JP2012132624A - Heating cooker - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a heating cooker capable of preventing overheating even with a small amount of a load.SOLUTION: The heating cooker includes a microwave generating means 1, a heating chamber 2, an infrared sensor 3 for measuring a temperature of a load in a non-contact manner, a moving part 4 which moves the infrared sensor 3 to change a position for measuring a temperature in the heating chamber 2, a control means 5 which controls the microwave generating means 1 based on the temperature measured by the infrared sensor 3 and the temperature measuring position information, and a load amount determination means 6 which determines an amount of load in the heating chamber 2. In the case that the load amount determination means 6 determines that the amount of load is small, the control means 5 detects a maximum temperature among the measured temperatures, and the moving part 4 is made to move within a range which is narrower than that in the case that the load amount determination means 6 determines that the amount of the load is large and which includes a position by maximum temperature measurement. Consequently, overheating can be prevented even if a small amount of the load is heated.

Description

  The present invention relates to a cooking device used in general homes, restaurants, offices, and the like.

  Conventionally, in this type of heating cooker, by measuring the temperature by moving the infrared sensor to measure the temperature at a plurality of positions in the heating chamber, A method of heating to an appropriate temperature regardless of the position is disclosed (for example, see Patent Document 1).

JP 2002-168457 A

  However, in the conventional configuration, since the detection position is changed by moving the temperature sensor, the temperature at the same detection position can be measured only discretely. In such a case, when a small amount of load is heated, there is a problem that the load is heated to a target temperature or higher while measuring another position.

  This invention solves the said conventional subject, and it aims at providing the heating cooker which can stop a heating, without becoming overheating, even when it is a case where a small load is heated. To do.

  In order to solve the above-described conventional problems, a heating cooker according to the present invention includes a microwave generation unit, a heating chamber that stores a load heated by microwaves, and an infrared sensor that measures the temperature of the load in a non-contact manner. A movable part that moves the infrared sensor to change the temperature measurement position in the heating chamber, a control means that controls the microwave generation means based on the temperature and measurement position information measured by the infrared sensor, and a load in the heating chamber Load amount determining means for determining the amount.

  In this configuration, when the load amount determination means determines that the load amount is small, the control means detects the maximum temperature of the measured temperature, and the movable part determines that the load amount determination means has a large load amount. The range including the position where the maximum temperature is detected which is narrower than the case is movable.

  The heating cooker of the present invention can stop heating without overheating even when a small load is heated, and can improve the heating finish.

Sectional drawing of the heating cooker in Embodiment 1 of this invention The figure which shows the movable range of the infrared sensor of the heating cooker in Embodiment 1 of this invention, the figure which shows the amount of load, and the figure which shows the movable range according to the load amount of the infrared sensor The figure which shows the difference of the temperature change by the load amount of the heating cooker in Embodiment 1 of this invention. The figure which shows the output of the microwave of the heating cooker in Embodiment 1 of this invention The figure which shows the load in the heating chamber of the heating cooker in Embodiment 1 of this invention, and the figure which shows the temperature distribution in the heating chamber of the heating cooker in Embodiment 1 of this invention

  According to a first aspect of the present invention, there is provided a microwave generating means, a heating chamber for storing a load heated by the microwave, an infrared sensor for measuring the temperature of the load in a non-contact manner, and moving the infrared sensor to move the infrared sensor in the heating chamber. A movable part for changing the temperature measurement position, a control means for controlling the microwave generation means based on the temperature measured by the infrared sensor and information on the measurement position, and a load amount determination for determining the load amount in the heating chamber And when the load amount determination means determines that the load amount is small, the control means detects the maximum temperature of the measured temperature, and the load amount determination means By using a cooking device that can move the range including the position where the maximum temperature is narrower than when it is determined that the amount is large, overheating can be prevented by shortening the temperature detection interval.

  In the second invention, in particular, since the movable part of the first invention is fixed at the position where the infrared sensor measures the maximum temperature, the temperature detection interval is minimized to prevent overheating of a small load. can do.

  According to a third aspect of the invention, in particular, in the first aspect of the invention, there is provided a humidity sensor for measuring the amount of steam in the heating chamber. Since the load amount is detected from the output of the humidity sensor, the load amount can be detected quickly.

  In the fourth aspect of the invention, in particular, the load amount determination means of the first aspect of the invention can detect the load amount accurately by detecting the load amount from the temperature change rate of the infrared sensor.

  In the fifth aspect of the invention, in particular, the load amount determining means of the first aspect of the present invention can detect the load amount directly by detecting the load weight.

  In the sixth invention, in particular, the control means of the first invention changes the output of the microwave generation means before and after the load amount determination means determines the load amount, thereby preventing overheating more reliably. be able to.

  In the seventh invention, particularly when the load amount judging means of the first invention judges that the load amount is small, the control means prevents the overheating by reducing the output of the microwave generating means. can do.

  In the eighth invention, in particular, after the movable part of the first invention changes the movable range of the infrared sensor, the control means heats up to the target temperature faster by increasing the output of the microwave generating means. be able to.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. Note that the present invention is not limited to the embodiments.

(Embodiment 1)
In FIG. 1, sectional drawing of the heating cooker in the 1st Embodiment of this invention is shown. The heating cooker according to the present embodiment includes a microwave generating means 1 that generates microwaves, a heating chamber 2 that stores a load that is heated by microwaves, and an infrared sensor 3 that measures the temperature of the load in a non-contact manner. The movable unit 4 that moves the infrared sensor 3 to change the temperature measurement position in the heating chamber 2, and the control unit 5 that controls the microwave generation unit 1 based on the temperature measured by the infrared sensor 3 and information on the measurement position. And load amount determination means 6 for determining the amount of load in the heating chamber 2.

  The microwave generating means 1 usually uses a magnetron in many cases, but may be a semiconductor type. The microwave generation unit 1 generates microwaves by supplying power from an inverter circuit (not shown) or the like based on an instruction from the control unit 5. The microwave to be generated is normally 2450 MHz, but is not limited thereto.

  Microwaves are introduced into the heating chamber 2 via an antenna, and a structure in which a turntable is provided so that the antenna is fixed and the load is rotated, and the load is placed at the same position so that the antenna is rotated. There are cases where it is configured.

  The heating chamber 2 is made of metal such as aluminum or SUS, and the load is heated by placing the load in the heating chamber 2 and introducing the microwave generated by the microwave generating means 1 into the heating chamber 2. The

  Although microwaves exist in the heating chamber 2, it is ideal that only the load is heated by the microwaves. Therefore, when the heating chamber 2 is made of glass or the like, for example, the glass generates heat due to the microwave, resulting in a heating loss.

  Therefore, in order to reduce the heating loss, it is desirable to use a metal that does not generate heat by the microwave and reflects the microwave. However, since it is necessary to introduce the microwave generated from the microwave generating means 1 into the heating chamber 2, only that portion is usually changed to another material.

  The infrared sensor 3 detects the temperature in a non-contact manner, and includes a thermal type thermopile and a bolometer, a quantum type photodiode, and a phototransistor, but any type may be used.

  In particular, some thermopiles have a plurality of elements in one package, and each element can detect a temperature at a different position. Usually, in such an element, the temperature of each element is often taken out and used in many cases, but is not limited thereto.

  The movable part 4 is provided with the infrared sensor 3 and allows the infrared sensor 3 to measure different positions in the heating chamber 2 by moving the movable part 4. The movable portion 4 is suitable for determining the measurement position when a stepping motor is used, but may be a linear motor or the like.

  A rotary encoder may be used for positioning. The movable part 4 may move the infrared sensor 3 in a one-dimensional manner or in a two-dimensional manner.

  The control means 5 is connected to the microwave generation means 1, the infrared sensor 3, the movable part 4, and the like. When the user sets a heating pattern, time, or the like by an operation unit (not shown), the control unit 5 operates an inverter circuit (not shown) to supply power to the microwave generation unit 1. Generate microwaves.

  The control means 5 moves the movable part 4, measures the temperature of the load placed in the heating chamber 2 by the infrared sensor 3, changes the operating state of the microwave generation means 1 according to the result, and uses the load. Control is performed such as stopping the operation of the microwave generating means 1 after heating to a temperature desired by the person. The control means 5 is often a microcomputer, DSP, custom IC, or the like, but is not limited thereto.

  The load amount determination means 6 determines the amount of load in the heating chamber 2, the result is transmitted to the control means 5, and the control means 5 changes the control method according to the load amount. The load amount determination means 6 and the control means 5 may be the same.

  About the cooking-by-heating machine comprised as mentioned above, the operation | movement and an effect | action are demonstrated below.

  The user opens a door (not shown) and places a load in the heating chamber 2. In FIG. 1, the microwave generated by the microwave generating means 1 is introduced into the heating chamber 2 from a rotating antenna. Since the antenna rotates, the distribution of the microwave in the heating chamber 2 changes every moment, and the microwave is heated no matter where the load is placed in the heating chamber 2.

  Therefore, in the cooking device having such a configuration, the user may place the load anywhere in the heating chamber 2, but when the antenna is fixed and the load is rotated, a turn for rotating the load is performed. Since the table exists, the user needs to place the load on the turntable, but either configuration may be used.

  The user determines a heating method by an operation unit (not shown). Usually, in the case of such a heating cooker, several heating methods, such as microwave heating, light heater heating, and oven heating, can be selected.

  In this embodiment, the case of heating with microwaves will be described. In addition, there are a manual mode in which the user sets the output and time for heating, and an automatic mode in which the heating is automatically stopped only by selecting cooking contents. When the user selects them and the door is closed, heating can be started.

  When heating is started, the control means 5 moves the infrared sensor 3 by the movable part 4, the infrared sensor 3 measures the temperature in the heating chamber 2, and the control means 5 receives the temperature information and changes the control content. To do.

  For example, when the course for automatically warming a drink is selected, heating is continued until the set temperature is reached, and when the set temperature is reached, the operation of the microwave generating means 1 is stopped and the heating is performed. finish. FIG. 2A is a diagram showing a movable range of the infrared sensor of the heating cooker according to the first embodiment of the present invention, and FIG. 2B is an amount of load of the heating cooker according to the first embodiment of the present invention. (C) is a figure which shows the movable range according to the load amount of the infrared sensor of the cooking-by-heating machine in the 1st Embodiment of this invention.

  Since it is not known where the load is placed in the heating chamber 2, the movable part 4 has a 1 to d 1 so that the infrared sensor 3 can measure all the places in the heating chamber 2 as shown in FIG. Move the range.

  However, since the detection position is changed by moving the infrared sensor 3 in this way, the temperature at the same detection position can be measured only discretely. For example, when the infrared sensor 3 measures the temperature at the location a1 in FIG. 2A, the infrared sensor 3 sequentially changes the measurement position by the movable portion 4, and the positions b1, c1, and d1 are also measured. Thereafter, the movable unit 4 moves the infrared sensor 3 in the reverse direction, and the temperature is measured in order of d1, c1, and b1, and then the temperature is also measured at the position of a1.

That is, for the ends in the cabinet such as a1 and d1, the temperature can be measured only at a time interval of approximately 2t, where t is the time taken to move the infrared sensor 3 from a1 to d1. On the other hand, at the center in the cabinet, the measurement can be made at a time interval of about t.

  In any case, temperature information at the same position can be acquired only at intervals of time t or more. For this reason, there has been a problem that the temperature of the load is heated to the target temperature or higher during the time t to 2t during which other positions are measured. In particular, in the case of a small amount of load, since the temperature rises quickly, the overshoot becomes large.

  An object of the present invention is to provide a cooking device that can stop heating without overheating even when a small load is heated.

  In the present invention, the amount of load is detected by the load amount determination means 6, and overheating is prevented by shortening the interval measured by the infrared sensor 3. Specifically, when the load is as shown in FIG. 2B, the infrared sensor 3 only needs to move within the range of b1 to c1 as shown in FIG.

  In other words, the temperature detection in the range of a1 to b1 and c1 to d1 and the movable time can be omitted. Therefore, it is possible to reduce the overshoot because the measurement interval can be shortened and whether the load has reached the target temperature can be detected quickly. Therefore, heating can be stopped at a temperature close to the target temperature, which brings benefits to the user.

  Here, a load amount detection method will be described. FIG. 3 is a diagram showing a difference in temperature change depending on the load amount of the cooking device according to the first embodiment of the present invention. There are roughly three methods for detecting the load amount.

  The first method is a determination method based on the rate of change of temperature. As shown in FIG. 3, when the same load is heated with the same load and with the same power microwave, the time required for heating from the temperature FT1 to the temperature FT2 is Ta for a small amount, whereas In the case of a large amount, Tb is satisfied, and Ta <Tb.

  The relationship between Ta and Tb is almost proportional to the amount. Therefore, when the temperature of the load after a predetermined time elapses is equal to or lower than the predetermined temperature, the load amount determination means 6 detects that the load is a small amount.

  Here, when the infrared sensor 3 is moved, the predetermined time cannot be set to be less than the time required for the movement, but needs to be a time that does not cause overheating even with a small load (for example, 15 seconds). ).

  Further, the predetermined temperature required for the determination is a temperature before overheating and is preferably equal to or lower than the heating target temperature. However, since the optimum temperature differs depending on the load, it is set to 50 ° C., for example.

  Further, since the slope of FIG. 3 increases when the microwave output is large, the microwave output is decreased until the load amount determination means 6 determines the load amount, and after the determination is completed. Overheating can also be prevented by increasing the output of the microwave.

  Further, the output of the microwave after the determination may be changed according to the load amount. FIG. 4 shows the microwave output of the cooking device according to the first embodiment of the present invention. Assume that the load amount determination means 6 determines the load amount at a time Tc (for example, 15 seconds) from the start of heating.

  At that time, the output of the microwave until time Tc is O2. The microwave output O2 is set so as not to overheat at the time Ta even with a small load. At time Tc, the load amount determination means 6 determines the load amount from the temperature information of the infrared sensor 3.

  That is, if the temperature is equal to or higher than the predetermined temperature, it is determined that the load is small, and if the temperature is equal to or lower than the predetermined temperature, it is determined that the load is large. The criteria for determination may be changed more finely.

  When the load amount is determined in this way, the determination result is transmitted from the load amount determination means 6 to the control means 5, and the control means 5 may change the output of the microwave in accordance with the load amount. Specifically, when the load amount is large, the microwave output is increased from O2 to O3, so that even a large amount of load can be saved in a short time. On the other hand, in the case of a small amount of load, there is a possibility of overheating. Therefore, by reducing the microwave output from O 2 to O 1, overheating can be made difficult.

  These microwave output changes make it difficult to overheat even when the load is small, and need not be changed in this way.

  Next, a second load amount detection method will be described. The humidity sensor 7 detects water vapor generated from the load. When the humidity sensor 7 is installed in the heating chamber 2, problems such as heat resistance and noise generation occur, and thus the humidity sensor 7 is installed in the exhaust port 8. The humidity sensor 7 includes a relative humidity sensor and an absolute humidity sensor, but either one may be used.

  The exhaust port 8 is for discharging water vapor generated in the heating chamber 2 to the outside of the heating chamber 2, and has a configuration in which water vapor or the like does not easily leak into the heating chamber 2 from other than the exhaust port 8. By doing so, the humidity sensor 7 can detect water vapor generated from the load.

  When the load is heated, moisture contained in the load is released as steam by heating. The amount of steam released depends on the amount of load. Therefore, the load amount determination means 6 can determine that the load is small when the amount of steam detected by the humidity sensor 7 is small, and can determine that the load is large when the amount of steam is large. The timing for determination may be, for example, after a lapse of a certain time from heating or after the temperature detected by the infrared sensor 3 reaches a predetermined temperature, but is not limited thereto.

  Next, a third load amount detection method will be described. The load amount determination means 6 installs a weight sensor 9 at the lower part of the placement portion on which the load is placed, and detects the weight of the placement portion and the load. Since the weight data measured in this way includes the weight of the placing unit and the container for loading food as a load, it cannot be said to be an accurate load weight.

  However, since the mounting portion has a constant weight, it can be subtracted, and by registering the weight of the vessel, it is possible to accurately calculate the weight of only the food that is originally intended to be heated. Further, although the accuracy is inferior, the weight of only the food may be calculated on the assumption that a percentage of the weight measured by the weight sensor 9 is the weight of the vessel.

  In that case, the trouble of registering the weight of the vessel can be saved. From the weight of the food obtained in this way, the load amount determination means 6 can calculate the amount of load. In this case, since the load amount can be determined before heating, it is possible to heat with a large amount of power from the beginning of heating when the load amount is large, and with a small amount of power from the beginning of heating when the load amount is small. It is.

When the load determined as described above is small, even if the temperature is measured by the infrared sensor 3 as described above, the update of the temperature information is delayed by moving the infrared sensor 3, and as a result In some cases, overheating occurred.

  In the present invention, overheating can be prevented by shortening the time required to move the infrared sensor 3 and speeding up the update of the temperature information.

  Since the infrared sensor 3 does not know where the load is placed in the heating chamber 2 as described with reference to FIG. 2, the infrared sensor 3 is movable to be able to measure the temperature in the entire range in the storage. However, the range that actually needs to be measured is limited. FIG. 5A is a diagram showing a load of the heating cooker according to the first embodiment of the present invention, and FIG. 5B is a temperature distribution in the heating chamber 2 of the heating cooker according to the first embodiment of the present invention. Is shown. Among the ranges of the interiors a2 to g2, a2 to b2 and f2 to g2 are ranges where nothing is placed, and the temperature FT1 at that time is the ambient temperature.

  On the other hand, b2 to f2 are temperatures higher than the ambient temperature FT1, but the actual food is c2 to e2, and b2 to c2 and e2 to f2 are containers for placing food. . Therefore, as the movable range of the infrared sensor 3, c2 to e2 are sufficient.

  However, it is difficult to determine from the temperature information that c2 to e2 are actually food temperatures, and b2 to c2 and e2 to f2 are temperatures of food containers.

  Therefore, in the present invention, the maximum temperature measured by the infrared sensor 3 is detected (DT3 in FIG. 5B), and the movable portion 4 is at the position where the maximum temperature C is detected (d2 in FIG. 5B). If the range including is moved, the range including the temperature of the food can be moved reliably.

  The movable range does not necessarily need to be c2 to e2, and is desirably a range narrower than c2 to e2 including d2. Moreover, it does not necessarily need to move and may be fixed at the position of d2. In this way, the position where the maximum temperature is reached is a position where the radio wave tends to concentrate or the temperature of the load is likely to rise, so it is sufficient to prevent overheating if the temperature at this position is measured. It can be performed and heating with good finish can be performed.

  As described above, by adopting the configuration as in the present invention, when the load amount determination means 6 determines that the load amount is small, a range narrower than when the load amount is determined to be large is moved. Thus, it is possible to provide a heating cooker that can shorten the time required for detection and can prevent overheating while moving other ranges.

  As described above, the cooking device according to the present invention can quickly detect the temperature even when the load is small, and can prevent overheating. It is effective for heating cookers.

DESCRIPTION OF SYMBOLS 1 Microwave generation means 2 Heating chamber 3 Infrared sensor 4 Movable part 5 Control means 6 Load amount determination means 7 Humidity sensor 8 Exhaust port 9 Weight sensor

Claims (8)

A microwave generating means, a heating chamber for storing a load heated by microwaves, an infrared sensor for measuring the temperature of the load in a non-contact manner, and moving the infrared sensor to change the temperature measurement position in the heating chamber A movable part, a control means for controlling the microwave generation means based on the temperature and measurement position information measured by the infrared sensor, and a load amount determination means for determining the amount of load in the heating chamber, When the load amount determination means determines that the load amount is small, the control means detects the maximum temperature of the measured temperature, and the movable part determines that the load amount determination means that the load amount is large. A cooking device that can move the range including the position where the highest temperature measured is narrower than the case. The cooking device according to claim 1, wherein the movable part is fixed at a position where the infrared sensor measures the maximum temperature. The humidity sensor for measuring the amount of steam in the heating chamber is provided, and the load amount determination means detects the load amount from the output of the humidity sensor after a predetermined time has elapsed by the control means driving the microwave generation means. The cooking device described. The heating cooker according to claim 1, wherein the load amount determination means detects the load amount from a temperature change rate of the infrared sensor. The heating cooker according to claim 1, wherein the load amount determination means determines the load amount by detecting the weight of the load. The cooking device according to claim 1, wherein the control means changes the output of the microwave generation means before and after the load amount determination means determines the load amount. The cooking device according to claim 1, wherein when the load amount determination means determines that the load amount is small, the control means reduces the output of the microwave generation means. The cooking device according to claim 1, wherein the control means increases the output of the microwave generation means after the movable portion changes the movable range of the infrared sensor.