EP1717517A2 - Evaporator arrangement, particularly for a car heating appliance or for a reformer - Google Patents

Abstract

A liquid supply line (34) feeds liquid to a porous evaporator medium (24), which is held by a carrier (18), through an opening in the carrier. The liquid supply line includes a first section (40) having a smaller wall strength and connected to the carrier, and a second section (42) adjacent the first section.

Description

The present invention relates to an evaporator assembly, in particular for a vehicle heater or reformer, comprising a porous evaporator medium carried on a carrier and a liquid feed line which feeds liquid through an opening in the carrier into the evaporator medium.

For example, in vehicle heaters used as auxiliary heaters or auxiliary heaters, which are constructed in the manner of an evaporator burner, it is known to initiate the liquid fuel required for combustion through a fuel feed into a porous evaporator medium. In the porous evaporator medium, the liquid fuel is distributed under capillary action and can be evaporated on a top exposed to a combustion chamber. In general, the porous evaporator medium is accommodated in a pot-like or dish-like carrier which is deformed in a bottom region in the direction away from the porous evaporator medium and thus forms an approximately cylindrical at least in its free end region into which the fuel supply line is inserted. In general, a connection is provided by soldering between the carrier and the fuel supply line.

In such arrangements, there is not only a problem in that between the supply line and the carrier a very stable and tight against the leakage of liquid compound must be provided, but that in that area in which the liquid, for example, liquid fuel, from the Supply line exits due to relatively high temperatures, the risk of boiling or a spontaneous fuel evaporation is, especially for low-boiling fuels. This can lead to high pollutant emissions and a very uneven Introduce the fuel into the porous evaporator medium.

It is the object of the present invention to design an evaporator arrangement mentioned at the beginning in such a way that, when it is possible to provide a stable connection between the liquid feed line and the carrier of the porous evaporator medium, the risk of excessive heating in that area in which the fuel is fed is diminished.

According to a first aspect of the invention, this object is achieved by an evaporator arrangement, in particular for a vehicle heater or a reformer, comprising porous evaporator medium carried on a carrier and a liquid feed line which feeds liquid through an opening in the carrier into the evaporator medium, the liquid feed line in a first region adjacent to the carrier is formed with a lower wall thickness than in a region further away from the carrier second region.

By providing a liquid feed line formed with stepped wall thickness, the heat transfer interaction between this and the strongly thermally influenced carrier is significantly reduced. The risk of heat introduction into the region of the liquid feed line adjoining the carrier can thus be reduced.

It is advantageous if an opening cross-section of the liquid supply line in the first region and in the second region is substantially equal. In this way it can be ensured that the fuel introduction capacity remains unaffected by those measures which lead to a reduced heat transfer.

According to a further aspect, the object mentioned at the outset is achieved by an evaporator arrangement, in particular for a vehicle heater or a reformer comprising porous evaporator medium carried on a carrier and a liquid feed line which feeds liquid through an opening in the carrier into the evaporator medium, wherein a liquid feed line attachment means is provided on the carrier and wherein a free end of the connection tab is in the direction of the porous evaporator medium is directed to.

With such a configuration, it becomes much easier to introduce the liquid supply line in this approach and to connect to the carrier in this area.

By way of example, the embodiment may be such that the carrier is deformed in a region surrounding the connection attachment in the direction away from the porous evaporation medium and provides a funnel-like introduction formation for the liquid supply conduit in a transition region to the connection attachment. Thus, not only the introduction is facilitated, but also an arrangement is provided in which a press fit between the carrier and the liquid supply line can be realized very easily.

In order to further increase the connection stability, it is proposed that the liquid supply line is materially connected to the carrier in the region of the introduction formation. Preferably, it may be provided here that the material-fit connection is provided by soldering or welding or adhesive bonding.

In addition to the fact that even deforming the carrier in the direction away from the porous evaporator medium in the region in which the fuel supply line opens, a reduced heat transfer to the fuel supply will entrain, the thermal decoupling can be further improved that the free End of the connection approach is at a distance from the evaporator medium.

According to a further aspect of the present invention, the object mentioned at the outset is achieved by an evaporator arrangement, in particular for a vehicle heater or a reformer, comprising porous evaporator medium carried on a carrier and a liquid feed line which feeds liquid through an opening in the carrier into the evaporator medium, wherein the liquid feed line opens into a distribution channel surrounding a porous liquid transfer medium and open to the latter.

In such a configuration, therefore, a direct liquid transfer contact between the Brennstoffzuführleitung and the porous evaporator medium does not take place, but this function is taken over by the porous liquid transfer medium. In this way, the excessive thermal load of the liquid feed line in the region in which the liquid exits from this, can be prevented.

Here, it can be provided, for example, that the distribution channel is provided in an introduction element receiving the liquid transfer medium and connected to the support.

In particular, when used in a heater, it is advantageous if the substantially cylindrically shaped liquid transfer medium penetrates at least partially and at a distance in Zündorgan.

According to a further aspect, the object mentioned at the outset is achieved by an evaporator arrangement, in particular for a vehicle heater or a reformer, comprising porous evaporator medium carried on a carrier and a liquid feed line which feeds liquid through an opening in the carrier into the evaporator medium, an assembly of Carrier and liquid supply line is assigned a support surface on which the other of these two modules is supported with an edge-like support area.

Here, therefore, an investment interaction between the liquid supply and the carrier or at this particular intended elements is obtained only in an edge or line area. Thus, with a stable support interaction, a minimum effective thermal transfer surface can be ensured.

In order to prevent the unwanted escape of the liquid to be transferred, it is proposed that the supporting interaction between the support surface and the support region produces a liquid-tight closure of the opening. The provision of additional sealing arrangements can thus be dispensed with.

In order to support this liquid-tight closure, it is proposed that the support region bears under pretension on the support surface. It can be provided, for example, that the bias is provided by an effective between the carrier and the liquid supply line spring. It is also possible that the bias voltage is provided by the porous evaporator medium.

Furthermore, the construction may be such that a disk-like support element having the support region is provided at an end region of the liquid supply line. In this case, then the support surface is realized in the region of the carrier. Alternatively, it is possible for the liquid supply line to provide the support surface in a widening region and for the support to provide the support region with an edge surrounding the opening.

Fig. 1

eine Längsschnittansicht einer erfindungsgemäß aufgebauten Verdampferanordnung;

Fig. 2

vergrößert einen Detailbereich einer derartigen Verdampferanordnung;

Fig.3

eine Verdampferbaugruppe einer erfindungsgemäßen Verdampferanordnung;

Fig. 4

eine der Darstellung der Fig. 2 entsprechende Darstellung einer alternativen Ausgestaltungsform;

Fig. 5

eine Abwandlung der in Fig. 4 dargestellten Ausgestaltungsform;

Fig. 6

eine weitere Abwandlung der in Fig. 4 dargestellten Ausgestaltungsform;

Fig.7

eine weitere Abwandlung der in Fig. 4 dargestellten Ausgestaltungsform.

The present invention will be described below in detail with reference to the accompanying drawings. It shows:

Fig. 1

a longitudinal sectional view of an inventively constructed Evaporator assembly;

Fig. 2

enlarges a detail area of such an evaporator arrangement;

Figure 3

an evaporator assembly of an evaporator assembly according to the invention;

Fig. 4

one of the representation of Figure 2 corresponding representation of an alternative embodiment.

Fig. 5

a modification of the embodiment shown in Figure 4;

Fig. 6

a further modification of the embodiment shown in Figure 4;

Figure 7

a further modification of the embodiment shown in Fig. 4.

In Fig. 1 with respect to its essential components designed here in the form of an evaporator burner 10 inventive evaporator arrangement is shown. The evaporator burner 10 includes a combustion chamber housing, generally designated 12, which surrounds a combustion chamber 14. In an end region of the combustion chamber housing 12, an evaporator assembly 16 is provided which essentially comprises a shell-like support 18 with a bottom region 20 and a peripheral wall region 22. In this shell-like support 18, a porous evaporator medium 24 constructed in multilayer form is provided here. This can be provided, for example, by non-woven material produced by sintering or in any other manner, which has such a porosity that the liquid fed in, in this case liquid fuel, is distributed by capillary action and then evaporated off at the surface exposed to the combustion chamber 14 can. On the outside of the bottom wall of the evaporator assembly 16, there is provided a heating element 26 formed like a heating coil or the like, through which the evaporator assembly can be heated to assist the liquid evaporation. The heating element 26 is covered by an insulating member 28 and a cover plate 30, and by a retaining ring 31, this entire arrangement is fixed to the combustion chamber housing 12. Further, an ignition member 32, for example in the form of a glow plug or the like, is provided on the combustion chamber housing 12 in order to ignite the mixture of fuel vapor and combustion air.

The feeding of the liquid, so here the liquid fuel, via a generally designated 34 supply. In the variant shown in FIG. 1, this comprises a line section 36 preferably made of metal, which opens into an opening 38 provided in the bottom wall 20 of the carrier 18 and in this region is also connected to the carrier 18, for example by soldering. In the illustrated example, it can be seen that the carrier 18 in this region of the bottom wall 20, in which the opening 38 is formed for feeding the liquid, in the direction of the porous evaporator medium 24 is bent away and thus an approximately cylindrical and with a free end of the porous Evaporator medium 24 provides a facing connection approach, in which the end of the line section 36 is inserted.

It can be seen further in FIG. 1 that the line section 36 is formed with two regions 40, 42. The region 40 is the region which directly adjoins the carrier 18, while the region 42 lies farther away from the carrier 18. It can be seen that the outer dimension of the line section 36 in the area 40 is significantly lower than in the area 42, while at the same time it is preferably ensured that the inner opening of the line section 36 formed in these areas 40 and 42 has substantially the same cross-sectional area. The essential advantage of such a configuration is that in the region of the connection to the thermal strongly influenced carrier 18 due to the significantly lower wall thickness, a comparatively good thermal decoupling of the line section 36 and thus the feed line 34 is realized. The risk of excessive heating, in particular in the region 40, can thus be significantly reduced, and thus likewise the risk of fuel boiling in the region of this line 40 or directly at the outlet in the region of the opening 38.

In order to produce the most uniform possible fuel entry into the porous evaporator medium 24, the opening provided in the line section 36 may be formed as a capillary, so have a comparatively small cross section, small compared to a line, the line section 36, for example with a metering pump or other conveying member combines. Thus, a stable back pressure is ensured, which brings about a homogenization of the generally pulsed zugefürten liquid flow with it.

Further, since the line section 36 is mechanically less stable due to its partially very thin-walled configuration, it may be advantageous to secure this line section 36 by supporting by means of a Abstützansatzes 44 against compressive and tensile loads.

FIG. 2 shows a detailed view of the evaporator assembly 16 in the region in which a line section 36 of the supply line 34 reaches the carrier 18 or the bottom wall 20 thereof. This may, for example, be the first line region 40 of the previously described embodiment, but may also be another line section 36 formed with substantially the same wall thickness over its entire length.

It can be seen that, in the area surrounding the opening 38 in the carrier 18, the bottom wall 20 of the carrier is initially shaped in the direction away from the porous evaporator medium 24 and thus has a ring-like or bead-like transition region 46 to the then again toward the porous evaporator medium 24 extending to the connecting lug 48 provides. The transition region 46 forms in the transition to the connecting lug 48 a funnel-shaped insertion formation into which the conduit section 36 can be introduced by applying a specific pressing force. Preferably, the line section 36 is introduced so far that it does not protrude beyond the porous evaporator medium 24 facing the free end 50 of the connecting lug 48. The outer dimension of the conduit section 36 may be tuned to the inner dimension of the connection lug 48 to provide a press fit. Furthermore, in the region in which the transition region 46 forms the funnel-shaped introduction formation is preferably by soldering material 52 or other materially acting connection material, such. As adhesive, or by welding a material-locking and thus the connection stability on the one hand and the sealing completion on the other hand supporting connection created.

It can further be seen that not only in the region in which the bottom wall 20 of the carrier 18 is deformed away from the porous evaporator medium 24, no direct physical contact with the porous evaporator medium 24, but that the free end 50 of the connecting lug 48 at a distance of lying facing away from the combustion chamber 14 back of the porous evaporator medium 24 is located. In addition to the high connection stability provided by this type of connection between the support 18 and the supply line 34, the thermal loading of the supply line 34 is also significantly reduced in this embodiment, as these and also the carrier 18 in its associated with the feed line 34 area not is in direct contact with the porous evaporator medium 24, which is exposed on its other side to the very high combustion temperatures. Furthermore, this embodiment has the advantage that by the possibility of the interference fit between the carrier 18 and the line section 36 and Also, the process of further joining by soldering material or the like is facilitated and the risk that such material penetrates into the region in which the porous evaporator medium 24 is provided, can be significantly reduced.

Another variation of such evaporator assembly 16 is shown in FIG. It can be seen here that, which may not necessarily be so, the connecting lug 48 is again shaped so that it is directed away from the porous evaporator medium 24. An introduction element 54 with an approximately cylindrical or pot-like configuration is introduced into the connection attachment 48. In this introduction element 54, an approximately cylindrically shaped porous liquid transfer medium 56 is accommodated, which extends into the area enclosed by the support 18 and is there in direct fluid-transfer contact with the porous evaporator medium 24. Also, the liquid transfer medium 56 is formed of nonwoven material, which ensures by its porosity that the liquid fuel received therein or the other liquid to be transported is transported by Kapillarförderwirkung.

In a region remote from the carrier 18, the inlet element 54 has a channel-like opening 58, which surrounds the porous fluid transmission medium 56 on its outer side and is open to the latter. A line section 36 leads in this area into the inlet element 54 and thus feeds the liquid, for example liquid fuel, into the preferably ring-like circumferential channel 58. In the region of this channel, the liquid then enters the porous liquid transfer medium 56, is guided by this in the direction of the porous evaporator medium 24 and then distributed therein to be evaporated in the direction of the combustion chamber.

Even with such an embodiment, there is a risk of excessive Heating the liquid in the region in which it exits the line, practically not, because here, too, this area is relatively far away from the thermally heavily loaded evaporator medium 24th

It can be seen in Fig. 3 further that the ignition member 32 is arranged so that it passes through the inlet element 54 concentrically and thus is substantially concentric within the liquid transfer medium 56 and to this also has a distance. Preferably, the ignition member 32 extends into that region in which the porous evaporator medium 24 is located or even beyond in the combustion chamber 14. In this arrangement, it is also ensured that the ignition can take place where the first fuel introduction take place is, wherein the porous liquid transfer medium 56 contributes to the fuel evaporation in the surrounded by it and the ignition member 32 receiving volume range, so there is preferred and early an ignitable mixture is formed. The liquid transfer via the porous liquid transfer medium 56 has the further advantage that pulsations in the liquid stream are damped or compensated, so that a clearly uniform liquid flow can be conducted into the porous evaporator medium 24.

In order to reduce the heat interaction even further, it is proposed that the inlet element 54 made of poorly heat conductive material such. As ZrO ₂ with aggregates, or PTFE is constructed. Because of the use of highly thermally insulating materials for the inlet element realized here very good thermal decoupling this embodiment shown in Fig. 3 is particularly suitable in conjunction with very low-boiling fuels, such. Eg PME.

FIG. 4 shows a further modification of an evaporator assembly 16, in which a very good thermal decoupling of the liquid feed line 34 is also realized with a very simple structure. These passes through the opening 38 in the bottom wall 20 of the carrier 18 without contact to this and carries at its end a disc-like support member 60. This thus covers the bottom wall 20 in the area surrounding the opening 38. On the support element 60, a cutting-like or edge-like and ring-like completely circumferential support region 62 is formed, specifically on the side facing the bottom wall 20. Due to the contact with this support region 62 on the bottom wall 20, only a very small heat transfer surface is created on the one hand due to a line-like or edge-like contact, which ensures a correspondingly good thermal decoupling of the support 18, which is generally constructed of sheet metal material and thus has good thermal conductivity. Since in this embodiment, the line 34 by the porous evaporator medium 24, which also presses against the support member 60, biased against the bottom wall 20, a fluid-tight closure of the opening 38 is further ensured.

In the embodiment shown in Fig. 5, which corresponds with respect to the support of the preceding, the biasing force is substantially not or not only generated by the porous evaporator medium 24, but by a spring 64 embedded therein. In this case, preferably, the porous evaporator medium 24 is double-layered with layers 24 'and 24 ", and this spring 64 is arranged in the region which is surrounded by the layer 24' and closer to the carrier 18. The spring 64 then rests against the further layer 24 'of the porous evaporator medium 24 from.

In the variant shown in Fig. 6, the line 34 is in its opening 38 penetrated area significantly widened, which of course also requires a correspondingly larger opening 38. In this expanded area, the support element 60 with the support region 62 is then provided either by integral design or by separate attachment, which is supported again on the support 18. It should be noted here that, as in the embodiments according to FIGS. 4 and 5, here the carrier 18 in its area surrounding the opening 38 a support surface 66 for the support area 62 provides.

The stable abutting contact between the support surface 66 and the support region 62 is ensured here by a spring 64 located outside the support 18. This is supported on the support 18 on the outside where abuts the support region 62 on its inside. In its other end region, the spring 64 is supported on an abutment element 68 fixed to the line 34.

In this embodiment, in the region in which the supply line 34 is widened by providing an attachment part 70 in its region adjoining the porous evaporator medium 24, a volume region 72, preferably filled with porous material, is provided, which forms a fuel reservoir. This material can have a different, preferably greater, porosity than the evaporator medium 24. Thus, a significantly more uniform transfer of this pulsed fuel in the direction of the porous evaporator medium 24 can also be ensured here with pulsed fuel feed.

FIG. 7 shows a variant in which the supply line 34 has a funnel-like or trumpet-like extension in its end region. In this area, the conduit 34 on its outer side provides the support surface 66, on which now an edge 74 of the bottom wall 20 of the support 18 surrounding the opening 38 in the support 18 and providing the support region 62 is supported. The prestressed installation can be ensured here as is the case in the embodiments according to FIGS. 4 to 6, wherein in the variant shown in FIG. 7 the contact pressure force is provided by the locally compressed porous evaporator medium 24 itself.

It should finally be pointed out that preferably in all embodiments described above, the evaporator assembly 16 is constructed so that the porous evaporator medium is connected to the cup or dish-like carrier surface. This can be achieved, for example, by producing a sintered connection or by sintering the porous evaporator medium 24 into the dish-type carrier 18. In any case, the above-described embodiments with a comparatively simple and cost-effective design on the one hand ensure a stable connection to a Flüssigkeitszuführleitung, on the other hand, but also a sufficient thermal decoupling of this feed from the hotter areas, so for example in a burner assembly the thermally heavily loaded porous evaporator medium. Thus, the risk of boiling fuel when leaving the supply and the associated pollution is significantly reduced.

Claims (17)

An evaporator arrangement, in particular for a vehicle heater or a reformer, comprising porous evaporator medium (24) carried on a carrier (18) and a liquid feed line (34) which feeds liquid through an opening (39) in the carrier (18) into the evaporator medium (24 ),
wherein the liquid feed line (34) is formed in a first region (40), which adjoins the carrier (18), with a lesser wall thickness than in a second region (42) located farther from the carrier (18). Evaporator arrangement according to claim 1,
characterized in that an opening cross-section of the liquid supply line (34) in the first region (40) and in the second region (42) is substantially equal. An evaporator arrangement, in particular for a vehicle heater or a reformer, comprising porous evaporator medium (24) carried on a carrier (18) and a liquid feed line (34) which feeds liquid through an opening (38) in the carrier (18) into the evaporator medium (24 ),
wherein on the support (18) a connection projection (48) for the liquid supply line (34) is provided and wherein a free end (50) of the connecting lug (48) is directed towards the porous evaporator medium (24). Evaporator arrangement according to claim 3,
characterized in that the support (18) is deformed away in a region surrounding the connection attachment (46) in the direction away from the porous evaporation medium (24) and in a transition region (46) to the connection attachment (48) a funnel-like Provides introduction formation for the liquid supply line (34). Evaporator arrangement according to claim 4,
characterized in that the liquid supply line (34) in the region of the insertion formation with the support (18) is materially connected. Evaporator arrangement according to claim 5,
characterized in that the material-locking connection is provided by soldering or welding or gluing. Evaporator arrangement according to one of claims 3 to 6,
characterized in that the free end (50) of the connecting lug (48) is spaced from the evaporator medium (24). An evaporator arrangement, in particular for a vehicle heater or a reformer, comprising porous evaporator medium (24) carried on a carrier (18) and a liquid feed line (34) which feeds liquid through an opening (38) in the carrier (18) into the evaporator medium (24 ),
wherein the liquid supply line (34) opens into a distribution channel (58) which surrounds a ring in a manner which surrounds a porous liquid transfer medium (56) and is open to the latter. Evaporator arrangement according to claim 8,
characterized in that the distribution channel (58) is provided in an introduction element (54) receiving the liquid transfer medium (56) and connected to the support (18). Evaporator arrangement according to claim 8 or 9,
characterized in that an ignition member (32) passes through the substantially cylindrically shaped liquid transfer medium (56) at least partially and at a distance. An evaporator arrangement, in particular for a vehicle heater or a reformer, comprising porous evaporator medium (24) carried on a carrier (18) and a liquid feed line (34) which feeds liquid through an opening (38) in the carrier (18) into the evaporator medium (24 ),
wherein an assembly of carrier (18) and liquid supply line (34) is associated with a support surface (66) on which the other of these two assemblies is supported with an edge-like support portion (62). Evaporator arrangement according to claim 11,
characterized in that the support interaction between the support surface (66) and the support portion (62) creates a fluid-tight seal of the opening (38). Evaporator arrangement according to claim 11 or 12,
characterized in that the support region (62) bears under pretension on the support surface (66). Evaporator arrangement according to claim 13,
characterized in that the bias voltage is provided by a spring (64) acting between the carrier (18) and the liquid supply line (34). Evaporator arrangement according to claim 13 or 14,
characterized in that the bias voltage is provided by the porous evaporator medium (24). Evaporator arrangement according to one of claims 11 to 15,
characterized in that at one end portion of the liquid supply line, a the support region (62) exhibiting, disc-like support member (60) is provided. Evaporator arrangement according to one of claims 11 to 15,
characterized in that the liquid supply line (34) provides the support surface (66) in a widening region and the support (18) provides the support region (62) with an edge (74) surrounding the opening (38).

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