CN207675682U - Be self-regulated thermal conductivity gas sensor and gas-detecting device - Google Patents
Be self-regulated thermal conductivity gas sensor and gas-detecting device Download PDFInfo
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- CN207675682U CN207675682U CN201721907109.9U CN201721907109U CN207675682U CN 207675682 U CN207675682 U CN 207675682U CN 201721907109 U CN201721907109 U CN 201721907109U CN 207675682 U CN207675682 U CN 207675682U
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Abstract
The utility model is related to a kind of thermal conductivity gas sensor and gas-detecting devices, more particularly to a kind of self-regulation thermal conductivity gas sensor and gas-detecting device, including shell, signal processing module, measurement sensor, air inlet pipeline and outlet pipe, the air inlet pipeline connects the outlet pipe by the measurement sensor, the measurement sensor includes thermistor, the two stage amplifer circuit that specially positive feedback system constant gain is 1, the thermistor is connected between two amplifiers, so that the resistance value of amplifier equilibrium temperature sensing module is setting value, in this way when tested gas causes the temperature of temperature sensor to change, the resistance value of thermistor can be adjusted to setting value by operational amplifier circuit automatically, avoid the temperature drift errors brought because its work resistance value is indefinite.The embodiment of the utility model is simple in structure, of low cost, while realizing the self-regulating function of the operating temperature and resistance value to thermistor.
Description
Technical field
The utility model is related to a kind of thermal conductivity gas sensor and gas-detecting devices, and in particular to a kind of self-regulating heat
Conduction gas sensor and gas-detecting device.
Background technology
In recent years with the development of semiconductor technology, based on heat-conducted gas sensor using more and more extensive.It is heat-conducted
Gas sensor be the difference based on gas with various thermal conductivity, measure a kind of device of gas concentration.It can will be with gas kind
Class and concentration dependent information are converted into electric signal, have the following advantages that：Detection range is big, good operating stability, service life
The problem of length, there is no catalyst agings, has higher stability and reliability, can detect almost all of gas, and
The detection of gas concentration can be realized in the case of aerobic or anaerobic in test environment.These good characteristics are many other
Not available for gas sensor.But thermal conductivity gas sensor there is also accuracy of detection in gaseous detection applications poor, temperature
It drifts about the defects of big, limits the extensive use of thermal conductivity gas sensor.
In document《Using the new method research of thermal conductivity sensor detection gas concentration》(《Sensing technology journal》2006. yellow
Be brave etc.) in propose a kind of detection method for keeping senor operating temperature constant in detection process, to solve thermal conductivity gas
Body sensor not high defect of precision caused by the sensor self-temperature drift of semiconductor structure.The program uses three
Arm resistance and thermal conductivity sensor collectively constitute an electric bridge, common using adjuster, servo circuit, variable current source and electric bridge
A closed control circuit is formed, when gas concentration is zero, arm resistance is adjusted, electric bridge is made to be in equilibrium state；When to be checked
When survey gas passes through sensor, causes sensor temperature to change, and then resistance of sensor is made to change, electric bridge is made to lose
Balance, the unbalance voltage of output is amplified to be sent to control servo circuit, and then controlling current source change output current value will
The resistance value of sensor reverts to original state again, can by detecting bridge arm voltage to restore electric bridge to equilibrium state
To detect tested gas concentration value.Sensor temperature in traditional detection method is thus overcome with tested gas concentration to change
Caused defect.But the program needs acquisition unbalance voltage in real time, and uses variable current source, while also needing to specially set
The size of current of control circuit control current source output is set, this structure is relatively complicated, final effect heavy dependence
In the precision of harvester and control device, cost is higher.
Utility model content
The purpose of this utility model is to provide a kind of self-regulation thermal conductivity gas sensor to solve current heat-conducted gas
The problem of sensor structure complexity.Also provide a kind of gas-detecting device of the application sensor simultaneously.
The utility model is in order to solve the above technical problems, provide scheme one：A kind of self-regulating heat conduction of the utility model
Gas sensor, the sensor include thermistor, first resistor, second resistance, 3rd resistor, the first operational amplifier and
The in-phase input end of two operational amplifiers, first operational amplifier and second operational amplifier is grounded, first operation amplifier
The inverting input of device connects its output end by 3rd resistor, and the inverting input of the second operational amplifier passes through the first electricity
Resistance connects its output end, and the inverting input of first operational amplifier connects the second operational amplifier by second resistance
Output end, the output end of first operational amplifier connect the anti-phase output of the second operational amplifier by the thermistor
End.
This programme, when operational amplifier circuit is stablized, makes heat by the way that the thermistor of sensor to be placed in two stage amplifer circuit
Quick resistance can keep the operating temperature and operating resistance of setting, and when being passed through tested gas, temperature-sensitive electricity will be changed by being tested gas
The operating temperature of resistance, to change the resistance value of temperature sensing module, but the temperature sensing module can be by operational amplifier circuit certainly
Regulatory function and reach fixed resistance value size, when entire circuit again restore stablize when, the temperature and resistance value weight of thermistor
It newly is restored to setting value, the voltage value exported at this time according to operational amplifier circuit can reflect the thermal conductivity for being passed through gas, and then obtain
To the concentration value for being passed through gas.Since thermistor keeps identical resistance value afterwards before detection, the temperature drift of itself is avoided
It moves, improves the precision of measurement.This programme does not include Current Voltage harvester, and control circuit, therefore structure need not be arranged
Simply, of low cost, while also achieving the automatic regulation function to thermistor resistance value size.
Scheme two：On the basis of scheme one, which is platinum resistance or thermocouple.
Scheme three：A kind of self-regulating heat conduction gas-detecting device of the utility model, including shell and detection therein
Gas circuit further includes to the self-regulation thermal conductivity gas sensor that gas is detected in detection gas circuit, and shell is equipped with air inlet
With gas outlet, pass through the detection gas circuit unicom between air inlet and gas outlet；The self-regulation thermal conductivity gas sensor includes heat
Quick resistance, first resistor, second resistance, 3rd resistor, the first operational amplifier and second operational amplifier, first operation are put
The in-phase input end ground connection of big device and second operational amplifier, the inverting input of first operational amplifier pass through 3rd resistor
Its output end is connected, the inverting input of the second operational amplifier connects its output end by first resistor, first operation
The inverting input of amplifier connects the output end of the second operational amplifier by second resistance, first operational amplifier
Output end connects the reversed-phase output of the second operational amplifier by the thermistor.
This programme has used a kind of measurement sensor of can be self-regulated temperature-sensitive resistance performance temperature and resistance value, existing to reduce
Have that gas-detecting device is complicated of high cost in technology and can not achieve the defect of self-regulation.The thermistor of the sensor is set
In two stage amplifer circuit, when operational amplifier circuit is stablized, thermistor is enable to keep the operating temperature and operating resistance of setting,
When being passed through tested gas, tested gas will change the operating temperature of thermistor, to change the resistance value of temperature sensing module,
But the temperature sensing module can reach fixed resistance value size by operational amplifier circuit self-regulating function, when entire circuit weight
When new recovery is stablized, the temperature and resistance value of thermistor are restored to setting value, the voltage exported at this time according to operational amplifier circuit
Value, can reflect the thermal conductivity for being passed through gas, and then obtain the concentration value for being passed through gas.Due to thermistor before detection after
Identical resistance value is kept, the temperature drift of itself is avoided, improves the precision of measurement.This programme is adopted not comprising Current Voltage
Control circuit need not be arranged in acquisition means, therefore simple in structure, of low cost, while also achieving big to thermistor resistance value
Small automatic regulation function.
Scheme four：On the basis of scheme three, which is platinum resistance or thermocouple.
Scheme five：On the basis of scheme three or four, which further includes thermostat module and for regulating and controlling thermostat module temperature
The temperature control module of degree, the thermostat module are the heat-conducting block with groove structure or through-hole structure, which is placed in the constant temperature
In the groove structure or through-hole structure of module.
This programme in gas-detecting device be provided with constant temperature heat-conducting block, and by detect gas circuit be placed in heat-conducting block inside or
Surface, the temperature for the tested gas heating and thermal insulation in gas circuit, making tested gas be kept constant in detection process.Due to
The thermal conductivity coefficient of tested gas at different temperatures is different, and the temperature of tested gas is maintained at a steady state value, avoided by this programme
Because of error caused by tested gas temperature difference when detection, the measurement accuracy of gas-detecting device is improved.
Scheme six：On the basis of scheme five, which further includes for receiving processing self-regulating heat conduction gas sensing
The signal processing module of device signal, the signal processing module are placed in inside or around the thermostat module.
Signal processing module is arranged inside or around thermostat module this programme, and signal processing module is made to keep constant
Operating temperature, avoid the temperature drift errors brought because signal processing module operating temperature is different, ensure that gas is examined
Survey the measurement accuracy of device.
Scheme seven：On the basis of scheme six, which includes temperature sensing unit, thermostat unit and calculating
Processing unit, the temperature sensing unit are placed in inside or around the thermostat module, the temperature sensing unit and the calculation processing
Unit sampling connects, which connects with calculation processing unit control.
Scheme eight：On the basis of scheme five, which is U-shaped groove or the through-hole structure is U-shaped through-hole.
This programme uses the groove or through-hole of U-shaped, can facilitate the setting of gas circuit air inlet gas outlet, and simplify entire dress
The volume set.
Scheme nine：On the basis of scheme seven, the thermostat unit be semiconductor temperature block, heating plate, heating film or
Resistance wire.
Description of the drawings
Fig. 1 is the structural schematic diagram of the utility model gas-detecting device embodiment one；
Wherein, 1 is shell, and 2 be semiconductor temperature block, and 3 be temperature sensor, and 4 be air inlet, and 5 be gas outlet, and 6 be perseverance
Wen Chi, 7 be measurement sensor, and 8 be signal-processing board, and 9 be detection gas circuit；
Fig. 2 is the circuit diagram of the utility model self-regulation thermal conductivity gas sensor.
Specific implementation mode
The utility model is described in further details with embodiment with reference to the accompanying drawings of the specification.
As Fig. 1 be a kind of a kind of embodiment of self-regulating heat conduction gas-detecting device, the device include shell and its
In detection gas circuit, signal processing module (such as signal-processing board), air inlet pipeline and outlet pipe, air inlet pipeline and escape pipe
Road connects and composes detection gas circuit, further includes to the self-regulation thermal conductivity gas sensor that gas is detected in detection gas circuit, really
Protect the sensor sensing element (such as thermistor) can touch tested gas (such as by sensing element setting detecting
In gas circuit or setting be connected to detection gas circuit for placing the chamber of sensing element), or ensure that the sensing element contacts and examine
It surveys gas circuit tube wall and gas temperature is tested with indirect acquisition；Shell is equipped with air inlet and gas outlet, between air inlet and gas outlet
Pass through the detection gas circuit unicom；The self-regulation thermal conductivity gas sensor includes thermistor Rm, which passes through this
Measurement sensor connect the outlet pipe constitute detection gas circuit, the device further include for provide the thermostat module of isoperibol and
Temperature control module for regulating and controlling thermostat module temperature, the temperature control module make the temperature of thermostat module for regulating and controlling thermostat module temperature
Degree is maintained at the steady temperature of setting.The thermostat module is the heat-conducting block with groove structure or through-hole structure, the detection gas
Road is placed in the groove structure or through-hole structure of the thermostat module, for making tested gas keep constant temperature in detection process
Degree, to avoid the measurement error caused by gas temperature difference；The signal processing module is also placed in inside thermostat module (certainly
Can be arranged the surface of thermostat module or around), the operating temperature for making signal processing module also keep constant, to avoid because
The temperature drift errors that its operating temperature is different and generates；The temperature control module includes the temperature of the temperature for detecting thermostat module
Sensing unit, for the thermostat unit (such as semiconductor temperature block) of regulating thermostatic module temperature and for receiving the temperature
It spends the temperature feedback of sensor and sends out the calculation processing module (such as processor) that temperature control instructs to the temperature-regulating module.
Measurement sensor circuit diagram is as shown in Fig. 2, include thermistor Rm, the first operational amplifier A and second fortune
Calculate amplifier B, the in-phase input end ground connection of first operational amplifier A and second operational amplifier B, first operational amplifier
The inverting input of A connects its output end by 3rd resistor R3, and the inverting input of second operational amplifier B passes through first
Resistance R1 connects its output end, and the inverting input of first operational amplifier A connects second operation by second resistance R2
The output end of the output end of amplifier B, first operational amplifier A passes through thermistor RmConnect second operational amplifier B
Reversed-phase output.
The physical circuit of measurement sensor uses the positive feedback system constant gain of amplifier for 1 and sensor measurement resistance
Temperature-sensitive is specific, and the temperature of measurement resistance is made to keep constant.Wherein R1, R2, R3 are fixed value resistance, RmIt is the temperature-sensitive of positive temperature coefficient
The measurement resistance of resistance and sensor, ImTo flow through RmElectric current, U1For 1 foot voltage of amplifier, UoFor 7 foot voltage of amplifier,
It can be used as output signal.
So, following equalities can be obtained according to circuit analysis：
It is obtained by (1) (2)：
It can be obtained from formula (3), R when amplifier balancesmResistance value also be definite value (definite value is related with the resistance value of R1, R2, R3, can
To be manually set by adjusting).Due to RmSensitive characteristic, R when resistance value is constantmTemperature also be definite value.It successfully realizes and keeps away at this time
The temperature drift of sensor of semiconductor structure itself is exempted from.
While satisfaction avoids error source, it is often more important that output signal UoWith tested heat conductivity of gas at certain
Proportionate relationship.
1st kind of situation, as the pyroconductivity λ increases of gas, thermistor RmTemperature TmIt reduces, the resistance value of thermistor
RmIt reduces, the electric current I in operational amplifier circuit self-regulation formula (1)mIncrease, the T of thermistormIncrease, the resistance value R of thermistormWeight
The new resistance value for increasing to setting, makes circuit reach balance again.Pass through the U exported at this timeoIt can be obtained by the heat of tested gas
Conductance, and then obtain the concentration of gas.
2nd kind of situation, as the pyroconductivity λ reductions of gas, the temperature T of thermistormIncrease, the resistance value R of thermistorm
Increase, the electric current I in operational amplifier circuit self-regulation formula (1)mIt reduces, the T of thermistormIt reduces, the resistance value R of thermistormAgain
It is reduced to the resistance value of setting, circuit is made to reach balance again.
Find out from both the above situation formula, thermal conductivity λ and ImAt certain proportionate relationship.There is U againo=-ImR1, so Uo
With thermal conductivity λ also at certain proportionate relationship.So passing through the output U of circuit when measurement rebalancingoIt can be obtained by tested
The thermal conductivity of gas, and then obtain the concentration of gas.
In above-described embodiment, it includes thermoelectricity to have used sensing element of the thermistor as measurement sensor, thermistor
Occasionally platinum resistance.
In above-described embodiment, air inlet pipeline, measurement sensor and outlet pipe are formed into detection gas circuit, and in constant temperature heat conduction
U-shaped groove or through-hole of the setting for placing detection gas circuit on block, it is of course possible to by the groove and lead in specific implementation
Hole is shaped to linear, L-shaped or other shapes convenient to carry out.
It has used semiconductor temperature block as the thermostat unit of thermostat module in above-described embodiment, heating also can be used
Piece, heating film or resistance wire are as other embodiments.
Specific embodiment is presented above, but the utility model is not limited to described embodiment.This practicality
Novel basic ideas are above-mentioned basic scheme, in the case where not departing from the principles of the present invention and spirit to embodiment party
The change, modification, replacement and modification that formula carries out are still fallen in the scope of protection of the utility model.
Claims (9)
1. a kind of self-regulation thermal conductivity gas sensor, it is characterised in that：The sensor includes thermistor, first resistor,
Two resistance, 3rd resistor, the first operational amplifier and second operational amplifier, first operational amplifier and the second operation are put
The in-phase input end ground connection of big device, the inverting input of first operational amplifier connect its output end by 3rd resistor,
The inverting input of the second operational amplifier connects its output end by first resistor, first operational amplifier it is anti-
Phase input terminal connects the output end of the second operational amplifier, the output end of first operational amplifier by second resistance
The reversed-phase output of the second operational amplifier is connected by the thermistor.
2. self-regulation thermal conductivity gas sensor according to claim 1, it is characterised in that：The thermistor is platinum electricity
Resistance or thermocouple.
3. a kind of self-regulating heat conduction gas-detecting device, including shell and detection gas circuit therein further include to detecting gas circuit
The self-regulation thermal conductivity gas sensor that middle gas is detected, shell are equipped with air inlet and gas outlet, air inlet and outlet
Pass through the detection gas circuit unicom between mouthful；It is characterized in that：The self-regulation thermal conductivity gas sensor include thermistor,
First resistor, second resistance, 3rd resistor, the first operational amplifier and second operational amplifier, first operational amplifier
It is grounded with the in-phase input end of second operational amplifier, the inverting input of first operational amplifier is connected by 3rd resistor
Its output end is connect, the inverting input of the second operational amplifier connects its output end, first fortune by first resistor
The inverting input for calculating amplifier connects the output end of the second operational amplifier by second resistance, and first operation is put
The output end of big device connects the reversed-phase output of the second operational amplifier by the thermistor.
4. self-regulating heat conduction gas-detecting device according to claim 3, it is characterised in that：The thermistor is platinum
Resistance or thermocouple.
5. self-regulating heat conduction gas-detecting device according to claim 3 or 4, it is characterised in that：The device further includes
Thermostat module and temperature control module for regulating and controlling the thermostat module temperature, the thermostat module are with groove structure or through-hole
The heat-conducting block of structure, the detection gas circuit are placed in the groove structure or through-hole structure of the thermostat module.
6. self-regulating heat conduction gas-detecting device according to claim 5, it is characterised in that：The device further includes being used for
The signal processing module for handling the self-regulating heat conduction gas sensor signal is received, the signal processing module is placed in described
Inside or around thermostat module.
7. self-regulating heat conduction gas-detecting device according to claim 6, it is characterised in that：The temperature control module includes
Temperature sensing unit, thermostat unit and calculation processing unit, the temperature sensing unit are placed in the interior of the thermostat module
Portion or surrounding, the temperature sensing unit are connected with calculation processing unit sampling, the thermostat unit and the meter
Calculate processing unit control connection.
8. self-regulating heat conduction gas-detecting device according to claim 5, it is characterised in that：The groove structure is U
Connected in star or the through-hole structure are U-shaped through-hole.
9. self-regulating heat conduction gas-detecting device according to claim 7, it is characterised in that：The thermostat unit
For semiconductor temperature block, heating plate, heating film or resistance wire.
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201721907109.9U CN207675682U (en) | 2017-12-30 | 2017-12-30 | Be self-regulated thermal conductivity gas sensor and gas-detecting device |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201721907109.9U CN207675682U (en) | 2017-12-30 | 2017-12-30 | Be self-regulated thermal conductivity gas sensor and gas-detecting device |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN109991265A (en) * | 2017-12-30 | 2019-07-09 | 光力科技股份有限公司 | A kind of self-regulation thermal conductivity gas sensor and gas-detecting device |
| CN113588710A (en) * | 2021-09-29 | 2021-11-02 | 武汉祺璞科技有限公司 | Component concentration detection device and method for mixed gas and application |
-
2017
- 2017-12-30 CN CN201721907109.9U patent/CN207675682U/en active Active
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN109991265A (en) * | 2017-12-30 | 2019-07-09 | 光力科技股份有限公司 | A kind of self-regulation thermal conductivity gas sensor and gas-detecting device |
| CN113588710A (en) * | 2021-09-29 | 2021-11-02 | 武汉祺璞科技有限公司 | Component concentration detection device and method for mixed gas and application |
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