PROCEDURE FOR TESTING AN EXHAUST SYSTEM OF A HEATER

Description

[0001] The invention relates to a method for testing an exhaust system of a heater, a computer program, a control unit and a heater.

[0002] For safety reasons, combustion monitoring is required for gas-fired heaters according to EN 15502-2-1.

[0003] If the flow resistance of the exhaust system increases, for example, due to excessive contamination, a heater must be blocked from starting up to prevent carbon monoxide from escaping. As part of the mandatory monitoring of combustion products, a heater should shut itself down when a certain amount of carbon monoxide is present in the exhaust gas, and restarting should be blocked.

[0004] For this purpose, DE 10 2008 006 120 A1 proposes specifying a target power consumption and a permissible deviation range of the same for a combustion air supply arrangement during operation of a heater with a target heating output. If a (detected) comparative power consumption lies outside the permissible deviation range of the target power consumption, a blockage condition can be assumed in the combustion air flow path and / or the exhaust gas flow path of the heater. However, if the method described therein were implemented, an increase in flow resistance would possibly only be detected after the heater has been put into operation.

[0005] EP 1 519 113 A2 proposes a method for adapting the heating output of a fan-assisted heater to the individual pressure losses of a fresh air-exhaust duct system. For this purpose, a fan speed and fan power are recorded, and the power consumed at a specified speed is compared with a reference value. A disadvantage of this method is that it is not sufficiently precise, and a fan failure can lead to unsafe operating conditions of the heater.

[0006] In the method proposed in EP 2 469 168 A1 for operating a gas burner for a heating device, a current fan speed is also monitored via the current voltage signal of the fan and compared with a predetermined target fan speed or with a target voltage signal.

[0007] A method for detecting a blockage in an exhaust gas duct is proposed in EP 3 260 777 A1. This involves using a pressure value that contains information about the pressure within the exhaust gas duct. The pressure value can be determined, for example, using a pressure sensor in the exhaust gas duct. The disadvantage is that a pressure sensor must be installed in the exhaust gas duct, which is expected to have a short service life due to the high temperatures and corrosive conditions in the exhaust gas duct.

[0008] Based on this, the object of the invention is to provide a method for testing an exhaust system of a heater that enables reliable detection of an increased flow resistance of an exhaust system.

[0009] In addition, the process should be easy to implement and not significantly increase the complexity of a heating device.

[0010] 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.

[0011] The method proposed here is particularly suitable for use with a heater with a pneumatic gas-air connection. Unlike an electronic gas-air connection, gas valve tolerances in a pneumatic gas-air connection cannot be compensated for by a control system.

[0012] The method according to the invention for testing an exhaust system of a heater comprises at least the following steps: a) Starting up a fan as the gas delivery device of the heater and increasing the power of the gas delivery device, b) Recording a feed parameter characterizing the flow of the gas stream in the gas supply of the heater, c) Recording a power parameter characterizing the implemented power of the gas delivery device when a feed reference value of the feed parameter recorded in step b) is reached, d) Enabling the heater for commissioning if the power parameter characterizing the implemented power of the gas delivery device is lower than a power reference value of the gas delivery device when the feed reference value is reached, wherein the feed parameter is determined by a pressure sensor arranged in the gas supply, a pressure switch whose threshold value corresponds to the feed reference value and which switches a gas valve of the heater,or a flow sensor and the performance parameter is a speed of the gas delivery device and the performance reference value is a reference speed. ,

[0013] During normal operation, steps a), b), and c) are carried out at least partially in parallel, followed by step d). The execution of step a) can be terminated after the feed reference value has been reached in step c).

[0014] The solution proposed here describes, in particular, a particularly simple and reliable method for detecting excessive flow resistance in the exhaust system of a heater, combined with the possibility of blocking the heater from starting up in the event of increased flow resistance. Advantageously, the method can be easily and automatically implemented each time a heater is started, requiring only minor structural changes to the heater.

[0015] In addition, the method enables testing of the flow resistance of an exhaust system of a heater in operation.

[0016] In step a), a fan acting as the gas delivery device of the heater is started up and the output of the gas delivery device is increased. A gas delivery device is capable of delivering a gas stream. Heaters, particularly heaters with a pneumatic gas-air system, generally already have a gas delivery device for supplying the gas mixture to be burned. This existing gas delivery device can be advantageously used to implement the method proposed here.

[0017] According to a further advantageous embodiment, the gas delivery device is controlled such that the power increase corresponds to a ramp function. The ramp can have a ramp start value for the power of the gas delivery device, for example, a ramp start speed, which is then continuously increased.

[0018] In step b), a feed parameter characterizing the gas flow rate in the gas supply of the heater is recorded. In other words, the feed parameter is a measure of the volume flow conveyed by the gas delivery device.

[0019] The supply parameter characterizing the gas flow in the heater's gas supply can, in particular, be a pressure in the heater's gas supply determined by a pressure sensor. Advantageously, the pressure can be easily determined.

[0020] According to an advantageous embodiment, the pressure, as a supply parameter characterizing the flow of the gas stream in the gas supply of the heater, can be determined by a pressure sensor in the silencer of the air intake of the heater. This is advantageously particularly easy to implement.

[0021] In an alternative embodiment, the supply parameter characterizing the gas flow in the gas supply of the heater could also be a volume flow determined, for example, by a flow sensor. The flow sensor can be arranged, for example, in the air intake of the heater.

[0022] In a step c), a performance parameter characterizing the converted performance of the gas delivery device is recorded when a feed reference value of the feed parameter recorded in step b) is reached.

[0023] In a step d), the heater is now released for commissioning if the performance parameter characterizing the performance of the gas delivery device is lower than a reference value of the performance parameter of the gas delivery device when the feed reference value is reached.

[0024] The feed reference value can be a value determined in advance for the specific heater, which indicates a sufficiently low flow resistance of the exhaust system, provided that the performance parameter characterizing the converted power of the gas feed device is lower than a performance reference value of the performance parameter.

[0025] An alternative embodiment of the method comprises at least the following steps: a1) Starting up a fan as the gas delivery device of the heater and increasing the power of the gas delivery device up to a power reference value, b1) Recording a feed parameter characterizing the flow of the gas stream in the gas supply of the heater, c1) Enabling the heater for commissioning when a feed reference value of the feed parameter recorded in step b1) is reached, wherein the feed parameter is determined by a pressure sensor arranged in the gas supply, a pressure switch whose threshold value corresponds to the feed reference value and which switches a gas valve of the heater, or a flow sensor and the power parameter is a speed of the gas delivery device and the power reference value is a reference speed.

[0026] According to step a1) of the alternative embodiment of the method, the performance of the gas production facility is increased up to a performance reference value.

[0027] In a step b1), a feed parameter characterizing the flow of the gas stream in the gas supply of the heater is recorded.

[0028] According to step c1), the heater is released for commissioning when a feed reference value of the feed parameter recorded in step b) is reached.

[0029] In this alternative embodiment of the method, steps a1), b1) and c1) are carried out at least partially in parallel or simultaneously.

[0030] In a preferred embodiment of the method, the supply parameter characterizing the flow of the gas stream in the gas supply of the heater can be a pressure determined in the gas supply, wherein the pressure is determined by a pressure switch whose threshold value corresponds to the supply reference value and which switches the gas valve of the heater. This embodiment is particularly suitable for the alternative embodiment of the method for carrying out step c1). An advantage of this embodiment lies in a particularly simple and thus safe implementation of the method.

[0031] According to an advantageous embodiment of the method, the supply of combustion gas can be blocked during the process, for example, by a closed gas valve. This advantageously prevents the escape of combustion gas or exhaust gas and the associated hazards during the process.

[0032] According to an advantageous embodiment of the method, the gas delivery device can be a fan. Increasing the performance of the fan according to this embodiment can consist of increasing the fan speed. The performance parameter characterizing the converted power of the gas delivery device can be the fan speed, and the reference power according to steps a1) and d) of the alternative embodiment can be a reference speed of the fan.

[0033] According to a further advantageous embodiment of the method, if the implementation has not resulted in the heater being released for commissioning, the method can be carried out again.

[0034] According to a further advantageous embodiment of the method, startup of the heater is blocked after a defined number of process runs without the heater being enabled. This effectively prevents operation of the heater with an increased flow resistance of the exhaust system. The defined number of process runs until startup is blocked can be, for example, three. By repeatedly executing the proposed method, incorrect detection of a high flow resistance of the exhaust system can be advantageously largely excluded.

[0035] According to a preferred embodiment of the method, the gas valve for supplying the combustion gas is opened and an ignition process is initiated as part of the release of the heater.

[0036] According to a further advantageous embodiment of the method, when the heater is in operation, the heater is decommissioned in a step f) if a function of a performance parameter characterising the performance of the gas production facility is greater than a performance reference value, or a performance parameter characterising the performance of the gas production facility is greater than a function of a performance reference value.

[0037] This additional method step enables testing of the flow resistance of the heater's exhaust system while the heater is in operation. In a preferred embodiment, the function of the performance parameter characterizing the performance of the gas delivery device and / or the function of the performance reference value is a linear function or a factor. A factor can be determined, for example, as the quotient between a determined performance value and the performance reference value. The determined performance value is the measured power (in particular fan speed) when the supply reference value is reached each time the heater is started up when heat is requested during operation.

[0038] After decommissioning the heater in step f), the proposed procedure can be performed again. In the event of increased flow resistance in the exhaust system, commissioning can be blocked after a defined number of process runs have been completed without the heater being released for commissioning.

[0039] 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.

[0040] According to a further aspect, a machine-readable storage medium on which the computer program is stored is also proposed.

[0041] The machine-readable storage medium is usually a computer-readable data carrier.

[0042] According to a further aspect, a control unit for a heater is also proposed, configured to carry out a method presented here. For this purpose, the control unit can, for example, have or be equipped with a processor. In this context, the processor can, for example, execute the method stored in a memory (of the control unit).

[0043] According to a further aspect, a heater with a control device presented here is also proposed. The heater is, in particular, a gas heater with a pneumatic gas-air connection. The heater can have a device for detecting a supply parameter characterizing the flow of the gas stream in the gas supply of the heater, for example, a pressure sensor or a flow sensor. In a preferred embodiment, the heater has a pressure sensor in a silencer of the gas supply.

[0044] The use of a heater for testing the flow resistance of a heater's exhaust system is advantageous. This particularly relates to the use of a supply parameter characterizing the flow of the gas stream in the heater's gas supply, for example, a pressure or a volume flow, which is preferably measured in the heater's gas supply, and to the use of a performance parameter characterizing the converted power of the gas delivery device, in particular the speed of a fan representing the gas delivery device.

[0045] Thus, a method for testing an exhaust system of a heater, a computer program, a control unit, and a heater are specified here, which enable a safe and simple testing of the exhaust system of a heater for increased flow resistance. In a particularly advantageous manner, a heater can be blocked from being started up using the method proposed here if the exhaust system is blocked. Likewise advantageously, only very minor changes to the configuration of a heater according to the prior art are necessary to enable implementation of the method according to the invention. Last but not least, the method can be carried out fully automatically, for example by a control unit before each start-up of the heater, thereby eliminating human error.

[0046] The invention and the technical environment will now be explained in detail with reference to the figures. The figures show exemplary embodiments to which the invention is not intended to be limited. They schematically depict: Fig. 1: a sequence of a method proposed here, Fig. 2: a sequence of an alternative embodiment of a method proposed here, Fig. 3: a heating device proposed here, and Fig. 4: a diagram illustrating the parameters used in the method proposed here.

[0047] Fig. 1 shows, by way of example and schematically, a sequence of a method proposed here. The method is used to test the exhaust system of a heater 1. In particular, it can be checked whether an exhaust system of the heater 1 has increased flow resistance, i.e., whether it is at least partially blocked. The heater 1 can be a gas-powered heater 1 with a pneumatic gas-air connection.

[0048] The sequence of steps a), b), c), d), e, and f) illustrated by blocks 110, 120, 130, 140, 150, and 160 can occur during normal operation. For example, when switching on heater 1, the procedure can be usefully performed to check the functionality of the exhaust system before commissioning. The gas valve of heater 1 can preferably be closed during the procedure to increase safety.

[0049] In a block 110, according to step a), a gas delivery device 13 of the heater 1 is started up and the power of the gas delivery device 13 is increased. A control unit 14 of the heater 1 starts the gas delivery device 13, which can be designed as a fan, and increases its power, i.e., increases the speed of the fan. The increase in the power of the gas delivery device 13 occurs within the power spectrum of the gas delivery device 13 and is thus aborted when the maximum power of the gas delivery device 13 is reached.

[0050] In parallel with increasing the performance of the gas delivery device 13, a supply parameter characterizing the flow rate of the gas stream in the gas supply of the heater is detected in block 120 according to step b). The supply parameter characterizing the flow rate of the gas stream in the gas supply of the heater can, for example, be a pressure detected in the silencer 11 by means of a pressure sensor 12.

[0051] Likewise, in parallel, in block 130 according to step c), a performance parameter characterizing the performance of the gas delivery device is recorded when a feed reference value of the feed parameter recorded in step b) is reached. The performance parameter characterizing the performance of the gas delivery device can be the speed of a fan that represents the gas delivery device. The feed reference value can be a value determined in advance for the specific heater.

[0052] Once the feed reference value is reached, steps a) and b) can be aborted.

[0053] In block 140), according to step d), the performance parameter recorded in step c) characterizing the performance of the gas delivery device can now be compared with a reference value of the performance parameter of the gas delivery device when the supply reference value is reached. If the performance parameter of the gas delivery device 13 is above the reference value of the performance parameter, a restart of the process is initiated by the control unit 14 according to path 141. The same applies if the maximum performance of the gas delivery device 13 has been reached without the supply reference value being reached.

[0054] For example, after three process runs without reaching the feed reference value or if the performance parameter detected in step b) is higher than the reference value of the performance parameter, step e) is carried out in block 150 according to path 143, after which the heater 1 is blocked. The blocking of the heater 1 can be designed such that it can only be terminated by a service technician and not by the user himself.

[0055] If, in step d), the performance parameter recorded in step b) is higher than the reference value of the performance parameter, heater 1 is enabled for commissioning. The control unit 14 then preferably automatically performs the start-up process of heater 1.

[0056] With heater 1 in operation, step f) can be performed in block 160. Step f) serves to test the flow resistance of the exhaust system during heating operation. For this purpose, a performance parameter characterizing the performance of the gas delivery device and a final output can be used. The two values ​​are linked and compared using a calculation operation. Thus, in step f), a comparison is made as to whether a function of a performance parameter characterizing the performance of the gas delivery device is greater than a final output, or whether a performance parameter characterizing the performance of the gas delivery device is greater than a function of a final output. If the final output or the function of the final output is exceeded, heater 1 is taken out of operation. According to path 161, control unit 14 can initiate a repeat execution of steps a) - d) after heater 1 has been taken out of operation.

[0057] The function of the performance parameter characterizing the performance of the gas delivery system or the function of the final output can consist of a factor. The factor can be determined, for example, by a quotient of the performance parameter when the heater starts up during operation (when heat is requested) and the reference output.

[0058] Fig. 2 also shows, by way of example and schematically, a sequence of an alternative embodiment of a method proposed here. This alternative embodiment of the method also serves to test an exhaust system of a heater 1. In particular, it can be checked whether the exhaust system of the heater 1 has an increased flow resistance, i.e., whether it is at least partially blocked. The heater 1 can be a gas-powered heater 1 with a pneumatic gas-air connection.

[0059] In block 210, according to step a1), a gas delivery device 13 of the heater 1 is started up, and the power of the gas delivery device 13 is increased up to a final power. A control unit 14 of the heater 1 can start the gas delivery device 13 for this purpose. The gas delivery device 13 can also be designed as a fan here, and the increase in power can consist of an increase in the speed. The power of the gas delivery device 13 is increased up to a final power, i.e., up to a final speed.

[0060] In parallel, in block 220, corresponding to step b1), a feed parameter characterizing the flow of the gas stream in the gas feed of the heater 1 is recorded.

[0061] As soon as the feed parameter detected in step b1) reaches a feed reference value in block 130 according to step c1), the heater 1 can be released for commissioning according to path 231.

[0062] If the feed reference value is not reached before the final power is reached in step a1), the process can be repeated according to path 232. If the process has already been run several times, for example three times, without the heater 1 being released for commissioning, step e) can be carried out according to path 233, in which the heater 1 is blocked from commissioning.

[0063] After the heater 1 has been released for commissioning in step c1), step f) can be carried out analogously to the design of the method according to Fig. 1 take place.

[0064] Fig. 3 shows, by way of example and schematically, a heater 1 proposed here. This can have a gas conveying device 13, which is preferably designed as a fan. A silencer 11 can be arranged downstream of the air conveying device, viewed in the direction of air flow. A pressure sensor 12 can be arranged within the silencer 11, which measures the pressure in the air intake as a supply parameter characterizing the flow of the gas stream in the gas supply of the heater 1.

[0065] The heater 1 may have a control unit 14 which is configured to carry out the method proposed here and is electrically connectable to the pressure sensor 12.

[0066] Fig. 4 shows an example diagram to illustrate the parameters used in the method proposed here. The x-axis of the diagram shown corresponds to the performance parameter characterizing the performance of the gas delivery device 13. For example, the performance parameter is a speed of a fan representing the gas delivery device, which is specified here in revolutions per minute. The y-axis of the diagram shown corresponds to the supply parameter characterizing the flow of the gas stream in the gas supply of the heater 1, which, for example, is the pressure measured in the silencer 11 of the heater 1 by a pressure sensor 12 and specified in Pascal.

[0067] In Fig. 4 a reference curve 31 is shown, which represents the pressure in the silencer 11 with increasing power (speed) of the gas conveying device 13 when the exhaust system is undisturbed.

[0068] A horizontal line shows the supply reference value 5. In the present example, this is 59 Pa. A vertical line shows the final power 4 of the gas delivery device 13, which in this case is 1600 revolutions per minute. The reference curve 31 reaches the supply reference value 5 at a point 51. The power (rotational speed) of the gas delivery device 13 is below the final power 4 at point 51, and the heater 1 can therefore be started because no increased flow resistance could be detected in the exhaust system.

[0069] A first measurement curve 32 shows the same relationship with a slightly increased flow resistance of the exhaust system, whereby the required power (rotational speed) of the gas delivery device 13 is greater to overcome the increased flow resistance. The first measurement curve 32 reaches the supply reference value 5 at a point 52, whereby the associated power (rotational speed) of the gas delivery device 13 is below the final power 4. Thus, the heater 1 can also be approved for commissioning for the first measurement curve 32, since safe operation of the heater 1 is ensured despite the slightly increased flow resistance.

[0070] A second measurement curve 33 shows the same relationship with a significantly increased flow resistance of the exhaust system. The second measurement curve 33 reaches the supply reference value 5 at a power (speed) of the gas delivery device 13 that exceeds the final power 4. Thus, the detected flow resistance of the exhaust system is too high, and the heater 1 is not enabled for commissioning.

[0071] A procedure proposed here according to Fig. 1 would recognize in step d) that the performance parameter characterizing the converted power of the gas delivery device 13 is greater than the power reference value 4 of the gas delivery device 13 when the supply reference value 5 is reached and would not indicate approval for commissioning of the heating device 1.

[0072] A procedure proposed here according to Fig. 2When carrying out step a), the power of the gas feed device 13 would increase to the power reference value 4 without the feed reference value 5 being reached and therefore would also not indicate approval for commissioning of the heater 1. List of reference symbols

[0073] 1Heater 11Silencer 12Pressure sensor 13Gas delivery device 14Control unit 31Reference curve 32First measurement curve 33Second measurement curve 4Power reference value 5Feed reference value

Claims

1. Method for testing an exhaust system of a heating appliance (1) comprising at least the following steps: a) starting up a fan as a gas conveying device (13) of the heating appliance (1) and increasing the output of the gas conveying device (13), b) detecting a feed parameter characterising the flow rate of the gas flow in the gas feed of the heating appliance (1), c) detecting a performance parameter characterising the performance of the gas feed device (13) when a feed reference value (5) of the feed parameter detected in step b) is reached, d) enabling the heating appliance (1) for commissioning if the power parameter characterising the converted power of the gas feed device (13) is lower than a power reference value (4) of the power parameter of the gas feed device (13) when the feed reference value (5) is reached, wherein the feed parameter is determined by a pressure sensor (12) arranged in the gas feed, a pressure switch whose threshold value corresponds to the feed reference value (5) and which switches a gas valve of the heating appliance (1), or a flow sensor, and the power parameter is a rotational speed of the gas feed device (13) and the power reference value (4) is a reference rotational speed.

2. Method for testing an exhaust system of a heating appliance (1) comprising at least the following steps: a1) Starting up a fan as a gas conveying device (13) of the heating appliance (1) and increasing the power of the gas conveying device (13) up to a power reference value (4), b1) detection of a feed parameter characterising the flow rate of the gas flow in the gas feed of the heating appliance (1), c1) enabling the heating appliance (1) for commissioning when a feed reference value (5) of the feed parameter detected in step b) is reached, wherein the feed parameter is determined by a pressure sensor (12) arranged in the gas feed, a pressure switch whose threshold value corresponds to the feed reference value (5) and which switches a gas valve of the heating appliance (1), or a flow sensor, and the power parameter is a rotational speed of the gas feed device (13) and the power reference value (4) is a reference rotational speed.

3. The method according to any one of the preceding claims, wherein the method is performed again if no release of the heating appliance (1) has been achieved.

4. Method according to claim 3, wherein after carrying out a defined number of process runs without enabling the heating appliance (1), the heating appliance (1) is blocked for commissioning.

5. Method according to one of the preceding claims, wherein when the heating appliance (1) is released, a gas valve of the heating appliance (1) is opened and an ignition process takes place.

6. Method according to one of the preceding claims, wherein in a step e) after commissioning of the heating appliance (1) in the event that a function of a power parameter characterising the power of the gas delivery device (13) is greater than a power reference value (4) of the power parameter, or a performance parameter characterising the performance of the gas conveying device (13) is greater than a function of a performance reference value (4) of the performance parameter, the heating appliance (1) is taken out of operation.

7. Method according to one of the preceding claims, wherein the supply parameter detected in step b) is a pressure in the gas supply of the heating appliance (1) determined by a pressure sensor (12).

8. Method according to claim 7, wherein the pressure sensor (12) is arranged in a silencer (11) of the air intake of the heating appliance (1).

9. Method according to one of claims 7 or 8, wherein the pressure sensor (12) is a pressure switch that switches a gas valve of the heating appliance (1).

10. Heating appliance (1), comprising a gas feed device (13) and an exhaust gas system as well as means for detecting a feed parameter in a gas feed of the heating appliance and means arranged for carrying out a method according to one of claims 1 to 9.

11. A control device (14) for a heating appliance (1) according to claim 10, adapted to perform a method according to any one of claims 1 to 9.

12. A computer program comprising instructions which cause a heating appliance according to claim 10 or a control device according to claim 11 to perform a method according to any one of claims 1 to 9.

13. Machine-readable storage medium on which the computer program according to claim 12 is stored.