阅读说明：本技术 用于在燃气运行的加热器的启动过程中识别燃气种类的方法和燃气运行的加热器 (Method for identifying a gas type during the start-up of a gas-operated heater and gas-operated heater ) 是由 S·沃尔德 J·丹纳曼 E·罗力克 H·亨里奇 H-J·克林克 J·赫尔曼 于 2019-01-18 设计创作，主要内容包括：本发明涉及一种方法,所述方法在使用气体质量传感器在燃烧器起动之前确定燃气种类的情况下用于在燃气运行的加热器的启动过程中识别燃气种类,所述燃气运行的加热器具有电子气体-空气混合器。(the invention relates to a method for identifying a gas type during the start-up of a gas-operated heater having an electronic gas/air mixer, using a gas mass sensor to determine the gas type before the start-up of a burner.)

1. Method for identifying a gas type during the start-up of a gas-operated heater (100) having an electronic gas-air mixer, wherein the heater (100) comprises at least one fan (5) for delivering a volumetric flow of air, a gas supply having a gas control means (2) for the regulated supply of gas, a burner (28), an ignition unit for igniting the burner (28), a sensor arranged in the gas supply and flowed through by the gas, and a controller (9) for regulating at least the volumetric flow of air delivered by the fan (5) and the gas control means (2) determining a gas mass flow of gas, wherein the heater (100) comprises a gas supply for delivering a volumetric flow of air, a burner (28) for igniting the burner (28), a sensor arranged in the gas supply and a controller (2) for regulating at least the volumetric flow of air delivered by the fan (5) and determining a gas

a. The sensor is designed as a gas mass sensor for determining a gas mass and a physical property associated with the gas mass,

b. The physical properties of the gas are measured by the gas quality sensor (3) and transmitted to the controller (9),

c. The controller (9) determines the gas type from the measured physical property of the gas,

d. The control unit (9) on the gas control means (2) regulates a first start gas mass flow as a function of the determined gas type, said first start gas mass flow being below the ignition limit of the gas of the determined gas type,

e. in the case of an ignition test of the ignition unit, the supplied gas mass flow increases from the start gas mass flow at a constant air volume flow until exceeding the ignition range for the determined gas type,

f. During the ignition test, ignition of the burner (28) is monitored and detected.

2. Method according to claim 1, characterized in that the controller (9) on the gas control means (2) adjusts a second start-gas mass flow in dependence on the determined gas type in the case of non-ignition, which is smaller than the first gas mass flow and further below the ignition limit of the gas of the determined gas type, wherein steps e) to f) of claim 1 are subsequently performed.

3. method according to claim 1 or 2, characterized in that in the case of an ignition test of the ignition unit, the supplied gas mass flow is steadily increased starting from the start gas mass flow at a constant air volume flow.

4. Method according to any of the preceding claims, characterized in that during the start-up of the gas-operated heater (100), after first installation of the gas-operated heater, an exhaust of the gas duct of the gas supply is first performed, wherein the controller switches on the gas control means (2) and transmits a signal to the controller (9) via the gas quality sensor (3), once gas is detected.

5. Method according to any one of claims 1 to 3, characterized in that during the start-up of the gas-operated heater (100), after the first installation of the gas-operated heater, an exhaust of the gas duct of the gas supply is first carried out, wherein the start-up procedure with steps b) to f) is repeated until ignition of the burner is detected.

6. Method according to any one of the preceding claims, characterized in that the controller (9) calculates the actual air volume flow from the fan speed measured by the controller (9), a characteristic curve determined in advance in the laboratory and the current consumption of the fan (5).

7. method according to any of the preceding claims, characterized in that the gas mass flow is regulated by an electrically modulated gas control means (2), wherein the gas control means (2) obtains a regulating signal by means of the controller (9).

8. Method according to one of the preceding claims, characterized in that the air requirement assigned to the respective gas type is determined from the gas type determined by the gas mass sensor (3).

9. Method according to one of the preceding claims, characterized in that the gas mass sensor for determining the gas mass and the physical properties associated with the gas mass is designed as a hot gas mass sensor (3) which measures the thermal conductivity of the gas.

10. Method according to one of claims 1 to 8, characterized in that the gas mass sensor for determining the gas mass and the physical properties associated with the gas mass is designed as an ultrasonic gas mass sensor (3) which measures a gas-specific sound velocity.

11. Gas-operated heater (100) with an electronic gas-air mixer, wherein the heater (100) comprises at least one fan (5) for delivering an air volume flow, a gas supply with a gas control means (2) for the regulated supply of gas, a burner (28), an ignition unit for igniting the burner (28), a sensor arranged in the gas supply and flowed through by the gas, and a controller (9) for regulating at least the air volume flow delivered by the fan (5) and the gas control means (2) determining a gas mass flow of gas, wherein,

a. The sensor is designed as a gas mass sensor for determining a gas mass and a physical property associated with the gas mass,

b. the physical properties of the gas are measured by the gas quality sensor (3) and transmitted to the controller (9),

c. The controller (9) determines the gas type from the measured physical property of the gas,

d. The control unit (9) on the gas control means (2) regulates a first start gas mass flow as a function of the determined gas type, said first start gas mass flow being below the ignition limit of the gas of the determined gas type,

e. in the case of an ignition test of the ignition unit, the supplied gas mass flow increases from the start gas mass flow at a constant air volume flow until exceeding the ignition range for the determined gas type,

f. During the ignition test, ignition of the burner (28) is monitored and detected.

Technical Field

The invention relates to a method for identifying a gas type in a gas-operated heater.

Background

As gas categories, low-calorie and high-calorie natural gases and liquefied gases are currently distinguished in particular.

From the prior art, for example in german patent application DE 102017126137.0, a method for mixture regulation is known, which is based on a gas mass flow sensor in combination with a mixture calibration by flame flow measurement. However, this basically envisages a mixing regulation during the operation of the burner.

When starting the burner of the heater, the combustible gas-air mixture is to be adjusted in the shortest possible time. Since the optimum gas-air ratio and ignition performance are different for different gases, it is necessary to determine the gas type before or during the start of the burner to adjust both the gas amount and the air amount to the optimum start-up conditions.

In the electronic gas-air mixture control for a heater, operating parameters dependent on the gas type must be taken into account. In liquefied gases, the modulation range is generally smaller than in natural gas. Further, the air values at the respective power points in the modulation range of the heater are different from each other. In order to automatically adapt the heater to the respective available gas type, an automatic gas type identification is required.

Conventionally, gas species identification is performed during operation of the burner. In this case, the combustion regulation is carried out, for example, according to the ionization principle, wherein the gas/air ratio is adapted such that clean, complete combustion is present. The type of gas used can be inferred from the ratio of the gas quantity to the air quantity during the combustion operation, since the air quantity required for the respective gas type is known. However, this information is only indirectly available, for example in the form of fan speed (air quantity) or gas control valve actuation (control or actuation signal), and is therefore very inaccurate. Furthermore, it is not possible to take into account the gas type when starting the burner or even when commissioning the heater for the first time. The failure diagnosis cannot be performed if the heater is not put into operation. When, for example, a gas type is erroneously stored in the heater, it is likely that the burner is not ignited and the heater is not activated.

Disclosure of Invention

It is therefore the object of the present invention to provide a method with which the type of gas is determined before the heater is started and is used for the start-up process.

This object is achieved by a combination of the features according to claim 1.

according to the invention, a method is proposed for identifying the type of gas during the start-up of a gas-operated heater having an electronic gas/air mixer, wherein the heater comprises at least one fan for delivering an air volume flow, a gas supply having a gas control for the regulated supply of gas, a burner, an ignition unit for igniting the burner, a sensor arranged in the gas supply and flowed through by the gas, and a controller for regulating at least the air volume flow delivered by the fan and the gas control for determining a gas mass flow of the gas.

The sensor is designed as a gas mass sensor for detecting the mass of the gas supplied to the burner and further physical properties of the gas, with which the composition of the gas can be inferred. For example, calorimetric microsensors are used for this purpose, which detect the thermal conductivity of the gas in addition to the gas quality. Another possibility consists in at least one sensor which determines the gas quality and the current, specific speed of sound associated with the respective gas on the basis of the operating principle of the ultrasonic measurement.

In the method according to the invention, at least one of the aforementioned physical properties of the gas (e.g. thermal conductivity) is measured by a gas mass sensor and transmitted to a controller. The controller then determines the gas type from these measured properties of the gas.

subsequently, the control unit on the gas control device adjusts a first start gas mass flow as a function of the determined gas type, said first start gas mass flow being below the ignition limit of the gas of the determined gas type. The ignition limit of the respective gas type is known and can be stored in the control unit, for example, in the form of a characteristic curve.

then, in the case of a continuous ignition test by the ignition unit, the supplied gas mass flow is increased from the start gas mass flow at a constant air volume flow until the ignition range of the gas species determined in advance is exceeded. During the ignition test, it is monitored and detected by the controller whether ignition of the burner has occurred. For this purpose, electrodes can be used, for example, on the burner, which transmit a flame signal to the control unit when the burner is fired.

In liquefied gas and natural gas, the ignition ranges of the respective gas types differ, since a high-calorific gas, for example liquefied gas, ignites earlier at the same air volume flow than a low-calorific gas, for example low-calorific natural gas (L-gas). In this case, it is technically clearly defined in which ranges of the gas-air mixture the respective ignition range of the respective gas lies.

By means of the method according to the invention, it is achieved that the type of gas is already determined before the burner is ignited and the gas/air mixture required for starting is limited to a small extent. The optimal gas-air mixture for starting the burner is quickly identified and achieved. Thereby, the start-up time is shortened and the number of failed attempts at start-up of the burner is reduced.

If it can be determined in the starting method that the burner is not firing, in a further development it is provided that the control unit on the gas control device adjusts a second starting gas mass flow, which is smaller than the first gas mass flow and further below the firing limit of the gas of the determined gas type, as a function of the determined gas type. Subsequently, the following steps of the above-described startup method are directed here: in the case of a continuous ignition test of the ignition unit, the supplied gas mass flow increases from the start gas mass flow at a constant air volume flow until the ignition range of the previously determined gas type is exceeded. In this case, it is advantageous if the range of the gas/air mixture available for the start-up process of the burner can be enlarged and the burner start-up can be achieved even if the first starting gas mass flow determined is not suitable.

the method is characterized in an embodiment in that, in the case of an ignition test in an ignition unit, the supplied gas mass flow is steadily increased from a start gas mass flow at a constant air volume flow. A constant air volume flow is possible by the controller adjusting a constant fan speed.

The method is further characterized in that the controller calculates the actual air volume flow from the fan speed measured by the controller, a characteristic curve determined in advance in the laboratory, and the current consumption of the fan.

The method not only relates to burner start-up in general, but also to burner start-up when the heater is first commissioned. For this purpose, in a further development of the method, it is provided that, during the start-up of the gas-operated heater, after the first installation of said gas-operated heater, an exhaust of the gas line of the gas supply is first carried out, wherein the controller switches on the gas control means and transmits a signal to the controller via the gas mass sensor as soon as gas is detected. The gas mass sensor can be used at any time to detect air in the gas supply in order to facilitate the venting of the gas duct.

In an alternative variant of the method, during the start-up of the gas-operated heater, after the first installation of the gas-operated heater, an exhaust of the gas line of the gas supply is first carried out, wherein the aforementioned start-up procedure for solving the task is repeated until ignition of the burner is detected.

In general, in the method it is preferably provided that the gas mass flow is regulated by an electrically modulated gas control, wherein the gas control receives a regulating signal from a controller and thus adapts the gas mass flow as required.

In addition, in the method, it is preferably provided that the air requirement associated with the respective gas type is determined from the gas type determined by the gas mass sensor and is used for further regulation of the operation of the heater. For this purpose, the control device preferably has stored therein a corresponding value or characteristic curve, which can be accessed for the regulation or future starting process. Here, the parameters known in the prior art are also accessed, for example, liquefied gas requires three times more air than natural gas at the same volume to ensure complete combustion.

Drawings

Further advantageous developments of the invention are characterized in the dependent claims or are explained in detail below together with the description of preferred embodiments of the invention with reference to the drawings.

the figures show:

FIG. 1 is a schematic configuration of a heater;

FIG. 2 is a graph of a method flow for high-calorie fuel gas;

Fig. 3 is a graph of the process flow for a low-calorie gas.

Detailed Description

In fig. 1 is a schematic structure of a heater 100 for performing a method with a modulated premixing fan 5 which draws in ambient air a and mixes it with the gas. The combustion gas is supplied to a premixing fan 5 via a gas nozzle 4 in a gas duct, wherein a gas control mechanism or gas valve 2, which can be electronically controlled by the engine M, and a hot gas mass sensor 3 are arranged in the gas duct upstream of the gas safety valve 1. The gas inlet pressure d is adjusted to the gas regulation pressure c. After mixing with the ambient air, the gas-air mixture has a mixing pressure b. In the embodiment shown, an optional check valve 6 is provided on the fan outlet. The mixture then has a burner pressure e. Thereafter, a burner 28 is connected, which has an electrode 7 arranged in the burner flame, with which the flame on the burner 28 is detected and a corresponding signal is transmitted to the controller 9. A heat exchanger 18 is arranged around the burner 28. Continuously in the flow direction, the exhaust system with the exhaust valve 8 follows. In the exhaust system, the exhaust pressure f prevails. The regulation of the gas quantity and the fan speed and, as a matter of course, the air quantity flowing through the gas control means 2 takes place via a control unit 9, in which the corresponding control characteristic is stored and can be stored. The corresponding signal lines to and from the controller 9 are characterized by arrows.

Fig. 2 shows the flow of the method for gas species identification of high-calorific gas, after the thermal conductivity of the applied gas has been measured by the hot gas mass sensor 3 and transmitted to the controller 9. In the method, first of all in a time period t1 to t2, the air volume flow VL is set to a constant value by the fan 5. In the exemplary embodiment shown, when a constant air volume flow VL is reached, the gas mass flow VG, which is set by the gas control means 2 via the gas line, is set to a starting gas mass flow which is below the lower ignition limit z1 of the ignition range HG of the high-calorific gas. Subsequently, the controller 9 regulates the gas control means 2 during the time period t2 to t3 with the air volume flow VL constant in order to increase the gas mass flow VG supplied to the fan 5 steadily from the start gas mass flow, in the case of continued ignition tests of the ignition unit, until the ignition range HG of the high-heat gas is exceeded and the upper ignition limit z2 of the high-heat gas is exceeded. As long as there are no abnormal frame conditions that prevent burner startup, the burner 28 ignites during the time period t2-t3 and then burns during the time period t3-t4 when the gas mass flow VG is adjusted to be constant. The amount of gas required for the low-calorie gas and (necessarily) the ignition range LG of the low-calorie gas are not reached.

Fig. 3 shows a method which refers to the same diagram as fig. 2, as long as the low-calorific gas is determined by the hot gas mass sensor 3. The gas mass flow VG then increases from the beginning to exceed the ignition range HG of the high-calorie gas with a constant air volume flow VG, wherein the initial gas mass flow is below the lower ignition limit z3 of the ignition range LG of the low-calorie gas. Subsequently, the controller 9 regulates the gas control means 2 during the time period t2 to t3, with a constant air volume flow VL, in order to increase the gas mass flow VG supplied to the fan 5 steadily from the start gas mass flow, in the case of a continuous ignition test by the ignition unit, until the ignition range LG of the low-calorie combustion gas is exceeded and the upper ignition limit z4 of the low-calorie combustion gas is exceeded. As long as there are no abnormal frame conditions that prevent burner startup, the burner 28 ignites during the time period t2-t3 and then burns during the time period t3-t4 when the gas mass flow VG is adjusted to be constant.