METHOD FOR DETECTING A BLOCKED CONDENSATE DRAIN OF A HEATING APPLIANCE, COMPUTER PROGRAM, CONTROL AND REGULATION DEVICE AND HEATING APPLIANCE

Description

[0001] The invention relates to a method for detecting a blocked condensate drain of a heater, a computer program, a control and regulating device and a heater.

[0002] Condensate typically accumulates in a heater during a combustion process (e.g., of natural gas or hydrogen). According to state-of-the-art technology, the condensate collecting in the heater's combustion chamber is drained from the combustion chamber and the heater to a drain via a condensate drain, often comprising a siphon.

[0003] A blocked drain or siphon can cause significant problems. If the drain is blocked, condensate can rise in the combustion chamber and potentially flow into the burner or even further into the gas supply. This can cause significant damage to the heater and require extensive repairs.

[0004] In devices with ionization current-based flame detection, the ionization electrode can be located below the burner. If the condensate drain is blocked, the condensate could only collect up to the level of the ionization electrode because, upon contact between the ionization electrode and the condensate, the ionization current breaks off, and the heater shuts down due to a lack of flame detection. Such a solution is described, for example, in EP 3 081 861 A1. However, this solution cannot be used in hydrogen-powered heaters because a hydrogen flame does not release sufficient electrical charge carriers to detect an ionization current, and thus a collapse of the ionization current due to a ground fault of the ionization electrode caused by a rise in the condensate level cannot be detected.

[0005] GB 2187 829A proposes, to prevent a heater drain from becoming blocked, collecting condensate generated in the heater in a container and then emptying the entire container via the drain. This is intended to reduce the risk of a drain blockage.

[0006] GB 249 7140 A proposes providing a connector in a condensate drain pipe with a switch that can be activated by condensate flowing inside the drain pipe. The switch can then, via communication, trigger another switch to shut off the heater.

[0007] GB 2 146 157 A describes the detection of a blocked condensate drain using an additional electrode in the condensate drain. The disadvantage is that the additional electrode must be installed in the condensate drain to implement this method.

[0008] The main disadvantage of these solutions is their complexity, which not only increases the probability of failure but also increases the costs of manufacturing and assembly.

[0009] Based on this, the object of the invention is to propose a method for operating a heater that at least partially overcomes the described problems of the prior art. In particular, the method is intended to provide a very simple and reliable way to detect a blockage in a (condensate) drain and prevent subsequent damage.

[0010] In addition, the invention should at least not significantly increase the complexity of a heating device, require only minor structural changes to a heating device and enable easy integration into an existing production process or even easy retrofitting of existing systems.

[0011] These objects are achieved by the features of the independent patent claims. Further advantageous embodiments of the solution proposed here are specified in the independent patent claims. It is pointed out that the features listed in the dependent patent claims can be combined with one another in any technologically expedient manner and define further embodiments of the invention. Furthermore, the features specified in the patent claims are further specified and explained in the description, with further preferred embodiments of the invention being presented.

[0012] A method for detecting a blocked condensate drain of a heater contributes to this, comprising at least the following steps: a) Recording an operating parameter (of the heater or an associated component) which allows a conclusion to be drawn about an (electrical) voltage amplitude at an ionization electrode of a flame detection device, b) Comparing the operating parameter recorded in step a) with a (predetermined) limit value, c) Detecting a blocked condensate drain (from the comparison in step b)), wherein the operating parameter recorded in step a) is a manipulated variable of a control loop for keeping the voltage amplitude of an alternating voltage signal of the ionization electrode of the flame detection device constant.

[0013] In a regular procedure, steps a), b) and c) can be carried out at least once in the specified order.

[0014] The invention can, in particular, be used for the automatic detection of a blocked condensate drain of a heater. A blockage of the drain would result in condensate no longer being able to drain from the combustion chamber of the heater and accumulating in the combustion chamber, which can lead to significant damage to the heater. The invention is based in particular on the idea of ​​detecting a blocked condensate drain and the associated contact of an ionization electrode with the condensate using an operating parameter that allows a (direct) conclusion about the voltage amplitude of an ionization-based flame detection system.

[0015] In principle, a method proposed here can be used in any heating device during whose operation a significant amount of condensate can be generated. The heating device can have an ionization current-based flame detection system as a primary or secondary (redundant) system, by means of which a method described here can be carried out. Heating devices that use hydrogen as a fuel may have flame detection based on the UV (ultraviolet) radiation of the flame as the primary system and may additionally have a redundant ionization current-based system, which can be used to carry out a method proposed here. For this purpose, the heating device can have a device for ionization current-based flame detection, comprising an ionization electrode, which can be positioned in or in the immediate vicinity of a flame of the heating device.The device for ionization current-based flame detection may also comprise an (electrical) circuit with a transformer that can provide an alternating voltage to the ionization electrode and a control circuit that can regulate the voltage amplitude of this alternating voltage.

[0016] The heater is, in particular, a gas heater designed to burn a gaseous fuel, such as natural gas or, in particular, hydrogen, with the addition of ambient air, in order to provide heat, for example, for a heating circuit and / or a hot water supply. The heater generally has at least one burner and a conveying device (such as a fan) that conveys a mixture of fuel (in particular, a fuel gas) and combustion air through a mixture channel of the heater to the burner. The exhaust gas produced by the combustion can then be guided through an exhaust pipe of the heater to an exhaust system. In addition, the heater has an outlet for (liquid) condensate produced during combustion. The outlet can comprise a siphon. The condensate can be guided to a suitable location, for example, a sewer, via the outlet and / or the siphon.

[0017] The drain is usually located at the (geodetically) lowest point of the combustion chamber (in the operating position) to ensure the most complete drainage of the condensate. The drain often includes a siphon, i.e., a U-shaped area that seals the drain gas-tight, preventing external air from entering the combustion chamber. A blockage of the drain is often caused by or within the siphon. A blockage of the drain can result in its complete closure or in such a reduced drainage velocity that the condensate cannot drain away sufficiently and collects in the combustion chamber. A "blockage" here, therefore, specifically means that the condensate cannot drain away or can only drain away insufficiently.

[0018] According to step a), an operating parameter of the heater or a part of the heater is recorded (preferably by measurement and / or automatic means), which allows a conclusion to be drawn about the voltage amplitude of an ionization electrode of the flame detection system. Advantageously, a control variable for maintaining the voltage applied to the ionization electrode constant can be recorded directly from the voltage control system. The control variable will often be a PWM (pulse width modulated) signal. Thus, a known device for ionization current-based flame detection can be used particularly advantageously for a method presented here.

[0019] According to step b), the operating parameter recorded in step a) is compared with a limit value. The limit value can represent a threshold value, below or above which contact between the ionization electrode and condensate and an associated (electrical) short circuit to ground or a conductive connection between the electrode and the reference potential (typically the device ground) can be assumed with certainty. The limit value can be selected in particular with regard to the heater and / or its surroundings and / or its fuel mixture or the combustion process. The limit value can be fixed; it can also be variably determined and specified automatically, e.g. with regard to relevant parameters of the current combustion and / or ambient conditions.

[0020] According to step c), a blocked condensate drain can be detected from the comparison from step b), in particular when the limit value is reached, undershot, or exceeded. For example, if the operating parameter recorded in step a) is a control variable for maintaining a constant voltage at the ionization electrode, a blocked condensate drain can be detected in step c) when the control variable reaches or exceeds a limit value. If the operating parameter is the (unregulated) voltage of the ionization electrode, reaching or falling below a limit value can indicate a blocked condensate drain. The limit value can therefore be determined based on the behavior of the operating parameter recorded in step a) when the ionization electrode comes into contact with condensate, for example based on tests on a reference heater.The limit value can be stored in a memory, in particular in a memory of a control and regulation device of the heater.

[0021] According to an advantageous embodiment, the heater can be (automatically) shut down in step d) if a blocked process is detected in the heater (step c). This can, in particular, result in the automatic shutdown of the heater's burner.

[0022] According to a further advantageous embodiment, upon detection of a blocked condensate drain according to step c), the heater can provide or send information about the blocked condensate drain in a step e). Advantageously, the heater can thus automatically inform an operator, user, or specialist company about the blocked condensate drain and, if necessary, a shutdown of the heater (step d)). Particularly advantageously, the information can be provided or sent via a network, in particular the Internet. For example, after detecting a blocked condensate drain of the heater according to step c), the heater could automatically send information about this to a selected specialist company, which can plan and carry out a maintenance appointment to clear the blocked drain.

[0023] According to an advantageous embodiment, the operating parameter in step a) can be detected via a combined ignition and ionization electrode.

[0024] The process is suitable for a gas-powered heating device that uses hydrogen or natural gas as fuel.

[0025] According to a further aspect, a computer program is also proposed which is configured to (at least partially) carry out a method presented here. In other words, this relates in particular to a computer program (product) comprising instructions which, when executed by a computer, cause the computer to execute a method described here.

[0026] According to a further aspect, a machine-readable storage medium on which the computer program is stored is also proposed. The machine-readable storage medium is usually a computer-readable data carrier.

[0027] According to a further aspect, a control device for a heater is also proposed, configured to implement a method presented here. The control device can, for example, comprise or have a processor for this purpose. In this context, the processor can, for example, execute the method stored in a memory (of the control device). Furthermore, one or more limit values ​​for implementing a method presented here can also be stored in a memory of the control device.

[0028] According to a further aspect, a heating device with a control and regulation device as presented here is also proposed. The heating device is, in particular, a gas heating device with a gas burner and a conveying device that can convey a mixture of gas (in particular hydrogen) and combustion air to the gas burner.

[0029] According to a further aspect, the use of an operating parameter which allows a conclusion to be drawn about the voltage amplitude of an ionization electrode of a flame detection device is proposed for detecting a blocked condensate drain of a heating device.

[0030] The details, features, and advantageous embodiments discussed in connection with the method may also occur in the computer program, storage medium, control device, heater, and / or use presented here, and vice versa. In this respect, reference is made in full to the explanations therein for a more detailed characterization of the features.

[0031] Thus, a method for detecting a blocked condensate drain of a heater, a computer program, a storage medium, a control device, a heater, and the use of an operating parameter are specified here, which at least partially solve the problems described with reference to the prior art. In particular, the method, the computer program, the control device, the heater, and the use at least contribute to reliably detecting a blockage of the condensate drain of a heater. Particularly advantageously, the method can be implemented without physically modifying a heater by implementing a computer program. Thus, the complexity of a heater presented here corresponds to that of a heater according to the prior art.

[0032] The invention and the technical environment are explained in more detail below with reference to the accompanying figures. It should be noted that the invention is not intended to be limited by the exemplary embodiments cited. In particular, unless explicitly stated otherwise, it is also possible to extract partial aspects of the facts explained in the figures and combine them with other components and findings from the present description. In particular, it should be noted that the figures and, in particular, the proportions shown are only schematic. They show: Fig. 1: a sequence of a method proposed here, Fig. 2: a combustion chamber of a heating device proposed here, Fig. 3: a heating device proposed here, Fig. 4: a schematic representation of a control circuit for flame monitoring, and Fig. 5: a schematic representation of a structure of a circuit for flame detection.

[0033] Fig. 1 shows, by way of example and schematically, a sequence of a method proposed here. The method serves to detect a blocked condensate drain 14 of a heater 1. The sequence of steps a), b), and c) represented by blocks 110, 120, and 130 can occur during regular operation. In particular, however, a simultaneous (permanent) or regularly staggered execution of steps a) to c) may be appropriate.

[0034] In block 110, according to step a), an operating parameter is recorded that allows a conclusion to be drawn about the voltage amplitude of an ionization electrode 13 of a flame detection system. In block 120, according to step b), the operating parameter recorded in step a) is compared with a limit value. In block 130, according to step c), a blocked condensate drain 14 of the combustion chamber 8 is detected.

[0035] Fig. 2shows, by way of example and schematically, a heating device 1 proposed here. The heating device 1 can have a combustion air supply 4, to which combustion gas can be added via a gas valve 5. The resulting combustion mixture can be fed to a burner 3 arranged in a combustion chamber 8 via a mixture channel 16, in which a conveying device 2 can be arranged. Resulting combustion products can be discharged from the combustion chamber 8 via an exhaust system 9.

[0036] The heater 1 can also have a control unit 7, which can be electrically connected to an ionization electrode 13 located in the combustion chamber 8 below the burner 3. Furthermore, the control unit 7 can be electrically connected to the gas valve 5, the delivery device 2, and an ignition device 6. In an alternative embodiment, a combined ignition and ionization electrode can also be used. A method proposed here can advantageously be implemented on the control unit 7.

[0037] Fig. 3shows, by way of example and schematically, a combustion chamber 8 of a heating device 1 proposed here. Combustion mixture can be fed to the burner 3 via the mixture channel 16 and combusted to form a flame 11. The flame 11 can be monitored, for example, by means of a UV sensor 12. The combustion chamber 8 can also have an ionization electrode 13, which is also suitable for monitoring the flame 11. The UV sensor 12, burner 3, and ionization electrode 13 can be arranged in a burner door 17, which advantageously simplifies electrical cabling, for example, with a control and regulation device 7.

[0038] In the installed state, at the geodetically lowest point, the combustion chamber 8 can have a condensate drain 14, which can include a siphon 15. If the condensate drain 14 is blocked, the condensate level in the combustion chamber 8 can rise to the level of the ionization electrode 13. According to the method proposed here, the heater 1 would now detect a blockage of the condensate drain 14 based on an operating parameter, a conclusion about the voltage amplitude of the ionization electrode 13 of the flame detection.

[0039] According to an optional step d), the burner 3 of the heater 1 could be shut down after a blocked condensate drain 14 is detected in step c), thus preventing a further rise in the condensate level in the combustion chamber 8. Damage to the heater 1, in particular to the burner 3, can thus be effectively prevented. Shutting down the heater 1 can, in particular, refer to shutting down the burner 3 to prevent further condensate formation.

[0040] Fig. 4 shows an example and schematically a control circuit 18 for carrying out a method presented here and Figure 5, also schematically and by way of example, a known circuit for operating an ionization current-based flame detection system, wherein the ionization electrode 13 can simultaneously be used as an ignition electrode and an ignition circuit 29 can be connected upstream. A controller 24 is specified with a voltage amplitude for the ionization electrode 13 as the target variable 19, and feedback of the actual voltage 21 is fed to an ADC (analog-to-digital converter) input of the controller 24 via a voltage divider and evaluated in the controller 24. The controller 24 can control a switch 25 as the actuator 22 and thus an input voltage 27 transformed by a transformer 26 via a manipulated variable 20, here a PWM (pulse width modulated) signal.The AC voltage signal 23 provided by the transformer 26 and the switch 25 can be transmitted to the ignition circuit 29 via a diode 28. The ignition circuit 29 can include a capacitor charged to the amplitude of the AC voltage signal. The AC voltage signal is applied to the ionization electrode 13 via the capacitors without any DC component.

[0041] If the ionization electrode 13 comes into contact with condensate due to a blockage of the condensate drain 14 and the condensate level rises in the combustion chamber 8, an electric current can flow from the ionization electrode 13 to ground due to the conductivity of the condensate, which dampens the voltage at the ionization electrode 13 and thus at the ignition circuit 29 and the ionization electrode 13. The controller 24 detects this via the feedback of the actual voltage 21 and attempts to counteract it by changing the manipulated variable 20 in order to increase the voltage amplitude back to the specified target value 19.

[0042] In the example shown, the voltage at the ionization electrode 13, for example via the feedback of the actual voltage 21, or also the manipulated variable 20 of the controller 24, can be detected as an operating parameter that allows a conclusion to be drawn about the voltage amplitude of an ionization-based flame detection in step a).

[0043] A method presented here can advantageously be executed as a computer program on a control and regulating device 7 presented here and a device for ionization current-based flame detection known from the prior art.

[0044] The invention can in particular serve for the automatic detection of a blocked condensate drain of a heating device and is based in particular on the idea of ​​detecting a blocked condensate drain and the associated contact of an ionization electrode with condensate via an operating parameter that enables a (direct) conclusion to be drawn about the voltage amplitude applied to an ionization electrode of the flame detection. List of reference symbols

[0045] 1 Heater 2 Conveyor system 3 Burner 4 Combustion air supply 5 Gas valve 6 Ignition device 7 Control unit 8 Combustion chamber 9 Exhaust system 11 Flame 12 UV sensor 13 Ionization electrode 14 Condensate drain 15 Siphon 16 Mixture channel 17 Burner door 18 Control loop 19 Target variable 20 Control variable 21 Actual voltage feedback 22 Actuator 23 AC voltage signal 24 Controller 25 Switch 26 Transformer 27 Input voltage 28 Diode 29 Ignition circuit 30 Capacitors

Claims

1. Method for detecting a blocked condensate drain (14) of a heater (1), comprising at least the following steps: a) detecting an operating parameter of the heater which allows a voltage amplitude of an ionization electrode (13) of a flame detection system to be inferred, b) comparing the operating parameter detected in step a) with a limit value, c) recognizing a blocked condensate drain (14) from the comparison according to step b), characterized in that the operating parameter detected in step a) is a manipulated variable (20) of a control circuit (18) for keeping the voltage amplitude of an AC voltage signal (23) of the ionization electrode (13) of the flame detection system constant.

2. Method according to claim 1, wherein the operating parameter in step a) is detected via a combined ignition and ionization electrode (13).

3. Method according to any one of the preceding claims, wherein in a step d), when a blocked condensate drain (14) is recognized, a burner (3) of the heater (1) is switched off.

4. Method according to any one of the preceding claims, wherein in a step e) information about a result of the comparison in step b) or about a switch-off of the heater (1) in step d) is provided or sent.

5. Computer program comprising instructions which, when executed by a regulating and control device of a heater (1), wherein the heater comprises a condensate drain (14) and an ionization electrode (13) and the regulating and control device (7) comprises a control circuit (18) for keeping the voltage amplitude of an AC voltage signal (23) of the ionization electrode (13) constant, the heater (1) carries out a method according to any one of the preceding claims.

6. Machine-readable storage medium on which a computer program according to claim 5 is stored.

7. Regulating and control device (7) for a heater (1), wherein the heater comprises a condensate drain (14) and an ionization electrode (13), and wherein the regulating and control device (7) comprises a control circuit (18) for keeping the voltage amplitude of an AC voltage signal (23) of the ionization electrode (13) constant and is designed to cause the heater (1) to carry out a method according to any one of claims 1 to 4.

8. Heater (1) having a condensate drain (14), an ionization electrode (13), and a regulating and control device (7) according to claim 7.