JP4429068B2 - Branch pipe, piping assembly and fuel cell system - Google Patents

Description

  The present invention relates to a branch pipe, a pipe assembly, and a fuel cell system that are branched and joined to a fluid main pipe.

A conventional fuel cell system is provided with a diluter that mixes and dilutes oxygen off gas in order to reduce the concentration of hydrogen off gas discharged from the fuel cell to the outside (see, for example, Patent Document 1). .)
Japanese Patent Laid-Open No. 2003-203654 (page 3 and FIG. 1)

  By the way, as a fuel cell system, for example, in a case where a gas-liquid separator, a silencer, or the like is interposed in an oxygen off-gas exhaust pipe, the oxygen off-gas is branched from the exhaust pipe to guide it to the diluter. It is necessary to provide a separate branch pipe. However, the conventional fuel cell system described in Patent Document 1 does not consider the structure of the branch pipe, and it is difficult to cope with the above-described configuration. This type of branch pipe is desired to sufficiently extract oxygen off-gas from an exhaust pipe serving as a main pipe in order to sufficiently dilute the hydrogen off-gas.

  Accordingly, an object of the present invention is to provide a branch pipe, a pipe assembly, and a fuel cell system that can take out an appropriate amount of fluid from the main pipe and can suitably improve the connection structure with the main pipe. .

The branch pipe of the present invention is a branch pipe that is branched and joined to the main pipe, and is configured separately from the inner pipe and the inner pipe arranged in the main pipe, and communicates with the inner pipe, and outside the main pipe. And an outer tube, the inner tube is held by the main tube, and the outer tube is joined to the main tube. The inner pipe has a pipe section through which a fluid flows and a flange section provided at an end of the pipe section on the outer pipe side and held by the main pipe. The outer pipe is a pipe of the inner pipe. A pipe part communicating with the road part and a flange part provided at an end of the pipe part on the inner pipe side, in close contact with the flange part of the inner pipe and joining a peripheral part away from the close part to the main pipe And having.

According to this configuration, since the branch pipe is of a so-called dynamic pressure intake type, the fluid flowing through the main pipe can be appropriately taken out to the outer pipe by the inner pipe of the branch pipe arranged in the main pipe. . In addition, the inner pipe and the outer pipe are configured separately from each other, the inner pipe is held in the main pipe, and the outer pipe is joined to the main pipe, so that the branch pipe can be appropriately and easily attached to the main pipe as a whole. It becomes possible to join. Furthermore, since the molding process of the inner tube and the outer tube can be made separate, it is possible to increase the degree of freedom of each shape of the inner tube and the outer tube.
Further, the inner pipe is held by the main pipe through the flange portion, and the outer pipe is joined to the main pipe at the peripheral portion of the flange portion, and the portion removed from the joint portion is connected to the flange portion of the inner pipe. Closely, the pipe sections of both pipes communicate with each other. With such a simple connection structure, the branch pipe can be appropriately connected to the main pipe.
In addition, although a branch pipe and a main pipe can also be comprised with a metal pipe, it is preferable to comprise with resin from a viewpoint of weight reduction so that it may mention later. The outer tube and the main tube can be joined by screwing, but when these are made of resin, welding such as heat fusion is suitable.

In this case, the main pipe, the inner tube and the outer tube is made of a thermoplastic resin, the flange portion of A Sauter tube that is welded to the main pipe, preferred.

  According to this configuration, the overall weight can be reduced. In addition, since the inner tube and the outer tube are configured separately as described above, the inner tube is favorably deteriorated when the outer tube is welded to the main tube, as compared with the case where they are integrally formed. Can be suppressed. This also means reducing the weld shape.

  In this case, it is preferable that the outer pipe is welded to the inner pipe together with the main pipe.

  According to this configuration, the workability of welding can be improved, and the attachment of the inner pipe to the main pipe is stabilized. That is, even when a high-pressure fluid is used, the communication between the outer tube and the inner tube can be reliably maintained.

  In this case, it is preferable that the other end portion of the pipe portion of the inner pipe is open toward the upstream side of the main pipe.

  According to this configuration, the fluid flowing through the main pipe flows into the inner pipe without being resisted by the flow. Thereby, the fluid can be taken out more appropriately from the main pipe to the branch pipe. In addition, it is more preferable that the opening end surface of the pipe part of the inner pipe is orthogonal to the fluid flow direction.

  The pipe assembly of the present invention is a pipe assembly comprising the above-described branch pipe of the present invention and a main pipe joined to the branch pipe, and the peripheral portion of the flange portion of the outer pipe is joined to the peripheral wall of the main pipe. There are provided a joint, a recess that is connected to the inside of the joint and holds the flange portion of the inner pipe, and an opening that is formed at the bottom of the recess and allows the inner pipe to be inserted into the main pipe. It is what has been.

  According to this configuration, a main pipe is formed corresponding to each configuration of the inner pipe and the outer pipe of the branch pipe, and a pipe assembly that has an improved connection structure while appropriately securing the amount of fluid taken out by the branch pipe. Can be provided.

  The fuel cell system of the present invention communicates with a main pipe through which a processing gas for hydrogen off-gas treatment flows, a branch pipe of the present invention branched and joined to the main pipe, and a downstream side of the branch pipe. And a mixing section communicating with a pipe for hydrogen off-gas discharged from the battery.

  According to this configuration, the hydrogen off gas and the processing gas for processing the hydrogen off gas from the branch pipe flow into the mixing portion. At this time, a sufficient amount of the processing gas flows through the branch pipe of the present invention. Therefore, hydrogen in the hydrogen off gas can be reliably reduced in the mixing portion. In addition, it is preferable to comprise a mixing part with the combustor which burns the diluter which reduces the hydrogen concentration in hydrogen offgas, and the mixed gas which consists of hydrogen offgas and process gas. Further, as the processing gas, new oxygen gas supplied to the fuel cell, oxygen off-gas discharged from the fuel cell, secondary air not supplied to the fuel cell, or inert gas such as nitrogen can be used. As a fuel cell system, a fuel cell vehicle is typified as equipment equipped with the fuel cell system.

  According to the branch pipe, the pipe assembly, and the fuel cell system of the present invention, since the inner pipe and the outer pipe of the branch pipe are configured separately, the connection structure between the branch pipe and the main pipe can be suitably enhanced. In addition, an appropriate amount of fluid can be taken out from the main pipe into the branch pipe.

  Hereinafter, a branch pipe according to a preferred embodiment of the present invention will be described with reference to the accompanying drawings. This branch pipe is constituted by a so-called dynamic pressure intake type and has an improved connection structure with the main pipe. Below, the example which applied the piping assembly which consists of a branch pipe and a main pipe | tube to the oxygen off-gas exhaust system of a fuel cell system is demonstrated.

  As shown in FIG. 1, the fuel cell system 1 includes a solid molecular electrolyte type fuel cell 2 that generates electric power when supplied with oxygen gas (air) and hydrogen gas. The fuel cell 2 is configured as a stack structure in which a large number of cells are stacked. The fuel cell system 1 includes a hydrogen gas supply system 3 that supplies hydrogen gas to the fuel cell 2 and an oxygen gas supply system 4 that supplies oxygen gas to the fuel cell 2.

  The hydrogen gas supply system 3 is discharged from the fuel cell 2, a hydrogen tank 11 serving as a hydrogen supply source storing high-pressure hydrogen gas, a supply channel 12 for supplying the hydrogen gas in the hydrogen tank 11 to the fuel cell 2, and A circulation channel 14 for pumping hydrogen off-gas to the supply channel 12 by a pump 13 and a discharge channel 15 branched from the circulation channel 14 are provided. The fuel cell 2 is supplied with new hydrogen gas from the hydrogen tank 11 and hydrogen off-gas recirculated from the circulation passage 14.

  A regulator 17 that adjusts the pressure of the hydrogen gas is interposed in the supply flow path 12. The discharge flow path 15 is provided with an open / close valve 18 for opening and closing it, and a diluter 19 (mixing section) for reducing the hydrogen concentration of the hydrogen off-gas is provided downstream of the open / close valve 18. . The on-off valve 18 is periodically opened and closed, and the valve is opened, so that impurities in the hydrogen off-gas are guided to the diluter 19 through the discharge passage 15 together with the hydrogen off-gas.

  The oxygen gas supply system 4 includes a compressor 22 that takes in oxygen gas in the atmosphere and pumps it to the humidifier 21, a supply passage 23 that supplies the oxygen gas humidified by the humidifier 21 to the fuel cell 2, and the fuel cell 2. A flow path 24 that guides the oxygen off gas discharged from the humidifier 21, a discharge path 26 that guides the oxygen off gas from the humidifier 21 to the silencer 25, and a branch to the discharge flow path 26 on the upstream side of the silencer 25. And a shunt flow path 27 for guiding a part of the oxygen off gas to the diluter 19. The flow path 24, the discharge flow path 26, and the diversion flow path 27 mainly constitute an oxygen off-gas discharge system.

  In the humidifier 21, moisture exchange is performed between the oxygen gas and the oxygen off gas, and the oxygen off gas after the moisture exchange is discharged to the discharge channel 26. In the diluter 19, the oxygen off gas and the hydrogen off gas are mixed, and the hydrogen concentration of the hydrogen off gas is reduced. The hydrogen off-gas diluted by the diluter 19 is sent to the downstream side of the silencer 25 in the discharge flow channel 26 via the exhaust pipe 28 and further mixed with the oxygen off-gas that has passed through the silencer 25 to finally form exhaust gas. Exhausted into the atmosphere outside the system.

  The various flow paths of the fuel cell system 1 are composed of metal pipes such as SUS or non-metal pipes such as resin and rubber, and are appropriately connected by pipes or joints. In the present embodiment, in consideration of weight reduction, the structure around this branch is devised so that the oxygen off-gas in the discharge channel 26 can be appropriately taken out to the diversion channel 27, and the resin pipe is welded. A piping assembly 40 is configured.

  As shown in FIGS. 2 to 4, the pipe assembly 40 includes a main pipe 41 constituting the oxygen off-gas discharge flow path 26 and a branch pipe branchingly connected to the main pipe 41 and constituting the oxygen off-gas diversion flow path 27. 42. The main pipe 41 and the branch pipe 42 are configured by, for example, blow molding or injection molding of a thermoplastic resin such as polypropylene or polyethylene.

  The branch pipe 42 is formed to have a smaller channel cross-sectional area (pipe inner diameter) than the main pipe 41. The branch pipe 42 is configured separately from an inner pipe 51 arranged in the main pipe 41 and an outer pipe 52 arranged outside the main pipe 41 and communicating with the inner pipe 51.

  The inner pipe 51 includes a pipe section 61 through which oxygen off-gas flows and a flange section 62 that is integrally provided at the end of the pipe section 61 on the outer pipe 52 side and is held by the main pipe 41. As shown in FIG. The outer pipe 52 has a pipe part 71 through which oxygen off-gas flows, and a flange part 72 that is integrally provided at the end of the pipe part 71 on the inner pipe 51 side and is joined to the main pipe 41 by welding. As a whole, it is formed in a substantially inverted J shape when viewed from the front.

  The pipe part 61 of the inner pipe 51 and the pipe part 71 of the outer pipe 52 are formed with the same inner diameter, and they communicate with each other without a gap. The pipe 61 of the inner pipe 51 has an end facing the main pipe 41 that opens toward the upstream side of the main pipe 41. More specifically, the opening end face 64 of the pipe line portion 61 is orthogonal to the oxygen off-gas flow direction. For this reason, the oxygen off-gas flowing through the main pipe 41 is taken into the pipe section 61 of the inner pipe 51 without being countered, and the flow path is changed at a right angle in the pipe section 61, so that the outer pipe 52 is sent to the pipe line section 71.

  The flange portion 62 of the inner pipe 51 is integrally formed so as to expand from the end portion on the outer pipe 52 side of the duct portion 61 and is formed in a disc shape. The flange portion 62 is attached to a mounting recess 94 (described later) of the main pipe 41, whereby the inner pipe 51 is held on the main pipe 41 via the flange portion 62. Further, the flange portion 62 has an end surface on the outer tube 52 side in close contact with the flange portion 72 of the outer tube 52 and is welded thereto.

  The flange portion 72 of the outer pipe 52 is integrally formed so as to expand from the end portion on the inner pipe 51 side of the pipe line portion 71, and is formed in a disk shape. The flange portion 72 is formed larger than the flange portion 62 of the inner pipe 51. The flange 72 has an end surface on the inner tube 51 side welded to the flange portion 62 of the inner tube 51, and a peripheral portion removed from the welded portion is brought into close contact with a later-described joining surface 93 of the main tube 41. The

  The main pipe 41 includes a pipe section 81 through which oxygen off-gas flows, and a pipe connection section 82 that is formed at a predetermined position on the peripheral wall of the pipe section 81 corresponding to the branch pipe 42 and connects the branch pipe 42. It is integrally formed. The pipe part 61 of the inner pipe 51 is disposed inside the pipe part 81 of the main pipe 41, the flange part 62 of the inner pipe 51 is held by the pipe connection part 82 of the main pipe 41, and the flange part of the outer pipe 52. 72 is welded.

  The pipe connecting portion 82 includes a saddle portion 91 at the lower end formed in a bowl shape following the peripheral wall surface of the pipe portion 81, a rising portion 92 that rises from the saddle portion 91 in a substantially cylindrical shape, and an annular shape of the rising portion 92. The joint surface 93 (joint portion) serving as the upper end surface, the mounting recess 94 connected stepwise from the joint surface 93 inside, and the opening 95 formed at the bottom center of the mounting recess 94 are provided. is doing.

  The outer diameter of the rising portion 92 is formed corresponding to the outer diameter of the flange portion 72 of the outer pipe 52. A peripheral portion of the end surface of the flange portion 72 of the outer pipe 52 is welded to the joint surface 93. The opening 95 is formed to correspond to the outer diameter of the pipe part 61 of the inner pipe 51 and allows the pipe part 61 to be inserted into the main pipe 41. The opening edge that defines the opening 95 is in contact with the outer wall on the flange portion 62 side of the duct portion 61 without a substantial gap (note that a gap is provided in the drawing for easy understanding of the invention).

  The mounting recess 94 is formed corresponding to the thickness and the outer shape of the flange portion 62 of the inner pipe 51 and receives the flange portion 62 without any gap. That is, the mounting recess 94 abuts on the annular end surface of the flange portion 62, and the bottom surface 101 that regulates the mounting depth position of the inner pipe 51 via the flange portion 62 and the periphery that abuts on the peripheral surface of the flange portion 62. (In the drawing, a gap is provided in order to facilitate the understanding of the invention as described above.) The peripheral wall surface 102 regulates the mounting horizontal position of the inner pipe 51 together with the opening edge of the opening 95. The end surface of the flange portion 62 attached to the attachment recess 94 on the outer tube 52 side is substantially flush with the joint surface 93.

  Here, a method of connecting the main pipe 41 and the branch pipe 42 will be briefly described. First, only the inner pipe 51 is attached to the main pipe 41. At that time, the pipe section 61 of the inner pipe 51 is inserted from the opening 95, and the flange section 62 is seated in the mounting recess 94, The inner pipe 51 is held by the main pipe 41. Next, the flange portion 72 is welded to the joint surface 93 of the main tube 41 and the flange portion 62 of the inner tube 51 while aligning the outer tube 52 with respect to these (41, 51). As a result, the inner pipe 51, the outer pipe 52, and the main pipe 41 are integrated to complete a series of connection steps, and the pipe assembly 40 is configured.

  As described above, according to the present embodiment, since the inner pipe 51 is provided as the configuration of the branch pipe 42, the oxygen off-gas from the main pipe 41 can be taken out sufficiently and satisfactorily by the branch pipe 42. Further, since the branch pipe 42 is constituted by the inner pipe 51 and the outer pipe 52 separately, it is particularly useful in that the branch pipe 42 is joined to the main pipe 41 by welding.

  In other words, when the inner pipe 51 and the outer pipe 52 are integrally formed, the thermal degradation of the pipe section 61 of the inner pipe 51 is taken into consideration, and the outer pipe 52 is welded to the main pipe 41 from the pipe section 61. It is necessary to keep the area relatively far (for example, 10 mm or more).

  On the other hand, in the present embodiment, the inner pipe 51 configured separately is mainly held by the main pipe 41, and the outer pipe 52 is mainly welded to the main pipe 41. It is possible to appropriately prevent the thermal deterioration of the structure. Further, since it is not necessary to keep the welding region away, the branch pipe 42 can be welded to the main pipe 41 regardless of the size of the main pipe 41 such as the outer diameter. Furthermore, the freedom degree of design of each shape of the inner pipe | tube 51 of the branch pipe 42 and the outer pipe | tube 52 can be raised, and the branch pipe 42 corresponding to various fluids from which a taking-out flow rate and a property differ can be provided.

  In the present embodiment, the end surfaces of the flange portions 62 and 72 of the inner tube 51 and the outer tube 52 are also welded, but of course, the end surfaces may be simply brought into close contact with each other without welding. However, with the configuration as in the present embodiment, rattling of the inner tube 51 can be suitably prevented. Further, although the opening end face 64 of the inner pipe 51 is arranged on the upstream side of the main pipe 41, it can be inverted 180 degrees and arranged on the downstream side of the main pipe 41. By doing in this way, it becomes possible to introduce | transduce oxygen off gas into the branch pipe 42, avoiding that the water | moisture content contained in oxygen off gas is taken in into the branch pipe 42 side.

  In addition, in the configuration of the main pipe 41, the pipe line portion 81 and the pipe connection portion 82 are integrally formed, but of course, they may be formed separately. In this case, a part of the pipe line part 81 may be perforated, and a part corresponding to the pipe connection part 82 may be welded to the hole, but it goes without saying that an integral configuration as in this embodiment is preferable. Further, the “inner pipe 51” arranged in the main pipe 41 includes a case where a part thereof is exposed outside the main pipe 41, and mainly refers to a pipe whose main part is arranged in the main pipe 41.

  Furthermore, in the above description, the oxygen off gas is guided to the diluter 19 by the branch pipe 42. However, instead of this configuration, for example, the branch pipe 42 is connected to the main pipe 41 constituting the supply flow path 23. Alternatively, new oxygen gas fed to the humidifier 21 may be guided to the diluter 19. That is, as a processing gas for hydrogen off-gas processing that flows through the main pipe 41, not only oxygen off-gas but also new oxygen gas supplied to the fuel cell 2 may be used. However, not only the oxygen gas supplied to the fuel cell 2 but also an inert gas such as secondary air or nitrogen not supplied to the fuel cell 2 can be introduced into the main pipe as a processing gas for hydrogen off-gas processing. It is.

  Further, the branch pipe 42 of the present embodiment can be applied to branch supply of fluid other than oxygen gas, and can be applied to other piping systems other than the fuel cell system 1. Moreover, although the branch pipe 42 and the main pipe 41 are formed of a thermoplastic resin, they may of course be configured as metal pipes. Also, the joining of the outer pipe 52 and the main pipe 41 of the branch pipe 42 is not limited to welding, and female screws are engraved in the joint portion of the main pipe 41 and the flange portion 72 of the outer pipe 52, and these are bolted. Is also possible. Further, although the inner officer 51 is held by the main pipe 41 so as to be seated, at least one of the main pipe 41 and the outer pipe 52 sandwiching the inner pipe 51 is configured to hold the inner pipe 51. That's fine. Alternatively, the inner pipe 51 may be actively held by welding the inner pipe 51 to the outer pipe 52.

It is a block diagram which shows the structure of the fuel cell system which concerns on embodiment. It is a front view which shows the piping assembly containing the branch pipe which concerns on embodiment. It is a top view of the piping assembly shown in FIG. It is a right view of the piping assembly shown in FIG.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 Fuel cell system, 2 Fuel cell, 3 Hydrogen gas supply system, 4 Oxygen gas supply system, 40 Piping assembly, 41 Main pipe, 42 Branch pipe, 51 Inner pipe, 52 Outer pipe, 61 Pipe line part, 62 Flange part, 64 Open end face, 71 Pipe line part, 72 Flange part, 81 Pipe line part, 82 Pipe connection part, 93 Joining surface (joining part), 94 Mounting recess, 95 Opening part

Claims (6)

In the branch pipe that is branched and joined to the main pipe,
An inner pipe disposed in the main pipe;
The outer pipe is configured separately from the inner pipe and communicates with the inner pipe, and is disposed outside the main pipe.
The inner pipe is held by the main pipe;
The outer pipe is joined to the main pipe ,
The inner tube is
A conduit section through which fluid flows;
A flange portion provided at an end portion of the conduit portion on the outer tube side and held by the main tube;
The outer pipe has a conduit portion communicating with the conduit portion of the inner tube,
A branch pipe provided at an end portion of the pipe section on the inner pipe side, in close contact with the flange portion of the inner pipe, and a flange portion joined to the main pipe at a peripheral portion removed from the close portion . The main pipe, the inner pipe and the outer pipe are made of a thermoplastic resin,
The flange portion of the front Symbol outer pipe, the branch pipe according to claim 1 which is welded to the main pipe.   The branch pipe according to claim 2, wherein the outer pipe is welded to the inner pipe together with the main pipe. The branch pipe according to any one of claims 1 to 3 , wherein the other end of the pipe section of the inner pipe is open toward the upstream side of the main pipe. In the pipe assembly which consists of the branch pipe according to any one of claims 1 to 4 and the main pipe which joined the branch pipe,
On the peripheral wall of the main pipe,
A joining portion to which a peripheral portion of the flange portion of the outer pipe is joined;
A recess that continues to the inside of the joint and holds the flange of the inner tube;
An opening that is formed at the bottom of the recess and allows the conduit portion of the inner pipe to be inserted into the main pipe;
A piping assembly provided with A main through which a processing gas for hydrogen off-gas processing flows,
The branch pipe according to any one of claims 1 to 4 , which is branched and joined to the main pipe,
A mixing section communicating with the downstream side of the branch pipe and communicating with a pipe for hydrogen off-gas discharged from the fuel cell;
Fuel cell system provided.

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