BURNER UNIT

Abstract

Example embodiments relate to a burner unit for combusting an air-fuel mixture. The burner unit includes an air supply dome having recesses which have a larger width on an inside of the air supply dome than on an outside.

Description

FIELD OF DISCLOSURE

The present disclosure relates to a burner unit for combusting an air-fuel mixture.

BACKGROUND

The burner unit is, for example, part of a heater for heating air or a liquid, e.g. water. The fuel is, for example, diesel, gasoline or a combustible gas (e.g. propane).

DE 295 11 384 U1 describes a burner unit having an outer tube and an inner tube. The inner tube is located within the outer tube and allows combustion air to be supplied via slots. The fuel is introduced into the outer tube. The resultant mixture of air and fuel is combusted in a flame tube. The structure of a combustion chamber is further taught in DE 633 304, DE 44 42 425 B4, DE 44 47 986 B4, DE 195 29 994 A1 or DE 10 2013 109 184 A1.

For combustion to be as complete and as low in pollutants as possible, it is required that the air and fuel be mixed as well as possible.

It is therefore the object of the invention to propose a burner unit which allows the air-fuel mixture to be combusted as well as possible.

SUMMARY

The present disclosure achieves the object by a burner unit for combusting an air-fuel mixture, having a combustion space, a combustion air guide dome and a fuel inlet, wherein the combustion air guide dome is located in the combustion space and has recesses, wherein the fuel inlet opens into the combustion space, and wherein the recesses have a larger width on an inside of the combustion air guide dome than on an outside of the air supply dome.

The recesses in the combustion dome, through which the (combustion) air passes from the interior of the dome into the combustion space, do not have a constant width but narrow from the inside to the outside. The view in each case here is in a plane perpendicular to a longitudinal axis of the dome and/or the burner unit. The dome may alternatively also be referred to as an inner tube or inner cylinder. Furthermore, the fuel, that is, e.g. diesel, enters the combustion space via a fuel inlet. It has been found that the narrowing of the recesses improves mixing. This results, for example, in a more homogeneous velocity distribution in the combustion space. Furthermore, pressure losses can be avoided, for example.

The recesses are, for example, in the form of slots along the longitudinal axis. The air enters the interior of the dome via a fan, for example, and from there into the combustion space around the air supply dome. In one configuration, the burner unit is part of a heating system.

One configuration consists in that the recesses taper from the inside to the outside. For example, the side walls of the recesses have an even profile with a constant slope.

One configuration provides that the recesses are configured such that they produce a nozzle effect for air directed out of the combustion air guide dome.

One configuration consists in that the recesses have a substantially constant profile along a longitudinal axis of the air supply dome. For example, the recesses are axially oriented slots. An alternative configuration provides that the recesses change their shape along a longitudinal axis of the air supply dome. The combustion air guide dome may be closed or open on the face side.

In particular, the longitudinal axis of the combustion air guide dome is perpendicular to the direction in which the recesses become narrower from the inside to the outside.

One configuration consists in that the combustion air guide dome has a substantially circular cylindrical shape. The combustion air guide dome may be closed or open on the face side.

One configuration provides that the recesses have different heights along a longitudinal axis of the air supply dome. In this configuration, the recesses have different lengths or extents in the axial direction. An alternative configuration consists in that the recesses have a common height along a longitudinal axis of the air supply dome. In this configuration, the recesses have a common or equal axial extent along the longitudinal axis.

BRIEF DESCRIPTION OF THE DRAWINGS

In detail, there is a multitude of options for configuring and further developing the burner unit according to the invention. In this regard, reference is made, for one thing, to the claims dependent on claim 1 and, for another thing, to the following description of exemplary embodiments in conjunction with the drawings, in which:

FIG. 1 shows a section taken through a schematic representation of the burner unit along the longitudinal axis; and

FIG. 2 shows a section taken through the burner unit perpendicular to the longitudinal axis.

DETAILED DESCRIPTION

FIG. 1 schematically shows a burner unit 1, which is for example part of a heating system. A mixture of a fuel, e.g. gas or diesel, and combustion air is combusted in the burner space 2. Good mixing is required for a combustion which is as effective as possible and which also produces as few pollutants as possible. The combustion air enters the combustion space 2 via the recesses 4 in the combustion air guide dome 3. The recesses 4 are in the form of slots here, which originate from the inner face side of the combustion air guide dome 3 and extend along the longitudinal axis 6 of the burner unit 1 and here also of the combustion air guide dome 3. The shape of the recesses 4 is thus constant in the axial direction and the recesses 4 extend parallel to one another. In the configuration shown, the recesses 4 furthermore have a common height, that is, a common, i.e., equal, axial extent. The combustion air guide dome 4 is a cylinder having a circular base area. The fuel enters the combustion space 2 via a fuel inlet 5.

FIG. 2 shows a section taken through the combustion air guide dome 3 along the longitudinal axis 6. The recesses 4 can be seen, which extend from the inside 30 to the outside 31 and become narrower from the inside to the outside. The width of the recesses 4 is thus greater on the inside 30 than on the outside 31. This results in the effect of a nozzle.

LIST OF REFERENCE NUMBERS

• • 1 burner unit
  • 2 combustion space
  • 3 combustion air guide dome
  • 4 recess
  • 5 fuel inlet
  • 6 longitudinal axis of combustion air guide dome
  • 30 inside of combustion air guide dome
  • 31 outside of combustion air guide dome

Claims

1. A burner unit for combusting an air-fuel mixture, comprising a combustion space, a combustion air guide dome and a fuel inlet,wherein the combustion air guide dome is located in the combustion space and has recesses,wherein the fuel inlet opens into the combustion space, andwherein the recesses have a larger width on an inside of the combustion air guide dome than on an outside of the combustion air guide dome.

2. The burner unit according to claim 1, wherein the recesses taper from the inside to the outside.

3. The burner unit according to claim 1, wherein the recesses are configured such that they produce a nozzle effect for air directed out of the combustion air guide dome.

4. The burner unit according to claim 1, wherein the recesses have a constant profile along a longitudinal axis of the combustion air guide dome-dome.

5. The burner unit according to claim 1, wherein the combustion air guide dome has a circular cylindrical shape.

6. The burner unit according to claim 1, wherein the recesses have a common height along a longitudinal axis of the combustion air guide dome.