JP2008520948A - Heater burner with improved baffle plate - Google Patents

Abstract

The present invention relates to a heater burner, particularly for use in a motor vehicle, comprising a substantially axially symmetric combustion chamber (22) and a baffle plate (36) arranged in the combustion chamber (22). In accordance with the present invention, the baffle plate (36) has a preset bend in the axial direction, and this bend is provided towards the burnout region (32).

Description

  The present invention relates to a heater burner, particularly for use in a motor vehicle, comprising a combustion chamber that is substantially axially symmetric and a baffle plate disposed in the combustion chamber.

  Such burners, also referred to as spray burners or spray burners, are used in particular in automotive auxiliary heaters and independent heaters.

  There are a number of requirements for such heaters, particularly those that are reliable and have low emissions of hazardous materials and requirements for stable combustion. Furthermore, efforts can be made to make heaters that can be used in different built-in postures.

  For start-up, various operating parameters must be harmonized with one another. On the one hand, during the start of the burner, it is necessary to supply a relatively rich fuel-air-air mixture in the starting area, and on the other hand, a sufficient amount of primary to guarantee fuel transfer from the fuel needle to the starting area. It is necessary to supply combustion air.

  The requirement to allow different built-in postures of the heater is associated with problems with startability. That is, in order to reduce the primary air supply and allow the fuel to be transported to the starting area, conventionally, the outlet of the fuel needle has to be directed downward, thereby mounting the entire burner in a vertically assembled position. There wasn't.

  In order to ensure stable combustion of the burner, sometimes conflicting requirements must be met. On the one hand, good mixing of fuel and air is always required, and on the other hand, it is undesirable to produce too high a proportion of air and too strong vortices in the central area of the flame and especially during the starting phase.

  The problem underlying the present invention overcomes the above-mentioned problems of the prior art at least in part and enables a particularly reliable start-up with less harmful substances emission or less black smoke, with different built-in postures That is.

  This problem is solved by the features of the independent claims.

  Advantageous embodiments of the invention are described in the dependent claims.

  In the present invention, in the burner described at the beginning, the baffle plate has a preset bend in the axial direction, and this bend is provided toward the burnout region. Based on the bending of the baffle plate, a predetermined shape of the baffle plate that does not depend on temperature occurs. In the case of prior art baffle plates formed flat, this was sometimes not achieved. This is because a spontaneous shape change occurs depending on the temperature, which adversely affects the combustion state of the burner. Bending towards the burnout area provides sufficient space for the start-up chamber. Furthermore, it has been found that bending towards the burnout area does not adversely affect the flow conditions in this area. In particular, a clear vortexed counter flow region is maintained radially inward of the burn-out region.

  In an advantageous embodiment of the invention, the outer periphery of the baffle plate defines a plane and the ratio of the maximum axial distance of the baffle plate from this plane to the diameter of the baffle plate is 0.07 to 0.21. is there. The location of the outermost bent baffle plate is preferably about the center of the arrangement with respect to radial coordinates. This location has an axial spacing defined by the above ratio to diameter from a plane defined by the outer periphery of the baffle plate.

  In this connection, it is particularly advantageous if the ratio of the maximum axial distance of the baffle plate from the plane to the diameter of the baffle plate is about 0.14. For example, the baffle plate has a fractional diameter of about 40 mm while the bend has a value of about 5.7 mm.

  In a very advantageous embodiment of the invention, a heat shield with a burner nozzle for supplying fuel and primary air, which is arranged between the burner nozzle and the combustion chamber and has a hole for supplying secondary air to the combustion chamber. A plate is provided and the hole is provided with an air guiding element. The heat shield is basically effective for shielding the nozzle and the fuel supply unit from the thermal energy in the fuel chamber. Further, secondary air is supplied to the combustion chamber through the heat shield. Since the hole for the secondary air supply is equipped with an air guide element, this secondary air supply can be performed properly, so that both the starting operation and the continuous operation are appropriately affected. be able to.

  It is advantageous if the air guiding element is formed by an ear metal that projects towards the combustion chamber and is formed integrally with the heat shield. Such a heat shield plate can be easily manufactured by molding an ear metal with, for example, a v-shaped drilling tool. The ear metal is bent out of the surface of the heat shield after the drilling process or by the drilling process.

  In accordance with an embodiment of the invention, it is advantageous if the ear metal is formed at different angles with respect to the surface of the heat shield and / or with respect to the radial direction of the heat shield. If the ear plate extends almost perpendicular to the radial direction of the heat shield, this ear plate adds a large angular momentum, while the ear plate makes a small angle with respect to the radial direction of the heat shield. A small angular momentum is added. In the case of an ear metal that forms a small angle with respect to the surface of the heat shield, it generates an air flow having a large radial component and a small axial component, while it forms an angle with respect to the surface of the heat shield. Has a large axial component. Thereby, the secondary air having a small angular momentum can be guided to the center range of the flame. Therefore, on the one hand, the air necessary for combustion is supplied. However, excessive angular momentum that adversely affects flame stabilization does not occur. In particular, depending on the direction of the individual air guiding elements, the distribution of secondary air can be performed.

  In other embodiments, the ear metal is grouped and formed at approximately the same angle with respect to the surface of the heat shield and / or with respect to the radial direction of the heat shield. By orienting the ear metall in groups, a defined flow condition occurs in the combustion chamber.

  Further in accordance with an embodiment of the present invention, it is advantageous if the burner comprises a burn-out area, and the secondary air supplied to the burn-out area has a greater angular momentum than the secondary air supplied to the start-up area. A large angular momentum is desired in the burnout region. In particular, the swirled backflow region located radially inward improves burnout and effectively utilizes the combustion chamber volume.

  Furthermore, the heat shield plate is provided with a hole for penetrating and guiding the ignition element.

  In a very advantageous embodiment of the invention, the burner nozzle comprises a fuel needle for supplying fuel to the burner and a primary air supply for supplying combustion air to the burner, by selecting the inner diameter of the fuel needle, The fuel outflow rate is predetermined so that the fuel reaches the start-up region in a substantially non-atomized form during the start-up phase of the burner. By reducing the inner diameter of the fuel needle as compared with the fuel needle of the heater of the prior art, the fuel outflow speed is increased in the case of the same fuel conveyance amount. As a result, the fuel jet from the outlet of the fuel needle can reach the starting region in any built-in posture. In particular, when the amount of primary air is small and the angular momentum of the supplied primary air is small, a fuel jet that is not substantially atomized can reach the starting region. Therefore, the burner is reliably started and the generation of black smoke during the start is remarkably reduced.

  Advantageously, the inner diameter of the fuel needle is between 0.5 and 0.7 mm. Compared to the outflow speed of the prior art fuel needle having an inner diameter in the range of 0.8 mm, the outflow speed in the case of the inner diameter of 0.5 to 0.7 mm is almost twice or more than twice.

  It is very advantageous if the inner diameter of the fuel needle is about 0.6 mm. In the case of such an inner diameter, at full load operation, that is, when the fuel flow rate is 0.5 kg / h, an outflow speed of 0.6 m / s or more is possible, whereas when the inner diameter is 0.8 mm, the outflow speed is The range is 0.35 m / s. In partial load operation, i.e., when the fuel flow rate is 0.2 kg / h, the outflow speed is increased from about 0.14 m / s to about 0.25 m / s. With the proper selection of structural characteristics or operating parameters, the objective of a substantially non-atomized jet that reaches the starting area when the heater is started can be achieved with a conventional fuel needle having an inner diameter of about 0.8 mm.

  It is advantageous if the starting area is formed as a starting chamber and the ignition element is inserted in this starting chamber. Thereby, the wall of the combustion chamber can surround the ignition element. During start-up operation, the “ballistic” fuel jet wets the ignition element and the combustion chamber wall with fuel so that the combustion chamber wall and adjacent components act as wall vaporizers after being warmed.

  The present invention is based on the recognition that the operating state of the burner can be largely perfected by a new bent baffle plate, especially in combination with a new fuel supply and a new heat shield. This relates in particular to the starting conditions, the stability of the burner operation and the possibility of the burner's built-in attitude in the car.

  The invention will be described by way of example on the basis of advantageous embodiments with reference to the accompanying drawings.

  In the following description of the preferred embodiments of the invention, the same reference signs refer to the same or similar components.

  FIG. 1 is a sectional view of a burner according to the present invention. The burner 10 according to the present invention includes a nozzle 12 fixedly connected to a heat shield plate 24. The heat shield plate 24 forms a combustion chamber 22 together with the burner tube 40 connected thereto. The combustion chamber tube 40 is surrounded by an outer tube 42 that forms a burner flange. A flame tube 38 is fixed to the outer tube 42. The connection between the heat shield plate 24 and the combustion chamber tube 40 or the connection between the combustion chamber tube 40, the outer tube 42 and the flame tube 38 is generally a welding connection. A fuel supply unit 50 is disposed in the fuel nozzle 12. The fuel supply unit includes a metal pipe 52 for supplying fuel and a fuel needle 14 for injecting fuel into the combustion chamber 22. Further, a passage for supplying primary combustion air to the fuel nozzle 20 is provided in the range of the fuel nozzle 16. This primary combustion air flows in the vicinity of the fuel needle 14. Thereby, it flows along the air guide of the fuel nozzle 12 extending in the radial direction towards the combustion chamber and finally into the combustion chamber 22. The radial spread of the air guide improves the spraying based on the venturi effect. A baffle plate 36 having an advantageous bend is also arranged in the combustion chamber 22. This bending towards the burnout area 32 is advantageous. This is because the bending prevents the spontaneous shape change of the baffle plate 36 caused by heat. The bending of the baffle plate 36 towards the burnout area 32 further provides sufficient space for installation of the starter chamber 18. The wall defining the starter chamber 18 is welded to the baffle plate 36.

  FIG. 2 is a perspective view of a burner flange into which a heat shield plate is inserted, and FIG. 3 is a perspective view of the heat shield plate. In the following, reference is also made to the components of the burner of FIG. The heat shield plate 24 has a central hole 48, and the mixture of fuel and air supplied from the nozzle 12 flows into the combustion chamber through the hole 48. Furthermore, the hole 34 for letting the ignition element 20 pass is arrange | positioned at the side. The heat shield plate 24 is further provided with fixing pins 44 and 46. The nozzle 12 is fixed to the fixing pins 44 and 46. The heat shield 24 further has a number of holes 26. Secondary air can flow into the combustion chamber 22 through this hole 26. On the side of the heat shield 24 close to the combustion chamber 22, triangular air guide elements 28 and 29 are provided. Since the air guide elements 28 and 29 are at different angles with respect to the radial direction of the heat shield 24, secondary air distribution occurs. The first group of air guide elements (a part of which is denoted by reference numeral 28) is at a large angle with respect to the radial direction of the heat shield 24. That is, the orientation of the air guide element is almost or almost tangential. The secondary air passing through the hole 26 indicated by the arrow in the outflow direction passes through the vicinity of the baffle plate 36 with a large angular momentum based on the direction of the air guide element and flows into the burnout region 32. This air with a large angular momentum flows into the rear region of the combustion chamber 22 in the radially outer region of the burn-out region 32, i.e. into the region of the combustion chamber 22 opposite to the heat shield 24 and forms a large vortex. However, it returns to the baffle plate 36 in the central range. Therefore, the gas component is well mixed in the burnout region 32. The orientation of the other groups of air guide elements 30 is at a small angle with respect to the radial direction of the heat shield 24. This air guide element is indicated in part by reference numeral 30. The air guide element 30 is further at a smaller angle than the air guide element 28 with respect to the surface of the heat shield 24. Therefore, the secondary air whose flow direction is indicated by another arrow is guided to the center range of the flame through the air guide element 30 with a small angular momentum. This promotes particularly stable combustion.

  This provides a new spray burner. This burner is improved with respect to built-in position, start-up condition and continuous operation condition. Furthermore, the problem of baffle plate shape change due to temperature is avoided.

  The features of the invention disclosed in the drawings, in the claims and in the claims are important for realizing the invention either alone or in any combination.

It is sectional drawing of the burner by this invention. It is a perspective view of the burner flange which inserted the heat shield. It is a perspective view of a heat shield.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 ... Burner, 12 ... Burner nozzle, 14 ... Fuel needle, 16 ... Combustion air supply part, 18 ... Starting area, 20 ... Ignition element, 22 ... Combustion chamber, 24 ... Heat shield, 26 ... Hole, 28 ... Air guide element , 30 ... Air guide element, 32 ... Burnout area, 34 ... Hole, 36 ... Baffle plate, 38 ... Flame pipe, 40 ... Burner pipe, 42 ... Outer pipe, 44 ... Fixed pin, 46 ... Fixed pin, 48 ... Hole, 50 ... Fuel supply part, 52 ... Metal pipe

Claims (13)

A substantially axisymmetric combustion chamber (22);
A baffle plate (36) disposed in the combustion chamber (22);
In a burner for a heater, particularly for use in an automobile,
The baffle plate (36) has a preset bend in the axial direction; and
Burner characterized in that this bend is provided towards the burnout area (32). The outer periphery of the baffle plate defines one plane;
2. The burner according to claim 1, wherein a ratio of a maximum axial distance of the baffle plate from the plane and a diameter of the baffle plate is 0.07 to 0.21. 3.   A burner according to claim 2, characterized in that the ratio of the maximum axial distance of the baffle plate (36) from the plane to the diameter of the baffle plate (36) is about 0.14. A burner nozzle (12) for supplying fuel and primary air is provided;
A heat shield (24) disposed between the burner nozzle (12) and the combustion chamber (22) and having a hole for supplying secondary air to the combustion chamber;
The holes are provided with air guiding elements (28, 30);
The burner as described in any one of Claims 1-3 characterized by these.   5. A burner according to claim 4, characterized in that the air guiding element (28, 30) is formed by an ear metal which projects towards the combustion chamber (22) and is formed integrally with the heat shield (24).   6. The ear metal (28, 30) is formed at different angles with respect to the surface of the heat shield (24) and / or with respect to the radial direction of the heat shield. Burner.   The ear metal (28, 30) is formed in a group and is formed at substantially the same angle with respect to the surface of the heat shield (24) and / or with respect to the radial direction of the heat shield. Item 7. The burner according to any one of Items 4 to 6. The burner (10) has a start-up area (18) and a burn-out area (32);
The burner according to any one of claims 4 to 7, wherein the secondary air supplied to the burn-out area has a larger angular momentum than the secondary air supplied to the start-up area.   9. Burner according to any one of claims 4 to 8, characterized in that the heat shield (24) is provided with holes (34) for guiding the ignition element (20) through. The burner nozzle (12) comprises a fuel needle (14) for supplying fuel to the burner (10) and a primary combustion air supply for supplying combustion air to the burner;
By selecting the inner diameter of the fuel needle (14), the fuel outflow rate is predetermined so that the fuel reaches the start region (18) in a substantially unatomized form during the start phase of the burner. The burner as described in any one of Claims 4-9 characterized by the above-mentioned.   13. A burner according to claim 12, characterized in that the inner diameter of the fuel needle (14) is between 0.5 and 0.7 mm.   12. Burner according to one of claims 10 or 11, characterized in that the inner diameter of the fuel needle (14) is about 0.6 mm.   13. Burner according to claims 10-12, characterized in that the starting area (18) is formed as a starting chamber and an ignition element (20) is inserted into the starting chamber.

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