METHOD FOR LEAK TESTING AN EXHAUST SYSTEM OF A HEATING UNIT

Description

[0001] The invention relates to a method for leak testing an exhaust system of a heater, a computer program, a machine-readable storage medium, a heater and a use of a conveying device.

[0002] Before heating systems are commissioned, the associated flue system is subjected to a leak test. Any leaks could lead to the escape of combustion gases, for example, into enclosed spaces, and thus endanger people. The use of low-temperature or condensing technology has further increased the need for leak testing. Since the flue gases in such systems have a low temperature and therefore only little energy to escape to the outside via a chimney or flue pipe, fans are used, which create overpressure within the flue system. This overpressure would lead to increased gas leakage at a leak in the flue system.

[0003] A leak test is typically performed by sealing the exhaust system gas-tight around its outlet and then applying pressure. The pressure in the pressurized exhaust system is measured using a pressure gauge, with the detected pressure drop within a defined test period providing a measure of the exhaust system's leak-tightness.

[0004] Special testing equipment is usually used for pressure generation and measurement, and adapters are often required to adapt the testing equipment to the heating or exhaust system being tested. This means that several devices must be available for a leak test on a heater's exhaust system, and connecting them and conducting the test involves considerable expense and labor. This can be particularly disadvantageous for exhaust systems that require frequent leak testing.

[0005] CN 208 060 103 U proposes a device for testing a motor vehicle exhaust system. The device includes a connection for a compressed air source and a connection for the exhaust system itself. After applying a test pressure to the exhaust system to be tested, an air flow is detected, which is crucial for determining the leak. This solution is disadvantageously complex, as the device, along with a compressed air source, must be transported to the heating system's installation location.

[0006] Based on this, the object of the invention is to provide a method for leak testing an exhaust system of a heater that at least partially overcomes the described problems of the prior art and, in particular, reduces the number of devices required for the leak test. Furthermore, a computer program, a control device, and a heater, as well as a use of the heater, are to be specified to achieve these objects.

[0007] In addition, the workload for leak testing of a heater's exhaust system and the associated costs should be reduced.

[0008] 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.

[0009] A method for testing the leak tightness of an exhaust system of a heater contributes to this, which comprises at least the following process steps: a) gas-tight sealing of the exhaust system in the area of ​​the outlet opening, b) commissioning of a conveying device for conveying a combustible mixture within the heater, which is arranged upstream of the exhaust system in the direction of flow, into a defined operating state, c) recording the gas flow conveyed by the conveying device, d) comparing the gas flow recorded in step c) with a reference value and determining the tightness of the exhaust system.

[0010] Steps a) - d) are carried out at least once in the specified order. In particular, it is conceivable that steps b), c), and d) are carried out at least partially in parallel. The further (optional) steps of the method can also be carried out sequentially according to their designation or at least partially superimposed on one another (including steps b) - d). The method can also be carried out using a heating device likewise described here. Preferably, a control and regulating device of a heating device is configured to carry out the method according to the invention.

[0011] The terms flow direction and downstream are used here in relation to the flow direction of the gas flow in the exhaust system or in the heater when the heater is in operation.

[0012] The method proposed here describes, in particular, a possibility for an automated or partially automated leak test of a heater's exhaust system, which largely eliminates the possibility of a faulty leak test due to human error. A particular advantage of the method is that it requires little effort to perform and can therefore be repeated with little effort after the installation of a new heater or maintenance work on the heater or the exhaust system. Since the same devices located in the heater are used for each leak test, excellent comparability of the results of multiple, spaced-apart leak tests is also ensured.

[0013] In step a), a gas-tight seal is created so that no exhaust gas can normally reach or flow through an open end of the heater's exhaust system. The open end here refers to the end of the exhaust system facing away from the burner or heater. In a very simple version, this is achieved by inserting an expandable element, such as an inflatable sealing balloon, which, once expanded, seals the exhaust system gas-tight. The open end of the exhaust system can, but does not have to, coincide with the area of ​​the outlet opening. The area of ​​the outlet opening can be any point within the exhaust system or in the flow path of the exhaust gas. It is understood that only the area of ​​the exhaust system up to the point at which it is sealed is included in the leak test. Other sealing options, such as applying a blind plug, are also conceivable.

[0014] In one embodiment, an automated closure element could be provided, for example, a controllable closure flap or a (heat-resistant) expandable element that remains in the exhaust system and is activated by a control signal, then closing the exhaust system. An automated closure element would open up the possibility of a fully automated leak test.

[0015] In step b), a conveying device for conveying a combustible mixture within the heater, which is arranged upstream of the exhaust system in the direction of flow, is started up to a defined operating state. The defined operating state later enables comparison with a reference value coordinated with the defined operating state. By operating in the defined operating state, the conveying device applies a defined test pressure to the exhaust system. In a preferred embodiment, the conveying device is a blower or fan. The conveying device is preferably arranged upstream of the burner of the heater, as seen in the direction of flow, whereby the tightness of the burner or combustion chamber is included in the leak test. It is also possible to integrate a conveying device between the burner and the exhaust system, whereby the conveying device is designed according to the thermal loads.

[0016] In a preferred embodiment, the conveying device is a blower, and the defined operating state is a defined speed of the blower. A particular advantage of this embodiment is its simple and cost-effective implementation.

[0017] The conveying device is a device for conveying a combustible mixture within the heater. This can be advantageously implemented particularly in heaters with condensing technology and offers the advantage that no separate conveying device is required for the leak test; instead, a conveying device already present in the heater can be used for the proposed method. In particular, the conveying device for conveying a combustible mixture within the heater is a fan, which is preferably operated at a defined speed as a defined operating state.

[0018] In step c), the gas flow conveyed by the conveying device is recorded. Recording can begin during the start-up of the conveying device (step b), but the process should not be continued until a steady state has been reached. The conveyed gas flow corresponds to the gas flow escaping downstream of the conveying device through leaks and thus represents a measure of the tightness of the test section between the conveying device and the point at which the exhaust system was sealed in step a).

[0019] According to a preferred embodiment, detection is carried out using a gas flow sensor. With such a gas flow sensor, the mass flow and / or volume flow of the gas flow can be determined (directly or indirectly) at predetermined times or (cumulatively) over a period of time. This sensor is preferably arranged in the air supply to the burner of the heater, in particular the air intake pipe. On the side of the air supply to the burner, only a gas flow corresponding to the gas flow escaping in the test section is conveyed, in particular after performing step b).

[0020] In step d), the gas flow measured in step c) is compared with a reference value. The reference value was preferably determined in advance for the exhaust system with the defined operating state of the conveying device. If the measured gas flow is above the reference value, the exhaust system is leaking; if the measured gas flow is below or equal to the reference value, the leak test is considered passed.

[0021] In an optional process step e), the result of the comparison from step d) can now be displayed on a suitable display device. Examples of suitable display devices include colored signal lights, a loudspeaker, and / or a digital display device, which advantageously also allows for the numerical display of the measured gas flow and / or reference value. Alternatively, the test result could also be transmitted wirelessly to a data processing system or displayed on a display device on the heater.

[0022] In a further optional procedural step f), if a leaky exhaust system is detected in step d), commissioning of the heater could be prevented. This additional procedural step can prevent the operation of a heater with a leaky exhaust system and damage caused by ignoring the leak test results.

[0023] According to a preferred embodiment, steps e) and f) are carried out at least temporarily in parallel, particularly preferably simultaneously.

[0024] 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.

[0025] According to a further aspect, a machine-readable storage medium on which the computer program is stored is also proposed.

[0026] The machine-readable storage medium is usually a computer-readable data carrier.

[0027] A control and regulating device of the heater is configured to carry out a method presented here. For this purpose, the control and regulating device 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 and regulating device). The reference value is preferably stored in the same memory. Furthermore, the control and regulating device can advantageously access a display device, which is already present in most heaters, to display the test results according to step e). Last but not least, step f), preventing the heater from being started up by the control and regulating device of the heater, is also easy to implement.

[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 and combustion air (combustible mixture) to a gas burner.

[0029] According to a further aspect, the use of a heater for leak testing of an exhaust system of the heater is also proposed. In particular, the use of a conveying device for conveying a combustible mixture into a burner of the heater to build up pressure for leak testing of an exhaust system of the heater is proposed.

[0030] Thus, a method for leak testing of an exhaust system of a heater, a computer program and a heater for implementing the method, and a use of a conveying device are provided here, which at least partially solve the problems described with reference to the prior art. In particular, the method, the computer program and the heater, as well as the uses, each contribute at least to simplifying the leak test and reducing costs. Furthermore, the high degree of automation of the proposed method can largely eliminate faulty tests, thus increasing operational reliability.

[0031] The invention will now be explained in detail with reference to the figures. They depict: Fig. 1: a sequence of a method proposed here, and Fig. 2: a heating device proposed here.

[0032] Fig. 1shows an exemplary and schematic sequence of a method proposed here. The method allows the leak test of an exhaust system of a heater. Process steps a) to f) are represented by blocks 110, 120, 130, 140, 150, and 160.

[0033] In block 110, the open end of the exhaust system is sealed gas-tight according to step a). In block 120, after step b), a conveying device is started up and run up to a defined operating state. In block 130, according to step c), the gas flow conveyed by the conveying device is recorded and subsequently compared with a reference value in block 140 according to step d). The result of the comparison represents the result of the leak test and is simultaneously output via a display device in block 150 (step e)). If the result of the leak test is negative, commissioning of the heater is blocked in block 160 according to step f).

[0034] Fig. 2 shows an example of a heating device 1 according to the invention. This has a burner 3, to which a combustible gas mixture is made available via an air intake pipe 4 and a gas supply pipe 8, which is supplied via a conveying device 2, which is designed here as a fan. The gas flow conveyed by the conveying device 2 can be detected by a gas flow sensor 6. A gas valve 5, which can interrupt the gas supply, is arranged in the gas supply pipe 8. The heating device 1 also has a regulating and control device 7, which is electrically connected to the gas valve 5, the gas flow sensor 6, the conveying device 2 and the burner 3. An exhaust system 10, which discharges the combustion gases from the burner 3 to the outside, is arranged downstream of the burner 3.

[0035] The Figure 1The method shown is stored as a computer program in a memory in the control and regulating device 7, as is the reference value used in block 140 (step d)).

[0036] According to block 110 (step a)), the exhaust system 10 is sealed gas-tight at its open end by means of a sealing balloon 9. After step b) shown in block 120, the conveying device 2, designed here as a blower, is now driven by the control unit 7 to a defined speed, thus applying a test pressure to the exhaust system 10 and the burner 3.

[0037] After the value returned by the gas flow sensor 6 has reached a steady state, this value is detected by the control unit 7 according to step c) shown in block 130. Subsequently, the control unit 7 compares the detected gas flow with the reference value stored in the memory according to block 140 (step d)).

[0038] If the measured gas flow is higher than the reference value, there is a leak in exhaust system 10 or burner 3. If the measured gas flow is less than or equal to the reference value, the leak test is defined as passed.

[0039] The result is now displayed in block 150 according to step e) by the control unit 7 via a display device of the heater 1 (not shown in detail here). If the detected gas flow is higher than the reference value and a leak has thus been detected, the control unit 7 also blocks the start-up of the heater 1. List of reference symbols

[0040] 1Heater 2Feeding device 3Burner 4Air intake pipe 5Gas valve 6Gas flow sensor 7Regulating and control unit 8Gas supply pipe 9Sealing balloon 10Exhaust system

Claims

1. Method for testing the tightness of an exhaust system (10) of a heating appliance (1), comprising at least the following steps: a) gas-tight sealing of the exhaust system (10) in the region of an outlet opening, b) bringing into operation a conveyor apparatus (2) for conveying a combustible mixture within the heating appliance (1), which conveyor apparatus is arranged upstream of the exhaust system (10) in the flow direction, into a defined operating state, c) detecting the gas stream conveyed by the conveyor apparatus (2), d) comparing the detected gas stream with a reference value to ascertain the tightness of the exhaust system (10).

2. Method according to claim 1, wherein the result of step d) is output on an optical and / or acoustic display apparatus.

3. Method according to any of the preceding claims, wherein in a further method step f) the bringing into operation of the heating appliance (1) is prevented when it is ascertained in step d) that the exhaust system (10) is untight.

4. Method according to any of the preceding claims, wherein in step c) the detection is carried out by means of a gas stream sensor (6).

5. Method according to any of the preceding claims, wherein in step b) the conveyor apparatus (2) is in the form of a blower and the defined operating condition is a defined speed of the blower.

6. Method according to any of the preceding claims, wherein in step a) the exhaust system (10) is sealed in a gas-tight manner by means of an automated sealing element (9).

7. Heating appliance (1) having a conveyor apparatus (2) for conveying a combustible mixture into a burner, wherein the conveyor apparatus (2) is in the form of a blower, characterized by an optionally automated sealing element (9) for gas-tight sealing of an exhaust system (10) of the heating appliance (1) in the region of an outlet opening, and a closed-loop and open-loop control appliance (7) designed to perform at least steps b) - d) of a method according to any one of claims 1 to 6.

8. Computer program comprising commands that cause a heating appliance (1) according to claim 7 to carry out a method according to any one of claims 1 to 6.

9. Machine-readable storage medium on which the computer program according to claim 8 is stored.

10. Use of a conveyor apparatus (2) for conveying a combustible mixture into a burner (3) of a heating appliance (1) according to claim 7 in order to build up pressure for the tightness testing of an exhaust system (10) of the heating appliance (1).