JP2002317874A - Spiral gasket - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the sealing function of a spiral gasket in a wide range from low pressure conditions to high pressure conditions, particularly, provide a good sealing function even in the low pressure conditions under which it is conventionally insufficient. SOLUTION: The spiral gasket formed in an annular shape and adapted to be mounted between opposed sealing surfaces for providing sealing function comprises a pressurized portion formed by rolling a hoop material and a filler material in layer and having both side faces in contact with the sealing surfaces and a hoop outer ring portion arranged on the outer periphery of the pressurized portion and formed by rolling a hoop material.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a spiral gasket, and more particularly, to a spiral gasket formed by superposing and winding a hoop material such as a stainless steel band material and a filler material such as non-asbestos paper tape. It is targeted.

[0002]

2. Description of the Related Art Spiral gaskets are used for sealing structures in various fluid devices and fluid devices, for example, to prevent leakage of gas passing through the inside of pipes at flange surfaces of various pipes.

The basic structure of a spiral gasket is such that a hoop material having a V-shaped or M-shaped cross section made of a thin stainless steel strip or the like and a filler material made of a non-asbestos paper tape or the like are spirally wound. .

When a spiral gasket is mounted between opposed sealing surfaces such as a pipe flange and a tightening force is applied between the sealing surfaces, the filler material and the hoop material are deformed in the width direction (gasket thickness direction), and the hoop is deformed. Due to the resilient repulsion of the material, both ends of the filler material are strongly in contact with the sealing surface. At the high surface pressure generated at this time, the contact point between the sealing surface and the spiral gasket is sealed, and leakage of fluid between the inner peripheral side and the outer peripheral side of the spiral gasket is prevented.

The spiral gasket is provided with a block-shaped annular inner ring or outer ring made of steel or the like on the inner or outer peripheral side of the gasket main body in which the filler material and the hoop material are superposedly wound and brought into contact with the sealing surface. Provision is being made.

[0006] The inner ring is said to have a function of preventing a chrysanthemum-shaped deformation in which the hoop material of the gasket main body buckles toward the inner diameter side by a tightening force applied to the spiral gasket. It is said that the outer ring suppresses the deformation of the hoop material of the gasket main body so as to expand toward the outer peripheral side, so that a large repulsive force acts on the sealing surface from the hoop material and the sealing function is enhanced.
The outer ring also performs an outer peripheral positioning function when the spiral gasket is mounted. Spiral gaskets without outer rings are usually
The gasket is mounted on the grooved flange, and the outer periphery of the gasket is positioned by the peripheral wall of the groove for accommodating the gasket. At the same time, the deformation of the gasket to the outer peripheral side is suppressed, and a repulsive force is applied to the sealing surface.

[0007] Japanese Patent Application Laid-Open No. H10-220583 discloses that an inner ring formed by winding a hoop material is provided.
It is described that the above-described buckling prevention function can be achieved with a structure that is less expensive than a block-shaped inner ring.

The applicant of the present patent application is Japanese Patent Publication No. 62-4 / 1987.
In Patent No. 581, at the inner and outer peripheral ends of a spiral gasket using aluminum as a hoop material having difficulty in welding,
A technology has been proposed in which a stainless steel tape having excellent weldability is wound around 1-3 times and welded to prevent the gasket from loosening. In order to provide an outer ring by this technique, a metal ring serving as an outer ring is fitted to the outer periphery of a stainless steel tape.

[0009]

Among the conventional spiral gaskets, the spiral gasket with the outer ring described above has an outer ring under operating conditions in which a relatively high tightening pressure, that is, a surface pressure is applied, so that the outer ring has a lower outer ring. Although the sealing performance is improved as compared with those having no inner ring or only the inner ring, there is a problem that a sufficient sealing function cannot be exerted under use conditions in which only a relatively low surface pressure is applied.

[0010] Spiral gaskets are widely used as high temperature and high pressure gaskets. In this case, a high fastening force is applied and a sufficiently high surface pressure acts. But,
For example, 150L with ANSI / ASME standard flange
In the low pressure class below b, in terms of flange rigidity and bolt strength, it is not possible to apply sufficient tightening surface pressure required for the spiral gasket with outer ring, and the sealing function becomes insufficient. Fluid leakage may increase.

In the low pressure class as described above, conventionally, a non-metallic sheet gasket such as a joint sheet is often used. However, materials such as asbestos used for the joint sheet are considered to be unfavorable in terms of environmental problems, and various alternatives to asbestos have been studied, but it is difficult to achieve sufficient performance at an appropriate cost. there were.

In recent years, there has been a demand for prevention of environmental pollution on a global scale, and regulations on the prevention of leakage of gas and the like in various devices and piping facilities have been strengthened. Therefore, it is strongly desired that the spiral gasket can exhibit sufficient performance as a gasket replacing the joint sheet in the low pressure class described above, and in all pressure classes from the low pressure class to the high pressure class, Further improvement in leakage prevention performance is desired.

It is an object of the present invention to improve the sealing function of a spiral gasket in a wide range from a low pressure class to a high pressure condition. In particular, it is an object of the present invention to exhibit a good sealing function even in a low-pressure class, which has not been able to exhibit sufficient performance with a conventional spiral gasket.

[0014]

SUMMARY OF THE INVENTION A spiral gasket according to the present invention is a spiral gasket which is annular and is mounted between opposing sealing surfaces to perform a sealing function, wherein a hoop material and a filler material are formed. It comprises a pressure receiving portion wound in a pile and having both side surfaces in contact with the sealing surface, and a hoop outer ring portion disposed on the outer periphery of the pressure receiving portion and wound with a hoop material.

[Hoop Material] As the hoop material of the hoop outer ring portion and the pressure receiving portion, one having basically the same material and structure as the hoop material of a normal spiral gasket is used.

As the material of the hoop material, SUS304,
Examples include stainless steel materials such as SUS304L, SUS316, and SUS316L, and simple metals and alloys such as aluminum, inconel, and hastelloy.

The thickness of the hoop material varies depending on conditions such as the size of the gasket, the intended use and the required performance, but is usually set in the range of 0.1 to 0.3 mm.

The cross-sectional shape of the hoop material is not only a curved line shape such as a V-shape or an M-shape, but also a curved shape such as an arc shape or a wavy shape, a shape where a straight line portion and a curved portion are combined, and the like. Can also be adopted.

The material, thickness and width of the hoop material can be changed between the hoop outer ring portion and the pressure receiving portion. Further, the same hoop material can be used for the hoop outer ring portion and the pressure receiving portion.

[Filler Material] As the filler material of the pressure receiving portion, a material having the same material and structure as the filler material of an ordinary spiral gasket is basically used.

Various synthetic resins and inorganic materials can be used as the filler material. For example, PTFE resin,
Examples include expanded graphite, asbestos, and non-asbestos inorganic materials. A combination of a plurality of materials may be used. The material of the filler material can be selected according to the type of fluid that the spiral gasket contacts.

The thickness of the filler material varies depending on conditions such as the size of the gasket, intended use, and required performance, but is usually set in the range of 0.35 to 1.0 mm.

The width of the filler material is set to be equal to or slightly larger than the width of the hoop material of the pressure receiving portion.

[Pressure-Receiving Part] The pressure-receiving part has a structure in which both sides come into contact with a sealing surface such as a pipe flange to perform a sealing function. The hoop material and the filler material are stacked and wound.

Conditions such as the material and thickness of the hoop material and filler material are set according to the intended use and required performance.

The width of the hoop material can be set in the range of 1.6 to 6.4 mm.

In addition, when the spiral gasket is manufactured, by appropriately setting the winding pressure, the deformability of the hoop material and the sealing function can be improved. Usually, the winding pressure is 0.1 ~
It can be set in the range of 0.35 MPa.

The width of the pressure receiving portion in the radial direction of the gasket
Thus, the area that performs the sealing function changes. Radial width of pressure receiving part
Is the inner diameter D of the pressure receiving part_TwoAnd outer diameter D₁And the difference. Pressure receiving part
Inner diameter D _TwoIs the piping or fluid at the gasket
Can be set according to the diameter of the passage.

At the beginning of winding on the inner periphery and the end of winding on the outer periphery of the pressure receiving portion, only the hoop material can be wound without the filler material. The number of turns of the hoop material alone may be about 1 to 3 times. The hoop members can be welded and fixed to each other at or near the inner and outer ends.

[Hoop outer ring portion] Like the outer ring in a normal spiral gasket, the hoop outer ring portion is disposed on the outer periphery of the pressure receiving portion and has a function of suppressing deformation of the pressure receiving portion to the outer peripheral side. Further, it also has a function of determining the outer peripheral position of the spiral gasket.

The hoop outer ring is formed by winding a hoop material. As a result, the hoop outer ring can exhibit appropriate rigidity and deformability.

As the hoop material, the same hoop material as the pressure receiving portion can be used, or a hoop material different from the pressure receiving portion can be used. Different hoop materials can be used in combination on the inner peripheral side and the outer peripheral side of the hoop outer ring portion.

The width of the hoop outer ring portion, that is, the width of the hoop material is set to be approximately the same as or smaller than the width of the hoop material in the pressure receiving portion. In the use state, it is preferable that both sides of the pressure receiving portion contact the sealing surface and the hoop outer ring portion does not contact the sealing surface. Specifically, the width T ₂ of the hoop material of the hoop outer ring portion
And the width T ₁ of the hoop material of the pressure receiving portion can have a relationship represented by the following equation (1).

1 ≧ T ₂ / T ₁ ≧ 0.3 (1) If the above conditions are satisfied, misalignment hardly occurs during winding in the manufacturing process, and it is possible to prevent the accompanying misalignment.

The deformation suppressing function and the deformation resistance of the hoop outer ring portion with respect to the pressure receiving portion can be appropriately set according to the winding density of the hoop material in the hoop outer ring portion. If the winding density is too high, it is difficult to exhibit the functions required for the hoop outer ring. It is preferable that the winding pressure of the hoop outer ring portion is set lower than the winding pressure of the pressure receiving portion.

As a specific condition of the winding density at which a good sealing property can be exhibited, 2.6 to 3.6 turns / m in the hoop outer ring portion.
A range of m can be employed. The winding pressure suitable for obtaining this winding density can be set in the range of 0 to 0.3 MPa. More preferably, it is 0.27 MPa or less.

The outer diameter D ₀ of the hoop outer ring portion is set in accordance with the space at the mounting location and the standard dimensions of the spiral gasket. The inner diameter D ₁ of the hoop outer ring corresponds to the outer diameter of the pressure receiving portion. Difference between the outer diameter D ₀ and the inner diameter D ₁ of the hoop outer ring portion, the radial width of the hoop outer ring portion.

The hoop material of the hoop outer ring portion can be fixed by welding at the end of winding on the outer peripheral end side. In addition, the beginning of winding on the inner peripheral end side can be fixed to the hoop material of the pressure receiving portion by welding. Further, the hoop members can be fixed to each other at appropriate intervals by welding over the entire length of the hoop member.

Specifically, every time the hoop material is wound 2 to 5 times, it can be welded to the outer periphery of the previously wound inner hoop material at 1 to 3 locations. The welding interval can be changed between the winding start side and the winding end side of the hoop material.
As the number of welding points is larger and the interval is shorter, the deformation of the hoop material is regulated, the rigidity of the outer ring portion of the hoop is increased, and the constraint on the pressure receiving portion is increased. In particular, in the case of a large diameter spiral gasket, the hoop material tends to wobble and loose,
Hoop material welding is effective. Specifically, the outer diameter 4
It is effective for spiral gaskets of about 00 mmφ.

[Swirl Gasket] With the above-described structure, other structures can be combined with the same technology as a normal spiral gasket.

The spiral gasket usually has an annular shape, but may have an elliptical shape, an elliptical shape, or a polygonal annular shape.

The dimensions, materials, operating conditions and the like of the spiral gasket are specified by industrial standards such as JIS, and can be designed according to those standards.

The sealing function of the spiral gasket is as follows: the inner pressure applied to the spiral gasket while being mounted between the sealing surfaces;
In addition, when the surface pressure applied between the sealing surface and the pressure receiving portion is specified, it can be evaluated by the amount of fluid leaking from the inner peripheral side to the outer peripheral side of the spiral gasket or vice versa.

The spiral gasket of the present invention can achieve a very small amount of leakage in a wide range from the low to high surface pressure and internal pressure.

For example, a non-asbestos inorganic material is used for the filler material.
When used with a tightening surface pressure of 20 to 30 MPa,
For an internal pressure of ~ 1MPa, the leakage amount is 1.0 × 10^-FourPa
・ M ^Three/ S or less, used at a tightening surface pressure of 40 to 50 MPa
Sometimes, for an internal pressure of 0 to 5 MPa, the leakage amount 2.0 ×
10^-FivePa ・ m^Three/ S or less, tightening surface pressure 60 to 70 MPa
When used at an internal pressure of 0 to 12MPa,
2.0 × 10^-FivePa ・ m^Three/ S performance is achieved
Wear.

When the expanded graphite material is used as the filler material, when the expanded surface material is used at a tightening surface pressure of 20 to 30 MPa, the expanded material is 0 to 30 MPa.
For an internal pressure of 2 MPa, the leakage amount is 1.0 × 10 ⁻⁶ Pa ·
m ³ / s or less, when used at a tightening surface pressure of 40 to 50 MPa, a leakage amount of 9.0 × 1 with respect to an internal pressure of 0 to 5 MPa.
0 ^-7 Pa · m ³ / s or less, when used in tightening surface pressure 60～70MPa, against the internal pressure of 0～12MPa, leak rate 9.0 × following 10 ^-7 Pa · m ³ / s Performance can be achieved.

Here, the measuring device and measuring method described later can be applied to the measurement of the amount of leakage, but the measuring device and the measuring conditions can be changed as long as similar measurement results are obtained.

By appropriately setting the amount of strain in the axial direction in the use state of the spiral gasket, good sealing performance can be exhibited. Specifically, gasket surface pressure 1
It is preferable that the amount of strain at 0 to 70 MPa is 140 to 200% as compared with a conventional spiral gasket having a block-shaped outer ring. In order to set such a distortion amount, it is effective to adjust the winding density of the hoop material described above.

When the non-asbestos inorganic material is used as the filler material, the specific strain value is 4% or more when used at a tightening surface pressure of 20 MPa and when the tightening surface pressure is 70 MPa. Preferably, the strain amount is 25% or less.
When expanded graphite material is used for filler material, tightening surface pressure 2
When used at 0 MPa, the strain amount is 5% or more and the tightening surface pressure is 7
When used at 0 MPa, the strain amount is preferably 30% or less.

[Application] The spiral gasket can be used in various applications where a spiral gasket has been used.

It is used for flanges of various pipes, joint surfaces of fluid passage portions of various devices, lids and openings of fluid containers, valves and the like.

The usage of the gasket may be classified into a high pressure application, a low pressure application, and the like depending on the internal pressure. The spiral gasket of the present invention can correspond to a wide range from a low pressure to a high pressure. Specifically, good performance can be exhibited in the set ranges of the internal pressure and the surface pressure described above.

[0053]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS [Swirl Gasket] The spiral gasket G shown in FIGS. 1 and 2 has a hollow annular shape as a whole, and has a pressure receiving portion 10 on the inner peripheral side and a hoop outer ring portion 20 on the outer peripheral side. ing.

In the pressure receiving section 10, a hoop material 14 made of a thin metal band material such as stainless steel and a filler material 12 made of non-asbestos paper or the like are overlapped and spirally wound. The hoop member 14 is formed in a V-shape having a flat cross section. The material of the filler material 12 is a flat tape shape, but by being superposed on the hoop material 14,
A similar V-shape is formed along the cross-sectional shape of the hoop material 14.

At the innermost circumference and the outermost circumference of the pressure receiving portion 10, only the hoop material 14 is wound once or a small number of times. The inner peripheral end of the hoop member 14 is fixed by welding. The welding position may be only one position, or may be set at a plurality of positions with an interval. Hoop material 1
The outer peripheral end of 4 is fixed by welding in the same manner as the inner peripheral end. However, even if the outer peripheral end of the hoop material 14 is not fixed,
In some cases, the hoop outer ring portion 20 can prevent the hoop material 14 from being unraveled.

The hoop outer ring 20 is formed by spirally winding a hoop 22 made of the same thin metal band as the hoop 14 of the pressure receiving unit 10. The hoop material 22 of the hoop outer ring portion 20 has a V-shaped cross section that is bent at substantially the same angle as the hoop material 14 of the pressure receiving portion 10. However, the width T ₂ of the hoop material 22 of the hoop outer ring portion 20 is different from the pressure receiving portion 10.
Is slightly smaller than the width T ₁ of the hoop material 14.

The V-shaped concave shape of the inner peripheral end surface of the hoop outer ring portion 20 fits into the V-shaped projecting shape of the outer peripheral end surface of the pressure receiving portion 10. Therefore, the pressure receiving portion 10 and the hoop outer ring In a state where the part 20 is assembled, the gasket G is prevented from moving or shifting in the axial direction.

The inner peripheral end of the hoop member 22 of the hoop outer ring portion 20 is fixed to the outer peripheral end or outer peripheral surface of the pressure receiving portion 10 by welding. The outer peripheral end of the hoop material 22 of the hoop outer ring portion 20 can be fixed by welding similarly to the inner and outer peripheral ends of the pressure receiving portion 10.

By setting the outer diameter D _{0 of} the hoop outer ring portion 20, the inner diameter D ₁ of the hoop outer ring portion 20 (that is, the outer diameter of the pressure receiving portion 10), and the inner diameter D ₂ of the pressure receiving portion 10, the size of the spiral gasket G is reduced. Decided.

[Another Embodiment] The spiral gasket G shown in FIG. 3 basically has the same structure as that of the above-mentioned embodiment, but the structure of the hoop outer ring portion 20 is slightly different.

The width T ₂ of the hoop material 22 of the hoop outer ring portion 20
Is set to be the same as the width T ₁ of the hoop member 14 of the pressure receiving portion 10.

When the spiral gasket G is manufactured, the filler member 12 and the hoop material 14 are stacked and wound in the pressure receiving portion 10, and then the hoop outer ring portion 20 is formed by further winding only the hoop material 14. . Therefore, the hoop material 14 of the pressure receiving portion 10 and the hoop material 22 of the hoop outer ring portion 20 are
It is composed of the same sheet metal strip continuously wound,
The joining by welding at the boundary between the pressure receiving portion 10 and the hoop outer ring portion 20 becomes unnecessary.

In the structure of the above-described embodiment, a gap is unlikely to be formed between the both side surfaces of the hoop outer ring portion 20 of the spiral gasket G and the sealing surfaces arranged on both sides in the used state. As a result, even when used in the state of being exposed outdoors, or when used in the sea or other environments where water gets wet, rainwater or seawater infiltrates, and the material of the pressure receiving portion 10 is corroded or damaged. Can be prevented.

[Sealing Action of Spiral Gasket] FIG.
Sealing action in use of a spiral gasket G employing the hoop outer ring portion 20 made of the hoop material 22 of the present invention and a spiral gasket G 'employing a block annular outer ring 29 and inner ring 40 made of conventional steel or the like. The difference is schematically explained.

<Conventional Structure> In the conventional structure shown in FIG. 4 (a), a spiral gasket G 'is mounted between the sealing surfaces 30, such as pipe flanges, and when a tightening pressure is applied from both sides, the sealing surface The filler material 12 and the hoop material 14 of the pressure receiving portion 10 abutting on 30, 30 are compressed in the thickness direction.

The pressure receiving portion 10 tends to deform to the outer diameter side.
However, since the outer ring 29 is a rigid body made of a steel block or the like, deformation of the outer diameter portion of the pressure receiving portion 10 to the outer diameter side is suppressed by the outer ring 29. Thereby, it is considered that the contact stress of the sealing surfaces 30, 30 is increased and the sealing is achieved without the escape of the tightening pressure. Therefore, in general, the outer ring 29 is made of a metal having high rigidity and the tightening pressure is increased to improve the sealing performance.

However, no matter how much the tightening force is increased, there is a limit that the sealing performance is not further improved. The cause of such a limitation is considered as follows.

The outer ring 29 has too high rigidity, and
Is strongly suppressed by the outer ring 29, the angle of the V-shape of the hoop material 14 and the filler material 12 constituting the pressure receiving portion 10 cannot be reduced to a certain value or more. Since the stress at the contact portion between the material 14 and the filler material 12 does not increase, the sealing performance at the contact surface between the hoop material 14 and the filler material 12 inside the gasket is
It is considered that the reason is that it does not improve beyond a certain limit.
That is, leakage (also referred to as internal permeation leakage) passing between the hoop material 14 and the filler material 12 occurs.

The above problem becomes more pronounced as the tightening pressure is lower. Therefore, especially in the case of use conditions where the tightening pressure is low, the sealing performance is particularly low. This is the reason why a sufficient sealing function cannot be achieved in the low pressure class in which the tightening surface pressure is low as described in the section of the problem.

Further, in the case of the spiral gasket G 'having the block-shaped outer ring, since the pressure receiving portion 10 is hardly deformed toward the outer diameter side due to the presence of the outer ring 29 having high rigidity, the gasket G' is compressed during use. The generated radial stress acts strongly in the radial direction, and tends to induce buckling, that is, chrysanthemum-shaped deformation at the inner peripheral end. To prevent this chrysanthemum-shaped deformation, the inner ring 40 was required. That is,
The chrysanthemum-shaped deformation is prevented by supporting the pressure receiving portion 10 from the inner diameter side with the inner ring 40.

<Structure of the Present Invention> As shown in FIG.
The hoop outer ring portion 20 of the present invention is configured by winding a hoop material 22.

Also in the case of the present invention, the pressure receiving portion 10 to which the tightening force is applied tends to deform to the outer diameter side. At this time, the hoop outer ring portion 20 moves the hoop material 2 in response to the deformation of the pressure receiving portion 10.
2 can be deformed. As a result, the deformation of the pressure receiving portion 10 toward the outer diameter side is not strongly suppressed unlike the conventional structure. In the pressure receiving portion 10, the contact stress between the hoop material 14 and the filler material 12 increases, and the sealing property between the hoop material 14 and the filler material 12 inside the pressure receiving portion 10 is extremely well achieved. .

The hoop outer ring portion 20 does not restrict the pressure receiving portion 10 at all, but exerts an appropriate restricting force. For example, in FIG. 4A, in a structure without the outer ring 29, that is, in a basic spiral gasket without the outer ring, the tightening pressure almost escapes. However, if the hoop outer ring portion 20 exerts an appropriate restraining force on the pressure receiving portion 10, the pressure receiving portion 1
At 0, both sides of the filler material 12 are brought into contact with the sealing surfaces 30, 30 with sufficient strength, and a good sealing function can be exhibited.

As described above, in the structure of the present invention, the sealing performance at the contact surface between the filler material 12 and the hoop material 14 is improved. As a result, for example, in the conventional structure, the leakage amount is 2 to
Even when the limit is about 5 × 10 ⁻⁵ Pa · m ³ / s, the leakage amount 2 × 1 can be obtained by adopting the structure of the present invention.
High sealing performance of less than 0 ^-5 Pa · m ³ / s can be achieved.

In the structure of the present invention, the hoop material 14 of the pressure receiving portion 10 can be sufficiently deformed even when the tightening force is low, so that a good sealing function can be achieved even when used under low pressure conditions. .

Further, the provision of the hoop outer ring portion 20 has an advantage that the inner ring can be omitted. In the present invention, since the deformation of the pressure receiving portion 10 to the outer diameter side is allowed to a certain extent, the stress in the inner diameter direction is reduced, and the chrysanthemum-shaped deformation at the inner peripheral end hardly occurs. Therefore, it is not necessary to provide an inner ring for preventing chrysanthemum deformation.

However, for the purpose of preventing the internal fluid from directly contacting the pressure receiving portion 10, an inner ring of a block structure is provided on the inner diameter side of the pressure receiving portion, or an empty portion of a hoop material is provided. It is effective to put it.

[0078]

Embodiment 1 Embodiment 1 has a basic structure shown in FIG.
IS standard [with outer ring JIS10K nominal size 80A
(ID98, OD118, outer ring OD134, t4.
5) The spiral gasket corresponding to [5] was manufactured.

The hoop material 14 of the pressure receiving section 10 has a thickness of 0.2
A V-shaped strip made of SUS304 having a width of 4.5 mm and a width of 4.5 mm was used. After the hoop material 14 is empty winding twice, the filler material 12 made of non-asbestos inorganic paper width 4.5 mm (Oribesuto Co.) by overlapping the hoop material 14, the inner diameter D ₂ = 98 mm, an outer diameter D ₁ = 118 mm. The winding pressure was set to 0.27 MPa. At the end of the winding, only the hoop material 14 was wound twice and then fixed by welding at one point to produce the pressure receiving portion 10.

SUS3 having a thickness of 0.2 mm and a width of 3.2 mm
The hoop material 22 formed in a V-shape similar to the hoop material 14 of the pressure-receiving part 10 was overlapped on the strip made of 04, and the hoop material 22 was welded to the hoop material 14. The hoop material 22 is set to the outer ring outer diameter dimension D ₀ = 13.
It was wound at a winding pressure of 0.1 MPa until it became 4 mm. The end of the winding was fixed by welding at three points with a gap of 2 mm in the circumferential direction. The total number of turns of the hoop outer ring portion 20 thus manufactured was about 21 times.

[Embodiment 2] It has the basic structure shown in FIG.
JIS standard [JIS 10K with outer ring nominal size 100
A (ID123, OD143, outer ring OD159, t
4.5)), and a spiral gasket corresponding to the above was manufactured.

The hoop material 14 of the pressure receiving section 10 has a thickness of 0.2
A V-shaped strip made of SUS304 having a width of 4.5 mm and a width of 4.5 mm was used.

After the hoop material 14 is wound twice, the width is 4.5.
A filler material 12 made of non-asbestos inorganic paper (manufactured by Olivet Co., Ltd.) having a diameter of ₂ mm
= 98 mm and an outer diameter D ₁ = 118 mm.
The winding pressure was set to 0.27 MPa. At the end of winding, only the hoop material 14 was wound twice twice to produce the pressure receiving portion 10.

Subsequently, the hoop material 14 used for the pressure receiving portion 10 is continuously wound around the outer periphery of the pressure receiving portion 10 as it is,
It was used for the hoop material 22 constituting the hoop outer ring portion 20. In the hoop outer ring portion 20, the hoop material 22 was wound at a winding pressure of 0.1 MPa until the outer ring outer diameter D ₀ = 159 mm. The end of the winding was fixed by welding at three points with a gap of 2 mm in the circumferential direction. The total number of turns of the hoop outer ring portion 20 thus manufactured was about 25 times.

Comparative Example 1 A spiral gasket corresponding to JIS standard having a conventional structure was prepared corresponding to Example 1. It has a structure corresponding to FIG. Mild steel (SP
The structure and overall dimensions of the pressure receiving portion are the same as those in the first embodiment except that a block annular outer ring made of CC) is used.

Comparative Example 2 A spiral gasket of a basic type without an outer ring was prepared corresponding to Example 1. It has the same material and structure as the first embodiment except that it has no hoop outer ring portion.

[Performance Comparison Test] The sealing performance of Examples 1 and 2 and Comparative Examples 1 and 2 was measured, and the results were evaluated.

<Test Apparatus> The test apparatus shown in FIG. 5 is used.

Between the upper and lower flange plates 110 and 120,
The gasket G to be tested is sandwiched and mounted. The flange plate 120 is provided with the hydraulic load applying device 1
Pressed downward by 40. An overhanging portion 122 is provided at the upper end of the flange disk 120. The amount of movement of the flange disc 120 can be measured by the dial gauge 150 abutting on the overhang portion 122. The amount of movement of the flange disc 120 indicates the amount of distortion of the gasket G.

A gas supply passage 174 is opened in the center of the lower flange plate 110, and nitrogen gas is supplied to the gas supply passage 174 from a nitrogen gas cylinder 170 under pressure. The supply pressure of nitrogen gas is indicated by a pressure gauge. The internal pressure applied to the gasket G changes by adjusting the pressure of the nitrogen gas.

The outer periphery of the opposed portion of the flange disks 110 and 120 is covered by a flange cover 130 via an O-ring 20. The pressure in the inner space of the flange cover 130 is introduced into the burette 160 set up in the liquid tank 164 via the rubber tube 162, and is indicated as the liquid level. When the internal pressure of the nitrogen gas applied to the gasket G leaks from the gasket G to the outside, the liquid level of the burette 160 changes.

<Test Method> Flange disk 11 of test equipment
The gasket G is mounted between 0 and 120.

A load corresponding to a predetermined gasket stress is applied by the hydraulic load application device 140. When the predetermined load is reached, the amount of strain at that time is held, and left for 10 minutes to reduce the stress relaxation.

The internal pressure of the nitrogen gas is applied and the liquid level of the burette 160 is measured. The amount of leakage is calculated from the amount of decrease in liquid level per unit time. The measurement was based on 5 minutes. When the amount of leakage is very small, the amount of leakage gas is set to 0.
The amount of leakage was calculated by measuring the time required to reach 2 ml.

<Test Results> The graph shown in FIG. 6 shows how the strain and gasket stress change over time during the test. The following table shows the measurement results of the amount of leakage. In the table,
In the pressure class, the pressure (internal pressure) of the sealing environment is divided into three stages, and the tightening surface pressure of the gasket required to exhibit the sealing function in each environment is set.

[0096]

[Table 1] <Results of sealing test> ────────────────────────────────── Specifications Leakage Pa ・m ³ / s Winding pressure MPa Pressure class (surface pressure / internal pressure MPa) Pressure receiving part / outer ring part Low pressure (20 / 0.5) Medium pressure (50/5) High pressure (70/12) ────────── ──────────────────────── Example 1 0.27 / 0.15 (hoop) 5 × 10 ^-5 <1.7 × 10 ^-5 <1.7 × 10 ^-5 Example 2 0.27 / 0.27 (hoop) 8 × 10 ^-5 <1.7 × 10 ^-5 <1.7 × 10 ^-5 Comparative Example 1 0.27 / − (block) 5 × 10 ^-4 3 × 10 ^-4 2 × 10 ^-4 Comparative Example 2 0.15 / − (none)> 2 × 10 ^-2 > 2 × 10 ^-2 1 × 10 ^-3 ────────────────────────検 出 Detection limit: 1.7 × 10 ⁻⁵ Pa · m ³ / s <Evaluation> (1) From the results in the above table, an example having a hoop outer ring made of hoop material 1 and 2 are block hoops As compared with Comparative Example 2 Comparative Example 1 and without outer ring having a ring portion,
In any of the low, medium and high pressure classes, the amount of leakage was proved to be extremely small. Specifically, the amount of leakage has been reduced to about 1/10. Especially in the low pressure class,
In Comparative Examples 1 and 2, practically sufficient sealing performance cannot be exhibited, but in Examples 1 and 2, a favorable sealing function can be exhibited.

(2) According to the compression and decompression diagram of FIG. 6, it can be seen that Examples 1 and 2 are more easily deformed than Comparative Example 1 in all pressure classes.

From the results shown in FIG. 6 and the above table, the internal pressure was 0.5MPa.
a) In the low pressure class, the gasket tightening surface pressure is 20M
Even at a low tightening pressure of Pa, which is allowable in this class, a strain of about 10% is generated, which indicates that a good sealing function is exhibited.

Similarly, in the medium pressure class with an internal pressure of 5 MPa, the strain is reduced to about 20% by tightening with a surface pressure of 50 MPa, and in the high pressure class with an internal pressure of 12 MPa, the strain is reduced to about 25%. Thus, a good sealing function is exhibited.

From these results, in the embodiment of the present invention,
By employing the hoop outer ring portion, the restraining force on the pressure receiving portion can be applied within an appropriate range that is not too strong, and the contact stress between the hoop material and the filler material in the pressure receiving portion is increased. It can be considered that the high density state prevented the internal permeation leakage, prevented the escape of the tightening pressure, and improved the sealing function by effectively applying the tightening pressure.

(3) The spiral gaskets of Examples 1 and 2 are as follows:
CAAA (US Clean Air Act Amendmen
t of 1990), which is the atmospheric concentration of 100 ppm
Leakage 5 × 1 equivalent to (California regulation value)
The standard of 0 ^-5 Pa · m ³ / s can be satisfied.

[0102] In particular, low-pressure class (internal pressure 0.5MPa or less, tightening pressure 20 MPa) in the leakage amount of Examples 1 and 2, 1 × 10 achieved in conventional joint sheet (paste application state) ^{- It} can be reduced to about 1/2 compared to ⁴ Pa · m ³ / s. Therefore, it was demonstrated that the low pressure class can be effectively used as a non-asbestos seal member replacing the conventional joint sheet.

(4) In Examples 1 and 2, handling operations such as mounting to a test apparatus and positioning were performed as well as Comparative Example 1 with an outer ring.

(5) In the manufacturing process, in Examples 1 and 2, the filler material 12 and the hoop material 1 serving as the pressure receiving portion 10 were used.
Subsequent to the winding operation of No. 4, the hoop material 22 serving as the hoop outer ring portion 20 could be wound, and a series of manufacturing operations could efficiently manufacture. In particular, in Example 2, the same hoop members 14 and 22 were continuously wound around the pressure receiving portion 10 and the hoop outer ring portion 20 as they were, so that the manufacturing operation could be performed extremely efficiently. On the other hand, in Comparative Example 1, a manufacturing process of the block-shaped hoop outer ring portion, a winding process of the pressure receiving portion, and a joining process of the pressure receiving portion and the hoop outer ring portion were required.

According to the present invention, it has been demonstrated that the number of manufacturing steps can be reduced and the manufacturing cost of the hoop outer ring portion can be reduced, which can greatly contribute to the improvement of the manufacturing efficiency and the cost reduction of the spiral gasket.

[Change of Filler Material] The same test as described above was performed by changing the material of the filler material 12 used in the pressure receiving portion 10.

In Example 1, the filler material 12 made of non-asbestos paper was replaced with expanded graphite (Example 1).
a) was prepared. In Comparative Example 1, the filler material 1
2 was replaced with expanded graphite (Comparative Example 1a).

Each sample was subjected to the same sealing test as described above, and the results are shown in the compression reconstruction diagram of FIG. 7 and the results of measurement of the leakage amount in the table below.

[0109]

[Table 2] <Sealing test result (expanded graphite)> ──────────────────────────────── Specifications Leakage Pa · m ³ / s Pressure class (surface pressure / internal pressure MPa) Filler material Low pressure (20/2) Medium pressure (50/4) High pressure (70/10) ────────────── ────────────────── Example 1a Expanded graphite 1.0 × 10 ^-6 <8.7 × 10 ^-7 <8.7 × 10 ^-7 Comparative Example 1a Expanded graphite 1.0 × 10 ^-5 9.0 × 10 ^-5 8.0 × 10 ^-5限界 Detection limit: 8.7 × 10 ^-7 Pa · m ³ / s <Evaluation> (1) Even if the filler material is changed from non-asbestos paper to expanded graphite, it is demonstrated that the present invention can exhibit a much better sealing function than the conventional structure. Was done.

[Turn Number Comparison Test] The relationship between the number of turns of the hoop material 22 in the hoop outer ring 20 and the sealing performance was measured and evaluated.

In Example 1, a plurality of samples having different numbers of turns of the hoop material 22 were prepared and subjected to the same sealing test as described above. The following table shows the results.

[0112]

[Table 3] <Results of winding number evaluation test> ─────────────────────────── Specifications Leakage amount Pa ・ m ³ / s Hoop outer ring Pressure class (surface pressure / internal pressure MPa) Number of turns Low pressure (20 / 0.5) Medium pressure (50/5) ────────────────────────── ─ example ^{11 10 1.0 × 10 -4 1.0 ×} 10 -5 example ^{12 8 3.5 × 10 -4 1.0 ×} 10 -4 example ^{13 4 5.0 × 10 -4 3.0 ×} 10 -4 ─────── ──────────────────── <Evaluation> (1) As the number of turns of the hoop material 22 of the hoop outer ring portion 20 increases, the amount of leakage decreases, and the sealing performance is improved. It has been proven to increase. It can be seen that if the number of turns is 10, the extremely high sealing performance can be exhibited even in the low pressure class.

(2) When the number of windings is small as in the thirteenth embodiment, the leakage amount is almost the same as that in the case of using the block-shaped outer ring of the comparative example 1, but the material cost and the manufacturing process are simplified. In terms of realization, the hoop outer ring is more advantageous.

[0114]

The spiral gasket of the present invention has a hoop outer ring portion having a structure in which a hoop material is wound around the outer periphery of the pressure receiving portion. Deforms moderately and performs appropriate restraint on the pressure receiving portion. As a result, in the pressure receiving portion, a sufficiently large surface pressure acts between the filler material and the hoop material, the internal leakage between the hoop material and the filler material is improved, and the sealing performance is improved.

As a result, good sealing performance can be exhibited under any of a wide range of operating conditions from high pressure to low pressure, and the gasket performance of the spiral gasket can be remarkably improved.

[0116] The spiral gasket can be satisfactorily applied to use conditions and applications that have been difficult to use with a conventional spiral gasket, and can greatly contribute to the expansion of the application range or application of the spiral gasket. .

In a conventional spiral gasket using a hoop outer ring portion having a block structure, it is necessary to manufacture and prepare hoop outer ring portions having different dimensions and shapes for each standard dimension. By simply changing the number of turns, spiral gaskets having different outer diameters can be easily manufactured. Further, non-standard products out of the standard dimensions can be easily dealt with.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a spiral gasket showing an embodiment of the present invention.

FIG. 2 is a plan view

FIG. 3 is a cross-sectional view illustrating another embodiment.

FIG. 4 is a schematic view for explaining the sealing action of the spiral gasket.

FIG. 5 is a structural diagram of a performance test apparatus.

FIG. 6 is a diagram showing performance test results;

FIG. 7 is a diagram showing performance test results when filler materials are changed.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Pressure receiving part 12 Filler material 14 Hoop material 20 Hoop outer ring part 22 Hoop material 30 Sealing surface G Spiral gasket

Claims (10)

[Claims] 1. A spiral gasket which is annular and is mounted between opposing sealing surfaces to perform a sealing function, wherein a hoop material and a filler material are wound in an overlapping manner, and both side surfaces are the sealing surfaces. A spiral gasket comprising: a pressure receiving portion that is in contact with the pressure receiving portion; and a hoop outer ring portion that is disposed around the pressure receiving portion and has a hoop material wound thereon. 2. The spiral gasket according to claim 1, wherein the hoop material of the outer hoop portion is made of the same material as the hoop material of the pressure receiving portion. 3. The hoop material of the outer hoop portion of the hoop is made of the same hoop material continuous with the hoop material of the pressure receiving portion.
Spiral gasket described in 1. 4. according to any one of claims 1 to 3, the width T ₁ of the hoop material of the pressure receiving portion and the width T ₂ of the hoop material of the hoop outer ring portion has a relationship shown in following formula (1) Spiral gasket. 1 ≧ T ₂ / T ₁ ≧ 0.3 (1) 5. The spiral gasket according to claim 1, wherein the number of turns of the hoop material in the hoop outer ring portion is 10 or more. 6. The hoop material of claim 1, wherein the hoop material of the hoop outer ring portion is welded to the outer periphery of the hoop material wound first at one to three locations every two to five turns. The spiral gasket described. 7. When the filler material is made of a non-asbestos inorganic material, the filler material is used by being mounted between the sealing surfaces, and when used at a tightening surface pressure of 20 to 30 MPa between the sealing surface and the pressure receiving portion, The leakage amount is 1.0 × 10 ⁻⁴ Pa · m ³ / s or less with respect to the internal pressure of １1 MPa, and when used at a tightening surface pressure between the sealing surface and the pressure receiving portion of 40 to 50 MPa, the leakage amount is 0 × 10 ⁻⁴ Pa · m ³ / s. The leakage amount is 2.0 × 10 ⁻⁵ Pa · m ³ / s or less with respect to the internal pressure of ５5 MPa, and when used at a tightening surface pressure of 60 to 70 MPa between the sealing surface and the pressure receiving portion, the leakage amount is zero. The leakage amount is 2.0 × 10 ⁻⁵ Pa · m ³ / s or less for an internal pressure of 12 to 12 MPa.
The spiral gasket according to any one of the above. 8. The filler material is made of an expanded graphite material, is used by being mounted between the sealing surfaces, and when used with a tightening surface pressure between the sealing surface and the pressure receiving portion of 20 to 30 MPa, the filler material has an The leakage amount is 1.0 × 10 ⁻⁶ Pa · m ³ / s or less with respect to the internal pressure of 2 MPa. When the internal pressure is 5 MPa, the leakage amount is 9.0 × 10 ⁻⁷ Pa · m ³ / s or less. The leakage amount is 9.0 × 10 ⁻⁷ Pa · m ³ / s or less at an internal pressure of 12 MPa.
The spiral gasket according to any one of the above. 9. The filler material is made of a non-asbestos inorganic material, and is used by being mounted between the sealing surfaces. The spiral gasket according to any one of claims 1 to 6, wherein the strain amount is 25% or less when used at a tightening surface pressure of 70 MPa between the sealing surface and the pressure receiving portion. 10. The method according to claim 1, wherein the filler material is made of an expanded graphite material, and is used while being mounted between the sealing surfaces. The spiral gasket according to any one of claims 1 to 6, having a strain amount of 30% or less when used at a tightening surface pressure of 70 MPa between the sealing surface and the pressure receiving portion.