Water separator including a riser pipe and a sealing element as well as a fuel cell including a water separator, and a motor vehicle including a fuel cell

Abstract

The invention relates to a water separator for separating product water from a fuel cell, a fuel cell including a water separator and a motor vehicle including a fuel cell. To design the water separator to be as compact as possible and to be able to operate it in a frost-proof manner, it is provided according to the invention that the water separator has a sealing element and a riser pipe extending through the sealing element.

Claims

1. A water separator for separating product water from a fuel cell, including: a separator tank for receiving the product water, the separator tank including: a first container; a riser pipe located in the first container and extending from a bottom of the first container; a primary outlet and a secondary outlet for discharging the product water from the first container, wherein: the primary outlet is located in a first section of the bottom of the first container that is exterior to where the riser pipe connects to the bottom of the first container, and the secondary outlet is connected to the riser pipe in a fluid conduction manner, and is located in a second section of the bottom of the first container, and a sealing element, designed to contact the first section of the bottom of the first container and seal the primary outlet in a fluid-tight manner in its sealing position, wherein the riser pipe extends through the sealing element.

2. The water separator as recited in claim 1, wherein the sealing element is movable relative to the riser pipe, and wherein the movement of the sealing element is guided through the riser pipe.

3. The water separator as recited in claim 1, wherein the sealing element runs at least partially around the riser pipe.

4. The water separator as recited in claim 1, wherein the separator tank has at least one additional primary outlet located in the first section of the bottom of the first container.

5. The water separator as recited in claim 1, wherein the wall of the riser pipe and a sealing part of the sealing element are designed as concentric rings.

6. The water separator as recited in claim 1, wherein the sealing element is designed as a floater, the sealing element being designed to be lifted up out of its sealing position by water in the first container only when the fill level of the first container exceeds a predefined value.

7. The water separator as recited in claim 6, wherein the water separator has a stop element, which is provided on the riser pipe and limits the maximum floating height of the sealing element.

8. The water separator as recited in claim 1, wherein: the separator tank has a second container attached to the bottom of the first container, and the first container and the second container are fluidically connected by the primary outlet and the secondary outlet.

9. A fuel cell further including a water separator for separating product water of the fuel cell, wherein the water separator is a water separator as recited in claim 1.

10. A motor vehicle including a power plant and a fuel cell connected to the power plant for transmitting operating power, wherein the fuel cell is a fuel cell as recited in claim 9.

11. The water separator as recited in claim 1, wherein the riser pipe comprises at least one inlet extending through a wall in the riser pipe.

12. The water separator as recited in claim 11, further comprising a second sealing element wherein the second sealing element closes the at least one inlet when the second sealing element is in its a sealing position.

13. The water separator as recited in claim 8, wherein the second container has a tertiary outlet located in a bottom of the second container.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) The present invention is explained below in exemplary embodiments on the basis of the accompanying drawings.

(2) FIG. 1 shows a schematic sectional representation of an exemplary embodiment of the water separator according to the present invention,

(3) FIG. 2 shows a schematic sectional representation of the exemplary embodiment in FIG. 1, wherein a sealing element of the water separator is shown in its sealing position,

(4) FIG. 3 shows a schematic sectional representation of another exemplary embodiment of the water separator according to the present invention,

(5) FIG. 4 shows another schematic sectional representation of the exemplary embodiment in FIG. 3,

(6) FIG. 5 shows a schematic representation of an exemplary embodiment of a fuel cell according to the present invention, and

(7) FIG. 6 shows a schematic representation of an exemplary embodiment of a motor vehicle according to the present invention.

DETAILED DESCRIPTION OF THE INVENTION

(8) The present invention is explained below as an example on the basis of specific embodiments with reference to the drawings. The various features of the exemplary specific embodiments may be combined independently of one another, as already explained with the individual advantageous embodiments.

(9) The design and function of a water separator according to the present invention is initially described with reference to the exemplary embodiment in FIG. 1.

(10) FIG. 1 shows water separator 1 according to the present invention for separating product water P of a fuel cell, including a separator tank 2. The representation in FIG. 1 is a lateral sectional representation. In the exemplary embodiment in FIG. 1, separator tank 2 has two primary outlets 3. Furthermore, water separator 1 of the exemplary embodiment in FIG. 1 is provided with a secondary outlet 4. Product water P separated by water separator 1 may flow from separator tank 2 through outlets 3, 4.

(11) Furthermore, water separator 1 has a riser pipe 5, which has a fluid-conducting connection to secondary outlet 4. For example, riser pipe 5 may contact secondary outlet 4 in a fluid-conducting manner, i.e., connecting it to conduct fluid to secondary outlet 4 so that product water P in riser pipe 5 is able to flow directly into secondary outlet 4. Secondary outlet 4 thus preferably opens into riser pipe 5.

(12) Secondary outlet 4 is provided at a distance from, for example, between primary outlets 3. The distance from primary outlets 3 to secondary outlet 4 is such that riser pipe 5 has a fluid-conducting connection only to secondary outlet 4 but not to one of primary outlets 3. Consequently only secondary outlet 4 opens into riser pipe 5 but not any one of primary outlets 3.

(13) Outlets 3, 4 extend through a bottom 6 of separator tank 2. To be able to supply product water P to a collecting line which flows through outlets 3, 4, multiple lines may be connected to outlets 3, 4, these lines leading to the collecting line.

(14) Bottom 6 may be designed as an intermediate bottom 6. A drain container 7, into which both primary outlets 3 and secondary outlet 4 may open, is preferably situated on one side of intermediate bottom 6 facing away from riser pipe 5.

(15) Drain container 7 may have a tertiary outlet 8 through which the water having run into drain container 7 is able to emerge therefrom and flow into a collecting line, for example. A valve 9 with which the outflow of water out of separator tank 2 may be influenced may be provided between tertiary outlet 8 and the collecting line. An inside diameter of tertiary outlet 8 is preferably smaller than an inside diameter of riser pipe 5. If tertiary outlet 8 is situated concentrically with riser pipe 5, for example, along central axis A of riser pipe 5, then water condensing on the inside wall of the riser pipe cannot drip directly into tertiary outlet 8 or into valve 9 so that an unwanted influx of condensed water into valve 9 is prevented. Drain container 7 may be an integral part or a section of separator tank 2 or a container designed separately and mounted on separator tank 2.

(16) Intermediate bottom 6 divides interior volume V1 of separator tank 2 into a separation volume V2, in which, among other things, riser pipe 5 and/or sealing element 10 may be situated, and a drain volume V3, which is delimited by drain container 7 and intermediate bottom 6.

(17) To be able to seal primary outlets 3 in a fluid-tight manner as needed, water separator 1 has a sealing element 10. In the exemplary embodiment in FIG. 1, sealing element 10 is shown in its operating position or release position B, in which sealing element 10 is situated at least partially and, for example, at the maximum distance from primary outlets 3 and consequently does not seal them in a fluid-tight manner. Sealing element 10 may run around the riser pipe transversely to its central axis A and may be guided by riser pipe 5 in its movement between operating position B and a sealing position (not shown in the exemplary embodiment in FIG. 1).

(18) Sealing element 10 may run more than 180 degrees around central axis A of riser pipe 5, so that sealing element 10 cannot easily slip down from riser pipe 5 transversely to central axis A. Sealing element 10 and optionally one or multiple sealing parts of sealing element 10 preferably run(s) completely around riser pipe 5, so that sealing element 10 may also seal primary outlets 3 even when sealing element 10 is rotated in its sealing position around central axis A. If water separator 1 is a water separator of a fuel cell or of a motor vehicle, then vibrations occurring during operation may rotate sealing element 10 around riser pipe 5. However, this does not result in defective closure of primary outlets 3 by sealing element 10 if its sealing part is designed in an annular shape or if sealing element 10 has multiple sealing parts, which jointly form a ring.

(19) Riser pipe 5 and sealing element 10 may be designed in such a way that an interior of sealing element 10 is designed to be essentially complementary to an exterior of riser pipe 5. In particular one annular sealing part or multiple sealing parts arranged to form a ring of sealing element 10, and a wall of riser pipe 5, may be shaped to form concentric rings.

(20) So that sealing element 10 cannot accidentally slip down from riser pipe 5 along central axis A, water separator 1 preferably has a stop element 11 for sealing element 10. Stop element 11 protrudes away from the end of riser pipe 5 facing away from intermediate bottom 6 and may surround riser pipe 5 in at least some sections or even completely. Alternatively, water separator 1 may have at least two stop elements 11 protruding in different directions away from riser pipe 5, for example, in opposite directions. The direction in which stop element 11 protrudes from riser pipe 5 preferably points transversely to central axis A and away from it in particular.

(21) Sealing element 10 may be designed as a floater, so that water present in water separator 1 may actuate sealing element 10 and in particular move it out of its sealing position in the direction of operating position B. In the exemplary embodiment in FIG. 1, separator tank 2 is essentially completely filled with product water P, so that a fill level F of separator tank 2 is higher than the end of riser pipe 5 pointing away from intermediate bottom 6, and sealing element 10 is in contact with stop element 11 due to buoyancy. In this case, product water P may readily flow out through primary outlets 3 and secondary outlet 4 when valve 9 is opened.

(22) FIG. 2 shows the exemplary embodiment in FIG. 1 having a lower fill level.

(23) In contrast with FIG. 1, less product water P is present in separator tank 2 in FIG. 2. Sealing element 10 is shown in its sealing position D, in which it seals primary outlets 3 in a fluid-tight manner. Sealing element 10 is in contact with intermediate bottom 6, even in the case of a fill level F of separator tank 2, as shown in FIG. 2, which is greater than zero but less than a thickness d of sealing element 10, in such a way that product water in separator tank 2 and in particular in its separation volume V2 cannot reach primary outlets 3 to any mentionable extent or not at all. However, secondary outlet 4 is still unsealed, so that product water may additionally flow into separator tank 2 through riser pipe 5 and secondary outlet 4 from separation volume V2 into drain volume V3.

(24) In sealing position D, at least the sealing part of sealing element 10 may be in contact with intermediate bottom 6 and may be forced against it by the weight of sealing element 10, for example. Intermediate bottom 6 thus forms an opposite sealing surface for sealing element 10.

(25) FIGS. 3 and 4 schematically show another exemplary embodiment of water separator 1 according to the present invention having different fill levels. The same reference numerals are used for elements corresponding in design and/or function to elements of the previous exemplary embodiment. For the sake of brevity, only the differences in comparison with the previous exemplary embodiment are discussed below.

(26) In the exemplary embodiment in FIGS. 3 and 4, water separator 1 has two sealing elements 10, 10a, situated one above the other along riser pipe 5 during operation of water separator 1. To define operating position B of sealing element 10, water separator 1 has an additional stop element 11a, which is situated between primary outlets 3 and stop element 11. Additional stop element 11a in particular is situated at a distance from stop element 11 and from bottom 6 and is mounted on riser pipe 5, for example. Additional stop element 11a is preferably situated between two sealing elements 10, 10a and defines sealing and operating positions D, Da, B, Ba of two sealing elements 10, 10a. Sealing elements 10, 10a are movable between their sealing positions D, Da and their operating positions B, Ba. Sealing element 10 is thus displaceable between bottom 6 and additional stop element 11a, and sealing element 10a is displaceable between additional stop element 11a and stop element 11.

(27) Sealing position D of lower sealing element 10 corresponds to sealing position D of sealing element 10 of the previous exemplary embodiment. However, in the exemplary embodiment in FIGS. 3 and 4, operating position B of sealing element 10 lies along riser pipe 5 and, as viewed from bottom 6, in front of operating position B of sealing element 10 in the previous exemplary embodiment. In its operating position B, sealing element 10 is in contact with additional stop element 11a, for example, when the level of product water P inside the separator tank is at or above the height of additional stop element 11a.

(28) In its operating position Ba, additional sealing element 10a, like sealing element 10 in the previous exemplary embodiment, may be in contact with stop element 11. In its sealing position Da, additional sealing element 10a may be in contact with additional stop element 11a, preferably on its side facing away from bottom 6.

(29) Riser pipe 5 may have at least one inlet 12, which seals additional sealing element 10a in its sealing position Da and is accessible in operating position Ba of sealing element 10a. For example, inlet 12 may extend through a wall in riser pipe 5 and may be adjacent to additional stop element 11a or may at least be situated in the vicinity thereof.

(30) The end of riser pipe 5 pointing away from bottom 6 may be sealed by stop element 11, for example.

(31) If water separator 1 is filled only partially with product water P, so that product water P does not rise above additional stop element 11a or not significantly, additional sealing element 10a may be situated in its lowest possible position, i.e., in its sealing position Da, and may close at least one inlet 12. This makes it possible to prevent a gas, such as hydrogen, which may be present above product water P, from being able to flow out of water separator 1 through riser pipe 5 to outlet 4 and from there through the valve.

(32) If water separator 1 has been emptied and contains very little or no product water P, condensate may form due to cooling. The condensate may accumulate in the lower area of separator tank 2. In order to prevent blockage of valve 9 due to frozen water therein, it is desirable here for the condensate not to run into valve 9. Sealing element 10 preferably does not move out of its sealing position D in the direction of its operating position B immediately after the influx of new product water P, so that product water P cannot flow into valve 9 and freeze there at low temperatures, i.e., at temperatures below the freezing point of water.

(33) It may happen that frozen condensate or frozen residues of product water are present on bottom 6 and prevent movement of sealing element 10 away from bottom 6. Product water P flowing into separator tank 2 may accumulate during operation, causing the product water level inside separator tank 2 to rise. If the product water level reaches additional sealing element 10a, it may be moved by product water P out of its sealing position Da, so that product water P is able to flow out of separator tank 2, namely through at least one inlet 12 into riser pipe 5 and from there through outlet 4 opening into riser pipe 5.

(34) FIG. 5 schematically shows an exemplary embodiment of a fuel cell according to the present invention, including a water separator 1. The same reference numerals are used for elements which correspond in function and/or design to elements of the exemplary embodiment in FIGS. 1 and 2.

(35) Fuel cell 20 is, for example, a fuel cell 20 for a motor vehicle and has a fuel cell stack 21, which is dimensioned in such a way that, for example, the electricity generatable by fuel cell 20 is at least partially sufficient to drive the motor vehicle.

(36) To be able to supply fuel cell stack 21 with operating media, fuel cell 20 has an anode gas path 22 for conducting the operating medium anode gas to fuel cell stack 21 and a cathode gas path 23 for conducting the operating medium cathode gas to fuel cell stack 21. Anode gas path 22 and cathode gas path 23 each have an inlet section 22a, 23a, through which the corresponding operating medium may be conducted to fuel cell stack 21.

(37) Furthermore, anode gas path 22 and cathode gas path 23 both have an exhaust gas section 22b, 23b, through which exhaust gases from fuel cell stack 21 may flow out. One water separator 1 may be provided along each exhaust gas section 22b, 23b, to remove product water P from the exhaust gases of fuel cell stack 21. In the exemplary embodiment in FIG. 3, at least exhaust gas section 22b of anode gas path 22 has a water separator 1, so water may be removed by water separator 1 from anode exhaust gas flowing through anode gas path 22.

(38) Exhaust gas section 23b of cathode gas path 23 may extend through a water separator 1. Fuel cell 20 may thus have at least one water separator 1, through which either anode gas path 22 or cathode gas path 23 passes. Alternatively, not just one of gas paths 22, 23 but both anode gas path 22 and cathode gas path 23 may extend through one water separator 1. Two water separators 1 may optionally be provided, in which case cathode exhaust gas path 23 [sic] may extend through one water separator 1 and cathode gas path 23 may extend through the other water separator 1.

(39) Product water P separated from anode gas path 22 by water separator 1 may be supplied to exhaust gas section 23b of cathode gas path 23 according to the exemplary embodiment in FIG. 5, to enable its discharge through exhaust gas section 23b of cathode gas path 23, so that separate draining of product water P from the anode exhaust gas is unnecessary.

(40) In the exemplary embodiment in FIG. 3, the at least one water separator 1 is preferably designed according to the exemplary embodiment in FIGS. 1 and 2.

(41) FIG. 6 schematically shows an exemplary embodiment of a motor vehicle 30 according to the present invention, including a fuel cell 20 and a power plant 31. The same reference numerals have been used for elements which correspond in function and/or design to elements of the exemplary embodiment in FIG. 3.

(42) Power plant 31 is designed to at least partially drive motor vehicle 30. Operating power for power plant 31 is made available at least partially by fuel cell 20 during operation. Fuel cell 20 in the exemplary embodiment in FIG. 4 is preferably designed according to the exemplary embodiment in FIG. 3 and is connected to power plant 31 by an operating power line 32 for transmitting operating power.

LIST OF REFERENCE NUMERALS

(43) 1 water separator

(44) 2 separator tank

(45) 3 primary outlets

(46) 4 secondary outlets

(47) 5 riser pipe

(48) 6 intermediate bottom

(49) 7 drain container

(50) 8 tertiary outlet

(51) 9 valve

(52) 10, 10a sealing element

(53) 11, 11a stop element

(54) 12 inlet

(55) 20 fuel cell

(56) 21 fuel cell stack

(57) 22 anode gas path

(58) 23 cathode gas path

(59) 22a, 23a inlet section

(60) 22b, 23b exhaust gas section

(61) 30 motor vehicle

(62) 31 power plant

(63) 32 operating power line

(64) A central axis

(65) B, Ba operating/release position

(66) D, Da sealing position

(67) P product water

(68) V1 internal volume of the primary outlets

(69) V2 separation volume

(70) V3 drain volume