Method and device for identifying liquid in a blower of a heating device and computer program product

Abstract

The present invention relates to a method for identifying the presence of liquid (15) in a blower (4) of a heating device (1) that operates by means of a mixture of air and fuel gas, which is delivered by the blower (4) to a burner (2), wherein at least one physical quantity characterizing the function of the blower (4) is measured at least once at predetermined time intervals after the start-up of the heating device (1) and compared with empirical values ​​and / or calibration data, and the deviation (d1, d2, d3) from the empirical values ​​and / or calibration data is evaluated as an indication of liquid (15) in the blower (4) when the deviation (d1, d2, d3) from the empirical values ​​and / or calibration data reaches a predetermined amount. The corresponding device has a control and regulation unit (5) for accelerating the blower (4) with a pulse width modulation current and processing the measured actual value of the speed (D) of the blower (4). A comparator (12) is present in the control and regulation unit (5) and is configured to compare the speed (D) and / or the pulse width of the pulse width modulation current with stored empirical values, and to trigger an alarm or fault message when the deviation (d1, d2, d3) reaches a predetermined amount. This invention enables early and reliable determination of the presence of liquid in the blower without additional instruments in the heating equipment, thereby preventing subsequent damage.

Description

Technical Field

[0001] The present invention relates to a method and apparatus for identifying the presence of liquid in the blower of a heating device that operates by a mixture of air and fuel gas. Background Technology

[0002] Modern heating equipment, especially so-called condensing combustion equipment, operates using a premixed burner. In this system, air is first mixed with a specific amount of fuel gas suitable for clean combustion, and then a blower delivers the resulting mixture to the burner. The burner distributes the mixture into the combustion chamber, where combustion forms a flame. The resulting exhaust gases are discharged through an exhaust gas treatment system. For fuel gases containing hydrogen or hydrocarbons, water vapor is also produced during combustion. This water vapor condenses at various points within the heating equipment along with other possible components. Check valves, typically located in the exhaust gas treatment system, prevent water vapor or condensate from entering the blower. This is particularly useful for multiple distribution systems where multiple heating units are connected to a chimney.

[0003] However, under higher safety standards, early identification of water, condensate, or other liquids, such as those caused by check valve malfunctions, in the blower of such heating equipment is necessary or at least desirable, as these liquids in the component and adjacent components can lead to corrosion and other malfunctions. However, such identification has not yet been provided in heating equipment. This safety benefit is particularly desirable in multi-distribution systems.

[0004] To start the heating equipment, the control and regulation unit typically initiates all associated processes, including increasing and accelerating the blower's speed to a predetermined rating. For this purpose, one to three phases of alternating current are supplied to the blower, the effective value of which is predetermined by pulse width modulation (a so-called PWM signal). The control and regulation unit receives a measurement of the current blower speed and can then adjust the blower speed to its rated value. Summary of the Invention

[0005] The object of the present invention is to at least alleviate the problems explained with reference to the prior art, and especially to identify the presence of liquid in a blower by means of a control and regulation unit that is generally used to provide existing data and measurements without additional instruments, which can be used, for example, to trigger alarm or fault information, or to initiate maintenance when necessary.

[0006] A method for identifying the presence of liquid in a blower of a heating device achieves this purpose, wherein the heating device operates by means of a mixture of air and fuel gas, the mixture being delivered to a burner by the blower. Therefore, at least one physical quantity characterizing the function of the blower is measured at least once at predetermined time intervals elapsed since the start-up of the heating device, and compared with (known, determined, and / or stored) empirical values ​​and / or calibration data, wherein a deviation from the empirical values ​​and / or calibration data reaching a predetermined amount (or predetermined degree) is assessed as an indication of liquid in the blower. The (known, determined, and / or stored) empirical values ​​and / or calibration data particularly include observed values ​​and / or curves characterizing the physical quantity, wherein (in fact) no liquid is present in the blower and no (significant) amount of liquid is present, wherein, if necessary, one or more limit values ​​for determining the amount of liquid may also be present. For example, empirical values ​​and / or calibration data may also exist as characteristic curves depending on the operating state of the heating device, environmental conditions, the location of the blower, etc. To date, it remains inconclusive whether the presence of a (small amount) of liquid in the blower (i.e., typically at the bottom of the blower casing) affects the blower's intended function, and therefore, it is not expected that measurements of blower function can prove the presence of liquid in the blower and distinguish it from other effects. However, precise measurements suggest that this is surprisingly the case. The liquid in the casing exhibits characteristics distinct from other malfunctions or operational variations, as will be explained below with several examples. In particular, where necessary, the conclusion of the presence of liquid in the blower can be definitively reached through one or more additional elimination methods (e.g., based on further evaluation of the same or at least one other / additional physical quantity).

[0007] "Physical quantity" here should be understood as any measurable characteristic or quantity, or any (derived from it) operating parameter, or any (derived from it) state quantity that can describe the state and / or performance of the blower, i.e., in particular, quantities such as rotational speed, effective power consumption, mass flow, pressure difference, flow rate, temperature, noise level, etc. "Empirical values" can be preset and / or stored, especially for heating equipment, for example, as the result of long-term testing or long-term observation of the operation of such heating equipment. "Calibration data" can be set or determined, for example, when the heating equipment is set up (for the first time); calibration data can involve values ​​that enable specified or efficient operation under field conditions. The "predictable amount" of deviation can include fixed predetermined values ​​or values ​​that can be variably adapted to operating conditions if necessary. It is possible that an alarm and / or safety action will be (directly) generated in the heating equipment or the control and regulation unit of the heating equipment when the deviation is determined to reach at least a predictable amount.

[0008] Studies have shown that acceleration becomes difficult when there is liquid in the blower, and therefore the rotational speed increases more slowly than when there is no liquid. Accordingly, a larger pulse width is required for acceleration over a longer period compared to the case without liquid. Other physical quantities characterizing blower function exhibit similar behavior. This invention utilizes this to check the presence of liquid in the blower (which has not been systematically measured or recorded to date) each time the heating equipment is started or when it is expected to participate in the start-up of the heating equipment.

[0009] In a particularly simple embodiment of the invention, the physical quantity is determined and compared exactly once only at a critical time point after startup, such as 0.1 to 2 seconds after startup, preferably 0.3 to 1.5 seconds after startup. For greater accuracy, multiple measurements and comparisons can also be performed at intervals. If the deviation from calibration data or empirical values ​​is, for example, greater than 10% (an example of a predetermined amount), this can be systematically interpreted as an indication of the liquid.

[0010] Particularly preferably, (not just at a single point in time, but) from the start-up of the heating equipment, a time curve characterizing at least one physical quantity of the blower's function is measured and observed, and compared with empirical values ​​and / or calibration data, wherein when the deviation of the curve from the empirical values ​​and / or calibration data reaches a predetermined amount, that deviation is assessed as an indication of the liquid in the blower. Continuous or quasi-continuous observation of the time curve improves accuracy and helps avoid misunderstandings.

[0011] The speed of the blower is particularly suitable as a physical quantity to be observed. Measurements are taken for all modern heating equipment, and these measurements are always available to the control and regulation units. This allows the measurements to be used not only for known adjustments but also to determine the presence of liquid in the blower without the need for additional instrumentation.

[0012] Another suitable physical quantity is the pulse width of the pulse-width modulated current (typically a 1-phase or 3-phase AC current) transmitted to the blower by the control and regulation unit after the heating equipment is started. Simply put, pulse width modulation (PWM) means rapidly turning on and off at a variable rhythm (e.g., at 1 kHz [kilohertz] or higher), where the ratio between the on-time (pulse width) and off-time is changed (modulated). This ratio is also called the duty cycle and can also be given as a percentage. A 100% duty cycle means the current is continuously on, while a 50% duty cycle means the current is only on for half the time.

[0013] Preferably, an alarm or fault message is triggered when liquid is indicated in the blower. This can be signaled audibly via a signaling device, or optically via a display or indicator (e.g., an alarm light), or sent to an external location to trigger maintenance. In this way, liquid in the blower or adjacent components (e.g., gas valves) can be prevented from causing damage through corrosion or leading to unpredictable conditions in the heating equipment.

[0014] On the other hand, a device for identifying the presence of liquid in the blower of a heating device is proposed, wherein the heating device operates by means of a mixture of air and fuel gas, the mixture being delivered to the burner by the blower. A control and regulation unit is provided, configured to control the start-up of the blower and the increase of its speed up to a rated value using pulse-width modulated current, and to process the measured actual value of the speed. The control and regulation unit includes at least one comparator configured to compare the speed and / or the pulse width of the pulse-width modulated current with stored calibration data and / or empirical values, and to trigger an alarm or fault message when the deviation reaches a predetermined amount. A typical control and regulation unit for such a heating device has a data memory for calibration data and / or empirical values, and at least one microprocessor, allowing the control and regulation unit to take over the described additional functions with minimal effort. The blower speed and the PWM signal for controlling the blower are also always available.

[0015] Preferably, the comparator is configured to perform comparisons not only at a single point in time after the heating equipment starts, but also at multiple points in time after the heating equipment starts, or quasi-continuously. In this way, higher accuracy in data interpretation can be achieved, thereby reducing the likelihood of erroneous alarm messages or fault messages (false alarms).

[0016] On the other hand, it relates to a computer program product comprising instructions that cause the device to perform the method. The comparison of measured data with empirical or calibration data requires programs and data for the control and regulation unit of the heating equipment, both of which must be updated from time to time. Such a computer program product can achieve this.

[0017] An explanation of the method can be used to characterize the device in more detail, and an explanation of the device can be used to characterize the method in more detail. The device can also be configured to perform the method. Attached Figure Description

[0018] The illustrative embodiments of the invention (however, the invention is not limited thereto) and the operating modes of the method will now be explained in more detail with reference to the accompanying drawings. Wherein:

[0019] Figure 1The illustration schematically depicts a typical heating device with a correspondingly designed control and regulation unit; and

[0020] Figure 2 This diagram illustrates the speed and PWM signal behavior of the blower when the heating equipment is started, with and without liquid present. Detailed Implementation

[0021] Figure 1 A typical heating device 1 (e.g., a so-called condensing combustion device) is schematically shown, which can operate using a mixture of air and fuel gas. A blower 4 draws in ambient air, which is mixed with a predetermined amount of fuel gas suitable for clean combustion via a fuel gas valve 6. The mixture is conveyed from the blower 4 through a mixture conduit 7 to the burner 2 and burned in the combustion chamber 3. Exhaust gas is discharged through an exhaust pipe 10 with a check valve 11. A central control and regulation unit 5 controls and regulates the heating device. This also includes controlling the blower 4 via a signal line 8 with a pulse width modulation current (PWM signal) when the heating device 1 is started, and monitoring the blower speed D via a measuring line 9 during start-up and acceleration, so as to quickly increase the speed D to a predetermined rated value and adjust it thereafter. It has been shown that, under such conditions, the presence of liquid 15 in the blower 4 (e.g., at the bottom of the blower housing) can also be determined without additional internal components or instruments. For this purpose, the control and regulation unit 5 has a comparator 12 and at least one data storage unit 13 for calibration data and / or empirical values. After the heating device 1 is started, the comparator can compare the curve of the time-dependent speed D and / or PWM signal after startup with a stored or predetermined curve (calibration data). In this case, the liquid 15 in the blower causes very typical deviations (d1, d2, d3), which can be interpreted as an indication of the presence of liquid 15 starting from a predetermined amount (e.g., exceeding 5%, preferably exceeding 10%) of the stored value at any given time point. In this case, it may be sufficient to determine the deviation at only one appropriate time point, but more reliable results are obtained when comparing two or more time points, especially when comparing values ​​measured continuously or over short time intervals (quasi-continuously). When the presence of liquid 15 in the blower is indicated, the control signal device 14 and / or otherwise triggers an alarm or fault message, especially to a remote location, for example, to trigger maintenance.

[0022] Figure 2The diagram illustrates the curves of the rotational speed D and the PWM signal during the first 2 seconds after the heating device 1 is started. Time t is plotted on the X-axis, rotational speed D (revolutions per second) is plotted on the left side of the Y-axis, and the magnitude of the PWM signal is plotted as a percentage on the right side. The solid line corresponds to the curve of the PWM signal when there is no liquid 15 in the blower 4. To achieve a rapid increase in the rotational speed D (dashed line) of the blower 4, a continuous current (100% duty cycle) is first sent for 0.5 seconds. If operation is undisturbed, the PWM signal may decrease because the rotational speed D has rapidly approached its rated value (constant speed in the graph). This can be identified by the drop in the previously constant PWM signal. Conversely, if there is liquid 15 in the blower 4, a different curve for the rotational speed D and the PWM signal is obtained. The dashed line shows the curve of the PWM signal that occurs subsequently, where the PWM signal clearly shows a drop in the constant signal only afterward. The deviation d3 (here exceeding 0.4 seconds) can therefore be used as an indication of the presence of liquid 15 in the blower 4. The performance of the rotational speed D also differs in the presence of liquid (dotted line). The rotational speed D rises more slowly and, for example, reaches only about 3500 instead of 5000 after 0.5 s, which can be determined by comparator 12 as deviation d1. Tests even show that when the rotational speed D rises above the set rating, before the rating is slowly set (in this case 6000), for example, after about 1.4 s, the undisturbed curve rises above 7500 (not 6000), resulting in deviation d2. It can be seen that the liquid 15 in the blower 4 can be determined very reliably by the comparator 12 according to the invention.

[0023] This invention allows for the early and reliable determination of the presence of liquid in a blower in a heating device without additional instruments, thereby preventing subsequent damage.

[0024] List of reference numerals

[0025] 1. Heating equipment

[0026] 2. Burner

[0027] 3 Combustion Chamber

[0028] 4. Blower

[0029] 5. Control and Regulation Unit

[0030] 6. Gas valve

[0031] 7. Mixture Pipeline

[0032] 8 signal lines (PWM signal)

[0033] 9. Measuring line (speed)

[0034] 10 Exhaust pipe

[0035] 11 Check valve

[0036] 12 Comparators

[0037] 13 Data Storage

[0038] 14. Signal equipment

[0039] 15 Liquid

[0040] D rotational speed

[0041] t time

[0042] d1 First deviation (speed)

[0043] d2 Second deviation (speed)

[0044] d3 Third Deviation (PWM Signal)

Claims

1. A method for identifying the presence of liquid (15) in a blower (4) of a heating plant (1) which is operated by means of a mixture of air and a fuel gas containing hydrogen or hydrocarbons, which mixture is delivered by the blower (4) to a burner (2), wherein At least one of the following physical quantities characterizing the function of the blower (4) is measured at least once during a predetermined time interval elapsed since the start of the heating device (1): the time for increasing the blower speed and / or the blower speed and / or the pulse width of the pulse width modulated current supplied to the blower (4), and compared with at least empirical values ​​or calibration data, and the deviation between the physical quantity and the at least empirical values ​​or calibration data is evaluated as an indication of liquid (15) in the blower (4) when the deviation of the physical quantity from the at least empirical values ​​or calibration data reaches a predetermined amount, and an alarm message or fault message is triggered; wherein, firstly, a continuous current is supplied to the blower (4) to reach a set speed, and if the speed of the blower exceeds the set speed by more than 5% before the duty cycle of the current pulse width switches to less than 100%, it is evaluated as an indication of the presence of liquid (15) in the blower (4).

2. The method according to claim 1, wherein, The time curve of the physical quantity is measured and observed from the start of the heating device (1) and compared with at least empirical or calibration data, and the deviation of the curve from the curve of at least empirical or calibration data is evaluated as an indication of the liquid (15) in the blower (4) when the deviation of the curve from the curve of at least empirical or calibration data reaches a predetermined amount.

3. The method according to claim 1 or 2, wherein, In order to achieve the set speed, a continuous current is first supplied to the blower (4), and the time deviation between the measured value of the pulse width modulation signal curve and at least the empirical value or calibration data is determined until the duty cycle of the current pulse width switches to less than 100%.

4. The method according to claim 1 or 2, wherein, To achieve the set speed, a continuous current is first supplied to the blower (4), and then the time deviation between the measured value of the pulse width modulation signal curve and at least the empirical value or calibration data is determined before the set speed is reached.

5. An apparatus for performing a method according to any one of the preceding claims for identifying the presence of liquid (15) in a blower (4) of a heating device (1), said heating device being operated by means of a mixture of air and a fuel gas containing hydrogen or hydrocarbons, said mixture being supplied by said blower (4) to a burner (2), wherein, The device is provided with a control and regulation unit (5), which is configured to control the start-up of the blower (4) and the increase of the speed (D) of the blower by means of pulse width modulation current and to process the measured actual value of the speed (D). The control and regulation unit (5) is provided with a comparator (12), which is configured to compare the speed (D) and / or the pulse width of the pulse width modulation current with stored calibration data and / or empirical values, and to trigger an alarm or fault message when the deviation reaches a predetermined amount.

6. The apparatus according to claim 5, wherein, The comparator (12) is configured to perform comparisons at least at multiple time points or quasi-continuously after the heating device (1) is started.

7. A computer program product comprising instructions that cause the apparatus according to any one of claims 5 to 6 to perform the method according to any one of claims 1 to 4.

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