JP4248049B2 - Seal member and connection structure - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a seal member and a connection structure.
[0002]
[Prior art]
Conventionally, ring-shaped solid Teflon sealing members having excellent chemical resistance have been used for connecting portions of piping in chemical and food production lines. However, this seal member has a sag over time, and if this sag is left as it is, leakage may occur from the connection portion, so it has to be replaced periodically.
[0003]
Therefore, in order to improve this sag phenomenon, a sealing member having a structure in which an asbestos sheet having the same shape as the above-mentioned Teflon sealing member is used as a core and the outside of the core is covered with a Teflon sheet is used. It was. Thereafter, asbestos treatment sometimes became a problem at the stage of disposal of the sealing member having such a configuration, so non-asbestos was used as an alternative to asbestos.
[0004]
FIG. 7 is a cross-sectional view of a sealing member whose core is covered with a Teflon sheet. As shown in the figure, the non-asbestos core 1101 is a ring-shaped plate member having a hole 1102 formed in the center. The Teflon sheet 1103 is a ring-shaped solid sheet material that is processed to cover both surfaces of the core part 1101. Further, this Teflon sheet 1103 is made of a solid sheet material having a predetermined thickness, which is half the thickness, parallel to both planes of the sheet material from the outer peripheral surface toward the central hole and before the inner peripheral surface 1104. A cut is made. By this processing, the sheet material 1103 is divided into two sheet portions 1103a and 1103b except for the vicinity of the inner peripheral surface. These sheet portions 1103a and 1103b are processed so as to cover both surfaces of the core portion 1101.
[0005]
However, the Teflon sheet 1103 processed in this way has a problem that it tends to be stretched and deformed under a high temperature and high pressure environment.
[0006]
That is, since the inner peripheral surface 1104 of the Teflon sheet is deformed by being pushed outward by the internal pressure of the pipe in a high temperature state, the inner peripheral surface of the core portion 1101 is pushed outward. Since the frictional force generated between the sheet portions 1103a and 1103b of the Teflon sheet and the core portion 1101 is extremely small, the inner peripheral surface of the core portion 1101 is gradually spread by the pressure from the inside toward the outside. In the end, the core part 1101 is damaged. Therefore, it was considered that the core was reinforced with a metal mesh, but the heat resistance improved somewhat as the strength of the core increased, but damage under high pressure conditions could be fundamentally avoided. There wasn't.
[0007]
FIG. 8 is a characteristic diagram showing the relationship between pressure resistance and heat resistance of these conventional sealing members. In the figure, the horizontal axis indicates temperature (° C.) and the vertical axis indicates the pressure (Kg / cm ² ) inside the pipe. In the figure, a line denoted by reference numeral 2101 represents a characteristic of only non-asbestos, and a line denoted by reference numeral 2102 represents the characteristic of a seal member in which non-asbestos is covered with a Teflon sheet. Heat resistance of 100 ° C or higher is required for use in steam pipes, etc., but it is a material that does not contain asbestos, has chemical resistance, and has little sag over time, heat resistance and pressure resistance As described above, a sealing member that is excellent and has insulating properties has not been developed so far.
[0008]
In view of this, a sheet-like sealing member has been developed in which a large number of thin-film sheets made of polytetrafluoroethylene (hereinafter referred to as PTFE) resin are laminated and molded to a predetermined thickness.
[0009]
This seal member has chemical resistance, has little sag over time, and has excellent heat resistance as compared with a solid Teflon sheet, and therefore, a core portion such as non-asbestos is also unnecessary. In addition, unlike a conventional solid Teflon sheet, it has a characteristic of being soft and is commonly called a soft PTFE sheet.
[0010]
However, in the case of such a soft PTFE sheet, the characteristic that the sealing member itself is soft and the degree of tightening that is conventionally performed at the stage of incorporation into the pipe do not mesh well, and the liquid or gas in the pipe does not fit well. Sometimes leaked outside. The degree of tightening that is conventionally performed is that when the sealing material is hard, the degree of tightening is tight, and when it is soft, the degree of tightening is slightly loosened. Therefore, even in the case of this soft PTFE sheet, in order to make it possible for the worker who performs the construction to tighten it tightly, it is not as hard as the conventional solid Teflon sheet, but it is a manufacturing device so that it becomes a slightly harder seal member. It has been made. This eliminated liquid leakage from the pipe connection.
[0011]
By the way, compared with the conventional sealing member for pipe connection described above, a larger size, for example, one having an outer diameter of 1 m or more is used in a different scene from the above. However, the following configuration was common.
[0012]
That is, when the seal member is assembled between the flange portions of the pipe, a hard portion serving as a core is necessary to prevent deformation due to its own weight. In that regard, the conventional configuration described in FIG. 7 has been applied to a large-sized seal member.
[0013]
In this case, hard core non-asbestos or the like was used as the core part 1101. Further, the sheet portions 1103a and 1103b of the Teflon sheets as the covering portions are solid but have a characteristic that they are softer than the non-asbestos core portion 1101. As described above, the structure including the hard core portion and the softer covering portion enables the reaction force against the tightening force necessary for the sealing material to act more effectively on the hard core portion, and the surface of the Teflon sheet is more effective. Also, the shape of the fine irregularities caused by scratches on the surface of the flange portion has a characteristic that it is comparatively easy to blend.
[0014]
[Problems to be solved by the invention]
However, even if the soft PTFE sheet hardened as described above is used and the degree of tightening is appropriate, a phenomenon of gas leakage occurs, and it cannot be used as a sealing member for a connection part of a pipe that handles high-pressure gas. There was a problem.
[0015]
Therefore, the inventor of the present application examined in detail the leakage phenomenon of high-pressure gas and elucidated the cause.
[0016]
That is, as described above, the above-described soft PTFE sheet is formed by laminating a number of thin film sheets made of PTFE resin. It has been found that the gas leakage is caused by this laminated structure, and the high-pressure gas leaks outside through the layers.
[0017]
On the other hand, in the conventional configuration of the large-sized seal member described above, the Teflon sheet itself is solid, so that it has a certain degree of hardness, and the seal member as a whole is not easily deformed. For this reason, waviness with a large pitch (or deformation such as undulation) that occurs in the flange portion cannot be absorbed by a slight deformation amount by the seal member itself, and a gap is formed between the flange surface and there. There was a disadvantage that leakage occurred. In order to prevent such a leak, it is necessary to insert a shim that fills the gap, and there is a drawback that it takes time and effort during the mounting operation.
[0018]
An object of the present invention is to provide a sealing member and a connection structure that can prevent gas leakage in consideration of the above-described problems of the conventional sealing member.
[0019]
Another object of the present invention is to provide a seal member that can absorb the waviness of the flange surface while having conformability to the flange surface.
[0020]
[Means for Solving the Problems]
The first aspect of the present invention (corresponding to the invention of claim 1) is a sealing member for preventing gas leakage of a plate-like body formed by laminating thin film sheets containing polytetrafluoroethylene resin as a material. Because
The plate-like body is a ring-like plate-like body,
The thickness of at least the outer peripheral portion of the ring-shaped plate-like body is thinner than other portions to the extent that the gas does not leak due to pressurization in the stacking direction of the stack, and is in contact with the plate-like body. The sealing member is characterized in that it is set to an extent that it is thinner than the maximum thickness after tightening of the other portions after the side flange portions are properly tightened .
[0022]
An eighth aspect of the present invention (corresponding to the invention described in claim 8 ) is a first flange portion formed in the opening of the tubular body,
A second flange portion that fits into the first flange portion;
Said first flange portion, is sandwiched between the second flange portion, and a carboxy seal member order to prevent leakage of gas in the interior of the tubular body,
The flange portion in contact with the seal member is a connection structure that does not have an uneven shape that fits with the uneven shape formed by the thick and thin portions of the seal member.
[0023]
Further, the ninth aspect of the present invention (corresponding to the invention of claim 9 ) is a core part which is a ring-shaped plate,
It is formed by laminating a thin film-like sheet containing polytetrafluoroethylene resin as a material, and includes a seal part softer than the core part,
The seal part is folded back from one surface to the other surface along the inner peripheral edge of the core so as to be along both surfaces of the core.
The sealing member is characterized in that the outer diameter is 500 mm or more .
[0024]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below with reference to the drawings.
(Embodiment 1)
Fig.1 (a) is sectional drawing which shows schematic structure of the connection structure of piping in one embodiment of the connection structure of this invention. Moreover, FIG.1 (b) is sectional drawing which shows the connection state of piping.
[0025]
Fig.2 (a) is a top view of the sealing member in this Embodiment, FIG.2 (b) is AA 'sectional drawing of a sealing member.
[0026]
The configuration of the present embodiment will be described with reference to these drawings.
[0027]
As shown in FIG. 1A, the first flange portion 103 is a flange for pipe connection provided around the opening 102 of one pipe 101. The second flange portion 106 is a flange for pipe connection provided around the opening 104 of the other pipe 105. Both pipes 101 and 105 have the same inner diameter. Moreover, the shape and size of both flange parts 103 and 106 are the same, and the surface inside these flange parts 103 and 106 is a plane. The seal member 110 is a pipe connection gasket disposed between the flange portions 103 and 106. The seal member 110 is a ring-shaped plate.
[0028]
In the present embodiment, as the material of the seal member 110, a sheet-like seal member (specifically, Japan Gore-Tex Corporation) is formed by laminating a number of thin film sheets made of PTFE resin and molding them to a predetermined thickness. Company Gore-Tex Hyper Sheet Gasket) is used. As described above, this sheet material is excellent in heat resistance and insulation resistance, is harmless, and has a characteristic of being soft unlike a conventional solid Teflon sheet. The sealing member 110 is used by processing this soft sheet material. The processing method will be further described later with reference to FIGS. 3 (a) to 3 (d).
[0029]
As shown in FIGS. 2A and 2B, the seal member 110 is provided with a circular hole 111 having the same diameter as the inner diameter of the openings of the pipes 101 and 105 at the center. The inner compression portion 112 and the outer compression portion 113 are thin portions at the inner peripheral portion and the outer peripheral portion of the seal member 110, as shown in FIG. The central portion 114 is a portion between the inner compression portion 112 and the outer compression portion 113, and is configured to be thickest and have a larger surface area than both the compression portions 112 and 113. In the present embodiment, as shown in FIG. 2B, the dimensions of each part of the seal member 110 are, for example, an outer diameter B of the seal member 110 of 125 mm, a diameter C of the hole 111 of 75 mm, and a thickness t _1. The thickness t _{2 of} the inner compression portion 112 and the outer compression portion 113 is 1 mm, and the width D is 5 mm.
[0030]
Next, a processing method of the seal member 110 using a Gore-Tex hyper sheet gasket as a material will be described with reference to FIGS. 3 (a) to 3 (d).
[0031]
3A to 3D are cross-sectional views of the seal member for explaining each process.
[0032]
First, the Gore-Tex hyper sheet gasket sheet 301a (see FIG. 3A) is subjected to first compression so as to be ½ of the original thickness T (see FIG. 3B). Here, since the original thickness T is 3 mm, the compressed sheet 301b thickness T / 2 is about 1.5 mm.
[0033]
Next, using a punching die, a ring-shaped plate body 301c (see FIG. 3C) having an outer diameter of 125 mm is punched out from the compressed sheet 301b.
[0034]
Finally, the second compression is further performed from both sides of the inner compression portion 112 and the outer compression portion 113 of the ring-shaped plate-shaped body 301c so that the thickness thereof is about 1 mm (see FIG. 3D). By this second compression, the thicknesses of the inner compression portion 112 and the outer compression portion 113 become about 1/3 of the original thickness. Thereby, each layer of the thin film-like sheet of PTFE resin in the inner side compression part 112 and the outer side compression part 113 of the sealing member 110 is provided with much stronger adhesion.
[0035]
Next, with reference to FIG. 1A and FIG. 1B, the operation when the pipe 101 and the pipe 105 are connected using the above-described components will be described.
[0036]
As shown in FIG. 1B, the seal member 110 is sandwiched between the flange portions 103 and 106 of both the pipes 101 and 105. Then, the flange portions 103 and 106 are firmly secured to each other with an appropriate tightening degree (not shown) so that the inner surfaces of both flange portions 103 and 106 and both surfaces of the seal member 110 are sufficiently adhered to each other. And tighten.
[0037]
The tightening degree in this case can be expressed by the following equation using the thicknesses t ₁ and t ₂ of each part before tightening shown in FIG.
[0038]
[Expression 1]
t ₂ <t ₃ <t ₁
Here, t ₃ is the thickness of the thickest portion of the seal member 110 after tightening, as shown in FIG.
[0039]
Next, with reference to FIGS. 4A and 4B, the leakage of gas can be prevented while comparing the case of the configuration of the present embodiment and the case of the conventional configuration with respect to the connection state of the piping. The reason will be described in more detail. 4A and 4B are sectional views of only the right half because the shape of the seal member is axisymmetric with respect to the central axis 405. FIG.
[0040]
FIG. 4A is a schematic cross-sectional view of the connection structure when the seal member 110 of the present embodiment is used, and FIG. 4B is a seal member having the same configuration as the conventional one (FIG. 3C). FIG. 6 is a schematic cross-sectional view of a connection structure when a ring-shaped plate-like body 301c shown in FIG.
[0041]
FIG. 4A schematically shows a state in which the seal member 110 is formed by laminating five thin film sheets 110a to 110e of PTFE resin for the sake of simplicity.
[0042]
As shown in the figure, each thin film sheet 110a to 110e has a higher degree of compression in the inner compression part 112 and outer compression part 113 than in the central part 114, as described above. is there. Moreover, the degree of compression is such that the thickness t ₂ formed as a result of compression is even thinner than the maximum thickness t ₃ of the seal member 110 after both flange portions 103 and 106 are properly clamped together. Is set to about.
[0043]
In these pipe connections shown in FIGS. 4 (a) and 4 (b), pressurized air was sealed and the presence or absence of leakage was confirmed. The following results were obtained.
[0044]
That is, air pressurized to 3 kg / cm ² leaked from the inner peripheral edge 403 and the outer peripheral edge 404 of the ring-shaped plate 301c shown in FIG. In the configuration of (a), pressure is applied to 7 Kg / cm ² from any of the inner peripheral edge 401, the outer peripheral edge 402, and the contact portion between the central portion 114 and the flange portions 103 and 106 of the seal member 110. There was no leakage against the air. According to the present embodiment, it is estimated that there is no leakage for pressurized air up to about 10 kg / cm ² .
[0045]
Moreover, it can be said from this embodiment that the pressure value of the gas capable of preventing leakage increases as the degree of compression of both compression sections 112 and 113 increases.
[0046]
The leakage was confirmed by a method in which the pressurized air was sealed in the sealed pipe connected as described above, and left for 72 hours, and then the change in the air pressure was examined. Further, the seal member 110 used in this confirmation experiment has been subjected to the processing described with reference to FIGS.
(Embodiment 2)
Next, another embodiment of the seal member of the present invention will be described with reference to FIG. FIG. 5 is a cross-sectional view showing a schematic configuration of the seal member of the present embodiment.
[0047]
In the present embodiment, a configuration of a seal member having a large size used for pipe connection in which the diameter of the flange portion of the pipe is 500 mm or more will be described.
[0048]
Further, in this embodiment, as shown in FIG. 5, a sheet-like sealing member (specifically, a plurality of thin-film sheets made of PTFE resin are laminated and molded to a predetermined thickness as the covering portion 502. Used Japan Gore-Tex Co., Ltd. Gore-Tex Hyper Sheet Gasket). In addition, as the core part 501, the hard non-asbestos 1101 (or asbestos joint sheet) same as the past is used.
[0049]
Here, if an example of the dimension of each part of the sealing member of this Embodiment shown in the figure is given, the hole diameter, the outer diameter, and thickness of the core part 501 are 513 mm, 596 mm, and 2 mm, respectively. Further, the thickness of the covering portion 502 is 1.5 mm. In addition, since the figure shown to the figure is represented typically, the magnitude | size of each part does not respond | correspond to each dimension mentioned above.
[0050]
Further, as shown in the figure, the covering portion 502 is folded back along the both sides of the core portion 501 with a Gore-Tex hyper sheet gasket as a boundary, with the inner peripheral edge portion 503 of the core portion 501 as a boundary. The inner peripheral surface 1104 is not heat-sealed as in the conventional configuration shown in FIG. The reason why such a configuration can be realized is that the flexibility of the Gore-Tex hyper sheet gasket is effectively utilized.
[0051]
In the present embodiment, the Gore-Tex hyper sheet gasket itself used as the covering portion 502 is rich in flexibility as described above, and therefore has excellent conformability to fine uneven portions generated on the flange surface. Compared with the conventional sealing member as described in FIG. 7, since the covering portion 502 is soft, the whole has relatively excellent deformability. Therefore, the effect that the waviness with a large flange surface pitch can be absorbed by the deformation of the seal member itself is exhibited.
[0052]
In the above embodiment, as shown in FIG. 2B, the shape of the seal member is described in the case where the step between the thin portion and the other portion is on both sides of the seal member. However, the present invention is not limited to this. For example, as shown in FIG. 6A, the step 601 may be provided only on one surface of the seal member.
[0053]
In the above embodiment, as shown in FIGS. 2A and 2B, the shape of the seal member is such that both the inner peripheral portion and the outer peripheral portion are thinner than the other portions. However, the present invention is not limited to this. For example, the inner peripheral portion or the outer peripheral portion may be thinner than other portions.
[0054]
In the above embodiment, as shown in FIG. 2A and the like, the shape of the seal member is such that the thin portion is formed in the inner peripheral portion and / or the outer peripheral portion, and that portion is Although the case of a flat surface has been described, the present invention is not limited to this. For example, as shown in FIG. 6B, grooves 602a and 602b having semicircular cross sections are formed on both sides in the vicinity of the inner periphery. It may be configured. Needless to say, the grooves 602a and 602b are formed by the second compression described with reference to FIG. Further, these grooves may be in the vicinity of the outer peripheral portion, in the vicinity of the inner peripheral portion and in the vicinity of the outer peripheral portion, or in the intermediate portion between the inner peripheral portion and the outer peripheral portion. . Further, the cross-sectional shape of the groove is not limited to a semicircular shape, and may be, for example, a U-shape or a V-shape. In short, the joining surface between the laminated thin-film sheets is formed by a normal tightening degree. As long as it is compressed to the extent that it has a bonding force that exceeds the force, and such a compressed part is arranged so as to surround the inside of the pipe, the cross-sectional shape after compression, the location of the compressed part, the compressed part The number of is not questioned.
[0055]
In the above embodiment, as shown in FIG. 2A and the like, the shape of the seal member is such that the thin portion is formed in the inner peripheral portion and / or the outer peripheral portion, and that portion is Although the case where it formed by compression was described, it is not restricted to this, For example, the structure by which the inner peripheral edge part and / or outer peripheral edge part of a ring-shaped plate-shaped object were melt | fused by heat etc. may be sufficient. Thereby, the effect similar to the sealing member of the said structure is exhibited.
[0056]
Moreover, in the said embodiment, although the case where the Gore-Tex hyper sheet gasket of Japan Gore-Tex Co., Ltd. was used as a plate-shaped object was described, it does not restrict to this, For example, the thin film-like sheet | seat which contains a polytetrafluoroethylene resin in a material is mentioned. Any sealing member may be used as long as it is a sealing member that prevents gas leakage of the plate-like body formed by laminating.
[0057]
【The invention's effect】
As is apparent from the above description, the present invention has an advantage that high-pressure gas leakage can also be prevented.
[0058]
In addition, the present invention has an advantage that it can absorb the waviness of the flange surface while being compatible with the flange surface.
[Brief description of the drawings]
FIG. 1A is a cross-sectional view showing a schematic configuration of a pipe connection structure in an embodiment of the connection structure of the present invention. FIG. 1B is a cross-sectional view showing a pipe connection state in the present embodiment. (A): Plan view of the seal member in the present embodiment (b): AA ′ sectional view of the seal member in the present embodiment FIG. 3 (a) to (d): of the present embodiment FIG. 4 is a cross-sectional view of a seal member for explaining a processing step of the seal member. FIG. 4A is a schematic cross-sectional view of a connection structure when the seal member of the present embodiment is used. FIG. 5 is a cross-sectional view showing a schematic configuration of a seal member according to a second embodiment of the present invention. FIG. 6A is a schematic cross-sectional view of a connection structure when a seal member having the configuration is used. Sectional drawing (b) of the 1st modification of the sealing member of 1st Embodiment: 1st Embodiment of this invention FIG. 7 is a cross-sectional view of a conventional gasket covered with a Teflon sheet. FIG. 8 is a characteristic diagram showing the relationship between pressure resistance and heat resistance of a conventional gasket. Explanation of symbols]
101 One piping 103 First flange portion 102 Opening portion 106 of one piping 101 Second flange portion 104 Opening portion 110 of the other piping 105 Sealing member 111 Hole 112 Inner compression portion 113 Outer compression portion 114 Central portion 403 Inside Peripheral part 404 Outer peripheral part 501 Core part 502 Covering part

Claims (10)

A plate-like body formed by laminating thin film sheets containing polytetrafluoroethylene resin as a material, a sealing member for preventing gas leakage,
The plate-like body is a ring-like plate-like body,
The thickness of at least the outer peripheral portion of the ring-shaped plate-like body is thinner than other portions to the extent that the gas does not leak due to pressurization in the stacking direction of the stack, and is in contact with the plate-like body. A sealing member characterized in that the sealing member is set to be thinner than the maximum thickness after tightening the other portions after the flange portions on the side are properly tightened . The thickness of the inner peripheral portion of the front Symbol annular plate-shaped body is, the pressure in the stacking direction of the stack is thinner than the thickness of the other portion except the outer peripheral portion to the extent that the gas tight The sealing member according to claim 1. The shape of the flange portion of the front Symbol phase hand side, characterized in that do not have thick at the thin place and the uneven shape of the uneven shape and fitting formed by the thickness of the plate-like body according to claim 1 The sealing member as described.   2. The sealing member according to claim 1, wherein an area of the plate-like body where the thickness is thick is larger than an area where the thickness is thin. Seal between the flange portion of the front Symbol phase hand side the plate body, the sealing member according to claim 1, wherein the performed at thick thickness of the plate-like body. The sealing member according to any one of claims 1 to 5 , wherein the sealing property against the gas is satisfied when the pressure of the gas is 10 kg / cm ² or less. The sealing member according to any one of claims 1 to 6 , wherein the plate-like body is a Gore-Tex hyper sheet. A first flange formed in the opening of the tubular body;
A second flange portion that fits into the first flange portion;
The seal according to any one of claims 1 to 7 , which is sandwiched between the first flange portion and the second flange portion to prevent leakage of gas existing inside the tubular body. With members,
The connection structure, wherein a shape of the flange portion in contact with the seal member does not have an uneven shape that fits with an uneven shape formed by a thick portion and a thin portion of the seal member. A core that is a ring-shaped plate,
It is formed by laminating a thin film sheet containing polytetrafluoroethylene resin as a material, and includes a seal part softer than the core part,
The seal part is folded back from one surface to the other surface along the inner peripheral edge of the core so as to be along both surfaces of the core.
A sealing member having an outer diameter of 500 mm or more . The seal member according to claim 9 , wherein the seal portion is a Gore-Tex hyper sheet.

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