JPH086855B2 - High temperature insulation fitting - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pipe joint having a gas seal function, and more particularly to a pipe joint having a gas seal function having good electric insulation at high temperatures.

[0002]

2. Description of the Related Art For example, as a joint structure of a gas pipe of a fuel cell, which has a gas sealing function and is required to have an electrical insulating property in a high temperature environment, an annular structure is provided between pipe flanges arranged opposite to each other. An electrically insulating ceramic member and a gas seal material are provided side by side, and are tightened and coupled by an insulating bolt and a nut, and a metal O-ring is used as a gas seal material at the joint portion (Japanese Patent Laid-Open No. 56-56). 461
No. 90) or a gas sealant thereof using a substance having a melting point lower than the joint use temperature and a boiling point higher than the joint use temperature (JP-A-1-255785).

However, in the former structure, the problem that the ceramic member is broken during the heat cycle due to the tightening force of the flange, the gas leak due to the difference in thermal expansion of each member made of a metal material, and the damage of each constituent member. Therefore, great care must be taken when tightening the flange, and the structure is complicated and the number of parts is large, so that assembly is difficult, resulting in high cost.

Further, in the latter structure, by adopting a wet seal structure using a metal material having specific physical properties, the tightening force can be reduced, and the problems such as breakage of constituent members can be solved. Since this seal structure utilizes the surface tension of the liquid, there is no choice but to put a certain limit on the gas pressure environment used.

[0005]

The above-mentioned prior art has a structure in which the opposing flanges are tightened and coupled by insulating bolts and nuts, so that in both cases, the two piping members are mutually constrained and the degree of freedom is reduced. There is no. Therefore, it is difficult to completely avoid the gas leakage due to the destruction of members due to the difference in thermal expansion of each constituent member at high temperature and the thermal deformation,
In addition, there is a possibility that a seal breakage phenomenon may occur due to damage of the ceramic member due to heat cycle or the occurrence of unexpectedly high pressure, and the sealing performance may be deteriorated. Further, all of them have problems such as difficulty in assembling due to complicated structure and high cost.

Therefore, an object of the present invention is to obtain an insulating joint for high temperature which solves the above problems. Another object of the present invention is to obtain a high temperature insulating joint in which the sealing member is not damaged by the tightening force of the flange. Still another object of the present invention is to obtain a high-temperature insulating joint in which destruction of a member due to a difference in thermal expansion and gas leakage due to thermal deformation are completely prevented by eliminating a fastening means between two piping members. . Still another object of the present invention is to obtain a high temperature insulating joint whose sealing performance is not affected by gas pressure. Still another object of the present invention is to obtain an insulating joint for high temperature which has a simple structure and is inexpensive.

[0007]

In order to achieve the above object, the present invention provides a heat-resistant and insulative substance that is held in close contact with the circumference of one of the opposing piping members while the other An insulating joint for high temperature in which an end of a piping member is embedded, wherein the substance having heat resistance and insulation has physical properties such that the melting point is lower than the operating temperature of the joint and the boiling point exceeds the operating temperature of the coupling. Disclosed and provided is an insulating joint for high temperature, which is characterized by being a substance.

Examples of such a heat-resistant insulating substance include a mixture of a glassy substance and a heat-resistant insulating ceramic powder. Specific examples thereof include a powdery glassy substance. Mixture with heat resistant insulating ceramic powder, such as borosilicate glass, B ₂ O ₃ -PbO based solder glass or heat resistant insulating ceramics with them
It is particularly effective to use a mixture of (Al ₂ O ₃ etc.) powders. Furthermore, the greater the specific gravity of the substance to be enclosed, the longer the length of the substance to be enclosed in the pipe direction and the deeper the end of the other pipe member is, the greater the sealing effect will be.

[0009]

The insulating joint for high temperature according to the present invention is constructed by embedding the end portion of the other piping member in a heat-resistant insulating material that is closely adhered to the periphery of one piping member facing the other gas member. Because of the sealing structure, the tightening mechanism such as the conventional flange type joint is not required, and the assembly is simplified. Also, since the opposing piping members are not constrained to each other, stress does not occur even if the constituent members are deformed by heat, gas leaks due to destruction of the constituent members, etc. can be avoided, and the same applies to the heat cycle. The sealing performance does not deteriorate.

Furthermore, since the sealing function does not utilize the surface tension of the liquid, it can sufficiently fulfill the sealing function against a high-pressure gas flow.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIG. The high temperature insulating joint according to the present invention basically comprises a cylindrical member 1a formed at a tip portion of one of the pipe members 1 facing each other, a gas sealing material 3 enclosed in the cylindrical member 1a,
And the other pipe member 2 facing each other, at least its tip portion 2a has a diameter larger than the outer diameter of the cylindrical member 1, and at least the tip portion of its large diameter portion has the cylindrical member 1a.
It is composed of the piping member 2 embedded therein.

That is, one of the two piping members 1 and 2 facing each other, in this embodiment, a cylinder 1a having a bottom at the tip of the piping member 1 is formed by integral molding or brazing. Then, the cylinder 1a is filled with a gas sealing material 3 described later. Further, two inner and outer annular insulating members 4a and 4b made of an electrically insulating material, for example, an alumina-based ceramic, are attached to the opening of the tip of the cylinder 1a with a constant gap d.

At least the tip portion 2a of the other piping member 2 facing the piping member 1 is formed into a large diameter portion having an inner diameter larger than the outer diameter of the piping member 1, and the large diameter portion is the inner or outer portion. It passes through a gap d between the two annular members 4a and 4b and enters the cylinder 1a. Further, a flange 2b is formed at a certain distance inward from the tip of the large diameter portion of the pipe member 2, and the flange 2b regulates the distance of entry of the pipe member 2 into the cylinder 1a. Obviously, the entire pipe member 2 may be a pipe member having an inner diameter larger than the outer diameter of the pipe member 1.

This insulating joint is assembled as follows. First, in a state where the pipe member 1 is vertically supported by an appropriate support member (not shown), a substance that is powdery at room temperature but softens and liquefies at high temperature, such as the above-mentioned borosilicate, is placed in the cylinder 1a. A gas sealing material made of acid glass, B ₂ O ₃ -PbO-based solder glass, or a mixture thereof with a powder of heat-resistant insulating ceramics (Al ₂ O ₃ etc.) is filled. After filling, an annular electrical insulating member 4a made of an annular ceramic material,
4b is attached to the tip opening. At that time, the diameter and width of the gap d formed by the two annular electrical insulating members 4a and 4b are designed in advance so that the large diameter portion 2a of the other opposing piping member 2 can enter. To do. After that, the large diameter portion 2a of the other piping member 2 is embedded in the cylinder 1a through the gap d, whereby the assembly of this insulating joint is completed.

When this insulating joint is used, for example, in the gas flow path of a molten carbonate fuel cell, the insulating joint gradually rises in temperature, and the normal operating temperature is 650 ° C to 700 ° C. Cylinder 1a
When borosilicate glass is used as the substance 3 to be filled in as a gas sealant, it softens and becomes liquid at 350 ° C. to 470 ° C., so the gas sealant becomes liquid glass at the above-mentioned use temperature, Performs a sufficient sealing function. In addition, the insulating annular member interposed between the two piping members maintains a required creepage distance there and is electrically insulated.

Since this joint does not utilize the surface tension of the liquid as a sealing function, it can seal up to a sufficiently high pressure, and its sealing performance is the specific gravity of the substance to be filled as the sealing material and the length of the filling portion in the piping direction. The effect is greater as the specific gravity of the substance is larger and the length of the filling portion is longer. They may be appropriately selected according to the usage environment.

Furthermore, since the joints are not fastened with bolts or the like between the pipe members, both of them have a high degree of freedom, and therefore the creepage distance between the pipe member 1 and the pipe member 2 used for the joint is maintained. The sizes of the alumina-based annular ceramics 4a and 4b and the piping members 1 and 2 are set so that stress does not occur even if thermal expansion occurs in both members at the operating temperature. It does not occur and it becomes easy to prevent the destruction of the constituent members.

[0018]

EFFECTS OF THE INVENTION According to the present invention, the structure in which the liquid is gas-sealed eliminates the need for a complicated tightening mechanism, which causes stress due to the difference in thermal expansion of the constituent members, causing the members to be destroyed or the members to be thermally deformed. No more worrying about gas leaks. Further, since each constituent member is not constrained, the influence of deformation due to heat is small, so that it has an excellent effect on the heat cycle.

Further, there is an effect that the structure is simplified, difficulty in assembling is eliminated, and cost is also advantageous.

[Brief description of drawings]

FIG. 1 is a diagram showing a cross section of an embodiment of the present invention.

[Explanation of symbols]

1 ... Piping member 4a ... Annular ceramic member 1a ... Cylindrical 4b ... Annular ceramic member 2b ... Flange 2 ... Piping member 2a ... Large diameter part at tip 3 ... Gas sealing material

Front page continuation (72) Inventor Tsutomu Takahashi 3-1-1, Saiwaicho, Hitachi City, Ibaraki Hitachi Ltd. Hitachi factory (72) Inventor Tadashi Takashima 3-1-1, Saiwaicho, Hitachi City, Ibaraki Prefecture Stock company Hitachi Ltd. Hitachi factory (56) Reference JP-A-1-18318 (JP, A) JP-B-63-46315 (JP, B2)

Claims (2)

[Claims] 1. A high-temperature insulating joint obtained by embedding an end portion of the other piping member in a substance having heat resistance and insulating properties which is held in close contact with the periphery of one of the facing piping members.
The substance that has heat resistance and insulation is
Is below the operating temperature of the joint, and the boiling point
Insulated joint for high temperature, which is a substance with physical properties that exceed . 2. A material having a heat resistant and insulating properties, characterized in that it is constituted of a mixture of glassy material and heat insulating ceramic powder, according to claim 1 for high temperature insulation joint according.