JPS642858B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION In recent years, some home cooking appliances have a timer function or a sensor function and are aimed at automation, which tends to make them very convenient to use. A recent example is an attempt to automate cooking by detecting humidity using a humidity sensor.

However, in this case, there is the inconvenience of covering the food (food) with saran wrap or the like. This inconvenience can be eliminated by detecting temperature using the infrared sensor shown in this embodiment. However, in this case as well, only the surface temperature of the food can be detected, and the heating control method for cooking, which involves how to bring the temperature inside the food closer to the temperature on the surface, becomes a problem.

Furthermore, in the past, the only way to defrost the food was to do it manually, relying on human intuition, or using a timer or the like based on experience.

If we think about the meaning of thawing here, it means melting the ice crystals in food to reduce or reduce the freezing rate.

Furthermore, when a cooking appliance is equipped with the function of defrosting, the purpose is to defrost food in the above sense, regardless of quantity or quality. Also, it may be possible to defrost the food by using a microwave oven for a long time at low power.
The goal is to shorten this time as much as possible. There are also devices that insert a temperature probe into the food to detect the temperature and then thaw the food, but in terms of the time and effort required and the emotional aspects of humans, it is most ideal to do this without contact.

Therefore, in this example, an infrared temperature sensor that can detect the surface temperature of food without contact is mounted on a microwave oven. Become the center.

The configuration will be explained below.

FIG. 1 is a configuration diagram when an infrared temperature sensor is mounted on a microwave oven.

1 is an oven, 2 is food, 3 is a hole for guiding infrared rays from the food to an infrared temperature sensor, 4 is a chopper for chopping infrared rays, 5 is a reflector for reflecting infrared rays, 6 is a hole for guiding infrared rays from food to an infrared temperature sensor A concave mirror 7 is an infrared temperature sensor to focus the light on the temperature sensor. Reference numeral 8 has a function to know the state (open/close) of the chopper, and in this embodiment, an interrupter is used. The cooking is controlled by a control section (not shown) consisting of a microcomputer, and the control section is provided with a timer and a calculation means to measure and calculate the cooking time.

In general, when trying to automate food preparation and thawing, the biggest issues are the quantity, quality, etc.
The condition of the food (including internal temperature, etc.). In general, there is considerable variation in detecting the quantity, quality, and temperature status of food after heating it from its initial temperature to a certain appropriate temperature.
It also varies considerably depending on the shape of the food.

Therefore, as shown in this example, the food is heated from its initial temperature to a certain appropriate temperature T ₁ (25°C in this example) using almost the maximum output (full power) of the microwave oven, and the heating is stopped at T ₁ . , T ₂ (15 in this example)
Wait for the temperature to drop to ℃).

The time it takes for the temperature to drop from T ₁ to T ₂ contains a considerable amount of information about the food, and for large frozen foods, the temperature rises only at the surface until T ₁ , so the temperature drops to T ₂ . However, for small quantities of frozen products, it takes longer than the former method.

Initially, the heating output until T ₁ is set at almost the maximum output in this example, but if the heating power during this period is low, it will take time to reach T ₁ , and from T ₁ to T ₂
There is a drawback that the temperature change is not as noticeable as mentioned above.

Therefore, by detecting the time from T ₁ to T ₂ , the quantity, quality, and condition of the food can be roughly recognized, and the control sequence for cooking (thawing) after the temperature reaches T ₂ can be determined to be optimal. .

FIG. 2 illustrates this situation.

Also, since the power of the microwave oven is stopped from _T1 to _T2 , there is an advantage that noise due to radio wave induction does not enter the control circuit.

As an example, an appropriate constant K for the heating pause time
Cooking (thawing) is completed by heating from the point where the temperature drops to T ₂ for the time multiplied by .

Generally, FIG. 2 shows a correlation diagram between this heating rest time and the subsequent time until the food can be heated, cooked, and thawed. The test materials of the plot are of varying quality or weight.

If you refer to this, you can understand that although there is some variation, there is an almost inversely proportional correlation.

Therefore, the equation of the curve in Figure 2 is t23=K2/(t ₁
+K ₁ ), (t ₂₃ : time from when the surface temperature reaches T ₂ to the end of cooking, t ₁ : first heating pause time) K ₁ ,
Determine _K2 . This calculation is based on several points of t ₁ ,
This can be done by substituting t ₂₃ (data obtained from experimental values) and solving simultaneous equations. The second heating time _t23 can now be determined. In the cooking device of the present invention, all of the above calculations are performed by a microcomputer in the control section. FIG. 4 shows a functional block diagram explaining this function. The surface temperature of the food to be cooked is detected by the temperature detection section 7 and inputted to the control section 9. In the control section 9, the heating power and heating time of the microwave output drive section 12 are determined by the clock means 10 and the calculation means 11. FIG. 5 is a cloture chart for explaining the functions of the present invention. Here, the first heating power means that the surface temperature of the food to be cooked is
The second heating power is the power applied until the temperature reaches T ₁ , and the second heating power is the power applied for a period of time t 23 from T ₂ to t ₂₃ when the surface temperature of the food to be cooked reaches T 1 . In other words, the surface temperature of the food is T ₁
The food is heated with the first heating power (steps 101, 102) until the temperature reaches T2, then the heating is stopped (step 103), and the stopping is continued until the surface temperature of the food reaches _T2 (step 104). During this time, the counter of the time measuring means 10 has started (step 103), and the time from temperature T ₁ to T ₂ has elapsed.
_t12 is counted (step 105). Next, a constant K ₁ is added to the time t ₁₂ measured by the calculation means 11, and a time t ₂₃ is calculated by multiplying the reciprocal of the constant K ₂ (step 106), and the time t ₂₃ is calculated using the second heating power. (steps 107, 108) and finish cooking (step 109). Furthermore, in cases where the food is thawed after being heated for the second heating time, the thawing state of the food is further improved by providing a heating pause time for the second heating time. So, cooking,
If thawing is completed, an optimal food cooking and thawing control sequence can be obtained. In Figure 3, the above-mentioned outline is illustrated. The first heating power (up to T ₁ ) is almost at maximum output, and the second heating power (from T _{2 to}
t ₂₃ ) is more optimal for cooking and defrosting food in terms of heat conduction and other aspects.

As explained above, according to the present invention, the following effects can be expected.

Since the heating time and heating rest time are almost the same, the food can be thawed relatively well.

The optimal heating time can be determined simply by performing certain calculations.

Since the heating rest time t ₁ is used as a parameter of the heating time, it is difficult for the radio wave induction noise peculiar to microwave ovens to be added to t ₁₂ .

Since the heating power can be switched, better results can be obtained from heat conduction within the food and other factors.

[Brief explanation of drawings]

Fig. 1 is a cross-sectional view of a heating cooker showing an embodiment of the present invention, Fig. 2 is a diagram illustrating the relationship between the heating pause time and the time until the end of cooking, and Fig. 3 is a control sequence of the cooker. FIG. 4 is a functional block diagram of the cooking device, and FIG. 5 is a clochart showing the same function. 1...Oven, 2...Heated object (food), 3
... Hole inside the oven (infrared passing window), 4...
Chiyotsupa, 5...Reflector, 6...Concave mirror, 7...
...Infrared temperature sensor, 8...Interrupter.

Claims (1)

[Claims] 1. A temperature detection section that detects the surface temperature of the food by detecting infrared rays emitted from the food, and a control section consisting of a microcomputer that controls microwave output and has a clock means and a calculation means, and the control section The surface temperature of the food to be cooked is heated by the microwave output until the temperature detecting section determines the surface temperature of the food to be _T1 , and the control section controls the surface temperature of the food to be heated to _T1 . The temperature detection section detects the temperature T ₂ (T ₁ > T ₂ )
The microwave output is stopped until it is determined that
The time measuring means is configured to detect when the surface temperature of the food to be cooked is from T1 _to
The time t ₁₂ until T ₂ is reached, the calculation means adds a constant K ₁ to the time t ₁₂ , and the reciprocal thereof is:
The control unit calculates the time _t23 obtained by multiplying the constant _K2 , and
The cooking device is configured to cook the food that has reached the temperature T ₂ for the time t ₂₃ using a microwave power that is smaller than the microwave power that is applied until the food reaches the temperature T ₁ .