CN217688766U

CN217688766U - Thermal conductivity detection device

Info

Publication number: CN217688766U
Application number: CN202222186887.0U
Authority: CN
Inventors: 夏攀
Original assignee: Beijing Guoyi Precision Measurement Technology Co ltd
Current assignee: Beijing Guoyi Precision Measurement Technology Co ltd
Priority date: 2022-08-19
Filing date: 2022-08-19
Publication date: 2022-10-28
Anticipated expiration: 2032-08-19

Abstract

The utility model discloses a thermal conductance detection device, thermal conductance detection device includes: mix the gas structure, the sample pipeline, thermal conductivity cell and temperature mixing unit, mix the gas structure and be provided with the gas output that mixes of deriving the gas mixture, the sample to be measured has been placed to sample pipeline inside, the thermal conductivity cell includes reference arm and measuring arm, be connected with first inflow pipeline between the inflow end of reference arm and the gas output that mixes, the outflow end of reference arm is connected with first outflow pipeline with the one end of sample pipeline, be connected with the second inflow pipeline between the other end of sample pipeline and the inflow end of measuring arm, be provided with the heat transfer space in the temperature mixing unit, the at least part of first inflow pipeline and the at least part of second inflow pipeline are located the heat transfer space so that the gas mixture's of flow direction reference arm temperature and the gas mixture that flows to measuring arm carry out the heat exchange. The temperature of the mixed gas flowing to the reference arm is close to that of the mixed gas flowing to the measuring arm, and the reliability of the measured data of the thermal conductivity detection device is improved.

Description

Thermal conductivity detection device

Technical Field

The utility model belongs to the technical field of gaseous detection technique and specifically relates to a thermal conductance detection device is related to.

Background

Thermal conductivity detectors, which are the most common type of detector for gas chromatography, are instruments that measure various gases with different thermal conductivity, i.e., different rates of thermal conductivity.

The main element of the thermal conductivity detector is a thermal conductivity cell, the thermal conductivity cell is composed of a cell body, thermistors and corresponding circuits, symmetrical pore channels are arranged in the cell body, the thermistors with equal material, length and resistance are arranged in the corresponding pore channels, a plurality of thermistors form an electric bridge, when a constant direct current passes through the thermal conductivity cell, a hot wire is heated, and the electric bridge is balanced and has no signal output because the resistances of the thermistors are the same. The gas flow is input to the heat conduction detector, pure carrier gas flows through the thermistor of the reference arm, the carrier gas carries the measured gas to flow through the thermistor of the measurement arm, the heat of the thermistor can be taken away by the gas flow, the difference is generated between the resistance values of the thermistor in the reference arm and the thermistor in the measurement arm due to the fact that the heat conductivity of the carrier gas and the binary mixed gas of the measured gas is different from the heat conductivity of the pure carrier gas, the bridge is out of balance, the detector has voltage signal output, and the signal is amplified, temperature compensated and linearized through the processing circuit to become a measured value of the concentration of the measured gas.

However, in actual operation, due to some operation processes, the temperature of the gas reaching the measuring arm is different from the temperature of the gas reaching the reference arm, so that when data on the reference arm and the measuring arm are measured, the reliability of the measured data is reduced due to the difference in gas temperature.

SUMMERY OF THE UTILITY MODEL

The utility model discloses aim at solving one of the technical problem that exists among the prior art at least. Therefore, an object of the present invention is to provide a thermal conductivity detection device, which has reliable measurement data and high measurement accuracy.

According to the utility model discloses thermal conductance detection device, include: the gas mixing structure is provided with a gas mixing output end for leading out mixed gas; the device comprises a sample pipeline, a sample to be detected and a control circuit, wherein a sample to be detected is placed in the sample pipeline; the thermal conductivity cell comprises a reference arm and a measuring arm, a first inflow pipeline is connected between an inflow end of the reference arm and the gas mixing output end, a first outflow pipeline is connected between an outflow end of the reference arm and one end of the sample pipeline, and a second inflow pipeline is connected between the other end of the sample pipeline and an inflow end of the measuring arm; and the temperature mixing unit is internally provided with a heat exchange space, and at least part of the first inflow pipeline and at least part of the second inflow pipeline are positioned in the heat exchange space so as to exchange heat between the mixed gas flowing to the reference arm and the mixed gas flowing to the measuring arm.

According to the utility model discloses thermal conductance detection device, through setting up the temperature mixing unit, make the gas mixture that flows to the reference arm and the gas mixture that flows to the measuring arm carry out the heat exchange for the temperature of the gas mixture that flows to the reference arm is close with the temperature of the gas mixture that flows to the measuring arm, reduces the measured data error that causes because the temperature difference of gas mixture, promotes thermal conductance detection device's measured data reliability, promotes thermal conductance detection device's detection precision.

In some embodiments, the temperature mixing unit is configured in a plurality, and the plurality of temperature mixing units are spaced apart in a gas flow direction of the first inflow conduit or in a gas flow direction of the second inflow conduit.

In some embodiments, a plurality of the temperature mixing units comprises: a first temperature mixing unit, the first temperature mixing unit comprising: the heat conduction liquid is arranged in the first accommodating cavity; a first mixed temperature pipeline configured as a portion of the first inflow pipeline, at least a portion of the first mixed temperature pipeline being in contact with the thermally conductive liquid; a second mixed temperature pipeline configured as a part of the second inflow pipeline, the second mixed temperature pipeline being disposed in the first accommodation chamber to exchange heat with the first mixed temperature pipeline.

Specifically, the first mixed temperature pipeline includes: a first housing defining the first receiving chamber therein; the second shell is arranged on the outer side of the first shell and is spaced from the first shell, and the second shell and the first shell define a second containing cavity for mixed gas to flow.

In some embodiments, the second mixing temperature pipeline comprises: the branch pipelines are multiple and arranged on the peripheral wall of the main pipeline, and two ends of each branch pipeline are communicated with the main pipeline.

Specifically, each of the branch pipes includes: the device comprises an inclined pipe and an arc pipe, wherein one end of the inclined pipe is connected with the main pipeline, the distance between the central line of the inclined pipe and the central line of the main pipeline is gradually increased in the flowing direction of mixed gas in the main pipeline, and the arc pipe is connected between the other end of the inclined pipe and the main pipeline.

Further, an included angle α between the inclined tube and the main pipeline satisfies the following condition: alpha is more than or equal to 15 degrees and less than or equal to 30 degrees.

Optionally, an included angle between the flow direction of the mixture in the connecting portion of the circular arc pipe and the main pipeline and the flow direction of the mixture in the main pipeline is 120-165 °.

In some embodiments, the temperature mixing unit further comprises: a second temperature mixing unit disposed at one side of the first temperature mixing unit close to the thermal conductivity cell, the second temperature mixing unit including: a third housing, in which a third accommodating chamber is formed, and heat conducting liquid is accommodated in the third accommodating chamber; a third mixed temperature pipeline configured as a part of the first inflow pipeline and disposed in the third accommodation chamber; a fourth mixed temperature pipeline configured as a portion of the second inflow pipeline and disposed in the third receiving cavity.

Specifically, the third mixed-temperature pipeline and the fourth mixed-temperature pipeline are both configured as spiral pipes, and the third mixed-temperature pipeline and the fourth mixed-temperature pipeline are wound alternately.

Additional aspects and advantages of the invention will be set forth in part in the description which follows and, in part, will be obvious from the description, or may be learned by practice of the invention.

Drawings

The above and/or additional aspects and advantages of the present invention will become apparent and readily appreciated from the following description of the embodiments, taken in conjunction with the accompanying drawings of which:

fig. 1 is a schematic connection diagram of a thermal conductivity detection device according to an embodiment of the present invention;

fig. 2 is a schematic structural diagram of a first temperature mixing unit according to an embodiment of the present invention.

Reference numerals:

the gas mixing structure 100, the sample pipeline 200, the thermal conductivity cell 300 and the temperature mixing unit 400;

the temperature measuring device comprises a reference arm 1, a measuring arm 2, a first inflow pipeline 3, a first outflow pipeline 4, a second inflow pipeline 5, a first temperature mixing unit 7, a first temperature mixing pipeline 71, a second temperature mixing pipeline 72, a main pipeline 721, a branch pipeline 722, an inclined pipe 722a, an arc pipe 722b, a first accommodating cavity 73, a second accommodating cavity 74, a first shell 75, a second shell 76, a second temperature mixing unit 8, a third shell 81, a third accommodating cavity 82, a third temperature mixing pipeline 83, a fourth temperature mixing pipeline 84, a reference arm detection point 91 and a measurement detection point arm 92.

Detailed Description

Reference will now be made in detail to the embodiments of the present invention, examples of which are illustrated in the accompanying drawings, wherein like reference numerals refer to the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary only for explaining the present invention, and should not be construed as limiting the present invention.

A thermal conductivity detection device according to an embodiment of the present invention is described below with reference to fig. 1-2.

According to the utility model discloses thermal conductance detection device, include: mix gas structure 100, sample pipeline 200, thermal conductivity cell 300 and temperature mixing unit 400, mix gas structure 100 and be provided with the gas output that mixes of leading out the gas mixture, the sample to be measured has been placed to sample pipeline 200 inside, thermal conductivity cell 300 includes reference arm 1 and measuring arm 2, be connected with first influent line 3 between the inflow end of reference arm 1 and the gas output that mixes, the outflow end of reference arm 1 and the one end of sample pipeline 200 are connected with first outflow pipeline 4, be connected with second inflow pipeline 5 between the other end of sample pipeline 200 and the inflow end of measuring arm 2, be provided with the heat transfer space in the temperature mixing unit 400, at least part of first inflow pipeline 3 and at least part of second inflow pipeline 5 are located the heat transfer space so that the temperature of the gas mixture that flows to reference arm 1 and the gas mixture that flows to measuring arm 2 carry out the heat exchange.

The gas mixture output end is connected with one end of the first inflow pipeline 3, the other end of the first inflow pipeline 3 is connected with the inflow end of the reference arm 1, the outflow end of the reference arm 1 is connected with one end of the first outflow pipeline 4, the other end of the first outflow pipeline 4 is connected with one end of the sample pipeline 200, the other end of the sample pipeline 200 is connected with one end of the second inflow pipeline 5, and the other end of the second inflow pipeline 5 is connected with the inflow end of the measurement arm 2, which is a gas circuit of the thermal conductivity detection device.

It can be understood that the thermal conductivity cell 300 includes a cell body, four identical thermistors, namely, a resistor R1, a resistor R2, a resistor R3, and a resistor R4, and a thermistor and a corresponding circuit, the four thermistors are combined into a bridge, and the four thermistors are respectively disposed in a cell cavity in the cell body and are closed to form a reference arm 1 and a measurement arm 2, wherein the resistor R1 and the resistor R3 are formed as the reference arm 1 of the thermal conductivity cell 300, and the resistor R2 and the resistor R4 are formed as the measurement arm 2 of the thermal conductivity cell 300. The voltage is applied to the input end of the bridge, and the four thermistors are completely the same, so that the output voltage of the output end of the bridge is 0. When a current flows through the thermistors, heat is generated, the temperature of the thermistors rises with the increase of the resistance value, and the output voltage of the bridge is always 0 because the four thermistors are completely the same. The mixed gas is introduced into the whole gas circuit, and when the mixed gas flows to the periphery of the thermistor, the mixed gas exchanges heat with the thermistor to take away heat of the thermistor, so that the resistance value of the thermistor can be changed, and the heat conductivity coefficients of different mixed gases are different, so that different mixed gases are introduced into the thermistor, and the resistance value of the thermistor can be changed differently.

The utility model discloses during the gas mixture firstly flows into reference arm 1, the gas mixture carries out the heat exchange with the thermistor of reference arm 1, during the gas mixture flows into sample pipeline 200 afterwards, the sample that awaits measuring in gas mixture and the sample pipeline 200 of predetermineeing combines, causes to predetermine gas composition content change in the gas mixture, consequently, the gas mixture that flows out and flow direction measuring arm 2 from sample pipeline 200 and the gas mixture that flows out and flow direction reference arm 1 from gas mixture structure 100 exist the gas composition difference, the utility model discloses for the convenience of description will both be referred to as the gas mixture jointly.

Because the gas mixture flowing to the measuring arm 2 and the gas mixture flowing to the reference arm 1 have gas component difference, the heat conductivity coefficient of the gas mixtures is different, the heat quantity of the heat sensitive resistor carried away by the same gas mixture flowing from the gas mixture output end is different when the same gas mixture flows through the reference arm 1 and the measuring arm 2, so that the resistance value change of the resistor R2 and the resistor R4 is different from the resistance value change of the resistor R1 and the resistor R3, the bridge is out of balance, a voltage signal appears at the output end of the bridge, the magnitude of the voltage signal completely depends on the change of the gas content caused by the combination of the sample to be measured and the preset gas in the gas mixture, namely the voltage signal can show the gas quantity of the preset gas adsorbed by the sample to be measured. Draw a curve promptly for adsorbing the peak to the change of the output voltage who gathers along with time, the area that this curve contains is corresponding to the sample that awaits measuring and adsorbs the size of predetermineeing the gas quantity, consequently the utility model discloses a thermal conductance detection device detectable awaits measuring sample and adsorbs predetermineeing the gas quantity to and the information such as specific surface area or the aperture distribution of the sample that awaits measuring.

In order to control the variable, the reference arm and the measuring arm are generally connected in series, and the same mixed gas flow flowing out of the mixed gas output end firstly flows through the reference arm, then flows through the sample pipeline and finally flows through the measuring arm, so that the mixed gas flowing through the reference arm and the mixed gas flowing through the measuring arm only have the difference of preset gas quantity, and the measuring precision of the detecting device is improved. However, in actual operation, the mixed gas flowing out of the reference arm already participates in primary heat exchange with the resistor R1 and the resistor R3, and when the mixed gas flows through the sample pipeline, after some operations, the temperature of the mixed gas changes again, which causes a difference between the temperature of the mixed gas flowing into the measurement arm and the temperature of the mixed gas flowing into the reference arm, so that the mixed gas flowing through the reference arm and the mixed gas flowing through the measurement arm have a difference not only in the content of the preset gas, but also in the temperature of the mixed gas, and the temperature difference of the mixed gas causes a difference in the amount of heat taken away from the thermistor, so that the magnitude of the voltage signal appearing at the output end of the bridge depends on not only the change in the gas content caused by the combination of the sample to be measured and the preset gas in the mixed gas, but also the temperature change of the mixed gas generated after the mixed gas flows through the sample to be measured, and the result presented by the voltage signal is inaccurate, resulting in the reduction of the reliability of the measured data.

Therefore the utility model discloses be provided with temperature mixing unit 400, be provided with the heat transfer space in the temperature mixing unit 400, the gas mixture in the first income pipeline 3 flows to reference arm 1, the gas mixture in the second income pipeline 5 flows to measuring arm 2, the at least part of the first income pipeline 3 and the at least part of the second income pipeline 5 are located the heat transfer space, so that the gas mixture that flows to reference arm 1 and the gas mixture that flows to measuring arm 2 carry out the heat exchange, make the temperature of the gas mixture that flows to reference arm 1 and the temperature of the gas mixture that flows to measuring arm 2 close, reduce the measured data error that causes because the temperature difference of gas mixture, promote the measured data reliability of thermal conductance detection device.

According to the utility model discloses thermal conductance detection device, through setting up temperature mixing unit 400, make the gas mixture that flow direction consulted arm 1 and the gas mixture that flows to measuring arm 2 carry out the heat exchange for the temperature of the gas mixture that flow direction consulted arm 1 is close with the temperature of the gas mixture that flows to measuring arm 2, reduces because the measured data error that the temperature difference of gas mixture caused, promotes thermal conductance detection device's measured data reliability, promotes thermal conductance detection device's detection precision.

In some embodiments of the present invention, the thermal conductivity detector measures the specific surface area of the sample to be measured by using a dynamic nitrogen adsorption method, and the measurement process of one embodiment is described in detail below.

The gas mixing structure 100 is suitable for guiding out a mixed gas of nitrogen and helium, wherein the nitrogen is an adsorption gas, the helium is a carrier gas, and the heat conductivity coefficient of the helium is nearly six times larger than that of the nitrogen, so that the heat conductivity coefficients of the mixed gas with different helium-nitrogen ratios are different. The method comprises the steps of placing a sample pipeline 200 in a liquid nitrogen (-196 ℃) environment, introducing mixed gas into a gas circuit, enabling the helium-nitrogen mixed gas to flow into a reference arm 1 firstly, enabling the helium-nitrogen mixed gas to exchange heat with a thermistor of the reference arm 1, enabling the helium-nitrogen mixed gas to flow into the sample pipeline 200, enabling the nitrogen to be adsorbed by a sample to be detected and enabling the helium not to be adsorbed by the sample to be detected at the temperature of the liquid nitrogen, enabling the helium-nitrogen proportion of the helium-nitrogen mixed gas flowing out of the sample pipeline 200 to change, enabling the helium-nitrogen mixed gas flowing into a measuring arm 2 to exchange heat with the thermistor of the measuring arm 2, enabling the resistance value changes of a resistor R2 and a resistor R4 to be different from the resistance value changes of the resistor R1 and a resistor R3, enabling a voltage signal to appear at the output end of a bridge, drawing a curve which is an adsorption peak along with the change of time of the acquired voltage signal, and enabling the area of the curve to correspond to the amount of the adsorbed nitrogen gas of the sample to be detected, and obtaining the specific surface area of the sample to be detected. Similarly, when the sample to be detected is in the liquid nitrogen environment and reaches saturation, the sample pipeline 200 is taken out from the liquid nitrogen environment, the temperature of the sample pipeline 200 is gradually increased to room temperature, all nitrogen absorbed by the sample to be detected can be desorbed, at the moment, an electric signal can be obtained at the output end of the electric bridge, the electric signal is just opposite to the positive voltage and the negative voltage during absorption, a curve is drawn by the change of the collected voltage signal along with time, the curve is a desorption peak, and the area of the desorption peak is equal to the area of the absorption peak.

It can be understood that the temperature of the he-nox flowing out of the sample line 200 is much lower than that of the he-nox flowing into the reference arm 1, and by providing the temperature mixing unit 400, the mixture flowing to the reference arm 1 and the mixture flowing to the measurement arm 2 are heat-exchanged, so that the temperature of the mixture flowing to the reference arm 1 and the temperature of the mixture flowing to the measurement arm 2 are close to each other, thereby improving the reliability of the measurement data of the thermal conductivity detection apparatus.

In some embodiments of the present invention, a reference arm detection point 91 is provided on the first outflow line 4, and a measurement arm detection point 92 is provided on the second outflow line.

In some embodiments of the present invention, the temperature mixing unit 400 is configured in plurality, and the plurality of temperature mixing units 400 are spaced apart in the gas flow direction of the first inflow pipe 3 or in the gas flow direction of the second inflow pipe 5.

Through setting up a plurality of temperature mixing unit 400, can make the gas mixture in the first income pipeline 3 and the gas mixture in the second income pipeline 5 carry out the heat exchange many times for the temperature of the gas mixture that flows to reference arm 1 is close with the temperature of the gas mixture that flows to measuring arm 2, further promotes thermal conductance detection device's measured data reliability.

And the gas inflow direction of the first inflow pipe 3 is from the gas mixing structure 100 to the reference arm 1, the gas flow direction of the second inflow pipe 5 is from the sample pipe 200 to the measurement arm 2, and the plurality of temperature mixing units 400 are spaced in the gas flow direction of the first inflow pipe 3 or in the gas flow direction of the second inflow pipe 5, it can be understood that the temperature difference between the gas mixture just flowing out from the sample pipe 200 and the gas mixture flowing to the reference arm 1 is the largest, and thus the temperature difference between the gas mixture flowing into the first inflow pipe 3 and the gas mixture flowing into the second inflow pipe 5 in the temperature mixing units 400 far from the reference arm 1 or the measurement arm 2 is the largest, and by providing the plurality of temperature mixing units 400, the temperature of the gas mixture flowing to the reference arm 1 and the temperature of the gas mixture flowing to the measurement arm 2 exchange heat with each other during the flow, the temperatures gradually tend to be the same, and after passing through the plurality of temperature mixing units 400, the temperature mixing units 400 close to the first inflow pipe 3 in the temperature mixing units 400 at the reference arm 1 or the measurement arm 2, and thus the temperature mixing units 5 flowing into the first inflow pipe 5 can be further spaced apart, and the temperature mixing units 400 can detect the reliability of the gas flowing into the measurement arm, and the measurement arm 5.

In some embodiments of the present invention, as shown in fig. 1, the plurality of temperature mixing units 400 includes: a first temperature mixing unit 7 and a second temperature mixing unit 8, wherein the second temperature mixing unit 8 is arranged at one side of the first temperature mixing unit 7 close to the heat conducting pool 300.

The first temperature mixing unit 7 includes: the first accommodating cavity 73, the first mixed temperature pipeline 71 and the second mixed temperature pipeline 72, wherein the first mixed temperature pipeline 71 is configured as a part of the first inflow pipeline 3, and the second mixed temperature pipeline 72 is configured as a part of the second inflow pipeline 5, for convenience of description, therefore, a part of the first inflow pipeline 3 in the first temperature mixing unit 7 is referred to as the first mixed temperature pipeline 71, and a part of the second inflow pipeline 5 in the first temperature mixing unit 7 is referred to as the second mixed temperature pipeline 72, so that the mixed gas smoothly flows in the first inflow pipeline 3 and the second inflow pipeline 5.

The first accommodating chamber 73 is provided with a heat transfer liquid therein, at least a part of the first mixed temperature pipeline 71 is in contact with the heat transfer liquid, and the second mixed temperature pipeline 72 is provided in the first accommodating chamber 73 to exchange heat with the first mixed temperature pipeline 71.

The first mixed-temperature pipeline 71 and the second mixed-temperature pipeline 72 are both in contact with the heat-conducting liquid, and the heat exchange speed of the mixed gas in the first mixed-temperature pipeline 71 and the mixed gas in the second mixed-temperature pipeline 72 can be increased by arranging the heat-conducting liquid. It can be understood that the first accommodating chamber 73 is set at the ambient temperature, the temperature difference between the mixed gas flowing out of the gas mixing structure 100 and the heat-conducting liquid in the first inflow pipeline 3 is small, and the temperature difference between the mixed gas flowing out of the sample pipeline 200 and the heat-conducting liquid in the second inflow pipeline 5 is large, so that at least a part of the first temperature mixing pipeline 71 is in contact with the heat-conducting liquid, the contact area between the first temperature mixing pipeline 71 and the heat-conducting liquid is small, and the second temperature mixing pipeline 72 is disposed in the first accommodating chamber 73 and is in full contact with the heat-conducting liquid, thereby balancing the gas temperature in the first temperature mixing pipeline 71 and the gas temperature in the second temperature mixing pipeline 72.

In some embodiments of the present invention, the heat conducting liquid is a heat conducting oil liquid.

The following description will be made by taking a specific example of measuring the specific surface area of a sample to be measured by a thermal conductivity measuring device using a dynamic nitrogen adsorption method as an example.

The gas mixing structure 100 and the first temperature mixing unit 7 are both arranged at ambient temperature, and the sample pipeline 200 is arranged in the environment of liquid nitrogen (-196 ℃), so the temperature difference between the temperature of the gas mixture flowing out of the gas mixing structure 100 and the heat-conducting oil liquid in the first inflow pipeline 3 is small, the temperature of the gas mixture flowing out of the sample pipeline 200 in the second inflow pipeline 5 is close to minus 196 ℃, the temperature difference between the temperature of the gas mixture flowing out of the sample pipeline 200 in the second inflow pipeline 5 and the heat-conducting oil liquid is large, the second temperature mixing pipeline 72 is arranged in the first accommodating cavity 73 and is in full contact with the heat-conducting oil liquid, and the heat exchange efficiency is improved.

In some embodiments of the present invention, as shown in fig. 2, the first mixed temperature pipeline 71 includes: a first housing 75 and a second housing 76, the first housing 75 defining a first accommodating chamber 73 therein, the second housing 76 being disposed outside the first housing 75 and spaced apart from the first housing 75, the second housing 76 defining a second accommodating chamber 74 with the first housing 75 for flowing the mixture, the first temperature mixing pipe 71 not being a general shaft-shaped pipe but a revolution-shaped pipe formed by the first housing 75 and the second housing 76 together, the first housing 75 and the second housing 76 defining the second accommodating chamber 74 of the revolution-shaped pipe, and the mixture flowing in the second accommodating chamber 74. As shown in fig. 2, the air inlet of the first temperature mixing pipeline 71 is disposed at one end of the second accommodating cavity 74, the air outlet of the first temperature mixing pipeline 71 is disposed at the other end of the second accommodating cavity 74, and when the mixed gas flowing from the gas mixing structure 100 to the reference arm 1 enters the first temperature mixing pipeline 71, part of the mixed gas circulates in the second accommodating cavity 74 for more than one circle along with the revolving pipeline, so that the mixed gas fully contacts with the outer surface of the first housing 75, and compared with a common shaft-shaped pipe, the heat exchange effect of the mixed gas can be improved. The first accommodating cavity 73 is formed in the first temperature mixing pipeline 71, the second accommodating cavity 74 is arranged on the periphery of the first accommodating cavity 73, and the mixed gas in the first temperature mixing pipeline 71 and the heat-conducting liquid in the first accommodating cavity 73 exchange heat through the first shell 75.

In some embodiments of the present invention, as shown in fig. 2, the first housing 75 is configured as a rectangle, the second housing 76 is also configured as a rectangle, the first accommodating chamber 73 is configured as a rectangle accommodating chamber, and the projection plane of the second accommodating chamber 74 is configured as a "return" structure.

In other embodiments of the present invention, the first casing 75 is an ellipsoid, the second casing 76 is an ellipsoid, and the second projection surface of the accommodating chamber 74 is an ellipse, so that the turbulent flow of the mixture in the pipeline can be reduced, the smooth flow of the mixture in the first mixed temperature pipeline 71 can be realized, and the heat exchange effect can be improved.

In some embodiments of the present invention, the second mixed temperature pipeline 72 includes: main pipe 721 and branch pipes 722, the branch pipes 722 being plural and provided on the peripheral wall of main pipe 721, both ends of each branch pipe 722 communicating with main pipe 721.

The second mixed temperature pipeline 72 is provided with a plurality of branch pipelines 722, and the branch pipelines 722 extend towards the direction far away from the main pipeline 721, and then are connected with the main pipeline 721, compare in ordinary axle venturi tube, and the second mixed temperature pipeline 72 increases with the contact surface of heat-conducting liquid, promotes the heat transfer effect.

When the mixed gas flows in the second mixed-temperature pipeline 72, the mixed gas firstly enters the main pipeline 721, then is divided by the plurality of branch pipelines 722, and the mixed gas in the branch pipelines 722 flows back to the main pipeline 721 again after heat exchange to be fully fused, so that the temperature of the mixed gas in the second mixed-temperature pipeline 72 is uniform. And the mixed gas flowing back to main pipeline 721 from branch pipeline 722 can form self-hedging with the mixed gas flowing in main pipeline 721, so that the mixed gas can be more fully merged, the flow speed of the gas flow in main pipeline 721 can be reduced, the heat exchange process is prolonged, and the heat exchange effect is improved. The main pipe 721 is provided with a plurality of branch pipes 722, and the mixed gas undergoes the processes of flow distribution, heat exchange and mixed flow for a plurality of times, so that the mixed gas can be fully contacted with the heat-conducting liquid, and the heat exchange effect is good.

In some embodiments of the present invention, as shown in fig. 2, each branch pipe 722 includes: an inclined tube 722a and a circular arc tube 722b, one end of the inclined tube 722a is connected to the main pipe 721, a distance between a center line of the inclined tube 722a and a center line of the main pipe 721 is gradually increased in a flow direction of the mixture gas in the main pipe 721, and the circular arc tube 722b is connected between the other end of the inclined tube 722a and the main pipe 721.

As shown in fig. 2, one end of the inclined tube 722a is connected to the main pipe 721, the other end of the inclined tube 722a extends in a direction away from the main pipe 721, a distance between a center line of the inclined tube 722a and a center line of the main pipe 721 gradually increases in a flow direction of the mixed gas in the main pipe 721, the flow direction of the air flow in the inclined tube 722a is the same as the flow direction of the air flow in the main pipe 721, fluency of the air flow flowing from the main pipe 721 to the branch pipe 722 is improved, and the circular arc tube 722b is connected between the other end of the inclined tube 722a and the main pipe 721. The mixed gas flows in the main pipe 721 firstly, then is divided by the plurality of inclined pipes 722a, flows into the mixed gas of the inclined pipes 722a, exchanges heat with the heat-conducting liquid through the inclined pipes 722a and the circular arc pipes 722b, and then flows back to the main pipe 721 again to be fully fused, so that the temperature of the mixed gas in the second mixed temperature pipeline 72 is uniform. The inclined tube 722a and the arc tube 722b can increase the contact area, and the heat-conducting liquid flowing through the second mixed-temperature pipeline 72 can form a vortex, so as to further improve the heat exchange effect. Compared with a linear pipeline, the structure of the arc pipe 722b enables the mixed gas to flow smoothly in the pipeline, the occurrence of airflow turbulence is reduced, the airflow speed of the mixed gas in the arc pipe 722b is high, the self-hedging effect of the mixed gas flowing back to the main pipeline 721 from the branch pipeline 722 and the mixed gas flowing in the main pipeline 721 is good, the mixed gas can be fused more sufficiently, the airflow flowing speed in the main pipeline 721 is reduced, and the heat exchange effect is further improved.

In some embodiments of the present invention, the included angle α between the chute 722a and the main pipe 721 satisfies: alpha is more than or equal to 15 degrees and less than or equal to 30 degrees.

The included angle between the inclined tube 722a and the main pipeline 721 is too large, so that the mixed gas is not easily shunted by the branch pipeline 722, the heat exchange efficiency of the mixed gas is reduced, the included angle between the inclined tube 722a and the main pipeline 721 is too small, the contact area between the heat-conducting liquid and the second mixed-temperature pipeline 72 is reduced, and the heat exchange efficiency of the mixed gas is also reduced, the included angle alpha between the inclined tube 722a and the main pipeline 721 is set within the range of 15-30 degrees, the mixed gas can be effectively ensured to flow into the branch pipeline 722, the contact area between the branch pipeline 722 and the heat-conducting liquid is larger, and the heat exchange efficiency is higher.

Preferably, the angle α between the chute 722a and the main conduit 721 is 20 °.

In some embodiments of the present invention, the included angle between the flow direction of the mixture in the portion where the circular arc tube 722b is connected to the main pipe 721 and the flow direction of the mixture in the main pipe 721 is 120 ° -165 °, so that the mixture flowing back to the main pipe 721 from the branch pipe 722 and the mixture flowing in the main pipe 721 form a good self-hedging effect, which can make the mixture fuse more fully, slow down the flow speed of the air flow in the main pipe 721, and further improve the heat exchange effect.

Preferably, an angle between a flow direction of the mixture gas in the portion of the circular arc pipe 722b connected to the main pipe 721 and the flow direction of the mixture gas in the main pipe 721 is 135 °.

In some embodiments of the present invention, the second temperature mixing unit 8 includes: a third housing 81, a third mixed temperature pipeline 83 and a fourth mixed temperature pipeline 84, wherein a third accommodating cavity 82 is formed inside the third housing 81, a heat conducting liquid is accommodated inside the third accommodating cavity 82, the third mixed temperature pipeline 83 is configured as a part of the first inflow pipeline 3 and is arranged in the third accommodating cavity 82, and the fourth mixed temperature pipeline 84 is configured as a part of the second inflow pipeline 5 and is arranged in the third accommodating cavity 82.

The third mixed temperature pipeline 83 is configured as a part of the first inflow pipeline 3, and the fourth mixed temperature pipeline 84 is configured as a part of the second inflow pipeline 5, for convenience of description only, so that a part of the first inflow pipeline 3 located in the second temperature mixing unit 8 is referred to as the third mixed temperature pipeline 83, and a part of the second inflow pipeline 5 located in the second temperature mixing unit 8 is referred to as the fourth mixed temperature pipeline 84.

The third holds and is provided with the heat-conducting liquid in the chamber 82, and the third mixes warm pipeline 83 and the fourth and mixes warm pipeline 84 and all sets up in the third holds chamber 82, and the third mixes warm pipeline 83 and the fourth and mixes warm pipeline 84 and all contacts with the heat-conducting liquid, and the gas mixture of the third and the mixed warm pipeline 83 and the gas mixture accessible heat-conducting liquid in the fourth mixed warm pipeline 84 carry out the heat exchange.

The second temperature mixing unit 8 is spaced apart from the first temperature mixing unit 7, and the second temperature mixing unit 8 is disposed on one side of the first temperature mixing unit 7 close to the thermal conductivity cell 300, so that the mixture flowing through the first temperature mixing pipeline 71 then flows into the third temperature mixing pipeline 83, and the mixture flowing through the second temperature mixing pipeline 72 then flows into the fourth temperature mixing pipeline 84, so that the temperature difference between the mixture in the third temperature mixing pipeline 83 and the mixture in the fourth temperature mixing pipeline 84 is small, and the heat exchange requirement can be satisfied by disposing both the third temperature mixing pipeline 83 and the fourth temperature mixing pipeline 84 in the third accommodating cavity 82, so that the temperature of the mixture flowing out of the third temperature mixing pipeline 83 is close to the temperature of the mixture flowing out of the fourth temperature mixing pipeline 84.

In some embodiments of the present invention, the third mixed temperature pipeline 83 and the fourth mixed temperature pipeline 84 are both constructed as a spiral pipe, and the third mixed temperature pipeline 83 and the fourth mixed temperature pipeline 84 are alternately wound to increase the contact area between the mixed gas and the heat conducting liquid and increase the heat exchange effect.

The present invention describes the embodiment with two temperature mixing units 400, which is only for illustrative purposes, but it is obvious to those skilled in the art after reading the above technical solutions that the technical solutions of three or more temperature mixing units 400 can be applied to the present invention, and this also falls into the protection scope of the present invention.

In the description of the present invention, it is to be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", and the like, indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for convenience of description and simplicity of description, and do not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore, should not be construed as limiting the present invention.

In the description of the present invention, "the first feature" and "the second feature" may include one or more of the features.

In the description of the present invention, "a plurality" means two or more.

Other configurations of the thermal conductivity detection apparatus according to embodiments of the present invention, such as gas mixing structures and sample lines, etc., and operations are known to those of ordinary skill in the art and will not be described in detail herein.

In the description herein, references to the description of the term "one embodiment," "some embodiments," "an illustrative embodiment," "an example," "a specific example," or "some examples" or the like mean that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the terms used above do not necessarily refer to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

While embodiments of the present invention have been shown and described, it will be understood by those of ordinary skill in the art that: various changes, modifications, substitutions and alterations can be made to the embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the claims and their equivalents.

Claims

1. A thermal conductivity detection device, comprising:

the gas mixing structure is provided with a gas mixing output end for leading out mixed gas;

the device comprises a sample pipeline, a sample to be detected and a control circuit, wherein a sample to be detected is placed in the sample pipeline;

the thermal conductivity cell comprises a reference arm and a measuring arm, a first inflow pipeline is connected between an inflow end of the reference arm and the gas mixing output end, a first outflow pipeline is connected between an outflow end of the reference arm and one end of the sample pipeline, and a second inflow pipeline is connected between the other end of the sample pipeline and an inflow end of the measuring arm;

and the temperature mixing unit is internally provided with a heat exchange space, and at least part of the first inflow pipeline and at least part of the second inflow pipeline are positioned in the heat exchange space so as to exchange heat between the mixed gas flowing to the reference arm and the mixed gas flowing to the measuring arm.

2. The thermal conductivity detection device according to claim 1, wherein the temperature mixing unit is configured in plurality, and the plurality of temperature mixing units are spaced apart in a gas flow direction of the first inflow piping or in a gas flow direction of the second inflow piping.

3. The thermal conductivity detection device of claim 2, wherein the plurality of temperature mixing units comprise: a first temperature mixing unit comprising:

the heat conduction liquid is arranged in the first accommodating cavity;

a first mixed temperature pipeline configured as a portion of the first inflow pipeline, at least a portion of the first mixed temperature pipeline being in contact with the thermally conductive liquid;

a second mixed temperature pipeline configured as a part of the second inflow pipeline, the second mixed temperature pipeline being disposed in the first accommodation chamber to exchange heat with the first mixed temperature pipeline.

4. The thermal conductivity detection device of claim 3, wherein the first temperature mixing pipeline comprises:

a first housing defining the first receiving chamber therein;

the second shell is arranged on the outer side of the first shell and is spaced from the first shell, and the second shell and the first shell define a second containing cavity for mixed gas to flow.

5. The thermal conductivity detection device of claim 3, wherein the second temperature mixing pipeline comprises: the branch pipelines are multiple and arranged on the peripheral wall of the main pipeline, and two ends of each branch pipeline are communicated with the main pipeline.

6. The thermal conductivity detection device of claim 5, wherein each of the branch pipes comprises: the device comprises an inclined pipe and an arc pipe, wherein one end of the inclined pipe is connected with the main pipeline, the distance between the central line of the inclined pipe and the central line of the main pipeline is gradually increased in the flowing direction of mixed gas in the main pipeline, and the arc pipe is connected between the other end of the inclined pipe and the main pipeline.

7. The thermal conductivity detection device of claim 6, wherein an angle α between the inclined tube and the main conduit satisfies: alpha is more than or equal to 15 degrees and less than or equal to 30 degrees.

8. The thermal conductivity detection device of claim 6, wherein an included angle between a flow direction of the mixture in the circular arc tube and the main pipeline connecting portion and a flow direction of the mixture in the main pipeline is 120-165 °.

9. The thermal conductivity detection device of claim 3, wherein the temperature mixing unit further comprises: a second temperature mixing unit disposed at one side of the first temperature mixing unit close to the thermal conductivity cell, the second temperature mixing unit including:

a third housing, in which a third accommodating chamber is formed, and heat conducting liquid is accommodated in the third accommodating chamber;

a third mixed temperature pipeline configured as a part of the first inflow pipeline and disposed in the third accommodation chamber;

a fourth mixed temperature pipeline configured as a portion of the second inflow pipeline and disposed in the third receiving cavity.

10. The thermal conductivity detection device of claim 9, wherein the third and fourth mixed temperature pipelines are each configured as a helical coil, the third and fourth mixed temperature pipelines being alternately wound.