JP2001193878A - Fuel cell insulation joint and assembly method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an insulated joint which facilitates degreasing of an insulating gasket and a method of assembling the same. SOLUTION: A first flange 12, a second flange 13 arranged at a distance from the first flange 12, and a first flange 12 are provided between the first flange 12 and the second flange 13, and the first flange 12 is provided at one end. A short pipe 14 having a first side flange 15 which engages with the flange 12 and a second side flange 16 which engages with the second flange 13 at the other end, and an intermediate portion provided between the second flange 13 and the second side flange 16 Flange 17
An insulating gasket 18 provided between the intermediate flange 17 and the second side flange 16;
, The intermediate flange 17 and the second side flange 16, and a tightening bolt 20 insulated from the second side flange 16.
And.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an insulating joint used for a fuel cell and a method for assembling the same.

[0002]

2. Description of the Related Art Insulating joints such as fuel cell pipes have a structure in which an insulating gasket is sandwiched between flanges to be joined and tightened with tightening bolts. FIG. 5 shows an example of such an insulated joint. Each of the pipes 1a and 1b has a flange 2
a, 2b are provided, an insulating gasket 4 is inserted between the flanges 2a, 2b, and tightened with tightening bolts 3. The tightening bolt 3 is insulated by an insulating member. Usually, as shown in the figure, an insulating ring 5 for preventing contact between the flange 2b and the tightening bolt 3 is fitted.
An insulating washer 6 is provided for preventing contact with the insulating washer.
With this structure, insulation and sealing properties are maintained.

[0003]

The insulating joint of the fuel cell is exposed to a high temperature, for example, about 700.degree. For this reason, a ceramic fiber sheet gasket is used for the insulating gasket in consideration of electric sealing properties, gas sealing properties, and heat resistance. An organic binder is used for this gasket as it has workability during shape processing and conformability to a contact surface during initial tightening. If there is not enough oxygen inside the piping where the insulating gasket is provided and in the atmosphere around the piping when the temperature of the fuel cell is raised, the carbon content of the organic binder in the insulating gasket component will be. Residual and carbonized, the electrical insulation is significantly reduced. Therefore, when the temperature is raised for the first time after the installation of the battery, the gasket needs to be degreased (remaining carbon is gasified into carbon dioxide or the like and removed).
Therefore, conventionally, when the temperature is raised for the first time after the installation of the battery, air has been flowed through the pipe until the degreasing is completed. When the insulation joint is near the battery and the battery is covered with a pressurized container, the inside of the container is usually set to a nitrogen atmosphere, but it is necessary to flow air into the container until the end of degreasing, and an air line is provided. Was. As described above, it takes considerable equipment cost, labor and time to raise the temperature inside and outside the pipe having the insulating joint by setting the air atmosphere.

[0004] The present invention has been made in view of the above problems, and has as its object to provide an insulated joint and a method of assembling the same in which the insulating gasket can be easily degreased.

[0005]

In order to achieve the above object, according to the first aspect of the present invention, there is provided a first flange, a second flange spaced from the first flange, and a first flange. A short pipe provided between the second flange and having at one end a first side flange engaging with the first flange and at the other end having a second side flange engaging with the second flange;
An intermediate flange provided between the second flange and the second side flange, an insulating gasket provided between the intermediate flange and the second side flange, and a second flange, an intermediate flange, and a second side flange tightened. A fastening bolt insulated from the second side flange.

[0006] With this configuration, it is possible to tighten the insulating gasket between the second side flange and the intermediate flange of the short pipe with a bolt and heat the same in an air atmosphere to degrease it. While maintaining the tightened state, the second flange, the intermediate flange, and the second side flange are tightened with tightening bolts. Also, the first side flange and the first flange of the short pipe are joined. Since the insulating joint can be formed between the first flange and the second flange after degreasing the insulating gasket in this manner, degreasing at the time of the first temperature rise after battery installation is not required.

According to a second aspect of the present invention, a first flange is provided at one end between the first flange and a second flange disposed at a distance from the first flange, the first flange being engaged with the first flange. A short pipe having a second side flange engaging with the second flange is provided, an intermediate flange is provided between the second flange and the second side flange, and an insulating gasket is provided between the intermediate flange and the second side flange. The method for assembling an insulating joint for a fuel cell, wherein the second flange, the intermediate flange, and the second side flange are tightened with tightening bolts, wherein the intermediate flange, the insulating gasket, and the second side flange are tightened with tightening bolts. The short pipe is heated in an air atmosphere to degrease the insulating gasket. After the degrease processing, the tightening state is maintained with the temporary bolts, and the tightening bolts are removed. After tightening the intermediate flange and the insulating gasket and the clamping bolt a second side flange, so that removing the temporary bolts.

After the intermediate flange, the insulating gasket, and the second side flange are tightened with the tightening bolts, the short pipe to which the flanges are attached is heated in an air atmosphere to perform a degreasing process on the insulating gasket. After performing this degreasing treatment, the tightening state is maintained by the temporary bolts, and the tightening bolts are removed. The second flange, the intermediate flange, the insulating gasket, and the second side flange are tightened by the tightening bolts, and then the temporary bolts are removed. Thereafter, the first side flange and the first flange are connected. As described above, since the first flange and the second flange are degreased before being connected via the short pipe and the intermediate flange, the degreasing at the time of the first temperature increase after the battery is installed is unnecessary. The insulating gasket is sandwiched between flanges and tightened with bolts to degrease it. The second flange, intermediate flange, insulating gasket and second side flange are joined together with tightening bolts without loosening. When the material is used as it is, it loses conformability to the flange surface and cracks occur due to thermal stress at the time of flange tightening and temperature rise. This is because it cannot be held.

[0009]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows a configuration of an embodiment of the present invention. The first pipe 10 having the first flange 12 and the second pipe 11 having the second flange 13 are connected via the short pipe 14 and the intermediate flange 17. On the first flange 12 side of the short pipe 14, a first side flange 15 is provided.
A second side flange 16 is provided on the flange 13 side. The pipes 10, 11, the short pipe 14, and the flanges 12, 13, 15, 16, 17 are made of metal.

The first flange 12 of the first pipe 10 and the short pipe 1
4, the metal gasket 19 is sandwiched between the first side flanges 15 and the sealing performance is maintained by tightening the bolts 26 and the nuts 27. The second side flange 16 of the short pipe 14 and the second pipe 1
1, an intermediate flange 17 is provided between the second flange 13 and the second side flange 16 and the intermediate flange 1.
7, an insulating gasket 18 is sandwiched between
And a metal gasket 19 between the second flange 13 and
Tighten with the tightening bolt 20. An insulating ring 22 is fitted to the tightening bolt, and insulating washers 23 and 24 are sandwiched between the nut 21 and the second side flange 16. 25 is a metal washer.

FIG. 2 shows a cross section taken along line XX of FIG. The intermediate flange 17 is provided with a tightening bolt hole 28 and a temporary bolt screw hole 29 on the same pitch circle as the bolt hole 28. A hole for a fastening bolt and a hole for a temporary bolt are also provided at positions corresponding to the second side flange 16.

With such a configuration, the metal gasket 19 maintains the sealing property between the second flange 13 and the intermediate flange 17, and the intermediate flange 17 and the second side flange 16
The sealability and the electrical insulation are maintained by the insulating gasket 18, the insulating ring 22, and the insulating washers 23 and 24. A stepped portion 30 is formed on the second side flange 16, and a gap is formed between the second side flange 16 and the insulating gasket 18. When the second side flange 16 is tightened by the tightening bolt 20, the second side flange 16 is bent. This thermal expansion is absorbed by the flexure to prevent the tightening force of the bolt 20 from decreasing.

The insulating gasket 18 is a sheet-shaped gasket made of ceramic fiber containing alumina fiber as a main component. The gasket has an organic bonding to improve workability at the time of shape processing and conformity to a contact surface at the time of initial tightening. Wood is used. When the organic binder is first heated to a high temperature (about 700 ° C., which is the operating temperature of the fuel cell),
If there is not enough oxygen, carbon remains and carbonizes, resulting in a significant decrease in electrical insulation. Therefore, it is necessary to perform degreasing by heating in an air atmosphere to gasify carbon into carbon dioxide gas and remove it. When this degreasing is performed with the gasket alone,
The loss of the binder causes loss of flexibility and embrittlement. When this gasket is used, the conformability to the flange surface is reduced, and cracks occur due to thermal stress at the time of tightening the flange and increasing the temperature, so that the gas sealing property cannot be secured. For this reason, in the past, degreasing was performed after a pipe having an insulating joint was installed in the fuel cell. However, as described above, there is a problem in air supply. Therefore, in the present invention, the insulating joint has the structure shown in FIG. Perform degreasing and installation by the method described in (1).

FIGS. 3 and 4 are views showing a method of installing an insulating joint of a pipe. FIG. 3A shows the short pipe 14 and the intermediate flange 1.
FIG. 3 is a component assembly view before the 7 and the insulating gasket 18 are tightened with the tightening bolts 20. An insulating gasket 18 is sandwiched between the second side flange 16 and the intermediate flange 17 of the short pipe 14, an insulating ring 22 is fitted into a bolt hole, and a tightening bolt 20 is inserted.
Through the insulating ring 22 and the nut 21 through the insulating washers 23 and 24 with a specified torque. One or more insulating gaskets may be used. During the assembly, an insulating ring and an insulating washer are used because the second side flange 16 and the intermediate flange 17 of the short pipe 14 are used.
Is electrically insulated, and the conductor is drawn out of the furnace from both flanges, thereby making it possible to measure the insulation resistance during and after degreasing. As a result, it can be confirmed that the electrical insulation has not been reduced due to poor degreasing or the like.
When only the purpose of degreasing the gasket is intended, the insulating ring and the insulating washer may not be provided.

FIG. 3B shows a state in which the insulating gasket 18 incorporated in the short pipe 14 is heated and degreased in a small furnace.
The inside of the furnace is air atmosphere, and the heating temperature and time are 350
30 ° C. + 550 ° C. for about 12 hours. These are merely examples, and are determined by the decomposition temperature of the organic binder contained in the insulating gasket and the like. Since the degreased insulating gasket is brittle due to the loss of the binder, after cooling in a furnace to near normal temperature to prevent cracking due to thermal shock,
Take out. Here, if a closing flange provided with a rubber packing and a gas supply pipe is attached to the first side flange 15 and the intermediate flange 17 of the short pipe 14, respectively, the gas leak amount can be measured. By enabling measurement of insulation resistance during and after degreasing and measurement of gas leakage after degreasing, it can be installed on site after confirming the soundness of electrical insulation and gas seals. It is valid.

FIG. 3C shows a state in which the temporary bolt 31 holds the intermediate flange 17 after degreasing, and then the tightening bolt 20 is removed. The temporary bolt 31 may have a different diameter from the fastening bolt 20. If the diameter of the temporary bolt 31 is reduced, interference with the tightening bolt 20 can be prevented, and a decrease in flange strength due to the addition of a bolt hole or a screw can be minimized. When the diameter of the temporary bolt 31 is reduced, the tightening force is smaller than the state where the temporary bolt 31 is tightened by the tightening bolt 20. However, the state in which the temporary bolts 31 are tightened is a temporary state such as when the bolts are changed from the degreased state to the installed state and when the bolts are transported during the period, and there is no problem because gas sealing properties are not expected.

FIG. 4A shows a state in which the intermediate flange 17 and the insulating gasket 18 are fastened to the short pipe 14 with temporary bolts 31. Usually in this state, it is sent from the factory to the installation site.

FIG. 4B shows a short pipe 14 at the installation site.
5 shows a state in which the second pipe 11 is connected to the second pipe 11. Metal gasket 1 between intermediate flange 17 and second flange 13
9, the insulating ring 22 is fitted in the bolt hole, passed through the insulating washers 23 and 24, and tightened with the tightening bolt 20 to a specified torque.

FIG. 4C shows a state where the short pipe 14 and the second pipe 11 are connected with the fastening bolts 20 and then the temporary bolts 31 are removed. As a result, the insulating gasket 18 is tightened in the same state from when it was first mounted between the intermediate flange 17 and the second side flange 16 until the connection with the piping is completed, and thereafter, so that it fits into the flanges 16 and 17. , Cracks and the like are prevented, and insulation and sealing properties can be maintained.

FIG. 4D shows the short pipe 1 connected to the second pipe 11.
4 shows a state in which it is connected to the first pipe 10. First pipe 10
The metal gasket 19 is interposed between the first flange 12 of the short pipe 14 and the first side flange 15 of the short pipe 14, and the bolt 26 and the nut 2
7 secures the sealing performance.

In the above-described embodiment, the connection joint of the pipe has been described. However, the present invention can be applied to any joint connected by a flange. For example, the first pipe may be a nozzle, and the second pipe may be a header or the like.

[0022]

As apparent from the above description, the present invention has the following effects. 1) By using the short pipe and the intermediate flange, degreasing can be performed in a small furnace or the like with the insulating gasket fastened between the flanges, so that the degreasing operation is facilitated and the need for degreasing at the time of battery temperature rise after pipe installation is eliminated. 2) By using temporary bolts, it is possible to maintain the tightening force of the insulating gasket from degreasing to the time of installation of the pipe, so that the insulating gasket can maintain a state of being fitted to the flange, and cracking due to retightening can be prevented.
Gas sealability can be secured. 3) Measurement of insulation resistance during and after degreasing and measurement of gas leak after degreasing are completed, so that it can be installed on site after confirming the soundness of electrical insulation and gas seals, and quality control. Is effective.

[Brief description of the drawings]

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

FIG. 2 is a sectional view taken along line XX of FIG.

FIG. 3 is a view for explaining a pipe joint assembling method of the present invention.

FIG. 4 is a diagram illustrating a method of assembling a pipe joint according to the present invention.

FIG. 5 is a view showing a conventional pipe joint.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 1st piping 11 2nd piping 12 1st flange 13 2nd flange 14 Short pipe 15 1st side flange 16 2nd side flange 17 Intermediate flange 18 Insulation gasket 19 Metal gasket 20 Tightening bolt 22 Insulation ring 23,24 Insulation washer 30 Step 31 Temporary bolt

Continuation of the front page (72) Inventor Mitsuo Otsubo 3-1-1-15 Toyosu, Koto-ku, Tokyo Ishikawajima Harima Heavy Industries, Ltd. Tokyo Engineering Center F term (reference) 3H016 AE00 FA04 5H027 AA05

Claims (2)

[Claims] 1. A first flange, a second flange disposed at a distance from the first flange, and a second flange provided between the first flange and the second flange and having one end engaged with the first flange. A short pipe having a first flange and a second flange at the other end engaging with the second flange, an intermediate flange provided between the second flange and the second flange, and the intermediate flange and the second flange; And an insulating gasket provided between the first and second flanges, and a tightening bolt for tightening the second flange, the intermediate flange, and the second side flange and insulated from the second side flange. Fittings. 2. A first flange at one end between a first flange and a second flange spaced from the first flange.
A short pipe having a first side flange engaging with the flange and having a second side flange engaging with the second flange at the other end;
An intermediate flange is provided between the second flange and the second side flange, an insulating gasket is provided between the intermediate flange and the second side flange, and the second flange, the intermediate flange, and the second
In the method for assembling an insulating joint for a fuel cell, wherein the side flange is tightened with a tightening bolt, the intermediate pipe, the insulating gasket and the second side flange are tightened with a tightening bolt, and then the short pipe is heated in an air atmosphere. After degreasing the insulating gasket, remove the tightening bolts while maintaining the tightening state with temporary bolts after degreasing, and tighten the second flange, intermediate flange, insulating gasket, and second side flange with tightening bolts, and then tighten temporary bolts. A method for assembling an insulating joint for a fuel cell, comprising: