CN211528138U - Temperature control device of liquid phase diffusion coefficient measuring instrument - Google Patents

Temperature control device of liquid phase diffusion coefficient measuring instrument Download PDF

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CN211528138U
CN211528138U CN201921949626.1U CN201921949626U CN211528138U CN 211528138 U CN211528138 U CN 211528138U CN 201921949626 U CN201921949626 U CN 201921949626U CN 211528138 U CN211528138 U CN 211528138U
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temperature control
temperature
diffusion coefficient
liquid phase
phase diffusion
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孟伟东
曹新飞
普小云
魏利
丹丽智
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Yunnan University YNU
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Abstract

The utility model discloses a temperature control device of liquid phase diffusion coefficient measuring apparatu, including measuring the box, be provided with heating and refrigerating plant in the measurement box, measure the box and be provided with temperature-detecting device, temperature-detecting device signal connection has temperature control system, and temperature control system passes through the cable and is connected with the heating and refrigerating plant electricity. The measuring box body comprises a heat preservation box body, and a light perspective window is arranged on the side surface of the heat preservation box body; the inner wall of the light perspective window arranged on the heat preservation box body is provided with a liquid core column lens. By arranging the device, the temperature control device of the liquid phase diffusion coefficient measuring instrument can realize accurate temperature control within the range of 5-50 ℃, the temperature control precision is +/-0.05 ℃, and the device has the characteristics of small volume, low price, high temperature rise and drop speed and simplicity in operation.

Description

Temperature control device of liquid phase diffusion coefficient measuring instrument
Technical Field
The utility model relates to a liquid phase diffusion coefficient measures the field, especially relates to a temperature control device of liquid phase diffusion coefficient measuring apparatu.
Background
The liquid phase diffusion coefficient is important basic data for researching mass transfer process, calculating mass transfer rate and chemical design and development, and is widely applied to new industries such as biology, chemical engineering, medicine, environmental protection and the like. The diffusion coefficients of various substances, especially the diffusion coefficients under different temperature conditions, are very poor. At present, the liquid phase diffusion coefficient is mainly obtained by an experimental method, and is calculated according to Fick's law describing the diffusion process by measuring the distribution of the concentration of a solution formed in the diffusion process along with space and time.
Among them, the membrane cell method (Stoke R.H., An imaged diaphragm-cell for Diffusion students, and the society tests of the method, J.Am.chem.Soc.,72:763-767(1950)), the interference method of light (Zhao Chang Wei, Liun, Malibusheng, summer Qian, Measurement of Liquid Difference Coefficientso Aqueous Solutions of Glycine, L-Alanine, L-valve and L-isoleucin by Holograhic interaction, Chinese Journal of Chemical Engineering,13(2):285-290(2005)) and the "Taylor method" (Cottet H., Bilon J.P., Martin M, Taylor analysis, 2007-73) are three methods of Measurement.
The three traditional methods have the problems of complex device, insufficient stability, poor result precision and the like. In order to solve the problems of the traditional method, a Double-liquid core column lens with high refractive index measurement capability and adjustable system spherical aberration is designed, the invention patent ZL201610436334.2[ P ] in China, which is an invention of an aplanatic variable-focus Double-liquid core column lens (Przewale, Bangweast, Xiyan, Song Farling) for measuring liquid phase diffusion coefficient, and an academic paper of Double-liquid-core cylindrical lens adopted reliable diffusion coefficient (Optics Express,25(5):5626,2017) is published. Three methods for measuring the liquid phase diffusion coefficient based on a liquid core column lens focal plane imaging method are provided: "method and apparatus for measuring liquid phase diffusion coefficient" (Liqiang, Puchouyun, Sunlelicun, Li yu), Chinese invention patent ZL201110283339.3[ P ], and published academic papers on "method for measuring liquid phase diffusion coefficient by capillary imaging — Isorefractive index thin layer measurement" (Physics, 62(9):094206, 2013).
In order to improve the resolution of liquid refractive index measurement and reduce the spherical aberration of system imaging, the invention discloses a method for accurately measuring the liquid refractive index and the liquid phase diffusion coefficient based on an Asymmetric liquid core column lens (Sunlie, Puchong, Bangweast, Liqiang), Chinese patent No. 201310412166.X [ P ], and published an academic paper of "Asymmetric liquid-conjugated lens used to measure liquid diffusion coefficient" (applied optics,55(8):2011-2017,2016); the invention discloses a method for rapidly measuring liquid phase diffusion coefficient based on observation height of liquid core column lens and the like (Mega-Dong, Puclout, Xiyan, Chenyan), Chinese patent ZL201611181307.1[ P ], which can calculate diffusion coefficient by observing image change condition at a fixed position, and discloses an academic paper of a method for measuring liquid phase diffusion coefficient based on double liquid core column lens and the like (Chinese optics, 38(1):0112002-1-7,2018).
In order to shorten the measurement time and improve the measurement efficiency, we invented a method for rapidly measuring the liquid phase diffusion coefficient which does not change with the concentration by only using one diffusion image, namely a method for measuring the liquid phase diffusion coefficient by using the instantaneous refractive index spatial distribution of a liquid core cylindrical lens (Zhai Zhang, Puyun, Sunliu, Yanrefin), Chinese patent 201410440938.5[ P ], and published the academic papers of "New method to medium liquid diffusion by analysing and insulating gases diffusion image" (Optics Express, 2015, 23(18), 23155-23166).
The three new methods are obviously improved compared with the traditional method, but no matter which method is used for measuring the liquid phase diffusion coefficients at different temperatures, the experimental conditions need to be adjusted to reach the required experimental temperature, and the air conditioner is adopted in the current laboratory for adjusting the temperature. When the air conditioner is used for temperature adjustment, the following defects can exist:
1) the temperature adjusting range of the air conditioner is limited, and is generally between 15 and 40 ℃;
2) the temperature control of the air conditioner is not accurate enough, and the error is +/-1 ℃;
3) when the air conditioner is used for adjusting the room temperature, the heat preservation treatment needs to be carried out on a laboratory, the corresponding experiment temperature is ensured in the whole experiment space, the control is relatively difficult, and the experiment cost is high;
4) when the air conditioner is used for adjusting the temperature of a laboratory, high-temperature experiments are carried out, and experimenters are difficult to carry out experiments for a long time;
5) the air conditioner is large in size and power, and a large amount of electric energy is consumed to control the temperature by using the air conditioner, so that resource waste is caused.
SUMMERY OF THE UTILITY MODEL
The invention of the utility model aims to: aiming at the existing problems, the temperature control device and the temperature control method of the liquid phase diffusion coefficient measuring instrument are provided, the problem that the temperature control range of the traditional air conditioner is limited is solved, the problem that the temperature control precision of the traditional air conditioner is low is solved, and the problem that the corresponding speed of the temperature control of the traditional air conditioner is low is solved. The problem that the whole temperature change is not beneficial to the operation of workers is solved. The problem of high temperature control energy consumption is solved. The temperature control system utilizes a semiconductor refrigeration chip and a TCM series digital temperature control module to design a temperature control method and a temperature control device for a liquid phase diffusion coefficient instrument by combining a PID algorithm. The temperature control device of the liquid phase diffusion coefficient measuring instrument can realize accurate temperature control within the range of 5-50 ℃, and the temperature control precision is +/-0.05 ℃; and has the characteristics of small volume, low price, high temperature rise and fall speed, simple operation and the like.
The utility model adopts the technical scheme as follows:
the temperature control device of the liquid phase diffusion coefficient measuring instrument comprises a measuring box body, wherein a heating and refrigerating device is arranged in the measuring box body, a temperature detection device is arranged in the measuring box body, the temperature detection device is in signal connection with a temperature control system, and the temperature control system is electrically connected with the heating and refrigerating device through a cable.
Furthermore, the invention also discloses a preferable structure of the temperature control device of the liquid phase diffusion coefficient measuring instrument, wherein the measuring box body comprises a heat preservation box body, and a light ray perspective window is arranged on the side surface of the heat preservation box body; the inner wall of the light perspective window arranged on the heat preservation box body is provided with a liquid core column lens.
Furthermore, the heating and refrigerating device comprises a plurality of semiconductor refrigerating pieces, and a heat conduction device is arranged on the outer sides of the semiconductor refrigerating pieces; and a heat conduction device is arranged between the semiconductor refrigeration sheet and the liquid core cylindrical lens.
Furthermore, the temperature detection device is a temperature sensor, and the temperature sensor is connected with the temperature control system through a cable.
Further, the heat conduction device is a heat sink; the radiating fin is connected with the semiconductor refrigerating fin through a heat conducting material; and the radiating fins are provided with radiating fans.
Furthermore, the temperature control system comprises a TCM digital temperature control module, and the TCM digital temperature control module is connected with a computer control system through a cable.
Furthermore, the temperature sensor is in signal connection with the TCM digital temperature control module through a signal output line, and the semiconductor refrigeration piece is electrically connected with the TCM digital temperature control module through a semiconductor refrigeration piece current input line.
Furthermore, the TCM digital temperature control module comprises a PID controller which controls and drives the semiconductor refrigerating sheet by adjusting voltage; the PID controller consists of a proportional unit P, an integral unit I and a differential unit D.
Furthermore, a PID parameter automatic setting module is arranged in the PID controller, and comprises a proportional coefficient Kp automatic setting module, an integral time constant Ti automatic setting module and a differential time constant Td automatic setting module.
To sum up, owing to adopted above-mentioned technical scheme, the beneficial effects of the utility model are that:
1. by arranging the device, the temperature control device of the liquid phase diffusion coefficient measuring instrument can realize accurate temperature control within the range of 5-50 ℃, the temperature control precision is +/-0.05 ℃, and the device has the characteristics of small volume, low price, high temperature rise and drop speed and simplicity in operation.
2. The liquid core column lens and the temperature control device which are required to control the temperature of the measuring instrument are placed in the heat preservation box, so that the size is reduced, and the price is lowered. The heat preservation box body can not only improve the temperature rise and fall speed, but also reduce the fluctuation of temperature.
3. The semiconductor refrigerating sheet and the TCM digital temperature control module are used, so that the price can be reduced, and the temperature rise and fall speed can be increased. The semiconductor refrigerating chip and the TCM digital temperature control module are combined with the PID algorithm to realize very simple temperature control operation and high temperature control precision.
Drawings
FIG. 1 is a schematic structural diagram of a temperature control device of a liquid phase diffusion coefficient measuring system according to the present invention;
fig. 2 is a perspective view of a temperature control device for a liquid phase diffusion coefficient measuring instrument based on a liquid core column lens used in the present invention;
fig. 3 is a top view of the temperature control device based on the liquid-core column lens liquid phase diffusion coefficient measuring instrument used in the present invention;
FIG. 4 is a front view of a temperature control device for a liquid-core column lens based liquid-phase diffusion coefficient measuring instrument;
FIG. 5 is a graph showing the effect of temperature control when the temperature is set at 10 ℃;
FIG. 6 is a graph showing the effect of temperature control at a temperature set at 20 ℃;
FIG. 7 shows the effect of temperature control at a temperature set at 30 ℃;
FIG. 8 is a graph showing the effect of temperature control at a temperature set at 40 ℃;
FIG. 9 is a graph showing the effect of temperature control at a temperature set at 50 ℃;
FIG. 10 is a graph of the diffusion of aqueous beta-alanine in water at 1200 s; (a) 15 ℃ below zero; (b) the method comprises the following steps 30 ℃; (c) the method comprises the following steps At 45 ℃.
FIG. 11 is a graph of the diffusion of aqueous beta-alanine in water at 2400 s; (a) 15 ℃ below zero; (b) the method comprises the following steps 30 ℃; (c) the method comprises the following steps At 45 ℃.
FIG. 12 is a diffusion image of aqueous beta-alanine solution in water at 3600 s; (a) 15 ℃ below zero; (b) the method comprises the following steps 30 ℃; (c) the method comprises the following steps At 45 ℃.
The labels in the figure are: the device comprises a heat preservation box body 1, a light perspective window 2, a liquid core column lens 3, a semiconductor refrigeration sheet 4, a signal input line 5, a signal output line 6, a temperature sensor 7, a TCM-digital temperature control module 8, a computer control system 9, a heat radiation fin 10, a heat radiation fan 11 and a semiconductor refrigeration sheet current input line 12.
Detailed Description
The present invention will be described in detail with reference to the accompanying drawings.
In order to make the objects, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.
As shown in figures 1-4, the invention discloses a temperature control device of a liquid phase diffusion coefficient measuring instrument, a liquid core column lens 3 and the temperature control device are arranged in a heat preservation box 1. The width-limited parallel light used in the experiment is incident on the liquid core column lens 3 through the light perspective window 2 and then is imaged on an imaging system through the light perspective window.
The semiconductor refrigerating sheet 4 is used for refrigerating and heating; two semiconductor refrigerating pieces 4 with moderate power are selected for selection of the semiconductor refrigerating pieces 4. Heat-conducting silicone grease is smeared on two surfaces of the semiconductor refrigerating sheet 4, the refrigerating surface is attached to an aluminum alloy heat-conducting block, and the aluminum alloy heat-conducting block is attached to the liquid core column lens 3 in the liquid phase diffusion coefficient measuring system so as to absorb and transfer heat. The hot side is closely attached to the heat sink 10, which dissipates heat and protects the device from damage due to excessive temperatures.
The TCM digital temperature control module 8 controls the operation of the semiconductor refrigerating chip 4 through a signal input line 5. The temperature sensor 7 is transmitted to the TCM digital temperature control module 8 through a signal output line 6. The TCM digital temperature control module 8 controls the semiconductor refrigerating chip 4, and the TCM digital temperature control module 8 simultaneously receives a temperature signal of the temperature sensor 7. And the computer control system 9 controls the TCM digital temperature control module 8 to acquire images acquired by the imaging system.
Behind the heat sink 10, a heat dissipation fan 11 is placed at a fixed position to ensure good heat dissipation. Meanwhile, the fan is not tightly attached to the radiating fins, so that the influence of the vibration of the fan on the liquid diffusion speed is prevented. The position of the heat sink and fan are shown in perspective view in fig. 2 and in top view in fig. 3. Two temperature sensors 7 are arranged at proper positions without influencing the light path and are fed back to the TCM digital temperature control module 8 as the temperature channel 1 and the temperature channel 2 to control the refrigerating and heating power of the semiconductor refrigerating sheet 4.
In the specific operation process, the temperature sensor 7 sends a detected temperature signal to the TCM digital temperature control module 8; the TCM digital temperature control module 8 compares the received temperature signal with a preset signal, and then adjusts the working state and the working power of the semiconductor refrigeration sheet 4 according to the difference value to realize the constant temperature in the heat preservation box body 1.
Further, the TCM digital temperature control module 8 includes a PID controller, and the PID controller controls and drives the semiconductor refrigeration chip 4 by adjusting voltage; the PID controller consists of a proportional unit P, an integral unit I and a differential unit D.
Furthermore, a PID parameter automatic setting module is arranged in the PID controller, and comprises a proportional coefficient Kp automatic setting module, an integral time constant Ti automatic setting module and a differential time constant Td automatic setting module.
The control part of the device adopts a TCM digital temperature control module to control the semiconductor refrigeration piece by combining a temperature sensor and a feedback device to carry out high-precision temperature control. The TCM digital temperature control module internally comprises a PID parameter automatic setting function, wherein PID is a proportional-integral-derivative controller, is a common feedback loop component in industrial control application and consists of a proportional unit P, an integral unit I and a derivative unit D. By adjusting the PID parameters, the output power of the temperature control device can be gradually reduced when the actual temperature approaches the set temperature, and the actual temperature is ensured to gradually approach the set temperature, so that the temperature overshoot is reduced.
The PID parameter automatic setting function is that the temperature control module automatically adjusts the PID parameters according to the current actual system condition. After the temperature controller is started, the temperature controller oscillates according to the vicinity of the set temperature so as to measure the temperature characteristic of the temperature control system, and then 4 appropriate PID parameters are automatically calculated: proportional coefficient, integration time, differentiation time, control interval. Suitable PID parameters allow the actual temperature to float around the set temperature with a small temperature difference.
In practical engineering, the most widely used regulator control law is proportional, integral and derivative control, abbreviated as PID control, also known as PID regulation. A PID controller (proportional-integral-derivative controller) is a common feedback loop component in industrial control applications, consisting of a proportional unit P, an integral unit I and a derivative unit D. The PID controller is widely applied because an accurate system model is not needed. The PID calculation formula is as follows:
Figure BDA0002269407320000081
namely, the output voltage of the temperature controller is equal to the calculation result of the power voltage of the temperature controller multiplied by PID. Therefore, when the power supply voltage changes, the effect of temperature control also changes.
The influence of the PID parameters on the temperature control device is as follows:
the proportional coefficient is increased, the system is correspondingly accelerated, the static error is reduced, but the system oscillation is enhanced, and the stability is deteriorated;
the integration time is increased, the overshoot of the system is reduced, the oscillation is weakened, but the elimination of the static error of the system is slowed down;
the differential time is increased, the overshoot is reduced, the system oscillation is weakened, but the system is more sensitive to noise;
in the control system, there is a corresponding proportional relation between the input and output quantities of the proportional regulator, and when the variation is balanced by the proportional regulation, it can not be restored to the given value, it is called "static difference".
And (4) control principle. And (4) correctly connecting the TCM digital temperature control module with a computer, and entering an operation interface. And adjusting the temperature to the required temperature, wherein the actual temperature is the temperature of the position of the temperature probe. The output setting and state can limit the maximum voltage and the maximum current of the output, thereby limiting the output power. The output condition of the TCM digital temperature control module can be checked in the output setting and the state, and the detection precision of the temperature probe can be set by the sensor setting.
And various numerical values of PID parameters can be changed in the PID setting options, so that the temperature control effect of the TCM digital temperature control module is influenced. In order to facilitate use, an automatic setting function is set in a PID calculation method through software, and a set of appropriate PID parameters can be automatically calculated by the TCM digital temperature control module according to various factors such as set temperature, current environment temperature, output power, single chip microcomputer refrigeration efficiency and the like. At each temperature control point, an automatic integral point option in a PID calculation method is selected, and the TCM digital temperature control module can automatically calculate the proportional coefficient of the PID, the integral time of the PID and the differential time of the PID. And when the automatic setting is finished, the accurate temperature control is started.
The parameters of maximum voltage, current, temperature and the like can be set for overvoltage protection, overcurrent protection and over-temperature protection. And when the parameter of the temperature control device is higher than the preset parameter, the default is a dangerous condition, and the TCM digital temperature control module stops working.
A temperature control method of a temperature control device of a liquid phase diffusion coefficient measuring instrument comprises the following steps:
1. a preset voltage value r (t) is input through an input device, the actual voltage fed back by the temperature sensor 7 is received by the TCM digital temperature control module 8 and is c (t), and the TCM digital temperature control module 8 calculates a deviation value e (t) which is r (t) -c (t);
the TCM digital temperature control module 8 calculates the output voltage loaded on the semiconductor refrigerating chip 4, and the calculation formula is as follows:
Figure BDA0002269407320000101
wherein VoutIs the output voltage for driving the semiconductor refrigerating chip 4;
wherein Vin refers to the input voltage of the TCM digital temperature control module 8;
kp is a proportionality coefficient, Ti is an integral time constant, and Td is a differential time constant;
3. in the operation process, the PID parameter automatic setting module adjusts the output characteristic of the PID controller through a proportional coefficient Kp automatic setting module, an integral time constant Ti automatic setting module and a differential time constant Td automatic setting module.
Example 1:
as shown in fig. 5-9, the temperature control method and apparatus of the liquid phase diffusion coefficient measurement system heats the temperature control test.
After the TCM digital temperature control module is connected to the computer correctly, the set temperature, for example 50 ℃, is set by the control software, and the temperature probe is placed on one side of the liquid in the stem lens, and the selection of the position is verified by experiments, wherein the temperature difference between the position and the liquid to be measured is +/-0.05 ℃.
The TCM digital temperature control module is set to be automatically set, a heating mode is output, the output power is high, the temperature rising speed is high, and when the temperature reaches 50 ℃ which is set, the output power is gradually reduced to zero. And then the temperature is slowly increased due to the waste heat of the radiating fins, the output power is rapidly increased after the temperature is gradually reduced after the waste heat is dissipated and is reduced to the set temperature of 50 ℃, so that the temperature is increased for the second time, and the setting is carried out for the third time. And the automatic setting is finished by 100 percent. The TCM digital temperature control module automatically enters a position mode and closes output. PID data obtained by automatic setting are as follows: the PID has a proportionality coefficient of 0.252, PID integration time of 315.71, PID differentiation time of 78.93, and PID control interval of 789 milliseconds, and stores PID parameters.
The TCM digital temperature control module enters a position mode, a heating mode is adopted, output is started, the output power is gradually increased from zero, if the difference between the actual temperature and the set temperature is large, the output power of the TCM digital temperature control module is increased to the maximum output value, the temperature is rapidly increased, and when the temperature is close to the set temperature, the output power is gradually reduced. After the actual temperature gradually reaches the set temperature, the output power gradually stabilizes to a certain value, and finally the actual temperature and the set temperature are overlapped. At the moment, the output power of the TCM digital temperature control module is stable, so that the heat transfer of the heated liquid reaches dynamic balance, and the actual temperature keeps a set value of 50 ℃ stable.
Example 2:
as shown in fig. 5-9, the temperature control method and apparatus of the liquid phase diffusion coefficient measurement system performs a refrigeration temperature control test. After the temperature control device and the computer are correctly connected, the set temperature is set through control software, for example, 5 ℃, and then the automatic setting function is started.
The set temperature is 5 ℃, the output of the TCM digital temperature control module enters a refrigeration mode, and the PID automatic setting function is performed. The temperature is rapidly reduced, when the temperature reaches a set value, the temperature fluctuates for three times near the secondary temperature, and the automatic setting is finished by 100 percent. After the automatic setting function is finished, the obtained PID parameters are as follows: PID has a proportionality coefficient of 0.081, PID has an integration time of 602.36, PID has a differentiation time of 150.59, and PID control interval is 1505 milliseconds. Because the set temperatures are different, the PID parameters obtained after the automatic setting are different. The PID parameter is used for controlling other temperatures, and the other temperatures are found to have low stability and have a temperature fluctuation range of +/-0.2 ℃. Therefore, when the temperature is required to be accurately controlled, PID automatic setting is required to be carried out when different temperatures are set.
After the TCM digital temperature control module enters a position PID calculation mode, the output power is intelligently adjusted by the TCM digital temperature control module. The closer the actual measured temperature is to the set temperature, the output power is gradually reduced to a certain value, the temperature is prevented from being continuously reduced, the output power is gradually stabilized, and finally the actual temperature is overlapped with the set temperature. The output power is kept stable, and the actual temperature is kept stable at a set value of 5 ℃.
Setting different temperatures, and when the difference between the set temperature and the actual temperature is found to be large, the output power efficiency will be reduced, and the time required for temperature rise and temperature reduction is increased. Therefore, in the experiment, when a large temperature difference exists, the output is firstly turned on for preheating treatment, so that the time for reaching the set temperature in the experiment is shortened.
Example 3:
as shown in fig. 10 to 12, the liquid phase diffusion coefficient was measured at different temperatures. In this embodiment, the infinite dilution diffusion coefficients of beta-alanine aqueous solutions with different temperatures are taken as an example to test the temperature control method and the device of the liquid phase diffusion coefficient measurement system.
And connecting a temperature control device, setting the temperature to be measured, automatically setting the temperature, setting and storing the PID parameters. After the setting is finished, the temperature control device is automatically adjusted to a set position, water liquid is injected into the diffusion pool, the temperature device is started to output, the diffusion pool is cooled or heated to a set temperature, the temperature is stabilized at a set value for 15-20 minutes, and calibration is carried out. Cleaning the diffusion cell, injecting 5mol/L beta-alanine aqueous solution below the diffusion cell, standing for a period of time, preheating to stabilize the temperature at a set value for 5 minutes, injecting the above aqueous solution by using a syringe pump, and starting timing. The temperature control method and apparatus were tested using the literature values for the diffusion coefficient of an aqueous solution of beta-alanine at infinite dilution in the range of 15-45 deg.C. The temperature test results are shown in fig. 11.
Experiments were conducted at a temperature range of 15-45 ℃ to measure the infinite dilution diffusion coefficient of aqueous beta-alanine solutions. The temperature is controlled within 3-5 minutes (the temperature control precision is 0.05 ℃) from the beginning of timing the solution above the injection to the temperature stabilization.
FIGS. 10 to 12 show three temperatures of 15 ℃, 30 ℃ and 45 ℃ as examples of different temperatures. Transient diffusion images were taken at 1200s, 2400s, and 3600s when the infinite dilution diffusion coefficient of the β -alanine aqueous solution was measured.
As diffusion proceeds, the "waist" of the diffusion image at different temperatures drifts at different rates. The results of the experiment show that the infinite dilution diffusion coefficients of different temperatures of the beta-alanine aqueous solution are shown in the following table.
As shown in the table below, the temperature control device controls the liquid phase diffusion coefficient measuring instrument, and the experimental value of the diffusion coefficient of the beta-alanine aqueous solution infinitely diluted at 15 ℃,20 ℃,25 ℃, 30 ℃, 35 ℃, 40 ℃, 45 ℃ and 7 temperatures is very close to the literature value, thereby proving the feasibility of the experimental method and the stability of the temperature control device. The temperature control reliability of the temperature control device is verified by the temperature test result and the liquid phase diffusion coefficient experiment result.
Figure BDA0002269407320000131
As shown in the table, the temperature control device controls the liquid phase diffusion coefficient measuring instrument, and the experimental value of the diffusion coefficient of the beta-alanine aqueous solution infinitely diluted at 15 ℃,20 ℃,25 ℃, 30 ℃, 35 ℃, 40 ℃, 45 ℃ and 7 temperatures is very close to the literature value, thereby proving the feasibility of the experimental method and the stability of the temperature control device. The temperature control reliability of the temperature control device is verified by the temperature test result and the liquid phase diffusion coefficient experiment result.
By arranging the device, the temperature control device of the liquid phase diffusion coefficient measuring instrument can realize accurate temperature control within the range of 5-50 ℃, the temperature control precision is +/-0.05 ℃, and the device has the characteristics of small volume, low price, high temperature rise and drop speed and simplicity in operation. The liquid core column lens and the temperature control device which are required to control the temperature of the measuring instrument are placed in the heat preservation box, so that the size is reduced, and the price is lowered. The heat preservation box body can not only improve the temperature rise and fall speed, but also reduce the fluctuation of temperature. The semiconductor refrigerating sheet and the TCM digital temperature control module are used, so that the price can be reduced, and the temperature rise and fall speed can be increased. The semiconductor refrigerating chip and the TCM digital temperature control module are combined with the PID algorithm to realize very simple temperature control operation and high temperature control precision.
The above description is only exemplary of the present invention and should not be taken as limiting the scope of the present invention, as any modifications, equivalents, improvements and the like made within the spirit and principles of the present invention are intended to be included within the scope of the present invention.

Claims (7)

1. A temperature control device of a liquid phase diffusion coefficient measuring instrument is characterized in that: the temperature measurement device is connected with a temperature control system through a signal, and the temperature control system is electrically connected with the heating and refrigerating device through a cable.
2. The temperature control device of a liquid phase diffusion coefficient measuring instrument as claimed in claim 1, wherein: the measuring box body comprises a heat preservation box body (1), and a light perspective window (2) is arranged on the side surface of the heat preservation box body (1); the inner wall of the light perspective window (2) arranged on the heat preservation box body (1) is provided with a liquid core column lens (3).
3. The temperature control device of a liquid phase diffusion coefficient measuring instrument as claimed in claim 2, wherein: the heating and refrigerating device comprises a plurality of semiconductor refrigerating pieces (4), and a heat conduction device is arranged on the outer side of each semiconductor refrigerating piece (4); and a heat conduction device is arranged between the semiconductor refrigeration sheet (4) and the liquid core column lens (3).
4. A temperature control device of a liquid phase diffusion coefficient measuring instrument as claimed in claim 3, wherein: the temperature detection device is a temperature sensor (7), and the temperature sensor (7) is connected with the temperature control system through a cable.
5. The temperature control device of a liquid phase diffusion coefficient measuring instrument according to claim 4, wherein: the heat conduction device is a heat sink (10); the radiating fin (10) is connected with the semiconductor refrigerating fin (4) through a heat conducting material; the radiating fins (10) are provided with radiating fans (11).
6. The temperature control device of a liquid phase diffusion coefficient measuring instrument according to claim 5, wherein: the temperature control system comprises a TCM digital temperature control module (8), and the TCM digital temperature control module (8) is connected with a computer control system (9) through a cable.
7. The temperature control device of a liquid phase diffusion coefficient measuring instrument according to claim 6, wherein: the temperature sensor (7) is in signal connection with the TCM digital temperature control module (8) through a signal output line (6), and the semiconductor chilling plate (4) is electrically connected with the TCM digital temperature control module (8) through a semiconductor chilling plate current input line (12).
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Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN110736683A (en) * 2019-11-12 2020-01-31 云南大学 Temperature control device and method for liquid phase diffusion coefficient measuring instruments
CN116219665A (en) * 2023-02-09 2023-06-06 青岛富润达纺织有限公司 Dye liquor process temperature following control method based on temperature speed adjustment
CN110736683B (en) * 2019-11-12 2024-10-29 云南大学 Temperature control device and method for liquid phase diffusion coefficient measuring instrument

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN110736683A (en) * 2019-11-12 2020-01-31 云南大学 Temperature control device and method for liquid phase diffusion coefficient measuring instruments
CN110736683B (en) * 2019-11-12 2024-10-29 云南大学 Temperature control device and method for liquid phase diffusion coefficient measuring instrument
CN116219665A (en) * 2023-02-09 2023-06-06 青岛富润达纺织有限公司 Dye liquor process temperature following control method based on temperature speed adjustment

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