Infrared emitter, heating device and method for controlling the combustion air ratio of an infrared emitter of a heating device

Abstract

The invention relates to an infrared emitter (101, 201, 301, 401) comprising an incandescent element (2), a gas-permeable burner plate (3), a housing (4), a combustion chamber (5) suitable for burning a gas composition, wherein the combustion chamber (5) is at least partially delimited by the incandescent element (2), the burner plate (3) and the housing (4), and also comprising a mixing chamber (6) suitable for mixing a gaseous fuel and air to form the gas composition, wherein the mixing chamber (6) is separated from the combustion chamber (5) by the burner plate (3). The invention also relates to a heating device having a corresponding infrared emitter and to a method for controlling the combustion air ratio of a combustion in a combustion chamber (5) of such an infrared emitter.

Description

[0001] Infrared radiator, heating device and method for controlling the combustion air ratio of an infrared radiator or heating device

[0002] The invention relates to an infrared heater comprising a glowing element, a gas-permeable burner plate, a housing, a combustion chamber suitable for burning a gas composition, wherein the combustion chamber is at least partially delimited by the glowing element, the burner plate, and the housing, and a mixing chamber suitable for mixing a gaseous fuel and air to form the gas composition, which is separated from the combustion chamber by the burner plate. The invention further relates to a corresponding heating device and a method for controlling the combustion air ratio of at least one infrared heater of a heating device.

[0003] Infrared heaters are technical devices that emit infrared radiation and can be used, for example, for heating or drying purposes. Energy sources for infrared heaters are typically electricity or flammable gas. In gas-powered infrared heaters, the operating principle is based on the conversion of the chemically bound energy of the fuel into radiant heat.

[0004] Infrared emitters can be designed, for example, as surface infrared emitters and used in drying systems for drying fibrous webs, such as paper or cardboard. Due to their ability to operate at temperatures above 1100°C, their high specific power density, and their long service life, infrared emitters are particularly suitable for drying web-like materials at high speeds. A preferred application is, for example, the drying of moving paper or cardboard webs in paper mills, such as downstream of coating units.

[0005] Infrared heaters are typically connected to an air supply and a fuel supply line for their operating fluids. In the mixing chamber of the infrared heater, the supplied operating fluids combine to form an ignitable gas mixture, i.e., a gas-air mixture, which then passes through the burner plate into the combustion chamber and is ignited there. The combustion heats the incandescent element, particularly through the hot exhaust gases, which then emits heat in the form of radiation with a high power density.

[0006] An important parameter of combustion is the air-fuel ratio, also known as the air-fuel ratio. The air-fuel ratio influences, for example, the radiant efficiency, the lifespan of the infrared emitter, and the pollutants produced during combustion. To achieve efficient and low-emission combustion, it is desirable to allow combustion to proceed at an optimal air-fuel ratio. Therefore, precise and, in particular, continuous measurement of the air-fuel ratio is necessary. Within the scope of the invention, continuous measurement is intended to include not only ongoing measurements but also, in particular, repeated measurements at predetermined, regular time intervals. Furthermore, embodiments are also included in which measurements can be taken at individually selectable time intervals.The term "continuous" refers to the ongoing possibility of being able to measure the current combustion air ratio at any time without further preparation.

[0007] Continuous measurement of the air-fuel ratio is not possible with conventional infrared emitters. Instead, indirect methods are used to determine the air-fuel ratio. This indirect determination typically involves measuring the pressure in the air and fuel supply lines. The pressures in these lines are measured, and these measurements are then reproduced, particularly at a later time, on a laboratory test bench to determine the supplied gas and air volume flow, from which the air-fuel ratio can be calculated.

[0008] The indirect determination of the air-fuel ratio is subject to high uncertainty due to fluctuating gas compositions, the multiplication of measurement errors from different measuring devices, and varying tolerances of the infrared emitter(s) and test bench. Furthermore, laboratory measurements are subject to a significant time lag, thus precluding continuous measurement of the air-fuel ratio during combustion.

[0009] In practice, the direct measurement of the combustion air ratio using a mobile exhaust gas analyzer is also known. Here, the operator manually holds the mobile exhaust gas analyzer against the outside of the heating element of the infrared emitter and extracts the exhaust gases present there. However, a disadvantage is that the mobile exhaust gas analyzer must be cooled due to the high temperatures of the exhaust gases, and the system in question must be shut down because of the manual measurement. Finally, this method cannot guarantee that no ambient air, i.e., air from the surroundings of the infrared emitter, is drawn in along with the exhaust gases, which would distort the measurement result.

[0010] The object of the invention is therefore to overcome the aforementioned disadvantages and to provide an infrared emitter by means of which a precise and, in particular, continuous measurement of the combustion air ratio is possible.

[0011] To solve this problem, an infrared emitter is proposed comprising a mantle, a gas-permeable burner plate, a housing, and a combustion chamber suitable for burning a gas composition, the combustion chamber being at least partially delimited by the mantle, the burner plate, and the housing. The infrared emitter further includes a mixing chamber suitable for blending a gaseous fuel and air to form the gas composition, the mixing chamber being separated from the combustion chamber by the burner plate. The combustion chamber is connected to an extraction line, with an extraction opening of the extraction line positioned within the combustion chamber such that the gas composition can be extracted from the combustion chamber through this opening.

[0012] In an infrared emitter according to the invention, the gas composition in the combustion chamber can be extracted directly from the combustion chamber. Extracting the gas composition directly from the combustion chamber offers several advantages. Firstly, it ensures that no false air is extracted, which could distort the measurement results. Secondly, the gas composition can be extracted at any time during operation of the infrared emitter. Furthermore, the extraction line and downstream measuring and / or sensor devices do not need to be cooled, since the gas composition is extracted on the cold side of the infrared emitter and therefore has a significantly lower temperature.

[0013] The incandescent element can be formed, for example, from individual rods or from a rectangular structure woven from individual rods. Such rods can be made of metal, particularly steel. The burner plate can consist, for example, of a perforated ceramic plate or a nozzle plate made of a porous nonwoven material. The burner plate can also serve as an additional incandescent element. The housing can comprise several side walls and, for example, be designed with at least one taper. In such a design, the mixing chamber can be located at one end of the housing where a taper may be present, and the combustion chamber can be located at the end of the housing opposite the taper. The housing can be formed, for example, from a metallic mounting frame and sheet metal.The housing can also be made of a surrounding sheet metal, for example of steel or stainless steel. The housing encloses the combustion chamber, burner plate, and mixing chamber, at least partially, whereby the mantle can seal an opening in the housing, allowing air to pass through. The mantle can also at least partially delimit the combustion chamber. In particular, the housing may only partially enclose the combustion chamber.

[0014] The gas composition can, for example, include a mixture of air and a gaseous fuel. The gaseous fuel can include, for example, propane, butane, or natural gas. The gas composition is characterized in particular by its air-fuel ratio. The air-fuel ratio, also known as the air-fuel ratio, is a parameter that indicates the mass ratio of air to fuel. This parameter allows conclusions to be drawn about the combustion process, temperatures, pollutant formation, and combustion efficiency.

[0015] The extraction line can, for example, be designed as a pipe and comprise at least some sections of steel or stainless steel. It is also possible for the extraction line to be designed as a hose, made of a material that is particularly heat-resistant in sections, comprising, for example, polyurethane, polyvinyl chloride, or polyester. The extraction line can be arranged at least partially inside and / or outside the housing. The extraction line can, in particular, be permanently connected to the housing, for example, by welding. It can, in particular, pass through a side wall of the housing so that the extraction opening of the extraction line is arranged in the housing in such a way that the gas composition can be extracted from the combustion chamber through the extraction opening. The extraction opening is thus an opening in the extraction line and can be completely open or, for example, fitted with an air-permeable filter or screen.The extraction opening can, for example, be one end of an extraction line, which is designed, in particular, as a pipe made of steel or stainless steel. The extraction opening, or the extraction line with its attached extraction opening, can, for example, project into the combustion chamber, in which case at least part of a circumferential wall of the extraction line is also located within the combustion chamber. It is also possible that the extraction opening is flush with a component of the infrared emitter that delimits the combustion chamber, for example, with a side wall of the housing, and that the extraction line does not project into the combustion chamber. Furthermore, an infrared emitter can, for example, include an igniter. Such an igniter can, for example, be located in the combustion chamber and designed to ignite the gas mixture.

[0016] In one embodiment of the infrared emitter, the extraction line is routed at least partially through a recess in a side wall of the housing to the combustion chamber. This design has the advantage that the extraction line can be routed at least partially or largely outside the housing, thus eliminating the need for internal space and making damage to the extraction line, for example, visible from the outside. The extraction opening can then be, for instance, flush with the recess in a side wall of the combustion chamber. In this respect, the extraction line can be located on the outside of the housing up to the level of the combustion chamber and then pass through a side wall of the housing into the interior at the level of the combustion chamber. Furthermore, the extraction line and the housing can be sealed from each other using a heat-insulating and / or fluid-tight material.The extraction line and the housing can also be connected to each other, for example around the entire circumference, at the recess, particularly by means of a material bond, for example by welding or soldering.

[0017] In one embodiment of the infrared heater, the extraction line is guided at least partially through a recess in the burner plate to the combustion chamber. With this design, the extraction line can be routed behind the burner plate inside the housing. The extraction line can also protrude at least partially into the combustion chamber through the recess in the burner plate. It is also possible for the extraction opening in the combustion chamber to be flush with the burner plate, with the wall of the extraction line not protruding into the combustion chamber. Furthermore, the extraction line and the burner plate can be sealed from each other using a heat-insulating and / or fluid-tight material. It is also possible for the extraction line to be routed through a side wall of the housing. In this case, the extraction line can, for example, be guided at least partially within a recess in the side wall of the housing.For example, the extraction line can be routed through a side wall of the housing from outside the housing into the interior of the housing, for example into the mixing chamber, and through a recess in the burner plate into the combustion chamber, so that the gas composition can be extracted from the combustion chamber through the extraction opening.

[0018] In one version of the infrared emitter, the suction line is connected to a suction pump, which is typically a jet pump or ejector. The suction pump is designed to create a vacuum in the suction line. This vacuum is applied to the suction opening, thereby drawing the gas mixture from the combustion chamber. The suction pump can be a rotary pump or a vibratory pump, for example, although other pump types, such as a jet pump, are also possible. A jet pump is a pump in which the pumping action is generated by a motive medium that draws in another medium, the so-called suction medium, through momentum exchange. Such a jet pump can, for example, operate on the principle of a Venturi nozzle. An ejector is a jet pump that generates a vacuum, thus primarily having a suction effect.The negative pressure can be used to extract the gas mixture from the combustion chamber through the extraction port. The gas mixture to be extracted from the combustion chamber is therefore the suction medium. A gaseous medium, such as air, can be used as the motive medium, provided it is supplied to the jet pump or ejector at sufficient pressure. Designing the extraction pump as a jet pump or ejector has the particular advantage that this type of pump is very simple in design and has no moving parts, making it robust and low-maintenance. Furthermore, no additional electronic components are required.

[0019] In one embodiment of the infrared emitter, the extraction line is fluid-tightly connected to a measuring chamber, the measuring chamber comprising at least one sensor for determining the air-fuel ratio of the gas composition. In particular, the measuring chamber can be arranged in the flow path from the extraction opening to the extraction pump, between the extraction opening and the extraction pump. Furthermore, the measuring chamber can be arranged on the housing and thus form an integrated measuring chamber. In particular, the measuring chamber is integrated into the extraction line. The sensor can, for example, be designed as a lambda probe, in particular as a broadband lambda probe. Advantageously, the measuring chamber can include or be connected to a processing unit and / or a communication unit in order to evaluate information, in particular a measured air-fuel ratio, acquired by means of at least one sensor.to store and / or transmit to, for example, a control unit or another communication unit.

[0020] In one design of the infrared emitter, the measuring chamber is attached to the housing. The measuring chamber can be designed to be modular and retrofittable, for example, to allow for easy replacement of a defective chamber. The measuring chamber can be integrated into the extraction duct or the housing to optimize space utilization. The measuring chamber can, for example, have a metal housing, particularly made of steel or stainless steel, and be welded to the housing. Alternatively, the measuring chamber can have a plastic housing that is screwed or glued to the housing. The measuring chamber can be located either inside or outside the housing.

[0021] In a further aspect, a heating device is proposed comprising at least one infrared emitter according to one of the embodiments described above, an air supply line connected fluid-tight to the mixing chamber of the infrared emitter for supplying air for combustion, wherein the air supply line includes an air supply control device, and a fuel supply line connected fluid-tight to the mixing chamber of the infrared emitter for supplying fuel for combustion, wherein the fuel supply line includes a fuel supply control device. An air supply line and / or a fuel supply line can also be connected to several heating devices and, in particular, several infrared emitters. The heating device can include several infrared emitters. Depending on the width of the area to be heated, for example, the width of a surface to be heated, the number of air supply lines and / or fuel supply lines can be adjusted accordingly.Depending on the type of fiber web to be dried and the desired heating output, the required number of infrared emitters can be combined into at least one heating device with a corresponding surface area. The heating device can comprise a plurality of infrared emitters, of which only a subset, in particular only at least one, is designed according to at least one of the preceding embodiments and connected to an extraction line by means of which a gas composition can be extracted from the combustion chamber.

[0022] The air supply control device and the fuel supply control device can regulate the mass or volume flow of the supplied air or fuel, respectively. An air supply control device or a fuel supply control device can, for example, be designed as a valve with an associated controllable actuator, such as a solenoid valve. Such an air supply control device or fuel supply control device can, for example, be designed to regulate the pressure in the respective air supply line or fuel supply line. By regulating the pressure in the air supply line or fuel supply line, the combustion air-fuel ratio in the combustion chamber of the infrared heater can be controlled.

[0023] In one embodiment of the heating device, a control unit is provided for regulating the air supply and fuel supply. This control unit is connected to the sensor for determining the combustion air-fuel ratio of the gas composition, the air supply control unit, and the fuel supply control unit. Such a control unit allows the combustion air-fuel ratio in the combustion chamber to be regulated based on the combustion air-fuel ratio determined by the sensor. The sensor, the control unit, the air supply control unit, and the fuel supply control unit can, for example, be wirelessly connected. The control unit can advantageously include a processing unit. Using the control unit, the combustion air-fuel ratio measured by the sensor can be compared with a predetermined target combustion air-fuel ratio, preferably stored on a memory unit.The control unit can then regulate the pressure supplied to the mixing chamber in the air supply line and / or the fuel supply line by means of the air supply control unit and the fuel supply control unit, in order to regulate the combustion air ratio in the combustion chamber of the respective infrared heater or heating device and to establish the target combustion air ratio. In one embodiment of the heating device, the suction pump, designed as a jet pump, is connected to the air supply line in a fluid-tight manner. The air from the air supply line can thus serve as the motive medium for the jet pump, and in particular for the ejector. With such a design, no additional motive medium is required. Instead, the existing pressure in the air supply line can be used to generate the vacuum in the suction line.

[0024] In a further aspect, a method for controlling the combustion air ratio of a combustion in a combustion chamber of an infrared radiator of a heating device according to at least one of the previously described embodiments is proposed, comprising the following steps: a) extracting a gas composition from the combustion chamber, b) determining the combustion air ratio of the extracted gas composition, c) controlling the air supply control device and / or the fuel supply control device to obtain a predetermined combustion air ratio of the gas composition in the combustion chamber, wherein the method is carried out continuously during the operation of the heating device.

[0025] The gas mixture is extracted from the combustion chamber via the extraction line connected to the infrared heater. The air-fuel ratio of the extracted gas mixture can then be determined in the measuring chamber. For this purpose, the measuring chamber can include, for example, a wideband lambda sensor. Controlling the combustion air ratio of the heating device involves adjusting the air supply and fuel supply controls, thus regulating the air and fuel supply respectively, to achieve the optimal air-fuel ratio in the combustion chamber. Excess air in the combustion chamber gas mixture can be compensated for, for example, by partially reducing the air supply control of the air supply line.Excess fuel in the gas composition in the combustion chamber can be compensated for, for example, by partially regulating the fuel supply control device of the fuel supply line.

[0026] The optimal combustion air ratio, or target combustion air ratio, can depend, for example, on the fuel used and, in particular, be predefined in a storage unit provided on the control device. The method can therefore additionally include the further step of specifying a predetermined combustion air ratio, especially depending on the fuel supplied.

[0027] Because the process is carried out continuously during operation of the heating device, the combustion of the gas composition in the combustion chamber of the infrared heater can always be carried out with an optimal air-fuel ratio. The efficiency of the infrared heater, or the heating device as a whole, can thus be optimized, and virtually emission-free operation can be achieved. Furthermore, deviations of the combustion air-fuel ratio present in the combustion chamber from the optimal ratio can be quickly corrected to reduce the time lag between measuring the ratio and regulating the air or fuel supply.

[0028] The following section explains exemplary embodiments of the invention as illustrated in the figures. It shows:

[0029] Fig. 1 shows a schematic sectional view of an embodiment of an infrared emitter according to the invention.

[0030] Fig. 2A is a schematic sectional view of a second embodiment of an infrared emitter according to the invention.

[0031] Fig. 2B shows a schematic sectional view of a third embodiment of an infrared emitter according to the invention.

[0032] Fig. 20 shows a schematic sectional view of a fourth embodiment of an infrared emitter according to the invention.

[0033] Fig. 3 shows a schematic representation of an example of a heating device according to the invention comprising the infrared radiator shown in Fig. 1, and

[0034] Fig. 4 shows a schematic representation of the method for controlling the combustion air ratio of a combustion process in the combustion chamber of an infrared radiator. Figures 1 to 2C each show different embodiments of an infrared radiator, with Fig. 1 showing a first embodiment of an infrared radiator 101, Fig. 2A a second embodiment of an infrared radiator 201, Fig. 2B a third embodiment of an infrared radiator 301, and Fig. 2C a first embodiment of an infrared radiator 401.

[0035] The infrared emitter 101, 201, 301, 401 comprises a mantle 2, a gas-permeable burner plate 3, and a housing 4. The housing 4, the burner plate 3, and the mantle 2 define a combustion chamber 5. The housing 4 and the burner plate 3 also define a mixing chamber 6, the mixing chamber 6 being separated from the combustion chamber 5 by the burner plate 3. The combustion chamber 5 is designed for burning a gas composition (not shown), in particular an air-fuel mixture. The combustion chamber 5 is further connected to an extraction line 7 for extracting the gas composition from the combustion chamber 5. The extraction line 7 includes an extraction opening 8. In the exemplary embodiment, the extraction line 7 is designed as a pipe, for example, made of stainless steel. The extraction opening 8 is designed as an open end of this pipe. In this case, "open design" means that no additional sieve or filter is arranged at the end of the pipe, i.e., at or in the extraction opening 8.Furthermore, the extraction opening 8 is arranged in the combustion chamber 5 in such a way that the gas composition not shown can be extracted from the combustion chamber 5 through the extraction opening 8.

[0036] The housing 4 comprises a circumferential side wall 10 and tapers towards the end of the infrared emitter opposite the mantle 2. In the illustrated embodiment, the mixing chamber 6 is located at the end of the housing 4 where the taper is situated. The combustion chamber 5 is located at the end of the housing 4 opposite the taper. The housing 4 is formed from a circumferential sheet, for example, made of steel or stainless steel, with the circumferential sheet forming the circumferential side wall 10. The burner plate 3 of the embodiment is formed from a perforated ceramic plate. The mantle 2 is formed from a rectangular, woven structure made of individual metal rods.

[0037] The extraction line 7 is fluid-tightly connected to a measuring chamber 11. The measuring chamber 11 has at least one sensor 17 for determining the air-fuel ratio of the gas composition. Such a sensor 7 can, for example, be designed as a lambda probe, in particular as a broadband lambda probe. The measuring chamber 11 is arranged downstream of the extraction opening 8 in the flow path of the extracted gas composition. The measuring chamber 11 can have or be connected to a processing unit 18 and / or a communication unit 19 in order to store measured values, such as a measured air-fuel ratio or values ​​suitable for its determination, or to transmit them to an additional processing unit and / or control unit or another communication unit.

[0038] The infrared emitter 101 shown in Fig. 1 also includes a suction pump 12 designed as an ejector. The suction pump 12 is not shown in the infrared emitters 201, 301, and 401 of Figures 2A, 2B, and 20. The ejector is located on the suction line 7, so that the measuring chamber 11 is positioned in the flow path of the extracted gas composition between the suction opening 8 and the suction pump 12. The suction pump 12 serves to generate a vacuum in the suction line 7 for extracting the gas composition from the combustion chamber 5 through the suction opening 8. The gas composition to be extracted from the combustion chamber 5 is thus the suction medium for the suction pump 12, which is designed as an ejector. A gaseous medium, for example, air, can be used as the motive medium 13, provided it is supplied to the ejector at sufficient pressure. The supply of the propellant medium 13 is only schematically indicated in Fig. 1; a reservoir is not shown.

[0039] In the infrared emitters 101 and 201 shown in Figs. 1 and 2A, the measuring chamber 11 is arranged externally on the housing 4 within a measuring chamber housing 14. The measuring chamber 11 is designed to be modular and retrofittable, for example, to allow for the easy replacement of a defective measuring chamber 11. The measuring chamber housing 14 can be made of steel or stainless steel, for example, and welded to the housing 4.

[0040] Furthermore, in the infrared emitters 101 and 201 shown in Figs. 1 and 2A, the extraction line 7 is partially arranged in a recess 15 in the burner plate 3. The extraction line 7 also passes through the side wall 10 of the housing 4 and is thus partially arranged through a recess 16 in the side wall 10 of the housing 4. In other words, the extraction line 7 passes through the side wall 10 of the housing 4 from outside the housing 4 into the interior of the housing 4 into the mixing chamber 6 and also through the recess 15 in the burner plate 3 into the combustion chamber 5. This design positions the extraction opening 8 in the combustion chamber 5 such that the gas composition can be extracted from the combustion chamber 5 through the extraction opening 8. At the same time, the extraction line 7 is routed in such a way that the cross-sectional area of ​​the infrared emitter 101, 201 is not increased, since the extraction line 7 exits the housing 4 in the area of ​​the narrowing of the housing 4.This also has the advantage that several such infrared emitters 101, 201 can be arranged next to each other without gaps in order to heat a larger area as evenly as possible, for example to dry a coating or a line on a passing fiber web evenly across the entire width of the fiber web.

[0041] In the infrared emitter 101 shown in Fig. 1, the extraction opening 8 is flush with the burner plate 3, and the extraction line 7 does not protrude into the combustion chamber 5. In this configuration, the extraction opening 8 is flush with a component of the infrared emitter 101 that delimits the combustion chamber 5, namely the burner plate 3. In the infrared emitter 201 shown in Fig. 2A, the extraction opening 8 is not flush with the burner plate 3; instead, the extraction line 7 protrudes into the combustion chamber 5, or rather, a section of the extraction line 7 is located within the combustion chamber 5. The extraction opening 8 is thus spaced apart from the elements of the infrared emitter 201 that delimit the combustion chamber 5.

[0042] In the infrared emitter 301 shown in Fig. 2B, the extraction line 7 is partially guided through a recess 16 in the side wall 10 of the housing 4 to the combustion chamber 5. The extraction line 7 is predominantly located outside the housing 4, which is why virtually no installation space inside the housing 4 is required for guiding the extraction line 7. In other words, the extraction line 7 is guided outside the housing 4 up to the level of the combustion chamber 5 and, at the level of the combustion chamber 5, is guided through the recess 16 in the side wall 10 of the housing 4 into the interior of the housing 4 and into the combustion chamber 5. In the illustrated embodiment, the extraction opening 8 is not flush with the recess 16 in the side wall 10 of the combustion chamber 5, and the extraction line 7 projects into the combustion chamber 5, or rather, a section of the extraction line 7 is located in the combustion chamber 5.The extraction line 7 and the housing 4 can be welded or soldered together at the recess 16, for example.

[0043] In the infrared emitter 401 shown in Fig. 20, the extraction line 7 is guided through a recess 15 in the burner plate 3. The extraction line 7 is located predominantly inside the housing 4 and is thus almost completely integrated into the infrared emitter 401. The extraction opening 8 is flush with the burner plate 3, and the extraction line 7 does not protrude into the combustion chamber 5. In this configuration, the extraction opening 8 is flush with a component of the infrared emitter 401 that delimits the combustion chamber 5, namely the burner plate 3. In other words, the extraction line 7 is guided almost entirely inside the housing 4 and exits the mixing chamber 6 at the end of the narrowing of the housing 4.

[0044] In the infrared emitters 301 and 401 shown in Figs. 2B and 20, the measuring chamber 11 is arranged outside the housing 4. The measuring chamber 11 can, for example, be arranged on a frame (not shown), in particular a heating device 20. It is also possible that one measuring chamber 11 is connected to several extraction lines 7 of several infrared emitters 301, 401.

[0045] Fig. 3 shows an embodiment of a heating device 20 according to the invention comprising an infrared radiator 101. The heating device 20 further comprises an air supply line 21, which is fluid-tightly connected to the mixing chamber 6 of the infrared radiator 101, for supplying air for combustion, wherein the air supply line 21 has an air supply control device 22, and a fuel supply line 23, which is fluid-tightly connected to the mixing chamber 6 of the infrared radiator 101, for supplying fuel for combustion, wherein the fuel supply line 23 has a fuel supply control device 24.

[0046] The mass of the supplied air or fuel can be regulated by means of the air supply control device 22 and the fuel supply control device 24. The air supply control device 22 and the fuel supply control device 24 are designed as valves, for example, as solenoid valves. In this respect, the air supply control device 22 and the fuel supply control device 24 are designed to regulate the pressure in the respective air supply line 21 or fuel supply line 23. By regulating the pressure in the air supply line 21 or the fuel supply line 23, and thus the mass or volume flow rate of the supplied air or fuel, the combustion air ratio in the combustion chamber 5 of the infrared radiator 101 can be regulated.

[0047] The heating device 20 also includes a control unit 27 for regulating the air supply and the fuel supply. The control unit 27 is connected, either wired or wirelessly, to the measuring chamber 11 with the sensor 17, the air supply control unit 22, and the fuel supply control unit 24. The control unit 27 regulates the combustion air ratio in the combustion chamber 5 based on the combustion air ratio of the fuel composition drawn from the combustion chamber 5, as determined by the sensor 17. The control unit 27 comprises a processing unit 28 and a storage unit 29. The control unit 27 compares the combustion air ratio measured by the sensor 17 with a predetermined target combustion air ratio stored in the storage unit 29. The processing unit 28 performs this comparison.Subsequently, the control device 27 can regulate the pressure in the air supply line 21 and / or the fuel supply line 23 by means of the air supply control device 22 and the fuel supply control device 24 in order to establish the target combustion air ratio in the combustion chamber 5.

[0048] The heating device 20 is thus suitable for carrying out a method schematically illustrated in Fig. 4 for controlling the combustion air ratio of a combustion in a combustion chamber 5 of an infrared radiator 101, 201, 301, 401 of a heating device 20 with the steps: a) extracting a gas composition from the combustion chamber 5, b) determining the combustion air ratio of the extracted gas composition, c) controlling the air supply control device 22 and / or the fuel supply control device 24 to maintain a predetermined combustion air ratio of the gas composition in the combustion chamber 5, wherein the method is carried out continuously during the operation of the heating device 20.

[0049] Reference symbol list

[0050] 101 Infrared emitters (first embodiment)

[0051] 201 Infrared emitters (second embodiment)

[0052] 301 Infrared emitter (third embodiment)

[0053] 401 Infrared emitter (fourth embodiment)

[0054] 2 incandescent elements

[0055] 3 burner plates

[0056] 4 cases

[0057] 5 Combustion chamber

[0058] 6 Mixing room

[0059] 7 Suction line

[0060] 8 Extraction opening

[0061] 10 Side panel (of the case)

[0062] 11 Measuring chamber

[0063] 12 Suction pump

[0064] 13 Propellant

[0065] 14 measuring chamber housings

[0066] 15 Recess (in the burner plate)

[0067] 16 Recess (in the side wall)

[0068] 17 Sensor

[0069] 18 computing units

[0070] 19 Communication unit

[0071] 20 Heating device

[0072] 21 Air supply line

[0073] 22 Air supply control device

[0074] 23 Fuel supply line

[0075] 24 Fuel supply control device

[0076] 25 air reservoir

[0077] 26 Fuel reservoir

[0078] 27 Control unit

[0079] 28 computing units

[0080] 29 storage units

Claims

Claims 1. Infrared emitter (101, 201, 301, 401) comprising a glowing element (2), a gas-permeable burner plate (3), a housing (4), a combustion chamber (5) suitable for the combustion of a gas composition, wherein the combustion chamber (5) is at least partially bounded by the glowing element (2), the burner plate (3) and the housing (4), a mixing chamber (6) suitable for mixing a gaseous fuel and air to form the gas composition, wherein the mixing chamber (6) is separated from the combustion chamber (5) by the burner plate (3), characterized in that the combustion chamber (5) is connected to an extraction line (7), wherein an extraction opening (8) of the extraction line (7) is arranged in the combustion chamber (5) such that the gas composition can be extracted from the combustion chamber (5) through the extraction opening (8).

2. Infrared emitter (101, 201, 301, 401) according to claim 1, characterized in that the extraction line (7) is guided at least partially through a recess (16) of a side wall (10) of the housing (4) to the combustion chamber (5).

3. Infrared emitter (101 , 201 , 301 , 401) according to at least one of the preceding claims, characterized in that the extraction line (7) is guided at least partially through a recess (15) in the burner plate (3) to the combustion chamber (5).

4. Infrared emitter (101 , 201 , 301 , 401) according to at least one of the preceding claims, characterized in that the suction line (7) is connected to a suction pump (12), which is designed in particular as a jet pump, in particular as an ejector.

5. Infrared emitter (101 , 201 , 301 , 401) according to at least one of the preceding claims, characterized in that the extraction line (7) is fluid-tight connected to a measuring chamber (11), wherein the measuring chamber (11) has at least one sensor (17) for determining the combustion air ratio of the gas composition.

6. Infrared emitter (101, 201 , 301 , 401) according to claim 5, characterized in that the measuring chamber (11) is arranged on the housing (4).

7. Heating device (20) comprising at least one infrared emitter (101, 201, 301, 401) according to at least one of the preceding claims, an air supply line (21) connected in a fluid-tight manner to the mixing chamber (6) of at least one infrared emitter (101, 201, 301, 401) for supplying air for combustion, wherein the air supply line (21) has an air supply control device (22), and a fuel supply line (23) connected in a fluid-tight manner to the mixing chamber (6) of the infrared emitter (101, 201, 301, 401) for supplying fuel for combustion, wherein the fuel supply line (23) has a fuel supply control device (24).

8. Heating device (20) according to claim 7, wherein the at least one infrared emitter (101 , 201 , 301 , 401) has the features of claim 5, characterized in that a control device (27) for controlling the air supply and the fuel supply is provided, wherein the control device (27) is connected to the sensor (17) for determining the combustion air ratio of the gas composition, the air supply control device (22) and the fuel supply control device (24).

9. Heating device (20) according to at least one of claims 7 or 8, wherein the at least one infrared emitter (101 , 201 , 301 , 401) has the features of claim 4, characterized in that the suction pump (12) designed as a jet pump is fluid-tightly connected to the air supply line (21).

10. Method for controlling the combustion air ratio of a combustion in a combustion chamber (5) of at least one infrared emitter (101, 201, 301, 401) of a heating device (20) according to any one of claims 7 to 9, comprising the following steps: a) extracting a gas composition from the combustion chamber (5), b) determining the combustion air ratio of the extracted gas composition, c) controlling the air supply control device (22) and / or the fuel supply control device (24) to obtain a predetermined combustion air ratio of the gas composition in the combustion chamber (5), wherein the procedure is carried out continuously during the operation of the heating device (20).

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