JPH0410201Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a gasket used under high temperature and high pressure.

[Conventional technology]

It is well known that graphite gaskets have been widely used under high temperature and high pressure conditions.

For this reason, gaskets having various structures and methods for manufacturing the same have been developed.

All of these use expanded graphite powder as the main material.

For example, a method of filling a portion of a metal reinforcing plate with wire mesh or protrusions that requires high surface pressure with a larger amount of gasket material than other portions (Japanese Patent Laid-Open No. 56-73264
(No. Publication), a material in which fibrous metal reinforcing material having an appropriate size is dispersed between particles of expanded graphite,
Pressure molding method after filling the mold (JP-A-Sho)
60-73171) has been adopted.

In addition, a method of incorporating one or more reinforcing plates of the same shape as the gasket into expanded graphite (Japanese Patent Application Laid-Open No. 1989-1999-
No. 101360) has been disclosed.

However, these gaskets have drawbacks in terms of resistance to high temperatures and high pressures, and the method of JP-A-60-101360 has poor adhesion between expanded graphite and metal plates, and is susceptible to extreme pressures due to repeated high and low pressures or negative pressures. The disadvantage is that the layers may peel off due to fluctuations.

Furthermore, conventional gaskets are made of powdered expanded graphite and are molded under pressure, so they have the disadvantage of creating a poor working environment.

[The problem that the idea aims to solve]

The present invention provides a gasket that is resistant to high temperatures and pressures, has good adhesion between expanded graphite and metal plates, has high strength, and does not degrade the working environment during production.

[Means to solve the problem]

It is better to use powdered expanded graphite than gaskets obtained by reinforcing powdered expanded graphite with fibrous metal and molding them, or gaskets in which one or more reinforcing plates of the same shape as the gasket are included in expanded graphite. A gasket obtained by molding an expanded graphite sheet and laminating the obtained expanded graphite sheet and a metal plate of a specific shape can withstand even higher pressure and higher temperatures than the previous gasket, and is strongly bonded and has extreme resistance. This invention was completed based on the knowledge that the laminated layers do not peel off due to pressure fluctuations and that the work environment is good for manufacturing.

[Structure of the idea]

The gist of the present invention is that in a gasket formed by laminating and bonding a plurality of flexible graphite sheets and metal plates alternately, the outer diameter of the metal plates forming the top and bottom layers of the gasket is The diameter of the central hole of the metal plate forming the uppermost layer and the lowermost layer is larger than the outer diameter of the thin metal plate other than the plate, and the diameter of the central hole of the metal plate forming the uppermost layer and the lowermost layer is smaller than the diameter of the central hole of the metal plate other than the said metal plate, and the uppermost layer and the lowermost layer The metal plate has a skirt portion bent in the longitudinal direction of the gasket on its outer and inner periphery, and the total length of the skirt portion of the metal plate in the axial direction of the gasket is smaller than the axial length of the gasket. This is a gasket.

Flexible graphite sheets are produced by pressure molding expandable graphite in the absence of adhesives, by adding boric acid or borate to graphite treated with an oxidizing agent, or by using other inorganic adhesives or thermal oxidation. It can be obtained by adding a rubber resin, then heating to convert it into expanded graphite, melting and coating the expanded graphite with boric acid or a borate, and press-molding the obtained expanded graphite.

In order to alternately laminate and bond flexible graphite sheets and metal plates, the flexible graphite sheets are press-molded into the desired shape, and this molded body is laminated alternately with the metal plates and bonded under pressure. Alternatively, a method of bonding with an adhesive may be adopted. Although not particularly limited to metal plates,
Iron, copper, aluminum, etc. are used, and a stainless steel plate is preferable.

〔Example〕

The present invention will be described below with reference to embodiments.

FIG. 1 is a diagram showing one embodiment of the present invention, which is an annular or elliptical body.

In the figure, 1a, 1b, and 1c are metal plates, preferably stainless steel thin plates.

A flexible graphite sheet 2 is inserted and laminated between each thin metal plate.

A suitable adhesive is interposed between the flexible graphite sheet 2 and the metal plate to bond them together.

Note that it is also possible to bond such a laminate without using an adhesive by applying considerable pressure from above and below, for example, about 10 kg/cm ² .

In this case, at least one intermediate metal plate 1c is interposed between the upper metal plate 1a and the lower metal plate 1b, and a graphite sheet 2 is interposed between these metal plates 1a, 1b, and 1c.

The intermediate metal plate 1c has an outer diameter smaller than the upper or lower metal plates 1a or 1b, and an inner diameter larger than these inner diameters.

In this way, there will be some gaps between the flexible graphite sheets at both the inner and outer peripheral edges in a simple laminated state, but if an appropriate pressure is applied between the uppermost metal plate 1a and the lowermost metal plate, At the same time as this gap was closed, both flexible graphite sheets were adhered to each other, resulting in a complete gasket.

The uppermost and lowermost metal plates 1a and 1b are
This ring has a U-shaped cross section and has a flat portion 3 and skirt portions 4a and 4b. In the figure, the length of the skirt 4a is shown to be longer than that of the skirt 4b, but they may be the same.

However, it goes without saying that the sum of the height of the longer skirt and the height of the opposing metal plate 1b must be smaller than the height (thickness) of the gasket.

The advantage of using such metal plates 1a and 1b is that a stronger structure can be achieved and greater strength can be expected.

To make such a gasket, ring-shaped metal plates and ring-shaped graphite sheets may be alternately laminated, for example, by press working.

Alternatively, metal webs and graphite sheets may be alternately laminated and bonded, and the resulting laminated sheet may be formed into a ring shape by press working.

The gasket obtained in this way was heated to a maximum temperature of 400°C.
It was used as a gasket for the suction and discharge valves of a plunger pump used to transfer heavy oil with a viscosity of 3800 cp (centipoise), and after approximately 3 months of continuous use, it was disassembled and investigated, but no abnormalities were found.

In the above embodiment, metal plates 1a, 1b, 1c
Both were explained as having no holes or the like.

In practice, both 1a and 1b may be square, but 1c does not necessarily need to be so, and may be a plate material with appropriate holes or a metal mesh.

[Effect of idea]

According to the present invention, since a flexible graphite sheet is used to make the graphite gasket, the generation of graphite powder is extremely small.

In addition, the gasket of the present invention is made of a flexible graphite sheet and a metal plate of a specific shape, which are interlaced, laminated, and bonded together, so it is extremely solid and strong, and does not leak even when liquid is pumped under high temperature and high pressure. There's nothing to do.

Since the gasket of the present invention simply consists of alternately laminating and bonding flexible graphite sheets and metal plates, the process is simple and quality control is easy.

In addition, with the configuration of the present invention, even if multiple expanded graphite sheets and metal plates are laminated, the flexible graphite sheets can be easily and firmly adhered to each other in areas where there are no metal plates, so that severe pressure fluctuations can be avoided. The laminated layers do not peel off, and by providing metal plates on the top and bottom layers and providing a skirt,
It has a stronger structure, has greater restoring force as a gasket, has improved interlaminar strength, and can withstand severe pressure fluctuations.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional view of a gasket according to an embodiment of the present invention. In the figure, 1a is the top metal plate, 1b is the bottom metal plate, 1c is the middle metal plate, 2 is a flexible graphite sheet,
4a and 4b indicate the skirt portions of the uppermost (lower) metal plate, respectively.

Claims (1)

[Scope of claims for utility model registration] (1) In a gasket made by laminating and bonding a plurality of flexible graphite sheets and metal plates alternately,
The outer diameter of the metal plates forming the uppermost layer and the lowermost layer of the gasket is larger than the outer diameter of the thin metal plates other than the above metal plate, and the diameter of the central hole of the metal plate forming the uppermost layer and the lowermost layer is larger than the outer diameter of the metal plate forming the uppermost layer and the lowermost layer. smaller than the diameter of the central hole of the metal plate other than the plate, the uppermost and lowermost metal plates have skirt parts bent in the longitudinal direction of the gasket on their outer and inner peripheries, and the skirt of the metal plate A gasket in which the total axial length of the gasket is smaller than the axial length of the gasket. (2) The gasket according to claim 1, wherein the gasket has a ring-like shape having a substantially circular outer periphery and a substantially circular inner periphery. (3) The gasket according to claim 1, wherein at least one of the metal plates is a metal mesh. (4) The gasket according to claim 1 of the utility model registration, characterized in that the gasket is formed by laminating a metal plate and a flexible graphite sheet and pressurizing them. (5) The gasket according to claim 1 of the utility model registration, characterized in that the gasket is formed by interposing an adhesive between a metal plate and a flexible graphite sheet.