Multi-temperature-measuring-point arrangement and temperature measuring method for cryogenic equipment

Abstract

The invention is suitable for accurate temperature measurement of cryogenic equipment, and particularly relates to a multi-temperature-measurement-point arrangement and temperature measurement method of cryogenic equipment. Through the weighted average temperature of the plurality of temperature measurement points, the temperature condition in the equipment can be obtained more accurately, and the temperature measurement error caused by non-uniform temperature under extreme working conditions is reduced. The method comprises the following steps: 1, preliminarily and uniformly arranging temperature measuring points according to an effective space; 2, acquiring temperature data through experiments or simulation; 3, an improved Mini Batch k-means clustering algorithm is carried out; 4, determining the optimal clustering number, and obtaining different temperature measurement point combination schemes; 5, selecting a temperature measurement point combination with the minimum error sum of squares as a temperature measurement point arrangement scheme for multi-point temperature measurement; 6, the weight coefficient of each temperature measuring point is calculated through a Critic weight method; and 7, calculating a weighted average temperature as a feedback temperature.

Description

Technical Field

[0001] The invention relates to the field of temperature detection, and in particular to an arrangement of temperature measuring thermal resistors and a temperature measuring method. Background Art

[0002] Cryogenic treatment has strict requirements on the performance of equipment. The temperature measurement accuracy of the equipment will directly affect the effect of cryogenic treatment. Due to the extreme working conditions of the cryogenic equipment when it is rapidly cooled, the temperature field in the cryogenic equipment will become very uneven, and it is difficult to accurately obtain the overall temperature change in the equipment with only one temperature measurement point. Summary of the invention

[0003] In order to obtain the real temperature distribution in the equipment, theoretically, a large number of temperature measurement points need to be arranged for temperature feedback. However, too many temperature measurement points will increase the manufacturing cost of the equipment, and too many temperature measurement points will make the data complex and difficult to process. Therefore, the reasonable arrangement of temperature measurement points is an important prerequisite for multi-point temperature measurement.

[0004] The purpose of the present invention is to propose a multi-point temperature measurement method for cryogenic equipment to solve the problem that a single temperature measurement point cannot represent the overall effective space temperature, and to propose a reasonable arrangement method for multiple temperature measurement points.

[0005] The present invention is achieved through the following technical solutions:

[0006] According to a first aspect of the present invention, a method for optimizing the arrangement of temperature measurement points of thermal resistors of cryogenic equipment is provided, comprising:

[0007] Calculate the effective space and design a reasonable thermal resistor bracket so that the thermal resistors are evenly arranged in the effective space.

[0008] For cryogenic equipment of a certain model, temperature data can be obtained through experimental measurement. For cryogenic equipment of an undetermined model, temperature data can be obtained through fluent fluid simulation.

[0009] Based on the acquired temperature data, cluster analysis is performed to obtain the appropriate number of clusters and clustering results. The selected clustering method is the improved Mini Batch k-means clustering method. The improved Mini Batch K-means can improve the efficiency of the algorithm and reduce the running time within an acceptable accuracy sacrifice range. In addition, this algorithm can help avoid the problem of local optimal solutions and ensure that a better cluster center configuration is found.

[0010] In the clustering results obtained, one temperature measurement point is selected from each category to combine and obtain different combinations of temperature measurement points. The sum of square errors between each combination and the average temperature in the equipment is calculated. The temperature measurement point combination with the smallest sum of square errors is selected by comparison as the thermal resistor arrangement plan for multi-point temperature measurement.

[0011] According to a second aspect of the present application, a temperature measurement method for weighted feedback temperature at multiple temperature measurement points is provided, comprising:

[0012] According to the selected combination of temperature measurement point locations, the critic weight is calculated by the error value of each temperature measurement point location to the average temperature in the device.

[0013] The weighted average temperature is calculated based on the calculated weight coefficients of each temperature measurement point and used as feedback on the temperature inside the cryogenic equipment. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] The drawings herein are incorporated into the specification and constitute a part of the specification, illustrate embodiments consistent with the present application, and together with the specification are used to explain the principles of the present application, and do not constitute an improper limitation on the present application.

[0015] Figure 1 It is a flow chart of the arrangement of multiple temperature measurement points and the multi-point temperature measurement method for cryogenic equipment;

[0016] Figure 2 It is the flowchart of the proposed improved Mini Batch k-means clustering algorithm;

[0017] Figure 3 is a schematic diagram showing a preliminary arrangement of a thermal resistor support and a thermal resistor according to an exemplary embodiment; In the figure: (1) effective space of deep cold box, (2) thermal resistor bracket, (3) PT100 thermal resistor. Specific implementation plan

[0018] The present invention is described in detail below in conjunction with the accompanying drawings and specific embodiments. This embodiment is implemented based on the technical solution of the present invention, and provides a detailed implementation method and specific operation process, but the protection scope of the present invention is not limited to the following embodiments.

[0019] Embodiment: Here, the SLX-R6 deep freezer is used as an example for explanation.

[0020] A multi-temperature measurement point arrangement and temperature measurement method for a cryogenic device, characterized in that it comprises the following steps:

[0021] Step 1. According to the effective space of the cryogenic equipment, make preliminary temperature measurement point arrangement, and arrange them evenly in the effective space, close to the edge of the wall. Since the effective space is cylindrical, a cylindrical bracket is used to evenly arrange the thermal resistors in three layers, with a thermal resistor set at 120° in each layer, for a total of 9 thermal resistors.

[0022] Step 2. Run the cryogenic equipment experimentally to collect temperature data of 9 thermal resistors with different cooling rates and different insulation times.

[0023] Step 3. Using the improved Mini Batch k-means clustering algorithm, the temperature data of the nine temperature measurement points are clustered and analyzed according to the temperature change law.

[0024] Step 4. In this example, clustering calculation shows that it is most appropriate when 3 clusters are selected, so 3 temperature measurement points are selected as temperature feedback measurement points for multi-point temperature measurement. Now select one temperature measurement point from each category for combination, and there are a total of 12 groups of temperature measurement point layout plans.

[0025] Step 5. Calculate the sum of squares of the average temperature of the 12 temperature measurement point layouts and the average temperature in the deep cold box, and select the layout with the smallest sum of squares of the error. At this point, the selection of the multi-temperature measurement point layout is completed.

[0026] According to the selected temperature measurement point arrangement scheme, the temperature measurement method of multiple temperature measurement points is described below:

[0027] Step 6. Use the temperature data of the selected three temperature feedback measurement points and the average temperature to calculate the difference, which is used as the data for calculating the weight coefficient. Use the Critic weight method to calculate the weight coefficients of the three temperature feedback measurement points.

[0028] Step 7. Calculate the weighted average temperature of the three temperature feedback measurement points as the feedback temperature.

[0029] Implementation effect, through the comparison of the two temperature measurement methods, it can be clearly seen that the multi-point temperature measurement method effectively reduces the peak value of uneven temperature generated during the rapid cooling process of the deep cold box, and improves the temperature measurement accuracy.

[0030] The above content is a further detailed description of the present invention in combination with a specific preferred embodiment. It cannot be determined that the specific embodiments of the present invention are limited to this. For ordinary technicians in the technical field to which the present invention belongs, without departing from the concept of the present invention, they can also make several simple deductions or substitutions, which should be regarded as belonging to the present invention and the scope of patent protection determined by the submitted claims.

Claims

1. A multi-temperature measurement point arrangement and temperature measurement method for a cryogenic device, characterized in that; For cryogenic equipment of a certain model, temperature data can be obtained through experimental measurement. For cryogenic equipment of an undetermined model, temperature data can be obtained through fluent fluid simulation. The obtained temperature data is subjected to improved Mini Batch k-means clustering analysis to obtain the optimal number of clusters and clustering results. The multi-temperature measurement point arrangement method with the smallest sum of square errors from the average temperature value is selected, the weight coefficient of each temperature measurement point is determined, and the weighted average temperature is calculated, that is, the multi-temperature measurement point arrangement and temperature measurement method of the cryogenic equipment; The method comprises the following steps: Step 1-1. For a certain model of cryogenic equipment, temperature data can be obtained through experimental measurement. According to the effective space of the cryogenic equipment, a corresponding thermal resistor fixing bracket is made to arrange the preliminary temperature measurement points evenly in the effective space and close to the edge of the wall. According to the different effective spaces of the equipment, 9 to 12 temperature measurement points are generally set. The number of temperature measurement points can be increased for large equipment; Step 1-2. For cryogenic equipment of undetermined model, temperature data can be obtained through fluent fluid simulation, three-dimensional modeling of the effective space of the equipment can be carried out, grids can be divided, and temperature measuring points can be set for simulation calculation. The temperature measuring points should be evenly arranged in the effective space and close to the edge of the wall. According to the effective space of the equipment, 9 to 12 temperature measuring points are generally set. The number of temperature measuring points can be increased for large equipment; Step 2. Through experiments / simulations, collect temperature data of each temperature measurement point with different cooling rates and different holding times; Step 3. Using the improved Mini Batch k-means clustering algorithm, the temperature data of each temperature measurement point is clustered and analyzed according to the temperature change law; Step 4. The best cluster number confirmed by calculation is the best number of thermal resistors used in the multi-point temperature measurement method. In the obtained clustering results, one temperature measurement point is selected from each class and combined with the temperature measurement points selected from other classes to obtain different temperature measurement point combination schemes; Step 5. Calculate the sum of square errors between the average temperature of each temperature measurement point and the average temperature of all temperature measurement points in the device. Compare and select the temperature measurement point combination with the smallest sum of square errors as the thermal resistor arrangement plan for multi-point temperature measurement; Step 6. The temperature data of the selected temperature feedback measurement point and the average temperature are calculated as the difference, which is used as the data for calculating the weight coefficient. The weight coefficient of the selected temperature measurement point is calculated using the Critic weight method. Step 7. Calculate the weighted average temperature of the selected temperature feedback measurement points as the feedback temperature.

2. The multi-temperature measurement point arrangement and temperature measurement method of a cryogenic equipment according to claim 1, characterized in that: The improved Mini Batch k-means clustering algorithm makes the algorithm more robust through multiple optimization methods, helps to avoid the problem of local optimal solutions, and ensures that a better cluster center configuration is found.

3. The multi-temperature measurement point arrangement and temperature measurement method of a cryogenic equipment according to claim 1, characterized in that: The preliminary temperature measurement point arrangement is generally arranged at 20 mm from the wall surface in the effective space, and this position is close to the feedback temperature measurement thermal resistor of the equipment.

4. The multi-temperature measurement point arrangement and temperature measurement method of a cryogenic equipment according to claim 1, characterized in that: The optimal number of clusters is the number of temperature measurement points for the final multi-point temperature measurement, which can be confirmed using the elbow plot method and the silhouette coefficient method.

5. The multi-temperature measurement point arrangement and temperature measurement method of a cryogenic equipment according to claim 1, characterized in that: The temperature measuring thermal resistor is a PT100 thermal resistor, which is suitable for low temperature working conditions.

6. The multi-temperature measurement point arrangement and temperature measurement method of a cryogenic equipment according to claim 1, characterized in that: The critic weight method calculates the weight coefficient based on the comparison strength of the evaluation index and the conflict between the indexes to comprehensively measure the objective weight of the index. While considering the temperature value volatility of a single temperature measurement point, the correlation of multiple temperature measurement points is also taken into account.

7. The multi-temperature measurement point arrangement and temperature measurement method of a cryogenic equipment according to claim 1, characterized in that: The feedback temperature is the weighted average temperature obtained by adding the temperature values ​​of each temperature measuring point multiplied by the weight coefficient.

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