Temperature prediction method and device for column oven of ion chromatograph

Abstract

The invention belongs to the field of ion chromatography, and particularly relates to a temperature prediction method and device for an ion chromatograph column oven, and the method comprises the steps: firstly constructing a temperature change model based on the Newton's cooling law; after a heat source in the column oven begins to heat, three time points t1, t2 and t3 are selected, t3-t2 is made to be equal to t2-t1, cavity temperatures T1, T2 and T3 corresponding to temperature sensors in the column oven at the three moments are recorded, and temperature models corresponding to the moments are built; logarithms of the model formulas of the cavity temperature values T1, T2 and T3 at the three moments t1, t2 and t3 are taken and calculated to obtain a prediction model of the final cavity temperature value T; and calculating and comparing the final temperature value T final value of the cavity with the required temperature value T required of the cavity, and adjusting the temperature T heat source of the heat source in advance. According to the method, the waiting time after each adjustment is reduced, the time required by the temperature control system is shortened, the response speed of the system is improved, the energy consumption can be reduced, and the working efficiency is improved.

Description

Technical Field

[0001] The present invention belongs to the field of ion chromatography, and particularly relates to a temperature prediction method and device for a column oven of an ion chromatograph. Background Art

[0002] In ion chromatography analysis, as the core component of the ion chromatography system, the temperature of the chromatograph directly affects the separation effect of samples. The column oven is an important component in the chromatograph, and the temperature of its cavity is an important index for calibrating the instrument. It plays an important role in improving the column efficiency of the chromatographic column, improving the resolution of chromatographic peaks, and ensuring the repeatability of the analysis sample results. It should be noted that the temperature of the cavity is achieved by heat transfer from a heat source. The temperature of the heat source can be accurately obtained by adjusting the current, etc. However, the change in the cavity temperature is not instantaneous and takes a long time to reach a steady state (the temperature basically no longer changes).

[0003] Currently, in order to make the temperature in the column oven cavity reach the required temperature value, the commonly used method is to first set an initial heat source temperature, and then wait for several hours until the cavity temperature is stable. Then, the actual measured temperature value of the cavity is detected by using the temperature sensor in the cavity. If the cavity temperature does not reach the required temperature value, the temperature of the heat source is adjusted, and after waiting for a long time again until the temperature is stable, the actual measured temperature value of the cavity is detected by using the temperature sensor in the cavity. After comparison, the above steps are repeated until the actual measured temperature value of the cavity is equal to the required temperature value of the cavity. Since a long time of waiting is required after each adjustment before the next adjustment can be made, this not only takes time but also greatly reduces the work efficiency. Summary of the Invention

[0004] In order to solve the problems existing in the above-mentioned prior art, the present invention provides a temperature prediction method for a column oven of an ion chromatograph, including the following steps: Step S1, based on Newton's law of cooling, construct a temperature change model of the column oven cavity during the heating process: ; Wherein, is the value of the cavity temperature changing with time, is the temperature value finally reached by the cavity; C is a constant related to the initial temperature and the system itself, and K is the heat exchange coefficient; Step S2, given that the required temperature value of the cavity is , set the initial temperature of the heat source in the column oven to . After the heat source starts heating, select three time points t 1 , t 2 , t 3 , and , and record the cavity temperatures T corresponding to the temperature sensors in the column oven at these three moments respectively1 、T 2 、T 3 , and obtain the temperature model in S1 corresponding to each moment: , , ; Step S3, the t obtained in step S2 1 ,t 2 ,t 3 The cavity temperature values ​​T at three moments 1 、T 2 、T 3 The model formulas are combined and logarithmized: , ,get ; Step S4: Calculate the final value of the cavity temperature according to steps S2 and S3 Prediction model: ; Step S5, compare the final value of the cavity temperature The required temperature of the cavity , and then adjust the heat source temperature in advance , it should be noted that and Related, with Repeat steps S2 to S5 until equal .

[0005] Based on the above solution, in step S5, when the calculated Less than When The value is increased; when the calculated Greater than When Decrease the value.

[0006] Based on the above solution, in step S2 > .

[0007] The present invention also provides an ion chromatograph, comprising a column oven, a heat source and at least one temperature sensor, wherein the temperature of the column oven is adjusted using the temperature prediction method for an ion chromatograph column oven provided by the present invention as described above, wherein a temperature sensor detects the temperature of a column oven cavity.

[0008] Based on the above solution, the heat source is a semiconductor cooling sheet that can absorb and release heat.

[0009] Compared with the prior art, the present invention has the following beneficial effects: Reduce the waiting time after each adjustment, shorten the time required for the temperature control system, improve the system response speed, and can reduce energy consumption and improve work efficiency. Description of the Drawings

[0010] Figure 1 It is a flowchart of the column oven temperature prediction in the embodiment of the present invention; Figure 2 It is a schematic diagram of the Newton's law of cooling equation; Detailed Embodiments The present invention will be further described below in conjunction with specific embodiments.

[0011] As Figure 1 shown, the present invention provides a temperature prediction method for a column oven of an ion chromatograph, including the following steps: Step S1, construct a prediction model based on Newton's law of cooling to predict the temperature change during the heating process. For the heating process, Newton's law of cooling is adjusted to: , wherein, is the value of the cavity temperature changing with time, is the value of the final temperature reached by the cavity; C is a constant related to the initial temperature and the system itself, and K is the heat exchange coefficient. The curve of the above equation is roughly as Figure 2 shown. It should be noted that since the values of C and K are affected by the environment and the system (equipment) itself, and the values of C and K will change for different equipment or usage environments, it is difficult to obtain the values of C and K and they often change; therefore Figure 2 the curve shown is the approximate trend of the cavity temperature curve during the heating process rather than an accurate curve. Through the technical solution of the present invention, it is not necessary to consider the values of C and K, and naturally there is no need to debug in advance or obtain the values of C and K through technical means, which is applicable to all equipment and usage environments, has strong applicability, and the implementation method is as follows: Step S2, when the required temperature value of the cavity is known as , set the initial temperature of the heat source in the column oven to . After the heat source starts to heat, select three time points t 1 , t 2 , t 3 , and , and record the cavity temperatures T 1 , T 2 , T 3 corresponding to the temperature sensors in the column oven at these three moments respectively, and obtain the temperature models in S1 corresponding to each moment: , , ; Based on the above solution, in step S2 > 。

[0012] Step S3, perform operations on the cavity temperature values T 1 、t 2 、t 3 at three moments in the formula obtained in step S2: 1 、T 2 、T 3 : , , ; Specifically, by selecting time points and performing logarithmic operations, C and K are eliminated, which can simplify the temperature model and make it easier to calculate.

[0013] Step S4, according to the t 1 、t 2 、t 3 selected in step S2, obtain , so the final value of the cavity temperature can be calculated according to the formula in step S3 : , , ; Step S5, compare the final value of the cavity temperature with the required temperature value of the cavity , and then adjust the heat source temperature in advance. It should be noted that is related to and changes with . Repeat steps S2 to S5 until is equal to .

[0014] Specifically, in step S5, when the calculated is less than , increase the value of ; when the calculated is greater than , decrease the value of .

[0015] To monitor the temperature inside the cavity in real time, at least one temperature sensor is provided. According to the prediction algorithm provided by the present invention, there is no need to wait until the equilibrium state after each adjustment of the heating element and then determine whether the cavity temperature meets the conditions, effectively saving time.

[0016] According to an embodiment of the prior art, the required temperature value of the column oven cavity is , and the heat source temperature in the column oven is set to , greater than , wait for several hours until the temperature in the column oven stabilizes, and check the cavity temperature value displayed by the temperature sensor at this time , compare with , if they are not equal, then adjust the heat source temperature in the column oven , repeat the above steps until = .

[0017] In the existing technical solution, each time the heat source temperature is adjusted, it is necessary to wait for several hours, so multiple adjustments require a long waiting time.

[0018] Using the technical solution of the present invention for temperature prediction and adjustment, as a specific embodiment (but not limited to this), the solution is as follows: The required temperature value of the column oven cavity is , and the heat source temperature in the column oven is set to , greater than , starting from the time point when heating begins, select the time point t 1 after heating for 10 minutes, select the time point t 2 after 3 minutes, and select the time point t 3 after another 3 minutes, and record the cavity temperatures T 1 , T 2 , T 3 corresponding to the temperature sensor in the column oven at these three moments respectively. According to the prediction model , obtain the internal temperature of the cavity at equilibrium = , compare with , if they are not equal, then adjust the heat source temperature in the column oven , repeat the above steps until = .

[0019] According to the embodiment provided by the present invention, after each adjustment of the heat source temperature, it is possible to adjust again after waiting for 16 minutes, which greatly shortens the waiting time required after adjustment. What is obtained in this solution is calculated from other measured temperature values, while that of the existing technical solution needs to be obtained by actual measurement of the temperature sensor in the cavity after the cavity temperature stabilizes, and there is an essential difference between the two.

[0020] The present invention also discloses an ion chromatograph, which is characterized by comprising an oven, a heat source and at least one temperature sensor. The temperature of the oven is adjusted by using the temperature prediction method for the oven of the ion chromatograph disclosed by the present invention. One of the temperature sensors detects the temperature of the cavity, and the heat source is a semiconductor refrigeration sheet capable of absorbing and releasing heat.

[0021] According to the present invention, by selecting time points and establishing a prediction model, the uncertainties of C and K in the temperature change model based on Newton's law of cooling in different systems and environments are eliminated, the heat source is adjusted in advance, the waiting time after each adjustment of the heat source is reduced, and the working efficiency is improved.

[0022] The foregoing are only the preferred embodiments of the present application and are not intended to limit the present application. For those skilled in the art, the present application may have various changes and modifications. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included within the protection scope of the present application.

[0023] Although the specific implementation manners of the present invention have been described above, they do not limit the protection scope of the present invention. Those skilled in the art should understand that various modifications or deformations that can be made without creative efforts on the basis of the technical solution of the present invention are still within the protection scope of the present invention.

Claims

1. A temperature prediction method for an ion chromatograph column oven, characterized in that: The following steps are involved: Step S1, based on Newton's law of cooling, construct a temperature change model of the column oven cavity during the heating process: ; in, is the value of cavity temperature changing with time, is the final temperature of the cavity; C is a constant, which is related to the initial temperature and the system itself; K is the heat exchange coefficient; Step S2, it is known that the required temperature value of the cavity is , set the initial temperature of the heat source in the column oven to , after the heat source starts heating, three time points t1, t2, t3 are selected, and , and record the cavity temperatures T1, T2, and T3 corresponding to the temperature sensors in the column oven at these three moments, and obtain the temperature model in S1 corresponding to each moment: , , ; Step S3, the model formulas of the cavity temperature values ​​T1, T2, and T3 at the three moments t1, t2, and t3 obtained in step S2 are combined and logarithmically calculated: , ,get ; Step S4: Calculate the final value of the cavity temperature according to steps S2 and S3 Prediction model: ; Step S5, compare the final value of the cavity temperature The required temperature of the cavity , and then adjust the heat source temperature in advance , repeat steps S2 to S5 until equal .

2. The temperature prediction method of an ion chromatograph column oven according to claim 1, characterized in that: In step S5, when the calculated Less than When The value is increased; when the calculated Greater than When Decrease the value.

3. The temperature prediction method of an ion chromatograph column oven according to claim 1, characterized in that: In step S2 > .

4. An ion chromatograph, characterized in that: It comprises a column oven, a heat source and at least one temperature sensor, wherein the temperature of the column oven is adjusted using a temperature prediction method for an ion chromatograph column oven as described in any one of claims 1 to 3, wherein a temperature sensor detects the temperature of a column oven cavity.

5. An ion chromatograph according to claim 4, characterized in that: The heat source is a semiconductor refrigeration sheet that can absorb and release heat.

Images