JPH069942A - Spiral gasket - Google Patents

Abstract

PURPOSE:To obtain a spiral gasket which can satisfactorily seal the sealed surface of a flange when the sealed surface is nonplanar, for example, conical or semispherical as well as when it is planar. CONSTITUTION:The gasket is produced by integrally superposing metallic hoops 2 in the form of a flat strip and fillers 3 in the form of a tape slightly wider than that into a spiral capable of being deformed in its axial direction and capable of being deformed into a nonplanar surface, e.g. a conical surface at its ends 1a and 1b. The filler 3 consists of at least one sheet material selected from among an inorganic paper consisting mainly of an inorganic filler containing sepiolite and an inorganic powder, an expanded graphite sheet formed by aggregating expanded graphite particles and a tetrafluoroethylene resin sheet made porous by stretching.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a spiral gasket mounted between opposed flange seal faces in a flange joint structure for general industrial piping equipment other than automobile exhaust pipe systems.

[0002]

2. Description of the Related Art In general, a conventional spiral gasket (hereinafter referred to as "conventional gasket") 21 comprises a metal hoop 22 having a corrugated cross-sectional shape in the width direction and an expanded graphite tape, as shown in FIG. 7 (A). It is formed by polymerizing and integrating with an inorganic filler 23 in a spiral shape. Due to the presence of the metal hoop 22, it has excellent compression recovery properties and the like, and is optimal as a seal between flanges.

By the way, in the flange joint structure in which the seal member is loaded between the flanges, the flange seal surface for sandwiching the seal member has traditionally been made into a flat shape, but recently, it has been polluting the global environment. Due to demands for prevention and safety, the flange sealing surface is often made non-planar such as a conical surface or a hemispherical surface.

[0004]

However, in the conventional gasket 21, the flange sealing surface has a non-planar shape such as a conical surface or a hemispherical surface regardless of the traditional planar shape of the flange sealing surface. Cannot exhibit a good sealing function, and cannot be used at all in a flange joint structure having such a flange sealing surface.

That is, in this conventional gasket 21, the annular annular layers of the hoop 22 and the filler 23 are engaged with each other in a corrugated form, and the rigidity against axial deformation is extremely high. End face of gasket (hereinafter referred to as "seal face contact face") 21
It is not easy to deform a and 21b from a flat state orthogonal to the axial direction. Moreover, when it is compressed and deformed in the axial direction, as shown in FIG. 7B, the flow of the filler 23 to the bent portion is not smoothly performed, and a gap 24 is formed between the filler 23 and the so-called leak path. Easy to do.

Therefore, when loaded between non-planar flange seal surfaces such as a conical surface, the seal surface contact surfaces 21a and 21b are unlikely to be deformed into a rotational surface shape corresponding to the flange seal surface, and it is impossible. When deformed to, abnormal deformation occurs between the fillers and the gap 24 is remarkably generated, and a good sealing function cannot be exhibited at all. Of course, even if the gasket end surface is previously manufactured and molded into a conical surface shape or the like corresponding to the flange seal surface shape, the abnormal deformation and the generation of the gap as described above cannot be avoided, and the good sealing function is exerted. I don't get it.

In view of such a point, the present invention has a spiral gasket as an inter-flange seal not only when the flange sealing surface has a planar shape but also when it has a non-planar shape such as a conical surface or a hemispherical surface. An object of the present invention is to provide a spiral gasket that can exhibit a good sealing function without impairing its original excellent function.

[0008]

A spiral gasket according to the present invention, which has solved this problem, has a flat band plate-shaped metal hoop and a tape-shaped filler, and the gasket end face has a shape corresponding to a flange sealing surface. In order to be deformable in the axial direction so as to be polymerized and integrated in a spiral shape, further, a filler, inorganic paper containing inorganic fibers containing sepiolite and inorganic powder as a main component, expanded graphite particles The present invention proposes that the expanded graphite sheets are aggregated and one or a plurality of types of sheet materials selected from a porous tetrafluoroethylene resin sheet that is made porous by stretching are proposed.

[0009]

[Function] Since both the hoop and the filler are flat plate shapes which are straight in the axial direction, when an external force in the axial direction is applied,
A slippage occurs between the two and they are deformed in the axial direction, and the seal surface contact surface, which is the gasket end surface, can be formed into any shape such as a flat surface, a conical surface, or a hemispherical surface. Therefore, when the gasket is loaded between the flange seals and the pressure is applied, even if the flange seal surface has a non-planar shape such as a conical surface or a hemispherical surface, the seal surface contact surface will adapt and deform to the flange seal surface. , It is possible to make proper contact with the flange sealing surface. At this time,
Since the hoop and the filler do not have a bent portion like the conventional gasket, the filler flows smoothly during the axial deformation, and a gap is not formed between the hoop and the filler. Moreover, when the hoop is deformed in the axial direction as described above, the hoop is reduced in diameter accordingly, that is, the hoop is reduced in diameter so as to compress the filler in the radial direction. Therefore, the gasket density is increased. In particular, when the flange sealing surface has a shape that inclines toward the center like a conical surface or a hemispherical surface, tighten the gasket to
A component force for compressing the gasket toward the center acts on the gasket end, and the hoop collapses toward the center. As a result, the filler is further compressed, and the adhesion between the hoop and the filler or the gasket density is significantly increased.

Therefore, not only when the flange sealing surface has a planar shape but also when it has a non-planar shape such as a conical surface or a hemispherical surface, the inter-flange sealing can be satisfactorily performed with a low tightening surface pressure. .

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The structure of the present invention will be specifically described below based on the embodiments shown in FIGS.

The spiral gasket 1 of this embodiment is shown in FIG.
Alternatively, as shown in FIG. 4, the flat hoop-shaped metal hoop 2 and the tape-shaped filler 3 are spirally polymerized and integrated.

The hoop 2 is made of a thin metal plate material such as stainless steel. The hoop 2 is longer than the filler 3, and the winding start portion 2a and the winding end portion 2b are wound a plurality of times and then spot welded at a plurality of positions. The number of turns of the hoop end portions 2a and 2b is mainly determined by the fact that sufficient rigidity in the axial direction of the gasket 1 is obtained in relation to the tightening surface pressure, and that the filler is deformed in the axial direction as described above. It is desirable to set it on the condition that the diameter of 3 can be reduced so as to be compressed.

The filler 3 is composed of one or a plurality of sheet materials selected from inorganic paper, expanded graphite sheets in which expanded graphite particles are aggregated, and porous tetrafluoroethylene resin sheet made porous by stretching. There is. In particular, as the above-mentioned inorganic paper, 36.5% by weight or more of fibrous substance (ceramic fiber 5 to 20% by weight, sepiolite (about 0.2 μm)
Α type having a fiber diameter of 13.5 to 2) is preferable.
5% by weight, organic fiber hemp such as pulp 1 to 10% by weight),
59 wt% or less (more preferably 45.5 to 59 wt%) talc mineral, inorganic powder such as calcium carbonate, clay, barium sulfate, etc., and 1 to 10 wt% natural rubber latex, synthetic rubber latex, resin emulsion Those composed of a binder such as

The constituent materials and thicknesses of the hoop 2 and the filler 3 are appropriately selected according to the conditions such as the gasket diameter and the properties of the sealed fluid.

The width a of the filler 3 is set so that the hoop 2 is not exposed on the seal surface contact surfaces 1a and 1b, which are the gasket end surfaces, even when the filler 3 is deformed into a telescope shape according to the flange seal surface shape. It is set to be slightly wider than the width b of 2 (see FIGS. 2 and 4). If the amount of protrusion (fluff amount) of the filler 3 from the hoop 2 is too small, the hoop 2 may come into contact with the flange sealing surface, and the hoop contact portion may form a leak path. If the amount of protrusion is too large, the fluffing portion of the filler 3 may fall off due to the sealed fluid pressure, high-temperature vibration, or the like, and in any case a good sealing function cannot be expected. Both a and b
It is necessary to determine the dimensions of the above in consideration of such points. Generally, the dimensions should be determined within the range of 1 <a / b ≦ 1.5 according to the sealing conditions such as the shape of the flange sealing surface. Is preferred.

The spiral gasket 1 thus constructed
Is capable of exerting a sealing function similar to that of the traditional spiral wound gasket described at the beginning because of its structure,
Since both the hoop 2 and the filler 3 have a flat plate shape that is straight in the axial direction, when an external force in the axial direction is applied in a flat configuration (a configuration in which the gasket end surfaces 1a and 1b are parallel flat surfaces) at the time of manufacture, both There was a slip between 3
It will be transformed into a telescope in the axial direction. That is, the seal surface contact surfaces 1a and 1b can be changed from a planar shape to an arbitrary shape such as a conical surface or a hemispherical surface.

Therefore, for example, as shown in FIG. 1 or 3, even in a flange joint structure in which the flange sealing surfaces 6a, 7a are conical or hemispherical, the inter-flange seal can be made to function well.

That is, the flange joint structure shown in FIG. 1 is provided in a general piping line.
Both pipes 4 and 5 are connected in a sealed state by fastening annular flanges 6 and 7 welded to the end of 5 with bolts 8 with the spiral gasket 1 interposed therebetween. An annular protrusion 6 ′ is provided on one flange 6.
Is formed so as to project, and the end surface of this projection 6 ′ is formed as a sealing surface 6 a forming a concave conical surface. The other flange 7 is provided with an annular groove 7'to which the projection 6'can be fitted, and the groove bottom surface is formed as a sealing surface 7a which forms a convex conical surface. Both flange sealing surfaces 6a, 7a are formed by a protrusion 6 '.
Are formed in a conical surface shape such that they are parallel to each other when fitted into the groove 7 '.

In this flange joint structure, when the flat gasket 1 is inserted between the sealing surfaces 6a and 7a and the flanges 6 and 7 are tightened, the tightening force is increased. Causes sliding deformation in the axial direction, so that the seal surface contact surfaces 1a and 1b become the seal surfaces 6a and 7a.
The shape is changed to a shape corresponding to, and finally, as shown in FIG. 2, the sealing surfaces 6a and 7a are entirely brought into contact with each other. In this way, the sealing surface contact surface 1a,
The flange sealing surface 6 having a conical surface shape is extremely deformable and familiar to the sealing surfaces 6a and 7a of 1b.
Good sealing can be achieved between a and 7a by a low tightening pressure.

Further, the flange joint structure shown in FIG. 3 is provided in a general piping line like the above flange joint structure, and the annular flanges 6 and 7 welded to the ends of the pipes 4 and 5 are By inserting the flat spiral coil 1 between the sealing surfaces 6a and 7a formed on the flanges 6 and 7 and having the same hemispherical shape, and fastening them with bolts 8 ... They are connected in a sealed state. Also in this case, similarly to the above, as the flanges 6 and 7 are tightened, the seal surface contact surfaces 1a and 1b are changed to the hemispherical shapes corresponding to the seal surfaces 6a and 7a, and FIG. As shown, the seal surfaces 6a and 7a are finally brought into full contact with each other, and a good sealing function can be exhibited.

By the way, the spiral gasket 1 according to the present invention can be used as it is in the flat form at the time of manufacture as described above. However, if necessary, the seal surface contact surfaces 1a and 1b can be replaced with the flange seal surface. 6A, 7a may be used after being preformed by a pressure molding machine or artificially into the shape of the rotating surface (for example, the shape shown in FIG. 2 or 4).

Further, although not shown, it is needless to say that even when the sealing surface has a flat shape, a good sealing function can be exhibited as in the case described above. In this case, the preforming is not necessary.

The present inventor conducted an experiment to confirm the sealing characteristics of the product of the present invention. That is, in the first experiment, as shown in FIG.
As shown in FIG. 5, a pressing base 11 is supported on a base 10 by a cylindrical frame 12 so as to be slidable in the vertical direction.
Using the test device formed on the conical surface of °, the present invention product and the conventional product are loaded between the upper and lower facing surfaces 10a and 11a, and the base 10 is pressed by the pressing base 11. Gasket 1 from through passage 10c formed in
Nitrogen gas G of 0.3 kgf / cm ² is supplied to the inner peripheral area of the cylindrical frame 12 to prevent leakage gas to the outer peripheral area of the gasket 1.
It was collected from the hole 12a of No. 12 and the amount (leakage amount) was measured.
Further, in the second experiment, although not shown,
Using a test apparatus in which the upper and lower facing surfaces of 0 and 11 are formed into horizontal surfaces, the present invention product and the conventional product are loaded between the upper and lower facing surfaces, and the amount of leaked gas is measured in the same manner as in the above experiment. did. Here, the product of the present invention is a SU having a width of 6 mm.
A hoop made of an S304 flat strip and a filler made of a ceramic mixed sheet having a width of 8 mm (inorganic fiber containing sepiolite and inorganic paper containing talc as a main component), an inner diameter of 43.8 mm, an outer diameter of 54.2 mm, a radial direction It is a spiral gasket having a thickness of 8 mm which is polymerized and integrated into a flat spiral shape. The product of the present invention is the same as the above spiral wound gasket except that an expanded graphite sheet is used as a filler material, and has an inner diameter of 43.8 mm and an outer diameter of 5
It is a spiral gasket manufactured in a flat shape with a thickness of 4.1 mm and a radial thickness of 8 mm. Furthermore, the product of the present invention is
Preform the above spiral wound gasket so that both end surfaces become conical surfaces of 45 ° (molding pressure 250 Kgf / cm ²
It is a spiral wound gasket that has been molded with a die. Also,
The conventional product is a traditional spiral gasket (inner diameter 43.5 mm, outer diameter 57 m) formed by shaping the width direction cross section into W shape.
m, radial thickness 4.85 mm).

The results of these experiments are as shown in FIG. 6, and when the flange sealing surface has a conical surface shape, the product of the present invention has a much better seal than the conventional product regardless of the presence or absence of preforming. It was confirmed that it exerts its ability. No particular difference was observed in compression characteristics and sealability depending on the presence or absence of pre-molding. However, when pre-molded products are used, the ease of fitting to the sealing surfaces 6a, 7a and the sealing characteristics at the time of low tightening are further improved. It turned out that it can be improved. Further, it was confirmed that the product of the present invention exhibits excellent sealing property as compared with the conventional product even when the flange sealing surface has a flat shape. In addition, in FIG.
○ △ ● □ shows the result of the first experiment, ○ means the product of the present invention, △
Indicates the measurement results of the present invention, ● indicates the present invention, and □ indicates the measurement results of the conventional product. Further, ⊚ indicates the result of the second experiment, ⊚ indicates the result of measurement of the product of the present invention, and ■ indicates the result of measurement of the conventional product. The tightening load in FIG. 6 is the load applied to the spiral gasket by the pressing force of the pressing table.

The present invention is not limited to the above-mentioned embodiments, but can be appropriately improved or modified within the range not departing from the basic principle of the present invention. For example, the spiral gasket 1 according to the present invention has a flange seal surface 6a,
In addition to the case where 7a is a flat surface, a conical surface, or a hemispherical surface, for example,
It can also be applied to a flange seal surface having a complicated rotating surface shape having a corrugated cross section. Further, the winding conditions (winding tightening degree, etc.) of the hoop 2 and the filler 3 are appropriately set according to the shape of the seal surface, the presence or absence of preforming, etc., but further improvement of the sealing property is expected depending on the conditions. It

[0027]

As can be easily understood from the above description, the spiral gasket of the present invention is deformable in the axial direction, and is highly deformable and familiar to the flange sealing surface. Therefore, not only when the flange sealing surface has a planar shape, but also when it has a non-planar shape such as a conical surface or a hemispherical surface, a good sealing function can be exhibited.
It is possible to sufficiently cope with the recent diversification of the flange shape.

[Brief description of drawings]

FIG. 1 is a vertical cross-sectional side view showing a flange joint structure in which a spiral gasket according to the present invention is loaded between conical surface-shaped flange sealing surfaces.

FIG. 2 is a detailed view showing an enlarged main part of the same.

FIG. 3 is a vertical cross-sectional side view showing a flange joint structure in which a spiral gasket according to the present invention is loaded between hemispherical flange seal surfaces.

FIG. 4 is a detailed view showing the main part in an enlarged manner.

FIG. 5 is a vertical sectional side view showing an experimental apparatus.

FIG. 6 is a graph showing experimental results.

FIG. 7 is a partially cutaway vertical side view showing a conventional gasket, FIG. A showing a state before tightening, and FIG. B showing a state after tightening.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Spiral type gasket, 1a, 1b ... Sealing surface contact surface (gasket end surface), 2 ... Hoop, 3 ... Filler, 6,
7 ... Flange, 6a, 7a ... Flange sealing surface.

Claims (1)

[Claims] 1. A spiral type gasket to be loaded between opposed flange sealing surfaces, wherein a flat strip plate-shaped metal hoop and a tape-shaped filler are formed such that the gasket end surface corresponds to the flange sealing surface. In order to be deformable in the axial direction, it is spirally polymerized and integrated, and the filler is an inorganic paper mainly composed of sepiolite-containing inorganic fibers and inorganic powder, and expanded graphite in which expanded graphite particles are aggregated and formed. A spiral gasket comprising a sheet and one or more sheet materials selected from a porous tetrafluoroethylene resin sheet made porous by stretching.