CN114384951B - Constant temperature system for conductivity detector and control method - Google Patents

Constant temperature system for conductivity detector and control method Download PDF

Info

Publication number
CN114384951B
CN114384951B CN202111529861.5A CN202111529861A CN114384951B CN 114384951 B CN114384951 B CN 114384951B CN 202111529861 A CN202111529861 A CN 202111529861A CN 114384951 B CN114384951 B CN 114384951B
Authority
CN
China
Prior art keywords
heating
temperature
module
triode
heat
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Active
Application number
CN202111529861.5A
Other languages
Chinese (zh)
Other versions
CN114384951A (en
Inventor
明中平
方政
孙红
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Anhui Wanyi Science and Technology Co Ltd
Original Assignee
Anhui Wanyi Science and Technology Co Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Anhui Wanyi Science and Technology Co Ltd filed Critical Anhui Wanyi Science and Technology Co Ltd
Priority to CN202111529861.5A priority Critical patent/CN114384951B/en
Publication of CN114384951A publication Critical patent/CN114384951A/en
Application granted granted Critical
Publication of CN114384951B publication Critical patent/CN114384951B/en
Active legal-status Critical Current
Anticipated expiration legal-status Critical

Links

Images

Classifications

    • G—PHYSICS
    • G05—CONTROLLING; REGULATING
    • G05D—SYSTEMS FOR CONTROLLING OR REGULATING NON-ELECTRIC VARIABLES
    • G05D23/00—Control of temperature
    • G05D23/19—Control of temperature characterised by the use of electric means
    • G05D23/30—Automatic controllers with an auxiliary heating device affecting the sensing element, e.g. for anticipating change of temperature
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N30/00—Investigating or analysing materials by separation into components using adsorption, absorption or similar phenomena or using ion-exchange, e.g. chromatography or field flow fractionation
    • G01N30/02—Column chromatography
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N30/00—Investigating or analysing materials by separation into components using adsorption, absorption or similar phenomena or using ion-exchange, e.g. chromatography or field flow fractionation
    • G01N30/02—Column chromatography
    • G01N30/62—Detectors specially adapted therefor
    • G01N30/64—Electrical detectors
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N30/00—Investigating or analysing materials by separation into components using adsorption, absorption or similar phenomena or using ion-exchange, e.g. chromatography or field flow fractionation
    • G01N30/02—Column chromatography
    • G01N30/62—Detectors specially adapted therefor
    • G01N30/64—Electrical detectors
    • G01N2030/645—Electrical detectors electrical conductivity detectors

Landscapes

  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • General Health & Medical Sciences (AREA)
  • Chemical & Material Sciences (AREA)
  • Analytical Chemistry (AREA)
  • Biochemistry (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Health & Medical Sciences (AREA)
  • Immunology (AREA)
  • Pathology (AREA)
  • Engineering & Computer Science (AREA)
  • Automation & Control Theory (AREA)
  • Control Of Temperature (AREA)

Abstract

The invention discloses a constant temperature system for a conductivity detector and a control method, belonging to the technical field of environmental protection monitoring. The invention uses the single chip to control the output voltage of the digital-to-analog converter to adjust the power, eliminates the switching noise generated during the traditional heating control, reasonably utilizes the heating defect of the heating triode, reduces the heat loss caused by the traditional wire harness connection by welding the heating triode on the circuit board, improves the stability of the integral reference by sharing the collector electrode of the heating triode, the radiating pad of the triode and the heat conducting module, respectively arranges the temperature collecting module on the heating point and the inner wall of the heat preservation shell, realizes the rapid heating and the accurate temperature control by the design of two-stage temperature detection, realizes the constant temperature in the whole heat preservation shell, and reduces the interference on the conductivity detector to the maximum extent.

Description

Constant temperature system for conductivity detector and control method
Technical Field
The invention relates to the technical field of environmental protection monitoring, in particular to a constant temperature system for a conductivity detector and a control method.
Background
An electrical conductivity detector (ELCD) is one of the components of an ion chromatograph, which is designed based on the theory of ion chromatography, which separates different ions by using the difference in affinity between ions for an ion exchange resin, that is, by using the difference in affinity between ions for an ion exchange resin. The conductivity detector is mainly used for detecting sulfur, halogen, nitride and other conductive compounds, and it decomposes the tested substance into hydride or oxide, ionizes in deionized solution, and detects the content of ionic component in the original solution according to the change of conductivity in the solution. In recent years, along with the miniaturization of detection instruments, the volume of a detection pool is reduced, the content of a sample to be detected is reduced, and the detection precision is continuously improved. Meanwhile, the conductivity detection has the advantages of rapidness, convenience, high sensitivity, good selectivity, capability of analyzing various ionic compounds simultaneously and the like, and becomes one of the main ion detection modes at present.
The development of the conductivity detector has three stages, a gas chromatography conductivity detection method is proposed for the first time in 1962, and the change of the conductivity of the hydrocarbon into carbon dioxide in deionized water is measured; it was improved in 1965 to detect halogen, sulfur and nitrogen compounds; a micro-conductor is proposed in 1974, so that the selectivity and the sensitivity are both obviously improved at present; with the continuous improvement of theory, a dipolar, a quadrapole and a pentapolar conductivity detector has appeared on the market at present according to the quantity of the detection polarity of the conductivity cell.
At present, the conductance detector is widely applied in the market, but the design of the conductance detector still has some defects, the accuracy of the conductance detector is poor, the adaptability to the environment is poor, the application range and the user experience of the conductance detector are seriously influenced, and the detection accuracy of the conductance detector can be greatly improved in a good constant-temperature environment. Therefore, a constant temperature system for a conductivity detector and a control method are provided.
Disclosure of Invention
The technical problem to be solved by the invention is as follows: how to solve the difficult problems of low temperature control precision and switching noise during temperature rise of the conventional conductivity detector, and provides a constant temperature system for the conductivity detector.
The invention solves the technical problems through the following technical scheme, and the electric conductivity detector comprises a control module, a driving module, a heating module, a heat conduction module, a temperature acquisition module and a heat preservation shell, wherein the control module is connected with the driving module, the heating module, the heat conduction module and the temperature acquisition module are arranged in the heat preservation shell, and the control module and the temperature acquisition module are connected with external power supply communication through wiring harnesses, so that the whole sealing performance of the electric conductivity detector is ensured to the maximum extent.
Furthermore, the control module, the driving module, the heating module and the temperature acquisition module are all arranged on a printed circuit board of the conductivity detector.
Furthermore, the control module comprises a digital-to-analog converter and a voltage stabilizing resistor, wherein the output end of the digital-to-analog converter is connected with the voltage stabilizing resistor, different output voltages are set through the digital-to-analog converter, and the heating power of the heating module is set.
Furthermore, the heating module comprises two heating triodes with the same specification, the collector electrodes of the triodes are directly connected with the heat dissipation welding disc, the heat dissipation welding disc is fixed on the heat conduction module, and heat energy generated by the heating triodes is transferred to the heat conduction module from the heat dissipation welding disc and then transferred to the printed circuit board.
Furthermore, the driving module comprises an operational amplifier, a driving triode and two sampling resistors, wherein the sampling resistors are arranged between an emitting electrode of the heating triode and a power supply end, a reverse input end of the operational amplifier is connected with the digital-to-analog converter through the voltage stabilizing resistor and used for voltage setting, meanwhile, the reverse input end and a forward input end are connected with any one sampling resistor to form a feedback loop, the closed-loop design of a circuit is realized, only one of the two sampling resistors is connected, the design symmetry is reasonably utilized, an output end is connected with a base electrode of the driving triode and used for controlling the conduction of the driving triode, and the emitting electrode is connected with base electrodes of the two heating triodes and used for controlling the conduction of the two heating triodes.
Furthermore, the collector of the heating triode, the collector of the driving triode, the power supply cathode of the operational amplifier, the heat dissipation pad and the heat conduction module are all connected with the ground, and the whole conductivity detector forms the same ground reference.
Furthermore, the temperature acquisition module is two platinum resistance temperature sensors, one of the two platinum resistance temperature sensors is embedded in the heat conduction module and is close to the heating triode radiating pad to acquire the temperature of a heat source, the other platinum resistance temperature sensor is embedded in the edge of the heat conduction module and is far away from the heating triode radiating pad to acquire the temperature of the edge of the module, and the temperature control precision is improved through the two platinum resistance temperature sensors.
Furthermore, the heat-insulating shell is made of high-density rubber and plastic cotton, so that the overall temperature balance of the conductivity detector is ensured.
Furthermore, the heating module and the heat conduction module are separated by heat insulation cotton, so that short circuit of the printed circuit board is prevented.
The invention also provides a constant temperature control method for the conductance detector, which utilizes the constant temperature control system to carry out constant temperature control on the conductance detector and comprises the following steps:
s1: the control module sets a specified temperature, the digital-to-analog converter outputs a set value voltage of 2V at the moment, the heating is carried out at the maximum power, the control module controls the driving module to turn on the driving triode, the driving triode is turned on to heat the triode, and the heating triode is heated;
s2: the temperature acquisition module acquires real-time temperature of a platinum resistor temperature sensor far away from a heating triode radiating pad and transmits the real-time temperature to the control module;
s3: and stopping heating when the set temperature is the same as the real-time temperature, and starting heating when the set temperature is lower than the real-time temperature.
Compared with the prior art, the invention has the following advantages: this constant temperature system for conductivity detector, with single chip microcomputer control digital analog converter output voltage regulated power, the switching noise that produces when having eliminated traditional heating control, the shortcoming of generating heat of rational utilization heating triode, through heating the triode welding on the circuit board, the heat loss that traditional pencil connection brought has been reduced, heating triode collecting electrode, triode radiating pad, heat conduction module is altogether, the stability of wholly referring to has been improved, respectively place the temperature acquisition module at heating point and heat preservation casing inner wall, doublestage temperature detection's design, both realized the rapid heating, again can accurate accuse temperature, make the realization in the whole heat preservation casing constant temperature, furthest's reduction is to the interference of conductivity detector, be worth using widely.
Drawings
FIG. 1 is a schematic structural diagram of a thermostat system in an embodiment of the invention;
fig. 2 is a schematic view of the heating control principle of the constant temperature system in the embodiment of the invention.
Detailed Description
The following examples are given for the detailed implementation and specific operation of the present invention, but the scope of the present invention is not limited to the following examples.
As shown in fig. 1 and 2, the present embodiment provides a technical solution: a conductance detector thermostat system, comprising: the temperature-keeping device comprises a heat-keeping shell 1, a printed circuit board 2, a heat-conducting aluminum block 3 (namely, a heat-conducting module provided by the invention), temperature sensors 4 and 5, heating triodes 6 and 7 (MJE 2955) (namely, a heating module provided by the invention), fixing screws 8 and 9, a digital-to-analog converter 10 (DAC 8801), a resistor 11 (100K omega), a resistor 12 (6.81K omega), a resistor 13 (6.81K omega), a resistor 14 (107K omega), a capacitor 15 (100 pF), an operational amplifier 16 (OPA 2197), a resistor 17 (10K omega), a driving triode 18 (MJE 172), sampling resistors 19 and 20 (10 omega), 24V 21, 22 and 23, and grounding points 24, 25, 26 and 27.
In this embodiment, printed circuit board 2, heat conduction aluminium pig 3, temperature sensor 4, 5, heating triode 6, 7, set screw 8, 9 all set up in the inside of heat preservation casing 1, printed circuit board 2 and heat conduction aluminium pig are separated by the cotton that keeps warm between 3, heating triode 6, six pins altogether of 7 are fixed on printed circuit board 2, set screw 8, 9 will heat the heat dissipation pad of triode and fix on heat conduction aluminium pig 3, temperature sensor 5 fixes in being close to near the slotted hole that heats triode 6, temperature sensor 6 fixes in the slotted hole between heat conduction aluminium pig 3 and heat preservation casing 1, printed circuit board 2 and heat conduction aluminium pig 3 are hugged closely to heat preservation casing 1, prevent that whole conductivity detector from appearing rocking.
In the present embodiment, the digital-to-analog converter 10 (DAC 8801), the resistor 11 (100K Ω), the resistor 12 (6.81K Ω), the resistor 13 (6.81K Ω), the resistor 14 (107K Ω), the capacitor 15 (100 pF), the operational amplifier 16 (AD 822A), the resistor 17 (10K Ω), the driving transistor 18 (MJE 172), the heating transistors 6 and 7 (MJE 2955), the sampling resistors 19 and 20 (10 Ω), the 24V power terminals 21 and 22 and 23, and the ground points 24, 25, 26 and 27 are components of the printed circuit board 2, and are integrated with the printed circuit board 2 (the printed circuit board 2 is a circuit board of the conductance detector).
In this embodiment, the digital-to-analog converter 10, the resistor 11 and the temperature control software together form a control module, the digital-to-analog converter 10 (DAC 8801) can set the voltage range to 0-2V, and the output voltage is set
Figure GDA0004003930130000041
Figure GDA0004003930130000042
Wherein D is a set value, V REF The voltage setting accuracy is 0.00012V with =2V as a reference voltage, and the resistor 11 is used to stably set the voltage.
In this embodiment, the resistor 12, the resistor 13, the resistor 14, the capacitor 15, the operational amplifier 16, the resistor 17, the driving transistor 18 (PNP type), the sampling resistors 19 to 20, the 24V power supply terminals 21 to 23, and the grounding points 24 to 26 together form a driving module, and the driving transistor 18 supplies necessary current to the bases of the heating transistors 6 and 7, so as to drive the heating transistors 6 and 7 to be turned on.
In this embodiment, the divided voltage value of the resistor 13 and the resistor 14 is used as the comparison value of the voltage setting (when the resistor 13 is R1, the resistor 14 is R2, and the 24V power source terminal is VCC, the voltage comparison value is
Figure GDA0004003930130000043
)。
In the present embodiment, the resistor 12 is used for compensating the input resistor of the operational amplifier 16, and the capacitor 15 is used for implementing pre-compensation of the operational amplifier 16, so as to prevent the operational amplifier 16 from generating output oscillation.
In this embodiment, the resistor 17 is used to implement the base current limiting of the driving transistor 18, so as to protect the driving transistor 18.
In this embodiment, the heating process is as follows:
1. in an initial state, the digital-to-analog converter 10 is not set with voltage, the operational amplifier 16 amplifies the output voltage in an open loop mode to be 24V, and the driving triode 18 and the heating triodes 6 and 7 are not conducted and are not heated;
2. in the heating state, the digital-to-analog converter 10 performs voltage setting, the default setting value is 2V when heating is started, maximum power heating is performed, when the set temperature is reached, the voltage setting value is correspondingly reduced according to a PID algorithm, the open-loop amplification output voltage of the operational amplifier 16 is 0V, the triode 18 and the heating triodes 6 and 7 are driven to be conducted, heating is started, the digital-to-analog converter 10 is adjusted to output different voltage values, and therefore voltages at two ends of the sampling resistor are changed, and heating power is set.
In this embodiment, the heating is performedThe rated power of the triodes 6 and 7 is 2W, the heating power is determined by the resistance values of the sampling resistors 19 and 20, the current flowing through the heating triodes 6 and 7 is the same as the current flowing through the sampling resistors 19 to 20, the rated power of the sampling resistor is 2W, the voltage range of the digital-to-analog converter 10 is set to be 0V to 2V, the voltage difference between two ends of the sampling resistor is 0V to 2V according to the voltage division ratio of the resistor 11, the resistor 12 and the sampling resistor 19, and the ohm's law is adopted
Figure GDA0004003930130000051
I is current, U is voltage, R is resistance, the current on the sampling resistor 19 can be set to be 0A-0.2A, the voltage at both ends of the collector and emitter of the heating triode is 22V-24V, i.e. the differential pressure between both ends of the collector and emitter of the heating triode is 0V-2V, according to the power calculation formula P = U × I, P is current, U is voltage, I is resistance, the power range of a single heating triode is 0W-0.4W, according to the symmetry design of the heating triode, the state of the heating triode 7 is also reflected on the heating triode 6, so that the voltage range of the digital-to-analog converter 10 is set to be 0V-2V, and the corresponding total heating power range is 0W-0.8W.
In this embodiment, the temperature sensors 4 and 5 constitute a temperature acquisition module, the temperature sensor is a platinum resistor temperature sensor, and when the temperature range is 0-600 ℃, the resistance value R of the platinum resistor is T ＝R 0 ×(1+A×T+B×T 2 )，R 0 Is the resistance value of the platinum resistor at 0 ℃, A =3.9083 × 10 -3 ℃ -1 ，B＝-5.775×10 -7 ℃ -2 And T is the real-time temperature, and the real-time temperature is deduced according to the change of the resistance value of the platinum resistor. Two platinum resistance temperature sensors (temperature sensor 4, 5) monitor the real-time temperature of cavity edge and heating point respectively, the temperature of cavity edge monitoring point (temperature sensor 4) is the target temperature, the detection of the real-time temperature of heating point (temperature sensor 5) is to prevent the heating point from causing naked light due to overhigh temperature, cause the damage of conductance detector, when setting a target temperature, form a closed-loop design with the heating module through this temperature acquisition module, the temperature sensor 5 at edge is used for monitoring the average temperature of the whole conductance detector, realize accurate temperature control, the temperature setting precision can reach 0.1 ℃.
In this embodiment, the temperature control is adjusted by software PID, a target temperature is set, the temperature sensor 4 collects a real-time temperature, and the magnitude of the set voltage of the digital-to-analog converter is determined according to a difference between the real-time temperature and the target temperature.
Figure GDA0004003930130000061
This equation represents the temperature value P at time t error (t) a calculation method in which kp, ki and kd respectively represent proportional, integral and differential coefficients, error is the difference between a set value and a measured value,
Figure GDA0004003930130000062
for each control error accumulated value, error (t) is an error value at the current moment, and error (t-1) is an error value at the previous moment.
To sum up, the conductance detector constant temperature system of the above embodiment, structural design is simple, the miniaturization of the conductance detector is reflected, the space is effectively utilized, the heating stability is good, the single chip microcomputer is used for controlling the output voltage of the digital-to-analog converter to adjust the power, the switching noise generated during the traditional heating control is eliminated, the heating defect of the heating triode is reasonably utilized, the heating triode is welded on the circuit board, the heat loss caused by the traditional wire harness connection is reduced, the collector electrode of the heating triode, the triode radiating pad and the heat conducting module are grounded, the stability of the overall reference is improved, the temperature collecting module is respectively arranged on the heating point and the inner wall of the heat preservation shell, and the design of two-stage temperature detection not only realizes the rapid heating, but also can accurately control the temperature, so that the constant temperature in the whole heat preservation shell is realized, the interference to the conductance detector is reduced to the greatest extent, and the conductance detector is worthy of popularization and use.
Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention, and that variations, modifications, substitutions and alterations can be made to the above embodiments by those of ordinary skill in the art within the scope of the present invention.

Claims (6)

1. A constant temperature system for a conductivity detector is characterized by comprising a control module, a driving module, a heating module, a heat conduction module, a temperature acquisition module and a heat preservation shell, wherein the control module is connected with the driving module;
the control module comprises a digital-to-analog converter and a voltage stabilizing resistor, wherein the output end of the digital-to-analog converter is connected with the voltage stabilizing resistor, different output voltages are set through the digital-to-analog converter, and the heating power of the heating module is set;
the heating module comprises two heating triodes with the same specification, the collector electrodes of the triodes are directly connected with a heat dissipation welding disc, the heat dissipation welding disc is fixed on the heat conduction module, and heat energy generated by the heating triodes is transferred to the heat conduction module from the heat dissipation welding disc and then transferred to the printed circuit board;
the driving module comprises an operational amplifier, a driving triode and two sampling resistors, wherein the sampling resistors are arranged between an emitting electrode and a power supply end of the heating triode, a reverse input end of the operational amplifier is connected with the digital-to-analog converter through the voltage stabilizing resistor, meanwhile, the reverse input end and a forward input end are connected with any one sampling resistor to form a feedback loop, an output end is connected with a base electrode of the driving triode, and the emitting electrode is connected with base electrodes of the two heating triodes;
the temperature acquisition module is composed of two platinum resistance temperature sensors, one of the two platinum resistance temperature sensors is embedded in the heat conduction module and close to the heating triode radiating pad to acquire the temperature of a heat source, the other platinum resistance temperature sensor is embedded at the edge of the heat conduction module and far away from the heating triode radiating pad to acquire the temperature of the edge of the module, and the temperature control precision is improved through the two platinum resistance temperature sensors;
the control module adopts software PID adjustment to control temperature, sets target temperature, a platinum resistor temperature sensor embedded at the edge of the heat conduction module collects real-time temperature, and the magnitude of the set voltage of the digital-to-analog converter is determined according to the difference value of the real-time temperature and the target temperature.
2. The thermostat system for a conductivity detector according to claim 1, wherein: the control module, the driving module, the heating module and the temperature acquisition module are all arranged on a printed circuit board of the conductivity detector.
3. The thermostat system for a conductivity detector according to claim 2, wherein: the collector electrode of the heating triode, the collector electrode of the driving triode, the power supply negative electrode of the operational amplifier, the heat dissipation pad and the heat conduction module are all connected with the ground.
4. The thermostat system for a conductivity detector according to claim 1, wherein: the heat-insulating shell is made of high-density rubber and plastic cotton.
5. The thermostat system for a conductivity detector according to claim 4, wherein: the heating module and the heat conduction module are separated by heat insulation cotton.
6. A thermostat control method for a conductance detector, characterized in that the conductance detector is thermostatically controlled by the thermostat control system according to claim 5, comprising the steps of:
s1: the control module sets a specified temperature, the digital-to-analog converter outputs a set value voltage of 2V at the moment, the heating is carried out at the maximum power, the control module controls the driving module to turn on the driving triode, the driving triode is turned on to heat the triode, and the heating triode is heated;
s2: the temperature acquisition module acquires real-time temperature of a platinum resistor temperature sensor far away from a heating triode radiating pad and transmits the real-time temperature to the control module;
s3: and stopping heating when the set temperature is the same as the real-time temperature, and starting heating when the set temperature is lower than the real-time temperature.
CN202111529861.5A 2021-12-14 2021-12-14 Constant temperature system for conductivity detector and control method Active CN114384951B (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CN202111529861.5A CN114384951B (en) 2021-12-14 2021-12-14 Constant temperature system for conductivity detector and control method

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CN202111529861.5A CN114384951B (en) 2021-12-14 2021-12-14 Constant temperature system for conductivity detector and control method

Publications (2)

Publication Number Publication Date
CN114384951A CN114384951A (en) 2022-04-22
CN114384951B true CN114384951B (en) 2023-04-07

Family

ID=81195289

Family Applications (1)

Application Number Title Priority Date Filing Date
CN202111529861.5A Active CN114384951B (en) 2021-12-14 2021-12-14 Constant temperature system for conductivity detector and control method

Country Status (1)

Country Link
CN (1) CN114384951B (en)

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN2638119Y (en) * 2003-06-18 2004-09-01 吴琪君 Constant temperature source chip
CN103176489A (en) * 2013-02-06 2013-06-26 南京千韵电子科技有限公司 Method and device for controlling chip inner temperature and experiment instrument based on same method
CN209044398U (en) * 2018-12-03 2019-06-28 中山市德斯科电子科技有限公司 A kind of modular circuit applied to thermostat heating

Family Cites Families (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN202929500U (en) * 2012-07-04 2013-05-08 航天科工惯性技术有限公司 Accelerometer and its temperature control circuit
CN202794126U (en) * 2012-07-29 2013-03-13 安徽皖仪科技股份有限公司 Conductance cell with solution temperature pretreatment function
CN205265930U (en) * 2015-12-29 2016-05-25 北京创新纪技术开发有限公司 High sensitivity electron temperature control system

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN2638119Y (en) * 2003-06-18 2004-09-01 吴琪君 Constant temperature source chip
CN103176489A (en) * 2013-02-06 2013-06-26 南京千韵电子科技有限公司 Method and device for controlling chip inner temperature and experiment instrument based on same method
CN209044398U (en) * 2018-12-03 2019-06-28 中山市德斯科电子科技有限公司 A kind of modular circuit applied to thermostat heating

Also Published As

Publication number Publication date
CN114384951A (en) 2022-04-22

Similar Documents

Publication Publication Date Title
US4911357A (en) Humidity controller utilizing absolute humidity
JP4692026B2 (en) Gas sensor
KR0183398B1 (en) Method and apparatus for the measurment of the thermal conductivity of gases
TW200903207A (en) Temperature control apparatus, processing apparatus, and temperature control method
US7028530B2 (en) Gas detector
JP4796756B2 (en) Measuring device for monitoring residual oxygen in exhaust gas and method for operating the measuring device
CN211017736U (en) Current drive circuit and laser wavelength control circuit
CN114384951B (en) Constant temperature system for conductivity detector and control method
CN109375675B (en) Constant temperature controller for assisting field equipment to operate in severe cold area
CN104897966A (en) Detecting system of zero resistance value of platinum resistor of nitrogen-oxygen sensor chip and method
CN110133061B (en) High-temperature sample table suitable for testing dielectric property of material
CN215895326U (en) Nitrogen oxygen sensor heating device and nitrogen oxygen sensor
CN215679166U (en) Constant current source feedback circuit, multi-channel constant current source and constant current source board card
CN115390599A (en) Multi-point temperature control system applied to standard photoelectric pyrometer
JPH07113777A (en) Atmosphere detecting device
JP2003156563A (en) Dark current compensation type ion chamber current measuring device
CN111045466A (en) Laser working temperature control circuit and control method thereof
CN211015176U (en) Laser working temperature control circuit
CN218470761U (en) Temperature control circuit, environmental wind information measuring device and system
EP1693669A2 (en) Device for measuring concentrations of carbon dioxide and oxygen
CN213416895U (en) Automatic temperature control device of culture dish
JPH0339717Y2 (en)
JP2000249683A (en) Gas-detecting apparatus
CN206021107U (en) Temperature control low-power consumption atomic pile
JP2008304272A (en) Gas concentration detector

Legal Events

Date Code Title Description
PB01 Publication
PB01 Publication
SE01 Entry into force of request for substantive examination
SE01 Entry into force of request for substantive examination
GR01 Patent grant
GR01 Patent grant