JP2007154799A - Pump and fuel cell system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a pump in which a rotor is hardly frozen in a pump room during pump stoppage in a low temperature environment, and can be actuated promptly. <P>SOLUTION: In a pump that compresses fluid by rotating a rotor by a rotating shaft in a pump room, the rotor has a capillary, and an opening of one end of the capillary is formed on the surface of the rotor. Even if the condensation of residual moisture occurs in a low temperature environment, water is induced to a capillary side by a capillary phenomenon, and consequently no moisture remains on the rotor surface. Therefore, the locking of the rotor in the pump room resulting from the freezing of water can be prevented. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a pump that is unlikely to freeze even at low temperatures, and a fuel cell system using such a pump.

  The fuel cell system is a system in which fuel gas and oxidant gas are supplied to a fuel cell, and electricity is generated using an electrochemical reaction of these gases in the battery body. This electrochemical reaction generates water in the battery body, and this water is contained in fuel off-gas (fuel gas discharged from the fuel cell body) and oxidant off-gas (oxidant gas discharged from the fuel cell body). It is discharged from the battery body in a contained state.

  Therefore, when the temperature of the outside air decreases to, for example, below freezing point when the fuel cell system is stopped, moisture in the gas remaining in the components such as valves and pipes provided in the gas flow path of the system is condensed. Component parts may freeze. In such a case, even if an attempt is made to start the fuel cell system thereafter, the fuel cell system may not be started, or even if it can be started, normal operation may not be performed. In particular, if a gas supply system device such as a pump freezes, it becomes impossible to supply fuel gas and oxidant gas, and a considerable time is required until the entire system can be started. For example, when a rotary compression pump or the like is used as a fuel pump, if freezing occurs in a state where moisture is interposed in the gap between the rotor and the casing inner surface facing the rotor, the rotor is fixed to the casing, and the operation is resumed. Sometimes the pump could not be started quickly.

As a method for avoiding such a malfunction due to freezing of the pump, it has been proposed to provide grooves on the front and back surfaces of the rotor in the direction of the rotation axis and the inner surface of the casing facing the rotor (see Patent Document 1). In such a pump structure, when the freezing occurs between the rotor and the inner surface of the casing facing the rotor, it is possible to reduce the fixing area due to the freezing. It can be disengaged and normal rotational motion can be started.
JP 2005-150298 A

  However, in the technique of Patent Literature 1, although the fixing region due to freezing can be reduced, when the generated water in the offgas or the condensed water generated in the pump chamber enters the groove, fixing due to freezing occurs. Therefore, in such a case, when starting the pump from a low temperature environment, there is a problem that it still takes time to start. Further, there is a problem that the surface of the rotor is damaged by the ice particles.

  The present invention has been made in view of such a problem, and uses a pump that can hardly start a rotor due to water freezing even in a low-temperature environment and can be quickly started at the next start-up, and such a pump. An object is to provide a fuel cell system.

  In order to achieve the above object, the present invention provides a pump that compresses fluid by rotating a rotor installed in a pump chamber with a rotating shaft, and the rotor has a capillary tube, and is provided at one end of the capillary tube. There is provided a pump characterized in that the opening is provided in the surface of the rotor. In the pump of the present invention, even if moisture remains in the pump chamber, the water is guided to another place from the rotor surface via a capillary tube installed in the rotor by capillary action. Therefore, moisture does not remain on the rotor surface, and the rotor can be prevented from being fixed in the pump chamber.

  Here, it is preferable that the opening at one end of the capillary tube is installed in a region on the side surface in the direction of the rotation axis of the rotor that is close to and opposed to the inner surface of the pump chamber. In this case, the water is guided through the openings installed in the area as described above. Accordingly, water does not accumulate in the region of the rotor, and the rotor can be more reliably prevented from being frozen due to water freezing in this region.

  Or the said capillary tube may be comprised by the some groove | channel which has an opening in the area | region which adjoins and faces the inner surface of a pump chamber of the side surface of the rotating shaft direction of the said rotor. In this case, more residual water can be induced from the rotor surface.

  Further, the other end of the capillary tube may be a closed end. As a result, it is possible to store the induced moisture in the capillary tube.

  Alternatively, the other end of the capillary tube may be an opening provided on at least one of the front and back surfaces in the rotation axis direction of the rotor. As a result, the moisture on the front and back surfaces in the rotation axis direction of the rotor can be guided to the capillary side, and the fixation of the rotor due to freezing of water can be more effectively suppressed.

  Furthermore, the front and back surfaces in the rotation axis direction of the rotor have guide portions formed to be lower than the height level of the front and back surfaces, and the other end of the capillary tube is an opening provided in the guide portion. It may be. Thereby, the water | moisture content of the front and back of the rotating shaft direction of a rotor can be guide | induced to the capillary side more reliably.

  A member having a larger elastic modulus than the rotor itself may be disposed in the opening at one end of the capillary tube. In this case, by utilizing the deformation of this member during the rotation of the rotor, the ice in the capillary can be easily crushed, so that the crushed ice can be quickly discharged from the capillary by the centrifugal force of the rotation of the rotor. It becomes possible.

  A pump having any of the above features may be applied to a fuel cell system. In such a fuel cell system, freezing hardly occurs in the pump, and quick start-up is possible even in a low temperature environment.

  In the pump of the present invention, even if water freezes in the pump chamber under a low temperature environment, the rotor can be prevented from sticking. Further, by applying such a pump to the fuel cell system, the system can be quickly started even in a low temperature environment.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  In FIG. 1, the schematic block diagram of the Roots type pump 10 as one aspect | mode of the pump of this invention is shown. The present invention is not limited to the roots type pump, and can be similarly applied to other diaphragm type pumps.

  The roots type pump 10 includes a motor unit 45 and a pump unit 48. The motor unit 45 is closed at one end (the lower end in FIG. 1) and has a substantially cylindrical bottomed motor housing 111 having an opening at the other end (the upper end in the drawing). A partition wall 112 that is sealed and sealed so as to be closed is provided, and a motor chamber 113 is surrounded by an inner surface of the motor housing 111 and an inner surface of the partition wall 112. The pump portion 48 has a substantially oval cylindrical shape with a bottom that is open on one end side (the lower end side in FIG. 1), and is tightened and coupled to the pump casing 15 by a bolt 115 so as to close the opening. The pump chamber 20 is surrounded by the inner surface of the pump casing 15 and the inner surface of the bearing block 116.

  In the pump portion 48, a housing 118 having a bottomed substantially oval cylindrical shape smaller than the pump casing 15 is joined and fixed to the other end side (the upper end side in FIG. 1) of the pump casing 15. A gear chamber 119 is surrounded by the outer surface and the inner surface of the gear housing 118. The outer surface of the partition wall 112 and the outer surface of the bearing block 116 are joined and fixed via fastening means (not shown) such as bolts, whereby the motor unit 45 and the pump unit 48 are integrally configured. The joint surface between the motor housing 111 and the partition wall 112, the joint surface between the pump casing 15 and the bearing block 116, the joint surface between the pump casing 15 and the gear housing 118, and the joint between the partition wall 112 and the bearing block 116. O-rings 120 are installed on the surfaces to ensure airtightness.

  A bearing 122 is provided on the bottom 121 of the motor housing 111 at a position coaxial with the axis of the motor housing 111 and facing the motor chamber 113. The drive shaft (first rotating shaft) is provided with respect to the bearing 122. ) 35 is rotatably supported at one end (lower end in FIG. 1). The other end side of the first rotary shaft 35 extends through the partition wall 112, the bearing block 116, and the bottom portion 124 of the pump casing 15 to the gear chamber 119. The other end of the first rotating shaft 35 is rotatably supported by a bearing 125 provided at the bottom 124 of the pump casing 15, and an intermediate portion thereof is supported by a bearing 126 provided at the bearing block 116. It is inserted and supported in a rotatable state. In the motor chamber 113, a motor rotor 127 is attached to the first rotating shaft 35, and a motor stator 128 is attached to the motor housing 111 so as to be positioned on the outer peripheral side of the motor rotor 127. The motor rotor 127 and the motor stator 128 constitute an electric motor 129.

  In the pump chamber 20 of the pump unit 48, a second rotating shaft 40 that is parallel to the first rotating shaft 35 is provided with a bearing 131 provided on the bottom 124 of the pump casing 15 and a bearing provided on the bearing block 116. Both ends are supported by 132 and installed so as to be rotatable with respect to each other. In the pump chamber 20, a two-leaf drive rotor (first rotor) 50 and a driven rotor (second rotor) 60 are attached to the first rotating shaft 35 and the second rotating shaft 40, respectively. Yes. Further, the other end side of the second rotating shaft 40 extends through the bottom portion 124 of the pump casing 15 and into the gear chamber 119, similarly to the other end side of the first rotating shaft 35. . In the gear chamber 119, the first timing gear 70 fixed to the other end portion of the first rotating shaft 35 and the second timing gear 72 fixed to the other end portion of the second rotating shaft 40 are meshingly connected. Has been. A sealing 137 is provided at each sliding portion of the first rotating shaft 35 and the second rotating shaft 40 in the bearing block 116 and in the bottom portion 124 of the pump casing 15.

  Next, the internal structure of the pump chamber 20 in the pump unit 48 will be described in detail. In the present specification, the expressions “front and back surfaces in the direction of the rotation axis” and “side surfaces in the direction of the rotation axis” are used when representing the surface position of the rotor. “Front and back surfaces in the rotation axis direction” means two surfaces of the rotor through which the rotor rotation shaft passes, and “side surfaces in the rotation axis direction” means surfaces other than the “front and back surfaces in the rotation axis direction” of the rotor. means.

  In FIG. 2, sectional drawing in the pump chamber at the time of the action | operation of the roots type pump 10 of this invention is shown typically. In the Roots type pump 10 of the present invention, the pump casing 15 is formed in a substantially elliptical shape, and a pump chamber 20 is provided inside thereof. The pump casing 15 is provided with a suction port 25 for sucking fuel or oxidant off-gas (hereinafter simply referred to as off-gas) from the fuel cell into the pump chamber 20. The suction port 25 is preferably provided in the upper part of the pump casing 15 in the vertical direction. The pump casing 15 is provided with a discharge port 30 for discharging off-gas compressed in the pump chamber from the pump chamber 20. The discharge port 30 is preferably provided at the lower portion of the pump casing 15 in the vertical direction. As described above, the first rotor 50 and the second rotor 60 are installed in the pump chamber 20. The first rotor 50 is fixed to a first rotating shaft 35 that passes through the center O, and the first rotating shaft 35 is rotated by the electric motor 129 described above. The second rotor 60 is fixed to a second rotating shaft 40 that passes through the center P, and the second rotating shaft 40 extends to the outside of the pump chamber in parallel with the first rotating shaft 35. As described above, one ends of the first rotating shaft 35 and the second rotating shaft 40 are fixed to the first and second timing gears 70 and 72, respectively. , 72 are meshed with each other.

  When the first rotating shaft 35 is rotated by the electric motor 129, the first rotor 50 is rotated. At the same time, the second rotating shaft 40 is rotated in the direction opposite to the first rotating shaft 35 via the first and second timing gears 70 and 72. Accordingly, in the pump chamber 20, the first rotor 50 and the second rotor 60 are rotated in opposite directions as indicated by arrows in the figure. The rotors 50 and 60 rotate with a phase difference of 90 ° from each other, and cooperate with the inner surface of the pump chamber 20 to compress the off-gas sucked into the pump chamber 20. A minute gap is formed between the inner surface of the pump chamber 20 and each of the rotors 50 and 60 so that they do not contact each other even when they are closest to each other.

  Here, when the pump is used as a circulation pump of the fuel cell system, as shown in the background section, the off gas taken into the pump chamber 20 includes moisture generated by the cell reaction in the fuel cell body, A certain amount of moisture is introduced into the pump chamber 20 together with the off gas. Therefore, if the pump 10 is stopped with the off gas remaining in the pump chamber 20, the moisture in the off gas may condense in the pump chamber 20 in a low temperature environment, and freezing may occur. In particular, when water freezes in the gap between the rotors 50 and 60 and the inner surface of the pump casing 15 facing the rotors 50 and 60, the frozen water is thawed because the rotors 50 and 60 are fixed to the pump casing 15 and cannot rotate. The pump cannot be started until the pump is started, and there is a problem that it takes a long time to start the pump.

  However, in the pump 10 of the present invention, it is possible to avoid such a problem as follows.

  FIG. 3 shows a rotor 50 (or rotor 60, hereinafter the same) of the pump 10 of the present invention, and FIG. 4 shows a schematic view of the AA cross section of the rotor 50 viewed from the direction of the arrow. A large number of first openings 85 are provided in a region 54 (hereinafter referred to as a facing surface 54) closest to and facing the inner surface of the pump casing 15 on the side surface 52 of the rotor 50. Each of the openings 85 is connected to the groove 80, and the groove 80 extends in parallel to each other along the X-axis direction (longitudinal direction of the rotor 50) from the facing surface 54 toward the inside of the rotor 50. ing. FIG. 4 shows one cut surface, and the actual rotor 50 has a Y-axis (axis perpendicular to the X-axis) direction (for example, A′-A ′ line, A ″ -A ″ line). A plurality of rows of grooves 80 having the structure shown in FIG. 4 are formed. The depths of these grooves 80 are not particularly limited, but as will be described later, the moisture contained in the grooves while the pump is stopped and the frozen ice are quickly removed by the rotation of the rotor 50 during the operation of the pump. Need to be deep enough to be released. There are no particular restrictions on the dimensions of the first opening 85, but these openings 85 and grooves 80 have a role as capillaries for containing moisture inside the rotor by utilizing the capillary phenomenon, so that a maximum of 2, The opening width (or diameter) is preferably about 3 mm or less. In this embodiment, an example is shown in which four grooves 80 are arranged at equal intervals in the Z-axis direction (rotating axis direction) and the Y-axis direction, but the arrangement and number of grooves 80 are not particularly limited. Furthermore, in FIG. 4, the groove 80 has a rectangular cross-sectional shape, but it should be noted that the cross-sectional shape is not limited to this.

  By providing such an opening 85 and groove 80 on the facing surface 54 of the rotor 50 of the pump 10, moisture contained in the off-gas is condensed in the pump chamber 20 in a low-temperature environment, and the facing surface 54 of the rotor 50 is condensed. Even if water accumulates, the water is guided into the groove 80 from the first opening 85 of the rotor 50 by capillarity and is accommodated therein. Therefore, even if the pump 10 is placed in a low temperature environment where freezing of water occurs, the moisture is only frozen inside the groove 80, and the rotor 50 is fixed to the inner surface of the casing 15 facing the rotor 50. Can avoid the problem of moving.

  The water accommodated in the groove 80 while the pump is stopped is discharged from the groove 80 by the centrifugal force of the rotor 50 at the next startup of the pump 10. Also, the ice frozen in the groove 80 is thawed by the heat in the pump chamber 20 when the pump 10 is started or operating, and is discharged from the groove 80 by the centrifugal force of the rotor 50. Thus, when the pump is stopped in the next low temperature environment, these grooves 80 can be used again for moisture storage. Here, even if the ice frozen in the groove is not completely thawed, the fixing to the inner wall of the groove 80 is solved to some extent, and if there is a slight gap between the ice and the inner wall, the rotor It should be noted that the centrifugal force due to 50 rotations can eject the groove 80 as a small piece. That is, in a structure in which a groove for storing water is installed in a stationary body such as a casing, the water accumulated in the groove while the pump is stopped and the frozen water is completely thawed and liquid water is not completely discharged from the groove. Cannot be “empty”. Therefore, if the pump operation time is short, frozen ice is incompletely thawed and the pump stops before it is discharged as a liquid, the ice remains in the groove and the pump is stopped. There is a possibility that the groove does not sufficiently function as a storage portion for storing water. On the other hand, in the present invention, since the groove for containing water is provided inside the rotor, which is a rotating body, ice can be quickly discharged as described above, and such a problem is less likely to occur. Thereafter, the small pieces of liquid water or ice discharged from the groove 80 are discharged from the discharge port 30 to the outside of the pump.

  A variation of the present invention is shown in FIG. In this example, a member 84 such as rubber having a certain elasticity from the end of the groove 80 on the first opening 85 side and having a higher elastic modulus than the material of the rotor 50 is attached. In such a configuration, when the pump 10 is started in a state where the moisture stored in the groove 80 of the rotor 50 is frozen, the member 84 is deformed when the rotor 50 is rotated, so that stress is easily applied to the ice column in the groove 80. The ice column can be quickly crushed by the centrifugal force generated by the rotation of the rotor 50 and discharged from the groove 80. Therefore, it is possible to further shorten the time until ice frozen in the groove is discharged from the rotor during operation of the pump.

  6 and 7 show another embodiment. In the rotor 50 shown in FIG. 6, the shape of the groove 80 is different from that of the above-described embodiment. Each groove 80 has a second opening 86 on the inner side of the rotor 50, and the second opening 86 is provided on one of the front and back surfaces 51 of the rotor 50 in the Z-axis direction. In such a groove structure, moisture condensed on the front and back surfaces 51 of the rotor 50 in the Z-axis direction can be accommodated in the groove 80 in addition to the water at the position of the facing surface 54 described above. Therefore, it is possible to prevent moisture condensed on the front and back surfaces 51 in the Z-axis direction of the rotor 50 from freezing and fixing the rotor 50.

  The rotor 50 shown in FIG. 7 is another embodiment of the rotor 50 shown in FIG. In this example, the front and back surfaces 51 in the Z-axis direction of the rotor 50 are provided with guide portions 90 for guiding water into the grooves 80. The guide portion 90 is configured to be lower by a depth d than the height level of the front and back surfaces 51 of the rotor 50 in the Z-axis direction. The second opening 86 is installed in the accommodating portion 90. By providing such a guiding portion 90 in the rotor 50, moisture condensed on the front and back surfaces 51 in the Z-axis direction of the rotor 50 can be more reliably guided toward the groove 80.

  As described above, in the pump of the present invention, the large number of openings 85 are provided in the facing surface 54 of the side surface 52 of the rotor 50, and the grooves 80 connected to the openings are further provided. Can be accommodated. Accordingly, water hardly remains on the facing surface 54 of the rotor 50, and the rotor 50 can be prevented from sticking due to water freezing. This makes it possible to start the pump quickly even in a low temperature environment.

  In the above-described embodiment, an example in which a large number of grooves 80 are installed as capillaries for moving the moisture adhered and condensed on the side surface and the front and back surfaces of the rotor 50 in the rotation axis direction has been described. It is not limited. In other words, in the present invention, the water generated in the rotor 50 can be moved to another place by utilizing the capillary phenomenon, and this induced water or freezing is utilized by utilizing, for example, the rotation of the rotor. Any structure can be used as long as it has a structure capable of quickly discharging ice out of the system, not limited to the groove shape.

  The pump of the present invention can also be used as a fuel gas or oxidant gas pump of a fuel cell system. Next, an embodiment of a fuel cell system using the pump of the present invention will be described. In the following example, a system in which the pump according to the present invention is applied to a fuel off-gas circulation path will be described. However, the present invention can also be applied to the path on the oxidant gas side.

  FIG. 8 shows a configuration example of a fuel cell system according to the present invention. This system has a fuel cell main body 1, and the electric power generated in the fuel cell main body 1 can be used as a drive source of a vehicle or the like, for example. The fuel cell system also includes a fuel gas channel 2 for circulating fuel gas in the system and an oxidant gas channel 3 for circulating oxidant gas (air). In the following description, a system using hydrogen gas as fuel gas supplied to the fuel cell will be described as an example.

  The fuel gas flow path 2 discharges the fuel off gas from the fuel cell main body 1 and the fuel gas supply flow path 201 for supplying the fuel gas from the hydrogen fuel source such as the high-pressure hydrogen tank 200 to the fuel cell main body 1. And a fuel off-gas discharge passage 203 for the purpose. However, the fuel off-gas discharge flow path 203 is substantially a circulation flow path, and the fuel gas is supplied from the fuel cell main body 1 side through the gas-liquid separator 220 and the hydrogen pump 210 having the above-described characteristics according to the present invention. It is connected to the supply channel 201. Hereinafter, the fuel off-gas discharge channel 203 is also referred to as a circulation channel 203. A first branch channel 207 and a second branch channel 209 are connected to the circulation channel 203.

  Further, in the fuel gas supply channel 201 of the fuel gas channel 2, a normally closed electromagnetic valve 230 is disposed at the discharge port of the high-pressure hydrogen tank 200, and the pressure reducing valves 232, A normally closed pressure reducing valve 234 is arranged. On the other hand, a normally closed pressure reducing valve 240, a gas-liquid separator 220, a hydrogen pump 210, and a check valve 242 are arranged in this order in the circulation flow path 203 as viewed from the fuel cell main body 1 side. The first branch flow path 207 is connected to the gas-liquid separator 220, and a normally closed electromagnetic valve 244 is disposed in the middle thereof. The second branch channel 209 is connected to the circulation channel 203 between the outlet side of the hydrogen pump 210 and the connection point A between the circulation channel 203 and the fuel gas supply channel 201. A normally closed electromagnetic valve (purge valve) 246 and a diluter 250 are disposed in the second branch channel 209, and the other end of the second branch channel 209 on the outlet side of the diluter 250 is an oxidation which will be described later. It is connected to the agent off-gas discharge channel 303. The other end of the first branch flow path 207 is also connected to the oxidant off-gas discharge flow path 303.

  On the other hand, the oxidant gas channel 3 includes an oxidant gas supply channel 301 for supplying an oxidant gas to the fuel cell main body, and an oxidant offgas discharge channel for discharging the oxidant offgas from the fuel cell main body 1. 303.

  A compressor 305 and a humidifier 325 are disposed in the oxidant gas supply channel 301. Further, the humidifier 325 described above is installed in the oxidant off-gas discharge channel 303, and an electromagnetic valve (air pressure regulating valve) 309 is disposed between the humidifier 325 and the fuel cell main body 1.

  Here, a normal flow of the oxidant gas will be briefly described. During normal operation of the fuel cell system, the air in the atmosphere is taken in as oxidant gas by driving the compressor 305, passes through the oxidant gas supply channel 301, and is supplied to the fuel cell 1 via the humidifier 325. Is done. The supplied oxidant gas is consumed by an electrochemical reaction in the fuel cell 1 and then discharged as an oxidant off-gas. The discharged oxidant off-gas passes through the oxidant off-gas discharge channel 303 and is discharged to the outside.

  Next, the flow of hydrogen gas will be described. During normal operation, the solenoid valve 230 is opened, hydrogen gas is released from the high-pressure hydrogen tank 200, and the released hydrogen gas passes through the fuel gas supply channel 201 and is decompressed by the pressure reducing valve 232. The fuel cell main body 1 is supplied via the electromagnetic valve 234. The supplied hydrogen gas is consumed in an electrochemical reaction in the fuel cell 1 and then discharged as a hydrogen off gas. The discharged hydrogen off-gas passes through the circulation channel 203, and after moisture is removed by the gas-liquid separator 220, it is returned to the fuel gas supply channel 201 via the hydrogen pump 210 having the above-described characteristics, and again the fuel. Supplied to the battery body 1. Since the check valve 242 is provided between the connection point A between the fuel gas supply channel 201 and the circulation channel 203 and the hydrogen pump 210, the circulating hydrogen off-gas does not flow back. Normally, the electromagnetic valves 244 and 246 of the first and second branch flow paths 207 and 209 are closed. However, when these valves are opened as necessary, the gas-liquid separation is performed from the respective branch flow paths. A gas containing a large amount of water treated in the vessel 220 and a hydrogen off-gas that no longer needs to be circulated are discharged. These liquids and / or gases are discharged out of the system through the oxidant off-gas discharge channel 303.

  When such a fuel cell system is stopped in a low-temperature environment, the hydrogen pump 210 has the above-described characteristics. Therefore, even if hydrogen off-gas is contained in the pump chamber, the rotor is frozen by moisture in the pump chamber. Does not occur. Therefore, it is possible to start quickly when the fuel cell system is started next time.

  The configuration of the fuel cell system used for explaining the present invention is an example, and the present invention is not limited thereto. For example, in an actual fuel cell system, other components such as a solenoid valve and piping may be provided at a location not shown, and conversely, some components shown in FIG. 8 are omitted. It should be noted that this can happen.

It is a schematic sectional drawing of the pump of this invention. It is the schematic sectional drawing of the pump chamber which showed typically the relationship between a pump casing, a rotor, and a rotating shaft. It is a front view of the rotor of the pump by this invention. 3 is a cross-sectional view of the rotor of the pump according to the present invention, taken along the line AA in FIG. 3 is a schematic cross-sectional view of a rotor in which a highly elastic member 84 is installed around a first opening 85 of a groove 80. FIG. It is a figure which shows another shape of the groove | channel 80 which has the 2nd opening 86 in the front and back surfaces 51 of the rotating shaft direction of a rotor. It is a figure which shows another shape of the groove | channel 80 which has a 2nd opening in the guidance | induction part 90 installed in the front-and-back surface 51 of the rotating shaft direction of a rotor. It is a figure which shows an example of the fuel cell system which used the pump by this invention as a hydrogen circulation pump.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Fuel cell main body 2 Fuel gas flow path 3 Oxidant gas flow path 10 Pump 15 Pump casing 20 Pump chamber 25 Suction port 30 Discharge port 35 1st rotating shaft 40 2nd rotating shaft 45 Motor part 48 Pump part 50 1st Of the rotor 51 Front and back surfaces in the rotation axis direction 52 Rotor side surface 54 Opposing surface 60 Second rotor 70 First timing gear 72 Second timing gear 80 Groove 84 Elastic member 85 First opening 86 Second opening 90 Guide part 129 Electric motor 200 High-pressure hydrogen tank 201 Fuel gas supply flow path 203 Circulation flow path 207 First branch flow path 209 Second branch flow path 210 Hydrogen pump 220 Gas-liquid separator 230, 234, 240, 244 for fuel off-gas 246 Solenoid valve 232 Pressure reducing valve 242 Check valve 250 Diluter 301 Oxidant gas supply flow path 303 Oxidation Off gas discharge passage 305 compressor 309,344,510 solenoid valve 325 humidifier.

Claims (8)

A pump that compresses fluid by rotating a rotor installed in a pump chamber with a rotation shaft,
The rotor has a capillary, and an opening at one end of the capillary is provided on a surface of the rotor.   2. The pump according to claim 1, wherein the opening at one end of the capillary tube is installed in a region of the side surface in the rotation axis direction of the rotor that is close to and faces the inner surface of the pump chamber.   2. The pump according to claim 1, wherein the capillary is configured with a plurality of grooves having openings in a region facing the inner surface of the pump chamber on a side surface in the rotation axis direction of the rotor.   The pump according to claim 1, wherein the other end of the capillary tube is a closed end.   4. The pump according to claim 1, wherein the other end of the capillary tube is an opening provided on at least one of the front and back surfaces of the rotor in the rotation axis direction.   The front and back surfaces in the rotation axis direction of the rotor have guide portions formed to be lower than the height level of the front and back surfaces, and the other end of the capillary tube is an opening provided in the guide portion. The pump according to claim 5.   The pump according to any one of claims 1 to 6, wherein a member having an elastic modulus larger than that of the rotor itself is disposed in an opening at one end of the capillary tube.   A fuel cell system comprising the pump according to any one of claims 1 to 7.

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