JPH0719342A - Gasket - Google Patents

Abstract

PURPOSE:To improve the permeable leakage preventing function while the reduction in various properties inherent to a gasket such as heat resistance, load resistance, chemical resistance, and the like are suppressed, and substantially improve the sealing ability to seal out especially gas, solvents, hot oil, etc., on the whole, which is also excellent in the contact surface-leakage preventing function. CONSTITUTION:Circular ring-like divided gasket sheets 1, 2 differed from each other in diameter are concentrically arranged in the same plane, and a ring-like clearance 3 formed between the inner and outer peripheral surfaces of both the divided gasket sheets 1, 2 is plugged with impermeable material such as a sealant 4, an adhesive material or a ring-like sealing body, and the like to form both the divided gasket sheets 1, 2 into an integral unit.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gasket used as a sealing material for joints of various fluid devices, pressure vessels, pipes and the like, and is particularly suitable for preventing leakage of gas, solvent, hot oil, etc. It concerns gaskets.

[0002]

2. Description of the Related Art As a gasket of this type, one commonly used in the past, as shown in FIG. 10, is a paper gasket / beater sheet manufactured by a papermaking method, and a joint manufactured by a hot roll method. Sheet or sheet-like sealing material 20 such as expanded graphite sheet or porous PTFE
Gasket 21 stamped into a desired size and shape
Alternatively, as shown in FIG. 11, an annular sheet-shaped sealing layer 2 made of expanded graphite is formed on both surfaces of the annular metal thin plate 22.
A gasket 24 formed by forming 3, 23 is known.

Further, there are also known general gaskets having various measures against leakage. One of them is disclosed in JP-A-56-167960,
Further, as shown in FIG. 12, the sealant 25, 25 is applied to both front and back surfaces of the sheet-shaped sealing material 20 and baked,
In addition, as disclosed in Japanese Utility Model Laid-Open No. 59-188350, there is a sheet-shaped sealing material in which a part is locally compressed to form a dense portion.

[0004]

However, in the above-mentioned conventional general gasket, the sheet-shaped sealing material 20 and the annular sheet-shaped sealing layer 23 are the same as those shown in FIGS.
Since it is formed from multiple parallel layers as shown in enlarged form, when pressurized from the inner diameter side, as shown by the arrow, fluid passes through the layers and leaks to the outer diameter side. The occurrence of mobile seepage leaks is unavoidable. In particular,
Gas such as gas with small molecular weight or solvent with high permeability,
It is difficult to prevent permeation leakage of hot oil and the like.

In addition, although the former of the gaskets having the leakage countermeasure is excellent in the function of preventing the leakage of the contact surface with the flange or the like, it has a sufficient effect in the function of preventing the permeation leakage as described above. I can't get it. Also, with the latter, even if locally compressed to form a dense part, it is not possible to completely eliminate the minute gaps between the parallel layers, and therefore prevent permeation leakage of gas, solvent, hot oil, etc. Was insufficient.

The present invention has been made in view of the above-mentioned circumstances, and is intended to improve the permeation leakage prevention function while suppressing deterioration of various original properties such as heat resistance, load resistance, and chemical resistance, and to improve the contact surface. It is an object of the present invention to provide a gasket which has an excellent leak prevention function and can significantly improve the sealing property as a whole particularly against gas, solvent, hot oil and the like.

[0007]

In order to achieve the above object, the gasket according to the invention of claim 1 is such that annular split gasket sheets having different diameters are arranged concentrically in the same plane, and An annular gap is formed between the inner and outer peripheral surfaces of the divided parts of the divided gasket sheet, and the annular gap is filled with an impermeable substance to integrate the divided gasket sheets.

Further, in the gasket according to the second aspect of the present invention, an annular sheet-like seal layer having an inner and outer diameters equal to those of the annular reinforcing plate is formed on both surfaces of the impermeable annular reinforcing plate. , Each of these sheet-like seal layers is formed with a circular annular groove continuous in the radial middle portion thereof, respectively, and the annular reinforcing plate and the annular reinforcing plate are filled with an impermeable substance in these annular grooves. The sheet-like seal layers on both sides are integrated.

A sealant or an adhesive may be used as the impermeable substance in the gasket according to the invention of claim 1 and / or claim 2.
A ring-shaped seal member formed by winding a tape-shaped sealing material in a spiral or concentric shape may be used.

[0010]

According to the invention of claim 1, an impermeable substance is filled in the gap between the inner and outer peripheral surfaces of the divided parts of the divided gasket sheets arranged concentrically, and the impermeable part is formed in the middle part in the radial direction of the gasket. Since the sheet is formed, it is possible to reliably prevent the fluid passing between the layers of the sheet from being blocked by the impermeable portion and leaking out to the outer diameter side of the gasket, that is, permeating leakage. Further, since the impermeable portion may be extremely thin, it is possible to minimize deterioration of various properties such as heat resistance, load resistance, and chemical resistance that the gasket sheet originally has. Furthermore, the impermeable portion locally generates a large pressure during tightening, and it is possible to effectively prevent contact surface leakage.

According to the second aspect of the present invention, it is possible not only to reliably prevent permeation leakage in the sheet-shaped seal layers formed on both sides of the annular reinforcing plate, but also to prevent the sheet-shaped seals from leaking. The strength reduction due to the layers being divided in the radial direction can be compensated for by the reinforcing effect of the annular reinforcing plate, so that it is possible to exert an excellent sealing property while having sufficient strength as a whole.

The sealant used as the impermeable substance in the gasket according to the first and / or the second aspect of the present invention is a nitrile rubber type, neoprene rubber type, silicone rubber type, polyurethane rubber type,
Phenolic resin type, vinyl resin type, polyamide resin type,
It is preferable to use a PTFE resin system or the like in which various inorganic fillers such as talc, graphite, expansive graphite, sepiolite and short fibers are mixed with these base materials,
As the adhesive, a resin adhesive such as an epoxy type or a phenol type is preferable. Further, expanded graphite, porous PTFE and the like are conceivable as the constituent material of the tape-shaped sealing material.

[0013]

Embodiments of the present invention will be described below with reference to the drawings. Example 1: As shown in FIG. 1, a ring-shaped split gasket having an inner diameter d11 of 90 mm and an outer diameter d12 of 110 mm is obtained by punching a sheet-shaped sealing material such as an expanded graphite sheet having a thickness t of 1.5 mm. Seat 1 and inner diameter d21 is 11
An annular split gasket sheet 2 having an outer diameter d22 of 2 mm and an outer diameter d22 of 130 mm is prepared, and these two annular split gasket sheets 1 and 2 having different diameters are concentrically arranged in the same plane to divide the two. An annular gap 3 having a width of 1 mm is formed between the inner and outer peripheral surfaces of the gasket sheets 1 and 2, and the annular gap 3 is filled with a sealant 4 as an impermeable substance so that the split gasket sheets 1 and 2 are integrated. It will be made.

Embodiment 2 As shown in FIG. 2, the thickness t2 is 1 mm and the inner diameter d31 is on both sides of the impermeable annular reinforcing plate 5 made of a stainless steel plate having a thickness t1 of 0.05 mm. An annular sheet-shaped seal layer 6, 6 made of an expanded graphite sheet having a diameter of 90 mm and an outer diameter d32 of 120 mm is formed, and a radial intermediate portion (diameter d33 = 105 mm) of both seal layers 6, 6 is formed. A ring-shaped groove 7, 7 having a width of about 1 mm and continuous in the circumferential direction is formed, and each of the ring-shaped grooves 7, 7 contains P as an impermeable substance.
The TFE pastes 8 and 8 are filled to integrate the annular reinforcing plate 5 and the sealing layers 6 and 6 on both sides.

Example 3: As shown in FIG. 3, a sheet-shaped sealing material such as an expanded graphite sheet having a thickness t of 1.5 mm was punched to have an inner diameter d11 of 90 mm and an outer diameter d12 of 1.
10 mm annular split gasket sheet 1 and inner diameter d
21 is 120 mm and an outer diameter d22 is 140 mm, and an annular split gasket sheet 2 is created, and these two annular split gasket sheets 1 and 2 having different diameters are concentrically arranged in the same plane, An annular gap 3 having a width of 5 mm is formed between the inner and outer peripheral surfaces of the divided gasket sheets 1 and 2, and a tape-like sealing material such as expanded graphite is used as an impermeable substance in the annular gap 3 as shown in FIG. Inner diameter d4 by winding in a spiral shape or in a concentric shape as shown in FIG.
1 is 110 mm and the outer diameter d42 is 120 mm, and a ring-shaped seal body 9 is inserted and integrally formed by pressing.

Embodiment 4 As shown in FIG. 4, the sealing grooves 6 and 6 in the above-mentioned Embodiment 2 are respectively made of expanded graphite or the like in the annular grooves 7 and 7 as shown in FIG. 5 or 6. The ring-shaped seal bodies 9 and 9 are inserted and fitted to form the annular reinforcing plate 5.
And the sealing layers 6 and 6 on both sides are integrally molded under pressure.

In each of the gaskets shown in the above-mentioned embodiments, the sealant 4 and P are provided in the radial middle portion.
Since the impermeable portion is formed by the TFE paste 8 and the ring-shaped sealing body 9, for example, FIG. 7 showing an enlarged main portion of the first embodiment and FIG. 8 showing an enlarged main portion of the fourth embodiment. Obviously, the fluid passing between the sheet layers as shown by the arrows will be stopped at the impervious portion, and the leakage to the outer diameter side of the gasket, that is, the permeation leakage is reliably prevented. . Further, since the impervious portion may be extremely thin, deterioration of various properties such as heat resistance, load resistance, and chemical resistance that the gasket sheets 1 and 2 and the sheet layer 6 originally have is minimal. Can be suppressed to further,
The impermeable portion locally generates a large pressure during tightening, and the contact surface leakage prevention function can be effectively exerted.

FIG. 9 shows the gasket of the first embodiment, FIG.
FIG. 13 is a diagram showing sealing characteristic results by a gas seal test performed on the conventional gasket of FIG. The specifications of the sample gasket specified for the test are 90 mm inside diameter, 130 mm outside diameter, and 1.5 mm thick.
mm, N ₂ gas was used as a test gas, and the pressure was set to 21 Kgf / cm ² . In the figure, the solid line shows the sealing characteristics of the gasket of Example 1, the one-dot chain line shows the sealing characteristics of the conventional gasket of FIG. 10, and the two-dot chain line shows FIG.
The sealing characteristics of No. 2 conventional gaskets are shown respectively.

As is clear from the results of the sealing characteristics obtained by the gas seal test shown in FIG. 9, in the case of the product of the embodiment of the present invention, the leakage amount (cc) increases as the tightening surface pressure (Kgf / cm ² ) increases. / Min) sharply decreases, and when the tightening surface pressure exceeds a certain level, leakage can be almost completely prevented. On the other hand, in the case of conventional products, the tightening surface pressure (K
Even if the tightening surface pressure was such that the leakage of the product of Example of the present invention was zero, the rate of decrease in the amount of leakage with the increase of gf / cm ² ) was small, and a considerable amount of leakage was observed. It is clear that this is due to permeation leakage between the layers of the sheet, as already mentioned.

[0020]

As described above, according to the first aspect of the invention, the gap between the inner and outer peripheral surfaces of the divided parts of the divided gasket sheets arranged concentrically is filled with an impermeable substance, and the gasket is diametrically oriented. Since the impermeable portion is formed in the intermediate portion of the sheet, the fluid passing between the layers of the sheet can be stopped at the impermeable portion, and the permeation leakage can be reliably prevented.
In particular, it is effective for preventing permeation leakage of gas such as gas having a small molecular weight, solvent having high permeability, hot oil and the like. Further, since the impervious portion may be extremely thin, it is possible to minimize the deterioration of various properties such as heat resistance, load resistance, and chemical resistance that the gasket sheet originally has, and It is possible to exert an excellent function of preventing permeation leakage. Further, since a large pressure is locally generated in the impermeable portion during tightening, leakage of the contact surface can be prevented, and the sealability as a whole can be significantly improved.

According to the second aspect of the present invention, not only can the permeation leakage in the sheet-shaped seal layers formed on both sides of the impermeable annular reinforcing plate be reliably prevented, but also in the radial direction. Since the sheet-shaped seal layer divided by the above can be reinforced by the annular reinforcing plate, it has sufficient strength as a whole, ensures permeation leakage prevention, and exhibits an excellent sealing property.

[Brief description of drawings]

FIG. 1 is a vertical sectional view showing a gasket according to a first embodiment of the present invention.

FIG. 2 is a vertical sectional view showing a gasket according to a second embodiment of the present invention.

FIG. 3 is a vertical sectional view showing a gasket according to a third embodiment of the present invention.

FIG. 4 is a vertical sectional view showing a gasket according to a fourth embodiment of the present invention.

FIG. 5 is a perspective view showing an example of a ring-shaped seal body used in the above embodiment.

FIG. 6 is a perspective view showing another example of the ring-shaped seal body used in the above embodiment.

FIG. 7 is an enlarged vertical cross-sectional view of a main part showing a permeation leakage behavior in the gasket according to the first embodiment.

FIG. 8 is an enlarged vertical cross-sectional view of a main part showing a permeation leakage behavior in the gasket according to the fourth embodiment.

FIG. 9 is a diagram showing a result of sealing characteristics by a gas seal test performed on Example 1 and a conventional gasket.

FIG. 10 is a vertical sectional view showing an example of a conventional general gasket.

FIG. 11 is a vertical cross-sectional view showing another example of a conventional general gasket.

FIG. 12 is a vertical cross-sectional view showing another conventional gasket.

FIG. 13 is an enlarged vertical cross-sectional view of a main part showing a permeation leakage behavior in the conventional general gasket shown in FIG.

FIG. 14 is an enlarged vertical cross-sectional view of a main part showing a permeation leakage behavior in the conventional general gasket shown in FIG.

[Explanation of symbols]

 1, 2 split gasket sheet 3 gap 4 sealant (impermeable substance) 5 annular reinforcing plate 6 sheet-shaped sealing layer 7 groove 8 PTFE paste (impermeable substance) 9 ring-shaped sealing body (impermeable substance)

Claims (4)

[Claims] 1. An annular split gasket sheet having different diameters is arranged concentrically in the same plane, and an annular gap is formed between the inner and outer peripheral surfaces of the split portions of these split gasket sheets. A gasket obtained by filling an impermeable substance with the above-mentioned divided gasket sheets and integrating them. 2. An annular sheet-like seal layer having an inner diameter and an outer diameter equal to that of the annular reinforcement plate is formed on both surfaces of the impermeable annular reinforcement plate, and these sheet-like seal layers are radially arranged. To form an annular groove continuous in the circumferential direction in the middle portion of each, and to fill the annular groove with an impermeable substance to integrate the annular reinforcing plate and the sheet-like sealing layers on both sides thereof. Become a gasket. 3. The gasket according to claim 1, wherein the impermeable substance is a sealant or an adhesive. 4. The gasket according to claim 1, wherein the impermeable substance is a ring-shaped sealing body formed by winding a tape-shaped sealing material in a spiral or concentric shape.