JP2563669B2 - Decompression heating device - Google Patents

Description

TECHNICAL FIELD The present invention relates to a heating device for heating under reduced pressure.

2. Description of the Related Art As a prior art of a heating device for cooking under reduced pressure, there is JP-A-59-41717.

The publication discloses a cooker capable of decompressing a hermetically sealed cooking chamber to enable a new cooking method which has never been available.

That is, decompressing during cooking, an example of selecting a finished state from conventional planar to three-dimensional omelet or okonomiyaki, an example of reducing the water content without raising the temperature to around 100 ° C , There is a description about an example of accelerating foaming of bread and cake to make it fluffy.

According to the cooker disclosed in the publication, when pressure reduction cooking is desired, the pressure to be cooked is set by the set pressure (temperature) adjusting dial while observing the set pressure (temperature) display section.
The movement of the set pressure (temperature) cooking dial is transmitted to the pressure switch via the connecting rod to change the operating pressure.

As shown in FIG. 5 of the publication, the set pressure (temperature) display section shows the pressure and the corresponding temperature. If the set pressure (temperature) adjusting dial is turned, a single pointer is also shown. It is presumed that it moves on the scale.

Then, by setting an appropriate cooking time with a timer and pressing the start switch, a voltage is applied to the selected heat source (magnetron or heater) to start heating. At the same time, the decompression pump also starts to operate, but the decompression inside the cooking chamber starts a little later than this, and the delay relay operates.
It's time to open the solenoid valve.

Eventually, when the pressure falls below the set value, the pressure switch is turned off, the decompression pump is shut off, and the decompression pump stops with a slight delay.

When cooking is continued under such depressurized conditions, the pressure increases due to the generation of steam from food and the air leakage from the cooking chamber, and the pressure switch is turned on again to depressurize to a predetermined value.

When the time set by the timer elapses, power supply to the heat source is stopped and cooking is completed.

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention In the above publication, as an example of reduced pressure cooking, 100 ° C.
Although a substance that reduces the water content (drying) without raising the temperature to the vicinity is described, if the boiling point is reduced by heating to reduce the boiling point and heating is performed, it is useful for cooking products such as milk and sake cans having a low appropriate temperature.

However, in such a conventional configuration, power supply to the heat source is started immediately after the start switch is turned on, so when the food is small or the temperature of the food is high, steam is generated before the pressure in the cooking chamber reaches a predetermined value. Begin to. Therefore, the suitable temperature is temporarily exceeded.

Further, if the amount of steam generated in the initial stage is large, the decompression pump will not be able to reach the predetermined value. That is, the pressure in the heating chamber does not reach the predetermined value, and heating is performed at a temperature exceeding the appropriate temperature.

In addition, the operating unit can set the desired pressure (temperature) and display this set pressure, but it also displays the pressure in the cooking chamber during decompression or indicates whether the set value has been reached. It is not possible to do this, and there remains concern about whether decompression is being performed properly for this reason.

Therefore, an object of the present invention is to realize a heating device that can perform heating of a material having a low appropriate temperature by reduced pressure cooking for lowering the boiling point without failure, and that an operator can easily check the progress of the heating device.

Means for Solving the Problems In order to achieve the above object, the present invention is a heating means for heating an object to be heated, a boiling point setting means for freely inputting a boiling point of water, and a decompression means for decompressing a heating chamber. A pressure detecting means for detecting the pressure in the heating chamber or the depressurizing means, a display means for displaying the boiling point in the heating chamber, and a depressurizing means and a heating means for converting the boiling point information inputted by the boiling point setting means into a pressure. And a control unit for controlling.

In the decompression / heating apparatus of the present invention, the control unit controls the decompression unit while using the pressure detection unit, decompresses the heating chamber to a pressure at which the set boiling point is almost obtained, and detects using the display unit. The boiling point according to the pressure is displayed, while controlling the pressure reducing means so that the pressure is maintained, the power supply to the heating means is stopped for at least the initial period of heating for a predetermined period. It is possible to realize a decompression heating device that can reliably perform heating without failure and that allows an operator to easily check the progress.

Example Hereinafter, a reduced pressure heating apparatus in an example of the present invention will be described with reference to the drawings.

As shown in FIG. 2, a door body 2 is rotatably supported at the front opening of the main body 1, and a boiling point setting means 4, a heating time setting means 5 and a display means 6 are arranged on the operation panel 3. ing.

In the present embodiment, the boiling point setting means 4 is formed by a key, and by tapping or pressing continuously, a desired boiling point can be set according to the number of operations or the operation time. Also,
The heating time setting means 5 is composed of a knob and a volume or encoder linked to the knob. By rotating the knob, the heating time is set according to the rotation position or the number of revolutions of the knob.

The display means 6 is composed of a fluorescent display tube, an LED and the like, the details of which are as shown in FIG. 3. The structure and contents to be notified will be described later in detail.

As shown in FIG. 1, an object 8 to be heated is housed in the heating chamber 7, and the inside of the heating chamber is a packing 9 arranged on the periphery of the door body 2.
Is sealed through.

In the present embodiment, which is the heat source 10, the magnetron is coupled to the heating chamber 7 by the waveguide 11, and the opening is sealed with a dielectric 12 such as synthetic resin or ceramic with silicon putty or the like.

The object to be heated 8 is placed on a rotating mounting table 13 in order to eliminate uneven heating caused by standing waves of microwaves. The mounting table 13 includes a pair of magnets 14 for the purpose of sealing the inside of the heating chamber 7.
The object to be heated 8 is rotated by being driven from outside the heating chamber by 14 'and the driving means 15 in a non-contact manner.

The air in the heating chamber 7 is exhausted by a vacuum pump which is a pressure reducing means 17 from an exhaust hole 16 provided on one wall surface of the heating chamber. Reference numeral 18 is a cooling means for cooling the exhaust gas, and 19 is a water capturing means for removing the water content contained in the exhaust gas.

The pressure sensor, which is the pressure detecting means 20, is arranged on either one wall surface of the heating chamber 7 or the exhaust system, but in the present embodiment, it is provided in the exhaust system after the water behind the cooling means 18 is removed.

The control unit 21 decodes the commands inputted from the boiling point setting means 4 and the time setting means 5 which are connected, and outputs the display data to the display means 6 in order to make a corresponding notification.

Further, the control unit 21 detects the signal of the pressure sensor 20 by a detection circuit.
Monitor through 22. Then, the power supply and operation to the magnetron 10, the vacuum pump 17 and the driving means 15 are controlled by the driver 2 respectively.
Control via 3, 24, 25.

Now, the configuration of the display means and the contents to be notified will be described.

As shown in FIG. 3 (a), the display means is a 4-digit numerical value display section for displaying the heating time, a bar-shaped boiling point display section located below the display section, and a cooking status indicating whether or not power is supplied to the heat source. And a decompression status indicating the operation of the decompression means.

In the structure of such display means, as shown in FIG. 3 (b), first, a desired heating temperature is inputted by the boiling point setting means, and the temperature is displayed.

In the illustrated example, the temperature is set to 50 ° C, which is suitable for "liquor cans". In the boiling point display, the segments below 50 ° C are lit continuously and the segments above 55 ° C are unlit.

Next, when the heating time is set by the heating time setting means, the set time is displayed on the numerical value display section. In the illustrated example, "3 minutes" is set.

Of course, a configuration in which the order of setting the boiling point and the heating time is reversed is possible, and a configuration of accepting the input from either is naturally possible.

When the boiling point and the heating time are set, heating is started.
As shown in FIG. 3 (c), when the heating is started, the decompression status indicating that the vacuum pump is operating blinks. Then, the boiling point corresponding to the pressure in the heating chamber detected by the pressure sensor is displayed.

The illustrated example shows that the boiling point is reduced to 75 ° C., that is, the internal pressure of the heating chamber is reduced to about 290 mmHg.

At this time, since the magnetron has not been supplied with power yet, the cooking segment remains off and the heating time is not counted down.

The set boiling point of 50 ° C is blinking, and the current boiling point in the refrigerator is 75 ° C.
It is devised so that you can visually grasp the difference with.

With this configuration, it is possible to easily grasp the progress of heating, whether the pump is operating properly, and the like.

Next, the relationship between the pressure in the heating chamber during heating, the mode of power supply to the heat source, and the transition of the food temperature will be described.

FIG. 4 (a) shows the transition of the pressure in the heating chamber during heating, which is also the output detected by the pressure sensor.

When heating is started, the vacuum pump first evacuates the air in the heating chamber and decompresses it (“decompression cycle”).

During this time, the control unit converts the boiling point set by the boiling point setting means into the corresponding pressure Pa, and continues to supply power to the pump until the internal pressure of the heating chamber reaches this Pa value by the pressure sensor, and reaches the predetermined value Pa. After that, the power supply to the vacuum pump is controlled to maintain this value.

If such control is not performed, the internal pressure of the heating chamber continues to drop to a certain value determined by the capacity of the vacuum pump as shown by the broken line.

Now, when the internal pressure of the heating chamber reaches a predetermined value Pa, the fourth
Power supply to the magnetron begins ("heating cycle"), as shown in Figure (b).

By thus reducing the power supply to the magnetron in the depressurization cycle, the internal pressure can be reliably reduced to the predetermined value Pa even if the object to be heated is small or its temperature is high, and the set boiling point is not covered. Heated material does not exceed even temporarily. In addition, a large amount of steam is not generated during the depressurization cycle, and it is possible to prevent the vapor from reaching the predetermined value Pa.

Incidentally, it is of course possible to irradiate the microwave from a slightly earlier time without waiting until the internal pressure of the heating chamber reaches the Pa value, thereby shortening the time.

The optimum temperature of the heated object depends on the type of heated object,
Freely selectable using the boiling point setting means. An example is given in the table below.

In order to prevent it from becoming too hot by reheating, it is necessary to lower the internal pressure to the extent that the boiling point slightly decreases, and for milk or sake cans, it is necessary to lower the internal pressure to a considerably low value in order to obtain an appropriate temperature.

With vegetable vegetables, cooking cannot be completed unless the temperature is kept close to 100 ° C for a while, so there is no need to reduce the pressure. In this case, set the heating time and start heating.

The operator knows the optimum temperature for each object to be heated from such a list published in a cookbook, etc., and can freely set the corrected value by reflecting the taste of each person by using the boiling point setting means. .

Now, when entering the heating cycle, the food temperature starts to rise as shown in FIG. 4 (c).

In the heating cycle, since the internal pressure of the heating chamber is controlled to the Pa value, the food temperature basically does not exceed the boiling point T _a determined by the Pa value.

Since the optimum temperature is not exceeded, if the heating time is set to be slightly longer, the condition close to the optimum temperature is maintained for a while, and it is possible to improve the heating unevenness inherent to microwave heating. That is, the temperature of the portion with the lowest temperature rises steadily, but the temperature of the portion with the highest temperature does not exceed the optimum temperature.

If the pressure is not reduced, the food temperature will change as shown by the broken line in Fig. (C), and if the heating time is set a little longer in order to eliminate the uneven heating, the temperature will exceed the optimum temperature immediately. .

As described above, according to the present invention, the reduced pressure cooking for lowering the boiling point can be reliably performed, the operator can easily check the progress of the reduced pressure cooking, and the uneven heating can be eliminated.

Next, an example of the operation of the control unit will be described. As shown in the flowchart of FIG. 5, when heating is started, the set boiling point T _a is first converted into the corresponding internal pressure P _a (a), and the pump is started (b). Microwaves are not yet applied (c).

Then, the internal pressure P is detected by the pressure sensor (d),
The P value is converted into the corresponding boiling point T value, and the display data corresponding to the display means is output (e).

Then, it is judged whether or not the detected internal pressure P value has reached a predetermined value Pa, that is, P ≧ Pa (f). Internal pressure is a predetermined value
This operation is repeated as long as it is higher than Pa. It is a "decompression cycle".

When the internal pressure becomes lower than Pa, the pump is stopped (g) and power supply to the microwave generating means is started (h). This is the start of the "heating cycle".

Then, the heating time set in the timer is counted down and gradually reduced (i). Next, it is checked whether or not the heating time has elapsed (j), and while the heating time remains, detection of the pressure P (d) and conversion display to temperature (e), and determination of P ≦ Pa (f ) Is repeated.

While the P value is equal to or less than the Pa value, the pump is kept stopped (g), the microwave is irradiated (h), and the countdown (i) of the timer proceeds.

Then, when the P value exceeds the Pa value again, the pump is started (b) and the microwave is stopped (c). Subsequently, pressure detection (d), temperature conversion display (e), and determination of P ≦ Pa (f) are repeated. That is, the microwave irradiation and the countdown of the timer are stopped, and the processing is repeated until the pump again reduces the internal pressure of the heating chamber to the Pa value or less.

Eventually, when the timer times out, the pump is stopped (k), microwave irradiation is also completed (1), and heating is completed.

With the above configuration, the set heating time is reduced only while the microwave is being radiated, that is, while the internal pressure of the heating chamber is below the Pa value, and the sum of the microwave on-times becomes the heating time. Match.

In the example of FIG. 3B, the set heating time is the sum of microwave irradiation times t ₁ , t ₂ , t ₃ , t ₄ , and t ₅ .

EFFECTS OF THE INVENTION As described above, in the decompression / heating apparatus of the present invention, the pressure detection means and the display means are provided, the pressure in the heating chamber is reduced to a pressure at which the set boiling point is almost obtained, and the detection is performed using the display means. The boiling point according to the pressure is displayed and the pressure reducing means is controlled so that the pressure is maintained, while the power supply to the heating means is suspended for at least the initial period of heating for a predetermined period, so that the milk has an appropriate temperature such as a can of sake. Low heating can be done without failure by lowering the boiling point.

Further, if the heating time is set slightly longer, it is possible to eliminate uneven heating.

In addition, it is possible to realize a safe decompression / heating device in which the operator can easily check the progress of the process and quickly recognize abnormalities in the pump.

[Brief description of drawings]

FIG. 1 is a block diagram showing the structure of a reduced-pressure high-frequency heating apparatus in one embodiment of the present invention, FIG. 2 is a front perspective view of the same, and FIG.
FIG. 3A is a diagram showing the configuration of the display means, FIG. 3B is a diagram showing a display example when setting the same boiling point and heating time, and FIG.
FIG. 4 (c) is a diagram showing a display example during the heating, FIG. 4 (a) is a diagram showing changes in pressure in the heating chamber during the heating, and FIG. 4 (b) is power supply to the heating means. FIG. 4 (c) is a diagram showing an increase in the food temperature, and FIG. 5 is a flowchart showing the operation of the control unit. 4 ... Boiling point setting means, 4 ... Display means, 7 ... Heating chamber, 10 ... Heating means, 17 ... Decompression means, 20 ... Pressure detection means, 21 ... Control section

 ─────────────────────────────────────────────────── ─── Continuation of the front page (56) Reference JP-A-59-41717 (JP, A) JP-A-3-279712 (JP, A) Actual development Sho-58-109194 (JP, U)

Claims (1)

(57) [Claims] 1. A heating chamber for accommodating and sealing an object to be heated, a heating means connected to the heating chamber, a control unit for controlling power supply to the heating unit, and a boiling point of water for the control unit. A boiling point setting means that can input an input to the heating chamber, a decompression means that decompresses the heating chamber to a pressure at which the boiling point commanded by the boiling point setting means is obtained, and the control unit that detects the pressure in the heating chamber or the decompression means. And a display unit for displaying the boiling point in the heating chamber, wherein the control unit converts the boiling point information input by the boiling point setting unit into a pressure, while using the pressure detecting unit. Control the pressure reducing means to reduce the pressure in the heating chamber to a pressure at which the set boiling point is approximately obtained, and display the boiling point according to the detected pressure using the display means so that the pressure is maintained. Before While controlling the pressure reducing means, heating under reduced pressure device configured to pause for a predetermined period of time power supply to at least the heating of the initial to the heating means.