JPH0663994U - Connection tube for fuel cell - Google Patents

Abstract

(57) [Abstract] [Purpose] To provide a connecting pipe that can be used for a cooling system or a fuel system in a fuel cell. [Structure] A tubular joint member 3 made of a fluororesin having at one end a connecting portion 3b for a pipe to be connected in a fuel cell such as a pipe or a screw, and a tubular body 2 made of a fluororesin at the other end. Heat seal to the edges. [Effect] The sealing property of the connecting portion is improved, the sealing property is not changed even in the thermal cycle, and the manufacturing cost can be reduced.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a connecting pipe used in a fuel cell that generates electricity by electrochemically reacting hydrogen obtained from a fuel such as natural gas, methanol, or coal with oxygen in the atmosphere.

[0002]

[Prior art]

 Although various fuel cells have been developed in recent years, the first-generation phosphoric acid fuel cells are the closest to practical use. A phosphoric acid fuel cell is a type that uses a concentrated aqueous solution of phosphoric acid as an electrolyte, and typically has a single cell in which a matrix impregnated with an electrolytic solution is sandwiched between a fuel electrode (anode) and an air electrode (cathode). It has a structure in which hundreds of layers are stacked through a separator plate. In this type of fuel cell, it is used as piping material for the reaction gas system that guides the fuel gas and air for oxidation to each cell, and the cooling system that supplies the refrigerant to the cooler installed between the cells to cool the cells. Insulating connecting pipes such as tubes, hoses, etc. are used. The electrochemical reaction in the fuel cell is an exothermic reaction, and the reaction is likely to proceed when the operating temperature or the operating pressure is raised. Therefore, the fuel cell is usually operated at 180 to 220 ° C. Furthermore, in the pressure vessel that houses the cells, phosphoric acid, which is the electrolyte, is atomized and scattered during operation along with the exhaust gas, so the connection pipe has excellent heat resistance in addition to electrical insulation. Corrosion resistance is required. Conventional examples of connecting pipes used for such purposes include those described in JP-A-62-62081 and JP-A-1-149372.

[0003]

[Problems to be solved by the device]

 However, for connection with a pipe to be connected in the fuel cell, such as a cooling water supply branch pipe in a cooling system, for example, a joint consisting of a core metal pipe and a metal caulking pipe is connected to the terminal pipe. In this case, not only the cost of the joint to be used is high, but also it takes time to mount the joint, which causes a drawback that the manufacturing cost of the entire connecting pipe increases. Also, in the case of a connection pipe that is crimp-fixed by tightening the pipe body of the insertion part with a band from the outside in the state that the pipe body is inserted into the pipe to be connected, the inner peripheral surface of the band does not necessarily become a perfect circle. Therefore, there is a drawback that a gap is generated between the pipe body and the insertion portion of the pipe to be connected, and water is likely to leak from the connection portion. Furthermore, in any of the connecting pipes, fluorocarbon resin is used for the pipes, and since these pipes are attached to the pipes to be connected while being compressed from the outer circumference by caulking pipes or bands, they are installed at room temperature to 200 ° C. The creep phenomenon is likely to occur in the fluororesin during the heat cycle up to, and as a result, the tightening force due to the caulking tube or band added at the initial stage of assembly is weakened and the sealing performance is extremely deteriorated.

The present invention has been made in view of the above problems of the prior art, and provides a connecting pipe for a fuel cell, which has a good sealing property, excellent durability, and can be manufactured at low cost. To aim.

[0005]

[Means for Solving the Problems]

 In order to achieve the above object, the connecting pipe for a fuel cell according to the present invention comprises a tubular joint member made of a fluororesin having a connecting portion for a pipe to be connected in the fuel cell at one end and a fluororesin at the other end. It is characterized in that it is heat-sealed to the end of the tube.

In this configuration, the fluorocarbon resin that is the material of the tubular body and the joint member is tetrafluoroethylene resin, tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer resin, tetrafluoroethylene-hexafluoride. Examples thereof include propylene-perfluoroalkyl vinyl ether terpolymer resin, tetrafluoroethylene-hexafluoropropylene copolymer resin, and trifluoroethylene chloride resin. Further, for the purpose of improving the mechanical strength of these fluorine-based resins, it is possible to mix various fillers to the extent that their corrosion resistance is not impaired.

Further, the shape of the connecting portion provided at one end of the joint member is appropriately selected according to the shape of the connecting portion of the connected pipe to be connected, such as a male screw shape, a female screw shape, and a pipe shape. The other end of the joint member used for fusion-bonding with the pipe body is preferably formed into a pipe shape having a diameter that is externally or internally fitted to the pipe body to be joined, but this is not always the case. Not limited to. Then, the joint member and the pipe body are heat-sealed in, for example, air or a liquid heated above the melting point of the fluororesin.

[0008]

[Action]

 In the present invention, both the joint member and the tubular body are made of a fluorine-based resin having excellent heat resistance and corrosion resistance, so that the joint member and the pipe body can sufficiently withstand use in a fuel cell. And since they are joined by heat fusion, the airtightness of the joined part is improved as compared with the conventional connecting pipe in which a caulking pipe is joined to the end part of the pipe body as a means for connecting to the pipe to be connected. Reliability is greatly improved. Furthermore, since the pipe body is joined to the joint member without being clamped from the outside unlike the conventional connecting pipe using a caulking pipe or a band, the creep phenomenon does not occur on the pipe wall made of fluororesin. Therefore, the sealing property does not change even in the thermal cycle from room temperature to 200 ° C, and the durability is improved. Further, the joint member is tubular and can be manufactured at low cost by injection molding or the like, and is easily joined to the pipe body by heat fusion, so that the manufacturing cost of the connecting pipe is reduced.

[0009]

【Example】

 Next, the connecting pipe for a fuel cell according to the present invention will be described with reference to the accompanying drawings, but of course the present invention is not limited to the embodiments, and modifications within the technical concept of the present invention are possible. 1 and 2 are front views showing a different embodiment of a connecting pipe for a fuel cell according to the present invention with a part of an end portion cut away.

A connecting tube 1 for a fuel cell shown in FIG. 1 is a cylindrical joint with a collar made of tetrafluoroethylene resin at an end of a tube body 2 made of tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer resin. The member 3 is combined. In FIG. 1, the joint member 3 has a pipe-shaped portion 3b on one end side of the central flange portion 3a, and this portion 3b is a connecting portion for connecting to a connected pipe in a fuel cell. Has become. Further, the other end side portion 3c is formed in a pipe shape having an outer diameter adapted to the inner diameter of the pipe body 2 to be connected, and is joined by heat fusion in a state fitted in the end portion of the pipe body 2. . In this case, the connection between the fuel cell connecting pipe 1 and the connected pipe in the fuel cell is performed by inserting the sleeve into the outer peripheral surface of the pipe such as JIS B 2351 “Hydraulic pipe fitting”. By interposing a pipe joint of this type between them, inserting the connecting portion 3b of the joint member 3 into the pipe joint, and tightening the union nut of the pipe joint, a simple and reliable connection can be achieved. When the thickness of the connecting portion 3b of the joint member 3 is not sufficient, it is convenient to insert a metal tubular body inside.

When the connecting portion 3b of the joint member 3 has a pipe shape as in the above embodiment, for example, a large number of fuel cells are provided in a cooling water supply branch pipe or a cooling water discharge junction pipe in the fuel cell. When connecting the connection pipes for fuel cells in parallel, even if the finished length of the connection pipes for the fuel cell varies, it is possible to handle it by adjusting the length to be inserted into the pipe joint of the connecting portion 3b. .

In addition, in the fuel cell connecting pipe 10 shown in FIG. 2, the joint member 11 is provided with a hexagonal nut-shaped spanner hooking portion 11a in the central portion, and the one end side portion 11b of the joint member 11 is formed in a male screw shape. This is the connecting part for the connected pipe in the fuel cell. The other end side portion 11c is formed in the same pipe shape as in the above-mentioned embodiment, and is joined to the pipe body 12 by heat fusion.

As described above, the connecting pipes 1 and 10 according to the present invention have the constituent members all having heat resistance, insulation property and corrosion resistance, and are deteriorated in the operating temperature of the fuel cell and the phosphoric acid atmosphere. Since it does not occur, it can be used as a piping material for supplying cooling water or fuel gas in the fuel cell. In particular, in the present invention, since the joint member is heat-sealed to the pipe body, the airtightness of the joint portion between the two is improved and the reliability is greatly improved, and the pipe body made of fluororesin is tightened from the outside. Since it is connected to the connected pipe of the fuel cell without applying any force, no creep phenomenon occurs on the pipe wall. Therefore, even in the heat cycle as described above, there is no change in the sealing property of the connecting portion with the pipe to be connected, and the durability is also improved.

In each of the above-mentioned embodiments, the other end side portion of the joint member is heat-sealed with the end portion of the pipe body fitted internally, but in contrast to this, the pipe body is joined by the joint member. It may be heat-sealed in the state of being fitted inside. Further, in the embodiment, one end portion of the fuel cell connecting pipe has been described, but the joint member to be joined to the other end portion need not necessarily have the same shape as that of the one joint member. For example, one connecting portion may have a pipe shape and the other connecting portion may have a screw. Further, in addition to the tube body that is heat-sealed to the joint member, which has a single-layer structure without a pressure-proof reinforcing layer as in the above embodiment, a glass fiber braid is embedded in the tube wall to increase the pressure resistance. It is also possible to use other items, and they are selected as appropriate according to the conditions of use.

[0015]

[Effect of device]

 As explained above, the connecting pipe for a fuel cell according to the present invention has a joint member made of a fluororesin having a connecting portion with a pipe to be connected in the fuel cell at the end of the pipe body made of the fluororesin. Since they are heat-sealed, it is possible to secure sufficient sealing performance at the joint with the pipe to be connected, even for heat cycles from room temperature to about 200 ° C, and further reduce manufacturing costs. The effect is extremely large.

[Brief description of drawings]

FIG. 1 is a partially cutaway front view of an end portion showing a first embodiment of a fuel cell connecting pipe according to the present invention.

FIG. 2 is a partially cutaway front view of an end portion showing a second embodiment of the fuel cell connecting pipe according to the present invention.

[Explanation of symbols]

 1,10 Fuel cell connection pipe 2,12 Tubular body 3,11 Joint member 3b, 11b Connection part

Claims (1)

[Scope of utility model registration request] 1. A tubular joint member made of a fluorine-based resin, having a connecting portion at one end for connecting a pipe to be connected in a fuel cell,
A connecting tube for a fuel cell, which is heat-sealed to the end of a tube made of a fluororesin at the other end.