WO2009059659A1

WO2009059659A1 - Device for separating liquid from a gas stream and fuel cell system of such a device

Info

Publication number: WO2009059659A1
Application number: PCT/EP2008/007752
Authority: WO
Inventors: Thomas Baur; Christoph Hettinger; Julia Lauth; Hans-Jörg SCHABEL
Original assignee: Daimler Ag; Ford Global Technologies, Llc
Priority date: 2007-11-08
Filing date: 2008-09-17
Publication date: 2009-05-14
Also published as: DE102007053163A1

Abstract

The invention relates to a device (1) for separating liquid from a gas stream, having a separator means (2), which comprises an inlet opening (3) for the gas stream loaded with liquid, and a receptacle (8) arranged at least in places below the inlet opening (3) for collecting the separated-off liquid, which device comprises an insert (9) of one-piece construction arranged in the separator means (2), which insert (6) takes the form of a deflection device for the gas stream flowing via the inlet opening (3) into the separator means (2) and of a slosh-over baffle for the liquid (9) collected in the receptacle (8). The invention also relates to a fuel cell system having such a device.

Description

Daimler AG and

Ford Global Technologies, LLC

DEVICE FOR SEPARATING LIQUID FROM A GAS STREAM AND FUEL CELL SYSTEM

OF SUCH A DEVICE

The invention relates to a device for separating liquid from a gas stream, having a separator means, which comprises an inlet opening for the gas stream loaded with liquid, and a receptacle, arranged at least in places below the inlet opening, for collecting the separated liquid.

A device and a method for separating liquid and gas are known from DE 101 02 188 A1 , at least two separation stages being involved. The first separation stage comprises a horizontally oriented inlet port for two-phase flow of gas and liquid. The two-phase flow supplied to the inlet port enters a funnel-shaped cyclone, wherein the gas flow is guided upwards therein and separated-off water is conveyed out via a pipe arranged at the lower funnel outlet. The pipe is connected to an outer housing, wherein outflow channels are incorporated into the first separation stage, which channels introduce water separated off in the second separation stage provided above the first separation stage downwards into this outlet pipe. The separator means is of relatively complex construction and in particular the first separation stage requires a relatively large amount of installation space due to its height and is made up of a large number of components.

A method and a device for separating liquid from a gas stream for a gas generating system in a fuel cell installation are additionally known from DE 101 29 098 A1. The device comprises a separator means, which comprises an inlet opening through which the gas stream loaded with liquid flows into an immersion tube, which is vertically oriented. The immersion tube is closed on the side thereof remote from the inlet opening, at least one opening being formed in a side wall of the immersion tube so as to open into a spiral conduction area. The base of the closed immersion tube thus serves as a baffle plate for deflecting the gas flow in the direction of the opening in the side wall of the immersion tube. Below the immersion tube there is provided a base plate for the load area, in which outlet openings are formed through which the separated-off liquid may enter a collecting area arranged therebelow. This device is also of complex configuration and requires a relatively large number of components.

It is the object of the present invention to provide a device by which reliable separation of the liquid from the gas stream may be ensured and which may be constructed with a reduced number of components. In particular, it is intended to ensure deflection of the gas stream and to prevent the liquid collected in a receptacle for collecting the separated liquid from sloshing out.

This object is achieved by a device comprising the features as claimed in claim 1 and a fuel cell system comprising the features as claimed in claim 15.

A device according to the invention for separating liquid from a gas stream comprises a separator means, which comprises an inlet opening for the gas stream loaded with liquid. Moreover, the device comprises a receptacle, arranged at least in places below the inlet opening, for collecting the separated-off liquid. An insert of one-piece construction is arranged in the separator means, which insert takes the form of a deflection device for the gas stream flowing into the separator means via the inlet opening and of a slosh-over baffle for the liquid collected in the receptacle. Such a configuration allows the number of components in the device to be reduced. The insert is designed as a multifunctional element. In addition to gas stream deflection, it additionally serves as a slosh-over baffle, the device being appropriately designed to ensure these at least two functions. The insert is thus provided in the separator means in such a way that at least these two stated functions are performed. It is thus not only the multifunctional nature of this particular element, namely of the one-piece insert, which is an essential concept of the invention, but also the particular positioning thereof in the separator means and the arrangement and design of the further components of the separator means and also of the device for separating liquid from the gas stream.

The one-piece configuration of the insert also allows simple production, in addition to providing a mechanically stable configuration. This allows cost savings to be made. Such a configuration of the insert may, not least, simplify assembly and maintenance. Such an integral configuration of an insert may, not least, also prevent the problem of tolerances compared with a configuration of such an insert made up of a plurality of separate components.

Preferably, the insert is of trough-like construction on a side remote from the receptacle and is designed with a curved surface on said side remote from the receptacle to deflect the gas stream. As a result of the in particular comerless curved surface, gas stream conduction may proceed particularly advantageously, and thus eddy formation and individual more rapid "flow phases" may be at least significantly reduced, in particular prevented completely. Due to the particular configuration of the insert, separation of the gas flow from the water-filled lower part is additionally integrally combined with a maximally uniform distribution of the gas stream in the direction of the water separator or a trap device.

Preferably, the curved surface is so designed that deflection of the gas stream by substantially 90° may be achieved. In particular, the gas stream enters the separator means substantially horizontally via the inlet opening and is then deflected upwards by the insert, in particular the curved surface thereof, it then attaining a substantially vertical flow direction.

In particular, the curved surface of the insert comprises at least one through recess. As a result of this configuration, separated-off liquid may drip through the insert and reach a receptacle for collecting the separated-off liquid arranged in particular below the insert.

Preferably, the at least one through recess is of slit-like construction.

In particular, the insert is provided with such shaping on its side remote from the receptacle as to deflect the gas stream by substantially 90°.

Preferably, the insert is bounded on its side remote from the receptacle by a partially circumferential wall, which comprises a recess on its side facing the inlet opening. The wall is thus not of completely circumferential construction, but rather comprises a type of opening, through which the inflowing gas stream may enter the insert, where it encounters the curved surface. Such a configuration of the insert allows the arriving gas stream to be conveyed and guided in a virtually defined manner through a bounded space in the insert. Deflection of the gas stream is thereby optimized.

Preferably, the wall comprises at least one through hole formed in the direction of the height of the wall. In this way too, water separated off at a particular location may pass via the insert into the receptacle arranged therebelow for collecting the separated-off liquid. Preferably, this vertically oriented hole is formed at one end of the wall.

Preferably, the insert is of plate-like construction on a side facing the liquid collected in the receptacle. As a result of this configuration, a very shallow configuration may be provided, which therefore requires minimal installation space while providing efficient protection against sloshing over of the water collected in the receptacle. Preferably, the insert is thus of dished or bowl-like construction. As a result of the in a first approximation substantially flat configuration of the bottom of the insert and thus of the side facing the liquid, the receiving area of the receptacle for the liquid may also be relatively large without the shaping of the insert being impaired with regard to size. This configuration of the insert not least provides a type of lid for the receptacle.

Preferably, the insert comprises a radially oriented, annular web on its side facing the receptacle. As a result of this configuration, substantially the entire area of the receptacle may be covered by the insert and thus sloshing over is prevented even more effectively. As a result of this arrangement of the web, however, jamming and anchoring in the receptacle may also not least be prevented.

In particular, this radially oriented web leads onto the outer side of the wall.

In particular, at least one through recess is formed in the web. In this way too, it is thus made possible for separated-off liquid from the gas stream to enter the receptacle arranged therebelow through the insert. Reliable collection of the liquid in the receptacle may thereby be ensured without separated-off liquid dripping past the side of the receptacle. Due precisely to the radially oriented web, a virtually horizontal additional surface is provided, in which such recesses may be introduced as then make it possible also to drain off the water arising and separated off at various positions reliably and purposefully into the receptacle. Preferably, the recess in the web is peripherally bounded, part of the periphery being formed by the outer side of the wall. At least one recess is thus formed directly adjacent to the wall, such that separated-off water running off the wall also passes directly into the recess or therethrough and enters the receptacle.

Provision may also be made for the radially oriented web to be positioned slightly obliquely relative to horizontal, and in particular to be bent upwards. This also allows automatic diversion of the separated-off water in the direction of the recesses formed in the web and ensures reliable diversion into the receptacle.

Preferably, the insert is also constructed as a bearing surface for a trap for liquid droplets. In particular, the trap comprises a mesh. Such a mesh is used particularly advantageously, when the gas stream flows therethrough, to enable trapping of the liquid droplets or the like and diversion thereof downwards due to gravity. Furthermore, such a mesh is relatively light and thus allows a low-weight configuration of the device.

The insert thus also further displays, in addition to its functions already stated of deflection device and slosh-over baffle, the mechanical function of a support or a bearing element for a trap arranged thereabove. Preferably, the trap rests at its lower edge on the top of the wall of the insert.

In particular, the insert is made of plastics. Preferably, the configuration may here take the form of an injection moulding. In addition to simple and inexpensive production, a very light component may also be obtained thereby. Furthermore, such a plastics configuration is also relatively low wear.

A further aspect of the invention relates to a fuel cell system having a device according to the invention or an advantageous configuration thereof. The fuel cell system comprises at least one fuel cell, in particular a fuel cell stack with a plurality of fuel cells. Preferably, the fuel cell takes the form of a PEM fuel cell. In particular, the fuel cell system takes the form of a mobile fuel cell system and is provided for use in a vehicle.

The device according to the invention and an advantageous configuration thereof is provided in such a fuel cell system preferably for separation of water in a gas stream flowing out from the cathode compartment and/or the anode compartment of the fuel cell. An exemplary embodiment of the invention is explained in greater detail below with reference to schematic drawings, in which:

Fig. 1 is a schematic sectional representation through components of a device according to the invention; and

Fig. 2 is a perspective plan view of an insert arranged in the separator means.

In the figures, elements which are the same or have the same function are provided with the same reference signs.

Fig. 1 is a schematic sectional representation of a separator means 2 of a device 1 for separating liquid from a gas stream. The device 1 is associated with a fuel cell system in a vehicle, the intention being to separate liquid from a gas stream flowing out of the cathode compartment and/or the anode compartment of a fuel cell.

The separator means 2 comprises an inlet opening 3, through which the gas stream enters the separator means 2 in the direction of arrow P. In the exemplary embodiment the gas stream inlet is thus horizontally oriented. The inlet opening 3 is associated with a port or pipe 4 extending into the separator means 2. The gas stream exits at an outlet opening 5 of the pipe 4 and flows into an insert 6, which is arranged in the separator means 2. The insert 6 is of one-piece construction and, as is further illustrated and explained below in Fig. 2, is of dished or bowl-shaped construction. As a result of this configuration, the insert 6 may be constructed with minimal structural height (dimensions in the y direction). In the exemplary embodiment, the insert 6 is made of plastics.

The insert 6 is designed as a deflection device for the gas stream flowing into the separator means 2 via the inlet opening 3 and additionally as a slosh-over baffle for the liquid 9 collected in a receptacle 8.

As is shown in the representation according to Fig. 1 , the insert 6 is arranged in the horizontal direction (x direction) substantially at the level of the pipe 4. In the vertical direction the insert 6 is positioned between the receptacle 8, which is arranged below the insert 6, and a trap 7, which is arranged above the insert 6. The trap 7 takes the form of a mesh. The pipe 4 and insert 6 serve as a support or bearing surface for the trap 7. The latter is thus seated on the insert 6.

The insert 6 extends in places into the inside of the receptacle 8. On its side 10 remote from the liquid 9, the insert comprises a wall 11 , which is only partially circumferential when viewed in the circumferential direction. On the side facing the outlet opening 5, the wall 11 comprises a recess or an opening, whereby the gas stream flowing through the pipe 4 may enter the insert 6. The wall 11 additionally bounds the insert 6 and the side 10 facing the trap 7. The surface 13 (Fig. 2) of this side 10 facing the trap 7 is of curved construction. This configuration enables virtually eddy-free upwards deflection of the gas stream towards the trap 7. The recess 12 in the side wall 11 may be constructed directly adjacent to the outlet opening 5 or indeed at a distance therefrom.

On the side 14 of the insert 6 facing the receptacle 8 and thus also the liquid 9, said insert is of substantially plate-like construction and preferably also designed in a first approximation to be substantially flat.

A radially oriented web 16 is formed on the outer side 15 of the wall 11 at this lower side 14.

In the exemplary embodiment, a plurality of through recesses are formed both in the curved surface 13 and in the web 16. Thus, a plurality of slit-like through holes 17 are formed in the curved surface 13, a plurality of slit-like recesses 18 likewise being formed in the circumferential web 16. The recesses 18 are preferably provided equidistantly. Furthermore, the peripherally bounded recesses 18 in the web 16 are formed in such a way that part of the periphery is formed by the outer side 15 of the wall 11. The recesses 18 are thus directly adjacent to the outer side 15. These recesses 18 also allow the thus separated liquid from the gas stream to enter directly the receptacle 8 arranged therebelow. Since, according to the illustration in Fig. 1 , the insert 6 is arranged at least partially inside the receptacle 8, the side 14 also serves as a type of lid for this receptacle 8. The arrangement in which the web 16 is arranged virtually inside the receptacle 8 not least prevents the separated-off water from flowing past the receptacle 8, it always being ensured that said water drips through the recesses 18 into the receptacle 8. Fig. 2 is a perspective plan view of the insert 6 showing the shaping and geometry thereof. The bowl- or cup-shaped construction is shown. It may be noted that a thickened portion is also provided at an end of the wall 11 facing the opening or recess 12, in which thickened portion a through recess 19 is formed. The recess 19 extends in the vertical direction (y direction), whereby water separated in this connection from the gas stream may also flow into the receptacle 8 arranged therebelow. The trap 7 preferably rests directly on the upper edge or top 20 of the wall 11.

Inside the insert 6 a raised portion 21 is formed on the side 10 facing the trap 7. This raised portion 21 comprises a cornerless, curved surface on the side 22 facing the recess 12 and thus also the outlet opening 5 of the pipe 4. In this way too, the inflowing gas stream may be deflected upwards, this proceeding in an eddy-free manner.

Furthermore, the height of the raised portion 21 is such that the trap 7 also rests on the top of this raised portion 21.

According to the illustration in Fig. 2, the recesses 17 are formed around the raised portion 21. The recesses 17,18,19 in the one-piece insert 6 serve as drainage channels, opening directly into the receptacle 8.

Furthermore, the separator means 2 comprises an additional diverter 23 (Fig. 1) in the area of the pipe 4, by which the water collected at the wall of the pipe 4 may be diverted directly into the receptacle 8.

The gas stream flowing upwards out of the trap 7 is in turn deflected as shown by the arrows, in particular deflected and discharged at an angle of substantially 90°.

List of reference signs

1 Device

2 Separator means

3 Inlet opening

4 Port or pipe

5 Outlet opening

6 Insert

7 Trap

8 Receptacle θ Liquid

10 Side of insert remote from liquid

11 Wall

12 Recess

13 Surface

14 Side of insert facing liquid

15 Outer side

16 Web

17,18,19 Recesses

20 Upper edge of wall

21 Raised portion

22 Surface

23 Diverter

P Direction of arrow

Claims

Daimler AG andFord Global Technologies, LLCPatent Claims

1. Device for separating liquid from a gas stream, having a separator means (2), which comprises an inlet opening (3) for the gas stream loaded with liquid, and a receptacle (8) arranged at least in places below the inlet opening (3) for collecting the separated-off liquid, characterized by an insert (6) of one-piece construction arranged in the separator means (2), which insert (6) takes the form of a deflection device for the gas stream flowing via the inlet opening (3) into the separator means (2) and of a slosh-over baffle for the liquid (9) collected in the receptacle (8).

2. Device according to Claim 1 , characterized in that the insert (6) is of trough-shaped construction on the side (10) thereof remote from the receptacle (8) and comprises a curved surface (13) for deflection of the gas stream.

3. Device according to Claim 2, characterized in that the curved surface (13) comprises at least one through recess (17).

4. Device according to one of the preceding claims, characterized in that the insert (6) comprises shaping on its side (10) remote from the receptacle (8), so as to deflect the gas stream by substantially 90°.

5. Device according to one of the preceding claims, characterized in that the insert (6) is bounded on its side (10) remote from the receptacle (8) by a partially circumferential wall (11), which comprises a recess (12) on its side facing the inlet opening (3).

6. Device according to Claim 5, characterized in that the wall (11) comprises at least one through hole (19) formed in the direction of the height of the wall (11).

7. Device according to one of the preceding claims, characterized in that the insert (6) is of plate-like construction on its side (14) facing the liquid (9) collected in the receptacle (8).

8. Device according to one of the preceding claims, characterized in that the insert (6) comprises a radially oriented, annular web (16) on its side (14) facing the receptacle (8).

9. Device according to Claims 5 and 8, characterized in that the web (16) leads onto the outer side (15) of the wall (11).

10. Device according to Claim 8 or 9, characterized in that the web (16) comprises at least one through recess (18).

11. Device according to Claim 10₁ characterized in that the recess (18) is peripherally bounded, part of the periphery being formed by the outer side (15) of the wall (11).

12. Device according to one of the preceding claims, characterized in that the insert (6) takes the form of a bearing surface for a trap (7), in particular a trap comprising a mesh, for liquid droplets.

13. Device according to one of the preceding claims, characterized in that the insert (6) is made of plastics.

14. Device according to one of the preceding claims, characterized in that the liquid arising upstream of the insert (6) may be diverted directly into the receptacle (8) upstream of the insert (6).

15. Fuel cell system having a device (1) according to one of the preceding claims.