CN210465319U - Thermal conductivity gas analyzer - Google Patents
Thermal conductivity gas analyzer Download PDFInfo
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- CN210465319U CN210465319U CN201921356265.XU CN201921356265U CN210465319U CN 210465319 U CN210465319 U CN 210465319U CN 201921356265 U CN201921356265 U CN 201921356265U CN 210465319 U CN210465319 U CN 210465319U
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Abstract
The utility model discloses a thermal conductivity gas analyzer, which comprises an air chamber, an inner chamber arranged in the air chamber, a semiconductor thermal conductivity sensor arranged in the inner chamber and an airflow passage arranged at one end of the inner chamber; the air flow passage is provided with an air inlet hole and an air outlet hole which are respectively communicated with one end of the inner cavity, the air inlet hole is arranged at the air inlet side of the air flow passage, and the air outlet hole is arranged at the air outlet side of the air flow passage; the sensor module is connected with the data analysis module through a lead; the other end of the inner cavity is sealed by sealant. Sample gas gets into airflow channel by airflow channel's the side of admitting air, then in getting into the inner chamber through the last gas vent reposition of redundant personnel of airflow channel, has reduced the influence that the sensor module received the air current change, simultaneously, this application utilizes semiconductor thermal conductivity sensor to replace the heating wire, and stability is good, and the good reliability, sensitivity is high, and response speed is fast, and temperature characteristic is good, and when using, the drift is little, does not need frequent calibration, can improve thermal conductivity gas analyzer's performance greatly.
Description
Technical Field
The utility model relates to a thermal conductivity gas analyzer.
Background
The thermal conductivity gas analyzer calculates the contents of certain components by measuring the thermal conductivity of mixed gas according to the principle that different gases have different thermal conductivity.
Generally, a thermal conductivity gas sensor uses an electric heating wire as a sensing element for sensing the change of the thermal conductivity of gas. The analyzer of the thermal conductivity gas sensor adopting the electric heating wire needs two sensing elements, one is used for measurement, the other is used for reference, when the analyzer works, the resistance value of the sensing element used for reference does not change, and the resistance value of the sensing element used for measurement changes along with the change of the thermal conductivity coefficient of the gas. The resistance variation of the gas sensor can be easily measured through a Wheatstone bridge, and the concentration of the gas to be measured can be further calculated. As shown in fig. 1, wherein R3 is a measurement sensor located in the sample gas flow path; r4 is a reference sensing element sealed in a reference gas; r1, R2 are fixed value resistors. R1, R2, R3 and R4, together with a constant voltage source or constant current source, form a Wheatstone bridge.
However, the heating wire needs to be cut, welded, coated, and packaged manually, the manufacturing process is complex, and the consistency is poor due to a plurality of influencing factors. The resistance and temperature coefficient of the two sensing elements used for measurement and reference need to be highly matched otherwise drift will be caused. In addition, in order to strengthen the strength of the electric heating wire, glass or other materials need to be coated on the surface of the electric heating wire, so that the response speed of the sensitive element is slow, and the sensitivity is low.
SUMMERY OF THE UTILITY MODEL
The utility model aims at providing a thermal conductivity gas analyzer to it is slow to solve present thermal conductivity gas sensor response speed, and sensitivity is low and stable problem.
In order to solve the technical problem, the utility model provides a thermal conductivity gas analyzer, which comprises an air chamber, an inner chamber arranged in the air chamber and an airflow passage arranged at one end of the inner chamber; the air flow passage is provided with an air inlet hole and an air outlet hole which are respectively communicated with one end of the inner cavity, the air inlet hole is arranged at the air inlet side of the air flow passage, and the air outlet hole is arranged at the air outlet side of the air flow passage; a sensor module is arranged in the inner cavity and comprises a heat conducting gas sensor and a temperature sensor; the other end of the inner cavity is sealed through a sealant.
Further, the aperture of the air inlet hole is smaller than that of the air outlet hole.
Furthermore, the thermal conductivity gas sensor is a semiconductor thermal conductivity sensor, and the semiconductor thermal conductivity sensor integrates a sensitive element on a semiconductor base by adopting an MEMS technology.
Furthermore, the air inlet end of the airflow channel is filled with a breathable filler.
Further, the breathable filler is made of a metal material.
Further, the sealant is potting heat-conducting glue.
Further, the thermal conductivity gas analyzer also comprises a heating device for preheating gas entering the gas flow passage, and the heating device controls heating through a constant temperature control circuit.
Furthermore, the sensor module is connected with the data analysis module through a wire, the data analysis module comprises a signal processing module and a control circuit, the input end of the signal processing module is respectively connected with the thermal conductivity gas sensor and the temperature sensor, the output end of the signal processing module is connected with the input end of the control circuit, and the output end of the control circuit is respectively connected with the display and the constant temperature control circuit.
Further, the thermal conductivity gas analyzer also comprises a communication interface connected with the output end of the control circuit.
Further, the thermal conductivity gas analyzer also comprises an alarm circuit connected with the output end of the control circuit.
The utility model has the advantages that: in the working process, the sample gas enters the airflow passage from the air inlet side of the airflow passage, and then is shunted into the inner cavity through the air inlet hole in the airflow passage, so that the influence of airflow change received by the sensor module is reduced, the working stability of the sensor can be ensured, and the reliability is high. Moreover, the semiconductor thermal conductivity sensor is utilized to replace a thermal conductivity sensor made of an electric heating wire, the thermal conductivity sensor is good in qualitative property, strong in reliability, high in sensitivity, fast in response speed and good in temperature characteristic, when the thermal conductivity sensor is used, the drift is small, frequent calibration is not needed, and the performance of the online thermal conductivity gas analyzer can be greatly improved.
Drawings
The accompanying drawings, which are included to provide a further understanding of the application and are incorporated in and constitute a part of this application, illustrate embodiment(s) of the application and together with the description serve to explain the application and not to limit the application. In the drawings:
fig. 1 is a schematic circuit diagram of a wheatstone bridge according to an embodiment of the present invention.
Fig. 2 is a schematic structural diagram of an embodiment of the present invention.
Fig. 3 is a block diagram of a data analysis module according to an embodiment of the present invention.
Wherein: 1. an air chamber; 2. an inner cavity; 21. an air inlet; 22. an exhaust hole; 3. an air intake side; 31. a breathable filler; 4. a sensor module; 41. a wire; 5. an exhaust side; 6. and (5) encapsulating heat-conducting glue.
Detailed Description
The thermal conductivity gas analyzer shown in fig. 2 comprises a gas chamber 1, an inner cavity 2 arranged in the gas chamber 1, a sensor module 4 installed in the inner cavity 2, and a gas flow passage arranged at one end of the inner cavity 2; an air inlet 21 and an air outlet 22 which are respectively communicated with one end of the inner cavity 2 are arranged on the air flow passage, the air inlet 21 is arranged on the air inlet side 3 of the air flow passage, and the air outlet 22 is arranged on the air outlet side 5 of the air flow passage.
Sample gas gets into the air current passageway by air current passageway's air inlet side 3, then through air vent 21 reposition of redundant personnel entering inner chamber 2 on the air current passageway, has reduced sensor module 4 and has received the influence that the air current changed, can guarantee that sensor work is more stable, the good reliability. In addition, the aperture of the air inlet 21 is smaller than that of the air outlet 22, and sample air enters the inner cavity 2 from the air inlet 21 with a small aperture and is exhausted from the air outlet 22 with a large aperture, so that the throttling effect can be achieved, the influence of flow change on the sensor is further reduced, and the sensor is protected from being impacted by atmospheric flow.
In particular, the air flow path may be configured as a U-shape, and includes a first vertical section, a planar section and a second vertical section, which are sequentially connected, and the air inlet 21 and the air outlet 22 are disposed at the planar section, which may facilitate the arrangement on the one hand, so that the structure is convenient for packaging, and may further reduce the impact of the air flow on the sensor.
The sensor module 4 comprises a thermal conductivity gas sensor and a temperature sensor, and the other end of the inner cavity 2 is sealed through a sealant. The sensor module 4 is connected with the data analysis module through a lead 41, and data collected by the sensor module 4 is led out through the lead 41 and then fixed and sealed through the encapsulating heat-conducting glue 6.
The temperature sensor is used for measuring the temperature of the semiconductor thermal conductivity sensor, the thermal conductivity gas sensor is a semiconductor thermal conductivity sensor, the semiconductor thermal conductivity sensor integrates a sensitive element on a semiconductor base by adopting an MEMS (micro-electromechanical systems) technology, and the semiconductor thermal conductivity sensor has the advantages of good consistency, high stability, strong reliability, small long-term drift, high sensitivity and high response speed, and can be used for small-range measurement; the stability is good, the reliability is strong, the drift is small during long-term measurement, and frequent calibration is not needed.
The air inlet end of the airflow passage is filled with the air permeable filler 31, and the air permeable filler 31 can disperse the airflow in the airflow passage in the machine. Particularly, the air-permeable packing 31 is made of metal material, the sample gas is preheated by the heat conductivity of the metal material, and the air-permeable metal packing can increase the contact area between the sample gas and the gas chamber 1, so that the sample gas can be fully preheated in the air inlet end of the gas flow path and reach the same temperature as the temperature of the sensor before reaching the inner cavity 2 of the gas chamber 1.
As shown in fig. 3, the data analysis module includes a signal processing module and a control circuit, the input end of the signal processing module is connected with the thermal conductivity gas sensor and the temperature sensor, the output end of the signal processing module is connected with the input end of the control circuit, and the output end of the control circuit is connected with the display, the communication interface and the alarm circuit. The control circuit receives the digital signal from the signal processing module, calculates the concentration of the gas to be detected through a built-in program, displays the concentration on the display screen, outputs corresponding current at the same time, controls the output of the alarm circuit, and the RS485 communication interface is used for communicating with an upper computer. The display module provides a man-machine interface, and the instrument is subjected to operation such as range setting, calibration and the like through a keyboard. The whole data analysis module is powered by an AC/DC power supply, the AC/DC power supply is used for converting 220V unidirectional alternating current power supply into 24V direct current power supply, and the ripple wave of the AC/DC power supply is less than 50 mV.
The signal processing module comprises a signal conditioning circuit, an amplifying circuit, a filtering circuit and an analog-to-digital conversion circuit which are sequentially connected and is used for converting the sensor signal into a digital signal. The signal conditioning circuit, the amplifying circuit and the filter circuit are formed by a high-precision zero-drift operational amplifier and a high-precision low-temperature drift resistor; the analog-to-digital conversion circuit is composed of a high-precision low-temperature drift voltage reference and a high-resolution analog-to-digital converter, and is used for simultaneously converting a sensor signal and a temperature signal into digital signals for the control circuit to collect, and the temperature signal is used for constant temperature control.
The thermal conductivity gas analyzer also comprises a heating device for preheating gas entering the gas flow passage, wherein the heating device is controlled and heated by a constant temperature control circuit, and the input end of the constant temperature control circuit is connected with the output end of the control circuit and used for controlling the temperature of the sensor module 4 to be 60 +/-0.1 ℃.
Finally, although the present invention has been described in detail with reference to the preferred embodiments, it should be understood by those skilled in the art that the present invention can be modified or replaced by other means without departing from the spirit and scope of the present invention, which should be construed as limited only by the appended claims.
Claims (10)
1. A thermal conductivity gas analyzer is characterized by comprising a gas chamber, an inner cavity arranged in the gas chamber, a sensor module arranged in the inner cavity and an airflow passage arranged at one end of the inner cavity; the air flow passage is provided with an air inlet hole and an air outlet hole which are respectively communicated with one end of the inner cavity, the air inlet hole is arranged at the air inlet side of the air flow passage, and the air outlet hole is arranged at the air outlet side of the air flow passage; the sensor module comprises a thermal conductivity gas sensor and a temperature sensor; the other end of the inner cavity is sealed through a sealant.
2. A thermal conductivity gas analyzer as claimed in claim 1, wherein the diameter of the gas inlet hole is smaller than the diameter of the gas outlet hole.
3. A thermally conductive gas analyzer as claimed in claim 1 or 2 wherein the thermal conductive gas sensor is a semiconductor thermal conductive sensor that employs MEMS technology to integrate a sensing element on a semiconductor base.
4. A thermal conductivity gas analyzer as claimed in claim 3, wherein the gas inlet end of the gas flow path is filled with a gas permeable filler.
5. A thermal conductivity gas analyzer as claimed in claim 4, wherein the gas permeable filler is made of metal material.
6. A thermal conductivity gas analyzer as claimed in claim 1, wherein the sealant is potting thermal conductive glue.
7. A thermally conductive gas analyzer as claimed in claim 1 further comprising heating means for preheating the gas entering the gas flow path, the heating means being controlled by a thermostatic control circuit.
8. A thermal conductivity gas analyzer as claimed in claim 7, wherein the sensor module is connected to the data analysis module through a wire, the data analysis module comprises a signal processing module and a control circuit, the input end of the signal processing module is connected to the thermal conductivity gas sensor and the temperature sensor, respectively, the output end of the signal processing module is connected to the input end of the control circuit, and the output end of the control circuit is connected to the display and the thermostatic control circuit, respectively.
9. A thermally conductive gas analyzer as claimed in claim 8 further comprising a communication interface coupled to an output of the control circuit.
10. A hot gas conductivity analyzer as claimed in claim 8 or 9, further comprising an alarm circuit connected to an output of the control circuit.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201921356265.XU CN210465319U (en) | 2019-08-20 | 2019-08-20 | Thermal conductivity gas analyzer |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201921356265.XU CN210465319U (en) | 2019-08-20 | 2019-08-20 | Thermal conductivity gas analyzer |
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| Publication Number | Publication Date |
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| CN210465319U true CN210465319U (en) | 2020-05-05 |
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| CN201921356265.XU Active CN210465319U (en) | 2019-08-20 | 2019-08-20 | Thermal conductivity gas analyzer |
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Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110412070A (en) * | 2019-08-20 | 2019-11-05 | 重庆川仪分析仪器有限公司 | Online catharometer |
| CN111999338A (en) * | 2020-07-22 | 2020-11-27 | 中国科学院上海微***与信息技术研究所 | Miniature thermal conductivity gas sensor |
| CN113203769A (en) * | 2021-04-15 | 2021-08-03 | 电子科技大学 | High-air-tightness micro thermal conductivity detector and manufacturing method thereof |
-
2019
- 2019-08-20 CN CN201921356265.XU patent/CN210465319U/en active Active
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110412070A (en) * | 2019-08-20 | 2019-11-05 | 重庆川仪分析仪器有限公司 | Online catharometer |
| CN111999338A (en) * | 2020-07-22 | 2020-11-27 | 中国科学院上海微***与信息技术研究所 | Miniature thermal conductivity gas sensor |
| CN111999338B (en) * | 2020-07-22 | 2022-07-22 | 中国科学院上海微***与信息技术研究所 | Miniature thermal conductivity gas sensor |
| CN113203769A (en) * | 2021-04-15 | 2021-08-03 | 电子科技大学 | High-air-tightness micro thermal conductivity detector and manufacturing method thereof |
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