JP4918462B2 - gasket - Google Patents

Description

  The present invention relates to a gasket used for applications that require long-term seal stability in severe use environments such as piping joints (JIS or JPI standard flanges, etc.) and equipment joints (valve bonnets, etc.).

  2. Description of the Related Art Conventionally, a structure in which an expanded graphite sheet is laminated and bonded as a sealing material on both surfaces of a concentric corrugated metal sheet is known. This conventional structure has been achieved by using a thin metal plate with concentric corrugations in the core material, which has previously been a flat metal plate or a metal plate that has been processed into discontinuous irregularities or sawtooth irregularities. The slight compression rate is dramatically increased, and high deformation followability (followability with respect to the flange surface accuracy) that can be used even for a glass lining flange with distortion or undulation is secured. Also, the expanded graphite sheet is used for the sealing material as before, and both surfaces that come into contact with the flange are formed of the expanded graphite sheet. The expanded graphite sheet has high fluidity and ensures excellent conformability to the flange. Yes.

  The mechanism by which such a conventional structure exerts a sealing action will be described with reference to the compression deformation process of the conventional structure shown in FIGS. In the figure, 1 is a thin metal plate with a concentric corrugation that is a core material, 2 and 3 are expanded graphite sheets laminated and bonded to both surfaces of the metal thin plate 1, 4 and 5 are flanges, and T is the gasket thickness.

  In the free state before tightening in FIG. 6 (A), the metal thin plate 1 has the original wave pitch P and wave height T1 / 2 (peak height T1), and the expanded graphite sheets 2 and 3 are also uniform throughout. The gap 4 is formed between the valley 1a of the thin metal plate 1 and the expanded graphite sheets 2 and 3.

  In the tightened state in which the low tightening load is applied as shown in FIG. 6 (B), the metal sheet 1 is compressed in the thickness direction between the opposed flanges 5 and 6, and the wave pitch P is increased while the wave height T1 / 2 is reduced. However, it also stretches and deforms in the surface direction (inner and outer diameter directions) while compressively deforming in the thickness direction. The expanded graphite sheets 2 and 3 are compressed in the thickness direction at the crest 1 b of the metal thin plate 1, but are not compressed at the trough 1 a of the metal thin plate 1. For this reason, the conventional structure ensures a high tightening surface pressure locally at the peak portion 1b of the thin metal plate 1 and exhibits sealing performance. At this time, the expanded graphite sheets 2 and 3 are not deformed due to the high fluidity and follow the change in the position of the crest 1b of the metal thin plate 1, and are reduced while the thickness T2 is reduced by the crest 1b of the metal thin plate 1. 1 is increased at the valley 1a, and a part of the gap 4 is filled.

  In the tightening state in which a high tightening load is applied in FIG. 6C, the metal sheet 1 is further compressed in the thickness direction between the opposing flanges 5 and 6, and the metal sheet 1 further reduces the wave height T1 / 2 while reducing the wave pitch P1 / 2. Is further expanded and further deformed in the plane direction while further compressively deforming in the thickness direction to a state close to a flat plate. At this time, the expanded graphite sheets 2 and 3 are formed by further reducing the thickness T2 at the peak portion 1b of the metal thin plate 1 without further deforming and destroying the position change of the peak portion 1b of the metal thin plate 1 due to its high fluidity. It further increases at the valley 1a of the thin plate 1 and finally fills the entire gap 4. For this reason, in the conventional structure, the expanded graphite sheets 2 and 3 are compressed in the thickness direction even in the valley portion 1a of the metal thin plate 1, and the tightening surface pressure is secured over the entire surface of the peak portion 1b and the valley portion 1a of the metal thin plate 1. Demonstrates stable sealing performance.

Note that a conventional structure in which an expanded graphite sheet is laminated and bonded to both surfaces of a thin metal plate having a concentric corrugated shape is known, for example, in a gasket described in Patent Document 1.
Japanese Utility Model Publication No. 5-92574

  The conventional structure uses an expanded graphite sheet as a sealing material, and thus can be used for a non-oxidizing fluid at 400 ° C. or lower, but is difficult to use for an oxidizing fluid. Then, when inorganic sheets, such as a mica sheet, a vermiculite-type sheet | seat, or a metal sheet, were used as a sealing material, it became clear that there existed the following subjects. The inorganic sheet as described above is a sealing material that can be used for an oxidizing fluid at 400 ° C. or higher.

  That is, since a thin metal plate with concentric corrugations is used as the core material, it is difficult to secure a tightening surface pressure over the entire surface at a low tightening load, and the inorganic sheet is hard and has low compressibility. It is difficult to obtain a practical sealing performance at the tightening load, and when a high tightening load is applied, the inorganic sheet has a significantly lower fluidity than the expanded graphite sheet, and breaks and leaks. If a sufficiently thick inorganic sheet is used, the destruction of the inorganic sheet can be avoided, but such a sufficiently thick inorganic sheet is expensive and the inorganic sheet is hard and has low compressibility. It is difficult to obtain stable sealing performance.

The present invention has been made in view of the above problems, with the purpose to realize a gasket formed by laminating against wearing inorganic sheet on both surfaces of the metal thin plate with a concentric waveform is the central core material, the It is to solve such problems and to secure a stable sealing performance for a long period of time at a low to high tightening load.

The gasket of claim 1 for achieving the above object, a sealing member of the mica powder was filled into a valley sheet metal corrugated concentric, thickness having a sealing property on both sides of the sheet metal 0 .Mica sheet having a thickness of 10 mm or more and 0.50 mm or less is laminated and adhered.

The gasket of claim 2, in gasket according to claim 1, at a density tightening surface pressure in the valleys of the sheet metal is lower than the tightening surface pressure of the ridge portions of the sheet metal, mica powder The sealing material is filled in the valleys of the thin metal plate.

The gasket according to claim 1 or 2 can be compressed with a conventional low tightening load by filling the valley portion of the metal thin plate, which has been a conventional gap, with a sealing material of mica powder and filling the portion from the beginning. compressing the mica sheet in the valleys of which was not metal sheet, it is possible to secure a fastening surface pressure over the entire surface in a load with a low tightening, sealing performance was stable with no practical problem from the load with a low tightening is obtained It is done. Further, it is possible to suppress the deformation amount of the mica sheet, because less liquid mica sheet is not broken even when loaded with high fastening load, a thinner thickness 0.10mm or 0.50mm less mica Sea Can be used.

Further, since the sealing material on both sides of the sheet metal is disposed in two layers, even if the mica sheet is outside of the sealing material was broken, but may be sealed by mica powder is an inner sealant, the seal Increased reliability .

  Furthermore, since the sealing material filled in the valleys of the metal thin plate is powder and has both high compressibility and high fluidity, the deformation of the metal thin plate is not hindered and the deformation followability of the gasket is not impaired. It is difficult to generate a gap in the valley portion of the metal thin plate, and the clamping surface pressure can be stably secured in the portion. The powder sealing material is inexpensive and can be used without waste at a high yield and is economical.

As in the gasket according to claim 2 , the sealing material of mica powder is used to form a valley of the metal thin plate at a density such that the clamping surface pressure at the valley of the metal thin plate is lower than the clamping surface pressure at the peak of the metal thin plate. By filling the portion, the tightening surface pressure distribution is not uniform and the tightening surface pressure does not decrease, so that the minimum tightening force required for sealing does not increase.

According to the gasket of claim 1, 2, realizing a gasket formed by laminating against wear following mica sheet thickness 0.10mm or 0.50mm on both surfaces of the metal thin plate with a concentric waveform is the central core member In addition, it is possible to ensure a long-term stable sealing performance at low to high tightening loads.

According to the gasket of the second aspect , the strength of the required joint portion of the equipment / pipe is not increased in use, and there is no need for a review of the design and modification of the equipment / device.

  Hereinafter, embodiments of a gasket according to the present invention will be described with reference to the drawings. FIG. 1 is a plan view of a gasket according to an embodiment of the present invention, and FIG. 2 is a cross-sectional view showing the structure of the gasket according to an embodiment of the present invention.

  A gasket 10 shown in FIGS. 1 and 2 is an annular ring having sealing properties on both front and back surfaces of an annular thin metal plate (hereinafter referred to as “corrugated thin metal plate”) 11 having a concentric corrugation as a core material. Is a gasket obtained by laminating and bonding the inorganic sheets 12 and 13, and the portion that is the conventional gap 4 (see FIG. 6) (between the valley 11 a of the corrugated metal sheet 11 and the inorganic sheets 12 and 13) By compressing the inorganic sheets 12 and 13 in the trough portion 11a of the corrugated metal sheet 11 that could not be compressed with a load, the tightening surface pressure is secured over the entire surface at a low tightening load, and a stable sealing performance from the low tightening load is achieved. In order to suppress the amount of deformation of the inorganic sheets 12 and 13, prevent the inorganic sheets 12 and 13 having low fluidity from breaking, and enable the use of thinner inorganic sheets 12 and 13, sticker (Hereinafter, referred to as "filler".) 14 is filled, fill a portion conventionally space 4 from the beginning by the filler 14. Therefore, the gasket 10 has a structure in which the filler 14 as the sealing material and the inorganic sheets 12 and 13 are arranged in two layers on the front and back sides of the corrugated metal sheet 11.

  Here, the inner peripheral edge and the outer peripheral edge of the corrugated metal thin plate 11 are located on one plane including the apex of each peak portion 11b projecting to one side of the corrugated metal thin plate 11 (the lower side in FIG. 2). Circular flat portions 11c and 11d are formed. Further, the outer shape of the front and back surfaces of the corrugated metal thin plate 11 after the filler 14 is filled in the valley portion 11a is the surface of the flat portions 11c and 11d whose outer surfaces (upper side in FIG. 2) are located on the same plane. Is a three-dimensional shape that rises into a trapezoid with a low profile, and the outer shape of the back surface (the lower side in FIG. 2) is a planar shape in which the back surfaces of the flat portions 11c and 11d located on the same plane are connected by a flat surface. It has become. Then, the inorganic sheet 12 on the surface side of the corrugated metal sheet 11 is formed on the surface of the corrugated metal sheet 11 from the end of the flat part 11c on the inner peripheral side to the end of the flat part 11d on the outer peripheral side. The inorganic sheet 13 on the back side of the corrugated metal thin plate 11 is laminated and adhered along the outer shape of the shape, and extends from the end of the flat portion 11c on the inner peripheral side of the corrugated metal thin plate 11 to the end of the flat portion 11d on the outer peripheral side. The corrugated metal thin plate 11 is laminated and adhered along the outer shape of the planar shape on the back surface. The inner peripheral edges of the inorganic sheets 12 and 13 protrude in the inner diameter direction from the end of the flat portion 11c on the inner peripheral side of the corrugated metal sheet 11, and the flat portion 11c on the inner peripheral side from the end of the flat portion 11c. It is stuck and fixed within the thickness of. The outer peripheral edges of the inorganic sheets 12 and 13 protrude in the outer diameter direction from the end of the flat portion 11d on the outer peripheral side of the corrugated metal sheet 11, and the thickness of the flat portion 11d on the outer peripheral side from the end of the flat portion 11d. It is stuck and fixed inside.

The gasket 10 is manufactured by holding the corrugated metal sheet 11, which is a press-molded product, in a substantially horizontal posture, filling the valleys 11 a on the upper surface side of the corrugated metal sheet 11 with the filler 14, and then forming the corrugated metal sheet 11. One inorganic sheet 12 is laminated and bonded to the upper surface (surface) via an adhesive (not shown). Next, the corrugated metal thin plate 11 is turned over, and after filling the valleys 11a on the upper surface side of the corrugated metal thin plate 11 with the filler 14, the other inorganic sheet 13 is bonded to the upper surface (back surface) of the corrugated metal thin plate 11 (not shown). completing the laminating adhesive through the agent monitor, by fixing alignment bonded to the inner peripheral edge between the outer peripheral edge between the inorganic sheet 12, and 13.

  At this time, filling is performed at a density lower than the density of the inorganic sheets 12 and 13 so that the tightening surface pressure in the valley portion 11a of the corrugated metal sheet 11 is lower than the tightening surface pressure in the peak section 11b of the corrugated metal sheet 11. It is important to fill the valleys 11 of the corrugated metal sheet 11 with the material 14. By filling the filler 14 with such a density, in the gasket 10, the filler 14 (low density) and the inorganic sheets 12 and 13 (high density) which are sealing materials having different densities on the front and back surfaces of the corrugated metal sheet 11 are used. ) Are arranged in two layers inside and outside.

  FIG. 3 is a cross-sectional view showing the structure of a gasket according to another embodiment of the present invention. In addition, the plane of the gasket which concerns on this embodiment is the same as the plane shown in FIG. Moreover, since the structure of the gasket which concerns on this embodiment is the same as the structure shown in FIG. 2 of the said gasket 10 except an inorganic sheet, the same code | symbol is attached | subjected to the same structure and detailed description is abbreviate | omitted.

  The gasket 20 shown in FIG. 3 is obtained by continuously covering the front and back surfaces and the inner periphery of the corrugated metal thin plate 11 with an integrally formed metal molded body 21 produced by cutting an annular metal flat plate. . The metal molded body 21 includes annular sheet portions 21a and 21b that are opposed in the thickness direction, and a short cylindrical connecting portion 21c that is integrally formed between the inner peripheral side edges of the sheet portions 21a and 21b. A core storage space 21e having an opening 21d on the outer periphery is formed inside the connecting portions 21c and the sheet portions 21a and 21b. The corrugated metal thin plate 11 is mounted in the core housing space 21e, and the front and back both sides of the corrugated metal thin plate 11 from the upper and lower ends of the connecting portion 21c rising immediately inside the flat portion 11c on the inner peripheral side of the corrugated metal thin plate 11 Sheet portions 21a and 21b are extended.

  The gasket 20 is manufactured by holding the metal molded body 21 in a horizontal posture, lifting one sheet portion 21a on the upper surface side on the same cylindrical surface as the connecting portion 21c, and lifting the corrugated metal thin plate 11 from above into a cylindrical sheet. After being fitted to the outside of the connecting portion 21 c through the portion 21 a, the filling material 14 is filled into each trough portion 11 a on the upper surface side of the corrugated metal thin plate 11. Next, the cylindrical sheet portion 21a is returned to the original, and laminated and bonded to the upper surface (front surface) of the corrugated metal thin plate 11 via an adhesive (not shown). Next, the corrugated metal thin plate 11 is turned over, and the other sheet portion 21b on the upper surface side is raised on the same cylindrical surface as the connecting portion 21c, and then the filler 14 is applied to each trough portion 11a on the upper surface side of the corrugated metal thin plate 11. Fill. Next, the cylindrical sheet portion 21b is returned to its original position, and is completed by laminating and bonding the upper surface (back surface) of the corrugated metal thin plate 11 with an adhesive (not shown). In this case, it is important that the filling material 14 is filled in the valley portion 11 of the corrugated metal sheet 11 at a density lower than that of the metal molded body 21 in the same manner as the gasket 10. .

  In the case of the gasket 20, a gap is formed in the inner corner of the inner periphery (between the flat portion 11c of the corrugated metal thin plate 11 and the inner peripheral edge of one sheet portion 21a). The material 14 is filled to fill the gap.

  Since the gaskets 10 and 20 configured as described above have the same mechanism for exerting a sealing action, description will be given with reference to the compression deformation process of the gaskets 10 and 20 shown in FIGS. .

  In FIG. 4, 50 and 60 are flanges of equipment and piping, and t is the gasket thickness.

  In the free state before tightening in FIG. 4 (A), the corrugated metal sheet 11 has the original wave pitch p and wave height t1 / 2 (peak height t1). The sheet portions 21a and 21b also have a uniform original thickness t2 as a whole, and in the portion (between the trough portion 11a of the corrugated metal thin plate 11 and the inorganic sheets 12 and 13 and the metal molded body 21) that has been the air gap 4 in the past. The filler 14 is filled.

  In the tightened state in which the low tightening load shown in FIG. 4B is applied, the gaskets 10 and 20 are compressed in the thickness direction between the opposing flanges 50 and 60, and the corrugated metal sheet 11 reduces the wave height t1 / 2. While expanding the wave pitch p, it is also deformed in the surface direction (inner / outer diameter direction) while compressively deforming in the thickness direction. The sheet portions 21 a and 21 b of the inorganic sheets 12 and 13 and the metal molded body 21 are compressed in the thickness direction by the crest portions 11 b of the corrugated metal thin plate 11, and the trough portions 11 a of the corrugated metal thin plate 11 are filled with the filler 14. As a result, the corrugated metal sheet 11 is compressed even in the valley 11a, and the tightening surface pressure is secured over the entire surface of the crest 11b and the valley 11a of the corrugated metal sheet 11 to exhibit stable sealing performance.

  4C, the gaskets 10 and 20 are further compressed in the thickness direction between the opposing flanges 50 and 60, and the corrugated metal sheet 11 further increases the wave height t1 / 2. The wave pitch p is further enlarged while being reduced, and further stretched and deformed in the surface direction while further compressively deforming in the thickness direction to a state close to a flat plate. The sheet portions 21 a and 21 b of the inorganic sheets 12 and 13 and the metal molded body 21 are further compressed in the thickness direction by the crest portions 11 b of the corrugated metal thin plate 11, and the filler 14 is formed in the valley portions 11 a of the corrugated metal thin plate 11. Since it is filled, it is further compressed even in the valley 11a of the corrugated metal sheet 11, ensuring a higher clamping surface pressure on the entire surface of the crest 11b and the valley 11a of the corrugated metal sheet 11, and a low clamping load. Continue to maintain the stable sealing performance obtained in.

  Thus, in each gasket 10 and 20, since the filling material 14 is filled in the valley portion 11a of the corrugated metal thin plate 11 which has been the gap 4 in the past and the portion is buried from the beginning, it can be compressed with the conventional low tightening load. Since the inorganic sheets 12 and 13 in the trough portion 11a of the corrugated metal thin plate 11 and the sheet portions 21a and 21b of the metal molded body 21 can be compressed and a tightening surface pressure can be secured over the entire surface with a low tightening load. Stable sealing performance can be obtained from low tightening load. Therefore, it is possible to ensure a long-term stable sealing performance at low to high tightening loads.

Moreover, in each gasket 10 and 20, since the trough part 11a of the corrugated metal thin plate 11 which was the space | gap 4 conventionally is filled with the filler 14, and this part is buried from the beginning, the inorganic sheets 12 and 13 and the metal molded body 21 are filled. There order to suppress the deformation of an attempt to fill the valley portion 11a of the corrugated metal sheet 11 by its fluidity and thickness t 2, the amount of deformation of the seat portions 21a and 21b of the inorganic sheet 12 and 13 and metal forming body 21 Very small. For this reason, since the inorganic sheets 12 and 13 and the metal molded body 21 having low fluidity do not break even when a high tightening load is applied, the thinner inorganic sheets 12 and 13 and the metal molded body 21 can be used.

  Moreover, in each gasket 10 and 20, the filler 14 which is a sealing material, the inorganic sheets 12 and 13, and the sheet | seat parts 21a and 21b of the metal molded body 21 are arrange | positioned in two layers inside and outside on the front and back of the corrugated metal thin plate 11. Since it has a structure, even if the inorganic sheets 12 and 13 and the metal molded body 21 which are the outer sealing materials are broken, the sealing can be performed by the filler 14 which is the inner sealing material, and the reliability of the sealing is improved. high. The filler 14 as the inner seal material, the inorganic sheets 12 and 13 as the outer seal material, and the metal molded body 21 can be the same material or a combination of different materials.

  Moreover, in each gasket 10 and 20, since the filler 14 with which the trough part 11a of the corrugated metal sheet 11 is filled is a powder and has both high compressibility and high fluidity, the trough part 11a of the corrugated metal sheet 11 is obtained. Since the corrugated metal sheet 11 is compressed and flows in the valley portion 11a of the corrugated metal sheet 11 with good followability, the deformation of the corrugated metal sheet 11 is not disturbed and the deformation followability of the gaskets 10 and 20 is not impaired. It is difficult to generate a gap in the valley portion 11a of the corrugated metal sheet 11, and the tightening surface pressure can be stably secured in the portion. The powder filler 14 is inexpensive and can be used without waste at a high yield and is economical.

  Further, in each gasket 10, 20, the filling material 14 is filled in the valley portion 11 of the corrugated metal thin plate 11 at a density lower than the density of the inorganic sheets 12 and 13 and the metal molded body 21. In this case, the tightening surface pressure at the valley portion 11a of the corrugated metal sheet 11 is lower than the tightening surface pressure at the peak portion 11b of the corrugated metal sheet 11, and the tightening surface pressure distribution is not uniform and the tightening surface pressure is increased. Since it does not decrease, there is no increase in the minimum tightening force required for sealing. Therefore, in use, the required strength of the joints of equipment and piping does not increase, and there is no need for a review of the design and modification of facilities and equipment.

  As described above, the gaskets 10 and 20 ensure compatibility with the inorganic sheets 12 and 13 and the metal molded body 21 having low fluidity, and realize the use of the inorganic sheets 12 and 13 and the metal molded body 21. Therefore, a mica sheet, a vermiculite sheet, a metal sheet or the like can be used as the inorganic sheet, and it can be used for an oxidizing fluid at 400 ° C. or higher. In this application, powder such as mica and talc (inorganic mineral) can be used as the filler 14.

  Further, the corrugated metal sheet 11 can be used for the above applications as long as it is a metal sheet such as copper, iron, mild steel, stainless steel, and aluminum in consideration of the temperature of the internal fluid and the corrosion resistance with the internal fluid. is there.

  Corrugated metal thin plate 11 (material: stainless steel [316L], plate thickness: 0.5 mm, wave pitch p: 3.2 mm, wave height t1 / 2: 0.55 mm [mountain height t1: 1.1 mm] 1), mica sheets (thickness t2: 0.5 mm) are used as the inorganic sheets 12 and 13, and mica powder (average particle size: 50 μm) is used as the filler 14, and shown in FIGS. Such a gasket (hereinafter referred to as “Example”) was produced.

  As a comparative example of the example, a gasket having the same structure as the example (hereinafter referred to as “comparative example”) was prepared except that the filler 14 was not filled.

  FIG. 5 shows the sealing characteristics of the example and the comparative example. FIG. 5 shows a nitrogen gas seal test at room temperature for the example and the comparative example, and the respective seal characteristics are compared. In FIG. 5, the example is superior in sealing performance at a low to high tightening load (surface pressure) as compared with the comparative example. In the comparative example, the inorganic sheets 12 and 13 were broken and leaked at a high tightening load. Thereby, by filling the valley portion 11a of the corrugated metal sheet 11 that has been the conventional gap 4 with the filler 14 and filling the portion from the beginning, it is possible to secure a stable sealing performance for a long period of time with a low to high tightening load. In addition, it was confirmed that the inorganic sheets 12 and 13 and the metal molded body 21 made of a material having low fluidity can be used in a high tightening load.

  Table 1 below shows the relationship between the thicknesses of the inorganic sheets 12 and 13 (mica sheets) and the sealing performance of the examples and comparative examples.

  Table 1 shows a nitrogen gas seal test in which the thicknesses of the inorganic sheets 12 and 13 are changed for the examples and comparative examples, and the sealing performance for each thickness is compared. In Table 1, in Examples, stable sealing performance was obtained with inorganic sheets 12 and 13 having a standard thickness t2, which was not obtained in the comparative example. In this way, the filler 14 is filled in the valley portion 11a of the corrugated metal thin plate 11 which has been the conventional gap 4, and the portion is filled from the beginning, so that the inorganic sheets 2 and 13 and the metal molded body 21 which are thinner with a standard thickness. It was confirmed that it can be used.

It is a top view of the gasket concerning the embodiment of the present invention. It is sectional drawing which shows the structure of the gasket which concerns on embodiment of this invention. It is sectional drawing which shows the structure of the gasket which concerns on other embodiment of this invention. It is a figure which shows the compression deformation process of the gasket which concerns on embodiment of this invention and other embodiment. It is a line graph which shows the sealing characteristic of the Example and comparative example of this invention. It is a figure which shows the compression deformation process of the conventional gasket structure.

1 0 Gasket 11 Corrugated sheet metal (metal sheet)
11a Valley 11b Mountain 12,13 Inorganic sheet 14 Filler (sealant)
20 Gasket 21 Metal molding

Claims (2)

The concentric corrugated metal sheet is filled with a mica powder sealing material in the valleys, and the mica sheet having a sealing property on both sides of the metal sheet is laminated and bonded. Characteristic gasket. The mica powder sealing material is filled in the valley of the metal thin plate at a density such that the clamping surface pressure in the valley of the metal thin plate is lower than the clamping surface pressure in the peak of the metal thin plate. The gasket according to 1 .

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