Microwave Treatment Device Frequency Sweep for Heating Uniformity
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Solution Overview
Problem
Conventional microwave treatment devices struggle to achieve even heating, particularly when heating targets like frozen food, as the permittivity changes with temperature, causing microwaves to converge unevenly.
Innovation Solution
The microwave treatment device includes a heating chamber, a microwave generator, an amplifier, a feeder, a detector, a controller, and storage. It performs a frequency sweep and adjusts the output level and oscillation time based on detected microwave power and reflected wave ratios to control heating evenness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the frequency and output level of microwaves are controlled to make heating even, then the heating uniformity is improved, but the microwaves still converge to defrosted portions due to permittivity changes, resulting in uneven heating
Solution Approach 1:
The patent applies dynamics by making the microwave frequency adjustable and variable during the heating process. The frequency is not fixed but can be dynamically changed in response to detected heating conditions, allowing the system to adapt to permittivity changes in the heating target and prevent microwave convergence to defrosted portions.
Solution Approach 2:
The patent implements feedback by using a detector to monitor the heating state and reflected microwave power, then using this information to adjust the microwave frequency and output level. This closed-loop control system continuously adapts to changes in the heating target's permittivity, preventing uneven heating caused by defrosting.
2Device complexity
If the microwave frequency is fixed, then the device complexity is reduced, but the heating pattern becomes fixed and cannot adapt to temperature-induced permittivity changes
Solution Approach 1:
The system transitions from a fixed frequency to a dynamically adjustable frequency. The microwave generator can change frequency in response to detected heating conditions, allowing the heating pattern to adapt without requiring complex multi-frequency hardware. The dynamics principle is applied through software-controlled frequency modulation.
Solution Approach 2:
The patent changes the microwave frequency parameter during operation based on detected heating conditions. By modulating the frequency parameter, the system adapts the heating pattern to match the changing permittivity of the heating target, achieving versatility through parameter variation rather than hardware complexity.
3Productivity
If the output level is increased to heat frozen food faster, then the productivity is improved, but the micrawaves converge more strongly to defrosted portions, worsening heating uniformity
Solution Approach 1:
The patent changes multiple parameters including frequency and output level based on the heating state. For frozen food, the system can operate at higher output levels for faster heating while simultaneously adjusting frequency to prevent convergence to defrosted portions. This coordinated parameter adjustment maintains both productivity and heating uniformity.
Solution Approach 2:
The system uses periodic frequency sweeps and pulsed heating patterns to distribute energy more evenly. By periodically varying the frequency or applying pulsed power, the system prevents continuous convergence to defrosted portions while maintaining overall heating speed, resolving the contradiction between productivity and uniformity.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This configuration improves heating evenness by reducing local temperature increases and permittivity changes, ensuring more uniform microwave distribution and absorption across the heating target.
Implementation Method 1
a microwave generator (3) that generates a microwave having an arbitrary frequency in a predetermined frequency band
Implementation Method 2
a detector (6) that detects incident microwave power and reflected microwave power that returns from the heating chamber to the feeder
Data Source
Figure 1
Figure 2A~2B
Figure 3(a)~3(b)
AI summary
A microwave treatment device according to one aspect of the present disclosure includes a heating chamber, a microwave generator, an amplifier, a feeder, a detector, a controller, and a storage. The microwave generator generates a microwave having an arbitrary frequency in a predetermined frequency band. The amplifier amplifies the microwave and outputs the amplified microwave as incident microwave power. The feeder supplies the incident microwave power to the heating chamber. The detector detects the incident microwave power and reflected microwave power that returns from the heating chamber to the feeder. The storage stores the incident microwave power and the reflected microwave power in association with the frequency of the microwave and time elapsed since the start of heating. The controller causes the microwave generator to execute a frequency sweep over the predetermined frequency band. The controller controls the microwave generator and the amplifier on the basis of the incident microwave power and the reflected microwave power detected during the frequency sweep. According to the present aspect, the heating evenness can be improved.