METHOD FOR EVALUATING THE INSTALLATION OF A GAS-AIR COMPOSITION OF A HEATING APPLIANCE, HEATING APPLIANCE AND COMPUTER PROGRAM

Description

[0001] The invention relates to a method for evaluating the installation of a gas-air mixture of a heating appliance, a heating appliance, and a computer program. The invention relates in particular to electronic gas-air mixtures and their installation, wherein these achieve gas volume flow control by means of an electronically controlled gas valve.

[0002] Condensing boilers typically have a modulating gas burner. This burner can be equipped with a pneumatic gas-air mixture. In this system, a blower draws air through a throttle point (orifice) to create a differential pressure, which acts (directly) on a diaphragm in the gas solenoid valve. When the blower speed is adjusted as needed, the pressure on the diaphragm changes, thus increasing or decreasing the amount of gas added to the mixture. The gas-air ratio is therefore set according to a fixed characteristic curve, which is designed for only one type of gas.

[0003] The modulating gas burner can be equipped with an electronic gas-air mixture. In this system, the volume flows of air and gas (electronically controlled) can be supplied or mixed independently of each other. Heating appliances with a combustion control method are known that utilize the dependence of the ionization current on the excess air. Depending on the output required by the heating appliance, a speed signal for the air blower and a command for an electronic stepper motor of the gas valve can be generated and transmitted. The correctness of the method or the installation can then be verified, for example, by the exhaust gas and / or flame quality. The advantage of flame monitoring is that the necessary sensor, namely the ionization electrode, is already present in many gas heating appliances.

[0004] The introduction or retrofitting of electronic gas-air mixtures and / or gas quality-adaptive heating cells not only increases the range of functions but also the complexity of the respective boiler systems. This increases the possibility of incorrect installation or settings, and these complex systems are generally much more sensitive to incorrect settings or components.

[0005] Due to the desired high degree of component reuse in heating appliances and / or the ability to compensate for many variations previously achieved mechanically via adjustment options, undesirable misconfigurations can occur during the setup or conversion of heating appliances. These can lead to a wide variety of malfunctions that are difficult to analyze retrospectively. Examples include the installation of a gas valve not intended for this appliance and / or the setting of the wrong gas type / gas family (classification for gases that are similar in their physical and combustion properties, e.g., natural gas, liquefied petroleum gas, hydrogen, biogas).

[0006] EP 2 682 679 A2 describes a method for monitoring a fuel gas-operated burner, requiring an ionization current sensor as well as a volume flow sensor or a differential pressure sensor. The required sensor equipment means that the method is not readily implementable.

[0007] EP 3 299 718 A1 discloses a method for gas type identification in which a sensor signal is processed into an air-fuel ratio measurement and assigned to a power value, and the resulting pair of values ​​is compared with a stored error range of characteristic values. This method is not suitable for evaluating the installation of a gas-air mixture.

[0008] JP 2009 210 183 A describes a method for setting an air ratio that eliminates the need for a service technician to adjust the gas pressure in a water heater. This method also requires multiple sensors and is not suitable for evaluating an installation.

[0009] It is therefore an object of the invention to at least partially alleviate the problems described with reference to the prior art. In particular, a method for evaluating the subsequent installation of an (electronic) gas-air mixture in an existing heating appliance (or heat exchanger) is to be provided, such that an incorrectly set gas mixture and / or the use of a gas valve not configured for this heating system can be reliably detected. Furthermore, a suitable heating appliance and, if applicable, a computer program suitable for its control are to be proposed.

[0010] A method according to claim 1 contributes to solving this problem. Advantageous embodiments and further developments of the invention are specified in the dependent claims. The description, particularly in conjunction with the drawings, illustrates the invention and provides further exemplary embodiments.

[0011] A method is proposed for evaluating the installation of a gas-air system in a heating appliance, which includes at least one air line with a fan and at least one gas line with a gas valve. The method specifically addresses the evaluation of new or retrofitted installations in a known or previously operational heating appliance. This may involve, for example, a conversion to an electronic gas-air system and / or the combustion of a different gas type / family. The evaluation of the gas-air system installation includes, in particular, an examination of the device-specific (equipment- and / or system-specific) design and / or settings of the gas-air system components, with a particular emphasis on the flow control components for the gas and / or air.As part of the evaluation of the installation of the gas-air system, the actual flow behavior of the gas-air system can be compared with the expected flow behavior, and thus the suitability of the (total apparatus system of the) gas-air system can be analyzed, especially with regard to an expected or actual gas that is conveyed with the gas-air system.

[0012] The structure of an (electronic) gas-air system was already explained in the introduction, so these explanations can be referred to here. The at least one air line and the at least one gas line typically lead into a mixture channel, which then supplies the fuel gas mixture to a burner. The supply of air and fuel gas mixture can be achieved by a dedicated fan or similar device. The gas supply can be regulated, for example, by an electronically controlled stepper motor in the gas valve, whereby the (fuel) gas exiting the gas valve can then be drawn into the airflow.

[0013] The burner can be housed in a separate burner casing and may, for example, include a (cylindrical) perforated plate, allowing the fuel gas mixture to pass through the holes in the plate and be ignited and burned on its surface. It is possible to monitor the formation of the flames on the burner's surface, for example, with a flame monitoring system, as already described in the introduction. This system can be used to measure the quality of combustion, which depends primarily on the air-to-gas ratio (lambda value, also called the air-fuel ratio) present during combustion, and can, for example, perform an ionization measurement within a flame area.

[0014] The procedure proposed here includes at least the following steps: a) Providing flow reference values ​​for a gas flow through the gas valve during modulation of the air flow by means of the blower; b) Monitoring current flow values ​​of a gas flow through the gas valve during modulation of the air flow by means of the blower; c) Determining a predefined significant deviation of the current flow values ​​of the gas flow from the flow reference values ​​of the gas flow; d) Evaluating the deviation by comparing a difference occurring over time and / or during air modulation between the current flow values ​​of the gas flow and its flow reference values; e) Inferring a cause of the deviation by comparison with a table or database containing sample results for a plurality or multitude of causes.

[0015] The specified sequence of steps a), b), c), d), and e) can typically occur at least once during normal operation. It is possible that the steps are executed with varying frequency, at different intervals, and / or with at least partial temporal overlap. The process can be triggered at any time, for example, by an installer. If necessary, the gas-air mixture or the heating appliance can also independently detect or specify when the process is initiated.

[0016] According to step a), flow reference values ​​for a gas flow through the gas valve can be provided when the airflow is modulated by the blower. These values ​​can be derived from, or learned from, historical flow values. The flow reference values ​​can be device- or system-specific, i.e., they can take into account or reflect, for example, the specific installation situation, the state of wear, the influence of other components, etc. The flow reference values ​​can form an (optimal or permissible) characteristic curve of the gas flow over the modulation range of the airflow adjustable by the blower. The (optimal or permissible) characteristic curve can be determined or learned based on the (previous) operation of the heating appliance, for example, by flame monitoring.A "flow reference value" for the gas flow is understood to be a specific (target) value or a (target) value range that is assigned to a specific (actual) value of the air flow. The flow reference values ​​can be stored on a data storage device and retrieved or read out as needed or continuously.

[0017] In a (test) operation, the actual gas flow rates through the gas valve can be monitored when the airflow is modulated or changed by the blower. It is possible that a specific (test) modulation range is predefined and followed. However, it is also possible that the normal, currently requested power output of the heating appliance is observed. The recorded gas flow rates can also be correlated with a temporal or airflow-dependent profile. The flow rates can be measured using sensors, allowing for the direct monitoring of an actuator that generates or influences the flow.

[0018] Particularly when a (predefinable) sufficient monitoring time has been reached, the current behavior of the flow values ​​can be evaluated once, at regular intervals, and / or (temporarily) in parallel with the flow reference values. According to the invention, a predetermined significant deviation of the current flow values ​​of the gas flow from the (historically established) flow reference values ​​of the gas flow is detected.

[0019] If this situation occurs, an assessment of the detected deviation is carried out (immediately) according to the invention. According to the invention, the assessment includes a comparison of any difference occurring over time or during air modulation between the current flow values ​​of the gas flow and its reference flow values, optionally also taking into account different modulation ranges, other process or plant parameters, etc. If both profiles form characteristic curves or ranges, their relative position to each other can be considered (calculatively).

[0020] According to the invention, the result of the evaluation leads to a conclusion regarding the cause of the deviation. For this purpose, the result is compared with a table containing sample results for a plurality or multiple causes. The cause can thus be identified and output as a process product. In other words, when a deviation is detected, the flow parameter is not (only) adjusted, as in normal burner control, so that the flame has a desired property and / or a predetermined lambda value is achieved, but rather information about the cause is provided, which can be retrieved, transmitted, and / or displayed. For example, the table (database) can contain information about the causes of the (flow-regulating) components of the gas-air mixture and / or the gas itself, from which at least one is selected using the method.In particular, the output may (at least) indicate that the gas has a property unsuitable for the gas-air system and / or that a component of the gas-air system is not compatible with this application (gas type) or has been installed incorrectly. This output specifically identifies causes that cannot be compensated for (permanently and / or across the entire modulation range) by standard control mechanisms, but rather require manual (re)setting and / or replacement of the flow-regulating components of the gas-air system. The output of the cause may be accompanied by a directive to restrict the operation of the gas-air system.

[0021] The flow reference values ​​and the current flow values ​​of the gas flow can detect or affect a volumetric flow rate. The volumetric flow rate can be detected directly or indirectly by sensors. This can include detecting an auxiliary variable that depends on the volumetric flow rate or from which a volumetric flow rate can be derived.

[0022] The gas valve may have an electronic controller, in particular a stepper motor. The controller or its operating parameters can be used to measure or calculate the volumetric flow rate of the gas flow.

[0023] This procedure can be initiated, in particular, if it is determined that the electronic regulator of the gas valve was previously without power or is only now being powered again. The fact that the gas valve was disconnected from the electrical power supply can also be taken into account when identifying the cause of a detected deviation.

[0024] The gas-air system may also include means for detecting the type of gas. These means could include, for example, at least one sensor, a gas-specific connection element, a gas-specific software application, etc.

[0025] The procedure can be initiated, in particular, if a change in the type of gas is detected or has been detected shortly beforehand. The fact that a change in the type of gas has been detected can also be taken into account when identifying the cause of a detected deviation.

[0026] In step d), the deviation pattern over a modulation range of the airflow can be evaluated. It is possible that the deviation of the values ​​over a (considered or predefined) modulation range is approximately constant, increases abruptly, (temporarily) continuously, and / or decreases, oscillates around a mean value with a certain amplitude, etc. The result of this evaluation can be used for step e).

[0027] Depending on the result of step e), at least two different causes can be identified and output. In particular, the causes "incorrect gas fitting" and "incorrect gas type / gas family" can be identified and specified. It is possible that a large number of other causes can be identified in this way.

[0028] Step a) can be carried out taking into account historical flow values ​​of the gas flow in the gas-air mixture. For example, it is possible to determine or adjust appropriate flow reference values ​​through a learning process during the (previous) operation of the gas-air mixture of the heating appliance. Qualification as an acceptable flow reference value can be achieved, for example, via flame detection.

[0029] During the execution of the procedure, preferably no (further) flow reference values ​​of the gas flow are generated or changed. This can (only) be continued, for example, if the procedure has been completed without detecting any deviation.

[0030] Following a further aspect, a heating device is proposed with a gas-air system, comprising at least an air line with a blower, a gas line with a gas valve, a control and regulating unit for adjusting an adapted gas flow through the gas valve when modulating the air flow, and means adapted to perform the steps of the inventive method.

[0031] The preceding explanations regarding the gas-air mixture of a heating appliance and the method can be used to further characterize the device. In particular, the gas-air mixture of the heating appliance can be configured in such a way that it can perform the method described here.

[0032] Furthermore, a computer program is proposed, comprising commands that cause the heating device according to the invention to execute the steps of the method according to the invention. The computer program can, for example, be implemented in a control unit of a heating device.

[0033] The solutions presented here, as well as their technical context, are explained in more detail below with reference to the figures. It should be noted that the invention is not intended to be limited by the illustrated embodiments. In particular, unless explicitly stated otherwise, it is also possible to extract partial aspects of the matters explained in or in connection with the figures and combine them with other applications.

[0034] to combine components and / or insights from other figures and / or the present description. The following are shown by way of example and schematically: Fig. 1: an example of an electrical gas-air compound of a heating appliance, Fig. 2: an illustration for obtaining flow reference values, and Fig. 3: an evaluation of a deviation within the framework of the method disclosed herein.

[0035] Fig. 1 Figure 1 shows a gas-air system 1 of a heating appliance 2, which has an air line 3 with a blower 4 and a gas line 5 with a gas valve 6. The gas valve 6 includes an electric regulator 7 which can be adjusted by a control unit 8 to enable a controlled gas flow through the gas valve 6, even if the air flow is modulated by the control unit 8. The air line 3 and the gas line 5 terminate in a common mixture line 9, which leads to a burner 10. The mixture is combusted in the chamber surrounding the burner 10, where a flame monitoring device 11 can be provided to transmit signals to the control unit 8 regarding the current flame formation. The exhaust gas from this combustion can be discharged via an exhaust line 12. The means are adapted to perform the steps of the method disclosed herein.

[0036] Fig. 2 This illustrates, by way of example, that for a desired combustion quality, an (ideal) target volume flow of the gas can be specified when modulating the air (left diagram in Fig. 2 With such a setting, the heating appliance can, for example, be operated at the beginning. Theoretically, or ideally, a linear relationship results, as indicated by the dashed line on the right. However, this does not occur in practice; instead, a system-related deviation is observed. Nevertheless, a system-specific, adjusted actual volume flow rate can be determined (e.g., using feedback from the flame monitoring results) at which the desired flame quality is actually achieved (right-hand diagram in [reference]). Fig. 2 These volume flow values ​​can be recorded as flow reference values ​​(SR) and made available for retrieval.

[0037] In particular with a gas-air compound 1 according to the Fig. 1 and according to Fig. 2 The learned flow reference values ​​SR allow the method according to claim 1 to be carried out for evaluating the (successful or faulty) installation of the gas-air compound 1.

[0038] Fig. 3 This illustrates how this can be done, particularly within the framework of steps d) and / or e). A diagram is shown there in which various flow curves of the gas flow are depicted over a given modulation range M or the blower speed. The percentage deviation from the ideal curve is shown (see Fig. 2 (right) illustrated.

[0039] The lower section illustrates the (learned or historical) course V of the flow reference values ​​SR. This includes a tolerance or permissible range above and below, whereby the tolerance direction and / or width can be predefined and / or also learned. This can therefore be provided as part of step a). If the currently recorded flow values ​​S are within or at the flow reference values ​​SR, a correct installation can be assumed.

[0040] The first curve V of the flow values ​​S1 currently determined in step b) is illustrated above. These values ​​deviate significantly A1 from the curve V of the flow reference values ​​SR, at least in one sub-area, so that a deviation A1 is determined according to step c). According to step d), the deviation A1 can be assessed such that it increases in the upper or right modulation range. This assessment result leads in step e) to the conclusion that the cause is highly likely to be an incorrect gas valve 6 (with a locally altered design / geometry).

[0041] The diagram also illustrates a second flow curve V of the flow values ​​S2 currently determined in step b). These deviate significantly A2 from the flow curve V of the flow reference values ​​SR, so that a deviation A2 is determined according to step c). According to step d), the deviation A2 can be assessed such that it is essentially constant in the modulation range. This assessment result leads in step e) to the conclusion that the cause is highly likely to be an incorrect gas type (with consistently deviating combustion behavior). Reference symbol list

[0042] 1 Gas-air mixture 2 Heater 3 Air duct 4 Blower 5 Gas line 6 Gas valve 7 Electronic regulator 8 Control and monitoring unit 9 Mixture line 10 Burner 11 Flame monitoring 12 Exhaust pipe S Flow value SR Flow reference value A Deviation M Modulation range V Curve

Claims

1. Method for evaluating an installation of a gas-air composite (1) of a heating device (2), which has an air duct (3) with a fan (4) and a gas duct (5) with a gas fitting (6), wherein the method comprises at least the following steps: a) providing flow reference values (SR) of a gas flow through the gas fitting (6) during modulation of the air flow by means of the fan (4); b) monitoring current flow values (S) of the gas flow through the gas fitting (6) during modulation of the air flow by means of the fan (4); c) detecting a predetermined significant deviation (A) of the current flow values (S) of the gas flow from the flow reference values (SR) of the gas flow; d) Evaluating the deviation (A) by comparing a difference occurring over time and / or during air modulation between the current flow values (S) of the gas flow and their flow reference values (SR); e) Concluding on a cause of the deviation (A) by comparing with a table or database comprising sample results for a plurality or multitude of causes.

2. Method according to claim 1, wherein step d) comprises weighting different modulation ranges, including further process parameters or including further plant parameters.

3. Method according to one of the preceding claims, wherein cause information relating to the components of the gas-air mixture and / or the gas that regulate the flow is stored in the table or database, from which at least one is selected by means of step e).

4. Method according to one of the preceding claims, in which the flow reference values (SR) and the current flow values (S) record a volume flow.

5. Method according to one of the preceding claims, wherein the gas fitting (6) has an electronic controller (7), and the method is initiated when the electronic controller (7) was previously de-energised.

6. Method according to one of the preceding claims, wherein means for detecting the gas type are provided, and the method is initiated when a change in the gas type is detected.

7. Method according to one of the preceding claims, in which in step d) a progression (V) of the deviation (A) over a modulation range (M) of the air flow is evaluated.

8. Method according to one of the preceding claims, wherein, depending on the result of step e), at least two different causes are identified and output.

9. Method according to one of the preceding claims, wherein step a) is performed taking into account historical flow values (S) of the gas flow of the gas-air composite (1).

10. Method according to one of the preceding claims, in which no flow reference values (SR) of the gas flow are changed during the execution of the method.

11. Heating device (2) with a gas-air composite (1), comprising at least an air duct (3) with a fan (4), a gas duct (5) with a gas fitting (6), a control and regulation unit (8) for setting an adjusted gas flow through the gas fitting (6) when modulating the air flow, and means adapted to carry out the steps of the method according to claim 1.

12. Computer program comprising instructions that cause the heater of claim 11 to perform the steps of the method according to claim 1.