JPS60188664A - Spiral gasket - Google Patents

Abstract

PURPOSE:To prevent penetration leakage by providing a filler material formed by expansive graphite and filling an auxiliary filler material composed of etylene quadrivalent fluoride resin fiber with which graphite particles are uniformly mixed in a portion closely contacting a curved concave portion of the filler material. CONSTITUTION:In a portion 12a of a filler material 12 closely contacting the curved concave portion 11a of a metallic band plate 11, an auxiliary filler material 13 is spirally and continuously filled, with the auxiliary filler material 13 closely fitted in the curved concave portion 11. Thus, there is no gap or thin density portion to prevent spiral penetration leakage. Besides, as the auxiliary filler material 13 is formed by ethylene quadrivalent fluoride resin fiber with which graphite particles are uniformly mixed, the sliding property for the metallic band plate 11 is excellent, and the graphite particles function as a kind of filling material.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a spiral gasket formed by winding a metal strip with a corrugated cross section and a strip of filler material in a spiral shape multiple times in a state of polymerization. be.

In conventional spiral-wound gaskets of this type, asbestos-type filler materials are often used; In a spiral-wound gas groove using a filler material, under low temperature conditions, the deformability of the filler material decreases and the conformability to the metal strip deteriorates, so that good sealing performance cannot be expected.

Therefore, spiral-wound gaskets using filler material made of expanded graphite have been proposed. Even under these conditions, it is expected to have an excellent sealing function compared to those using asbestos-type filler materials.

However, due to its nature, expanded graphite is brittle and has poor plastic flowability, so when the spiral-wound gasket is compressed during use, the metal strip of the filler material 2, as shown in FIG. There is a possibility that a gap 3 or a low-density portion may occur in the portion 2a that is in close contact with the bending recess 1a. Such a risk occurs to varying degrees regardless of the sealing temperature conditions and even when asbestos filler material is used.

If a gap 3 (or a sparse density area) occurs between the two temperatures 1 and 2 as described above, even though there is no surface leakage from the surfaces 4a and 4b, which are the flange contact surfaces of the gasket. First, a permeation leak occurs in which the sealing fluid leaks from the winding start end of the gasket through the gap 3 in the spiral direction, and the sealing function is not exhibited.

The present invention has been made in view of the above-mentioned points, and provides a spiral-wound customant that can prevent permeation leakage and exhibit a good sealing function even under low-temperature conditions.

The spiral-wound gasket I of the present invention solves this problem,
In particular, the filler material is composed of expanded graphite, and
1, the portions of the filler material that are in close contact with the four bent portions of the metal strip are filled with an auxiliary filler material made of tetrafluoroethylene resin fibers uniformly blended with graphite particles.

Next, an example thereof will be explained with reference to FIG.

The spiral-wound gasket shown in FIG. 2 includes a metal band plate 11 having a dogleg-shaped cross section, a band-shaped filler material 12 made of expanded graphite, and an auxiliary filler material 13 made of tetrafluoroethylene resin fibers uniformly mixed with graphite particles. The auxiliary filler material 1 is arranged along the longitudinal direction of the filler material 12 at the widthwise center of the filler material 12.
3 was closely polymerized and adhered to the metal strip 11 along its longitudinal direction with the auxiliary filler material 13 fitted into the bent recess 11a of the metal strip it, and
These are spirally wound multiple times and formed into a ring shape. In addition, at the inner and outer peripheral parts of the gasket, only the metal band plate 11 is individually wound several times, and the ends are fixed by welding.

The tetrafluoroethylene resin fibers constituting the auxiliary filler material 13 are obtained by, for example, uniformly mixing and stirring unfired tetrafluoroethylene resin powder and graphite particles, and then turning the mixture into fibers by extrusion processing or the like. Graphite particles are uniformly dispersed and blended. In this case, the mixing weight ratio of the graphite particles to the tetrafluoroethylene resin powder is preferably 20 to 80%, and in the above embodiment, it is set to about 20%.

In a spiral-wound gasket having such a configuration, as mentioned at the beginning, gaps or low-density areas that cause seepage leakage are likely to occur, that is, the bent recesses of the metal strip 11 of the filler material 12. 11a, the auxiliary filler material 13 is filled in the bent recess 11a in a rich manner in the spiral direction, so that the above-mentioned gaps or areas with low density do not occur. Therefore, penetration leakage in the thin winding direction is reliably prevented.

Moreover, since the auxiliary filler material 13 is made of tetrafluoroethylene resin fibers uniformly blended with graphite particles, the metal strip t
In addition to having excellent slipperiness against i, the graphite particles function as a kind of plugging material, thus more effectively preventing seepage and leakage.

Furthermore, the expanded graphite constituting the filler material 12 and the tetrafluoroethylene resin containing graphite particles constituting the auxiliary filler material 13 both have superior low-temperature properties compared to asbestos, so they can be used under low-temperature conditions. In particular, it can exhibit a good sealing function even under extremely low temperature conditions.

By the way, the tight puncture performance of the spiral-wound gasket of the present invention under normal temperature conditions and extremely low temperature conditions was compared with a conventional spiral-wound gasket that did not have an auxiliary filler material and used an expanded graphite filler material. As a result of comparative experiments, results as shown in FIGS. 3 and 4 were obtained. In FIGS. 3 and 4, the experimental results for the spiral-wound gasket of the present invention are shown by solid lines, and the experimental results for the conventional spiral-wound gasket are shown by broken lines.

In other words, in the experiment under room temperature conditions, the inner diameter was 125 m.
A ring-shaped gasket with an outer diameter of 145 mm and a thickness of 4.5 mm was tightened between the flanges with a surface pressure of 40'.
After installing it with OKg/crn', helium gas 50
A load of Kg/Ctrl' was applied, and the amount of helium gas leaked from each gasket with respect to the elapsed time after this fluid pressure was applied was measured. The results are shown in FIG.

In addition, in experiments under cryogenic conditions, liquid nitrogen was passed inside the flange, and the temperature near each gasket was 117°C.
Cool to below 0℃, then add 50 ml of helium gas.
A load of K g/cm' was applied, and the amount of helium scum leaking from each gasket was measured with respect to the elapsed time after the fluid pressure was applied. The results are as shown in Figure 54. Note that the experimental conditions other than the above were the same as in the experiment under the above-mentioned hyperthermia condition.

Therefore, as can be easily understood from these experimental results and the above explanation, the spiral force socket of the present invention has the following properties:
Compared to conventional products, it can effectively prevent seepage leakage and exhibit good sealing performance even under low-temperature conditions, especially extremely low-temperature conditions, and its practical value is extremely high. It is what it is.

[Brief explanation of the drawing]

FIG. 1 is a partially cutaway longitudinal side view showing a conventional spiral-wound gasket in a compression use state, and FIG. 2 is a partially cutaway longitudinal side view showing an embodiment of the spiral-wound gasket according to the present invention in a pressure line use state. FIG. 3 is a graph showing the experimental results under normal temperature conditions, and FIG. 4 is a graph showing the experimental results under extremely low temperature conditions. 11...Metal band plate 11a...Four bent parts 12...Filler material 13...Auxiliary filler material Patent applicant: Hiki Biller Kogyo Co., Ltd. Agent: Patent attorney Takashi Suzue - View 1, View 2 + 2a

Claims (1)

[Claims] In a thinly wound gasket formed by winding a metal band plate with a corrugated cross-section and a band-shaped filler material in a spiral shape a plurality of times in a polymerized state, the filler material is composed of expanded graphite and , a spirally wound gasket characterized in that a portion of the filler material that is in close contact with the bent recess of the metal band plate is filled with an auxiliary filler material made of tetrafluoroethylene resin fibers uniformly blended with graphite particles. .