CN220340135U - Chromatograph heat conduction pool detection circuit - Google Patents
Chromatograph heat conduction pool detection circuit Download PDFInfo
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- CN220340135U CN220340135U CN202223447556.4U CN202223447556U CN220340135U CN 220340135 U CN220340135 U CN 220340135U CN 202223447556 U CN202223447556 U CN 202223447556U CN 220340135 U CN220340135 U CN 220340135U
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- 238000001514 detection method Methods 0.000 title claims abstract description 26
- 230000003750 conditioning effect Effects 0.000 claims abstract description 25
- 238000005070 sampling Methods 0.000 claims description 7
- 230000001143 conditioned effect Effects 0.000 claims description 5
- 230000009466 transformation Effects 0.000 claims description 3
- 238000004587 chromatography analysis Methods 0.000 claims description 2
- 230000003321 amplification Effects 0.000 claims 1
- 238000003199 nucleic acid amplification method Methods 0.000 claims 1
- 238000010586 diagram Methods 0.000 description 6
- 239000007789 gas Substances 0.000 description 2
- 230000001105 regulatory effect Effects 0.000 description 2
- 238000004458 analytical method Methods 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 239000012159 carrier gas Substances 0.000 description 1
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Abstract
The utility model belongs to the technical field of instruments and meters, and particularly relates to a chromatograph heat conduction pool detection circuit, which comprises: the device comprises a thermal conductivity cell constant current source circuit, a 24V front-stage power supply circuit, an external control reference voltage circuit, a thermal conductivity Chi Dianqiao circuit and a thermal conductivity cell signal conditioning circuit; the constant current source circuit of the heat conduction pool provides constant current power supply for the heat conduction pool; the 24V pre-stage voltage circuit provides a stable pre-stage power supply circuit for the constant current source; the external control reference voltage circuit can convert external reference voltage through impedance and is used for controlling the size of the constant current source; the heat conducting pool bridge circuit comprises a high-heat stable resistor and a heat conducting pool heat resistance, so as to form a corresponding bridge; the thermal conductivity cell signal conditioning circuit can condition, zero and amplify the thermal conductivity cell bridge signal and then output the thermal conductivity cell bridge signal to the corresponding voltage detection module. The utility model meets the requirements of power supply, signal conditioning and output of the chromatograph thermal conductivity cell detector.
Description
Technical Field
The utility model belongs to the technical field of instruments and meters, and particularly relates to a chromatograph heat conduction pool detection circuit.
Background
During gas chromatographic analysis, the components are detected in a detector after being separated by a chromatographic column, and corresponding signal output is realized according to the content change of the components; the detector is an important component of a gas chromatograph, since the signal generated and its magnitude are the basis for qualitative and quantitative components.
The Thermal Conductivity Detector (TCD) is a concentration type detector developed according to the difference of the composition and the thermal conductivity of the carrier gas. When the concentration of the sample component passes through the thermal conductivity cell and changes, different heat is taken away from the thermosensitive element, so that the resistance value of the thermosensitive element changes, and the change is measured by utilizing the bridge, so that a chromatographic outflow curve can be obtained, and the analysis of the sample component is realized.
The thermal conductivity detector generally satisfies: good stability, small baseline noise, small drift, small dead volume of the detector, quick response and the like.
The existing thermal conductivity cell detection circuit can not realize external control and circuit separation design of each module.
Disclosure of Invention
The utility model aims to provide a chromatograph heat conduction pool detection circuit which can meet the requirements of power supply, control, zero setting and detection of the chromatograph heat conduction pool and is suitable for the chromatograph with the heat conduction pool as a detector.
The technical scheme for realizing the purpose of the utility model comprises the following steps:
a chromatograph thermal conductivity cell detection circuit, the circuit comprising: the device comprises a thermal conductivity cell constant current source circuit, a 24V front-stage power supply circuit, an external control reference voltage circuit, a thermal conductivity Chi Dianqiao circuit and a thermal conductivity cell signal conditioning circuit; the output end of the 24V front-stage power supply circuit is connected with the input end of the heat conduction pool constant current source circuit, and a stable front-stage power supply circuit is provided for the heat conduction pool constant current source circuit; the output end of the external control reference voltage circuit is connected with the input end of the constant current source circuit of the thermal conductivity cell, and the external reference voltage is used for controlling the size of the constant current source through impedance transformation; the output end of the heat conduction pool constant current source circuit is connected with the input end of the heat conduction pool bridge circuit, and the heat conduction pool bridge circuit comprises a high-heat-stability resistor and a heat conduction pool thermal resistance to form a corresponding bridge; the output end of the heat conducting pool bridge circuit is connected with the input end of the heat conducting pool signal conditioning circuit, and signals of the heat conducting pool bridge circuit are conditioned, zeroed and amplified and then output to the corresponding voltage detection module.
The thermal conductivity cell constant current source circuit comprises a first impedance matching circuit and a voltage amplifying circuit; the first impedance matching circuit comprises an operational amplifier U 1 And a resistor connected with the external control reference voltage V in Connected, operational amplifier U 1 The output end is connected with the voltage amplifying circuit.
The voltage amplifying circuit comprises an operational amplifier U 2 And an amplifying ratio control resistor, an operational amplifier U 2 Output end and current output power triode Q 1 The base is connected.
The voltage amplifying circuit comprises a current output power triode Q 1 Current output power triode Q 1 The collector is connected with a 24V pre-stage power supply circuit, and the emitter is connected with a thermal conductivity cell bridge circuit.
The 24V pre-stage power supply circuit comprises a reference voltage chip U 3 The second impedance matching circuit and the adjustment comparison circuit; reference voltage chip U 3 The input end is connected with the external voltage output voltage, and the output end is connected with the positive input end of the second impedance matching circuit; the second impedance matching circuit outputs the adjusted reference voltage to the adjustment comparing circuit.
The adjustment comparison circuit comprises an adjustment comparison circuit triode Q 2 Operational amplifier U 5 And a sampling resistor, wherein the real-time voltage and the reference voltage obtained by the sampling resistor pass through an operational amplifier U 5 Input-after-comparison adjusting comparison circuit triode Q 2 And the base electrode controls the output of the triode to achieve the purpose of constant voltage output.
The external control reference voltage circuit comprises an operational amplifier U 6 And triode Q 3 Operational amplifier U 6 Positive phase terminal and external control voltage V adj Is connected with the output end and the triode Q 3 A base electrode is connected; triode Q 3 Collector and the 24V front partThe output end of the stage power circuit is connected with the input end of the constant current source through the emitter through current expansion.
The heat conduction pool bridge circuit comprises a bridge resistor, an inner bridge resistor and a signal adjusting resistor; when no detection signal exists, the signal adjusting resistor can stabilize the output signal of the heat conducting pool near the zero point; when the internal bridge is out of balance, the bridge will generate a signal C s+ 、C s- And are respectively connected to the positive and negative input ends of the operational amplifier of the signal conditioning circuit of the heat conducting pool.
The thermal conductivity cell signal conditioning circuit comprises a subtracting circuit, a zero reference circuit and a thermal conductivity cell signal conditioning and amplifying circuit; the subtracting circuit comprises an operational amplifier U 7 A resistor; the zero-setting reference circuit comprises a voltage dividing resistor; the thermal conductivity cell signal conditioning and amplifying circuit comprises an operational amplifier U 8 A resistor; the subtraction circuit conducts heat Chi Dianqiao signal C s+ 、C s- Conditioned to a single-ended output signal and connected to an operational amplifier U through a resistor 8 A normal phase input; the 5V reference voltage obtains corresponding divided voltage through a voltage dividing resistor of the zeroing reference circuit and outputs the corresponding divided voltage to the operational amplifier U 8 Negative phase input terminal.
The beneficial technical effects of the utility model are as follows:
the chromatograph heat conduction pool detection circuit provided by the utility model has high sensitivity, and is easy to carry out the balanced configuration of the bridge resistance of the heat conduction pool; external control can be realized; meets the requirements of power supply, signal conditioning and output of a chromatograph thermal conductivity cell detector.
Drawings
FIG. 1 is a schematic diagram of a detection circuit of a thermal conductivity cell of a chromatograph according to the present utility model;
FIG. 2 is a schematic diagram of a constant current source circuit of a thermal conductivity cell of a chromatograph provided by the utility model;
FIG. 3 is a schematic diagram of a 24V pre-stage power supply circuit of a thermal conductivity cell of a chromatograph provided by the utility model;
FIG. 4 is a schematic diagram of an external control reference voltage circuit of a thermal conductivity cell of a chromatograph according to the present utility model;
FIG. 5 is a schematic diagram of a thermal conductivity cell bridge circuit of a chromatograph according to the present utility model;
fig. 6 is a schematic diagram of a signal conditioning circuit for thermal conductance Chi Dianqiao of a chromatograph according to the present utility model.
In the figure: 101-a constant current source circuit of a thermal conductivity cell; 102-24V front stage power supply circuit; 103-an external control reference voltage circuit; 104-a thermal conductance Chi Dianqiao circuit; 105-a thermal conductivity cell signal conditioning circuit; 201-a first impedance matching circuit; 202-a voltage amplifying circuit; 301-a second impedance matching circuit; 302-adjusting a comparison circuit; 501-internal bridge resistance; 601-subtracting circuitry; 602-zeroing a reference circuit; 603-a thermal conductivity cell signal conditioning and amplifying circuit.
Detailed Description
The utility model is described in further detail below with reference to the drawings and examples.
As shown in fig. 1, the thermal conductivity cell detection circuit includes a thermal conductivity cell constant current source circuit 101 that provides a constant current of 50-300 mA for a thermal conductivity cell bridge; a 24V pre-stage power supply circuit 102 that supplies a pre-stage power supply to the constant current source circuit; an external control reference voltage circuit 103 for performing impedance transformation on an external reference voltage for constant current source size control; the thermal conductance Chi Dianqiao circuit 104, which comprises a high thermal stability resistor and a thermal conductivity cell thermal resistance, forms a corresponding bridge; the thermal conductivity cell signal conditioning circuit 105 may condition, zero, amplify and output the thermal conductivity cell bridge signal to the corresponding voltage detection module.
As shown in fig. 2, the thermal conductivity cell constant current source circuit 101 provided in the present embodiment includes an impedance matching unit 201 and a voltage amplifying circuit 202. Wherein the first impedance matching circuit 201 and the external control reference voltage V in Through resistance R 21 Connection comprising an operational amplifier U 1 . The voltage amplifying circuit 202 comprises an operational amplifier and a resistor R 22 、R 23 An in-phase proportional operational amplifier is formed. The voltage amplifying circuit 202 outputs to the base of the current amplifying transistor.
Specifically, an operational amplifier U 1 Through resistor R 21 And V is equal to in A port connection for matching the external control reference voltage with the impedance and passing through an operational amplifier U 1 The output end is connected to the voltage amplifying circuit 202, and the voltage amplifying power thereof is represented by R 23 、R 24 And (5) determining.
As shown in fig. 3, the heat conduction pool 24 pre-stage power circuit provided in this embodiment includes a reference voltage chip U 3 The second impedance matching circuit 301 and the adjustment comparison circuit 302. Wherein U is 3 The second impedance matching circuit 301 outputs the regulated reference voltage to the regulation comparison circuit 302, which is formed by transistor Q 2 Operational amplifier U 5 Sampling resistor R 33 、R 34 、R 35 The composition is formed.
Specifically, 30V voltage is used as the reference voltage chip U 3 An input for outputting a stable reference voltage, and an output connected to the operational amplifier U 4 Is modulated U 4 The output end is connected to the operational amplifier U 5 Is provided. At the same time via Q 2 The 30V voltage of the spread current passes through a resistor R 33 、R 34 、R 35 . After partial pressure and sampling, input U 4 Is compared and input to Q 2 To control the output voltage of the pre-stage.
As shown in FIG. 4, the external control reference voltage circuit of the thermal conductivity cell provided in this embodiment includes an operational amplifier U 6 Triode Q 3 。
Specifically, an operational amplifier U 6 And triode Q 3 Form the jet-stage following and current-expanding action, and externally input control voltage V adj Input to operational amplifier U 6 Positive phase input terminal, via Q 3 And the amplified current is output to the constant current source input control end Vin.
Assuming that the bridge of the thermal conductivity cell needs to set 200mA current, setting external (data acquisition card, singlechip, etc.) V in =2v, which is directly input to the constant current source circuit of the thermal conductivity cell with a value of about 2V by external control reference voltage modulation. Back warp R 22 、R 23 Partial pressure of V' =r 23 /R 22 +R 23 ×V in . According to the characteristics of the operational amplifier, the voltage value of the positive terminal is equal toThe negative phase terminal voltage, so the bridge output current value is I=V'/R L 。Q 1 Collector Q is provided by 24V pre-stage power supply for current-expanding triode 1 -C input, Q 1 E is connected with the heat conducting cell bridge circuit and is connected with the sampling resistor through the bridge to form a loop.
As shown in fig. 5, the thermal conductivity cell bridge circuit provided in this embodiment includes an external bridge resistor: r is R 51 、R 52 、R 53 、R 54 The method comprises the steps of carrying out a first treatment on the surface of the An internal bridge resistor 501 comprising R 55 、R 56 、R 57 、R 58 Signal conditioning resistor R j1 、R j2 。
Specifically, when the component to be measured does not flow through the thermal conductivity cell measuring arm, the thermal conductivity cell bridge is in an equilibrium state and can pass through R j1 、R j2 And the signal output of the thermal conductivity cell is regulated to ensure that the thermal conductivity cell is near the zero point. When the internal bridge is out of balance, the bridge will generate a signal C s+ 、C s- And are respectively connected to the positive and negative input ends of the operational amplifier of the signal conditioning circuit of the heat conducting pool.
As shown in fig. 6, the thermal conductance Chi Dianqiao signal conditioning circuit provided in this embodiment includes a subtracting circuit 601, a zero reference circuit 602, and a thermal conductivity cell signal conditioning and amplifying circuit 603.
Specifically, an operational amplifier U 7 Resistor R 61 、R 62 、R 63 、R 64 The subtracter is configured to conduct heat Chi Dianqiao signal C s+ 、C s- Conditioned as a single ended output signal and passed through R 65 Connected to an operational amplifier U 8 A non-inverting input. At the same time, the reference voltage of 5V passes through the voltage dividing resistor R 67 、R 68 、R 69 Acquiring corresponding divided voltage and outputting to the operational amplifier U 8 Negative phase input terminal. Through operational amplifier U 9 And resistance R 56 、R 57 、R 70 、R 71 The constructed subtracting amplifier conditions the thermal conductivity cell signal. At this time, the thermal conductivity cell signal can be directly output to a data acquisition card and a chromatographic workstation for data recording and processing.
The present utility model has been described in detail with reference to the drawings and the embodiments, but the present utility model is not limited to the embodiments described above, and various changes can be made within the knowledge of those skilled in the art without departing from the spirit of the present utility model. The utility model may be practiced otherwise than as specifically described.
Claims (9)
1. A chromatograph thermal conductivity cell detection circuit, the circuit comprising: the device comprises a thermal conductivity cell constant current source circuit (101), a 24V front stage power supply circuit (102), an external control reference voltage circuit (103), a thermal conductivity Chi Dianqiao circuit (104) and a thermal conductivity cell signal conditioning circuit (105); the output end of the 24V front-stage power supply circuit (102) is connected with the input end of the heat conduction pool constant current source circuit (101) to provide a stable front-stage power supply circuit for the heat conduction pool constant current source circuit (101); the output end of the external control reference voltage circuit (103) is connected with the input end of the constant current source circuit (101) of the thermal conductivity cell, and the external reference voltage is used for controlling the size of the constant current source through impedance transformation; the output end of the heat conduction pool constant current source circuit (101) is connected with the input end of the heat conduction Chi Dianqiao circuit (104), and the heat conduction pool bridge circuit (104) comprises a high heat stable resistor and a heat conduction pool heat resistance to form a corresponding bridge; the output end of the heat conduction Chi Dianqiao circuit (104) is connected with the input end of the heat conduction pool signal conditioning circuit (105), and signals of the heat conduction pool bridge circuit (104) are conditioned, zeroed and amplified and then output to the corresponding voltage detection module.
2. The chromatograph thermal conductivity cell detection circuit according to claim 1, characterized in that the thermal conductivity cell constant current source circuit (101) comprises a first impedance matching circuit (201) and a voltage amplifying circuit (202); the first impedance matching circuit (201) includes an operational amplifier U 1 And a resistor connected with the external control reference voltage V in Connected, operational amplifier U 1 The output end is connected with a voltage amplifying circuit (202).
3. A chromatograph thermal conductivity cell detection circuit according to claim 2, wherein said voltage amplification circuit (202) comprisesCalculation amplifier U 2 And an amplifying ratio control resistor, an operational amplifier U 2 Output end and current output power triode Q 1 The base is connected.
4. A chromatograph thermal conductivity cell detection circuit according to claim 3, characterized in that said voltage amplifying circuit (202) comprises a current output power transistor Q 1 Current output power triode Q 1 The collector is connected with a 24V pre-stage power circuit (102), and the emitter is connected with a thermal conductance Chi Dianqiao circuit (104).
5. The chromatograph thermal conductivity cell detection circuit according to claim 1, wherein said 24V pre-stage power supply circuit (102) comprises a reference voltage chip U 3 A second impedance matching circuit (301) and an adjustment comparison circuit (302); reference voltage chip U 3 The input end is connected with an external voltage output voltage, and the output end is connected with a non-inverting input end of the second impedance matching circuit (301); the second impedance matching circuit (301) outputs the adjusted reference voltage to the adjustment comparison circuit (302).
6. The chromatography thermal conductivity cell detection circuit according to claim 5, wherein said adjustment comparison circuit (302) comprises an adjustment comparison circuit triode Q 2 Operational amplifier U 5 And a sampling resistor, wherein the real-time voltage and the reference voltage obtained by the sampling resistor pass through an operational amplifier U 5 Input-after-comparison adjusting comparison circuit triode Q 2 And the base electrode controls the output of the triode to achieve the purpose of constant voltage output.
7. A chromatograph thermal conductivity cell detection circuit according to claim 1, characterized in that said external control reference voltage circuit (103) comprises an operational amplifier U 6 And triode Q 3 Operational amplifier U 6 Positive phase terminal and external control voltage V adj Is connected with the output end and the triode Q 3 A base electrode is connected; triode Q 3 Collector and output end of the 24V pre-stage power circuit (102)And the connection is output from the emitter to the input end of the constant current source through current expansion.
8. The chromatograph thermal conductivity cell detection circuit of claim 1, wherein said thermal conductivity Chi Dianqiao circuit (104) comprises a bridge resistor, an inner bridge resistor (501) and a signal conditioning resistor; when no detection signal exists, the signal adjusting resistor can stabilize the output signal of the heat conducting pool near the zero point; when the internal bridge is out of balance, the bridge will generate a signal C s+ 、C s- And are respectively connected to the non-inverting and inverting input ends of the operational amplifier of the thermal conductivity cell signal conditioning circuit (105).
9. A chromatograph thermal conductivity cell detection circuit according to claim 1, characterized in that said thermal conductivity cell signal conditioning circuit (105) comprises a subtracting circuit (601) and a zeroing reference circuit (602), and a thermal conductivity cell signal conditioning and amplifying circuit (603); the subtracting circuit (601) includes an operational amplifier U 7 A resistor; the zeroing reference circuit (602) comprises a voltage dividing resistor; the thermal conductivity cell signal conditioning and amplifying circuit (603) comprises an operational amplifier U 8 A resistor; subtracting circuit (601) outputs heat conductance Chi Dianqiao signal C s+ 、C s- Conditioned to a single-ended output signal and connected to an operational amplifier U through a resistor 8 A normal phase input; the 5V reference voltage obtains corresponding divided voltage through a voltage dividing resistor of a zeroing reference circuit (602) and outputs the corresponding divided voltage to an operational amplifier U 8 Negative phase input terminal.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202223447556.4U CN220340135U (en) | 2022-12-22 | 2022-12-22 | Chromatograph heat conduction pool detection circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202223447556.4U CN220340135U (en) | 2022-12-22 | 2022-12-22 | Chromatograph heat conduction pool detection circuit |
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| Publication Number | Publication Date |
|---|---|
| CN220340135U true CN220340135U (en) | 2024-01-12 |
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|---|---|---|---|
| CN202223447556.4U Active CN220340135U (en) | 2022-12-22 | 2022-12-22 | Chromatograph heat conduction pool detection circuit |
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| CN (1) | CN220340135U (en) |
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- 2022-12-22 CN CN202223447556.4U patent/CN220340135U/en active Active
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