High-precision gas chromatograph

Abstract

The utility model discloses a high-precision gas chromatograph, which belongs to the technical field of gas detection and comprises a connecting pipe, a chromatographic column, at least one first sensor and at least one second sensor which are sequentially connected in series through the connecting pipe. The gas of the connecting pipe passes through the first sensor to enable the first sensor to generate a first electric signal, and the gas of the connecting pipe passes through the second sensor to enable the second sensor to generate a second electric signal. Under the condition of signal superposition of the first electric signal and the second electric signal, the noise of a baseline system is mutually superposed and eliminated, the noise level is not changed, meanwhile, signal peaks are effectively superposed and improved, the signal-to-noise ratio of the gas chromatograph is improved, the electric signals are generated by fully utilizing the to-be-detected gas, the signal conversion rate of the gas chromatograph is improved, and the detection accuracy is improved. The detection precision and sensitivity of the gas chromatograph are effectively improved, and high-precision detection of oil chromatography is realized.

Description

Technical Field

[0001] The utility model belongs to the technical field of gas detection, in particular to a high-precision gas chromatograph. Background Art

[0002] When the gas chromatography system detects component gases, it is mainly based on the different properties of different component gases. Driven by the carrier gas (mobile phase), the movement speeds in the chromatographic column are different. The gases with small molecular weight and small polarity flow out first, thus separating the gases one by one and then detecting them through the sensor.

[0003] Oil chromatography analysis systems usually use gas chromatography technology, which can complete a comprehensive analysis of gas components dissolved in insulating oil (such as hydrogen, methane, ethylene, ethane, acetylene, carbon monoxide and carbon dioxide) through a single injection. This analysis method can help detect whether there are faults such as overheating and discharge inside the transformer, thereby ensuring the safe and efficient operation of the power grid.

[0004] Currently, conventional oil chromatography faces problems such as large errors in online and offline data comparisons and unsatisfactory minimum detection limits, which affect the accuracy and timeliness of fault diagnosis. Utility Model Content

[0005] The utility model aims to improve the problem of low fault diagnosis accuracy of the existing gas chromatograph and provide a high-precision gas chromatograph.

[0006] The technical solutions to achieve the above objectives include the following:

[0007] A high-precision gas chromatograph comprises a connecting tube, a chromatographic column, at least a first sensor and a second sensor, wherein the chromatographic column, the first sensor and the second sensor are sequentially connected in series through the connecting tube;

[0008] The gas in the connecting pipe passes through the first sensor, so that the first sensor generates a first electrical signal, and the gas in the connecting pipe passes through the second sensor, so that the second sensor generates a second electrical signal.

[0009] In one embodiment, there are multiple sensors. After the gas passes through multiple sensors in sequence, the electrical signal generated by the last sensor is expressed by the formula:

[0010] Vn=cх(1-α) (n-1) хk;

[0011] In the formula, the electrical signal generated by the last sensor is Vn, the concentration of the gas component is c, the combustion rate of the gas each time it passes through the sensor is α, and the electrical signal generated by the complete combustion of the unit concentration gas is k.

[0012] In one embodiment, the total electrical signal generated by the multiple sensors is expressed as:

[0013] Vtotal = cхkх(1-(1-α) n ).

[0014] In one embodiment, the first sensor or the second sensor includes a detection bead, a first resistor, a power supply, and a sensing element. The detection bead, the power supply, the first resistor, and the sensing element are electrically connected in sequence, and the detection bead is connected to a connecting tube.

[0015] In one embodiment, the first sensor also includes a second resistor and a reference bead, the reference bead, power supply, second resistor, and sensing element are electrically connected in sequence, and the reference bead is connected to the detection bead; the detection bead, reference bead, first resistor, and second resistor form a bridge circuit, and the sensing element is used to monitor the bridge circuit.

[0016] In one embodiment, the detection beads are porous ceramic beads configured with catalysts, the reference beads are porous ceramic beads, and the catalyst is a mixture of one or more of platinum, palladium, nickel, gold, titanium dioxide, aluminum oxide, and silicon oxide.

[0017] In one embodiment, the connecting pipe includes a first pipeline, a second pipeline, and a third pipeline, and the gas chromatograph also includes a six-way valve and a quantitative ring. The first pipeline is connected to the six-way valve, and the six-way valve is connected to the first end of the second pipeline through the quantitative ring. The second end of the second pipeline is connected to the chromatographic column, and the six-way valve is also connected to the third pipeline.

[0018] In one embodiment, the connecting pipe also has a fourth pipeline, and the gas chromatograph also includes a first three-way valve and a second three-way valve; the first pipeline is connected to the first ends of the first three-way valve and the second three-way valve respectively, and the second end of the first three-way valve is connected to the second pipeline; the second end of the second three-way valve is connected to the six-way valve through the fourth pipeline, and the third ends of the first three-way valve and the second three-way valve are connected to the external environment.

[0019] In one embodiment, the gas chromatograph also includes a pressure switch and a pressure valve, the connecting pipe has an air inlet and an air outlet, the pressure switch and the pressure valve are installed on the first pipe of the connecting pipe, the air inlet is arranged on the first pipe, the air outlet is arranged on the third pipe, and the pressure switch and the pressure valve are located between the air inlet and the air outlet.

[0020] In one embodiment, the gas chromatograph further includes a solenoid valve, which is installed on the first pipeline and disposed close to the gas inlet.

[0021] The technical solution provided by the utility model has the following advantages and effects:

[0022] The chromatographic column, the first sensor, and the second sensor are connected in series in sequence through a connecting tube, and the gas to be detected enters the chromatographic column through the connecting tube. The chromatographic column is used to change the speed at which the gas flows out of the chromatographic column in the properties of different components in the gas, so that each component is separated and introduced into the first sensor and the second sensor in sequence to obtain the detection signal of each component. When each component gas passes through the first sensor, the gas burns flamelessly in the first sensor, causing the first sensor to generate a first electrical signal, and the gas that is not fully burned enters the second sensor, causing the second sensor to generate a second electrical signal. When the first electrical signal and the second electrical signal are superimposed, the baseline system noise is superimposed and eliminated, and the noise level remains unchanged. At the same time, the signal peak is effectively superimposed and enhanced, thereby improving the signal-to-noise ratio of the gas chromatograph, and making full use of the electrical signal generated by the gas to be detected, improving the signal conversion rate of the gas chromatograph, effectively improving the detection accuracy and sensitivity of the gas chromatograph, and realizing high-precision detection of oil chromatography. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The accompanying drawings herein show specific examples of the technical solutions described in the present utility model, and together with the specific implementation methods constitute a part of the specification, and are used to explain the technical solutions, principles and effects of the present utility model.

[0024] Unless otherwise specified or defined, the same reference numerals in different drawings represent the same or similar technical features, and the same or similar technical features may also be represented by different reference numerals.

[0025] Figure 1 A schematic diagram of a high-precision gas chromatograph in one embodiment of the utility model Figure 1 ;

[0026] Figure 2 A schematic diagram of a high-precision gas chromatograph in one embodiment of the utility model Figure 2 ;

[0027] Figure 3 is a circuit diagram of the first sensor or the second sensor in one embodiment of the utility model;

[0028] Figure 4 It is a comparison spectrum of electrical signals in one embodiment of the utility model;

[0029] Figure 5 This is a schematic diagram of a six-way valve in an embodiment of the utility model;

[0030] Figure 6 The working principle of the six-way valve in one embodiment of the utility model is Figure 1 ;

[0031] Figure 7 The working principle of the six-way valve in one embodiment of the utility model is Figure 2 ;

[0032] Description of reference numerals:

[0033] 100. Gas chromatograph; 1. Air inlet; 2. Connecting pipe; 3. Six-way valve; 4. Chromatographic column; 5. First sensor; 51. Detection beads; 52. Reference beads; 53. First resistor; 54. Second resistor; 55. Sensing element; 56. Power supply; 6. Second sensor; 7. Air outlet; 8. Quantitative loop; 9. External environment; 11. First three-way valve; 12. Second three-way valve; 13. Solenoid valve; 14. First pipeline; 15. Second pipeline; 16. Third pipeline; 17. Fourth pipeline; 18. Pressure switch; 19. Pressure valve. DETAILED DESCRIPTION

[0034] In order to facilitate the understanding of the present invention, specific embodiments of the present invention will be described in more detail below with reference to the accompanying drawings.

[0035] Unless otherwise specified or defined, the "first, second..." used in this article is merely used to distinguish names and does not represent a specific quantity or order.

[0036] Unless specifically stated or defined otherwise, the term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0037] It should be noted that when a component is considered to be "fixed to" another component, it can be directly fixed to the other component or there can be a central component; when an component is considered to be "connected to" another component, it can be directly connected to the other component or there can be a central component at the same time; when an component is considered to be "installed on" another component, it can be directly installed on the other component or there can be a central component at the same time. When an component is considered to be "set on" another component, it can be directly set on the other component or there can be a central component at the same time.

[0038] like Figures 1 to 3As shown, a high-precision gas chromatograph 100 includes a connecting tube 2, a chromatographic column 4, at least a first sensor 5 and a second sensor 6. The chromatographic column 4, the first sensor 5 and the second sensor 6 are sequentially connected in series through the connecting tube 2; the gas in the connecting tube 2 passes through the first sensor 5, so that the first sensor 5 generates a first electrical signal, and the gas in the connecting tube 2 passes through the second sensor 6, so that the second sensor 6 generates a second electrical signal. The chromatographic column 4, the first sensor 5 and the second sensor 6 are sequentially connected in series through the connecting tube 2, and the gas to be detected enters the chromatographic column 4 through the connecting tube 2. The chromatographic column 4 is used to change the speed at which the gas flows out of the chromatographic column 4 in different properties of the gas, so that each component is separated, and is sequentially introduced into the first sensor 5 and the second sensor 6 to obtain the detection signal of each component. When each component gas passes through the first sensor 5, the gas burns flamelessly in the first sensor 5, causing the first sensor 5 to generate a first electrical signal. The gas that is not fully burned enters the second sensor 6, and causes the second sensor 6 to generate a second electrical signal. When the first electrical signal and the second electrical signal are superimposed, the baseline system noise is superimposed on each other and the noise level remains unchanged. At the same time, the signal peak is effectively superimposed and enhanced, thereby improving the signal-to-noise ratio of the gas chromatograph 100, and making full use of the electrical signal generated by the gas to be tested, improving the signal conversion rate of the gas chromatograph 100, and effectively improving the detection accuracy and sensitivity of the gas chromatograph 100, thereby realizing high-precision detection of oil chromatography.

[0039] In this embodiment, two or more sensors are connected in series, and the gas to be tested that has not been completely burned after passing through the first sensor is detected again by the secondary sensor to generate a response signal. The detection and recording system forms a final corrected chromatogram by integrating the results of the two sensors. A signal collector can be used to collect multiple electrical signals to obtain a spectrum. Figure 4 As shown, by signal superposition after spectrum translation, baseline system noise is superimposed and eliminated, the noise level remains unchanged, and the signal peak is effectively superimposed and improved, thereby improving the signal-to-noise ratio of the gas chromatograph 100. At the same time, the two-stage or multi-stage detection sensor greatly improves the reliability of the gas chromatograph 100, and the software algorithm can be used to adjust the parameters and eliminate abnormal interference when a detector is abnormal by monitoring the sensor status, thereby ensuring stable and reliable operation of the system. In this embodiment, the sensor is a hydrogen flame ionization detector or a thermal conductivity detector.

[0040] After experimental verification, the spectra of the two-stage sensor are Figure 4 The black and red spectra are integrated and superimposed after lateral shift, and the final spectrum is blue, in which the growth of each gas reaches:

[0041] Components H2 CO CH4 C2H4 C2H2 C2H6 growth rate 24％ 62％ 60％ 49％ 48％ 67％

[0042] That is, the sensitivity of each gas component has been significantly improved. This data is only one of the verified examples in this embodiment. If the installation structure and series collection form of the sensor are further improved, it can be further improved.

[0043] In addition, there are multiple sensors. After the gas passes through multiple sensors in sequence, the electrical signal generated by the last sensor is expressed by the formula:

[0044] Vn=cх(1-α) (n-1) хk;

[0045] In the formula, the electrical signal generated by the last sensor is Vn, the concentration of the gas component is c, the combustion rate of the gas each time it passes through the sensor is α, and the electrical signal generated by the complete combustion of the unit concentration gas is k.

[0046] In this embodiment, each component of the gas passes through multiple sensors in sequence, and the multiple sensors generate electrical signals of different strengths. It can be seen from the above formula that the electrical signal sensed by the last sensor is the weakest, but the multiple electrical signals generated by multiple sensors are superimposed, and the signal peaks generated by multiple sensors at the same time are effectively superimposed, thereby further improving the signal-to-noise ratio of the gas chromatograph 100. Moreover, different gases have different combustion rates when passing through the sensors. Therefore, the use of multiple sensors can ensure that when the gas passes through the gas chromatograph 100, the gas chromatograph 100 can detect multiple components of gas and generate stronger electrical signals, and its detection sensitivity is improved.

[0047] In addition, the total electrical signal generated by multiple sensors is expressed as:

[0048] Vtotal = cхkх(1-(1-α) n ).

[0049] In this embodiment, it can be seen from the above formula that the more sensors there are, the stronger the electrical signal generated by the gas passing through the gas chromatograph 100; and, in the event that one of the sensors fails, the remaining sensors can also generate electrical signals.

[0050] like Figure 1 and Figure 3 As shown, the first sensor 5 or the second sensor 6 includes a detection bead 51, a first resistor 53, a power source 56, and a sensing element 55. The detection bead 51, the power source 56, the first resistor 53, and the sensing element 55 are electrically connected in sequence, and the detection bead 51 is connected to the connecting pipe 2. In this embodiment, when the gas passes through the detection bead 51, the detection bead 51 causes the gas to undergo a flameless combustion reaction, thereby increasing the temperature of the first resistor 53. After the sensing element 55 senses the temperature of the first resistor 53, it generates an electrical signal, thereby further realizing the gas detection function of the gas chromatograph 100.

[0051] like Figure 3 As shown, the first sensor 5 also includes a second resistor 54 and a reference bead 52. The reference bead 52, the power supply 56, the second resistor 54, and the induction element 55 are electrically connected in sequence, and the reference bead 52 is connected to the detection bead 51; the detection bead 51, the reference bead 52, the first resistor 53, and the second resistor 54 form a bridge circuit, and the induction element 55 is used to monitor the bridge circuit. The detection bead 51 and the reference bead 52 are both porous ceramic beads, and the detection bead 51 has a catalyst, which is a mixture of one or more of platinum, palladium, nickel, gold, titanium dioxide, aluminum oxide, and silicon oxide. When no gas passes through the sensor, the bridge circuit composed of the detection bead 51, the reference bead 52, the first resistor 53, and the second resistor 54 is in a stable state. When the gas passes through the sensor, the gas enters the detection bead 51 and the reference bead 52 respectively. Since the detection bead 51 has a catalyst, the gas reacts with the catalyst in the detection bead 51, and the first resistor 53 generates high temperature. When the gas enters the reference bead 52, since the reference bead 52 has no catalyst, the reference bead 52 cannot react with the gas to produce flameless combustion, which will cause the voltage of the bridge circuit to become unstable, thereby causing the sensing element 55 to generate an electrical signal.

[0052] like Figure 1 and Figure 2 As shown, the connecting pipe 2 includes a first pipeline 14, a second pipeline 15, and a third pipeline 16. The gas chromatograph 100 also includes a six-way valve 3 and a quantitative ring 8. The first pipeline 14 is connected to the six-way valve 3. The six-way valve 3 is connected to the first end of the second pipeline 15 through the quantitative ring 8. The second end of the second pipeline 15 is connected to the chromatographic column 4. The six-way valve 3 is also connected to the third pipeline 16. In this embodiment, Figure 5 As shown in a, the six external interfaces (31, 32, 33, 34, 35, 36) of the six-way valve 3 are connected in pairs by the middle through pipe. When the six-way valve 3 is closed, Figure 5 As shown in b, when opening, the connected parts in the middle rotate 60°, as shown in Figure 5 c. Then the external connection of the six-way valve 3 is introduced. The normal entire gas path system (the air intake part of the gas path may also be the injection port, which is injected with a micro-injector. In addition, what is discussed here is gas chromatography, and the liquid phase may be slightly different.) looks like the following. Two of the ports (35 and 36) are connected to the air intake and outlet respectively, two ports (32 and 33) are connected to the chromatographic column 4, and the remaining two ports (31 and 34) are connected to the adjacent ports. The sample in this section of the tube of the middle quantitative ring 8 is used for injection. The flow direction of the gas to be detected is the direction of the solid arrow. It enters directly from the injection port and then blows out. The carrier gas in the chromatographic column 4 is in the direction of the hollow arrow. If injection is required, open the six-way valve 3, and the internal direction of the entire six-way valve 3 immediately becomes as follows Figure 7 As shown: the quantitative ring 8 is connected to both ends of the chromatographic column 4, so the carrier gas brings the remaining gas in the middle into the chromatographic column 4.

[0053] like Figure 1 and Figure 2 As shown, the connecting pipe 2 also has a fourth pipeline 17, and the gas chromatograph 100 also includes a first three-way valve 11 and a second three-way valve 12; the first pipeline 14 is connected to the first ends of the first three-way valve 11 and the second three-way valve 12 respectively, and the second end of the first three-way valve 11 is connected to the second pipeline 15; the second end of the second three-way valve 12 is connected to the six-way valve 3 through the fourth pipeline 17, and the third ends of the first three-way valve 11 and the second three-way valve 12 are connected to the external environment 9. In this embodiment, when the gas chromatograph 100 detects gas, the gas flows from the gas inlet 1, the first pipeline 14, the fourth pipeline 17, and the second pipeline 15 to the first sensor 5 and the second sensor 6 in sequence, and then the third end of the first three-way valve 11 is opened, and the excess gas is discharged to the external environment 9. Since the gas chromatograph 100 is subjected to long-term detection, garbage will remain in the sensor, the six-way valve 3 and the pipeline; therefore, when the gas chromatograph 100 needs to be cleaned, the gas flows in sequence from the first pipeline 14, the second pipeline 15, and the fourth pipeline 17, and then the first three-way valve 11 is closed, and the third end of the second three-way valve 12 is opened. The gas flows in the reverse direction through the sensor, cleans the residual garbage in the sensor and the six-way valve 3, and is discharged to the external environment 9 through the fourth pipeline 17, thereby completing the cleaning of the gas chromatograph 100.

[0054] like Figure 1 and Figure 2 As shown, the gas chromatograph 100 also includes a pressure switch 18 and a pressure valve 19. The connecting pipe 2 has an air inlet 1 and an air outlet 7. The pressure switch 18 and the pressure valve 19 are installed on the first pipeline 14 of the connecting pipe 2. The air inlet 1 is arranged on the first pipeline 14, and the air outlet 7 is arranged on the third pipeline 16. The pressure switch 18 and the pressure valve 19 are located between the air inlet 1 and the air outlet 7. In this embodiment, the pressure switch 18 adopts a high-precision, high-stability pressure sensor and a transmission circuit, and then uses a dedicated CPU modular signal processing technology to realize the detection, display, alarm and control signal output of the medium pressure signal. The pressure valve 19 is an important industrial equipment, and its main function is to control and adjust the pressure in the system. The specific function is to adjust the flow rate, set the flow rate according to the design requirements, automatically eliminate the flow deviation caused by the residual pressure head and pressure fluctuation of the pipeline, and keep the set flow rate unchanged.

[0055] like Figure 1 and Figure 2As shown, the gas chromatograph 100 also includes a solenoid valve 13, which is installed on the first pipeline 14 and is arranged near the air inlet 1. In this embodiment, the solenoid valve 13 is an industrial device controlled by electromagnetics, which is a basic automation element used to control fluids. It belongs to an actuator and is not limited to hydraulics and pneumatics. It is used in industrial control systems to adjust the direction, flow rate, speed and other parameters of the medium. The solenoid valve 13 can be used in conjunction with different circuits to achieve the desired control, and the accuracy and flexibility of the control can be guaranteed.

[0056] When quoting drawing descriptions, new features that appear are described; in order to avoid repeated quotations of drawings resulting in less concise descriptions, features that have been described clearly will not be quoted in the drawings one by one.

[0057] The purpose of the above embodiments is to exemplarily reproduce and deduce the technical solution of the utility model, and to fully describe the technical solution, purpose and effect of the utility model. Its purpose is to make the public understand the disclosed content of the utility model more thoroughly and comprehensively, and it does not limit the protection scope of the utility model.

[0058] The above embodiments are not exhaustive enumerations based on the present invention, and there may be multiple other implementations not listed. Any replacement and improvement made without violating the concept of the present invention shall fall within the protection scope of the present invention.

Claims

1. A high-precision gas chromatograph, characterized in that: It comprises a connecting tube, a chromatographic column, at least a first sensor and a second sensor, wherein the chromatographic column, the first sensor and the second sensor are sequentially connected in series through the connecting tube; The gas in the connecting pipe passes through the first sensor so that the first sensor generates a first electrical signal, and the gas in the connecting pipe passes through the second sensor so that the second sensor generates a second electrical signal; The first sensor or the second sensor comprises a detection bead, a first resistor, a power supply, and a sensing element, wherein the detection bead, the power supply, the first resistor, and the sensing element are electrically connected in sequence, and the detection bead is connected to a connecting tube; The connecting pipe includes a first pipeline, a second pipeline, and a third pipeline. The gas chromatograph also includes a six-way valve and a quantitative ring. The first pipeline is connected to the six-way valve, and the six-way valve is connected to the first end of the second pipeline through the quantitative ring. The second end of the second pipeline is connected to the chromatographic column, and the six-way valve is also connected to the third pipeline.

2. The gas chromatograph according to claim 1, characterized in that There are multiple sensors. After the gas passes through multiple sensors in sequence, the electrical signal generated by the last sensor is expressed by the formula: Vn=cх(1-α) (n-1) x In the formula, the electrical signal generated by the last sensor is Vn, the concentration of the gas component is c, the combustion rate of the gas each time it passes through the sensor is α, and the electrical signal generated by the complete combustion of the unit concentration gas is k.

3. The gas chromatograph according to claim 2, characterized in that The total electrical signal generated by multiple sensors is expressed as: Vtotal = cхkх(1-(1-α) n ).

4. The gas chromatograph according to claim 1, characterized in that The first sensor also includes a second resistor and a reference bead. The reference bead, power supply, second resistor, and sensing element are electrically connected in sequence, and the reference bead is connected to the detection bead. The detection bead, reference bead, first resistor, and second resistor form a bridge circuit, and the sensing element is used to monitor the bridge circuit.

5. The gas chromatograph according to claim 1, characterized in that The connecting pipe also has a fourth pipeline, and the gas chromatograph also includes a first three-way valve and a second three-way valve; the first pipeline is connected to the first ends of the first three-way valve and the second three-way valve respectively, and the second end of the first three-way valve is connected to the second pipeline; the second end of the second three-way valve is connected to the six-way valve through the fourth pipeline, and the third ends of the first three-way valve and the second three-way valve are connected to the external environment.

6. The gas chromatograph according to claim 1, characterized in that The gas chromatograph also includes a pressure switch and a pressure valve. The connecting pipe has an air inlet and an air outlet. The pressure switch and the pressure valve are installed on the first pipeline of the connecting pipe. The air inlet is arranged on the first pipeline, and the air outlet is arranged on the third pipeline. The pressure switch and the pressure valve are located between the air inlet and the air outlet.

7. The gas chromatograph according to claim 6, characterized in that The gas chromatograph also includes a solenoid valve, which is installed on the first pipeline and arranged close to the gas inlet.

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