graphite.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an expanded graphite ring packing suitable for sealing a fluid such as gas or water for use in a valve or the like of a high-temperature and high-pressure apparatus, and to an improvement in a method of manufacturing the same.

[0002]

2. Description of the Related Art Conventionally, a metal seal ring has been known as a seal ring used for a valve of a high-temperature and high-pressure apparatus. In the case of this metal seal ring, if the seal portion is damaged during maintenance of the device, polishing and cutting must be performed to repair the damage, which increases maintenance costs. Would.

[0003] Therefore, as an alternative to a metal seal ring, a ring packing made of a soft and highly sealable expanded graphite is often used. There are various types of this expanded graphite ring packing, and the most common type is called a tape mold type, and a tape-shaped material obtained by slitting an expanded graphite sheet into a predetermined width is placed in a molding die. This is a ring-shaped packing obtained by spirally or concentrically winding and arranging, and then press-molding this in the tape width direction.

The expanded graphite ring packing has no risk of damaging the seal portion and is highly resilient, so that it can follow pressure fluctuations more sufficiently than a metal seal ring and has a sufficient tightening pressure even at a low tightening pressure. It has the advantage of exhibiting sealing properties. Further, a composite structure in which a metal foil, a wire mesh, or the like is buried as a reinforcing material inside the expanded graphite may be used.

[0005]

However, the ring packing made of expanded graphite has a drawback that in a temperature range exceeding 400 ° C., the expanded graphite is oxidized and disappeared by oxygen in the atmosphere, and it is difficult to maintain the sealing property. Also, in the case of a fluid containing oxygen, the expanded graphite is similarly oxidized and disappeared in a temperature range exceeding 400 ° C., making it difficult to maintain the sealing property. further,
In the case of using only the expanded graphite, the expanded graphite may protrude from the gap when fastened and fixed. As a result, there is a problem that the sealing performance is reduced due to stress relaxation.

In order to solve the problem of the expanded graphite ring packing, Japanese Patent Application Laid-Open No. H10-4710 discloses an example.
As described in JP-A-489, a metal grommet is applied to one end surface (atmosphere side) and a hunted metal is applied to the other end surface (fluid side) of an expanded graphite ring packing formed by a tape mold method. What has been press-bonded by pressure molding has been proposed.

The expanded graphite ring packing having the above structure is effective in preventing the expanded graphite from protruding around the seal. However, the ring packing between the inner peripheral surface of the pressure vessel, the outer peripheral surface of the lid shaft and the expanded graphite tape is effective. Gaps are generated, and the invasion of air from the atmosphere side cannot be prevented, the volume of the expanded graphite molded body is reduced by high-temperature oxidation, and the temperature exceeds the usage limit temperature of expanded graphite of 400 to 450 ° C. There is a disadvantage that it cannot withstand use at high temperatures.

According to the present invention, there is provided an expanded graphite ring packing which does not lose oxidation of expanded graphite even in a temperature range exceeding a service limit temperature, can maintain excellent sealing properties, and does not protrude from expanded graphite by tightening. The main purpose is to provide a manufacturing method thereof.

[0009]

In order to achieve the above object, an expanded graphite ring packing according to the first aspect of the present invention is an expanded graphite ring packing formed by winding an expanded graphite tape into a ring shape. The gist of the invention is that at least one of the end surfaces or both end surfaces of the ring packing is provided with a covering member made of at least a metal foil as a member for preventing oxidation and disappearance of the expanded graphite.

The expanded graphite ring packing according to the second aspect of the present invention is characterized in that, in the first aspect, a metal foil is sandwiched between one end face or both end faces in the width direction of the expanded graphite tape to form a covering member. The main point is.

An expanded graphite ring packing according to a third aspect of the present invention is a tensioned graphite ring packing formed by winding an expanded graphite tape in a ring shape and having a soft core material on one end face or both end faces. The gist is that a covering member formed by forming a string-like body whose surface is covered with a metal foil into a ring shape is overlapped.

Further, according to a fourth aspect of the present invention, there is provided a method for manufacturing an expanded graphite ring packing, wherein one end face or both end faces of the expanded graphite tape is sandwiched between metal foils to form a covering member. Is wound in a spiral or concentric shape, and then put into a molding die and pressed in the width direction of the tape to form a ring.

According to a fifth aspect of the present invention, there is provided a method for manufacturing an expanded graphite ring packing, comprising the steps of: forming an expanded graphite ring packing formed by winding an expanded graphite tape into a ring; The gist is that a covering member formed by forming a string-like body in which the surface of a core material is covered with a metal foil into a ring shape is overlapped, placed in a molding die and crimped.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS As a preferred embodiment of the present invention, as shown in FIGS. 1A to 1E, a metal foil 2 is provided on one end face or both end faces in the width direction of an expanded graphite tape 1. the sandwiched thereby, which covering members and without preventing the oxidation loss of expanded graphite, swirl until the covering member with the expanded graphite tape 1, as shown in FIG. 3, a predetermined thickness around the mold a ₁ piled up on Jo or concentrically, it was placed in a mold a _2, a mold a ₃ and pressed into the width direction of the tape constituting the expanded graphite ring packing a rectangular cross section.

[0015]

1 to 3 show an embodiment of the present invention. 1 (a) to 1 (e) show various structures of a covering member in which a metal foil 2 is sandwiched between one end face or both end faces in the width direction of an expanded graphite tape 1 to prevent oxidation and disappearance of the expanded graphite tape. An example is shown. After the metal foil 2 is sandwiched between the expanded graphite tapes 1, as shown in FIG. 2, for example, the metal foils 2 are applied to a pair of molding rolls 3 and 3 so that the metal foils are bitten into the soft expanded graphite tape and held so as not to fall off the tape. It is preferable to keep it.

[0016] Thus expanded graphite tape coated with metal foil, as shown in FIG. 3, wound superposed in a spiral or concentric shape until a predetermined thickness around the mold A _1, it into a mold after turning, by pressure forming in the width direction of the tape in the mold a _3, expanded graphite ring packing square cross section coated with the end face of a metal foil can be obtained.

By the above-described pressure molding, the wound expanded graphite tapes are firmly adhered to each other at the contact surface portion of the expanded graphite where no metal foil is present, and are integrated.

The structure examples (A) to (E) in FIG. 1 have a structure in which the contact surface for closely bonding and integrating the expanded graphite tapes is left as large as possible and the effect of preventing the disappearance of the expanded graphite tape from being oxidized is minimized. This is an example.

Among the above structural examples, structural examples (c) and (d)
Means that one of the metal foils sandwiched between the expanded graphite tapes is shorter than that of the structural examples (A) and (B). The structure is made as small as possible so that the same covering effect as in the structural examples (A) and (A) can be obtained. The metal foil used in the present invention has a melting point exceeding 400 ° C., is softer than the main body of the valve or the like, and preferably has a thickness of 0.05 mm or less. For example, aluminum, copper, iron, nickel, etc. are used. it can.

In addition, wrinkles generated in the metal foil at the time of pressure molding of the expanded graphite tape, an inorganic filler as a filler,
It is preferable to apply a binder or oil mixed with fine metal powder. As inorganic fillers, mica, clay, talc, barium sulfate, sodium bicarbonate, graphite,
Lead sulfate, trifolite, wollastonite and the like can be used.
As the binder, an inorganic binder, a rubber liquid or the like can be used. The mixing amount of the inorganic filler and the metal fine powder is preferably in the range of 20 to 80% by weight based on the binder.

FIGS. 4A to 4K and FIGS. 5A to 5H show various structural examples (in cross section) of a ring packing using the expanded graphite tape covered with the metal foil as described above.
Shown in The structural examples (f) to (g) in FIG. 4 are expanded graphite ring packings having a square cross-section, and the structural examples (c) to (h) in FIG. 5 are expanded graphite ring packings having a wedge-shaped cross section. is there.

The structural examples (C), (K), (S), (S), (T), and (H) of the structure examples of FIGS.
There is a tape portion without metal foil on the end face of the expanded graphite tape to be coated, but this is configured on the assumption that it will be covered with a member such as a retainer ring used jointly when loading the ring packing. Things.

FIG. 6 shows an example in which the above-mentioned expanded graphite ring packing having a rectangular cross section is used for sealing the body and lid of a pressure vessel. FIG. 7 shows an expanded graphite ring packing having a wedge-shaped cross section being used for a pressure vessel. The example used for sealing a container and a lid is shown.

6 to 7, reference numeral 4 denotes a body of the pressure vessel, 5 denotes a lid, 6 denotes a tension bolt, 7 denotes a retainer ring, and a ring packing made of expanded graphite has a metal foil-covered member facing the atmosphere. Then, it is loaded between the container and the lid, fixed by the retainer ring 7 and tightened by the operation of the tension bolt 6.

Then, the covering member of the ring packing made of the expanded graphite tape 1 and the metal foil 2 is deformed by the tightening force of the tension bolts 6, and the ring packing comes into close contact with the inner peripheral surface of the container 4 and the outer peripheral surface of the lid 5, A sealing function is provided between the two. Since the covering member made of the metal foil has a function of controlling the protrusion of the expanded graphite, the protrusion to the gap between the outer peripheral surface of the container body 4 and the outer peripheral surface of the retainer ring 7 is effectively prevented,
Therefore, the sealing function is favorably maintained for a long time.

Further, even if air on the atmospheric side tries to enter the ring packing through the gap, there is a possibility that the infiltration of the air is prevented by the covering member made of metal foil and the expanded graphite forming the ring packing is oxidized and disappears. Resolved, 4
High sealing properties are exhibited over a long period of time even under operating conditions exceeding 00 ° C.

Example 1 An expanded graphite tape having a thickness of 0.83 mm and a width of 16 mm and a metal foil tape having a thickness of 0.01 mm and a width of 12 mm were used as raw materials, as shown in FIG. At the both end portions in the width direction of the above, an expanded graphite tape as a covering member was sandwiched with a metal foil tape so as to have a short portion of 4 mm and a long portion of 8 mm, and a ring packing having a square cross section formed by winding and pressing was used as a sample. Was mounted on the lid sealing portion of the pressure vessel, and the result of confirming the change in weight is shown in Table 1 below in comparison with a ring packing made of only expanded graphite. Here, as the acceleration test, the standard clearance in which the clearance between the pressure vessel and the lid is generally a loose fit of JIS B0401, and 0.1 mm larger than that, and the test temperature is increased by 65%
The example at the time of 0 degreeC is shown.

[0028]

[Table 1]

As is clear from the results shown in Table 1, it was confirmed that the products of Examples had little loss of heat even when the gap on the atmosphere side was standard or enlarged, and the oxidation of expanded graphite was effectively prevented. Further, the product of the example was subjected to a water pressure resistance test of 100 MPa, and as a result, it was confirmed that there was no leakage as in the case of only the expanded graphite tape.

According to the configuration of the expanded graphite ring packing of the above embodiment, in the expanded graphite ring packing formed by winding the expanded graphite tape in a ring shape, the metal foil is attached to the end face in the width direction of the expanded graphite tape. With a simple structure that sandwiches the expanded graphite, it is possible to maintain excellent sealing properties without extinguishing the expanded graphite even in a temperature range exceeding 400 ° C, there is no protrusion of the expanded graphite due to tightening, and a metal backup ring is also required An expanded graphite ring packing can be obtained.

In addition, according to the configuration of the above-described embodiment, it is possible to provide an expanded graphite ring packing which can easily be a substitute for a metal seal ring even in an existing device corresponding to a conventional metal seal ring. it can.

FIGS. 8 (T) to (N) to FIGS. 9 (N) to (C)
Next, another embodiment of the present invention will be described. In the figure, P is an expanded graphite packing formed by winding the expanded graphite tape 1 in a ring shape, and Q is a metal foil packing formed by winding the metal foil tape 2 in a ring shape. A ring-shaped metal foil packing Q is superimposed on one end face or both end faces of the expanded graphite packing P as a coating member for preventing the disappearance of the expanded graphite packing P by oxidation.

The expanded graphite-based packing P is obtained by wrapping an expanded graphite tape spirally or concentrically around a mold and pressing the tape in the width direction of the tape, as in the above-described embodiment. The metal foil packing Q is also obtained by molding in the same manner as the expanded graphite packing P.
It is preferable that the expanded graphite-based packing P and the metal foil-based packing Q superimposed on the expanded graphite-based packing P are put into a mold again, pressurized, and press-bonded to each other.

The expanded graphite-based packing P and the metal foil-based packing Q may be overlapped on a plane as shown in FIGS. 8 (T) and 9 (D). G) and FIGS. 9 (no) and 9 (c), as shown in FIG.
A stronger coupling force can be obtained by fitting in the form.

FIGS. 10 to 11 show another embodiment of the metal foil packing. The metal foil-based packing of the present embodiment is obtained by press-molding a string-like body in which the surface of a soft core material R is covered with a metal foil tape 2 into a ring shape using a mold. The soft core material R of the metal foil-based packing is formed by knitting an expanded graphite tape with a metal fiber as a knitting yarn, knitting the knitting yarn into eight knits, bag knitting or the like, organic fiber, rubber, A rod-shaped molded product obtained by molding a kneaded product obtained by kneading a filler into a rod shape is used.

In addition, a bundle obtained by bundling a plurality of wires can be used as the core material. Necessary as a wire material is a heat-resistant synthetic resin fiber such as aramid fiber impregnated with lubricating oil, or a sealing material such as metal such as Monel metal, Inconel, stainless steel, copper, or aluminum, carbon fiber, glass fiber, or ceramic fiber fiber. Any material can be suitably used without particular limitation as long as the material has excellent heat resistance and strength.

The diameter of the wire is desirably 3 mm or less from the viewpoint of manufacturing. As the wire material, a wire material obtained by bundling a plurality of wire materials or a wire body obtained by bundling and knitting or assembling one wire material is suitably used.

Specifically, for example, a circular braid formed of a plurality of wires, a braid such as a square braid, a round braid, a square braid, and the like are preferably exemplified. Alternatively, a wire obtained by bundling a plurality of wires as they are and twisting them can also be suitably used.

The linear body is entangled to form a structure. The shape of the cross section is not particularly limited as long as it can be entangled, and examples thereof include a circle, a square, and an ellipse. In this case, the cross section is preferably 0.05 to 0.5 mm. As a method for confounding the linear body, a method used for general packing may be applied, and examples thereof include knit knitting, bag knitting, and twisting.

A metal foil tape is wound around the surface of the wire bundle as described above. The winding method is not particularly limited,
Single or double or more may be sequentially wound around the string-like surface, or the surface of the wire bundle is covered with a metal foil tape, and both the metal foil tape and the wire bundle are twisted while twisting, Such as winding a metal foil tape around the wire surface
An appropriate method can be adopted. In the latter winding method,
A wire bundle and a metal foil tape in which both are twisted are obtained.

[0041]

As described in detail above, according to the present invention,
It is possible to provide an expanded graphite ring packing that does not lose oxidation of expanded graphite even in a temperature range exceeding a use limit temperature, can maintain excellent sealing properties, and does not protrude from expanded graphite due to tightening, and a method of manufacturing the same. it can.

[Brief description of the drawings]

FIG. 1 shows one embodiment of the present invention and is a cross-sectional view of various structural examples in which an end face of an expanded graphite tape is covered with a metal foil.

FIG. 2 is an explanatory view showing means for holding a metal foil on an expanded graphite tape.

FIG. 3 is an explanatory diagram of winding an expanded graphite tape covered with a metal foil and press-molding the expanded graphite tape into a ring shape using a mold.

FIG. 4 is a cross-sectional view showing various structural examples of a ring packing having a rectangular cross section formed using an expanded graphite tape.

FIG. 5 is a cross-sectional view showing various structural examples of a ring packing having a wedge-shaped cross section formed using an expanded graphite tape.

FIG. 6 is a sectional view of a pressure vessel loaded with a ring packing made of expanded graphite having a square cross section.

FIG. 7 is a cross-sectional view of a pressure vessel loaded with a ring packing made of expanded graphite having a wedge-shaped cross section.

FIG. 8 shows another embodiment of the present invention, and is a cross-sectional view showing various structural examples of an expanded graphite ring packing having a square cross section in which an end face of the expanded graphite packing is covered with a metal foil packing.

FIG. 9 is a cross-sectional view showing various structural examples of an expanded graphite ring packing having a wedge-shaped cross section in which an end surface of the expanded graphite packing is covered with a metal foil packing.

FIG. 10 is a partial perspective view of a packing formed into a cord-like body, showing another embodiment of the metal foil packing.

FIG. 11 is a partial perspective view of a ring-shaped metal foil packing.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Expansion graphite tape 2 Metal foil 3 Molding roll 4 Body of pressure vessel 5 Lid 6 Tension bolt 7 Retainer ring P Expansion graphite packing Q Metal foil packing R Core material

 ────────────────────────────────────────────────── ─── Continuing from the front page (72) Inventor Mitsuru Takahira 2-2-18 Harayama, Urawa-shi, Saitama F-term in Urawa Plant, Nippon Leakless Industry Co., Ltd. (Reference) 3J040 AA01 AA13 BA01 EA15 EA17 EA47 FA11 HA01 HA15 3J043 AA01 AA11 AA15 BA06 CA13 CB18 CB21 DA11 4G046 EC01 EC05 EC08 4H017 AA23 AA29 AC13 AC16 AD01 AE02

Claims (5)

[Claims] 1. A ring packing made of expanded graphite formed by winding an expanded graphite tape into a ring shape and forming a member on one end surface or both end surfaces of the ring packing as a member for preventing the disappearance of oxidation of the expanded graphite. A ring packing made of expanded graphite, characterized in that at least a covering member made of a metal foil is provided. 2. The expanded graphite ring packing according to claim 1, wherein a metal foil is sandwiched between one end face or both end faces in the width direction of the expanded graphite tape to form a covering member. 3. A ring-shaped body in which the surface of a soft core material is covered with a metal foil on one end surface or both end surfaces of an expanded graphite ring packing formed by winding an expanded graphite tape into a ring shape. The expanded graphite ring packing according to claim 1, wherein the covering members formed into a shape are overlapped. 4. An expanded graphite tape having one end face or both end faces sandwiched between metal foils to form a covering member.
The expanded graphite tape with the covering member is wound spirally or concentrically, and then put into a molding die, and is pressed in the width direction of the tape to form a ring shape. Packing manufacturing method. 5. An expanded graphite ring packing formed by winding an expanded graphite tape into a ring and forming a ring on one end or both end surfaces of a soft core material covered with metal foil. A method of manufacturing a ring packing made of expanded graphite, comprising laminating covering members formed in a shape, placing them in a molding die and pressing them together.