CN1386182A - Atomizing burner - Google Patents

Abstract

The invention relates to an atomizing burner, especially for use in an automobile auxiliary heating system, comprising an atomizing nozzle (2) for processing the fuel, an ignition device (29) and a combustion chamber (8). An air conduction device (10, 10') is connected upstream of a nozzle holder (3) of the atomizing nozzle (2) in order to achieve finer atomization of the fuel. Said air conduction device subjects the combustion air streaming into the atomizing nozzle (2) to a swirl.

Description

spray burner

The invention relates to a spray burner, especially used in a car parking heating device, which has a spray nozzle for supplying fuel, an ignition device and a combustion chamber.

In various fields of use, such as in fuel-burning auxiliary heaters of vehicles and in parking heaters, the liquid fuel must be provided, for example, for combustion in a burner and brought into a state suitable for combustion .

A known device, in particular for use in parking heaters or other mobile units, comprises a suction-capable body, such as a fiber web, which is supplied with liquid fuel via a fuel supply line. The fuel introduced into the suction-capable body is vaporized by the introduction of a combustion air flow and can then be ignited by means of, for example, a glow plug.

Despite the advantages of this method of vaporizing liquid fuel, there are disadvantages to this arrangement. In such evaporators used in combustion plants, it takes a considerable time before a usable flame can be formed, which has a disadvantageous effect on the start-up time of burners equipped with such evaporators.

In order to avoid these disadvantages, it is necessary to develop a spray burner which replaces the evaporation device with a spray nozzle. However, it has been found that the spray nozzles used in spray burners do not always produce the required fuel spray.

It is therefore the object of the present invention to provide a spray burner which enables a high-quality fuel spray and a high efficiency of the burner with a fast start-up of the burner and which Can be made and run simply and economically.

According to the invention, for a spray burner of this type, the task is solved by connecting an air-guiding device upstream of the nozzle seat of the spray nozzle, which imparts a swirl to the combustion air flowing into the spray nozzle effect. By swirling the nozzle air, the spray quality and thus the efficiency of the spray burner can be significantly improved, since the velocity of the combustion air or nozzle air increases due to the acting tangential motion component.

Advantageous developments of the invention are given in the dependent claims.

If a Venturi diffuser is arranged downstream of the device, the opening angle of the diffuser increases expediently with increasing turbulence.

In an advantageous configuration, the air-guiding device has swirl vanes which exert a swirling effect on the combustion air flow on its way to the spray nozzles.

It is expedient if the swirl vanes are arranged on a support mounted on the nozzle holder, two swirl vanes each forming a conical channel together with the support and the nozzle holder. By adjusting the angle of the swirl vanes relative to a radial plane, the tangential air component and thus the nozzle air swirl can be adjusted. In this case, the swirl vanes are arranged approximately radially or substantially obliquely towards the radial direction. The swirl vanes can be designed flat or curved in the direction of flow.

According to a further preferred variant, the air-guiding device has a bowl-shaped sleeve, on which an axial borehole and a tangential borehole are formed, and the sleeve is fastened to the nozzle holder, wherein this fastening can be form-locked or The materials are formed in combination. Or the sleeve can be inserted on the nozzle seat.

The axial drilling and the tangential drilling are matched to one another in such a way that the combustion air is subjected to a defined swirling action. In this way, the characteristics of the vortex can be determined by the choice of the size, arrangement and configuration of the tangential and axial boreholes.

The spray nozzle preferably has an inner cross-section with a pressure distribution over its extension which has a relative pressure at least around the outlet of the fuel from the fuel delivery device relative to the pressure acting in the fuel delivery device. The value of the pressure drop. The magnitude of the pressure drop is selected such that fuel is sucked out of the fuel delivery device and sprayed there. The inner cross-section of the spray nozzle is expediently designed as a venturi nozzle.

Other characteristics and advantages of the invention emerge from the description of preferred embodiments with reference to the accompanying drawings. The picture shows:

Fig. 1 shows a preferred embodiment of spray nozzle of the present invention with longitudinal sectional schematic diagram;

Fig. 2 shows the device of guiding air of spray burner shown in Fig. 1 with perspective view;

Fig. 3 shows a second preferred embodiment of the spray nozzle of the present invention with a longitudinal sectional schematic view;

Fig. 4 shows the guide air device of the embodiment shown in Fig. 3 with the transverse sectional schematic view along line A-A in Fig. 3;

FIG. 5 shows another configuration of the air-guiding device in a schematic transverse section as shown in FIG. 4 .

A spray burner, in particular for use in parking heating systems for motor vehicles, comprises (see FIG. 1 ) a spray nozzle 2 with a nozzle seat 3 , a fuel supply 4 for delivering liquid fuel into the spray region 6 of the spray nozzle 2 and a combustion chamber 8 which is surrounded by a heat shield 9 as a peripheral boundary. Adjoined upstream of the nozzle holder 3 of the spray nozzle 2 is an air-guiding device 10 which exerts a swirling effect on the nozzle air flowing into the spray nozzle 2 . In the embodiment shown in FIG. 1, the spray nozzle 2 is formed as a Venturi nozzle, which has an air inflow channel 5 and a spray area 6 widened in the direction of flow, and is fed into the spray nozzle by means of an air-guiding device 10. 2 in which the spray stream flows through. A liquid or fuel delivery device 11 , for example a fuel needle, protrudes into the air inflow channel 5 of the spray nozzle 2 (see also FIG. 2 ), the fuel delivery device 11 having a defined outlet 13 . In this case, the fuel delivery device 11 is preferably situated on the central axis 7 of the air inflow channel 5 and the spray area 6 of the spray nozzle 2 or venturi nozzle.

If the combustion air flow flows through the spray nozzle 2, a pressure distribution is formed in the spray nozzle 2, wherein a high static pressure firstly develops in the air inflow channel 5, which pressure drops in the flow direction towards the spray area 6 and in the Its minimum value is reached at the outlet 13 of the fuel delivery device 11 for the fuel to be sprayed. The fuel delivered from the fuel delivery device 11 to the outlet 13 is split when discharged from the outlet 13 due to the high air velocity there, thereby being sprayed, whereby the fuel delivered from the fuel delivery device 11 to the outlet 13 is sprayed with a way of suction. The fuel delivery device 11 can be a pipe, a fuel needle or a jet nozzle in order to deliver the fuel to be sprayed almost pressure-free into the Venturi nozzle.

Since the spray nozzle 2 in the embodiment of the burner shown in FIG. 1 is subject to high thermal loads, it is preferably made of ceramics. As an interchangeable material with steel, ceramic materials have significant advantages in terms of thermomechanical properties, such as a lower thermal conductivity and a lower coefficient of thermal elongation.

In the embodiment of the spray burner shown in FIG. 1 , the device 10 for guiding the air comprises a support 12 arranged at a distance from the end face 15 of the nozzle holder 3 and formed as a disc, which is connected to the end face 15 of the nozzle holder 3. The end faces 15 together form an annular gap 14 . Swirl vanes 17 are arranged on the support 12 , which face the end face 15 of the nozzle holder 3 and bear against it in the mounted state. The swirl vanes 17 are arranged on the support 12 offset in the radial direction through the center point of the support 12 formed by the fuel delivery device 11 in order to generate a tangential flow component. Two swirl vanes 17 each form a conical channel 19 together with the support 12 and the nozzle seat 3 (see FIG. 2 ). The combustion air flow flowing in through the annular gap 14 is subjected to a swirl effect by the swirl vanes 17 and the conical channels 19 when flowing into the spray nozzle 2 .

In the embodiment shown in FIG. 1 , the heat shield 9 and the combustion chamber 8 have secondary air holes 16 on their bottom, which can be distributed in the region of a ring edge of the bottom of the heat shield 9 . Only two of these secondary air holes 16 are shown by way of example in FIG. 1 . In addition, secondary air holes can also be provided in the side walls or peripheral walls of the heat shield 9 . The heat shield 9 of the combustion chamber 8 is fastened as a separate component to the nozzle holder 3 via a seal 18 and a flange 20 , for example by means of screws 23 . The flange 20 contains a further air-guiding device 21 for swirling the secondary air flowing through the secondary air holes 16 into the combustion chamber 8 . The air-guiding device 21 also contains approximately radially arranged swirl vanes 25 in an annular gap 22, which, in the manner already described, produce a tangential flow component to form swirls.

Furthermore, the spray burner contains a stop in the combustion chamber 8 in the direction of the fuel spray in the flame region, preferably a stop disc 24 which can be conical, convex or concave. In this embodiment, the baffle plate 24 is formed as a bowl-shaped plate with a flange 26 facing the fuel spray direction, wherein the diameter of the baffle plate 24 is smaller than the diameter of the combustion chamber 8, and the diameter of the baffle plate 24 is closely related to the combustion chamber 8. The ratio of the diameters of the chambers 8 is preferably between 0.6 and 0.9. The baffle plate 24 is fixed on the heat shield 9 by means of a fixing piece 28 . The ratio of the axial distance of the baffle plate 24 to the fuel spray point at the outlet 13 of the fuel delivery device 11 to the diameter of the combustion chamber 8 is preferably between 0.3 and 0.6. An ignition device 29 , shown schematically with dashed lines, is used to ignite the sprayed fuel, which is then arranged in the combustion chamber 8 following the venturi nozzle.

A second embodiment of the spray burner (see FIGS. 3 and 4, wherein the same elements as in the first embodiment are indicated by the same reference numerals) comprises a device 10' for guiding air, which has a bowl-shaped The sleeve 30, in the bottom of which forms axial ventilation openings 3, for example axial bores, and in its peripheral wall 33 peripheral ventilation openings 34, which are also called tangential holes due to their orientation. The sleeve 30 is fastened to the nozzle holder 3 of the spray nozzle 2 , for example by being plugged onto the nozzle holder 3 or by another positive, force-transmissible or material-bonded connection. The axial bores 32 and the tangential bores 34 are matched to one another in such a way that the combustion air flowing into the air inflow channel 15 and then into the spray region 16 is subjected to a defined swirl action.

FIG. 4 shows an example of an arrangement of axial vent openings or axial bores 32 and peripheral vent openings or tangential bores 34 in sleeve 30 . By varying the number of openings or bores 32 , 34 as well as their size and arrangement, the swirl of the combustion air flow can be adjusted as desired.

The cup-shaped sleeve 30 shown in FIG. 5 has air openings 35 on its peripheral wall 33 , which are each bounded towards the center of the sleeve 30 by an air guide vane 36 . The incoming combustion air is subjected to a tangential flow component by the air guide vanes 36 .

Obviously, the desired air guiding effect can also be adjusted by combining the individual features of the two embodiments.

Reference Label 2 Spray Spray Together 3 Nozzle 4 Fuel Supply Device 5 Air Flow Entering Channel 6 Spray Area 7 Central Axis 8 Burning Room 9 Heatshield 10 Driven Air Device 10 ′ Driven Air Deng Exit 14 ring gap 15 end surface 16 secondary air 17 vortex blades 18 sealing parts 19 channels 20 flanged device 22 gap between the gap 24 vortex leaves 26 acute edge 28 fixed film 32 axis 32 axis 32 axial direction Drilling hole 33 Perimeter wall 34 Vent 35 Vent 36 Air guide vane

Claims (12)

1. The spray burner, especially used in the car parking heating device, has a spray nozzle (2) for providing fuel, an ignition device and a combustion chamber (8), it is characterized in that, in the spray nozzle (2) An air-guiding device (10, 10') is connected in front of the nozzle seat (3) of the nozzle, which exerts a swirling effect on the combustion air flowing into the spray nozzle (2). 2. The spray burner as claimed in claim 1, characterized in that the air-guiding device (10) has swirl vanes (17). 3. Spray burner according to claim 2, characterized in that the swirl blades (17) are arranged on a support (12) mounted on the nozzle seat (3), and each two swirl blades (17) ) forms a tapered channel (19) together with the support (12) and the nozzle seat (3). 4. Spray burner according to claim 1, characterized in that the air-guiding device (10') has a bowl-shaped sleeve (30) fixed on the nozzle seat (3), and the bowl-shaped sleeve has a Axial vents (32) are formed therein and peripheral vents (34; 35) are formed in a peripheral wall (33). 5. The spray burner as claimed in claim 4, characterized in that the peripheral ventilation openings (34) are boreholes formed tangentially close to the peripheral wall (33). 6. The spray burner as claimed in claim 4 or 5, characterized in that air guide vanes (36) are arranged on the peripheral air openings (35). 7. Spray burner according to one of claims 4 to 6, characterized in that the axial air openings (32) and the peripheral air openings (34; 35) are coordinated with each other in such a way that the combustion air is subjected to a defined swirl action . 8. The spray burner as claimed in one of claims 4 to 7, characterized in that the sleeve (30) is positively connected to the nozzle holder (3). 9. The spray burner as claimed in one of claims 4 to 7, characterized in that the sleeve (30) is integrally connected to the nozzle seat (3). 10. The spray burner as claimed in one of claims 4 to 7, characterized in that the sleeve (30) is inserted on the nozzle holder (3). 11. Spray burner according to one of the preceding claims, characterized in that the spray nozzle (2) has an inner cross section which has a static pressure distribution over its entire extension which is at least close to the fuel The outlet ( 13 ) from the fuel delivery device ( 11 ) has its minimum around it, whereby a high flow velocity is achieved, which causes the fuel to be dragged out of the fuel delivery device ( 11 ) and sprayed. 12. The spray burner as claimed in claim 1, characterized in that the spray nozzle (2) is a venturi nozzle.

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