JPS5835333A - Cooking oven - Google Patents

Abstract

PURPOSE:To obtain a correct control under a high temperature by a method wherein the relative humidity and temperature of air containing steam generated from food are measured, and an absolute humidity is obtained on the base of the measurement result, thereby controlling the operation of a heating means. CONSTITUTION:The humidity sensor 9 for detecting the relative humidity of air which contains the steam generated by heating the food 4 and the temperature sensor 10 for detecting the temperature of the air are located at an exhaust port 5. The outputs of the sensors 9 and 10 are inputted into a microcomputer 16 respectively through an amplifying circuit 12, 14 and an A/D converter 13, 15. The microcomputer 16 decides a saturated moisture amount in an unambiguous manner based on the temperature information of the temperature sensor 10, and then multiplies thus obtained value with the relative humidity information from the humidity sensor 9 to decide the absolute humidity. Further, the microcomputer 16 calculates change in the absolute humidity which rises due to the steam generated by the heating of the food and controls a driving circuit 8 of the heating means 2 on the base of the calculated value.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a cooking opener for microwave ovens, etc., and more particularly to a cooking opener that automatically detects the appropriate cooking time of food and automatically controls heating means. .

Conventionally, for example, in microwave ovens, methods have been put into practical use that detect the relative humidity of food and automatically control cooking time, but this method requires methods such as wrapping the food in plastic film to emit steam all at once. However, it also had the disadvantage that it could not be used at high temperatures.

Here, the conventional cooking opening will be explained using Figs. 1 and 2. In Fig. 1, 1 is an open, 2 is a heating means, 3 is a blowing fan, and 4 is an object to be heated. 5 is an exhaust port, 6 is a humidity sensor that detects the relative humidity, 7 is a control circuit for this humidity sensor 6, and 8 is a heating means driving circuit, which heats the food 4 and converts water vapor coming from the food 4 into a humidity sensor. It is detected by a sensor 6 and the heating means 2 is controlled. That is, as shown in FIG. 2, when the food 4 is wrapped in a plastic film and heated, the internal temperature increases and the relative humidity decreases over time.

When the food 4 reaches a temperature close to the appropriate temperature, the relative humidity reaches the lowest value Hm. Eventually, water vapor erupts from the plastic film and the relative humidity begins to rise rapidly. At this time, the heating means 2 is controlled by detecting the displacement Δh'fr of the relative humidity changing from the lowest relative humidity Hm to Hm.

Since the relative humidity is controlled in this way, if the food 4 is not wrapped in plastic film and is cooked under high temperature and high humidity conditions, steam will gradually come out as the temperature rises. Even if the temperature rises, the relative humidity does not decrease much, so even if the food 4 reaches the appropriate temperature and the steam suddenly increases, the relative humidity increase from the lowest relative hot water temperature Hm will not reach △h, and the temperature will rise to the appropriate temperature. control is not possible. On the other hand, if you cook under low temperature and low humidity conditions, the internal temperature will not rise much, and the relative humidity will increase significantly due to a small amount of steam from food 4, resulting in false detection due to steam leaking from food 4, resulting in incorrect detection. I can't control it. In addition, in the case of food 4 with a small capacity, the amount of steam generated is small, so even if steam is generated, if the relative humidity decreasing effect due to temperature is greater, the relative humidity increase change from the minimum relative humidity Hm will be △h is not achieved, and proper control cannot be achieved. Furthermore, even if the food 4 is wrapped in a plastic film, the saturated water vapor pressure will increase rapidly under high temperature conditions, so even if the amount of water vapor coming out of the food 4 is a little large,
The relative humidity increase change is small, and the relative humidity increase displacement from the lowest relative humidity Hm does not reach Δh, making it impossible to perform proper control.

These drawbacks stem from the inherent characteristics of relative humidity, in which the relative humidity generally changes significantly with a small amount of steam at low temperatures, and does not change much even with a large amount of steam at high temperatures.

The object of the present invention is to fundamentally solve these problems and to enable automatic proper cooking even under high-temperature conditions without wrapping food in plastic film.

First, to explain the present invention in detail, in the method according to the present invention, instead of detecting the relative humidity that changes secondarily depending on the amount of steam generated from food as in the past, This method detects the amount itself.

Here, absolute humidity is generally expressed as follows.

Therefore, absolute humidity also decreases as the temperature increases, but the saturated water vapor pressure in a normal cooking atmosphere is not very large, so even if the temperature increases, the decrease in absolute humidity is sufficient compared to the amount of steam generated from food. Because it is small, it is possible to reliably detect steam generated from food.

Also, as shown in Figure 3, when food is primarily heated, the amount of steam generated from the food generally exceeds the decrease in absolute humidity.
The absolute humidity follows an increasing trend, and when the food reaches a proper cooking state, the amount of steam generated from the food reaches Hd. That is, the absolute humidity displacement △h from the lowest absolute humidity Ha
f: Detect and control the heating means.

FIG. 4 shows an example of the overall configuration of a cooking oven according to the present invention. In the figure, 1, 2, 3, 4, 6, 8 are the same locations as in FIG. 1, and 9 is located at the exhaust port 6. 1o is a humidity sensor that detects relative humidity, which is placed at the exhaust port 6 like this humidity sensor 9, and 1o is a temperature sensor that is placed at the exhaust port 6 like this humidity sensor 9.

A sensor 11 is a control circuit that detects absolute humidity based on signals from the humidity sensor 9 and the temperature sensor 1°. Here, the absolute humidity is generally also expressed as the following equation.

Hd: Absolute humidity (y-/rn') D: Saturated moisture content ()7m1'') HN: Relative humidity (%) In other words, in this formula, since the saturated moisture content is uniquely determined by temperature, temperature and relative humidity The absolute humidity can be determined by detecting the temperature sensor 1o in the control circuit 11.
The absolute humidity is detected by the signal from the humidity sensor 9,
It controls the drive circuit 8 that drives the heating means 2.

FIG. 6 and FIG. 6 each show an embodiment of the electric circuit portion of the cooking open according to the present invention.

First, in the embodiment shown in FIG. 6, the absolute humidity is calculated using a programmed calculation formula based on the signal from the humidity sensor 9 and the signal from the temperature sensor 10, and the heating means 2 is controlled. That is, the signal from the humidity sensor 9 is input to the humidity sensor signal amplification circuit 12, A/D converted by the A/D conversion circuit 13, and input to the microcomputer 16 as a control section, while the signal from the temperature sensor 1o is is inputted to the A/D conversion circuit 16 through the entire temperature sensor signal detection circuit 14, A/D converted, and inputted to the microcomputer 16. The microcomputer 16 uniquely determines the saturated moisture content based on the temperature information, determines the absolute humidity by multiplying this value by the relative humidity based on the relative humidity information, and determines the absolute humidity using the steam generated from the food by heating. The amount of displacement Δh'f by which is increased is calculated, and the drive circuit 8 that drives the heating means 2 is controlled. Note that 17 is a keyboard, and this keyboard 17 is an input means for instructing to start cooking, completely stopping cooking, etc. 18 is a display device, and this display device 18 is a display means for displaying input information from the keyboard 17 or cooking status.

In addition, in the embodiment shown in FIG. 6, the absolute humidity is detected by multiplying the relative humidity signal from the humidity sensor 9 and the saturated moisture content signal from the temperature sensor 1o by an external circuit, and is input to the microcomputer. and controls the heating means. That is, the signal from the humidity sensor 9 is converted into a relative humidity signal by the relative humidity detection circuit 19, and this relative humidity signal is input to the multiplication circuit 21, while the signal from the temperature sensor 1o is converted to a relative humidity signal by the saturated moisture content determination circuit 2o. The saturated water content signal is converted into a saturated water content signal, and this saturated water content signal is input as the other input to the multiplication circuit 21. This multiplication circuit 21 multiplies the saturated moisture content by the relative humidity and outputs an absolute humidity signal. This absolute humidity signal is converted into an A/D converter circuit 22.
The signal is converted into D and input to the microcomputer 16. In this microcomputer 16, the amount of displacement △ where the absolute humidity increases due to the steam generated from the food due to heating
h is detected and a drive circuit 8 that drives the heating means 2 is controlled.

゛ As seen above, in the cooking oven according to the present invention, absolute humidity is determined by the signals from the humidity sensor that detects the relative humidity of the air containing water vapor emitted from the food, the humidity sensor for the water vapor emitted from the food, and the temperature sensor. This device controls the heating means by determining the humidity, and detects the amount of steam generated from the food itself, so there is no need to wrap the food in plastic or film as in the past, and the temperature rises. However, the decrease in absolute humidity is sufficiently small compared to the amount of steam generated from food, so the steam generated from food can be reliably detected and accurate control can be performed even under high temperature conditions. It is possible. However, this provides an excellent effect in that it can be applied not only to microwave ovens but also to open ovens where the inside of the oven becomes hot.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing the overall configuration of a conventional cooking oven, FIG. 2 is a diagram showing changes in relative humidity when food is heated in the same oven, and FIG. 3 is a diagram showing the change in relative humidity when food is heated in the same oven. , a diagram showing changes in absolute humidity when food is heated, FIG. 4 is a configuration diagram of the present invention, and FIGS. 6 and 6 are block circuit diagrams showing specific examples of the electric circuit portion of the oven . 2... Heating means, 4... Food, 8...
...Drive circuit, 9...Humidity sensor, 1o.
...Temperature sensor, 1'1. =...control circuit, 1
6...Microcomputer, 19...
・Relative humidity detection circuit, 2o...Saturated moisture content determination circuit, 21...Multiplying circuit. Name of agent: Patent attorney Toshio Nakao, 1 person FI
f! 4- Figure 3 Time opening- Figure 4 Figure 5

Claims (3)

[Claims] (1) A heating means for heating food, a humidity sensor that detects the relative humidity of air containing water vapor emitted from the food, a temperature sensor that detects the temperature of the air containing water vapor emitted from the food, and the humidity and a control unit that calculates the amount of water vapor displacement generated from the food by calculating the absolute humidity from the relative humidity information from the sensor and the temperature information from the temperature sensor, and controls the heating means. Open for cooking. (2) The cooking opener as set forth in claim 1, wherein the control section is constituted by a microcomputer. (3) A relative humidity detection circuit to which the signal from the humidity sensor is input, a saturated moisture content determination circuit to which the signal from the temperature sensor is input, and a signal from the relative humidity detection circuit and the saturated moisture content determination circuit to which the signal from the relative humidity detection circuit and the saturated moisture content determination circuit are input. The control unit is composed of a multiplication circuit that calculates the absolute humidity by multiplying the signal, and a microcomputer that detects the amount of water vapor generated from the food based on the signal from the multiplication circuit and controls the heating means. A cooking opener according to claim 1.