JP2017156070A - Heating cooker - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a structure capable of properly maintaining a temperature in a cooking chamber at a preset temperature while generating steam in the cooking chamber, in a heating cooker for generating steam in the cooking chamber.SOLUTION: In a heating cooker, in a state where a fan is actuated, a control device controls the operation of a heater and a water guide valve based on a detection temperature of a temperature sensor, and controls so that hot air including steam is allowed to convect at a preset temperature T in a cooking chamber. The control device controls the output of the heater in such a manner that the temperature in the cooking chamber rises in a range lower than an upper limit temperature Th which is higher than the preset temperature T by a predetermined temperature, and controls an opening of the water guide valve in such a manner that the temperature in the cooking chamber drops in a range higher than a lower limit temperature Tl which is lower than the preset temperature T by a predetermined temperature.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a heating cooker that heats and cooks food by convection of hot air containing steam such as a steam convection oven.

  Patent Document 1 discloses a cooking device that cooks food by convection of hot air containing steam. This cooking device generates steam by evaporating the introduced water in the cooking chamber with a heater that heats the inside of the cooking chamber without providing a steam generator for supplying steam outside the cooking chamber. This cooking device is provided with a cooking chamber for storing ingredients, a centrifugal fan that is provided on the right side of the cooking chamber to convect the air in the cooking chamber, and is provided on the right side of the cooking chamber to heat the cooking chamber. A heater, a water guide pipe for introducing water for generating steam in the cooking chamber, and a water guide valve for opening and closing the water guide pipe are provided. In this heating cooker, the water introduced from the water conduit is blown to the outer heater by the centrifugal force of the blades rotating from the center of the centrifugal fan, and the water blown to the heater is heated to become steam. Steam convects in the cooking chamber together with hot air generated by the centrifugal fan and the heater, and the food in the cooking chamber is cooked by hot air containing steam.

Japanese Patent No. 5186511

  The above-described cooking device of Patent Document 1 includes a hot air mode cooking program that convects hot air from a centrifugal fan and a heater, and a steam mode that convects steam from a heater and a centrifugal fan that are operated with an output that generates steam. It has a cooking program and a combination mode cooking program for convection of hot air containing steam generated by a heater and a centrifugal fan operated with an output that generates hot air in the cooking chamber while generating steam.

  When steam is generated with a high steam amount of 90% at a high temperature of, for example, 200 ° C. or higher in a combination mode cooking program, the water guide valve is opened and water is introduced from the water conduit into the cooker. While controlling, the operation | movement of a heater is controlled so that the inside of a cooking chamber may become preset temperature based on the detection temperature of a temperature sensor. The water supplied into the cooking chamber is blown to the heater and evaporates to become steam. However, since the heater loses latent heat when the water evaporates, the cooking chamber may not be maintained at a high temperature by the heater. If the cooking chamber cannot be maintained at the set temperature, the cooking program will be completed without being properly cooked by cooking even if the set cooking time has elapsed. In order to avoid this, by adopting a valve that can adjust the opening of a proportional control valve or the like for the water guide valve, and by interposing a pressure reducing valve that makes the flow rate constant by making the water supply pressure constant in the water guide pipe, It was also considered to limit the flow rate of water introduced from the conduit. However, even if the flow rate of water introduced from the water conduit is limited, it is difficult to maintain the temperature in the cooking chamber at the set temperature unless the balance between the amount of introduced water and the output of the heater is good. . An object of the present invention is to make it possible to appropriately maintain the temperature in the cooking chamber at the set temperature while generating the steam in the cooking chamber in the cooking device that generates the steam in the cooking chamber.

  In order to solve the above-described problems, the present invention provides a cooking chamber for storing ingredients, a fan provided in one side portion of the cooking chamber for convection of air in the cooking chamber, and a side portion in the cooking chamber. A heater that heats the inside of the cooking chamber, a water conduit that introduces water for generating steam in the cooking chamber, and a water guide valve that is interposed in the water conduit and adjusts the opening of the water conduit And a temperature sensor for detecting the temperature in the cooking chamber, and in a state where the fan is operated, the operation of the heater and the water guide valve is controlled based on the temperature detected by the temperature sensor, and the cooking chamber is set at the set temperature. A heating cooker comprising a control device for convection of hot air containing steam, wherein the control device increases the temperature in the cooking chamber within a range lower than the upper limit temperature that is higher than the set temperature by a predetermined temperature. The heater output is controlled at There is provided a cooking device, characterized in that to control the opening of the water guide valve so as to lower the temperature in the cooking chamber at a high range.

  In the heating cooker configured as described above, the control device controls the output of the heater so as to raise the temperature in the cooking chamber within a range lower than the upper limit temperature that is higher than the set temperature by a predetermined temperature, and the predetermined temperature from the set temperature. The opening degree of the water guide valve is controlled to lower the temperature in the cooking chamber in a range higher than the lower temperature lower limit temperature. The temperature in the cooking chamber is introduced from the water conduit into the cooking chamber by maintaining the temperature within the upper and lower limits of the set temperature by both heating by the heater and cooling by introducing water from the water conduit. Steam is generated by evaporation of water. As a result, it is possible to achieve both maintaining the temperature in the cooking chamber within the temperature range of the upper limit and the lower limit temperature of the set temperature and generating steam in the cooking chamber.

It is a front view of the heating cooker of this invention. It is the schematic of a heating cooker. It is a graph which shows heating-cooling PID control.

  Below, one Embodiment of the heating cooker of this invention is described with reference to an accompanying drawing. The heating cooker of the present invention heats and cooks food by convection with hot air containing steam called a steam convection oven, and heats the food using steam obtained by evaporating water introduced into the cooking cabinet. To do. As shown in FIG. 1, the heating cooker 10 includes a cooking chamber 12 for heating and cooking food in a housing 11. A front opening 12a through which food is taken in and out is provided at the front of the cooking cabinet 12, and a door 13 for opening and closing the front opening 12a is provided at the front opening 12a.

  As shown in FIG. 2, a centrifugal fan (fan) 21 that convects the air in the cooking cabinet 12 is rotatably provided on the left side (one side) of the cooking cabinet 12. The centrifugal fan 21 includes an impeller 22 arranged on the left side in the cooking cabinet 12 and a fan motor 23 arranged on the outside of the cooking cabinet 12. By driving the fan motor 23, the impeller 22 rotates in the cooking chamber 12, and the air in the central part and the right side in the cooking cabinet 12 is sucked into the left side by the rotation of the impeller 22, and the sucked air is impeller. 22 is spouted outward in the centrifugal direction, and the blown air is sent along the upper and lower and front and rear walls of the cooking cabinet 12 to the center and right side of the cooking cabinet 12. Thus, the centrifugal fan 21 convects the air in the cooking cabinet 12.

  A heater 24 for heating the inside of the cooking cabinet 12 is provided on the left side (one side) in the cooking cabinet 12. The heater 24 uses an electric sheathed heater, and is provided in a state of being wound in an annular shape on the left side in the cooking cabinet 12 on the outer side in the centrifugal direction of the impeller 22 of the centrifugal fan 21. As described above, the air in the cooking chamber 12 is convected by the rotation of the impeller 22 of the centrifugal fan 21, and the air blown outward in the centrifugal direction by the rotation of the impeller 22 of the centrifugal fan 21 is Heated when passing around the heater 24, the air in the cooking chamber 12 becomes hot air and convects in the cooking chamber 12.

  A temperature sensor 25 is provided outside the heater 24 on the left side in the cooking cabinet 12, and the temperature sensor 25 detects the temperature in the cooking cabinet 12. An exhaust temperature sensor 26 is provided in the exhaust path 14 of the cooking chamber 12, and the exhaust temperature sensor 26 is used to calculate the amount of steam in the cooking chamber 12 based on the correlation of the temperature detected by the temperature sensor 25. An intake port is provided on the left side wall of the cooking chamber 12, and an intake pipe 27 for introducing outside air from the outside of the housing 11 is connected to the intake port. An intake valve 28 is interposed in the intake pipe 27, and air outside the housing 11 is introduced into the cooking chamber 12 from the intake pipe 27 by opening the intake valve 28. The intake valve 28 is a butterfly valve, and the opening degree of the intake pipe 27 is adjusted by adjusting the rotation angle so that the amount of air introduced into the cooking chamber 12 can be adjusted.

  A water conduit 31 is provided on the left side of the cooking chamber 12 to guide water from a water supply source such as a water supply to the cooking chamber 12, and the water conduit 31 supplies water for generating steam in the cooking chamber 12. Is. Water guided from the water conduit 31 into the cooking chamber 12 is blown by the impeller 22 of the centrifugal fan 21 to the outer heater 24 in the centrifugal direction and the peripheral wall of the cooking chamber 12, and the sprayed water generates heat and the heater 24 and heater. Evaporates into steam by the peripheral wall of the cooking chamber 12 that has absorbed 24 heat. A water guide valve 32 for adjusting the flow rate of water passing through the water guide pipe 31 is interposed in the water guide pipe 31, and a proportional control valve is employed as the water guide valve 32 in this embodiment. The opening degree of the water guide valve 32 is controlled by a signal from an opening degree control unit 42 to be described later, and the flow rate of water in the water guide pipe 31 increases when the water guide valve 32 increases the opening degree. In addition, a pressure reducing valve (not shown) is interposed upstream of the water guiding valve 32 in the water guiding pipe 31, and the water pressure introduced into the water guiding pipe 31 from the water supply source is adjusted to be constant by the pressure reducing valve. Has been.

  The heating cooker 10 includes a control device 40, and the control device 40 is connected to the fan motor 23, the heater 24, the temperature sensor 25, the exhaust temperature sensor 26, the intake valve 28, and the water guide valve 32 of the centrifugal fan 21. . The control device 40 includes a microcomputer (not shown), and the microcomputer includes a CPU, a RAM, a ROM, and a timer (all not shown) connected via a bus.

  The control device 40 includes an output control unit 41 that controls the output of the heater 24, and the output control unit 41 controls the output (heat generation amount) of the heater 24 based on a control signal from the control device 40. In this embodiment, the output control unit 41 employs an SSR (semiconductor relay). In addition, the control device 40 includes an opening degree control unit 42 that controls the opening degree of the water guide valve 32 including a proportional control valve, and the opening degree control unit 42 is based on a control signal from the control device 40. The degree of opening is controlled.

  The control device 40 includes a cooking program for cooking the food in the cooking cabinet 12 in the ROM. The cooking program includes a hot air mode cooking program in which food is heated and cooked by hot air that is convected by operating the centrifugal fan 21 and the heater 24, and food that is generated by steam that is convected by operating the centrifugal fan 21, the heater 24, and the water guide valve 32. Cooking consisting of three modes: a steam mode cooking program for cooking and a combination mode cooking program for cooking food by hot air containing convection steam by operating the centrifugal fan 21, the heater 24 and the water guide valve 32 Has a program. In addition, although the cooking program of each mode is preset with temperature and cooking time, these temperature and cooking time can also be set arbitrarily. In addition, the combination mode cooking program can further set the steam amount.

  The control device 40 controls the output of the heater 24 by PID control so that the inside of the cooking cabinet 12 becomes the set temperature T based on the temperature detected by the temperature sensor 25 when executing each cooking program. In addition, when executing the combination mode cooking program, the control device 40 generates the appropriate amount of steam while maintaining the temperature in the cooking chamber 12 at the set temperature T, and the heater 24 and the heating and cooling PID control. The operation of the water guide valve 32 is controlled. The heating / cooling PID control controls both heating by the heater 24 and cooling by water from the water conduit 31 so that the set temperature T in the cooking chamber 12 is reached. In this heating / cooling PID control, by setting a dead band (dead band) to minus in the temperature range between the upper limit temperature Th and the lower limit temperature Tl across the set temperature T, the upper limit temperature Th and the lower limit across the set temperature T are set. Both heating by the heater 24 and cooling by water from the water conduit 31 are performed simultaneously in a temperature range between the temperature Tl. By controlling in this way, while maintaining the inside of the cooking chamber 12 at the set temperature T, the water from the water conduit 31 is evaporated to generate steam. The heating / cooling PID control will be described in detail below.

  As shown in FIG. 3, when the control device 40 executes the heating / cooling PID control, the cooking chamber 12 is in a range lower than the upper limit temperature Th higher than the set temperature T by a predetermined temperature (the range shown in A of FIG. 3). The output of the heater 24 is controlled so as to increase the temperature inside, and the temperature in the cooking chamber 12 is decreased in a range higher than the lower limit temperature Tl lower than the set temperature T by a predetermined temperature (the range shown in FIG. 3B). The opening degree of the water guide valve 32 is controlled so that At this time, the water introduced into the cooking chamber 12 when the water guide valve 32 is opened is blown to the heater 24 and the peripheral wall of the cooking chamber 12 by the impeller 22 of the centrifugal fan 21 to generate heat and heat of the heater 24 and the heater 24. It is heated by the peripheral wall of the cooking cabinet 12 that has absorbed the gas and evaporated to become steam. In addition, since the temperature in the cooking chamber 12 is not heated higher than the upper limit temperature Th, the water guide valve 32 is hardly opened in a range higher than the upper limit temperature Th. For this reason, the graph which shows the opening degree of the water conveyance valve 32 was made to show the range higher than upper limit temperature Th with a dashed-two dotted line.

  The heating / cooling PID control will be described in more detail. The control device 40 controls the heater 24 to reduce the output of the heater 24 as it approaches the upper limit temperature Th when the set temperature T is lower than the upper limit temperature Th. Is heating the temperature in the cooking chamber 12 to the upper limit temperature Th of the set temperature T. Moreover, the control apparatus 40 is controlling so that the opening degree of the water guide valve 32 is made low as it approaches the lower limit temperature Tl when it is higher than the lower limit temperature Tl of the set temperature T. The water introduced from the water conduit 31 into the cooking chamber 12 reduces the temperature in the cooking chamber 12 to the lower limit of the set temperature T by removing heat and latent heat from the heater 24 and the peripheral wall of the cooking chamber 12 that has absorbed the heat of the heater 24. Cooling is performed so that the temperature becomes Tl. At this time, the water that has taken heat from the heater 24 and the peripheral wall of the cooking cabinet 12 evaporates and becomes steam in the cooking cabinet 12. As described above, the control device 40 controls the output of the heater 24 so as to increase the temperature of the cooking chamber 12 based on the temperature detected by the temperature sensor 25, and introduces water so as to decrease the temperature in the cooking chamber 12. By controlling the opening degree of the valve 32, it is possible to maintain the temperature in the cooking cabinet 12 within the upper and lower limits of the set temperature T and to generate steam in the cooking cabinet 12. Can be achieved.

  Next, the operation of the combination mode cooking program of the heating cooker 10 will be described. The combination mode cooking program is a program for cooking with hot air containing steam that convects ingredients in the cooking chamber 12 by convection of hot air containing steam in the range of 100 ° C. to 300 ° C. as an example in the cooking chamber 12. It is. The control device 40 controls the operation of the heater 24 and the water guide valve 32 by heating / cooling PID control as described above when executing this combination mode cooking program. When the set temperature T in the cooking chamber 12 is set to, for example, 250 ° C. and the steam amount becomes 90% in the combination mode cooking program, the control device 40 cooks while rotating the centrifugal fan 21 as a preheat treatment. The operation of the heater 24 is controlled based on the temperature detected by the temperature sensor 25 so as to raise the temperature in the cabinet 12 to the set temperature T. The air in the cooking chamber 12 is spouted outward in the centrifugal direction by the rotation of the impeller 22 of the centrifugal fan 21, and the spouted air is heated when passing around the heater 24 to become hot air. The temperature in the cooking chamber 12 rises due to the convection hot air. When the temperature in the cooking chamber 12 reaches the set temperature T, the pre-heat treatment is finished, and the heating process for heating and cooking while maintaining the set temperature T for the cooking time in which the food stored in the cooking chamber 12 is set is started.

  The control device 40 approaches the upper limit temperature Th of the set temperature T when the temperature in the cooking cabinet 12 is lower than the upper limit temperature Th of the set temperature T by heating and cooling PID control when the combination mode cooking program is executed. When the temperature in the cooking chamber 12 is higher than the lower limit temperature Tl of the set temperature T, the opening degree of the water guide valve 32 becomes closer to the lower limit temperature Tl of the set temperature T. Is controlled to be smaller. When the heating / cooling PID control is executed, the air in the cooking chamber 12 becomes hot air by the rotation of the centrifugal fan 21 and the heat generated by the heater 24 and convects in the cooking chamber 12. Further, the water introduced into the cooking chamber 12 when the water guide valve 32 is opened is blown to the heater 24 and the peripheral wall of the cooking chamber 12 by the impeller 22 of the centrifugal fan 21, and the heat of the heater 24 and the heater 24 that generate heat is blown. It is heated by the peripheral wall of the absorbed cooking cabinet 12 and evaporated to become steam. The steam convects in the cooking chamber 12 together with hot air generated by the rotation of the centrifugal fan 21 and the heat generated by the heater 24. Ingredients in the cooking cabinet 12 are heated and cooked by the hot air containing the steam. When the steam amount in the cooking chamber 12 is set low, the intake valve 28 may be adjusted so as to open the opening, and the outside air may be introduced into the cooking chamber 12 to reduce the steam amount. As another method, the flow rate of water introduced from the water conduit 31 to the cooking chamber 12 is intentionally reduced by intentionally setting the opening of the water guide valve 32 at the time of the heating / cooling PID control. It may be.

  In the heating cooker 10 configured as described above, the control device 40 controls the output of the heater so as to raise the temperature in the cooking chamber 12 in a range lower than the upper limit temperature Th higher than the set temperature T by a predetermined temperature, The opening degree of the water guide valve 32 is controlled so as to lower the temperature in the cooking chamber 12 in a range higher than the lower limit temperature Tl lower than the set temperature T by a predetermined temperature. The temperature in the cooking chamber 12 is maintained in the temperature range of the upper and lower limit temperatures Th and Tl of the set temperature T by both heating by the heater 24 and cooling by introducing water from the water conduit 31. In the inside, steam is generated by evaporation of water introduced from the water conduit 31. Thereby, even if the set temperature in the cooking chamber 12 is set to a high temperature (for example, 200 ° C. to 300 ° C.) and a large amount of steam (for example, 70% to 90%), the temperature in the cooking chamber 12 is set to the set temperature T. It is now possible to maintain both the upper and lower temperature limits Th and Tl within the temperature range and to generate steam in the cooking cabinet 12.

 DESCRIPTION OF SYMBOLS 10 ... Heat cooker, 12 ... Cooking chamber, 21 ... Fan (centrifugal fan), 24 ... Heater, 25 ... Temperature sensor, 31 ... Water conduit, 32 ... Water guide valve, 40 ... Control apparatus.

Claims (1)

A cooking cabinet containing ingredients,
A fan provided on one side of the cooking chamber to convect the air in the cooking chamber;
A heater provided on one side of the cooking chamber for heating the cooking chamber;
A water conduit that introduces water for generating steam on one side of the cooking chamber;
A water guide valve that is interposed in the water conduit and adjusts the opening of the water conduit;
A temperature sensor for detecting the temperature in the cooking chamber;
In a state where the fan is operated, the operation of the heater and the water guide valve is controlled based on the temperature detected by the temperature sensor so that hot air containing steam is convected in the cooking chamber at a set temperature. A cooking device comprising a control device for controlling
The control device controls the output of the heater to raise the temperature in the cooking chamber within a range lower than an upper limit temperature that is higher than the set temperature by a predetermined temperature, and lower than a lower limit temperature that is lower than the set temperature by a predetermined temperature. A cooking device characterized by controlling the opening degree of the water guide valve so as to lower the temperature in the cooking chamber in a high range.

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