LIQUID SEPARATOR

Abstract

The invention relates to a liquid separator (17) for a gas flow charged with liquid, having an inner volume (21) which has at least one baffle element (23) and a collection area (24) for the separated liquid.

The invention is characterized in that a heat-conducting element (30) made of a material having good heat conductivity is arranged in the collection area (24) and protrudes in the direction of the at least one baffle element (23) into the gas flow (25) in the inner volume (21), wherein the baffle element (23) is made from a material which conducts heat less well than the heat-conducting element (30).

Claims

1. A liquid separator for a gas flow charged with liquid, having an inner volume, which has at least one baffle element and a collection area for the separated liquid, wherein a heat-conducting element made of a material with good heat conductivity is arranged in the collection area and protrudes in the direction of the at least one baffle element into the gas flow in the inner volume, wherein the baffle element is made from a material which conducts heat less well than the heat-conducting element.

2. The liquid separator as claimed in claim 1, wherein the heat-conducting element and the at least one baffle element are connected to one another.

3. The liquid separator as claimed in claim 1, wherein the heat-conducting element is made of metal and the at least one baffle element is made of plastic.

4. The liquid separator as claimed in claim 2, wherein the heat-conducting element is made of a metal sheet element and a connection element to the at least one baffle element.

5. The liquid separator as claimed in claim 1, wherein the heat-conducting element has one or more plates, which are smaller in area than the cross section of the inner volume through which flow can take place.

6. The liquid separator as claimed in claim 1, wherein the heat-conducting element has at least one perforated plate, multiple rods, and/or at least one grid.

7. The liquid separator as claimed in claim 1, wherein a housing around the inner volume and the at least one baffle element are formed in one piece.

8. The liquid separator as claimed in claim 1, wherein exactly one baffle element is provided.

9. The liquid separator as claimed in claim 1, wherein the collection area has a drain valve or is connected directly thereto, via which the collection area is switchably connected to the environment or a further component.

10. A use of the liquid separator as claimed in claim 1 as a water separator in an exhaust gas flow of a fuel cell system.

11. The liquid separator as claimed in claim 2, wherein the heat-conducting element is made of metal and the at least one baffle element is made of plastic.

12. The liquid separator as claimed in claim 3, wherein the heat-conducting element is made of a metal sheet element and a connection element to the at least one baffle element.

13. A use of the liquid separator as claimed in claim 2 as a water separator in an exhaust gas flow of a fuel cell system.

14. A use of the liquid separator as claimed in claim 3 as a water separator in an exhaust gas flow of a fuel cell system.

15. A use of the liquid separator as claimed in claim 4 as a water separator in an exhaust gas flow of a fuel cell system.

16. A use of the liquid separator as claimed in claim 5 as a water separator in an exhaust gas flow of a fuel cell system.

17. A use of the liquid separator as claimed in claim 6 as a water separator in an exhaust gas flow of a fuel cell system.

18. A use of the liquid separator as claimed in claim 7 as a water separator in an exhaust gas flow of a fuel cell system.

19. A use of the liquid separator as claimed in claim 8 as a water separator in an exhaust gas flow of a fuel cell system.

20. A use of the liquid separator as claimed in claim 9 as a water separator in an exhaust gas flow of a fuel cell system.

Description

[0018] Further advantageous embodiments of the liquid separator according to the invention and the use thereof result from the exemplary embodiment, which is described in more detail hereinafter with reference to the figures.

[0019] Thereby shows:

[0020] FIG. 1 an exemplary vehicle having a fuel cell system, which has a liquid separator according to the invention as a water separator; and

[0021] FIG. 2 a cross section through a possible structure of the liquid separator according to the invention.

[0022] In the illustration of FIG. 1, a very schematically indicated vehicle 1 can be seen, which is to have a fuel cell system 2, which is intended to provide electrical power, in particular to provide electrical drive power for the vehicle. The core of the fuel cell system 2 is formed by a fuel cell 3, which is typically designed as a stack of individual cells. The structure is also referred to hereinafter as a fuel cell stack. For example, it can be designed having proton-conducting membranes as the electrolyte, thus it can have so-called PEM fuel cells. The fuel cell stack 3 is supplied on its cathode side 6 with air from an air conveying device 4, for example a flow compressor, which flows via a supply air line 5 and a gas/gas humidifier 10 into the cathode side 6 of the fuel cell stack 3 in the embodiment shown here. Via an exhaust air line 7, the oxygen-depleted air flows in turn through the gas/gas humidifier 10 out of the cathode side 6 of the fuel cell stack 3. Moisture is given off to the supply air in the supply air line 5 via the humidifier 10 in this case. The exhaust air then enters an exhaust air turbine 8, in which it is expanded in order to recover heat energy and pressure energy. An electrical machine 11 is operatively connected to this exhaust air turbine 8 on the one hand and the flow compressor 4 on the other hand. This structure, which is also referred to as an electric turbocharger 20 or motor-assisted turbocharger, is used to efficiently supply air to the fuel cell system 2 and is known from the prior art to the extent that it does not need to be discussed further.

[0023] An anode side 12 of the fuel cell stack 3 is supplied with hydrogen from a compressed gas store 13 via a pressure control and metering valve 14. Hydrogen that has not been consumed returns via a recirculation line 16 from the anode side 12 of the fuel cell stack 3 to a gas jet pump 15 as a recirculation conveyor device and is mixed with fresh hydrogen, which is also used as a driving jet for the gas jet pump 15, and supplied back to the anode side 12. Alternatively or additionally to this gas jet pump 15, a recirculation fan could also be provided here. In the recirculation line 16 or in the structure for the recirculation of unconsumed hydrogen, referred to as the anode loop, there is now a liquid separator 17, which is connected to the environment via a drain valve 18 in the exemplary embodiment shown here. A connection, for example, to the exhaust air line 7 before or in particular after the exhaust air turbine 8 would be just as conceivable. All of this is clear enough to a person skilled in the art of fuel cell systems that it does not need to be discussed further. In the following, the liquid separator or water separator 17 in particular will now be described in more detail. In the representation of FIG. 2, its structure is shown schematically in a cross section. The water separator 17, a housing designated by 19, which is to be produced, for example, as an injection molded part made of plastic. The drain valve 18 is in direct contact with the housing 19, which surrounds an inner volume 21. It is now crucial for the functionality of the liquid separator 17 that an inflow opening 22, which is connected upstream to the recirculation line 16, is followed by a baffle element 23, which blocks the entire incident flow cross section for the gas flow charged with liquid from the recirculation line 16. This baffle element 23 can preferably be formed in one piece with the housing 19 and also made of plastic. The flow charged with the liquid droplets, which flows from the recirculation line 16 through the inflow opening 22 into the inner volume 21, therefore impacts against this baffle element 23 and is sharply deflected. The water contained therein collects at the baffle element 23 and, as shown here, drips in the direction of gravity g when the liquid separator 17 is used as intended, downwards and along a part of the housing 19 into a collection area 24, which is arranged therein below the part of the inner volume 21 through which gas flows and which is connected to the drain valve 18. The gas completely or largely freed from the liquid then flows according to the arrow designated by 25 through the inner volume 21 of the liquid separator 17 and through an outflow opening 26 upstream back into the recirculation line 16.

[0024] In the collection area 24 and projecting beyond it in the direction of the gas flow according to the arrow 25, a heat-conducting element 30 is now located, which is produced from an aluminum alloy, for example. It consists of a first metal sheet 31, which is at least partially arranged in the collection area 24 and protrudes into the liquid collecting there, which is indicated here by a liquid level. A connection element 32, which is also made of an aluminum alloy and is preferably made in one piece with the metal sheet 31 or is at least connected thereto with very good heat conductivity, for example welded, protrudes in the direction of the baffle element 23 and is preferably mechanically connected thereto, for example clipped, riveted, screwed, adhesively bonded, or the like. In principle, the connection element 32 can be designed as a perforated plate, as a certain number of rods, as a grid, or the like. The structure made up of one or more plates, which largely or not entirely block the flow cross section of the inner volume 21 perpendicular to the plane of the drawing, is also conceivable. In the case of multiple baffle elements 23, multiple connection elements 32 or one connection element 32 connecting them all to one another would accordingly also be conceivable.

[0025] The connection element 32 and partially also the plate 31 of the heat-conducting element 30 now absorb heat from the gas flow flowing according to the arrow 25. Together with the heat that remains in the liquid droplets, since the baffle element 23 is made of plastic and therefore has poor heat conductivity, this has the result that heat is introduced into the collection area 24 over relatively short paths of the heat-conducting element 30, in addition to the heat which is already contained in the liquid itself. In operation of the liquid separator or water separator 17, this results in very good heating of the liquid in the collection area 24, so that the risk of ice formation can be avoided or at least minimized.