EP4273407A1 - Method for detecting damage to a fan casing of a heating device, computer program product, control device, heating device and use of a detected value - Google Patents

Abstract

A method is presented for detecting damage to a housing (8) of a fan (2) of a heater (1), wherein the fan (2) supplies a mixture of air and fuel gas to a burner (3) of the heater (1), and at least a variable (20) dependent on the condition of the housing (8) is detected and if the variable (20) exceeds or falls below a limit value (21, 22), it is concluded that there is damage to the housing (8). The at least one recorded variable (20) can in particular be - a determined mass flow or volume flow of the blower (2), - a power consumption of the blower (2), - a thermal output of the heater (1), - a heat-up time of a heater (1) connected heating water circuit (14), and / or - a differential pressure between two points upstream and downstream of the fan (2).

Description

The invention relates to a method for detecting damage to a housing of a fan of a heater, a computer program product, a control and control device, a heater and a use of a detected variable.

In heating devices, sensors are generally used, e.g. B. used for temperature, light or heat radiation, pressure, volume flow and the like to regulate the heating devices and ensure their safe operation. One important task is to determine the presence of stable flames (a so-called flame monitor), another is to set a ratio of combustion air to fuel gas (lambda value) that is suitable for stable and environmentally friendly combustion. Design and control measures are also taken to prevent so-called flame flashbacks from a combustion chamber in which combustion is intended to take place into the supply system of still unburned mixture of air and fuel gas. Nevertheless, such events, which can have different causes and processes, cannot be completely ruled out, especially when using fuel gas containing hydrogen, which causes higher flame speeds and releases more energy per volume than conventional fuel gas mixtures.

In the event of a flashback or back-ignition, a pressure surge occurs in the supply system, which can propagate into a fan that conveys the mixture of air and fuel gas. This can cause an impeller (possibly made of plastic) to be deformed, particularly due to heat generated at the same time. The consequences can be even more serious if a flashback also ignites the mixture in the blower housing. A pressure surge can then spread far into the housing and deform its walls or cause leaks to the environment. Typical blower housings are made of die-cast and/or sheet metal parts, where joints, welds or connections in particular can be damaged by a pressure surge.

The object of the present invention is to detect damage to the housing of the fan of a heating system, in particular caused by previous flashbacks (possibly not registered by a conventional sensor system), in order to be able to take suitable safety measures if necessary.

In addition, the invention should at least not significantly increase the complexity of a heater and only require minor structural changes to the device and enable simple integration into an existing production process.

These tasks are solved by the features of the independent patent claims. Further advantageous embodiments of the solution proposed here are specified in the independent patent claims. It should be noted that the features listed in the dependent patent claims can be combined with one another in any technologically sensible manner and define further embodiments of the invention. In addition, those specified in the patent claims Features are specified and explained in more detail in the description, with further preferred embodiments of the invention being presented.

A method for detecting damage to a housing of a fan of a heater contributes to solving the problem, the fan supplying a mixture of air and fuel gas to a combustion chamber of the heater, and at least one variable dependent on the condition of the housing is detected and when reached (in particular If a limit value is exceeded and/or fallen short of, the size indicates damage.

The heater is in particular a gas heater that is designed to burn a fuel gas (for example natural gas or hydrogen) while supplying ambient air and to generate thermal energy, for example to heat a heat transfer medium in a heating circuit or to provide a hot water supply. In particular, the heater can be a condensing boiler. The heater usually has a combustion chamber and a fan that can convey a mixture of fuel gas and combustion air into a combustion chamber. The combustion products can then be removed through an exhaust system.

A burner can be arranged in the combustion chamber, often comprising perforated sheets that can be flat, curved or cylindrical. The mixture of fuel gas and combustion air can flow through the perforated sheets and then be ignited and burned. If the flame speed of the combustion is greater than the outflow speed of the mixture, a flame flashback can occur in the line paths of the mixture of fuel gas and combustion air. A Such a problem can also occur during an ignition process, or if the temperature of the perforated sheet metal on the side facing away from the combustion chamber is higher than the side facing the combustion chamber.

As a result of the flame flashback or back-ignition described, the line paths of the mixture of fuel gas and combustion air, as well as the impeller of the blower and the blower itself, can be damaged. The invention serves in particular to detect damage to the housing of the blower, in particular damage that allows external air to enter and/or the mixture of fuel gas and combustion air to escape, in other words a leak in the housing. As a result of a flashback, damage to the housing on the pressure side of the blower often occurs, which can result in the mixture of fuel gas and combustion air escaping. In other words, a method is particularly specified here which detects the ingress of external air and/or the escape of fuel gas and/or combustion air from the blower housing and/or a leakage/leakage of the blower housing. In particular, it is possible to distinguish such damage to the housing of the blower from, for example, other damage such as unexpected flow bottlenecks, blockages, etc.

According to an advantageous embodiment, if an upper or lower limit value is exceeded, damage can be concluded from the detected size. The upper and lower limit values can indicate or limit a reference range of the size to be detected, from which it can be concluded that the housing is intact. By including an upper and lower limit The security of a method proposed here can be increased, although this should be assessed with regard to the specific quantity to be recorded.

According to an advantageous embodiment, the variable dependent on the condition of the housing can in particular be at least one of the following.

The variable, which depends on the condition of the housing, can be a flow rate (gas volume flow or gas mass flow) in the line path to the burner. This can be determined, for example, by a flow sensor (air mass flow sensor). If the blower housing is defective (leaking), the pressure loss that the blower has to overcome decreases and therefore a larger flow rate can be conveyed at the same speed of the housing. This means that if a limit value is exceeded, it can be concluded that the housing is damaged.

However, if the housing is significantly damaged and pressure can no longer be built up by the impeller, a very low flow rate can occur at the same speed. Therefore, according to a further advantageous embodiment, even if the flow rate falls below a lower limit, it can be concluded that the housing is damaged.

The variable that depends on the condition of the housing can be an electrical power consumption of the fan. This can be done, for example, by detecting a control signal, in particular a PWM signal (pulse width modulated signal). A PWM signal can, for example, be specified as a percentage of the fan's rated power. This can result in a defective housing and an associated sinking Pressure loss of the same leads to a lower power consumption of the fan and thus to a lower limit value being undershot.

However, as already explained above, if the housing is significantly damaged and pressure can no longer be built up by the impeller, a very high power consumption can also occur, as the control system tries to regulate to a nominal volume flow, but this is due to the damage to the Housing cannot be reached. Damage to the housing can therefore also be indicated by exceeding an upper limit of the power consumption of the fan.

• mit P_th ... thermische Leistung
• ṁ ... Massestrom Wärmeträger
• c_p ... spezifische Wärmekapazität Wärmeträger, und
• T_Vor, T _Rück ... Vorlauf - und Rücklauf temperatur

The variable that depends on the condition of the housing can (preferably) also be a thermal output of the heater. If the housing of the heater's fan is damaged, the amount of gas supplied can decrease due to a lower control pressure on the mixing unit (for example a Venturi device) and thus the thermal output of the heater. The thermal output of the heater can be determined, for example, based on a recorded flow and return temperature of the heater:
$$P_{\mathit{th}}=\dot{m}\times c_p\times \left(T_{\mathit{Before}}-T_{\mathit{back}}\right)$$

• with P _th ... thermal power
• ṁ ... mass flow of heat transfer medium
• c _p ... specific heat capacity heat carrier, and
• T _forward , _{back ...} flow and return temperature

A thermal performance of the heater determined in this way can be compared with a thermal performance that is expected based on the fan speed and, in the event of a deviation (outside a tolerance range), in particular if the thermal performance falls below the expected thermal performance, it can be concluded that the housing of the fan is damaged.

The variable that depends on the condition of the housing can (preferably) be a heating-up time of a heating water circuit. The heating water circuit can be a heating circuit connected to the heater, in which a heat transfer medium can circulate. Advantageously, the heating water circuit can be closed in particular via a heat exchanger arranged in the heater for the provision of hot water, since with such a heater-internal heating circuit there is good comparability of a determined heating time due to the absence or only minor external influences. If the housing is damaged and, as described above, the associated decreasing thermal performance of the heater, the heating time of the heating water circuit (for a defined temperature difference) can be extended and thus the expected heating time can be exceeded as a limit value.

The variable dependent on the condition of the housing can (preferably) be a differential pressure, which is determined at two points on the line paths for fuel gas or combustion air in the direction of flow in front of and behind the fan. For this purpose, for example, pressure sensors can be arranged at two corresponding points.

According to an advantageous embodiment, several variables can also be recorded and, if necessary, evaluated, so that other circumstances that lead to a limit value of a variable being exceeded or fallen short of are excluded.

Advantageously, the variables mentioned are often recorded in heating devices as part of the regulation and control, which makes it possible to implement the invention as a pure software implementation.

According to an advantageous embodiment, in addition to the variable dependent on the condition of the housing, a speed of the fan can be recorded and the at least one limit value can be given as a function of the speed of the fan.

According to an advantageous embodiment, continued operation and/or ignition of the heating system can be prevented (automatically) if the detected variable has exceeded or fallen below at least one limit value. In other words, if damage to the housing of the fan of the heater is detected, the operation of the heater can be stopped and restarting can be prevented, so that this can only be carried out by a person who is familiar with the system.

According to an advantageous embodiment, information about a detected damaged housing can be displayed via a display device and/or made available for retrieval via a network and/or sent as a message. The display device can be a display device of the heater or that of a (wirelessly) connected device, for example a mobile phone. The network can in particular be the Internet. An operator or a supporting specialist company can advantageously be informed by a message via the network or by providing the information and can independently plan and carry out a service appointment.

According to a further aspect, a computer program is also proposed which is used to (at least partially) carry out a method presented here is set up. In other words, this applies in particular to a computer program (product), comprising instructions which, when the program is executed by a computer, cause it to carry out a method proposed here.

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 regulating and control device of a heater (in particular as disclosed here) is also proposed, set up to carry out a method proposed here. For this purpose, the control and control device can, for example, have and/or have a processor. In this context, the processor can, for example, execute the method stored in a memory (of the control device). Advantageously, operating data (for example (upper and/or lower) limit values of the recorded variable(s)) can also be stored in the memory of the control device in order to carry out a method presented here. In addition, the regulating and control device can be set up to record the variable that depends on the condition of the housing of the fan of the heater.

According to a further aspect, a heater (in particular as disclosed here) is also proposed, having a regulating and control device proposed here.

• ein stromabwärts des Gebläses ermittelter Volumenstrom
• eine Leistungsaufnahme des Gebläses,
• eine thermische Leistung des Heizgerätes,
• eine Aufheizzeit eines mit dem Heizgerät verbundenen Heizungswasserkreislaufes,
• ein Differenzdruck zwischen zwei Punkten stromaufwärts und stromabwärts vom Gebläse

zum Erkennen einer Beschädigung eines Gehäuses eines Gebläses eines Heizgerätes, vorgeschlagen. Ganz besonders erfolgt die Verwendung derart, dass eine Beschädigung aufgrund eines Flammenrückschlages oder einer Rückzündung schnell erkannt und ggf. Sicherungsmaßnahmen ergriffen werden. Es ist auch möglich, dass damit auch das Erkennen eines Flammenrückschlages oder einer Rückzündung identifiziert oder bestätigt werden kann.According to a further aspect, a use of a recorded quantity is selected from:

• a volume flow determined downstream of the fan
• a power consumption of the blower,
• a thermal output of the heater,
• a heating-up time of a heating water circuit connected to the heater,
• a differential pressure between two points upstream and downstream of the blower

for detecting damage to a housing of a fan of a heater, proposed. In particular, it is used in such a way that damage due to flashback or re-ignition is quickly recognized and, if necessary, safety measures are taken. It is also possible that this can also be used to identify or confirm the detection of a flashback or re-ignition.

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

Here, a method for detecting damage to a housing of a fan of a heater, a computer program (product), a control and control device, a heater and a use of a detected variable are specified, which solve the problems described with reference to the prior art at least partially solve. In particular, the method for detecting damage to a housing of a fan of a heater, the computer program product, the control and control device, a heater and the use of a detected variable at least contribute to a simple and safe way to detect damage to a housing of a fan of a heater and thus make the operation of a heater safer.

In addition, the invention can be implemented particularly easily and cost-effectively, since generally only an adaptation of computer software is necessary. The invention is therefore also suitable for retrofitting existing heating devices.

Fig. 1:

ein hier vorgeschlagenes Heizgerät, und

Fig. 2-5:

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

The invention and the technical environment are explained in more detail below using the accompanying 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 proportions shown are only schematic. Show it:

Fig. 1:

a heater proposed here, and

Fig. 2-5:

Parameter curves that can arise when carrying out a method proposed here.

Fig. 1 shows an example and schematic of a heater 1 proposed here. This can have an air supply 4 for combustion air, in which a mass flow sensor 16 can be arranged for measuring the sucked in mass flow of combustion air. A venturi device 15 can be arranged in the air supply 4, which produces a quantity of gas corresponding to a control pressure generated by the mass flow of combustion air attached. A fuel gas valve 5 can also be arranged in the supply of the fuel gas.

Seen in a flow direction 18 of the air supply 4, downstream of the Venturi device 15, a blower 2 can be arranged with a housing 8, which can supply the mixture of fuel gas and combustion air to a burner 3 via a mixture channel 12. The fan 2 can be connected to a speed control 19. A heat exchanger 13 can be arranged on the burner 3 and can transfer the heat generated during combustion to a heating water circuit 14. The heating water circuit 14 can include a flow 26 with a temperature sensor 6 and a return 27 with a temperature sensor 11, via which consumers such as radiators or surface heating can be connected. The heating circuit 14 can be closed by means of a three-way valve 24 via a heat exchanger 25 arranged between the flow 26 and return 27 to provide hot water, with a heating time of the heating circuit 14 closed via the heat exchanger 25 being very comparable, since no or only minor external influences have an effect. A mass flow sensor 9 can also be arranged in the heating water circuit 14, which can detect the mass flow of heat transfer medium (usually heating water).

Downstream of the burner 3, an exhaust pipe 10 can feed resulting combustion products to an exhaust system. A control and control device 7 of the heater 1 can be connected to the speed control 19 of the fan 2, the fuel gas valve 5, the mass flow sensor 16 in the air supply 4, the mass flow sensor 9, the temperature sensor 6 in the flow, the temperature sensor 11 in the return of the heating water circuit 14, the Three-way valve 24 and a network 17 (in particular the Internet) can be electrically connected.

Fig. 2 shows exemplary and schematic parameter curves of a mass flow ṁ combustion air as a function of time t, determined by the mass flow sensor 16 in the air supply 4 of the heater 1 when the heater 1 is started. A detected variable 20 lies between a lower limit value 21 and an upper limit value 22, whereby an intact housing 8 of the blower 2 can be recognized.

Fig. 3 shows, by way of example and schematically, parameter curves of an electrical power consumption P _el as a function of the time t at a constant speed of the blower 2. The detected variable 20 lies between a lower limit value 21 and an upper limit value 22, with which an intact housing 8 of the blower 2 can be recognized .

Fig. 4 shows an example and schematic of parameter curves of a thermal power P _th depending on the time t at a constant speed n of the fan 2. The thermal power can be determined based on the relationship P _th = ṁ × c _p × ( T _forward - T _back ). The recorded variable 20 (or determined thermal power) is above a lower limit value 21, which means that here too it can be concluded that the housing 8 of the blower 2 is intact.

Fig. 5 shows, by way of example and schematically, parameter progressions of a heating time t until a target temperature 23 of the heating water circuit 14 is reached. A recorded variable 20 (detected heating time) is below an upper limit value 22, which means that here too it can be concluded that the housing 8 of the fan 2 is intact.

Reference symbol list

1

heater

2

fan

3

burner

4

Air supply

5

Fuel gas valve

6

Flow temperature sensor

7

Control and control device

8th

Housing

9

Mass flow sensor domestic hot water circuit

10

exhaust pipe

11

Return temperature sensor

12

Mixture channel

13

Heat exchanger

14

Heating water circuit

15

Venturi device

16

Mass flow sensor air supply

17

network

18

Direction of flow

19

Speed control

20

recorded size

21

lower limit

22

upper limit

23

Target temperature

24

Three-way valve

25

Heat exchanger for hot water provision

26

leader

27

Rewind

Claims (14)

Method for detecting damage to a housing (8) of a fan (2) of a heater (1), the fan (2) supplying a mixture of air and fuel gas to a burner (3) of the heater (1), and at least one of the condition The size (20) dependent on the housing (8) is detected and when a limit value (21, 22) is reached, the size (20) indicates that the housing (8) is damaged. Method according to claim 1, wherein the damage is a deformation and/or a leakage of the housing (8) to the environment. Method according to one of the preceding claims, wherein when an upper limit value (22) or lower limit value (21) is reached, the detected variable (20) indicates damage to the housing (8) of the blower (2). Method according to claim 3, wherein in addition to the variable (20) dependent on the state of the housing (8), a speed of the fan (2) is recorded and an upper limit (22) and/or lower limit (21) is given depending on the speed . Method according to one of the preceding claims, wherein the detected variable (20) is at least one of the following variables (20), which are dependent on the speed of the fan (2): - a determined mass flow or volume flow of the fan (2), - a power consumption of the blower (2), Method according to one of the preceding claims, wherein the detected variable (20) is a thermal output of the heater (1). Method according to one of the preceding claims, wherein the detected variable (20) is a heating time of a heating water circuit (14) connected to the heater (1). Method according to one of the preceding claims, wherein the detected variable (20) is a differential pressure between two points upstream and downstream of the fan (2). Method according to one of the preceding claims, wherein further operation and/or ignition of the heater (1) is prevented when the detected variable (20) has reached a limit value (21, 22). Method according to one of the preceding claims, wherein information about a detected damaged housing (8) is displayed via a display device and/or made available for retrieval via a network (17) and/or sent as a message. Computer program product comprising instructions which cause a method according to one of the preceding claims to be carried out. Regulating and control device (7) of a heater (1), wherein a fan (2) supplies a mixture of air and fuel gas to a burner (3) of the heater (1), set up to carry out a method according to one of claims 1 to 10. Heater (1), comprising a fan (2), which can supply a mixture of air and fuel gas to a burner (3) of the heater (1), with a control and control device (7) according to claim 12. Use of at least one recorded size (20) selected from: - a volume flow or mass flow determined downstream of the blower (2), - a power consumption of the blower (2), - a thermal output of the heater (1), - a heating time of a heating water circuit (14) connected to the heater (1), and/or - a differential pressure between two points upstream and downstream of the blower (2) to detect damage to a housing (8) of a fan (2) of a heater (1).

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