EP4345379A1 - Method for starting up a heating device, control and control device, heating device and computer program - Google Patents

Abstract

A method is proposed for starting up a heating device (1) that is designed to burn a combustion mixture of combustion air and fuel gas that is fed to a burner (3) by means of a conveying device (2). The method comprises at least the following steps: a) starting up the conveying device (2) and starting up a starting speed (21), b) recording a speed curve (18, 20) of the conveying device (2) while step a) is being carried out, c) comparing the speed curve (18, 20) recorded in step b) with a reference curve (19), evaluating the speed curve (18, 20) recorded in step b), and determining a blocked condensate drain (12). The method enables a blocked condensate drain 12 to be detected/determined during a starting process of a heating device (1). In addition, a computer program, a regulating and control device (7), a heating device (1), and use of a recorded speed curve (18, 20) are proposed.

Description

The invention relates to a method for commissioning a heating device, a control device, a heating device and a computer program.

A large number of heating devices are known which burn a mixture of a fuel, in particular natural gas or hydrogen, and ambient air in a combustion chamber in order to generate heat to supply a building or to provide hot water.

When such heating devices are started up, a conveyor device is usually started up to a predetermined or specific starting power or starting speed and fuel is added to the volume flow of sucked-in combustion air that is conveyed thereby. The combustion mixture formed is fed to a burner arranged in a combustion chamber of the heater and ignited by an ignition device, for example a spark or glow igniter.

According to the state of the art, condensate that is produced during a combustion process (for example of natural gas or hydrogen) is led from the combustion chamber and the heater to a drain through a condensate drain, often comprising a siphon. A blocked drain or siphon can lead to considerable problems, even when starting up a heater. If the drain is blocked, the condensate can rise in the combustion chamber and possibly enter the burner or possibly also continue to flow into the gas supply. This can cause significant damage to the heater and require costly repairs. There are ways to detect a blocked condensate drain. However, these require the heater to be started up, which could cause damage if the condensate drain is already blocked.

For example, detecting a blocked condensate drain using ionization current-based flame detection is known, with the ionization electrode being arranged below the burner. If the condensate drain is blocked, the condensate could only collect up to the level of the ionization electrode, because when the ionization electrode comes into contact with the condensate, the ionization flow stops and the heater switches off due to a lack of flame detection. Such a solution is used, for example, in EP 3 081 861 A1 described. However, this solution cannot be used with hydrogen-operated heaters because a hydrogen flame does not release sufficient electrical charge carriers to detect an ionization current and therefore a collapse of the ionization current due to a short to ground of the ionization electrode due to an increased condensate level is not detectable. The method also cannot be used before a heater is ignited in order to avoid critical starting processes.

The DE 10 2015 206 810 A1 describes such a method in which a PWM control signal of a fan of the burner device and an ionization current of an ionization probe are detected during normal operation of a burner device in order to detect a blockage of a siphon of the burner device. The disadvantage is that the burner device must be put into operation for this purpose and, as explained above, the method cannot be used with hydrogen-operated burner devices.

In addition, mechanical options for preventing condensate build-up in a heater should be avoided. This is how it is done in the GB 2187 829A In order to prevent a blockage of a heater drain, it is proposed to collect condensate that forms in the heater in a container and then empty the entire container via the drain. The GB 249 7140 A provides for a connection piece with a switch to be provided in a condensate drain pipe, which can be activated by draining condensate within the drain pipe. By means of communication, the switch can cause another switch to switch off the heater.

These solutions are complex and/or require structural changes to a heater, which in addition to an increased probability of failure also results in increased costs for manufacturing and assembly. In addition, their use in heating devices powered by hydrogen is not easily possible or not sufficiently safe.

Based on this, it is the object of the invention to propose a method for putting a heater into operation that at least partially overcomes the problems described in the prior art. In particular, a particularly simple and universally applicable method should be proposed.

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.

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 implemented in any technologically reasonable, can be combined with one another in a similar way and define further embodiments of the invention. In addition, the features specified in the patent claims are specified and explained in more detail in the description, with further preferred embodiments of the invention being presented.

A method for commissioning a heating device contributes to this, whereby the heating device is set up to burn a combustion mixture of combustion air and combustion gas. The combustion mixture can be fed by means of a conveyor device (which can be regulated via a speed) to a burner which is arranged in a combustion chamber having a condensate drain.

1. a) Inbetriebnahme der Fördereinrichtung und Anfahren einer (vorgegebenen) Solldrehzahl;
2. b) Erfassen eines (zeitlichen) Drehzahlverlaufs der Fördereinrichtung (zumindest teilweise) während der Durchführung des Schrittes a);
3. c) Vergleichen des in Schritt b) erfassten Drehzahlverlaufs mit einem Referenzverlauf, Bewerten des in Schritt b) erfassten Drehzahlverlaufs und Feststellen eines blockierten Kondensatablaufs.

The procedure includes at least the following steps:

1. a) Starting up the conveyor device and starting up a (specified) target speed;
2. b) recording a (time) speed curve of the conveyor device (at least partially) while carrying out step a);
3. c) comparing the speed curve recorded in step b) with a reference curve, evaluating the speed curve recorded in step b) and determining a blocked condensate drain.

When carrying out the process regularly, steps a), b) and c) can be carried out at least once in the specified order; as stated, steps a) and b) can be carried out in parallel or at the same time. In particular, steps a) to c) can be carried out during or as part of every commissioning of the heater. The processes of comparing, evaluating and determining in step c) can be carried out in this order, if necessary repeated several times as part of this step c).

The method is used to ensure a safe ignition process or safe commissioning of a heater and can in particular help to detect a blocked condensate drain of a heater before fuel gas is supplied during a start-up process.

The heating device can comprise at least one heat generator, in particular a gas condensing boiler, which releases heat energy by burning a fuel and can transfer it to a heating circuit via at least one heat exchanger. A circulation pump in the heating circuit can be set up to circulate a heat transfer medium (heating water), whereby heat transfer medium heated via a heating flow can be fed to consumers, such as convectors or surface heating, and returned to the heat generator or the at least one heat exchanger via the heating return. Exhaust gases generated during combustion can be discharged to the outside via an exhaust duct of the heating device and a subsequent exhaust system.

The heater can have a conveying device, in particular a fan, which can supply a mixture of combustion air and fuel (hydrogen) to a burner of the heater. The conveying device can comprise a power control, in particular a speed controller. The heater can form a pneumatic gas-air connection in which a mass flow of combustion air is added to a mass flow of combustion gas provided via a gas supply in accordance with a negative pressure (control pressure) of a throttle point, such as a Venturi nozzle, so that a predefined (predetermined) combustion air ratio (air ratio, lambda) can be set. The heater can alternatively have an electronic gas-air connection in which a conclusion can be drawn about the flames and the combustion air ratio (also referred to as lambda or air ratio) based on a signal from a flame monitor, so that it can be regulated. The heating device can be designed in particular to burn hydrogen as fuel or a mixture containing hydrogen. The mixture can have a hydrogen content of at least 80% or at least 90%.

Condensate (liquid or watery) that is produced during the combustion of the fuel in the combustion chamber can drain from the combustion chamber of the heater via a condensate drain. The condensate drain can include a siphon that prevents gas exchange between the combustion chamber and the surrounding area. A siphon can be a mostly U-shaped pipe for the condensate drain that can fill with condensate during operation and thus prevent gas exchange, in particular the ingress of external air into the combustion chamber, through the condensate drain. The condensate can be directed to a suitable location, for example a sewer, via the condensate drain and/or the siphon.

The condensate drain can be arranged at the (geodetically) lowest point of the combustion chamber (in the operating position) to ensure that the condensate drains away as completely as possible. A blockage of the condensate drain can be caused in particular by or in the siphon. A blockage of the condensate drain can result in it being completely closed, or in such a reduced drainage speed that the condensate cannot drain away quickly enough and collects in the combustion chamber. A "blockage" is therefore understood here in particular to mean that the condensate cannot drain away or can only drain away to an insufficient extent and as a result collects or backs up (partially or to a significant extent) in the combustion chamber.

The heater can also have a flame monitor. An ionization electrode is often used for this, which can use an ionization current from the flame to detect it. However, this principle is not applicable to a hydrogen flame, cannot be used robustly, as the combustion of hydrogen produces significantly fewer free charge carriers. For this reason, other methods are often used in hydrogen-powered heaters, such as detecting the electromagnetic radiation emitted by the flame, particularly infrared (IR) and/or UV (ultraviolet) radiation, or detecting the flame temperature. A signal from a flame monitor can indicate the presence of a flame and allow conclusions to be drawn about the combustion air ratio of the flame.

The heating device can also have an ignition device which is arranged on the burner in such a way that combustion mixture emerging from the burner can be ignited. The ignition device can in particular be an electrical ignition device whose output can be controlled electrically.

Commissioning a heater can proceed as follows: First, for example a control and control device of the heater, a conveyor device, which is preferably designed as a fan, can start up or accelerate to a predetermined starting power or starting speed. After the starting power or starting speed has been reached, a safety valve in the gas supply can then be opened and gas is released. As a result, a mass flow of fuel specified for the starting speed can be added to the mass flow of combustion air conveyed by the conveying device. Through an ignition process by starting up the ignition device, a flame can be formed and the heater can be started. A method proposed here is intended to make it possible to detect a blocked condensate drain during a starting process before gas is released and thus help to avoid critical conditions caused by a starting process with a blocked condensate drain.

According to step a), the conveyor system can be put into operation and started up to a (predetermined, e.g. stored) starting speed. b. a starting speed can be specified for a speed controller of the conveyor device by the control unit of the heater.

According to step b), a (measured) recording of a speed curve of the conveyor device can take place while carrying out step a). For this purpose, a speed signal can be recorded and stored, for example, in a memory of the control unit.

According to step c), a comparison of the speed curve recorded in step b) can now take place with a reference curve, evaluation of the speed curve detected in step b) and detection of a blocked condensate drain.

A reference curve of the speed of the conveyor can, for example, be determined in advance as part of (laboratory) tests on a reference heater, and represent a speed curve on the reference heater with a (by definition) blocked and/or free condensate drain. By comparing the speed curve recorded in step a) with the reference curve, significant differences can now be identified and (as a result of the comparison) it can be determined whether a blocked condensate drain is present. As a result of the cross-sections of the flow paths of the heater changing when the condensate drain is blocked and available for gas flow, a blocked condensate drain can be reliably detected and determined based on the speed curve when the speed jumps to the starting speed when the heater is put into operation.

According to one embodiment, if a blocked condensate drain is detected, the heater can abort the starting process and refuse to release gas, i.e. not open the gas valve, in particular the gas safety valve. This can prevent a critical start process due to a blocked condensate drain.

According to one embodiment, if a blocked condensate drain is detected, the heater can be put into an error state in which restarting is blocked or can only be carried out by a qualified person. A critical ignition process can be recognized, for example, by exceeding a pressure limit in the gas supply to the heater or by a lack of or insufficient flame formation.

According to a further embodiment, information about the detection of a blocked condensate drain or about the heater being in an error state can be displayed via a display device (external or integrated in the heater) and/or made available for retrieval via a network, in particular the Internet, and/or sent as a message. For example, the information can be made available for retrieval on an appliance interface of the heater or on a network storage device (cloud). In this way, for example, a user/operator of the heater and/or a specialist company can advantageously be informed of the detection of a blocked condensate drain by means of a message and the specialist company can plan and carry out an appointment for maintenance and/or repair accordingly. In particular, this can bring about a rapid end to an error state in the heater.

According to a further aspect, a computer program is also proposed which is set up to (at least partially) carry out a method presented here. In other words, this relates in particular to a computer program (product) comprising commands which, when the program is executed by a computer or in particular a control and regulating unit of the heater, cause the computer to carry out a method proposed here. The computer program can in particular be executed on or by a control and regulating unit of the heater.

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.

According to a further aspect, a control device for a heater is also proposed, set up to carry out a method proposed here. For this purpose, the control device can, for example, have a processor and/or have one. In this context, the processor can, for example, carry out the method stored in a memory (of the control device). For this purpose, the control device can be electrically connected in particular to a conveyor device and a gas valve of the heater. In addition, data recorded or required as part of the implementation of a method proposed here can be stored in a memory of the control device, for example a speed curve recorded in step b) and/or one or more reference speed curves for carrying out step c).

According to a further aspect, a heater is also proposed, set up to burn a combustion mixture of combustion air and fuel gas, which can be fed to a burner by means of a conveying device and having means that are adapted to carry out the steps of the method proposed here. The means can include a regulating and control device. The heater can be a gas heater, in particular a hydrogen-powered gas heater. The gas heater can have a burner and a conveyor device with which a mixture of fuel (hydrogen) and combustion air can be supplied to the burner

According to a further aspect, the use of a recorded speed curve of a conveyor device of a heater to detect a blocked condensate drain of the heater is also proposed. In particular, a reference history can also be used can be used, which can be compared with the recorded speed curve in order to determine a blocked condensate drain.

The details, features and advantageous configurations discussed in connection with the method can also occur in the computer program presented here, the control device, the heater and the use and vice versa. In this respect, full reference is made to the statements there regarding the more detailed characterization of the features.

A method for starting up a heater, a control and regulating device, a heater and a computer program are therefore specified here, which at least partially solve the problems described with reference to the prior art. In particular, the method for starting up a heater, the control and regulating device, the heater and the computer program as well as the use at least help to prevent critical conditions when starting up a heater due to a blocked condensate drain.

In addition, the invention can be implemented particularly advantageously without structural changes to a heater in the form of a software implementation.

As a precaution, it should be noted that the numerals used here ("first", "second", ...) primarily serve (only) to distinguish between several similar objects, sizes or processes, and in particular do not necessarily specify a dependency and/or sequence of these objects, sizes or processes. Should a dependency and/or sequence be necessary, this is explicitly stated here or it is obvious to the expert when studying the specifically described design. As far as a component can occur multiple times ("at least one"), the description of one of these components can apply equally to all or part of the majority of these components, but this is not mandatory.

Fig. 1:

ein hier vorgeschlagenes Heizgerät,

Fig. 2:

einen Ablauf eines hier vorgeschlagenen Verfahrens, und

Fig. 3:

Parameterverläufe, die sich bei Durchführung eines hier vorgeschlagenen Verfahrens einstellen können.

The invention and the technical environment are explained in more detail below with reference to the attached figures. It should be noted that the invention is not intended to be limited by the exemplary embodiments given. 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 size relationships shown are only schematic. They show:

Fig.1:

a heater suggested here,

Fig. 2:

a procedure proposed here, and

Fig. 3:

Parameter curves that can occur when carrying out a procedure proposed here.

Fig.1 shows, by way of example and schematically, a heating device 1 proposed here. This can comprise a burner 3 arranged in a combustion chamber 8. Combustion air can be sucked in by a conveying device 2, in particular designed as a fan, via a combustion air supply 4. The conveying device 2 can be connected to a speed controller 6, which can regulate a speed n of the conveying device 2 by means of a pulse width modulated (PWM) signal. A gas valve 5 can add combustion gas from a gas supply 14 to the sucked-in air mass flow of combustion air and comprise a safety valve and a gas control valve for controlling the mass flow of combustion gas to be added. The mixture of combustion gas and combustion air produced can flow via a mixture channel 11 to the burner 3 and be ignited there by the ignition device. The burner 3 can have a cylindrical shape, which can be attached with a base to a burner door 15 in such a way that combustion mixture can flow from the mixture channel into the burner 3. After combustion, the combustion products can be discharged to the outside via an exhaust pipe 9 of the heater and an exhaust system 10. Condensate produced during combustion in the combustion chamber 8 can collect in a lower area of the combustion chamber and be discharged from the combustion chamber 8 via a condensate drain 12 of the heater 1 and fed to a drain. The condensate drain 12 can comprise a siphon 17.

The heating device 1 can also have a (device for) flame monitoring 13 on or in the burner door 15, which can be designed here as a sensor for UV (ultraviolet) radiation emitted by the flame. The flame monitoring 13 can indicate the presence of a flame or can also be used to control the combustion process.

A control and regulating device 7 can be set up to regulate the heating device 1. For this purpose, it can be electrically connected, for example, to the speed controller 6, the conveyor device 2, the gas valve 5, the flame monitor 13 and a network 16 (Internet). The control and regulating device 7 can be set up to carry out a method proposed here.

Fig. 2 shows an example and schematic of the process of a method proposed here. The implementation of steps a), b) and c) shown with blocks 110, 120 and 130 can be carried out at least once in the specified order in a regular process sequence. The process serves to increase the safety of a fuel operated, in particular with hydrogen or with a hydrogen-containing mixture, Heater 1 during commissioning or an ignition process. The method makes it possible to detect a blocked condensate drain 12 of the heater 1 during a starting process in advance of a gas release, i.e. an opening of a gas valve 5.

Fig.3 shows, by way of example and schematically, a first speed curve 18, a reference curve and a second speed curve 20 of the speed n of the conveyor device 2 of the heater 1 as a function of the time t (given in seconds) when starting up the conveyor device 2 to a starting speed 21, which in the present case can be in a range of approximately 5400 rpm [revolutions per minute]. The first speed curve 18 was recorded with a free condensate drain 12 and the second speed curve 20 with a blocked condensate drain 12. The reference curve 19 shows an expected speed curve with a free condensate drain 12. In the range of approximately 0.1 s [seconds], a speed jump to approximately 3000 rpm [revolutions per minute] can be seen in the second speed curve 20, which indicates a blocked condensate drain 12.

In block 110, according to step a), the conveyor device 2 can be put into operation and started up to a starting speed 21. Step a) can be initiated and carried out by the control device 7 of the heating device 1.

In block 120, according to step b), a speed curve 18, 20 of the conveyor device 2 can be recorded while step a) is being carried out. Step b) can also be carried out by the regulating and control device 7 of the heating device 1, wherein the recorded speed curve 18, 20 can be stored in particular in a memory of the regulating and control device.

In block 130, according to step c), the speed curve 18, 20 recorded in step b) can be compared with a reference curve 19 and the speed curve 18, 20 recorded in step b) can be evaluated. recorded speed curve based on the comparison and a blocked condensate drain 12 can be identified.???In the present case, a blocked condensate drain 12 can be identified on the second speed curve 20 based on the speed jump at approx. 0.1 s to approx. 3000 rpm. This speed jump cannot be identified on the reference curve 19 and thus represents a feature for identifying a blocked condensate drain 12.

List of reference symbols

1

heater

2

funding facility

3

burner

4

Combustion air supply

5

Gas valve

6

Speed controller

7

Control and regulation device

8th

combustion chamber

9

exhaust pipe

10

Exhaust system

11

Mixture channel

12

Condensate drain

13

Flame monitoring

14

Gas supply

15

Burner door

16

network

17

siphon

18

first speed curve

19

Reference history

20

second speed curve

21

Starting speed

Claims (8)

Method for commissioning a heating device (1) designed to burn a combustion mixture of combustion air and fuel gas, which is fed to a burner (3) by means of a conveying device (2), comprising at least the following steps: a) commissioning of the conveyor device (2) and approaching a starting speed (21); b) detecting a speed curve (18, 20) of the conveyor device (2) during the execution of step a); c) comparing the speed curve (18, 20) recorded in step b) with a reference curve (19), evaluating the speed curve (18, 20) recorded in step b) and determining a blocked condensate drain (12). Method according to claim 1, wherein when a blocked condensate drain (12) is detected in step c), a start-up process is aborted and the gas supply (14) is not released. Method according to one of the preceding claims, wherein the heater (1) is taken out of operation and brought into an error state when a blocked condensate drain (12) is detected in step c). Method according to one of the preceding claims, wherein information about a detected blocked condensate drain (12) in step c) and/or about the heater (1) being put into a fault state is displayed via a display device, made available for retrieval via a network (16) and/or sent by means of a message. Regulating and control device (7) configured to carry out a method according to one of claims 1 to 4. Heater (1), set up for burning a combustion mixture of combustion air and fuel gas, which can be fed to a burner (3) by means of a conveying device (2) and having means which are adapted to carry out the steps of the method according to one of claims 1 to 4 execute. Computer program comprising instructions which cause the heating device (1) of claim 6 to carry out the method steps according to one of claims 1 to 4. Use of a detected speed curve (18, 20) of a conveying device (2) of a heater (1) for detecting a blocked condensate drain (12) of the heater (1).

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