KR940011870A - Microwave Weight Detection Device and Detection Method - Google Patents

Abstract

The present invention detects the weight of food in a microwave oven. In the past, the weight was detected using a piezoelectric element, but the voltage generated by the piezoelectric element is non-linearly changed according to the weight of the food, so it is very difficult to accurately detect the weight of the food. It is not only difficult but also requires a look-up table that stores the weight of each voltage in advance, and the voltage generated by the piezoelectric element varies according to the installation state of the sensor and the change of ambient temperature and humidity. The sensor was easily damaged by applying a continuous impact by the weight of food to the device.

The present invention provides a support roller by installing a weight sensor having two electrodes facing each other and an annular spacing holder positioned between the two electrodes to maintain a constant interval on the rotation track of the support roller of the rotary ring. The interval between the two electrodes changes as the weight sensor is pressed so that the capacitance changes linearly with the weight of the food, and the oscillation frequency changes linearly with the change of the capacitance of the weight sensor. In addition to detecting the weight of food by frequency, almost no errors occur regardless of changes in ambient temperature and humidity, and even when used for a long time, the weight can be accurately detected.

Description

Microwave Weight Detection Device and Detection Method

As this is a public information case, the full text was not included.

1 is a view showing a weight detection apparatus of the present invention,

(A) (B) of Figure 2 is an exploded perspective view and a cross-sectional view showing a weight sensor used in the weight detection apparatus of the present invention,

3 (a) (b) is a cross-sectional view and a plan view showing a state in which the weight sensor is installed by the weight detection apparatus of the present invention,

4 is a graph showing a change in capacitance of the weight sensor according to the present invention.

Claims (5)

A rotary ring 3 installed in the heating chamber 1 to rotate the rotary table 2, and a support roller installed at the periphery of the rotary ring 3 so as to stably rotate the rotary table 2 (4). ), A weight sensor (5) installed on the rotational track of the support roller (4) to generate displacement as the support roller (4) is pressed, a drive means (11) for driving the drive unit of the microwave oven, and The sensor signal processing means 12 for converting the displacement of the weight sensor 5 into an electrical signal, and the weight of the food to be heated by the arc of the sensor signal processing means 12 by performing an operation command of the operation unit 13. And a control unit (14) for heating and cooking food by controlling the driving means (11) while determining the weight of the microwave oven. The weight detection device according to claim 1, wherein the weight sensor (5) is a variable capacitor whose capacitance varies according to the weight applied by the support roller (4). 2. The apparatus of claim 1, wherein the sensor signal processing means (12) is an oscillator whose frequency varies according to the displacement of the weight sensor (5). In the first process of measuring the frequency (FRO) of the no-load state, the second process of measuring the frequency (FRI) of the weight of the food weight by the set number of times to store the lowest frequency (FRI), and in the second process The third step of subtracting the measured minimum value from the no-load frequency (FRO) to calculate the frequency difference and summing the frequency difference, and repeating from the second process until the frequency difference summed in the third process becomes the set number of times And a fifth step of calculating a weight at a frequency obtained by adding up the set number of times in the third step. The weight detection method according to claim 4, wherein the second step is processed as an error when the difference between the measured frequency FRI and the frequency FRO at no load is equal to or greater than a preset time. ※ Note: The disclosure is based on the initial application.