JP2005016788A - Heating cooker - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a control means for avoiding overheat when cooking foods with microwave heat. <P>SOLUTION: This heating cooker comprises an infrared sensor 22 for detecting the temperature of a food, a thermistor 21 for detecting an atmospheric temperature in the cooker, and the control means for controlling a microwave heating means in accordance with these temperature detection signals. When the result of the temperature detected by one of the infrared sensor 22 and the thermistor 21 shows a preset value during heating cooking with the heating means, the control means receives the detection signal and controls the completion of heating cooking. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a cooking device provided with a high-frequency heating means for cooking food and a non-contact food temperature sensor.
[0002]
[Prior art]
Conventionally, in a heating cooker provided with heating means different from high-frequency heating by a magnetron and heater heating by an oven heater, an infrared sensor is used as a non-contact type temperature sensor that detects the temperature of food during cooking by high-frequency heating. In the case of heater heating, temperature control is performed using a thermistor as an in-chamber temperature sensor for detecting the atmospheric temperature in the heating chamber, and control means for controlling heating cooking based on these detection signals is provided. . In addition, the inner bottom of the heating chamber is equipped with a turntable for placing food, and a weight sensor for detecting the weight of the food is mounted via the table, so that the longest heating time according to the amount of food is provided. Control means that can be set and prevents the food from being overheated is employed.
[0003]
However, in recent years, a configuration without the above-described turntable is desired, and a mechanism (such as a turntable) protruding into the so-called heating chamber is eliminated, and the food placing surface is flattened over the entire bottom of the chamber and cleaned. Ease of use and food installation area can be expanded and handling is also improved. While obtaining such convenience, it is difficult to construct a weight sensor that measures the weight of food through the above-described turntable. Therefore, in this configuration, the temperature of food during cooking is detected. The heating is controlled based on the infrared sensor.
[0004]
As described above, in the heating control means using the infrared sensor, accurate temperature detection by the infrared sensor is required. Of course, if food is not placed in the field of view that can detect infrared rays, proper temperature detection cannot be performed and the set temperature is detected. When cooking is not possible, cooking is performed for a long time, and the food becomes overheated, which wastes the food.
Therefore, in order to secure the detection field of view by the infrared sensor over a wide area, a driving means such as a stepping motor for moving the infrared sensor is provided, so that the food can be cooked well so that the food does not deviate from the detection field of view as much as possible. (For example, refer to Patent Document 1).
[0005]
[Patent Document 1]
JP 2002-13743 A (page 8, FIG. 9)
[0006]
[Problems to be solved by the invention]
However, even if the above measures are taken, it may be difficult to completely set the food installation area in the infrared visual field range, and depending on the cooking state of the food even if it is installed and accommodated within the provisional visual field range. The case where overheating as described above cannot be avoided is predicted. For example, if there is a small amount of food in a tall container, or if the food is contained in a covered container, or if the food is wrapped in wraps or kitchen paper, or if the food is particularly large This is because the non-contact type temperature detecting means cannot accurately detect the surface temperature of the food in the case of a food that generates the steam. Therefore, in such a case, it is impossible to detect a predetermined temperature required for the preset cooking, or even if it can be done, it takes a long time, so it is overheated and the food is dried and wasted. It causes troubles such as simmering or spilling broth.
[0007]
SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and therefore the object thereof is to provide a cooking device provided with a control means capable of avoiding overheating of food when the temperature of the food is detected by a non-contact type food temperature sensor. There is.
[0008]
[Means for Solving the Problems]
In order to achieve the above object, a heating cooker according to the present invention comprises a heating means capable of high-frequency heating and heater heating of food stored in a heating chamber, and a non-contact type food temperature sensor for detecting the temperature of the food. And an internal temperature sensor for detecting the atmospheric temperature in the heating chamber, and a control means for controlling the heating means based on detection signals of these temperature sensors, wherein the control means is based on the high-frequency heating means At the time of cooking, when the temperature detection result of either the food temperature sensor or the internal temperature sensor detects a predetermined value set in advance, the cooking is terminated upon receipt of the detection signal. (Invention of claim 1)
[0009]
According to such a configuration, cooking by using different temperature detection functions of the two sensors can be controlled, and a wide range of heating control with increased reliability is possible.
[0010]
And the thing of Claim 1 WHEREIN: The predetermined value of the temperature sensor in a store | warehouse | chamber was set based on the temperature rise rate in a store | chamber (invention of Claim 2), It is characterized by the above-mentioned.
[0011]
According to such a configuration, heating cooking can be controlled based on temperature detection utilizing the characteristics of the internal temperature sensor, and is particularly effective as a control means for avoiding overheating.
[0012]
Further, in the first aspect of the present invention, the predetermined value of the internal temperature sensor is set based on a temperature increase amount with respect to the initial temperature in the internal storage (invention of claim 3).
[0013]
According to such a configuration, the same effect as that of the second aspect of the invention can be obtained under other different setting conditions.
[0014]
Moreover, in the thing of Claim 1, the predetermined value of the temperature sensor in a store | warehouse | chamber was set based on the temperature change rate in a store | chamber (Invention of Claim 4), It is characterized by the above-mentioned.
[0015]
According to such a configuration, the same effects as those of the second and third aspects of the invention can be obtained under different setting conditions.
[0016]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, one embodiment showing a heating cooker of the present invention will be described with reference to FIGS.
First, the overall configuration of the heating cooker will be briefly described with reference to FIGS. 1 to 3. In the rectangular box-shaped main body case 1 that forms the outer shell, a rectangular container-shaped heating chamber 2 that opens to the front is provided. A machine room 3 surrounded by a body case 1 is formed on the right side adjacent to the heating chamber 2, and includes a magnetron 4 as a heating means, an inverter device 5 (see FIG. 4) not shown, and a cooling fan (see FIG. 4). Only the cooling fan motor 6 is shown), and an infrared sensor 22 and the like to be described later are disposed. The cooling fan is partly supplied to the inside of the heating cabinet 2 together with cooling of the magnetron 4 and the like, and is used for ventilation in the cabinet in order to discharge steam etc. from food.
[0017]
And in the front of the machine room 3 constituting the front surface of the main body case 1, as shown in FIG. 2, an operation panel 7 for performing various input operations for selecting and setting cooking menus and starting cooking is provided. On the other hand, a door 8 that opens and closes the front opening of the heating chamber 2 is rotatably provided. Among them, a circuit board 9 (see FIG. 4) on which various electrical components are mounted is disposed on the back surface of the operation panel 7. The circuit board 9 includes an LCD 10 (corresponding to a display unit), LED A group 11 and a switch group 12 (both of which are shown in FIG. 4) are provided. Corresponding to these, the operation panel 7 is provided with a transparent LCD display unit 13, a switch operation unit 14 also used as an LED display unit, and the like. It has been. Further, the operation panel 7 is provided with a dial 15 that also serves as a start key that can set the cooking time and cooking temperature as required.
[0018]
As shown in FIG. 1, the magnetron 4 is connected in communication with an excitation port 2a formed at the bottom of the heating chamber 2 via a waveguide 16, and the heating is performed on the bottom through a small space. A substantial bottom plate 17 of the storage 2 is disposed. The bottom plate 17 is made of a material that can transmit high-frequency waves from below, such as glass or ceramics, and has a flat surface on which a food (not shown) is placed.
[0019]
Further, a space below the bottom plate 17 is provided with a lower heater 18b made of, for example, a sheathed heater as an oven heater 18, and a rotating antenna 19 for reflecting and stirring high frequencies. The rotating antenna 19 is driven to rotate by an antenna motor 20 provided on the outer bottom so that a high frequency from the excitation port 2 a can be effectively supplied into the upper heating chamber 2.
[0020]
On the other hand, in the upper part of the heating chamber 2, an upper heater 18a constituting the oven heater 18 is provided along the ceiling surface. Further, a thermistor 21 is provided as an internal temperature sensor for detecting the atmospheric temperature in the heating chamber 2, and its function will be described later. Further, the above-described infrared sensor 22 is disposed on the upper right side wall of the heating chamber 2. This infrared sensor 22 is a so-called non-contact type food temperature sensor that catches infrared rays from food installed on the bottom plate 17 of the refrigerator, and cooking is performed by a control means described later based on a detection signal from the infrared sensor 22. Heating control is performed according to the menu.
[0021]
However, the infrared sensor 22 is disposed in a sensor duct 23 provided through the side wall so as to face the inside of the heating chamber 2 as shown in FIG. 3 and is driven by a stepping motor 24 (see FIG. 1) as a driving means. It is configured to be able to swing in the direction of arrow P1 shown in FIG. However, although the infrared sensor 22 is not illustrated, for example, eight infrared detection elements are linearly arranged, and the detection visual fields A1 to A8 by the respective elements projected on the bottom plate 17 shown in FIG. Are provided so as to occupy a linear region over substantially the entire length in the left-right width direction.
[0022]
Therefore, when the infrared sensor 22 is swung in the direction of arrow P1 by the stepping motor 24, the detection visual fields A1 to A8 also reciprocate on the bottom plate 17 in the direction of arrow P2 (front direction in the figure). As a result, almost the entire area excluding a part below the right side wall on the bottom plate 17 on which food (not shown) is placed is set as a visual field that can be detected by the infrared sensor 22.
In addition, on both side walls of the heating chamber 2, a plurality of steps 2b are provided in the upper and lower stages to serve as support means when using a square dish (not shown), and a porous air hole 2c is provided on the right side wall for heating. A part of the air can be blown into the cabinet 2 by the cooling fan described above.
[0023]
FIG. 4 is a block diagram showing a schematic electrical configuration of the cooking device. The control circuit 25 is composed mainly of a microcomputer and includes a memory such as a CPU, a ROM, and a RAM. The memory stores a control program executed by the microcomputer, and receives the following input signals and the like. It functions as a control means for controlling the overall operation of the cooking device.
[0024]
Detection signals from the thermistor 21 and the infrared sensor 22 are input to the control circuit 25 via the thermistor interface 26 and the infrared sensor interface 27. Further, the pulse signal of the encoder 28 and the switch signal of the switch group 12 are input to the control circuit 25 via the interfaces 29 and 30, respectively. The encoder 28 outputs a rotation amount of the dial 15 by a pulse signal.
[0025]
The control circuit 25 controls the drive of the magnetron 4 via the inverter interface 31 and the inverter device 5. Further, the control circuit 25 includes an oven heater 18 including upper and lower heaters 18a and 18b, a cooling fan motor 6, a stepping motor 24, a buzzer 32, the LCD 10, the LED group 11, and the antenna motor 20, respectively, a heater driving circuit 33 and a fan interface 34. Control is performed via a stepping motor interface 35, a buzzer driving circuit 36, an LCD driving circuit 37, an LED driving circuit 38, and a rotating antenna interface 39.
[0026]
Here, the function of the thermistor 21 for detecting the above-described inside temperature will be described. This normally functions as an inside temperature sensor during cooking using the oven heater 18 and is set according to a so-called cooking menu. The internal temperature is detected to obtain the temperature, and the oven heater 18 is heated based on the detection result. However, the control means in the present embodiment is provided with a control function capable of avoiding the food from being overheated in addition to the heating control using the infrared sensor 22 when the magnetron 4 is cooked by high frequency heating.
[0027]
That is, the infrared sensor 22 detects the temperature of the food that is normally cooked, and when this reaches a preset temperature that is a predetermined value stored in advance, the control circuit 25 receives the detection signal and controls to end the cooking. . However, with this non-contact type infrared sensor 22, the true temperature cannot be accurately detected when the food is cooked, for example, when a large amount of steam is generated and filled, and in this case, heating is performed without reaching the set temperature. As described above, cooking is performed for a long time and reaches an overheated state.
[0028]
Therefore, in this embodiment, in order to avoid overheating of the food, a plurality of countermeasures that effectively use the thermistor 21 are employed.
5 to 7 show measured values of the temperature detected by the infrared sensor 22 and the thermistor 21, and particularly show temperature characteristics for explaining the means for avoiding overheating by focusing on different phenomena. Therefore, as shown in these drawings, the food temperature detected by the infrared sensor 22 approaches the preset temperature T ₀ stored in advance, but the detected food temperature approaches as the cooking time elapses. _A state where the temperature does not reach ₀ and an appropriate temperature cannot be detected, or an abnormal state that requires more time to detect is shown, and the reason will be described below.
[0029]
First, FIG. 5 shows the first avoiding means. That is, the inside temperature detected by the thermistor 21 after cooking proceeds equivalent time t ₁ has elapsed, shows a steep increase in temperature until the time t ₂ (temperature detected R ₁ → R _2). In this phenomenon, when the food is heated to a certain temperature, the generation of steam suddenly becomes active (time t ₁ ), and in this example, the internal temperature detected by the thermistor 21 suddenly increases. This has also been confirmed from the fact that the thermistor 21 itself is warmed by the latent heat (condensation heat) of the full steam and shows a rapid temperature rise. Therefore, in the infrared sensor 22, such a sudden generation and increase of steam exceeds the ventilation capacity of the inside of the refrigerator by the cooling fan, and the filled steam hinders detection of the surface temperature of the food and the true temperature is detected. In other words, the so-called pre-stored set temperature T ₀ cannot be detected, or even if it can, it takes a longer time.
[0030]
Therefore, paying attention to the abrupt temperature rise described above, when temperature detection is performed with an increase rate R (b / a) exceeding the temperature increase rate R ₀ as a predetermined value stored in advance (for example, time t ₂ time) can be avoided excessive heating of the food if to terminate the cooking as has reached a predetermined value. Thus, as a first avoiding means, when the temperature rise rate R accompanying the detection of the internal temperature of the thermistor 21 reaches a predetermined value R ₀ , the control signal is input. Via the circuit 25, it controls so that the magnetron 4 which is a heating means may be de-energized and cooking is completed.
[0031]
On the other hand, the second avoidance means shown in FIG. 6 is made by paying attention to a phenomenon different from the above, and the change in the internal temperature by the thermistor 21 gradually increases and shows a gentle temperature gradient. Yes. Such a phenomenon is an example in which the steam emitted from the food gradually increases from the initial stage of heating. In this case as well, the infrared sensor 22 fills the heating chamber 2 with steam in the latter half of the cooking. Similarly to the above, the set temperature of the infrared sensor 22 cannot be detected.
[0032]
Therefore, in such a case, a temperature increase amount ΔM (= M ₂ −M ₁ ), which is a temperature difference between the initial temperature M ₁ in the refrigerator and the subsequent detected temperature M ₂ , is obtained, and this temperature increase amount is stored in advance. When the temperature is detected to have reached the predetermined temperature rise amount M ₀ or more (for example, time t ₁ ), overheating of the food can be avoided by terminating the cooking.
[0033]
Then, the third avoiding means will be described with reference to FIG. 7. From this figure, the detected temperature of the food by the infrared sensor 22 shows a state in which the true temperature cannot be detected due to the presence of steam as described above. The detection result of the internal temperature by 21 is represented by a temporal change by a differential signal as a temperature change rate. This indicates “fluctuation” of the detection signal due to contact with the thermistor 21 as the detection temperature increases particularly with the generation of steam, and the output signal of the thermistor 21 is combined with, for example, a capacitor (not shown). This signal can be easily obtained by amplification. Therefore, in the third avoiding means, when the differential signal A of the output of the thermistor 21 reaches a predetermined value equal to or higher than the predetermined reference level A ₀ (time t ₁ time), the cooking is performed. By controlling the termination, overheating of the food can be avoided.
[0034]
Next, the operation of the heating cooker having the above configuration will be described. FIG. 8 is a flowchart showing the control contents executed by the control circuit 25 including the operation procedure, and will be described along this flow.
For example, in order to cook hotly after the power is turned on, food (not shown) is accommodated and installed on the bottom plate 17 in the heating chamber 2 (step S1), and the cooking setting corresponding to the cooking menu is performed on the operation panel 7 (step S2). ). Thereby, the set temperature which is also the finishing temperature of the food by the infrared sensor 22 is determined.
[0035]
Then, the magnetron 4 serving as a heating means is energized and driven by a start key operation, oscillates a high frequency and is supplied from below into the heating chamber 2, and heating cooking (warming cooking) of the food on the bottom plate 17 is started (step) S3). With the start of cooking, the temperature of the food is detected by the infrared sensor 22 (step S4), and the infrared sensor 22 swung by the stepping motor 24 is substantially on the bottom plate 17 as shown in FIG. Using the entire area as the detection field of view, the temperature of the food placed in this area is detected.
[0036]
Then, the detected temperature T is compared determine reaches the set temperature T ₀ which is above (step S5), and respectively on the basis of the determination "YES" or "NO", control is passed to the next step. Hereinafter, a case where cooking is normally performed without any abnormality in the cooking state of the food will be described.
Accordingly, the determination by the step S5, the heating initially not reach the set temperature T ₀ of course the decision is "NO", the inside temperature according migrated thermistor 21 to the next step S6 is detected.
[0037]
The detection result of the internal temperature by the thermistor 21 is effective only when the abnormal cooking state described in the following steps S7 to S9 (see FIGS. 5 to 7) is reached. Also, based on the “NO” determination, the process returns to step S4. The food temperature T by the infrared sensor 22 in the step S4 is repeatedly detected, which is continued until reaching the set temperature T ₀ which tells the completion of the normal cooking step S5 (YES judgment). Thus to, cooking progresses to reach the set temperature T ₀ at step S5 when it is determined "YES", the immediately oscillation of the magnetron 4 as the migration cooked to step S10 (warm cooking) is finished Stop and control to finish cooking.
[0038]
On the other hand, unlike the normal heating state described above, as described above with reference to FIGS. 5 to 7, when a large amount of steam increases to fill the interior, the set temperature T ₀ by the infrared sensor 22 is increased. Is difficult to detect. For this reason, in step S5 in FIG. 8, the “NO” determination is continuously issued, and cooking is continued. Hereinafter, in the case of such an abnormal state, the following step S6 and subsequent steps will be described.
[0039]
In step S6, the internal temperature by the thermistor 21 is detected as described above, and the process proceeds to step S7. However, in steps S7 to S9, temperature detection is performed when the cooking state is abnormal as described above. First, in step S7, a rapid increase due to the rapid increase in steam as described in FIG. The temperature rise rate R accompanying the temperature rise is monitored, and it is determined whether or not this is greater than or equal to a predetermined value _R0 set in advance. However, in this case as well, since the above phenomenon does not yet occur in the initial stage of the cooking operation, the process proceeds to the next step S8 based on the “NO” determination.
[0040]
In step S8, as described based on FIG. 6, in which the steam gradually occurred corresponding to the filled phenomenon that can no longer be accurate temperature detection within the heating chamber 2, a temperature rise amount to the initial temperature M ₁ It is determined whether ΔM (= M ₂ −M ₁ ) is equal to or greater than a predetermined value M ₀ . In this case, however, if the operation is in the initial stage, the process proceeds to the next step S9 based on the “NO” determination. In step S9, as described with reference to FIG. 7, the differential signal A that responds to the state of steam generation is extracted, and it is determined whether or not the differential signal A has reached a predetermined value _A0 or more. Similarly, in the initial stage of operation, the process returns to step S4 based on the “NO” determination. Therefore, this return is repeatedly performed in the initial stage of cooking, and cooking is continuously performed unless the temperature detection results by the infrared sensor 22 and the thermistor 21 reach predetermined values set respectively.
[0041]
However, in this example, the infrared sensor 22 accompanying the generation of steam cannot proceed with true temperature detection, but the thermistor 21 is a container corresponding to one of the steps S7, S8, and S9. When the internal temperature is detected and the detection result reaches a corresponding predetermined value, the determination of “YES” in the corresponding step is obtained and the process proceeds to step S10. Immediately after that, the magnetron 4 serving as the heating means is deactivated and the cooking is finished. It is made. Therefore, the food being cooked can be finished before it is dried by being overheated or spilled, so that the food is not wasted. In this case, when the buzzer 32 notifies the end of heating in this case, it is preferable to notify the user as ringing control different from the normal end notification.
[0042]
Thus, according to this embodiment, the following effects are obtained.
When food is cooked by high-frequency heating of the magnetron 4 as a heating means, the temperature of the food is detected by the infrared sensor 22, and the temperature inside the chamber can be detected by the thermistor 21. Then, when the temperature detection result by either the infrared sensor 22 or the thermistor 21 reaches a predetermined value set in advance, the end of the cooking is controlled. Therefore, cooking can be controlled with different temperature detection functions using the non-contact type food temperature sensor that detects the former food temperature and the latter temperature sensor that detects the atmosphere temperature in the latter, and reliability is improved accordingly. It is convenient because it can control the increased heating.
[0043]
Specifically, the infrared sensor 22 detects the set temperature at which the original cooking of the food is finished. The infrared sensor 22 detects the true temperature according to the cooking state of the food. In an abnormal state that is difficult to perform, the temperature detection by the thermistor 21 is validated, and when the detection result reaches a predetermined value set in advance, the detection signal is received and the cooking is performed via the control circuit 25. The control was terminated. Thereby, when it becomes impossible to detect an appropriate temperature by the infrared sensor 22, the cooking can be terminated based on the detection result by the thermistor 21, so that the food can be avoided from being overheated and not wasted. .
[0044]
In addition, as shown in the present embodiment, the thermistor 21 also controls the temperature required to maintain the temperature required for cooking when the heater is heated by the oven heater 18 (upper and lower heaters 18a and 18b), which is a heating means. The thermistor 21 provided in this type of cooking device can be used skillfully, and can be manufactured without complicating the structure and assembly, which is advantageous in terms of cost.
Thus, there is provided a cooking device that can eliminate the anxiety of the temperature detection means by the infrared sensor 22 and can fully utilize the convenience of omitting the conventional weight sensor and making the food installation area the flat bottom plate 17. it can.
[0045]
The present invention is not limited to the embodiment described above and shown in the drawings. For example, the heating heater is arranged at the upper and lower portions of the heating chamber, but the upper heater alone may be used. Even in the case of high-frequency heating as one heating means, it is not limited to supplying high-frequency from the lower side of the heating chamber, and may be configured to irradiate from the side or from the upper side. It can be implemented with appropriate modifications.
[0046]
【The invention's effect】
As is apparent from the above description, the cooking device of the present invention includes a non-contact type food temperature sensor that detects the temperature of food, an internal temperature sensor that detects the internal atmosphere temperature, and the temperature sensor. The control means includes a control means for controlling the high-frequency heating means based on the detection signal, and the control means has a temperature detection result of one of the food temperature sensor and the internal temperature sensor during cooking by the high-frequency heating means. When a predetermined value set in advance is detected, the cooking is ended upon receipt of the detection signal.
This makes it possible to control cooking by using the different temperature detection functions of the above two temperature sensors, and can control a wide range of heating with increased reliability, and can be manufactured without complicating configuration and assembly. A cooking device suitable for the above can be provided.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view showing a schematic configuration of an entire heating cooker according to an embodiment of the present invention. FIG. 2 is an external perspective view. FIG. 3 is an enlarged perspective view of a main part. FIG. 5 is a temperature characteristic diagram for explaining a phenomenon during cooking. FIG. 6 is a view corresponding to FIG. 5 for explaining a different phenomenon. FIG. 7 is a diagram for explaining a further different phenomenon. Equivalent figure [Fig. 8] Flow chart showing the contents of control of cooking [Explanation of symbols]
1 is a housing, 2 is a heating chamber, 4 is a magnetron (heating means), 17 is a bottom plate, 18 is an oven heater (heating means), 21 is a thermistor (internal temperature sensor), 22 is an infrared sensor (food temperature sensor) And 25 show control circuits (control means).

Claims (4)

Heating means that enables high-frequency heating and heater heating of the food contained in the heating chamber, a non-contact type food temperature sensor that detects the temperature of the food, and an internal temperature sensor that detects the atmospheric temperature in the heating chamber And a control means for controlling the heating means based on detection signals of these temperature sensors,
The control means receives the detection signal when the temperature detection result of either the food temperature sensor or the internal temperature sensor detects a predetermined value during cooking by the high-frequency heating means. The cooking device is characterized in that the cooking is finished. The cooking device according to claim 1, wherein the predetermined value of the internal temperature sensor is set based on a rate of temperature increase in the internal chamber. The cooking device according to claim 1, wherein the predetermined value of the internal temperature sensor is set based on an amount of temperature increase with respect to the initial temperature in the internal storage. 2. The cooking device according to claim 1, wherein the predetermined value of the internal temperature sensor is set based on a rate of temperature change in the internal chamber.

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