Calculation method for heating uniformity of microwave heating

Abstract

The invention belongs to the technical field of microwave heating, and particularly discloses a method for calculating the heating uniformity of microwave heating. The method disclosed by the invention comprises the following steps: firstly, a plurality of containers are distributed and placed in a central symmetry manner by taking the centermost position of a microwave heating cavity as a center; then, all the containers are filled with water loads with the same temperature, and after standing, the initial temperature of the water load in each container is recorded; then, the microwave heating equipment is started and runs for a fixed time at the maximum power; then, at the instant after microwave heating is finished, the ending temperature of the water load in each container is recorded; and finally, calculating the heating uniformity of the microwave heating equipment based on the initial temperature and the end temperature of each container. According to the method, the heating uniformity of the microwave equipment can be calculated, the influence of the initial temperature on a result is eliminated, and the method also has a standard process characteristic capable of being repeatedly realized. The method can be widely applied to heating uniformity evaluation of microwave equipment.

Description

Technical Field

[0001] This invention belongs to the field of microwave heating technology, and specifically relates to a method for calculating the heating uniformity of microwave heating. Background Technology

[0002] Microwaves refer to electromagnetic waves with frequencies ranging from 300MHz to 300GHz. Their heating properties on dielectric materials make them a new technology in the field of processing heating. Compared with traditional heating methods, microwave heating has advantages such as rapid heating, fewer byproducts, and environmental friendliness. As the microwave heating market expands year by year, the demand for high-precision and uniform heating in industrial and household microwave ovens is increasing, aiming to promote and apply microwave heating technology in more high-precision fields. In recent years, many manufacturers have begun to focus on optimizing the uniformity of microwave heating.

[0003] However, current industry standards for microwave oven performance indicators focus primarily on efficiency and energy consumption. A sufficiently universal evaluation method for heating uniformity is lacking, thus failing to provide crucial reference for breakthroughs in uniform heating technology. Current methods for calculating temperature uniformity mainly involve selecting several representative measurement points, calculating the standard deviation, mean, and coefficient of variation (the result of standard deviation divided by the mean) based on the measured temperatures at each point to quantify and compare temperature uniformity. However, this method cannot eliminate the influence of initial temperature on the calculation results, and the selection of several representative points is not conducive to standardizing the testing process.

[0004] In addition, the current method usually involves manual temperature measurement after heating is completed, which has two significant drawbacks: First, during the time interval between the end of heating and the completion of all measurement point readings, the temperature of each water load will drop due to heat exchange with the environment, and the cooling rate may be different at different locations, introducing additional errors; Second, the use of metal temperature probes (such as thermocouples) will generate arcing and interference in the microwave field, making it impossible to perform real-time measurement during the heating process.

[0005] To address this issue, a quantitative calculation method is needed that features a repeatable and standardized testing procedure, eliminates the influence of initial temperature, and accurately captures the instantaneous temperature at the end of heating. This will contribute to the development of high-performance microwave uniform heating technology. Summary of the Invention

[0006] The purpose of this invention is to provide a method for calculating the heating uniformity of microwave heating. This method eliminates the influence of initial temperature on the results and has the characteristics of a standardized process that can be repeated. It can be applied to different microwave heating cavities and provides a reliable basis for the optimization of microwave heating technology. The inventor's second objective is to provide an application of the calculation results obtained by the above calculation method in microwave parameter optimization, microwave sterilization, and intelligent cooking.

[0007] To achieve the above objectives, the technical solution adopted by this invention is as follows: A method for calculating the heating uniformity of microwave heating includes the following steps performed sequentially: S1, n 2 The containers are arranged in a centrally symmetrical manner with respect to the center of the microwave heating cavity, where n is an odd number and n>3; S2. Fill all containers with water loads at the same temperature, and record the initial temperature of the water loads in each container after they have settled. S3. Start the microwave heating equipment and run it at maximum power for a fixed time; S4. Immediately after the microwave heating ends, record the final temperature of the water load in each container; S5. Calculate the heating uniformity of the microwave heating equipment based on the initial and final temperatures of each container.

[0008] As a limitation, the formula for calculating the heating uniformity in step S5 is: In the formula, To measure the quantitative value of heating uniformity of microwave heating equipment, This represents the difference between the final temperature and the initial temperature in a single container.

[0009] As a second limitation, the container is made of a non-metallic material that is not reactive to microwaves.

[0010] As a third limitation, the device used to record the initial temperature and the end temperature in steps S2 and S4 is a multi-channel data acquisition instrument.

[0011] As a further limitation, each of the containers is provided with a temperature sensor, the probe of which is in contact with the water load; The signal output terminals of all temperature sensors are connected to the signal input terminals of the multi-channel data acquisition instrument.

[0012] As a further clarification, the temperature sensor is a fluoride fiber optic temperature sensor.

[0013] An application of the calculation results obtained according to the above calculation method in microwave parameter optimization, microwave sterilization, and intelligent cooking.

[0014] The present invention, by adopting the above-described technical solution, achieves the following technical advancements compared to existing technologies: (1) The method of the present invention uses an odd number of containers (n>3) with a central symmetric distribution to ensure the spatial representativeness of the test samples, and the standardized container layout makes the test process repeatable; the temperature of all water loads is recorded simultaneously at the moment of heating, which effectively avoids the temperature decay error caused by heat exchange, and avoids the time delay problem of manual temperature measurement; the calculation is based on the difference between the initial temperature and the end temperature, which eliminates the interference of the initial temperature on the uniformity evaluation, and makes the result more objectively reflect the actual heating effect of the microwave field; the method provides a standardized, accurate and easy-to-operate quantitative tool for the research and development of high-performance microwave uniform heating technology, which can significantly promote the application of microwave heating technology in industrial and high-precision fields; (2) The method of the present invention eliminates the time delay error of manual temperature measurement by synchronously acquiring the initial and final temperatures of all containers through multiple channels, ensuring the instantaneity and accuracy of data acquisition; the fluoride fiber optic sensor probe directly contacts the water load, and its non-metallic properties avoid arcing interference in the microwave field, supporting real-time temperature measurement; all sensor signals are centrally connected to the data acquisition instrument, constructing a standardized and reusable automated testing system, which significantly improves the evaluation efficiency and reliability, and provides a high-precision and anti-interference quantitative tool for the research and development of microwave uniform heating technology.

[0015] This invention belongs to the field of microwave heating technology. It can calculate the heating uniformity of microwave equipment. While eliminating the influence of initial temperature on the results, it also has the characteristics of a standardized process that can be repeated. It can be applied to different microwave heating cavities and provides a reliable basis for the optimization of microwave heating technology. Attached Figure Description

[0016] The accompanying drawings are provided to further illustrate the invention and form part of the specification. They are used together with the embodiments of the invention to explain the invention and do not constitute a limitation thereof.

[0017] In the attached diagram: Figure 1 This is a flowchart of the processing in Embodiment 1 of the present invention; Figure 2 This is a schematic diagram of the structure of a single container in Embodiment 1 of the present invention; Figure 3 This is a schematic diagram of the arrangement of containers in Embodiment 1 of the present invention. Detailed Implementation

[0018] The preferred embodiments of the present invention will now be described with reference to the accompanying drawings. It should be understood that the preferred embodiments described herein are for illustrative and explanatory purposes only and are not intended to limit the scope of the invention.

[0019] Example 1 like Figure 1As shown, this embodiment is a method for calculating the heating uniformity of microwave heating, which includes the following steps performed sequentially: S1, n 2 The containers are arranged in a centrally symmetrical manner with the center of the microwave heating cavity as the center, where n is an odd number and n>3.

[0020] In this embodiment, n is 5, and the number of containers is 25. The actual number of containers can be adjusted according to the size of the microwave equipment. Figure 2 and Figure 3 As shown, the length, width and height of the containers are 42mm, 42mm and 30mm respectively, the volume is 50ml, and the spacing between the containers is 3mm when they are placed.

[0021] In this embodiment, the container is made of glass, but this can be changed according to the actual situation, as long as the container is made of a non-metallic material that does not react with microwaves.

[0022] S2. Fill all containers with water loads at the same temperature, and record the initial temperature of the water load in each container after letting it stand.

[0023] In this embodiment, each container is equipped with a fluoride fiber optic temperature sensor. The probe of the temperature sensor is fixed to the bottom or lower side wall of each container and is in contact with the water load in the container.

[0024] A multi-channel data acquisition unit is used to record the measured temperatures of the temperature sensors, and the signal output terminals of all temperature sensors are connected to the signal input terminals of the multi-channel data acquisition unit.

[0025] S3. Start the microwave heating equipment and run it at maximum power for a fixed time.

[0026] During the heating process, the fluoride fiber optic temperature sensor works continuously and records the temperature changes of the water load in each container.

[0027] S4. Immediately after the microwave heating ends, record the final temperature of the water load in each container.

[0028] After the microwave heating equipment is turned off, the multi-channel data acquisition instrument automatically records the end temperature of the water load in each container within 1 second.

[0029] S5. Calculate the heating uniformity of the microwave heating equipment based on the initial and final temperatures of each container.

[0030] Specifically, the formula for calculating heating uniformity is: In the formula, To measure the quantitative value of heating uniformity of microwave heating equipment, This represents the difference between the final temperature and the initial temperature in a single container.

[0031] In summary, this embodiment can calculate the heating uniformity of microwave equipment. While eliminating the influence of initial temperature on the results, it also has the characteristics of a standardized process that can be repeated and is applicable to different microwave heating cavities, providing a reliable basis for the optimization of microwave heating technology.

[0032] Example 2 This embodiment illustrates the application of calculation results obtained based on the calculation method described in Embodiment 1 in microwave parameter optimization, microwave sterilization, and intelligent cooking.

[0033] In terms of microwave parameter optimization, the power / frequency of industrial microwave equipment or household microwave ovens can be tuned. By quantifying the temperature differences at various points, "hot spots" and "cold spots" in the microwave field can be accurately identified. Combined with numerical simulation, the cavity structure can be optimized or the feed position can be adjusted to make the energy distribution more uniform.

[0034] In the field of microwave sterilization, it can be used to develop microwave sterilization processes for food or medical devices. The calculated uniformity data can be used to establish a "temperature-sterilization efficiency" model, ensuring that all areas reach the minimum lethal temperature. For example, in the sterilization of liquid pharmaceuticals, by analyzing and optimizing the temperature difference between containers, localized overheating or underheating can be prevented, avoiding problems such as damage to active ingredients or incomplete sterilization.

[0035] The calculation results can also be used to develop AI cooking algorithms for high-end microwave ovens. By combining the calculated data with a database of food thermal properties, the power curve can be dynamically adjusted to achieve three-dimensional and uniform heating, thereby improving cooking quality.

Claims

1. A method for calculating the heating uniformity of microwave heating, characterized in that, This includes the following steps performed sequentially: S1, n 2 The containers are arranged in a centrally symmetrical manner with respect to the center of the microwave heating cavity, where n is an odd number and n>3; S2. Fill all containers with water loads at the same temperature, and record the initial temperature of the water loads in each container after they have settled. S3. Start the microwave heating equipment and run it at maximum power for a fixed time; S4. Immediately after the microwave heating ends, record the final temperature of the water load in each container; S5. Calculate the heating uniformity of the microwave heating equipment based on the initial and final temperatures of each container.

2. The method for calculating the heating uniformity of microwave heating according to claim 1, characterized in that, The formula for calculating the heating uniformity in step S5 is: In the formula, To measure the quantitative value of heating uniformity of microwave heating equipment, This represents the difference between the final temperature and the initial temperature in a single container.

3. The method for calculating the heating uniformity of microwave heating according to claim 1 or 2, characterized in that, The container is made of a non-metallic material that is not reactive to microwaves.

4. The method for calculating the heating uniformity of microwave heating according to claim 1, characterized in that, The device used to record the initial and final temperatures in steps S2 and S4 is a multi-channel data acquisition instrument.

5. The method for calculating the heating uniformity of microwave heating according to claim 4, characterized in that, Each of the containers is equipped with a temperature sensor, the probe of which is in contact with the water load; The signal output terminals of all temperature sensors are connected to the signal input terminals of the multi-channel data acquisition instrument.

6. The method for calculating the heating uniformity of microwave heating according to claim 5, characterized in that, The temperature sensor is a fluoride fiber optic temperature sensor.

7. The application of the calculation results obtained by the calculation method according to any one of claims 1 to 6 in microwave parameter optimization, microwave sterilization, and intelligent cooking.

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