GAS MEASURING DEVICE

Abstract

A gas measuring device (100, 400). The gas measuring device (100, 400) includes a chemical gas sensor (103, 417) and a testing unit (101). The testing unit (101) includes a base, a gas duct arrangement arranged at the base with a first gas duct (111, 401) and with at least one additional gas duct (113, 405) and at least one electrochemical gas generator (105, 403, 407). The at least one gas generator (105, 403, 407) is configured to send at least one test gas into the first gas duct (111, 401) in a first state and into the at least one additional gas duct (113, 405) in an additional state. The first gas duct (111, 401) and the at least one additional gas duct (113, 405) are each configured to send at least one gas to the gas sensor (103, 417). The first gas duct (111, 401) differs from the at least one additional gas duct (113, 405).

Claims

1. A gas measuring device comprising: a chemical gas sensor comprising: a sensor chamber, the gas sensor being configured to react an analyte enclosed within the sensor chamber; and an opening area, which forms a gas-permeable connection between the sensor chamber and an environment of the gas measuring device; and a testing unit comprising: a gas duct arrangement; and a gas generator configured to send test gas into the sensor chamber of the gas sensor in a first time period of a test of the testing unit and in a second time period of the test via the gas duct arrangement, wherein: a transportation of test gas has a different transportation characteristic during the first time period than during the second time period; and the different transportation characteristic is based on a gas duct structure of the gas duct arrangement, or is based on a property of the test gas transported, or is based both on a gas duct structure of the gas duct arrangement and a property of the test gas transported.

2. A gas measuring device in accordance with claim 1, wherein: the gas duct arrangement comprises a first gas duct and a second gas duct; test gas is sent to the sensor chamber via the first gas duct during the first time period; and test gas is sent to the sensor chamber via the second gas duct during the second time period.

3. A gas measuring device in accordance with claim 2, wherein: the first gas duct has a first gas duct structure; the second gas duct has a second gas duct structure; and the first gas duct structure differs from the second gas duct structure.

4. A gas measuring device in accordance with claim 3, wherein a first gas duct opening of the first gas duct is located closer to the gas sensor than a second gas duct opening of the second gas duct.

5. A gas measuring device in accordance with claim 3, wherein the second gas duct opening is located closer to the at least one opening area than the first gas duct opening.

6. A gas measuring device in accordance with claim 3, wherein the first gas duct structure has an inner surface with a roughness that is different from a roughness of an inner surface of the second gas duct structure.

7. A gas measuring device in accordance with claim 1, wherein: the gas duct arrangement comprises a first gas duct and a second gas duct; and one of the gas ducts further comprises a temperature control unit configured to change a temperature in an interior of the one of the gas ducts such that a gas temperature of test gas in the first time period differs from a gas temperature of test gas in the second time period.

8. A gas measuring device in accordance with claim 1, wherein the gas generator is configured to send a different test gas through the gas duct structure during the first time period than during the second time period.

9. A gas measuring device in accordance with claim 8, wherein: the test gas comprises a first test gas sent during the first time period and a second test gas sent during the second time period; and the first test gas has a different diffusion coefficient than the second test gas.

10. A gas measuring device in accordance with claim 1, wherein the testing unit provides a test comprising the transportation of the test during the first time period and the second time period and further provides at least one additional time period during the test.

11. A gas measuring device in accordance with claim 1, wherein: the gas measuring device further comprises a computing unit configured to receive a signal of the gas sensor and to determine a measured value based on the signal; the computing unit is further configured to determine and to output test information during the first time period or during the second time period or during both the first time period and the second time period; the test information indicates whether the gas measuring device is defective; and the determination of the test information is based on a comparison between the measured value and a predefined gas sensor threshold value or between a determined measured value relationship parameter and a predefined relationship parameter.

12. A gas measuring device in accordance with claim 11, wherein the test information indicates whether the at least one opening area is clogged or whether the gas sensor is operable; or both whether the at least one opening area is clogged and whether the gas sensor is operable.

13. A gas measuring device in accordance with claim 11, wherein: the corresponding comparison carried out by the computing unit depends on a determination of at least one of a decay time, a mathematical derivation, a statistical mean, a maximum and an integral; and the determination is based on the measured value relationship determined.

14. A tester for a gas measuring device, the tester comprising: a testing unit comprising: a gas duct arrangement comprising a gas duct structure; and a gas generator configured to send test gas into a sensor chamber of a gas sensor in a first time period of a test of the testing unit and in a second time period of the test of the testing unit via the gas duct arrangement, wherein: a transportation of test gas has a different transportation characteristic during the first time period than during the second time period; and the different transportation characteristic is based on the gas duct structure, or is based on a property of the test gas transported, or is based both on the gas duct structure and a property of the test gas transported; and a connection interface configured to provided a reversible operative connection with the gas sensor.

15. A tester in accordance with claim 14, wherein: the gas duct arrangement comprises a first gas duct and a second gas duct; test gas is sent via the first gas duct during the first time period; and test gas is sent via the second gas duct during the second time period.

16. A tester in accordance with claim 15, wherein: the first gas duct has a first gas duct structure; the second gas duct has a second gas duct structure; and the first gas duct structure differs from the second gas duct structure.

17. A tester in accordance with claim 14, wherein: the gas duct arrangement comprises a first gas duct and a second gas duct; and one of the gas ducts further comprises a temperature control unit configured to change a temperature in an interior of the one of the gas ducts such that a gas temperature of test gas in the first time period differs from a gas temperature of test gas in the second time period.

18. A tester in accordance with claim 14, wherein the gas generator is configured to send a different test gas through the gas duct arrangement during the first time period than during the second time period.

19. A tester in accordance with claim 18, wherein: the test gas comprises a first test gas sent during the first time period and a second test gas sent during the second time period; and the first test gas has a different diffusion coefficient than the second test gas.

20. A testing process for testing a gas measuring device, wherein the testing process comprises the steps of: providing a gas measuring device comprising: a chemical gas sensor comprising: a sensor chamber, the sensor reacting an analyte enclosed within the sensor chamber; and an opening area, which forms a gas-permeable connection between the sensor chamber and an environment of the gas measuring device; and a testing unit comprising: a gas duct arrangement; and a gas generator configured to send test gas into the sensor chamber of the gas sensor in a first time period of a test of the testing unit and in a second time period of the test via the gas duct arrangement, wherein: a transportation of test gas has a different transportation characteristic during the first time period than during the second time period; and the different transportation characteristic is based on a gas duct structure of the gas duct arrangement, or is based on a property of the test gas transported, or is based both on a gas duct structure of the gas duct arrangement and a property of the test gas transported; actuating the gas generator such that the gas generator sends test gas into the enclosing sensor chamber of the gas sensor via the gas duct arrangement during a first time period of a test and during a second time period of the test; determining measured values during the first time period, or determining measured values during the second time period or determining measured values during both the first time period and the second time period; and determining test information and outputting test information during the first time period or during the second time period or during both the first time period and the second time period, wherein: the test information indicates whether the gas measuring device is defective; and the determination of the test information is based on a comparison between the measured value or a parameter calculated therefrom and a predefined gas sensor threshold value or between a determined measured value relationship parameter and a predefined relationship parameter.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0095] In the drawings:

[0096] FIG. 1 is a schematic cut-away side view of an embodiment of the gas measuring device according to the present invention;

[0097] FIG. 2 is a comparison of measured data, which were determined with the use of the gas measuring device from FIG. 1 during the admission of gas through a first gas duct and measured data that were determined during an admission of gas through a second gas duct;

[0098] FIG. 3 is a comparison of measured data that can be used to determine the effect of an ambient velocity with the use of the gas measuring device from FIG. 1;

[0099] FIG. 4 is another possible embodiment of the gas measuring device of the present invention; and

[0100] FIG. 5 is flow diagram showing the course of a possible embodiment of the process according to the present invention.

DESCRIPTION OF PREFERRED EMBODIMENTS

[0101] Referring to the drawings, FIG. 1 shows a gas measuring device 100 in a cut-away side view. The gas measuring device comprises a testing unit 101 and a gas sensor 103.

[0102] The testing unit 101 comprises an especially chemical gas generator 105 for reacting an analyte of a test gas for testing the gas measuring device 100.

[0103] The gas generator 105 comprises a generator electrode in a first generator chamber 107 and a counterelectrode. Furthermore, an additional generator chamber 109 is provided. Provisions may be made, in particular, for the counterelectrode to be used jointly by a plurality of gas generators/generator chambers.

[0104] The first generator chamber 107 is in contact with a first gas duct 111 via a first gas discharge opening 129, so that test gas generated by the gas generator 105 flows through the first gas discharge opening 129 and into the first gas duct 111. In order to prevent a discharge of electrolyte possibly being stored in the first generator chamber 107 into the first gas duct 111, the first gas discharge opening 129 comprises a gas-permeable diaphragm, which is permeable for the test gas and impermeable for the test gas.

[0105] The additional generator chamber 109 is in contact with a second gas duct 113 via an additional gas discharge opening 131, so that test gas generated by the optional additional gas generator and/or by an optional additional generator electrode flows through the additional gas discharge opening 131 into the second gas duct 113, to prevent electrolyte possibly being stored in the additional generator chamber 109, the additional gas discharge opening 131 comprises a selectively gas-permeable diaphragm, which is permeable for the test gas and impermeable for the electrolyte.

[0106] The testing unit 101 is connected in this case permanently to the gas sensor 103. In addition, the testing unit 101 is configured such that the testing unit 101 has an interface for communicative and/or mechanical connection to the gas sensor 103.

[0107] The testing unit 101 may be configured as a circular base, at which the first gas duct 11 and the second gas duct 113 are arranged or into which the first gas duct 111 and the second gas duct 113 are integrated.

[0108] The first gas duct 111 further comprises a first chamber 115.

[0109] The second gas duct 113 further comprises an additional chamber 117 with an opening area 119, through which the chamber 117 is in contact with an environment via a filter at the opening area 119, so that ambient medium, e.g., air, can flow into the chamber 117 and test gas can flow out of the chamber 117. The first chamber 115 and the additional chamber 117 are fluidally in exchange with one another, so that gases can flow from the additional chamber 117 into the first chamber 115. The flow motion between the first chamber 115 and the additional chamber 117 is led through and/or defined by flow guiding devices 123. The first chamber 115 and the additional chamber 117 form a sensor chamber enclosing the gas sensor 103 in the exemplary embodiment shown.

[0110] The first gas duct 111 has a duct structure that differs from the duct structure of the second gas duct 113. The first gas duct 111 is longer in this case than the second gas duct 113, so that a distance between an end of the first gas duct 111 and an inlet area 121 of the gas sensor 103 is shorter than a distance between an end of the second gas duct 113 and the inlet area 121 of the gas sensor 103.

[0111] Furthermore, the testing unit 101 comprises a first computing unit 125, which is configured as a control module to control the gas generator 105 and the gas sensor 103. The first computing unit 125 can be in connection for this purpose with the gas generator 105 and with the gas sensor 103 via a communication interface, such as an operative connection interface that can be connected, disconnected and reconnected, for example, a cable or a wireless connection. The first computing unit 125 may comprise one or more processors, which are configured for controlling the gas generator 105 and the gas sensor each individually or jointly.

[0112] For testing the gas measuring device 100, the gas generator 105 is actuated by the first computing unit 125 such that in a first state, during a first time period of a test of the testing unit 101, the gas generator 105 admits test gas into the gas sensor 103 by means of the first gas duct 111. In a second state, during a second time period of the test, the first computing unit 125 actuates the gas generator 105 such that this admits test gas into the gas sensor 103 by means of the second gas duct 113.

[0113] Since the first gas duct 111 and the second gas duct 113 differ from one another in terms of their duct structures, the test gas flows with different transportation characteristics through the first gas duct 111 and through the second gas duct 113.

[0114] The test gas is discharged in this case during the first time period at the end of the first gas duct 111 at a short distance from the inlet area 121 of the gas sensor 103. The test gas correspondingly flows rapidly, i.e., directly to the gas sensor 103, as a result of which an effect of disturbance variables, for example, inflows of an ambient medium from the environment and outflows of test gas into the environment, is minimal A measurement of the test gas by the gas sensor 103 is therefore subject during the first time period to an effect of disturbance variables that is reduced relative to the second time period. Measured values determined by the gas sensor 103 during the first state are correspondingly especially valid concerning the functionality of the gas sensor 103.

[0115] In the additional state during the second time period, the test gas is discharged at the end of the second gas duct 113 at a great distance from the sensor inlet 121 and in the proximity in space of the opening area 119.

[0116] Based on the long diffusion paths combined with a long diffusion time, measured values determined by the gas sensor 103 during this second time period are especially susceptible to disturbing effects caused by the inflow of an ambient medium and/or by an outflow of test gas. The outflow of the test gas, in particular, represents an important removal path of the test gas generated, because the outlet opening of 113 is located in the immediate proximity of the opening area 119 with the gas inlet opening. Correspondingly, the measured values determined during the second time period are especially affected by and are valid concerning the detection of a clogging of the opening area 119.

[0117] Provisions are correspondingly made for the functionality of the gas sensor 103 to be tested on the basis of measured values determined during the first time period and for the functionality or the permeability of the opening area 119 to gases to be tested on the basis of measured values determined during the second time period.

[0118] In addition to the first computing unit 125, a second computing unit 127, which is configured as an analysis module and is in communicative connection with the gas sensor 103 via a communication interface, for example, a cable or a wireless interface, may optionally also be used for the analysis of measured values determined by the gas sensor. The first computing unit 125 may, of course, also be used for the analysis of measured values determined by the gas sensor 103.

[0119] In one exemplary embodiment, not shown, a different test gas is sent through the corresponding gas duct, i.e., for example, through the first gas duct, during the first time period than during the second time period. The two different test gases preferably differ from one another in their diffusion coefficients, so that the transportation characteristic is different during the first time period from that seen during the second time period already due to the different test gases.

[0120] Only a single gas duct is provided in another exemplary embodiment to provide the two time ranges with different transportation characteristics of the test gas transportation. The different transportation characteristics are based in this case on different test gas properties, for example, on different test gases used and/or on different test gas temperatures used.

[0121] FIG. 2 shows a diagram 200, having an ordinate 201 indicating a sensor signal in [ppm] and having an abscissa 203 indicating a time in [hh:mm:ss].

[0122] A curve (time relationship or time course) 205 represents measured values that were determined by the gas sensor 103 during an admission of test gas in the first state during the first time period from the first gas duct 111 and while the opening area 119 was clogged for gases, i.e., impermeable to gases.

[0123] A curve (time relationship or time course) 207 represents measured values that were determined by the gas sensor 103 during an admission of test gas in the first state during the first time period from the first gas duct 111 and while the opening area 119 was permeable to gases, i.e., while opening area 119 was not clogged.

[0124] Furthermore, FIG. 2 shows a diagram 220, which shows a sensor signal in [ppm] on its ordinate 221 and the time in [hh:mm:ss] on its abscissa 223.

[0125] A curve 225 represents measured values that were determined during the admission of test gas in the additional state during the second time period from the second gas duct 113 and while the opening area 119 was clogged for gases, i.e., impermeable to gases.

[0126] A curve 227 shows measured values that were determined by the gas sensor 103 during an admission of test gas in the additional state during the second time period from the second gas duct 113 and while the opening area 119 was permeable to gases, i.e., while opening area 119 was not clogged.

[0127] A comparison of the curves 205 and 207 with the curves 225 and 227 shows that the clogging of the opening area 119 during the admission of test gas through the second gas duct 113 according to the curve 227 differs markedly from the curve 225. Furthermore, the clogging of the opening area 119 during the admission of test gas through the first gas duct 111 according to the curve 205 differs very slightly from the curve 207. Correspondingly, a distinction can clearly be made on the basis of measured values determined by the gas sensor 103 during the additional state between a state in which the opening area 119 is clogged and a state in which the opening is permeable to gases.

[0128] Measured values determined by the gas sensor 103 during the second time period can therefore be used to detect a clogged state in order to determine, i.e., to calculate or to estimate a decay time, for example, a half-time or another value at a predefined time after the start of the admission of gas. Should a difference in the decay time from a predefined reference value be greater than a predefined clogging threshold value, it can be assumed that the opening area 119, especially a filter within the opening area 119, is clogged. Provisions are correspondingly made for this case for the computing unit 125 to mark the gas measuring device 100 as being clogged and, for example, to store a corresponding error message in an error memory.

[0129] A decay time can be calculated, in particular, for example, by an area under a maximum between a predefined start time and a predefined stop time.

[0130] FIG. 3 shows a diagram 300, which shows a unitless relative sensor signal on its ordinate 301. This sensor signal changes due to the effect of the wind for different wind speeds, which were plotted on the abscissa 303 in [m/sec].

[0131] A curve 305 is based on measured values that were determined by the gas sensor 103 during the admission of test gas through the second gas duct 113.

[0132] A curve 307 is based on measured values that were determined by the gas sensor 103 during the admission of test gas through the first gas duct 111.

[0133] It can be clearly seen that a distance between the curve 305 and the curve 307 increases with increasing wind speed. This means that a corresponding wind speed can be inferred from a distance between the curve 305 and the curve 307 and that the device used for the curve 307 is markedly less subject to the effect of wind and is therefore better suited for checking the sensitivity of the sensor 301. This relationship may be used, for example, to deactivate a warning function of the gas measuring device 100 when wind speeds that are higher than a predefined threshold value are determined.

[0134] FIG. 4 shows a gas measuring device 400.

[0135] The gas measuring device 400 comprises a first gas duct 401, which is configured here as a chamber and in which a first gas generator 403 is arranged, and a computing unit 419.

[0136] The gas measuring device 400 comprises, furthermore, a second gas duct 405, which is configured here as a chamber and in which an additional gas generator 407 is arranged.

[0137] The first gas duct 401 is in fluid contact with the second gas duct 405 via gas transfer openings 409, so that an exchange of gas between the first gas duct 401 and the second gas duct 405 is possible.

[0138] The second gas duct 405 is in fluid contact with an environment via an opening 411, which acts as a sensor inlet and forms in this sense the opening area for the gas measuring device 400, so that a direct, immediate gas exchange is possible between the environment and the second gas duct 405.

[0139] The first gas duct 401 is in contact with a sensor diaphragm 413, which separates an electrolyte of a gas sensor 417 of the gas measuring device from the first gas duct 401.

[0140] Since the first gas duct 401 is not directly in contact with an environment, a test gas provided by the first gas generator 403 is affected only minimally by ambient conditions of the gas measuring device 400, for example, by wind. The first gas duct 401 is correspondingly especially advantageously suitable for testing the gas sensor 417.

[0141] In order to rule out a false negative error message, which falsely marks the gas sensor 417 as being defective in case measured values of the gas sensor 417 show upon the admission of test gas to the interior space 415 of a sensor by the first gas generator 403 that the gas sensor 417 is to be marked as being defective, the first gas generator 403 can be tested by means of the additional gas generator 407.

[0142] To test the first gas generator 403, provisions are made for a test gas provided by the additional gas generator 407 to be admitted to the gas sensor 417. In case the gas sensor 417 is not to be marked as being defective upon admission of test gas by the additional gas generator 407, provisions are made for the gas sensor 417 to be marked as error-free and the first gas generator 403 as being defective. A computing unit of the gas measuring device 400 can change or generate for this purpose a corresponding error message in an error memory of the gas measuring device 400 or in a memory of the computing unit.

[0143] FIG. 5 shows the course of the process 500 described.

[0144] The process 500 starts with a provision step 501 for providing a possible embodiment of the gas measuring device being presented. For example, a possible configuration of the tester being presented can be connected for this purpose to a gas sensor to obtain a possible configuration of the gas measuring device being presented.

[0145] At least one gas generator of the gas measuring device is actuated in an actuation step 503 such that it admits the at least one test gas into the enclosing sensor chamber of the gas sensor in a first time period of a test and in a second time period of the test via the gas duct device.

[0146] In a determination step 505, which takes place simultaneously with the actuation step 503 at least from time to time, 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 carried out by a computing unit of the gas measuring device reading out respective measured values determined by the gas sensor and storing them in a working memory.

[0147] The gas measuring device is marked in a marking step 507 as being defective if the analysis logarithms determine a deviation from the desired state. The marking takes place according to the present invention by a determination and output of test information during the first time period and/or during the second time period, the test information indicating whether the gas measuring device is defective, and wherein the determination of the test information is based on a comparison between the measured value and a predefined gas sensor threshold value or between a determined measured value curve parameter and a predefined curve parameter.

[0148] While specific embodiments of the invention have been shown and described in detail to illustrate the application of the principles of the invention, it will be understood that the invention may be embodied otherwise without departing from such principles.

LIST OF REFERENCE NUMBERS

[0149] 100, 400 Gas measuring device [0150] 101 Testing unit [0151] 103, 417 Gas sensor [0152] 105 Gas generator [0153] 107 first generator chamber [0154] 109 additional chamber [0155] 111, 401 First gas duct [0156] 113, 405 Second gas duct [0157] 115 First chamber [0158] 117 Additional chamber [0159] 119 Opening area [0160] 121 Inlet area [0161] 123 Flow guiding device [0162] 125 First computing unit [0163] 127 Second computing unit [0164] 129 First gas discharge opening [0165] 131 Additional gas discharge opening [0166] 200, 220, 300 Diagram [0167] 201, 221, 301 Ordinate [0168] 203, 223, 303 Abscissa [0169] 205, 207, 225 Curve [0170] 227, 305, 307 [0171] 403 First gas generator [0172] 407 Additional gas generator [0173] 409 Gas transfer openings [0174] 411 Opening [0175] 413 Sensor diaphragm [0176] 415 Sensor interior space [0177] 419 Computing unit [0178] 500 Process [0179] 501, 503, 504, 507 Process step