GAS DEVICE

Description

[0001] The invention relates to a gas measuring device, a tester for a gas measuring device and a test method for testing a gas measuring device.

[0002] Gas measuring devices, especially gas warning devices with a gas sensor, must undergo functional tests at regular intervals to ensure their correct functionality.

[0003] During the operation of a gas measuring device, the functionality of the gas measuring device may be impaired, for example, by a blockage of an opening through which the gas measuring device is in contact with an ambient medium, or by mechanical or electrical malfunctions.

[0004] To detect impaired functionality of a gas detector and to repair or replace the detector, methods are known in which a gas sensor of the detector is exposed to a test gas via a gas channel, and the corresponding sensor response is evaluated. Due to the use of a single gas channel, the influence of interfering variables on all sensor responses cannot be precisely determined, which may lead to erroneous measurements.

[0005] US patent 2008 / 0282765 A1 describes a gas sensor with a single gas channel, at least one gas sensor, a gas generator, and a pump. The pump directs test gas generated by the gas generator to the gas sensor for testing purposes.

[0006] US 5 667 558 A describes a gas scrubber with an outlet gas sensor and a pump for adding chemicals to a scrubbing suspension for scrubbing a gas.

[0007] US Patent 4,742,708 A describes an electrochemical gas detection system comprising an electrochemical sensor and a housing with a reservoir for an electrolyte. The gas detection system further includes a calibration system with a calibration gas source for calibrating the gas detection system.

[0008] DE 10 2009 052 957 A1 describes a device with a gas sensor in a sensor housing, which has a gas-permeable membrane for the gas sample to be analyzed and a measuring electrode, and a test gas generator, which has a generator housing that is attached in the area of ​​the gas-permeable membrane, has a gas inlet opening for the gas sample and has outlet openings for test gas directed towards the gas-permeable membrane.

[0009] GB 2 356 708 A describes a sensor system comprising: a housing containing at least one gas sensor, the housing having at least one opening to allow gas to reach the sensor; a test gas device for providing a test gas used to verify that the sensor is functioning; and a control device for analyzing the sensor's response to at least the test gas.

[0010] DE 20 2006 020 536 U1 describes a gas generator with an electrolysis cell having a housing which is sealed by a gas-permeable membrane for the escape of the test or calibration gas; a cathode made of a noble metal, a mixture of noble metals or of a carbon-containing material, which is in direct contact with an electrolyte; an anode made of a noble metal, a mixture of noble metals or of a carbon-containing material, which is in direct contact with an electrolyte, wherein the electrolyte contains an alkali metal salt, an alkaline earth metal salt, an ammonium salt of either acetic acid or a dicarboxylic acid; a control unit which also serves as a power source and which is connected to the electrodes.

[0011] DE 197 08 052 A1 describes a device for automatically calibrating gas sensors by supplying the sensor with a calibration gas, wherein the sensor is located in a measuring chamber which is provided with an opening for the escape of the calibration gas and a gas supply line, wherein a calibration gas container is arranged near the sensor which is provided with a thermovalve controlled by a processor, wherein the calibration gas container consists of a collection container which is provided with a microbore and on which an intermediate container with a multi-actuable electrically heated tin melt closure is arranged.

[0012] WO 2019 / 086 200 A1 describes a test device with a gas generator for generating test gas and with a control unit for controlling the gas generator and for determining a sensor response of the gas sensor.

[0013] It is an object of the present invention to provide an improved tester and an improved gas measuring device. In particular, it is an object of the present invention to provide a means of testing the current functionality of a gas measuring device.

[0014] The foregoing problem is solved by the features of the independent claims. Further features and details of the invention will become apparent from the dependent claims, the description, and the drawings. Features and details described in connection with the gas measuring device or the tester naturally also apply in connection with the test method according to the invention, and vice versa, so that the disclosure of the individual aspects of the invention always makes, or can make, reciprocal references.

[0015] A gas measuring device is thus presented.

[0016] The gas measuring device comprises at least one chemical gas sensor converting an analyte with a surrounding sensor chamber, at least one opening area forming a gas-permeable connection between the sensor chamber and an environment of the gas measuring device, and at least one tester according to the invention.

[0017] The tester comprises a test unit and an interface for reversibly connecting the test unit mechanically and / or communicatively to a gas sensor. The test unit includes a gas channel arrangement with a first gas channel and a second gas channel, and at least one gas generator configured to direct at least one test gas into the surrounding sensor chamber of the gas sensor via the gas channel arrangement during a first time interval of the test unit and during a second time interval of the test. The test unit is configured to direct the at least one test gas to the sensor chamber via the first gas channel during the first time interval and to direct the at least one test gas to the sensor chamber via the second gas channel during the second time interval.The first gas channel differs from the second gas channel in its channel structure, so that a test gas transport during the first time period has a different transport characteristic than during the second time period.

[0018] In the context of the presented invention, the term "test" refers to a procedure for validating or verifying a functionality. Accordingly, a test verifies whether a given function is correctly performed and / or provided.

[0019] In the context of the presented invention, a test gas is understood to be a gas with a known, predetermined composition and concentration of substances contained in the test gas.

[0020] The term "channel structure" refers to a structural characteristic of a gas channel, such as its shape, size, cross-sectional area, surface characteristics and / or length.

[0021] In the context of the presented invention, a gas generator is understood to be a device consisting of at least one generator electrode and a counter electrode, wherein, when several gas generators are used, a common counter electrode may be provided. The gas generator can also generate a test gas using a suitable tablet, such as a silver sulfide tablet.

[0022] The opening area according to the invention can, for example, be shielded against larger particles by a filter, but allow the passage of ambient medium, in particular ambient air. Typically, the gas sensor is located outside the test area above the test unit to detect a gas component in the ambient medium, in particular ambient air, entering through the opening area.

[0023] The sensor chamber is a space surrounding the gas sensor and accessible to the ambient medium containing the analyte to be analyzed via at least one opening. The sensor chamber is preferably spatially delimited by a sensor housing of the gas measuring device.

[0024] In the context of the presented invention, a reference value is understood to be a set of predetermined values ​​that can be mathematically related to a comparative value. A reference value can comprise a single value or a plurality of values, in particular a curve. A reference value can include positive and / or negative values ​​and, in particular, be specified as a band of a value range. A reference value can be a mathematical processing and / or condensation of one or more values.

[0025] In the context of the presented invention, a computing unit is understood to mean any programmable device. In particular, a computing unit can be a circuit, such as an ASIC, at least one processor, or a distributed system. Specifically, a computing unit is a computer.

[0026] The presented gas detector consists of at least one chemical gas sensor, which chemically reacts with the gas flowing towards the sensor to generate a sensor response, and at least one test unit. The gas sensor can be a pellistor, i.e., a heat flow sensor that burns a gas and measures the resulting heat flow, or an electrochemical sensor that reduces or oxidizes a gas and measures the electrical properties of the reduced or oxidized gas.

[0027] The test unit provided according to the invention preferably comprises a structure, such as a base, which may be made of a preferably gas-impermeable material, such as plastic. The base may in particular have a round, preferably a circular shape and be connected to the gas channel arrangement. The gas channel arrangement may, for example, be arranged in a cross shape within a circular base.

[0028] The test unit is specifically configured to test the functionality of the gas detector. To do this, the test unit can test a specific function of the gas detector, particularly the gas sensor, by pressurizing the gas sensor with a test gas using a gas generator.

[0029] For gassing the gas sensor, the test unit comprises the gas channel arrangement, with a specified number of gas channels, i.e., at least the first gas channel and the second gas channel, each with a distinct channel structure. The test gas is transported via these gas channels to the first and second time periods of the test unit's operation. The two time periods preferably have no overlap or an overlap that is negligible from a metrological perspective. Alternatively, the test unit can be designed to allow the two time periods to overlap for the test according to the invention.

[0030] According to the invention, in addition to the first time period and the second time period, it is also possible to provide at least one further time period for a test by the test unit in an embodiment of the gas measuring device according to the invention.

[0031] Due to the differing transport characteristics of the respective gas channels, the concentration-time profile of a gas to be detected changes at the detection point in the gas sensor, and thus the sensor response of the gas sensor changes when purged with test gas during the two different time periods. This results in different gas clouds with different concentration-time profiles being generated when the gas sensor is purged with test gas during the respective time periods. These differences can also be influenced differently by environmental parameters such as wind. In particular, the functionality of the gas sensor can be tested by purging it with test gas during the first time period, and the functionality of the gas detector's opening can be tested by purging it with test gas during the second time period.

[0032] Furthermore, sensor values ​​obtained from the gas sensor during the first time period when the gas sensor was exposed to test gas, and sensor values ​​obtained during the second time period when the gas sensor was exposed to test gas, can be mathematically related to each other in order to draw conclusions about properties of the gas measuring device or an environment of the gas measuring device.

[0033] In particular, the two transport characteristics can differ during the two time periods due to different interactions or different influences of the environment on the gas flowing through the gas channel arrangement. Preferably, the first gas channel and at least one second gas channel of the gas channel arrangement are designed differently for this purpose.

[0034] The gas channel arrangement can, in principle, include at least one additional gas channel besides the first and second gas channels.

[0035] It may be provided that the first and second gas channels differ in that a first gas channel opening of the first gas channel is closer to the gas sensor than a second gas channel opening of the second gas channel.

[0036] Alternatively or additionally, it may be provided that the second gas duct opening is located closer to the at least one opening area than the first gas duct opening.

[0037] By using different channel structures in the respective gas channels of the presented gas measuring device, test gases with different flow properties and thus different transport characteristics can be generated for gassing the gas sensor. For example, a first gas channel with a gas channel geometry that ends close to the gas sensor can be used to test the gas sensor itself, while a gas channel with a gas channel geometry that ends further away from the gas sensor relative to the first gas channel can be used to test the flow behavior of the opening area and / or a sensor input of the gas measuring device.

[0038] With a small distance between the end of a gas channel and a gas sensor, environmental influences, such as side currents caused by ambient wind, have a minimal impact on the corresponding sensor readings. Accordingly, this type of gas channel geometry is particularly well-suited for testing the functionality and sensitivity of the gas sensor, as low interference variance and / or a minimal influence of interfering variables can be expected during such testing.

[0039] Since a large distance between the end of a gas channel and a gas sensor means that environmental influences, such as side currents caused by ambient wind, have a strong impact on the corresponding sensor readings, and since preferably an opening area and / or a sensor inlet of the gas measuring device is located closer to the end of the gas channel than the gas sensor, such a gas channel geometry is particularly advantageous for testing an opening area and / or a sensor inlet of the gas measuring device. In particular, such a gas channel geometry is especially advantageous for testing an opening area and / or a sensor inlet of the gas measuring device because the degree of blockage of an opening strongly influences the transport characteristics of the corresponding test gas between the end of the gas channel and the gas sensor.

[0040] It may also be provided that the first gas channel and at least one further gas channel differ from each other in their channel structure by a roughness of their inner surface.

[0041] By varying the roughness of the internal surfaces of the respective gas channels in the presented gas measuring device, test gases with different transport characteristics, particularly different flow properties, can be generated for gassing the gas sensor. For example, a first gas channel with a low, i.e., particularly smooth, internal surface can be used to test the gas sensor itself, while a gas channel with a relatively higher roughness internal surface compared to the first gas channel can be used to test the flow behavior of the opening area of ​​the gas measuring device.

[0042] Because a test gas flows very quickly through a gas channel with a low roughness of its inner surface, environmental influences, such as side currents caused by ambient wind, have less of an impact on the compact gas cloud at the gas channel's outlet than would be the case with a slowed, diffuse gas release at the outlet of a rough channel. Accordingly, such a gas channel is particularly well-suited for testing the functionality and sensitivity of the gas sensor, as low interference variance and thus a minimal influence of interfering variables can be expected during such a test.

[0043] Because a test gas flowing through a gas channel with a high degree of roughness on its inner surface slows down due to adsorption and desorption processes on the channel walls, a delayed gas cloud forms at the outlet. This gas cloud is more elongated and has a lower concentration at the detection point, making it more susceptible to environmental influences such as wind. Therefore, such a gas channel is particularly well-suited for testing the opening of a gas detector, as its degree of blockage is mathematically linked and thus correlated with the influence of side flows caused by ambient wind.

[0044] It may further be provided that at least one gas channel includes a temperature control unit configured to change the temperature inside the gas channel such that the test gas differs in temperature from the test gas during the first time period. The test gas for the first time period may be a different test gas than the test gas for the second time period.

[0045] By varying the temperature of the test gas in the presented gas measuring device, test gases with different transport characteristics can be generated for gassing the gas sensor. For example, a first gas channel, equipped with a temperature control unit for heating the gas channel, can be used to test the gas sensor, while another gas channel in the gas channel arrangement, either without a temperature control unit or with a temperature control unit for cooling the gas channel, can be used to test the flow behavior of the gas measuring device's opening.

[0046] Since a test gas flows rapidly through a gas channel at a high temperature, it exits the channel as a compact gas cloud. Ambient atmospheric influences, such as wind, have less impact on this compact gas cloud at the gas channel's outlet than they would at a lower temperature. Therefore, a heated and / or heatable gas channel is particularly well-suited for testing the gas sensor, as a low level of interference variance—that is, a minimal influence from interfering variables—can be expected during such a test.

[0047] Since a test gas flows slowly through a gas channel at a low temperature, a delayed gas cloud forms at the outlet. This gas cloud is stretched over time and appears at a lower concentration at the detection point, making it more susceptible to environmental influences such as wind. Therefore, a cooled and / or coolable gas channel is particularly advantageous for testing the opening of a gas detector relative to the ambient atmosphere, as the degree of blockage is mathematically linked and thus correlated with the influence of side currents caused by ambient wind.

[0048] It may also be provided that the first gas channel and the at least one further gas channel are in fluid communication with each other, in particular via respective chambers of the gas channels, and that the first gas channel is not in direct fluid contact with an environment of the test unit and that the at least one further gas channel is in direct fluid contact with the environment of the test unit.

[0049] To minimize the influence of environmental factors on a test gas for testing a gas sensor, a gas channel with a chamber that is not in direct fluid contact with the environment is particularly advantageous.

[0050] To maximize the influence of environmental factors on a test gas for testing a gas sensor, a gas channel with a chamber that is in direct fluid contact with an environment is particularly advantageous.

[0051] In a preferred embodiment, the at least one gas generator is configured to direct a different test gas through the corresponding gas channel during the first time interval than during the second time interval. The two different test gases particularly preferably have two different diffusion coefficients. This enables different transport characteristics, in particular different concentration-time profiles, independent of the structure of the gas channel arrangement.

[0052] In In one embodiment, a time interval exists between the first and second time periods during which no test gas is supplied by the gas generator. This time interval is at least 1 minute, particularly at least 30 minutes, and most preferably at least 2 hours. In this embodiment, there is a clear temporal separation between a first phase of the test during the first time period and a second phase of the test during the second time period. This allows chemical processes occurring during the first time period to be observed with particular reliability before a further test phase of the gas measuring device takes place during the second time period.

[0053] The test unit of the presented gas detector can comprise at least one processing unit. The at least one processing unit is preferably configured to receive a signal from the gas sensor and to determine a measured value from it. The processing unit is further configured to determine and output test information during the first time interval and / or during the second time interval. This test information indicates whether the gas detector is faulty. The determination of the test information is based on a comparison between the measured value and a predetermined gas sensor threshold value or between a specific measured value trend parameter and a predetermined trend parameter. For example, the test information can indicate whether the at least one opening area is blocked and / or whether the gas sensor is functioning. In The following embodiments provide various examples of the possible operation of such a computing unit. The use of a comparison between predetermined measured values ​​or a predetermined measurement profile enables a particularly simple and reliable determination of the test information by the computing unit.

[0054] In an example of the preceding embodiment, the processing unit is configured to perform a comparison between the measured value and a predetermined gas sensor threshold value for one of the two time periods, and to perform a comparison between the measured value trend parameter and the predetermined trend parameter for the other of the two time periods. This results in different determination procedures being executed during the respective time periods, ultimately leading to the test information.

[0055] Alternatively or additionally, the processing unit can perform an evaluation based on a multiple of past measurements from the first and / or second time periods. Such consideration of the measurement history can lead to a particularly reliable evaluation.

[0056] The processing unit can alternatively or additionally include at least one control module for controlling components of the gas detector, such as the gas generator. Alternatively or additionally, the processing unit can include an analysis module for evaluating the respective measured values ​​from the gas sensor of the gas detector. In particular, the processing unit serves to operate the gas detector. For this purpose, the processing unit can be communicatively connected to the gas sensor and / or the respective gas generators to exchange control commands. The processing unit can include one or more processors configured to operate the gas detector.The at least one computing unit can be located in a computer, such as a server, particularly in the cloud, and communicate with the gas measuring device via a communication interface. Alternatively, the at least one computing unit can be located, at least partially, within the gas measuring device itself.

[0057] It can further be provided that the computing unit provided according to the invention is configured to mark the gas sensor or gas measuring device as faulty if a difference or quotient of measured values ​​to be determined by the gas sensor during the first time period or intermediate results calculable therefrom and at least one predetermined reference value is greater than a predetermined gas sensor threshold value, and if a difference or quotient of a variable describing the signal size, such as the decay time, the peak height, the integral or intermediate results calculable therefrom, of measured values ​​determined by the gas sensor during the second time period to a predetermined reference value is greater than a predetermined blockage threshold value, to mark the opening area through which the gas channel is in direct communication with the environment as blocked.

[0058] The functionality of the gas sensor can be tested by means of a mathematical comparison of measured values ​​obtained during gassing with test gas through the gas channel provided according to the invention and / or a value obtained by their mathematical processing and a predetermined reference value.

[0059] Since the gas sensor provided according to the invention is a chemical gas sensor, it chemically converts the test gas when functioning correctly, i.e., without errors, so that the concentration of the test gas decreases over time and the measured values ​​determined by the gas sensor change accordingly.

[0060] Should the comparison between the respective measured values ​​of the gas sensor obtained during the first time period during gassing and a reference value reveal no or only a slight change in the measured values, for example, if the difference or quotient between the measured values ​​and / or a value obtained through their mathematical processing and the reference value exceeds a predetermined gas sensor threshold, a malfunction of the gas sensor or gas measuring device can be inferred. Accordingly, the processing unit provided according to the invention is configured to mark the gas sensor or gas measuring device as faulty in such a case and, for example, to store an error message in a memory of the gas sensor, the gas measuring device, and / or in an error memory and / or in a memory of the processing unit.The reference value can, for example, be a sensor value corresponding to the half-life of a degradation curve of a reference sensor, or it can refer to the development of the characteristic value of the respective sensor itself.

[0061] The functionality of the gas detector's opening can be tested by mathematically comparing a parameter determined during the second time period of gassing with test gas—such as a decay time, peak height, integral, or other parameters—with a predefined reference value. Since bypass air, such as ambient air, flows into the gas detector and / or test gas flows out of the gas detector through the opening, an unblocked opening minimizes the concentration of the test gas over time. This causes the test gas concentration to decrease, resulting in rapid changes in the measured values ​​from the gas sensor. Therefore, a parameter describing the height and extent of the signal is particularly suitable for testing the opening's functionality.One such parameter would be, for example, the peak height in combination with the decay time or the amount of gas converted at the sensor, which can be represented via the integral.

[0062] To verify the proper sensitivity of a gas sensor, the gas sensor can be exposed to test gas using the gas generator according to the invention. The exposure is initially carried out by using, for example, a first gas channel that is as independent as possible from the respective ambient conditions and / or is not in direct contact with the environment.

[0063] To assess whether unimpeded gas access to a gas sensor under test is possible and / or to detect any blockages or obstructions, test gas is directed to the gas sensor, for example, through a second gas channel using the gas generator according to the invention. This second gas channel promotes a particularly strong interaction of the test gas with the ambient atmosphere and is preferably in direct contact with, or only separated from, the environment by a filter.

[0064] As a result of the gas supply through the gas generator provided according to the invention, the gas sensor reacts with a sensor signal proportional to the concentration of the supplied test gas, both when gassing occurs through the first gas channel and when gassing occurs through the second gas channel. The resulting time-dependent profile of measured values ​​determined by the gas sensor is evaluated by an analysis unit for gassing through the first gas channel and for gassing through the second gas channel.

[0065] Firstly, when evaluating the measured values ​​from the gas channel, it is possible to compare a general curve shape of a concentration-time profile from the gas sensor with a predefined reference value, for example, one stored in the analysis unit's memory, in the form of a fit function. Such a comparison allows for a qualitative evaluation of the curve shape of the measured values ​​obtained from the gas sensor. This type of comparison with a fit function maps the kinetics of a measurement signal from the gas sensor against time, based on a normalized curve or a curve expressed, for example, in concentration units. Suitable fit parameters of a mathematical function can be used for this purpose.

[0066] For the quantitative evaluation of the measured values ​​of the gas channel, mathematical parameters of the measured values ​​such as maximum, minimum, half-width, half-life of a falling branch of the measured values, a signal amplitude of the measured values ​​e.g. in concentration units at certain times on the falling branch, surface integrals with different limits, standard deviations over different value ranges, medians and any other technically suitable mathematical parameter can be used.

[0067] In particular, the comparison performed by the computing unit to determine the test information preferably depends on a determination of a decay time, a mathematical derivative, a statistical mean, a maximum value and / or an integral based on the determined measurement curve, as well as a consideration of previous measurement values.

[0068] Furthermore, it is possible to derive characteristic quantities from partial sections of the gas sensor's measured values ​​by extrapolating, thus adequately describing the sensor's behavior. For example, a linear extrapolation of measured values ​​in concentration units against time over a selected range of values ​​between two time points before reaching a maximum value can provide information about the sensor's response behavior, response times, and dead times. Similarly, after reaching the maximum value, information about the sensor's decay behavior and the unobstructed nature of a gas inlet to the sensor can be determined. Other suitable plots of the gas sensor's measured values ​​can be used to evaluate the gas sensor's functionality.For example, the measured values ​​of the gas sensor can be plotted against a gas dose, i.e. an integral over a time course of the measured values, and evaluated to determine the test information.

[0069] In particular, actual values, i.e., measured values ​​from the gas sensor, and reference values ​​can be compared using suitable mathematical methods. The reference values ​​can, for example, be defined as tolerance bands that describe ranges for properly functioning gas sensors and gas generators. If the measured values ​​of the gas sensor deviate from or exceed these tolerance bands, various conditions or malfunctions of the gas sensor can be inferred. For example, the gas sensor may react too insensitively, too sensitively, too slowly, or too quickly to the test gas; the test gas may be transported and / or processed too quickly or too slowly. In particular, the curve of the measured values ​​may be shifted in time or in its concentration values ​​compared to a predefined reference curve.Any deviation from a predefined reference value is evaluated according to an evaluation logic stored in an evaluation unit and, if necessary, output to an end user after a successful repeat test. In particular, an action recommendation can be issued to a user based on an evaluation of the gas sensor's measured values, especially as part of the test information.

[0070] Should the comparison between the determined decay time and the reference value reveal a slow change in the measured values, for example, if the difference between the decay time and the reference value exceeds a predefined gas sensor threshold, a malfunction of the opening and / or a blockage can be inferred, and the gas measuring device can be marked as faulty accordingly. The processing unit provided according to the invention is configured to mark the opening, in particular the opening area, or the gas measuring device as faulty in such a case and, for example, to store an error message in a memory of the gas measuring device and / or in an error memory and / or in a memory of the processing unit.The reference value can, for example, be a determined sensor value at a decay time, in particular a half-life of a degradation curve of a reference sensor in a reference chamber with a completely continuous opening.

[0071] It may also be provided that the processing unit is configured to mark the gas measuring device as faulty via a corresponding test message if, after a gas supply of the gas sensor with test gas through a gas channel whose inner surface has a roughness lower than that of the inner surface of another gas channel, the measured values ​​are greater or less than a predetermined reference value after a predetermined time, and if, after a predetermined time, the measured values ​​of the gas sensor with test gas through the other gas channel are greater or less than a predetermined reference value, the opening through which the other gas channel is in direct fluid contact with the environment of the gas measuring device is marked as blocked via the corresponding test message.

[0072] Since a faulty gas sensor disrupts the conversion of a test gas, resulting in only minimal changes in the test gas concentration, measurements taken at a time when the conversion of the test gas at a reference sensor affects its concentration can indicate the functionality of the gas sensor and thus provide the corresponding test information. The gas sensor's measurements at this point in time can be evaluated so that if these measurements are higher than a predefined reference value, or if the measured values ​​differ from a maximum test gas concentration by only an amount that is below or, depending on the sign of the corresponding measurement signal, above a predefined threshold, it can be assumed that the gas sensor, and consequently the gas measuring device, is faulty.

[0073] Since interfering variables must be minimized when testing the gas sensor, gassing through a gas channel suitable for particularly fast gas transport, especially through a gas channel with a particularly smooth inner surface, is particularly advantageous for testing the gas sensor.

[0074] Since testing the opening of a gas detector involves examining the interaction between a test gas and its environment, purging the gas sensor through a gas channel is suitable. This channel allows the test gas to interact with the environment for an extended period. A gas channel with a particularly rough inner surface is especially appropriate for this purpose. Such a rough surface slows down the test gas, causing it to flow slowly and thus allowing for a longer interaction with the surrounding medium before reaching the gas sensor.

[0075] It may also be provided that the processing unit is configured to mark the gas sensor and / or the gas measuring device as faulty via the test information if measured values ​​obtained during the gas sensor's purging with test gas through a gas channel whose internal temperature is higher than the internal temperature of another gas channel are greater or, depending on the sign of a corresponding measurement signal, less than a predetermined reference value after a predetermined time, and if measured values ​​obtained during the gas sensor's purging with test gas through the other gas channel are greater or less than a predetermined reference value after a predetermined time, an opening through which the other gas channel is in direct fluid contact with the gas measuring device's environment is marked as blocked via the test information.

[0076] Since interfering variables must be minimized when testing the gas sensor, gassing through a gas channel suitable for particularly fast gas transport, especially through a particularly warm gas channel, is particularly advantageous for testing the gas sensor.

[0077] Since testing the opening of a gas measuring device involves an interaction between a test gas and an environment, gassing the gas sensor through a gas channel suitable for particularly slow gas transport, especially through a particularly cold gas channel, is particularly advantageous for testing the opening.

[0078] It may also be provided that the computing unit is configured to recalibrate the gas sensor based on the difference between measured values ​​to be determined by the gas sensor during at least one first state and at least one predefined reference value, or between such values ​​and a predefined gas sensor threshold value.

[0079] To repair a gas sensor marked as faulty or to continuously adapt the gas sensor to a current situation, the gas sensor can be recalibrated. For this purpose, a comparison table or an assignment logic can be provided, for example, to assign the respective measured values ​​determined by the gas sensor to the respective values ​​to be output on an output scale, depending on a deviation between the measured values ​​determined by the gas sensor during the first state and a predefined reference value. For example, a warning threshold, above which a warning tone is to be emitted, can be raised or lowered depending on the deviation. In this sense, a warning tone is also test information. Generally, test information is information that indicates a result of the test during at least one of the two time periods according to the invention.

[0080] In particular, it may be possible to use a trend of measured values ​​obtained by the gas sensor to recalibrate the gas sensor. For this purpose, for example, an average value or any other technically suitable characteristic value can be calculated from a large number of measured values ​​obtained at different times.

[0081] It may further be provided that the first gas channel is designed such that the test gas flows through the first gas channel faster than through the second gas channel, and that the computing unit is configured to determine a difference of an initial time between the start of gassing with test gas through the first gas channel and a time of increase in measured values ​​of the gas sensor, as well as a further time between the start of gassing with test gas through the at least one further gas channel and a time of increase in measured values ​​of the gas sensor, and to deduce a diffusion time of the test gas to the measuring device from the difference and to take this diffusion time into account when carrying out a test.

[0082] By determining such a diffusion time, which can preferably change depending on an ambient temperature, quantities to be calculated by the processing unit of the gas measuring device, such as a decay time or any other quantity to be calculated or determined, such as a temperature, can be corrected.

[0083] It may also be provided that the computing unit is configured to infer a wind speed outside the opening range by comparing measurements taken by the gas sensor during the first time period with measurements taken by the gas sensor during the second time period.

[0084] By comparing gas sensor readings obtained during gassing with test gas (generated through a fast-conducting gas channel) with readings obtained during gassing with test gas through a slow-conducting gas channel, conclusions can be drawn about the properties of an interfering variable interacting with the test gas, particularly the velocity of a bypass flow entering through the opening. Similarly, this comparison allows conclusions to be drawn about the wind speed outside the gas measuring device, i.e., outside the opening area. The greater the deviations from reference values, the higher the wind speed.

[0085] It may further be provided that the test unit comprises a first gas generator and at least one further gas generator, and that the computing unit is configured to, in the event that the gas sensor is to be marked as faulty when propelled by the first gas generator, to propelle the gas sensor with test gas by the at least one further gas generator, and in the event that the gas sensor is not to be marked as faulty when propelled with test gas by the further gas generator, to mark the gas sensor as faultless and the first gas generator as faulty and to provide the corresponding test information.

[0086] Using multiple gas generators, for example, a validation gas generator, preferably used only when a gas sensor needs to be marked as faulty, can be used to verify the gas generator underlying a test that resulted in the gas sensor or orifice being marked as faulty. Accordingly, the validation gas generator can prevent a false fault marking of a gas sensor or gas measuring device.

[0087] It may also be provided that the first gas channel and the second gas channel are arranged parallel to each other or are connected to form at least one labyrinth.

[0088] A labyrinth of gas channels minimizes the influence of environmental factors on the measured values ​​obtained using the gas sensor.

[0089] The tester according to the invention is preferably reversibly connectable to a gas measuring device and / or a gas sensor, so that the tester can be used to test a large number of gas measuring devices. Accordingly, reference is made to the advantages described in connection with the presented gas measuring device with regard to the tester.

[0090] In another aspect, the presented invention relates to a test method for testing a gas measuring device. The test method comprises the following steps: a) Providing a gas measuring device according to one of the preceding embodiments; b) Controlling the at least one gas generator such that it directs at least one test gas into the surrounding sensor chamber of the gas sensor via the gas channel arrangement for a first time period of a test and for a second time period of the test; c) Determining measured values ​​determined by the gas sensor during the first time period and / or during the second time period;d) Determining and outputting test information during the first time period and / or during the second time period, wherein the test information indicates whether the gas detector is faulty, and wherein the determination of the test information is based on a comparison between the measured value or a characteristic value calculated therefrom and a predetermined gas sensor threshold value, or between a specific measured value trend parameter calculated according to a predetermined procedure and a predetermined trend parameter.

[0091] The presented test procedure is particularly intended for the operation of the presented gas measuring device and the presented tester, so that with regard to the advantages of the presented procedure, reference is made to the described advantages of the gas measuring device and / or the tester.

[0092] Further measures improving the invention will become apparent from the following description of some exemplary embodiments of the invention, which are illustrated in the figures. All features and / or advantages arising from the claims, the description, or the drawings, including design details and spatial arrangements, can be essential to the invention, both individually and in various combinations. The figures schematically show: Figure 1 shows a cutaway side view of a possible embodiment of the gas measuring device according to the invention, Figure 2 shows a comparison of measurement data obtained using the gas measuring device. Figur 1 Figure 3 shows a comparison of measurement data obtained during gassing through a first gas channel and measurement data obtained during gassing through a second gas channel. Figur 1 Figure 4 shows another possible embodiment of the presented gas measuring device, and Figure 5 shows a sequence of a possible embodiment of the method according to the invention.

[0093] In Fig. 1 A gas detector 100 is shown in a cutaway side view. The gas detector comprises a test unit 101 and a gas sensor 103.

[0094] The test unit 101 comprises a gas generator 105, in particular a chemical one, for converting an analyte of a test gas for testing the gas measuring device 100.

[0095] The gas generator 105 consists of a generator electrode in a first generator chamber 107 and a counter electrode. Furthermore, a further generator chamber 109 is provided. In particular, it can be provided that the counter electrode is used jointly by several gas generators.

[0096] The first generator chamber 107 is in contact with a first gas channel 111 via a first gas outlet opening 129, so that test gas produced by the gas generator 105 flows through the first gas outlet opening 129 into the first gas channel 111. To prevent any electrolyte stored in the first generator chamber 107 from escaping into the first gas channel 111, the first gas outlet opening 129 includes a gas-permeable membrane that is permeable to the test gas and impermeable to the electrolyte.

[0097] The further generator chamber 109 is in contact with a second gas channel 113 via a further gas outlet opening 131, so that test gas generated by the optional further gas generator and / or an optional further generator electrode flows through the further gas outlet opening 131 into the second gas channel 113. To prevent any electrolyte stored in the further generator chamber 109 from escaping into the second gas channel 113, the further gas outlet opening 131 includes a selectively gas-permeable membrane that is permeable to the test gas and impermeable to the electrolyte.

[0098] The test unit 101 is permanently connected to the gas sensor 103. Additionally, the test unit 101 is designed to have an interface for communicative and / or mechanical connection to the gas sensor 103.

[0099] The test unit 101 can be designed as a circular base on which the first gas channel 111 and the second gas channel 113 are arranged or into which the first gas channel 111 and the second gas channel 113 are integrated.

[0100] The first gas channel 111 includes a first chamber 115.

[0101] The second gas channel 113 comprises a further chamber 117 with an opening 119 through which the chamber 117 is in contact with its environment via a filter, allowing ambient medium, such as air, to flow into the chamber 117 and test gas to flow out of the chamber 117. The first chamber 115 and the further chamber 117 are fluidically connected, allowing gases to flow from the further chamber 117 into the first chamber 115. The flow between the first chamber 115 and the further chamber 117 is guided and / or limited by flow guides 123. In the illustrated embodiment, the first chamber 115 and the further chamber 117 form a sensor chamber surrounding the gas sensor 103.

[0102] The first gas channel 111 has a channel structure that differs from the channel structure of the second gas channel 113. In this case, the first gas channel 111 is longer than the second gas channel 113, such that the distance between one end of the first gas channel 111 and an inlet region 121 of the gas sensor 103 is shorter than the distance between one end of the second gas channel 113 and the inlet region 121 of the gas sensor 103.

[0103] Furthermore, the test unit 101 includes a first computing unit 125, which is configured as a control module to control the gas generator 105 and the gas sensor 103. For this purpose, the first computing unit 125 can communicate with the gas generator 105 and the gas sensor 103 via a communication interface, such as a cable or a wireless connection. The first computing unit 125 can comprise one or more processors configured to control the gas generator 105 and the gas sensor 103 individually or jointly.

[0104] To test the gas measuring device 100, the first processing unit 125 controls the gas generator 105 such that, in a first state during the first time interval of a test of the test unit 101, the gas generator 105 supplies the gas sensor 103 with test gas via the first gas channel 111. In a further state during a second time interval of the test, the first processing unit 125 controls the gas generator 105 such that it supplies the gas sensor 103 with test gas via the second gas channel 113.

[0105] Since the first gas channel 111 and the second gas channel 113 differ in their channel structure, the test gas flows through the first gas channel 111 and the second gas channel 113 with different transport characteristics.

[0106] In this case, during the first time interval, the test gas exits at the end of the first gas channel 111 at a short distance from the inlet area 121 of the gas sensor 103. Accordingly, the test gas flows rapidly and directly to the gas sensor 103, minimizing the influence of interfering variables, such as inflows of ambient medium from the surroundings or outflows of test gas into the surroundings. Therefore, a measurement of the test gas by the gas sensor 103 in the first state during the first time interval is subject to a reduced influence of interfering variables compared to the second time interval. Consequently, measured values ​​obtained by the gas sensor 103 during the first state are particularly valid with regard to the functionality of the gas sensor 103.

[0107] In the subsequent state during the second time period, the test gas exits at the end of the second gas channel 113 at a large distance from the sensor inlet 121 and in close proximity to the opening area 119.

[0108] Due to the long diffusion paths and the associated long diffusion time, the measured values ​​obtained by gas sensor 103 during this second time period are particularly susceptible to interference from the inflow of an ambient medium and / or the outflow of test gas. In particular, the outflow of the test gas represents an important transport pathway for the generated test gas, as the outlet opening of 113 is located in the immediate vicinity of the opening area 119 with the gas inlet opening. Accordingly, the measured values ​​obtained during the second time period are particularly affected by and valid for detecting a blockage of the opening area 119.

[0109] Accordingly, it is planned that the functionality of the gas sensor 103 will be tested based on measured values ​​obtained during the first time period, and the functionality or permeability of the opening area 119 for gases will be tested based on measured values ​​obtained during the second time period.

[0110] For analyzing measurements obtained by the gas sensor 103, a second processing unit 127 can optionally be provided in addition to the first processing unit 125. This second unit is designed as an analysis module and communicates with the gas sensor 103 via a communication interface, such as a cable or a wireless interface. Of course, the first processing unit 125 can also be used to analyze measurements obtained by the gas sensor 103.

[0111] In an embodiment not shown, a different test gas is passed through the corresponding gas channel (e.g., the first gas channel) during the first time interval than during the second time interval. The two different test gases preferably differ in their diffusion coefficients, so that the transport characteristics are already different during the first time interval than during the second time interval simply due to the different test gases.

[0112] In another embodiment, only a single gas channel is provided to supply the two time periods with different transport characteristics of the test gas. These different transport characteristics are based on different test gas properties, such as different test gases used and / or different test gas temperatures.

[0113] In Fig. 2 Diagram 200 is shown, which spans on its ordinate 201 over a sensor signal in [ppm] and on its abscissa 203 over time in [hh:mm:ss].

[0114] A curve 205 represents measured values ​​that were determined by the gas sensor 103 during a gassing with test gas in the first state during the first time period from the first gas channel 111 and during which the opening area 119 for gases was blocked, i.e. gas-impermeable.

[0115] A curve 207 represents measured values ​​that were determined by the gas sensor 103 during a gassing with test gas in the first state during the first time period from the first gas channel 111 and during which the opening area 119 was permeable to gases, i.e. not blocked.

[0116] Furthermore, in Fig. 2 a diagram 220 is shown, which spans on its ordinate 221 over a sensor signal in [ppm] and on its abscissa 223 over time in [hh:mm:ss].

[0117] A curve 225 represents measured values ​​that were determined by the gas sensor 203 during a gassing with test gas in the further state during the second time period from the second gas channel 113 and during which the opening area 119 for gases was blocked, i.e. gas-impermeable.

[0118] A curve 227 represents measured values ​​that were determined by the gas sensor 103 during a gassing with test gas in the further state during the second time period from the second gas channel 113 and during which the opening area 119 was permeable to gases, i.e. not blocked.

[0119] Comparing curves 205 and 207 with curves 225 and 227, it becomes clear that the blockage of opening area 119 during gassing with test gas through the second gas channel 113, as shown in curve 227, differs significantly from that in curve 225. Furthermore, the blockage of opening area 119 during gassing with test gas through the first gas channel 111, as shown in curve 205, differs only very slightly from that in curve 207. Accordingly, based on measurements taken by the gas sensor 103 during the subsequent phase, a clear distinction can be made between a state in which opening area 119 is blocked and a state in which the opening is permeable to gases.

[0120] To detect a blockage, measured values ​​obtained by the gas sensor 103 during the second time period can be used to determine, i.e., calculate or estimate, a decay time, such as a half-life or other value, at a predetermined time after the start of gassing. If the difference between the decay time and a predetermined reference value is greater than a predetermined blockage threshold, it can be assumed that the opening area 119, and in particular a filter within the opening area 119, is blocked. Accordingly, in this case, the processing unit 125 is designed to mark the gas measuring device 100 as blocked and, for example, store a corresponding error message in an error memory.

[0121] In particular, a decay time can be calculated, for example, by the area under a maximum between a given start time and a given stop time.

[0122] In Fig. 3 Diagram 300 is shown, which displays a dimensionless relative sensor signal on its ordinate 301. This signal changes due to the influence of the wind for different wind speeds, which are plotted on the abscissa 303 in [m / s].

[0123] A curve 305 is based on measured values ​​obtained by the gas sensor 103 during a gassing with test gas through the second gas channel 113.

[0124] A curve 307 is based on measured values ​​obtained by the gas sensor 103 during a gassing with test gas through the first gas channel 111.

[0125] It is clearly evident that the distance between curve 305 and curve 307 increases with increasing wind speed. This means that the wind speed can be inferred from the distance between curves 305 and 307, and that the arrangement used in curve 307 is significantly less affected by wind and therefore more suitable for checking the sensitivity of sensor 301. This relationship can be used, for example, to deactivate a warning function of the gas detector 100 when wind speeds exceeding a predefined threshold are detected.

[0126] In Fig. 4 A gas measuring device 400 is shown.

[0127] The gas measuring device 400 comprises a first gas channel 401, which is designed here as a chamber and in which a first gas generator 403 and a computing unit 419 are arranged.

[0128] The gas measuring device 400 also includes a second gas channel 405, which is designed here as a chamber and in which another gas generator 407 is arranged.

[0129] The first gas channel 401 is in fluid contact with the second gas channel 405 via gas transfers 409, so that a gas exchange between the first gas channel 401 and the second gas channel 405 is possible.

[0130] The second gas channel 405 is in fluid contact with an environment via an opening 411, which serves as a sensor input and in this sense forms the opening area for the gas measuring device 400, so that a direct, immediate gas exchange between the environment and the second gas channel 405 is possible.

[0131] The first gas channel 401 is in contact with a sensor membrane 413, which separates an electrolyte of a gas sensor 417 of the gas measuring device from the first gas channel 401.

[0132] Since the first gas channel 401 is not in direct contact with a fluid environment, a test gas supplied by the first gas generator 403 is only minimally affected by environmental conditions of the gas measuring device 400, such as wind. Accordingly, the first gas channel 401 is particularly well suited for testing the gas sensor 417.

[0133] In order to prevent a false negative error message that incorrectly marks the gas sensor 417 as faulty in the event that the measured values ​​of the gas sensor 417 during a gassing of a sensor interior 415 with test gas by the first gas generator 403 indicate that the gas sensor 417 is to be marked as faulty, the first gas generator 403 can be tested using the further gas generator 407.

[0134] To test the first gas generator 403, the gas sensor 417 is exposed to test gas supplied by the second gas generator 407. If the gas sensor 417 is not marked as faulty when exposed to test gas from the second gas generator 407, the gas sensor 417 is marked as fault-free and the first gas generator 403 as faulty. For this purpose, a processing unit of the gas measuring device 400 can modify or generate a corresponding error message in an error memory of the gas measuring device 400 or in a memory of the processing unit.

[0135] In Fig. 5 Figure 500 illustrates the sequence of steps in the presented procedure.

[0136] Procedure 500 begins with a provisioning step 501 to provide a possible configuration of the presented gas measuring device. For example, a possible configuration of the presented tester can be combined with a gas sensor to form a possible configuration of the presented gas measuring device.

[0137] In a control step 503, at least one gas generator of the gas measuring device is controlled in such a way that, during a first time period of a test and during a second time period of the test, it gasses the surrounding sensor space of the gas sensor with the at least one test gas via the gas channel arrangement.

[0138] In a determination step 505, which at least temporarily runs parallel to the control step 503, the measured values ​​determined by the gas sensor during the first time period and / or during the second time period are determined. This can advantageously be done by having a processing unit of the gas measuring device read out the respective measured values ​​determined by the gas sensor and store them in a working memory.

[0139] In a marking step 507, the gas measuring device is marked as faulty via test information if the evaluation algorithms detect a deviation from the target state. According to the invention, the marking is carried out by determining and outputting test information during the first time interval and / or during the second time interval, wherein the test information indicates whether the gas measuring device is faulty, and wherein the determination of the test information is based on a comparison between the measured value and a predetermined gas sensor threshold value or between a specific measured value trend parameter and a predetermined trend parameter. REFERENCE MARK LIST

[0140] 100, 400 Gas measuring device 101 Test unit 103, 417 Gas sensor 105 Gas generator 107 Base 109 Gas channel arrangement 111, 401 First gas channel 113, 405 Second gas channel 115 First chamber 117 Second chamber 119 Opening area 121 Inlet area 123 Flow guide device 125 First computing unit 127 Second computing unit 129 First gas outlet opening 131 Second gas outlet opening 200, 220, 300 Diagram 201, 221, 301 Ordinate 203, 223, 303 Abscissa 205, 207, 225 227, 305, 307 Trajectory 403 First gas generator 407 Second gas generator 409 Gas passages 411 Opening 413 Sensor membrane 415 Sensor interior 419 Computing unit 500 Method 501, 503, 504, 507 Method step

Claims

1. Tester for a gas measuring device (100), comprising: - a test unit (101), and - an interface for reversibly connecting the test unit (101) mechanically and / or communicatively to a gas sensor (103), wherein the test unit (101) comprises: - a gas channel arrangement (109) comprising a first gas channel (111) and a second gas channel (113), and - at least one gas generator (105) that is configured to conduct at least one test gas into a surrounding sensor chamber of the gas sensor (103) via the gas channel arrangement (109) in a first time period of a test of the test unit (101) and in a second time period of the test, wherein the test unit (101) is configured to conduct the at least one test gas to the sensor chamber via the first gas channel (111) in the first time period and to conduct the at least one test gas to the sensor chamber via the second gas channel (113) in the second time period, and wherein the first gas channel (111) differs from the second gas channel (113) in its channel structure so that a test gas transport process during the first time period has a different transport characteristic than during the second time period.

2. Tester according to claim 1, wherein the first gas channel (111) and the second gas channel (113) differ from one another in their channel structure by virtue of a roughness of their inner surface.

3. Tester according to at least one of claims 1 to 2, wherein at least one gas channel (111, 113) comprises a temperature control unit which is configured to change a temperature in the interior of this gas channel (111, 113) such that the test gas in the first time period differs in its gas temperature from the test gas in the second time period.

4. Tester according to at least one of claims 1 to 3, wherein the at least one gas generator (105) is designed to conduct a different test gas through the corresponding gas channel (111, 113) during the first time period than during the second time period.

5. Tester according to claim 4, wherein a first test gas has a different diffusion coefficient during the first time period than a second test gas during the second time period.

6. Tester according to at least one of the preceding claims, wherein the test is further carried out by the test unit (101) in at least one further time period.

7. Gas measuring device (100), comprising - at least one analyte-converting chemical gas sensor (103) having a surrounding sensor chamber, - at least one opening region (119) that forms a gas-permeable connection between the sensor chamber and an environment of the gas measuring device, and - at least one tester according to any of the previous claims.

8. Gas measuring device (100) according to claim 7, wherein a first gas channel opening of the first gas channel (111) is closer to the gas sensor (103) than a second gas channel opening of the second gas channel (113).

9. Gas measuring device (100) according to claim 7 or 8, wherein the second gas channel opening is closer to the at least one opening region (119) than the first gas channel opening.

10. Gas measuring device (100) according to any of claims 7 to 9, wherein the gas measuring device (100) comprises at least one computing unit (125) that is designed to receive a signal from the gas sensor (103) and to determine a measured value from it, wherein the computing unit (125) is further designed to define and output test information during the first time period and / or during the second time period, wherein the test information indicates whether the gas measuring device (100) is faulty, and wherein the definition of the test information is based on a comparison between the measured value and a predefined gas sensor threshold value or between a specific measured value profile parameter and a predefined profile parameter.

11. Gas measuring device (100) according to claim 10, wherein the test information indicates whether at least one opening region (119) is blocked and / or whether the gas sensor (103) is functioning.

12. Gas measuring device (100) according to at least one of claims 10 to 11, wherein the corresponding comparison performed by the computing unit (125) depends on a definition of a decay time, a mathematical derivation, a statistical average, a maximum value and / or an integral based on the determined measured value profile.

13. Test method (500) for testing a gas measuring device, wherein the test method (500) comprises the following steps: a) providing a gas measuring device (100) according to any of claim 7 to 12, b) controlling the at least one gas generator (105) such that it conducts at least one test gas into the surrounding sensor chamber of the gas sensor (103) via the gas channel arrangement (109) in a first time period of a test and in a second time period of the test, wherein the at least one test gas is conducted to the sensor chamber via the first gas channel (111) in the first time period and to the sensor chamber via the second gas channel (113) in the second time period, c) determining measured values determined by the gas sensor (103) during the first time period and / or during the second time period, d) defining and outputting test information during the first time period and / or during the second time period, wherein the test information indicates whether the gas measuring device (100) is faulty, and wherein the definition of the test information is based on a comparison between the measured value or a characteristic value calculated therefrom and a predefined gas sensor threshold value or between a specific measured value profile parameter and a predefined profile parameter.