Patent Application
20240280259
The invention relates to a bright radiator, having a burner, a fan, and a radiant panel that serves as a radiating surface and is provided with flame passage channels, wherein the burner is connected to a fuel gas supply, wherein the fan is set up for supplying combustion air to the burner, wherein the burner is set up for bringing about whole-area glowing of the radiant panel.
In the commercial and industrial sector, infrared radiators are frequently used for heating production and warehousing sites. These radiators produce infrared radiation, which is utilized to produce heat. The advantage of infrared radiators as compared with conventional heating systems is, for one thing, that they give off their heat almost without any loss. For another thing, draft air phenomena, as they occur in the case of conventional combustion systems, are avoided.
Infrared radiators are differentiated as bright radiators and dark radiators. While in the case of dark radiators, the heat is produced by means of combustion of a fuel gas/air mixture in a closed tube, during which combustion the surface of the tube heated by the hot gases produced gives off the heat predominantly as radiation, in the case of bright radiators a fuel gas/air mixture is combusted at the surface of one or more ceramic radiant panels provided for this purpose. Either natural gas or liquefied gas (propane gas or biogas) is used as the fuel gas. The name bright radiator is based on the visible combustion of the fuel gas/air mixture on the ceramic radiant panel, which glows as a result. For this purpose, the ceramic radiant panel has flame pass-through channels arranged parallel to one another, having depressions, frequently conical depressions, produced toward the emission side. During combustion, the flame formation occurs essentially in the depressions, and thereby uniform heating of the side walls of the depressions and of the ridges formed between the depressions takes place. In this regard, the ceramic radiant panel can reach temperatures of 950° C. and more. The waste gases of combustion are given off to the room air. Such bright radiators are described, for example, in EP 2 014 980 A1.
In order to minimize the harmful substances that are formed during combustion of the fuel, a constant effort is made to achieve an optimal, stoichiometric ratio between fuel gas and air, so as to achieve the most complete combustion possible, during which the production of harmful substances is minimized.
In the case of modern bright radiators, very good waste gas values are already achieved, and this result is achieved, among other things, by means of an adaptation of fuel gas and/or air going into the burner. In DE 10 2014 019 766 A1, a bright radiator is furthermore described, in which the calorific value of the fuel gas is determined by means of sensors, and the supply of the combustion air is regulated as a function of the mixture ratio that is optimal for this purpose.
Modern bright radiators have proven themselves in practice and demonstrate a relatively low discharge of harmful substances while simultaneously achieving a high degree of efficacy. The present invention is based on the task of making available a bright radiator having a discharge of harmful substances that is further reduced, while maintaining at least the same degree of efficacy. According to the invention, this task is accomplished by means of the characteristics of the characterizing part of claim 1.
With the invention, a bright radiator is made available that has a degree of efficacy that at least remains the same as compared with the state of the art, and in which the discharge of harmful substances is reduced. Because of the fact that the supply of fuel gas is preferably connected exclusively with a hydrogen source, theoretically no carbonaceous pollutants such as carbon monoxide, carbon dioxide or hydrocarbons are contained in the waste gas, since hydrogen does not contain any carbon.
In a further development of the invention, the hydrogen supply and the fan are configured and oriented in such a manner that the hydrogen flow and the combustion air flow are set at an angle relative to one another, wherein the angle is preferably less than or equal to 90 degrees and greater than or equal to 45 degrees. In this way, good mixing of hydrogen and combustion air is achieved.
In an embodiment of the invention, a reflector is provided, which encloses the radiating surface of the radiant panel and delimits a waste gas space, wherein a combustion air mixing space precedes the burner, which space is connected to a combustion air source and the waste gas space. By means of introducing waste gases into the combustion air, a reduction in oxygen is achieved, and thereby it is possible to lower the flame temperature. Furthermore, a reduction of nitrogen oxide emissions is brought about by means of recirculation of the waste gas.
In a further embodiment of the invention, the waste gas space is connected to the combustion air mixing space by way of an ejector, wherein the driving medium of the ejector is combustion air introduced by means of the fan, and the medium drawn into the combustion air mixing space is waste gas situated in the waste gas space. In this way, a defined ratio of combustion air and waste gas is achieved. Preferably a setting apparatus is provided, by way of which the ratio of the combustion air volume stream to the waste gas volume stream of the ejector, which stream is drawn in, can be set.
In a further development of the invention, the combustion air mixing space is arranged within the fan. In this way, good mixing of combustion air and waste gas is achieved.
In an embodiment of the invention, the hydrogen supply is passed over a distributor panel, in a whole-area manner, which panel is arranged parallel to and at a distance from the radiant panel and delimits a fuel mixing chamber. In this way, uniform mixing of hydrogen and combustion air, over the whole area, is brought about, while simultaneously avoiding flame flashback. In an advantageous manner, the fuel gas supply can also be connected to a hydrogen/combustion air mixture source, wherein the hydrogen concentration in the mixture is supplied above the upper explosion limit, and for this reason the hydrogen/combustion air mixture is not capable of igniting. In this manner, only a very small oxygen content in the combustion air that is introduced into the mixing chamber is required.
In a further embodiment of the invention, an incoming air channel that surrounds the distributor panel, at least in part, is provided, which channel is connected to the fan. Preferably the incoming air channel is configured in such a manner that a whole-area flow of combustion air over the distributor panel is brought about. In this way, uniform mixing with the hydrogen that flows through the distributor panel is achieved.
In a further development of the invention, an optical sensor is provided, which is set up for detecting at least one parameter of the flame produced by the burner. It is advantageous if the sensor is a UV sensor. In this way, flame detection of the invisible hydrogen flame is achieved.
In an embodiment of the invention, the optical sensor is directed at the radiant panel so that it preferably encloses the panel at an obtuse angle. In this way, reliable flame detection is achieved.
In a further embodiment of the invention, a reflector that encloses the radiant panel at least in certain regions is provided, the reflector being provided with a window, wherein the optical sensor is oriented toward the radiant panel, from outside of the reflector, through the window. In this way, flame detection in a position of the sensor that is protected from heat is achieved.
In a further development of the invention, the optical sensor is connected to a setting device connected to the fan, for interrupting and/or setting the combustion air supply. Preferably the optical sensor is connected to a setting device connected to the fuel gas supply, for interrupting and/or setting the hydrogen supply. In this way, it is made possible to influence the combustion air/hydrogen mixture or also to shut off the hydrogen supply as a function of the flame status.
In an embodiment of the invention, the setting device is connected to a control and regulation module that is programmed for regulating the flame properties on the basis of reference parameters stored in memory, by means of changing the amounts of hydrogen and/or combustion air.
Other further developments and embodiments of the invention are indicated in the other dependent claims. Exemplary embodiments of the invention are shown in the drawings and will be described in detail below. The figures show:
The bright radiator according to
The burner 1 comprises a fuel mixing chamber 11, which is delimited by a ceramic radiant panel 12. The ceramic radiant panel 12 is provided, in a known manner, with a perforated pattern that extends over the entire surface area, which pattern is formed by cylindrical flame passage channels that are configured to widen conically on the side of the radiant panel 12 that is directed outward. Lying opposite the radiant panel 12, a hydrogen supply 2 is arranged, orthogonal to it, which supply empties into the fuel mixing chamber 11. At a right angle to the hydrogen supply 2, a pressure line 31 empties into the fuel mixing chamber 11, which is connected to the fan 3.
On its suction side, the fan 3 is connected to an ejector 32, the drive connector of which is connected to a combustion air supply 33, and the suction connector of which is connected to a waste gas supply line 34, which is passed through the reflector. A recirculation orifice 35 is arranged in the waste gas supply line 34. The combustion air stream drawn in by the fan 3 through the combustion air supply 33 serves as a driving medium here, by means of which medium intake of part of the waste gas cushion 381 present within the reflector 4 is brought about through the recirculation orifice 35. The proportion of the waste gas stream in the combustion air stream can be adjusted by means of the recirculation orifice 35, and thereby, in turn, the oxygen content of the waste gas/combustion air stream mixture is determined. The remaining waste gas stream flows out of the reflector 4 into the ambient air. A combustion air mixing space 39 is integrated into the fan 3.
On the pressure side, a waste gas/combustion air mixture is supplied to the fuel mixing chamber 11 by means of the fan 3, which mixture is ignited, together with the hydrogen stream that is introduced by means of the hydrogen supply 2, after exiting through the radiant panel 12, by means of an/the ignition electrode 13 arranged on the burner 1, on the outside, ahead of the radiant panel 12, and thereby a flame carpet is produced on the outside, on the radiant panel 12. The combustion essentially takes place in the conically widened sections of the flame passage channels of the radiant panel 12, and thereby these are heated on the outer surface, until they glow bright red. The flame temperature can be regulated by means of the oxygen content of the waste gas/combustion air mixture, which content can be adjusted by way of the recirculation orifice 35.
In the exemplary embodiment according to
A waste gas stream 38 is drawn in by means of the combustion air stream introduced into the pressure line 31 by way of the fan 3, by way of the suction gap 37, from the waste gas cushion 381 formed within the reflector 4, which stream mixes with the combustion air stream. The waste gas/combustion air mixture that exits from the combustion air mixing space 37 of the pressure line 31 is mixed with the hydrogen stream introduced by means of the hydrogen supply 2, in the fuel mixing chamber 11, and, once again after exiting through the radiant panel 12, is ignited by means of a/the ignition electrode 13 arranged on the burner 1, on the outside, ahead of the radiant panel 12.
In the exemplary embodiment according to
In the exemplary embodiment according to
Between the distributor panel 53 and the radiant panel 52, an intake air channel 54 is provided, enclosing the fuel mixing chamber 51, the jets 55 of which channel are oriented in an imaginary plane set parallel to the distributor panel 53. The intake air channel 54 is connected to the fan 3, by which it is supplied.
The fan 3 is connected, on its suction side, with an ejector 32, in accordance with the first exemplary embodiment, the drive connector of which ejector is connected to a combustion air supply 33, and the suction connector of which ejector is connected to a waste gas supply line 34, which is passed through the reflector 4. A recirculation orifice 35 is arranged in the waste gas supply line 34. The combustion air drawn in by the fan 3, through the combustion air supply 33, once again serves as a drive medium here, by means of which medium part of the waste gas cushion 381 situated within the reflector 4 is drawn in. Here, the proportion of the waste gas stream in the combustion air stream can also be adjusted by means of the recirculation orifice 35, and thereby, in turn, the oxygen content of the waste gas/combustion air stream mixture is determined. The remaining waste gas stream flows out of the reflector 4 into the ambient air. Here, too, the combustion air mixing space 39 is integrated into the fan 3.
On the pressure side, a waste gas/combustion air mixture is supplied to the fuel mixing chamber 51 by means of the fan 3, by way of the intake air channel 54, which mixture flows over the whole area of the distributor panel 53 and mixes with the hydrogen that flows through the distributor panel 53, before it is ignited by an ignition electrode 13 arranged in the fuel mixing chamber 51. The hot combustion waste gas flows through the channels of the radiant panel 52 and thereby brings them to the required temperature.
The distributor panel 53 is cooled by means of the whole-area waste gas/combustion air mixture flow produced by means of the intake air channel 54 over the distributor panel 53, and thereby a flame flashback through the distributor panel 53 is prevented.
| Number | Date | Country | Kind |
|---|---|---|---|
| 21213687.3 | Dec 2021 | EP | regional |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/EP2022/084658 | 12/6/2022 | WO |
