JP2009008309A - Heating cooker - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To more precisely control a temperature in a wide temperature range from a comparatively low temperature to a high temperature when heating cooking is performed by detecting an inside temperature. <P>SOLUTION: First and second thermistors 26, 27 different from each other in detection temperature characteristics are disposed as inside temperature detecting elements detecting the temperature in a cooking chamber 1. A steam supply device 10 and hot-air heaters 2, 3 are controlled on the basis of detection temperature of the second thermistor 27 superior in detection accuracy of high temperature, when the steam cooking of high temperature with a set temperature of 100°C or higher is performed while supplying steam into the chamber by the steam supply device 10. The steam supply device 10 and the hot-air heater 3 are controlled on the basis of the detection temperature of the first thermistor 26 superior in detection accuracy of low temperature, when the steam cooking of low temperature of lower than 100°C (for example, 40°C) is performed. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a cooking device configured to control an in-compartment heating unit and a steam supply unit based on a temperature detected by an in-compartment temperature detecting element that detects a temperature in the cooking cabinet.

In the heating cooker, in addition to cooking by heating means such as an electric heater or a magnetron, a heating cooker that can be cooked by steam has been proposed (for example, see Patent Document 1). In this case, the temperature in the cooking chamber (heating chamber) is detected by a chamber temperature detection element composed of a thermistor, and the electric heater for heating the chamber and the steam supply means are controlled so that the chamber has a set temperature. It is said.
JP 2005-308315 A

By the way, in this kind of heating cooker, when cooking with the internal temperature set to a high temperature of 200 ° C. or higher, or cooking with the internal temperature set to a relatively low temperature of about 40 to 50 ° C., for example. May do.
In the thing of above-mentioned patent document 1, there is only one in-case temperature detection element which detects the temperature in a cooking chamber. If it is attempted to detect and control from a relatively low temperature of 40 to 50 ° C. to a relatively high temperature of 200 ° C. or more with a single internal temperature detection element, the detection error becomes large and accurate temperature control is performed. There is a problem that can not be.

  The present invention has been made in view of the above-described circumstances, and its purpose is to detect temperature in a wide range from a relatively low temperature to a high temperature in a case where cooking is performed by detecting the internal temperature, and the temperature is more precisely set. It is providing the cooking device which can be controlled.

In order to achieve the above-described object, the present invention provides a cooking chamber that accommodates an object to be cooked, a heating unit that heats the inside of the cooking chamber, a steam supply unit that supplies steam to the cooking chamber,
In a heating cooker comprising an internal temperature detection element for detecting the temperature in the cooking chamber, and a control means for controlling the internal heating means and the steam supply means based on the detected temperature of the internal temperature detection element, The inside temperature detection element is provided with a plurality of elements having different detection temperature characteristics.

  In the present invention, as an internal temperature detecting element for detecting the internal temperature, an internal temperature detecting element suitable for detecting a relatively low temperature and an appropriate element for detecting a relatively high temperature are used. By using it, it becomes possible to control the temperature more precisely in a wide temperature range from a relatively low temperature to a high temperature.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
First, a schematic configuration of the cooking device will be described based on FIG. FIG. 1 is a front view showing a configuration of a main part of a heating cooker. Specifically, a known exterior member such as an outer frame that forms an outer shell, a front-side opening / closing door, and an operation panel that sets a cooking menu and the like. It is the front view of the state which removed the, Comprising: The rectangular container-shaped cooking chamber 1 which mainly opened the front surface is shown.

  In FIG. 1, the outer side hot air heater 2 and the inner side hot air heater 3 which each consist of an electric heater (seeds heater) are provided in the back side of the rear wall 1a of the cooking chamber 1 as an internal heating means. These outer and inner hot air heaters 2 and 3 are each formed in a rectangular frame shape, and the inner hot air heater 3 is arranged concentrically inside the outer hot air heater 2. A fan 4 a of the circulation fan device 4 is disposed inside the inner hot air heater 3. In the rear wall 1a, a suction port 5 is formed in a central portion corresponding to the fan 4a, and blowout ports 6 are formed in upper and lower portions so as to correspond to the outer and inner hot air heaters 2 and 3, respectively. The suction inlet 5 and the blower outlet 6 are each comprised from many holes.

Here, when the circulation fan device 4 is driven and the fan 4a is rotated, the air in the cooking chamber 1 is sucked into the fan 4a side from the suction port 5 in the central portion, and the air around the fan 4a is It blows out in the cooking chamber 1 from the lower blower outlet 6, and what is called circulation ventilation is performed. At this time, when the outer hot air heater 2 and the inner hot air heater 3 are energized to generate heat, the hot air heated by the hot air heaters 2 and 3 is blown out from the blower outlet 6 into the cooking chamber 1.
An upper heater 7 made of a planar electric heater is provided on the upper surface of the ceiling wall 1b of the cooking cabinet 1, and a lower heater 8 made of a planar electric heater is also provided on the lower surface of the bottom wall 1c. These upper heater 7 and lower heater 8 also constitute in-chamber heating means for heating the inside of the cooking chamber 1.

  A steam supply device 10 as a steam supply means is disposed on the left side of the cooking chamber 1 in the figure. The steam supply device 10 includes an evaporation unit 11 and a water supply unit 12. The evaporation unit 11 includes a hollow evaporation container 13 made of aluminum die-casting, and two steam upper heaters 14 and a steam lower heater 15 each made of a rod-shaped electric heater (seeds heater) cast into the evaporation container 13. And a plurality of steam discharge ports 16 communicating with the inside of the evaporation container 13, and the steam discharge ports 16 face the cooking chamber 1 from the left side wall 1 d of the cooking chamber 1. The evaporation unit 11 is provided with a steam thermistor 17 (shown only in FIG. 2) as a temperature detection element for detecting the temperature in the evaporation container 13.

  The water supply unit 12 includes a water storage tank 18, a water supply pump 19, and water supply pipes 20a and 20b. Of the two pipes 20a and 20b, one pipe 20a is connected between the outlet of the water storage tank 18 and the suction port of the water supply pump 19, and the other pipe 20b is the discharge port of the water supply pump 19 and the evaporation container. 13 inlets are connected. The water storage tank 18 is positioned below the bottom wall 1c of the cooking cabinet 1, and is mounted so that it can be taken in and out from the front.

  Here, when the water supply pump 19 is driven, the water in the water storage tank 18 is sucked into the water supply pump 19 through the pipe 20a, and the water in the water supply pump 19 passes through the pipe 20b into the evaporation container 13 of the evaporation unit 11. To be supplied. At this time, when the steam upper heater 14 and the steam lower heater 15 of the evaporation container 13 are energized and generate heat, the water supplied into the evaporation container 13 is heated by the steam upper heater 14 and the steam lower heater 15. Then, the steam is converted to steam, and the steam is supplied into the cooking chamber 1 from the steam discharge port 16.

  Usually, in this type of heating cooker, as a heating means other than those described above, although not shown, a magnetron as a heating means by high frequency is provided outside the cooking chamber 1, and the high frequency generated by the magnetron is supplied to the waveguide. For example, it can be supplied from the bottom wall 1 c of the cooking cabinet 1 into the cooking cabinet 1. In the cooking chamber 1, a mounting table 21 on which an object to be cooked is placed is detachably disposed. The mounting table 21 is detachably supported by a receiving portion 22 provided at a position where the left and right side walls 1d and 1e of the cooking cabinet 1 are opposed to each other.

  The cooking chamber 1 is provided with ventilation means. That is, the intake port 23 is formed near the front of the left side wall 1d, and the exhaust port 24 is formed at the right corner of the upper part of the rear wall 1a. The intake port 23 and the exhaust port 24 are each composed of a large number of small holes and communicate with the outside of the storage. An intake fan device 25 (shown only in FIG. 2) for actively taking in outside air is provided on the intake port 23 side. When the intake fan device 25 is driven, air outside the chamber is supplied into the cooking chamber 1 from the air inlet 23, and air in the cooking chamber 1 is discharged outside the chamber from the exhaust port 24. Become.

  Now, in the right front part of the ceiling wall 1b of the cooking chamber 1, a plurality of, in this case, two (first and second) thermistors 26, as the temperature detecting elements in the cooking chamber 1, are detected. 27 is provided. Accordingly, the first and second thermistors 26 and 27 are disposed on a surface (ceiling wall 1 b) different from the left side wall 1 d that is a steam supply surface to the cooking chamber 1 of the steam supply device 10.

  The first and second thermistors 26 and 27 have different detection temperature characteristics. FIGS. 3A and 3B show the relationship between the temperature and resistance value of the first and second thermistors 26 and 27. The following can be seen from these figures. The first thermistor 26 has a small difference between the upper limit value and the lower limit value of the resistance value in a relatively low temperature range of 20 to 100 ° C., and the detection accuracy in the relatively low temperature range is excellent, but is 120 ° C. or higher. However, the difference between the upper limit value and the lower limit value of the resistance value gradually increases, and the detection accuracy in a relatively high temperature range tends to deteriorate. On the other hand, the second thermistor 27 has a small difference between the upper limit value and the lower limit value of the resistance value in a relatively high temperature range of 100 ° C. or higher, and the detection accuracy in a relatively high temperature range is excellent. In a relatively low temperature range of 100 ° C. or lower, the difference between the upper limit value and the lower limit value of the resistance value gradually increases, and the detection accuracy in a relatively high temperature range tends to deteriorate.

  FIG. 2 schematically shows an electrical configuration of a portion related to the gist of the present invention in the cooking device. In FIG. 2, the control device 28 is mainly composed of a microcomputer and functions as a control means for electrically controlling the cooking device. The control device 28 includes an operation unit 29 provided on an operation panel (not shown), a steam thermistor 17 that detects the temperature in the evaporation container 13, and first and second thermistors 26 that detect the temperature in the cooking chamber 1. , 27 are input. The first and second thermistors 26 and 27 are respectively connected in series with the corresponding fixed resistors 30 and 31 between the power source and the ground, and the intermediate point between the first thermistor 26 and the fixed resistor 30, and An intermediate point between the second thermistor 26 and the fixed resistor 31 is connected to the control device 28. In this case, as the temperature in the cooking chamber 1 changes, the resistance values of the first and second thermistors 26 and 27 change, and the voltage value input to the control device 28 changes accordingly. The control device 28 determines the temperature in the cooking chamber 1 based on the input voltage value and a previously prepared table.

  The control device 28 includes a display unit 32 and an upper heater 7 provided on the operation panel based on signals from the operation unit 29, the thermistor 17 for steam, the first and second thermistors 26 and 27, and a control program prepared in advance. , The lower heater 8, the outer hot air heater 2, the inner hot air heater 3, the circulation fan device 4, the steam upper heater 14, the steam lower heater 15, the water supply pump 19, the intake fan device 25, and the like. Yes.

  Next, the operation of the cooking device configured as described above will be described. Here, a case where cooking is performed using steam will be described. Cooking menus using steam include, for example, “chicken teriyaki”, “hamburger”, “chawanmushi”, “warming rice and meat buns”, “cooking that can increase vitamin C such as vegetables” (hereinafter “ "Vitamin C increased cooking"). Of the cooking menus that use steam, “Chicken Teriyaki” and “Hamburg”, etc., correspond to the steam cooking mode at a high temperature of 100 ° C. or higher, which is the boiling point of water. “Warm rice, meat buns, etc.”, “Vitamin C increased cooking”, etc., correspond to low temperature steam cooking where the internal temperature is less than 100 ° C.

  Before starting steam cooking, the user sets the mounting table 21 in the cooking chamber 1 and mounts an object to be cooked (not shown) on the mounting table 21. And in the operation part 29, one of the cooking menus using steam is selected and set. The control device 28 performs cooking using steam based on the input signal of the operation unit 29. FIG. 4 shows a simple flowchart at this time. First, the control device 28 determines whether or not the set temperature (internal temperature) of the selected cooking menu is less than 100 ° C. (step S1).

  Here, when the selected cooking menu is, for example, “chicken teriyaki”, this “chicken teriyaki” corresponds to a steam cooking mode at a high temperature of 100 ° C. or higher, and therefore, according to “NO”, step S2 And go to high temperature steam cooking mode. In the high temperature steam cooking mode, the following control is performed. In this high temperature steam cooking mode, temperature control is performed using the second thermistor 27 suitable for high temperatures.

(High temperature steam cooking mode)
In the high temperature steam cooking mode, first, the outer hot air heater 2 and the inner hot air heater 3 are energized and the circulation fan device 4 is driven. The circulation fan device 4 is driven at a steady rotational speed. Thereby, the hot air heated with the outer side hot air heater 2 and the inner side hot air heater 3 circulates through the cooking chamber 1, and the inside of the cooking chamber 1 is heated. The ventilation fan device 25 for ventilation is driven at a lower rotational speed than the steady rotational speed. Along with this, a small amount of outside air is introduced into the cooking chamber 1 from the intake port 23, and a small amount of inside air corresponding to this is discharged from the exhaust port 24 to the outside. Therefore, the ventilation in the storage is performed at a low level.

  Further, the water supply pump 19 of the steam supply device 10 is driven to supply the water in the water storage tank 18 into the evaporation container 13, and the steam upper heater 14 and the steam lower heater 15 are energized to generate heat. Thereby, the water supplied into the evaporation container 13 is heated to generate steam, and the steam is supplied into the cooking chamber 1 from the steam discharge port 16. At this time, the steam generation temperature is controlled to be 100 ° C. or higher.

  In this way, steam is supplied into the cooking chamber 1, and the hot air is circulated in the cooking chamber 1 as described above. Steam is also circulated along with the hot air, and the steam is also outside the hot air heater 2 and the inner side. The hot air heater 3 is repeatedly heated. For this reason, the steam in the cooking chamber 1 is generated as superheated steam heated to the saturation temperature or higher, and can be set to a high temperature of 300 ° C., for example. The control device 28 detects the temperature in the cooking chamber 1 with the second thermistor 27, and the temperature in the cooking chamber 1 is maintained at a set temperature corresponding to the cooking menu. The heater 3, the steam upper heater 14, the steam lower heater 15, the water supply pump 19, and the like are controlled. Thereby, the cooking by the high temperature superheated steam is performed.

  At this time, the control device 28 compares the temperature detected by the second thermistor 27 with the set temperature of cooking, and the larger the difference is (the higher the detected temperature is lower than the set temperature), the more the internal heating means. The energizing time of the outer hot air heater 2 and the inner hot air heater 3 is lengthened. Conversely, the smaller the difference is, the shorter the energizing time of the outer hot air heater 2 and the inner hot air heater 3 is. FIG. 5 shows an example of the relationship between the data difference (difference between the detected temperature and the set temperature) and the ON time of the hot air heaters (the outer hot air heater 2 and the inner hot air heater 3). For example, when the data difference is 20 ° C. or more, the outer hot air heater 2 and the inner hot air heater 3 are turned on for 24 seconds in 30 seconds, and when the data difference is 6 to 10 ° C., the outer hot air heater 2 and The inner hot air heater 3 is controlled to be turned on for 5 seconds in 30 seconds, and when the data difference is 0 ° C., the outer hot air heater 2 and the inner hot air heater 3 are disconnected. By controlling in this way, the inside of the cooking chamber 1 can be quickly heated to the set temperature, and overheating can be prevented as much as possible.

  Here, in FIG. 6, the characteristic diagram of the 1st thermistor 26 and the 2nd thermistor 27 which detect the temperature in the cooking chamber 1 is shown. In FIG. 6, the horizontal axis represents the internal temperature T (° C.), and the vertical axis represents the detection error temperature ΔT (° C.). As can be seen from FIG. 6, the second thermistor 26 tends to have a smaller detection error as the internal temperature increases, and is suitable for detecting a relatively high temperature of 100 ° C. or higher. Recognize. In steam cooking at a high temperature of 100 ° C. or higher, superheated steam is involved, so the temperature in the cooking cabinet 1 reaches 200 ° C. or higher. Therefore, accurate temperature control is possible by using the second thermistor 27 having high temperature detection accuracy around 200 ° C. The second thermistor 27 has a detection error of about 3 ° C. around 200 ° C.

  In contrast, when the selected cooking menu is, for example, “vitamin C increased cooking” (for example, cooking suitable for increasing vitamin C in spinach), this “vitamin C increased cooking” is 100 ° C. Therefore, the process proceeds to step S3 according to “YES” in step S1, and the low temperature steam cooking mode is executed. In the low temperature steam cooking mode, the following control is performed. In this low temperature steam cooking mode, temperature control is performed using the first thermistor 26 suitable for low temperatures.

(Low temperature steam cooking mode)
First, the inner hot air heater 3 is energized, and the circulation fan device 4 is driven at a rotational speed lower than the steady rotational speed. At this time, of the two hot air heaters 2 and 3, the outer hot air heater 3 is not energized, and only the inner hot air heater 3 is energized, thereby suppressing heating in the cooking chamber 1. In addition, by driving the circulation fan device 4 at a rotational speed lower than the steady rotational speed, the air in the cooking cabinet 1 circulates gently.

  The intake fan device 25 for ventilation is driven at a steady rotational speed. Along with this, air having a relatively low temperature outside the chamber is actively taken into the cooking chamber 1 from the intake port 23, and a corresponding amount of the chamber air is discharged from the exhaust port 24 to the outside of the chamber. . Therefore, the inside of the cabinet is actively ventilated, and the temperature rise in the cooking cabinet 1 is suppressed.

  Then, the water supply pump 19 of the steam supply device 10 is driven to intermittently supply the water in the water storage tank 18 into the evaporation container 13, and the steam upper heater 14 and the steam lower heater 15 are energized to generate heat. Thus, the detection temperature of the thermistor for steam 17 is controlled to be maintained at 120 ° C. Thereby, the water supplied into the evaporation container 13 is heated and steam is instantaneously generated, and the steam is supplied into the cooking chamber 1 from the steam discharge port 16.

  Thus, relatively low-temperature steam is supplied into the cooking chamber 1, and the circulation fan device 4 is rotated at a low speed, so that the steam is agitated by weak circulation air. At this time, the control device 28 detects the temperature in the cooking chamber 1 by the first thermistor 27 and maintains the temperature in the cooking chamber 1 at a set temperature, for example, 40 ° C. The upper heater 14 for steam, the lower heater 15 for steam, the feed water pump 19 and the like are controlled. As a result, cooking by low temperature steam is performed.

  At this time, the control device 28 compares the temperature detected by the first thermistor 26 with the set temperature of cooking, and the larger the difference is (the higher the detected temperature is lower than the set temperature), the more inside heating means. The energizing time of the inner hot air heater 3 is lengthened, and conversely, the smaller the difference is, the shorter the energizing time of the inner hot air heater 3 is. At this time, the same control as in FIG. 5 is performed.

  Here, as can be seen from FIG. 6, the first thermistor 26 has a small detection error at a relatively low temperature of 100 ° C. or less, and the detection error is particularly 1 ° C. or less in the vicinity of 40 to 50 ° C. It can be seen that it is suitable for detecting a temperature of 100 ° C. or lower. Experiments have shown that the set temperature for low temperature steam cooking, especially cooking that increases vitamin C in spinach, needs to be maintained in the 40 ° C temperature range. By using a good first thermistor 26, accurate temperature control can be achieved.

  If the second thermistor 27 is used for low-temperature steam cooking, the detection error of 7 ° C will increase and the vitamin C will increase at the set temperature (internal temperature) 40 ° C for spinach vitamin C increased cooking. However, according to the present embodiment, it is possible to eliminate such inconvenience.

  As described above, according to the present embodiment, the first and second thermistors 26 and 27 having different detected temperature characteristics are used optimally according to the set temperature in the cooking cabinet 1 by utilizing the characteristics. Therefore, even a cooking device that cooks in a high temperature range is used in combination with cooking, such as low-temperature steam cooking, that must be maintained under a temperature of less than 100 ° C. with accurate heating control. be able to. Therefore, temperature control can be performed more precisely in a wide temperature range from a relatively low temperature to a high temperature.

  Since the first and second thermistors 26 and 27 are arranged in the right front portion of the ceiling wall 1b different from the left side wall 1d which is the steam supply surface to the cooking chamber 1 of the steam supply device 10 in the cooking chamber 1, These first and second thermistors 26 and 27 are not easily affected by steam, and temperature detection with high accuracy is possible.

  During heating cooking, the outer hot air heater 2 that heats the cooking chamber 1 is larger as the difference between the detected temperature of the first and second thermistors 26 and 27 that detect the temperature in the cooking chamber 1 and the set temperature of cooking is larger. The energizing time of the inner hot air heater 3 is lengthened, and conversely, the smaller the difference is, the shorter the energizing time of the outer hot air heater 2 and the inner hot air heater 3 is controlled. Can be heated quickly, and overheating can be prevented as much as possible.

The present invention is not limited to the above-described embodiment, and can be modified or expanded as follows.
At the time of steam cooking, the upper heater 7 and the lower heater 8 may be used instead of using the hot air heaters 2 and 3 as the inside heating means for heating the inside of the cooking chamber 1.

The front view of the cooking chamber which shows roughly the main composition of one embodiment of the present invention The figure which shows the electrical constitution of the principal part relevant to this invention (A) is a figure which shows the relationship between the temperature and resistance value of a 1st thermistor, (b) is a figure which shows the relationship between the temperature and resistance value of a 2nd thermistor. Steam cooking flowchart Diagram showing the relationship between data difference (difference between detected temperature and set temperature) and hot air heater on time Characteristic diagram of first and second thermistors

Explanation of symbols

  In the drawings, 1 is a cooking chamber, 2 is an outer hot air heater (inside heating means), 3 is an inner hot air heater (inside heating means), 4 is a circulation fan device, 7 is an upper heater (inside heating means), 8 is a lower heater (internal heating means), 10 is a steam supply device (steam supply means), 11 is an evaporation unit, 12 is a water supply unit, 26 is a first thermistor (internal temperature detection element), and 27 is a second. , A thermistor (internal temperature detection element) 28 indicates a control device (control means).

Claims (4)

A cooking chamber for storing the food,
An internal heating means for heating the inside of the cooking chamber;
Steam supply means for supplying steam into the cooking chamber;
An internal temperature detection element for detecting the temperature in the cooking chamber;
Control means for controlling the internal heating means and the steam supply means based on the detected temperature of the internal temperature detection element,
2. The cooking device according to claim 1, wherein the inside temperature detection element is provided with a plurality of different detection temperature characteristics.   2. The heating according to claim 1, wherein the plurality of internal temperature detecting elements are arranged on a surface different from a steam supply surface to the cooking chamber of the steam supply unit in the cooking chamber. Cooking device.   The control means selects a suitable one from the plurality of internal temperature detection elements according to the set temperature of cooking, and the internal heating means based on the detected temperature of the selected internal temperature detection element The heating cooker according to claim 1 or 2, wherein the steam supply means is controlled.   The said control means lengthens the energization time of the said heating means in a warehouse, so that the difference between the detection temperature of the said internal temperature detection element and the preset temperature of cooking is large at the time of cooking. The cooking device according to any one of 3 above.

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