Evaporator arrangement

Abstract

An evaporator arrangement for an evaporator burner for a mobile heating device is provided, having: an evaporator body support into which a fuel supply line for supplying a liquid fuel opens, and an evaporator body for distributing and evaporating the liquid fuel. The evaporator body comprises at least one layer of a metal woven fabric of interwoven metal wires.

Claims

1. A vehicle heating device, having: an evaporator burner and a heat exchanger through which hot exhaust gases are routed and in which at least a part of generated heat is transferred to a medium to be heated, the evaporator burner comprising an evaporator arrangement having, an evaporator body support into which a fuel supply line for supplying a liquid fuel opens, and an evaporator body for distributing and evaporating the liquid fuel, wherein the evaporator body comprises at least one layer of a metal woven fabric of interwoven metal wires, wherein the evaporator body comprises a construction with plural layers with at least one layer of a metal non-woven fabric, and wherein the at least one layer of the metal non-woven fabric is arranged at a side of the at least one layer of metal woven fabric which faces away from the fuel supply line.

2. A vehicle heating device according to claim 1, wherein the metal wires comprise stainless steel.

3. A vehicle heating device according to claim 1, wherein the metal wires in the at least one layer comprise a constant wire diameter (d).

4. A vehicle heating device according to claim 1, wherein the metal wires comprise a wire diameter (d) between 25 m and 0.9 mm.

5. A vehicle heating device according to claim 1, wherein the metal wires in the metal woven fabric are tightly interwoven with a relation w/d of a mesh width w to a wire diameter d fulfilling: w/d1.

6. A vehicle heating device according to claim 1, wherein the evaporator body comprises a construction with a plurality of layers of metal woven fabric of interwoven metal wires.

7. A vehicle heating device according to claim 6, wherein at least one first layer of metal woven fabric and a second layer of metal woven fabric are provided, the second layer being arranged at a side of the first layer which faces away from the fuel supply line, and that the second layer is formed from metal wires having a smaller wire diameter (d) than the metal wires in the first layer.

8. A vehicle heating device according to claim 1, wherein the evaporator body comprises a first region for distributing the liquid fuel and a second region for evaporating the liquid fuel, the second region having a structure differing from the structure in the first region.

9. A vehicle heating device according to claim 1, wherein the at least one first layer of metal woven fabric, at least one second layer of metal woven fabric, the second layer being arranged at a side of the first layer facing away from the fuel supply line, and at least one layer of a metal non-woven fabric are provided and that the at least one second layer is formed from metal wires having another wire diameter (d) and/or another mesh width (w) than the metal wires in the at least one first layer.

10. A vehicle heating device according to claim 9, wherein the layer of metal non-woven fabric is arranged at a side of the at least one second layer of metal woven fabric facing away from the fuel supply line.

11. A vehicle heating device according to claim 9, wherein the layer of metal non-woven fabric is arranged between the at least one first layer of metal woven fabric and the at least one second layer of metal woven fabric.

12. A vehicle heating device according to claim 9, wherein the at least one second layer of metal woven fabric is formed from metal wires comprising a larger wire diameter (d) and/or a larger mesh width (w) than the metal wires in the at least one first layer.

13. A vehicle heating device according to claim 1, wherein at least one layer of a metal non-woven fabric is provided which comprises a sintered metal non-woven fabric having a mean fiber length of the metal fibers shorter than 3 mm.

14. A vehicle heating device according to claim 1, wherein at least one layer of a metal non-woven fabric is provided which comprises a sintered metal non-woven fabric having a mean fiber length of the metal fibers shorter than 2 mm.

15. The vehicle heating device according to claim 1, wherein the heat exchanger is adapted such that the heat is transferred to cooling liquid in a cooling liquid circuit.

Description

(1) Further advantages and developments will become apparent from the following description of an embodiment with reference to the drawings.

(2) FIG. 1 schematically shows an evaporator arrangement in an evaporator burner for a mobile heating device.

(3) FIG. 2 is a schematic illustration of the evaporator body.

(4) FIG. 3 is a schematic sketch for explaining the wire diameter and the mesh width in a metal woven fabric.

(5) In the following, an embodiment is described with reference to FIG. 1 and FIG. 2.

(6) In FIG. 1, a region of an evaporator body support 2 and of a burner cap 3 of an evaporator burner for a mobile heating device is schematically illustrated. FIG. 1 is a schematic illustration in a plane containing a main axis Z of the evaporator burner. The evaporator burner can e.g. comprise substantially rotational symmetry with regard to the main axis Z. The evaporator burner can e.g. be formed for a vehicle heating device, in particular for a supplementary heater or for a parking heater. The evaporator burner is in particular formed to convert a mixture of evaporated fuel and combustion air in a combustion space 4 thereby generating heat. The heat which is set free is transferred to a medium to be heated, which can e.g. be formed by air or by a cooling liquid, in a heat exchanger (not shown). In the schematic illustration of FIG. 1, in particular the heat exchanger, the discharge line for the hot combustion exhaust gases, the combustion air conveyor device (e.g. a blower) which is also provided, the fuel conveyor device (e.g. a metering pump), the control unit for controlling the evaporator burner, etc. are not shown. These components are well-known and extensively described in the prior art.

(7) The evaporator burner 1 comprises an evaporator body support 2 in which an absorbent evaporator body 5 is arranged. In the embodiment, the evaporator body support 2 comprises a substantially cup-shaped shape. The evaporator body 5 is accommodated in the cup-like depression of the evaporator body support 2 and can in particularly be fixedly held therein, e.g. by welding, soldering, clamping or using a suitable securing element. The design of the evaporator body 5 will be described more in detail in the following.

(8) A fuel supply line 6 for supplying fuel to the evaporator body 5 is provided. The fuel supply line 6 opens into the evaporator body support 2 and is connected to a fuel conveying device (not shown) by which fuel can be conveyed through the fuel supply line 6 in a predetermined amount, as schematically depicted by arrow B. The fuel supply line 6 is fixedly connected to the evaporator body support 2, e.g. by welding or soldering.

(9) The combustion space 4 is circumferentially bordered by a combustion chamber 7, which can e.g. be formed by a substantially cylindrical component of temperature resistant steel. The combustion chamber 7 is provided with a plurality of holes 7a via which combustion air can be supplied into the combustion space 4, as schematically depicted by arrows in FIG. 1.

(10) The evaporator burner is formed such that in operation liquid fuel can be supplied to the evaporator body 5 via the fuel supply line 6. In the evaporator body 5, on the one hand, distribution of the fuel over the entire width of the evaporator body 5 takes place due to the multitude of cavities and, on the other hand, evaporation of the fuel takes place at the side facing the combustion space 4. In the depicted embodiment, the evaporator body 5 comprises a substantially circular cross-sectional shape in the center of which the main axis Z extends. The evaporator body 5 can however also have other cross-sectional shapes.

(11) The evaporator body 5 comprises a construction with plural layers which is zoned into a first region B1 for distributing the liquid fuel and a second region B2 having a structure differing from the structure in the first region B1 for evaporating the liquid fuel. The first region B1 is arranged facing the fuel supply line 6 and the second region B2 is arranged facing the combustion space 4.

(12) In the depicted embodiment, both the first region B1 and the second region B2 each comprise a plural-layer construction with a plurality of layers. Although schematically three layers are depicted in the first region B1 and schematically five layers are depicted in the second region B2 in the schematic illustration of FIG. 2, the two regions B1, B2 can each comprise more layers or fewer layers. For instance, it is also possible that the first region B1 and/or the second region B2 comprise only one layer. Although the layers in both regions B1, B2 are depicted as being equally thick in each case, the layers in the first region B1 can also have different thicknesses and the layers in the second region B2 can also have different thicknesses. Further, it is also possible that at least one further region is provided in addition to the two regions B1 and B2.

(13) In the depicted embodiment, the layers 8 in the first region B1 are each formed by metal woven fabric of interwoven metal wires. In the embodiment, the layers 9 in the second region B2 can also be formed by metal woven fabric of interwoven metal wires or can also e.g. be formed by a metal non-woven fabric (metal fleece). The layers 8 in the first region B1 can be interconnected, e.g. by sintering or welding. Similarly, the layers 9 in the second region B2 can be interconnected, e.g. by sintering or welding. Further, the layers 8 of the first region B1 can be connected to the layers 9 of the second region B2, e.g. by sintering or welding.

(14) The metal wires in the distinct layers 8 and 9, respectively, are made from a high-temperature resistant stainless steel. In the distinct layers 8 (and 9 in the case that also the layers 9 are formed by a metal woven fabric), the metal wires comprise a uniform wire diameter d, i.e. all the metal wires in the respective layer comprise the same wire diameter d and the distinct metal wires have a constant wire diameter over their length. The metal wires comprise a wire diameter d between 25 m and 0.9 mm. Preferably, the metal wires in the first region B1 comprise a wire diameter d between 100 m and 0.9 mm and the metal wires in the second region comprise a wire diameter d between 25 m and 200 m, preferably between 50 m and 150 m. The respective layers 8 or 9 of metal woven fabric can have changing orientations, e.g. a first layer can have a predetermined orientation of the warp threads and in a subsequent layer the warp threads can be arranged rotated by a predetermined angle with regard to the first layer, and so on. In this way, fuel distribution and fuel evaporation can be selectively influenced.

(15) The metal woven fabric of which the respective layers 8 or 9, which are made of metal woven fabric, are formed is in each case tightly woven such that a relation w/d of the respective mesh width w to the respective wire diameter d fulfills the relation w/d1. The mesh width w is defined by the free distance between two neighboring weft threads or between two neighboring warp threads, respectively, as can be seen in the schematic illustration in FIG. 3. In the depicted embodiment, the wire diameter of the weft threads is identical to the wire diameter of the warp threads and the mesh width in the direction of extension of the weft threads is identical to the mesh width in the direction of extension of the warp threads. Also in the case of different mesh widths in these two directions (which can occur depending on the type of weaving pattern), preferably w/d1 holds for both directions.

(16) As was already described, the layers 9 in the second region B2 or in an additional third region can e.g. also be formed by one or more layers of metal non-woven fabric (metal fleece). In a metal non-woven fabric, pressed andas the case may besintered metal fibers are present which are arranged in an unordered (random) orientation with regard to each other. The distinct metal fibers comprise different lengths and different thicknesses or cross-sectional shapes. Preferably, the metal non-woven fabric can be formed as a thus-called short fiber non-woven fabric (short fiber fleece) having a mean fiber length shorter than 3 mm, preferably shorter than 2 mm, in particular shorter than 1.5 mm.

(17) In the case of a combination of layers formed of metal woven fabric and at least one layer of metal non-woven fabric, the layer of metal non-woven fabric can e.g. be arranged at a side facing away from the fuel supply line 6 (i.e. at a side facing the combustion space) of the layers 8, 9 of metal woven fabric. Alternatively, it is also possible to arrange the at least one layer of metal non-woven fabric between the layers of metal woven fabric 8, 9 such that at least one layer of metal woven fabric is provided at a side facing away from the fuel supply line 6 (i.e. at a side facing the combustion space) of the metal non-woven fabric. In the latter case, the layer of metal woven fabric arranged at the side of the combustion space provides thermal protection and mechanical stability for the at least one layer of metal non-woven fabric and the entire evaporator body 5, respectively.

(18) In a realization with at least two different layers of metal woven fabric and at least one layer of metal non-woven fabric, preferably at least one layer of metal woven fabric can be arranged immediately adjacent to the metal non-woven fabric and preferably fixedly connected to the latter. Preferably, the layer of metal woven fabric adjacent to the metal non-woven fabric can have a larger wire diameter and/or a larger mesh width as compared to layers of metal woven fabric which are arranged closer to the fuel supply line 6.

(19) Although with regard to the embodiment a construction was described which is zoned into a first region B1 for fuel distribution and a second region B2 for fuel evaporation, such a construction is not mandatory and an evaporator body 5 can also be provided which does not comprise such a zoning.