JP7482349B2 - Rice cooker and rice cooking method - Google Patents

Description

This disclosure relates to a rice cooker and a rice cooking method.

In conventional rice cookers, in order to adjust the sweetness, flavor, and hardness of cooked rice and achieve precise cooking, a configuration has been proposed in which a steam sensor detects boiling during the heating process, which starts gelatinization of the food, and then the process moves to the boiling maintenance process. In addition, in conventional rice cookers, a configuration has been proposed in which the process moves to the next process when the steam sensor detects a certain temperature.

JP 2009-50485 A

However, there is still room for improvement in the conventional rice cookers described above in terms of improving the taste of rice.

In the above-mentioned conventional rice cookers, boiling is detected by the steam temperature during the heating process, making it difficult to accurately detect boiling. Therefore, for example, if the process moves to the boiling maintenance process before the water in the pot has completely boiled, the time for the boiling maintenance process is extended, which can cause the rice grains to crumble and deteriorate the taste. Alternatively, if the process moves to the boiling maintenance process when the water in the pot has boiled too much, the moisture content is reduced during the boiling maintenance process, causing the rice grains to crumble and deteriorate the taste.

This disclosure provides a rice cooker and rice cooking method that detects boiling more accurately and improves the taste of rice.

The rice cooker of the present disclosure includes a housing, a pot, a heating unit, a pressure detection unit, and a control unit. The pot is housed in the housing and contains food to be cooked, including rice and water. The heating unit is disposed within the housing and heats the pot. The pressure detection unit detects the pressure within the pot. The control unit controls the heating unit. The control unit controls the heating unit to execute a rice cooking process including a temperature increase process and a boiling maintenance process, and in the temperature increase process, the control unit controls the heating unit to heat the food to be cooked contained in the pot, and transitions to the boiling maintenance process when the pressure detection unit detects a first pressure higher than atmospheric pressure.

The rice cooking method disclosed herein is a method for cooking rice with a rice cooker that includes a housing, a pot that is housed in the housing and contains food to be cooked including rice and water, a heating unit that is disposed within the housing and heats the pot, a pressure detection unit that detects the pressure within the pot, and a control unit that controls the heating unit, and that performs a rice cooking process that includes a heating process and a boiling maintenance process. In the heating process, the food to be cooked contained in the pot is heated, and when the pressure detection unit detects a first pressure higher than atmospheric pressure, the process transitions to the boiling maintenance process.

The rice cooker and rice cooking method disclosed herein detect boiling by pressure detection. Therefore, it is possible to more accurately detect the boiling of water in the pot and transition to the boiling maintenance step at an appropriate time. As a result, the taste of the rice can be further improved.

Cross-sectional view of a rice cooker according to a first embodiment. FIG. 1 is an exploded perspective view of a rice cooker according to a first embodiment; FIG. 1 is a partially cutaway cross-sectional view of a rice cooker according to a first embodiment; FIG. 1A is a bottom perspective view showing the inner lid of the rice cooker according to the first embodiment as viewed from the pot side; FIG. 1B is a top perspective view showing the inner lid of the rice cooker according to the first embodiment as viewed from the lid body side; Timing chart showing all rice cooking steps in the first embodiment Timing chart showing a temperature increase process in the first embodiment

Below, the embodiments will be described in detail with reference to the drawings. However, more detailed explanations than necessary may be omitted. For example, detailed explanations of matters that are already well known, or duplicate explanations of substantially identical configurations may be omitted. This is to avoid making the following explanation unnecessarily redundant and to make it easier for those skilled in the art to understand.

The accompanying drawings and the following description are provided to enable those skilled in the art to fully understand the present disclosure, and are not intended to limit the subject matter described in the claims.

(Embodiment 1)
Hereinafter, the first embodiment will be described with reference to FIGS.

[1-1. Configuration]
Fig. 1 is a cross-sectional view of the rice cooker in the first embodiment. Fig. 2 is an exploded perspective view of the rice cooker in the first embodiment. Fig. 3 is a partially cut-away cross-sectional view of the rice cooker in the first embodiment.

The rice cooker of this embodiment has a main body 100 and a lid body 3.

The main body 100 has a housing 1, a pot 2, a lower heating section 4 (i.e., an example of a heating section of the present disclosure), a control section 6, a pot temperature detection section 1b, and a part of the steam injection means 36.

The housing 1 houses the pot 2, the lower heating unit 4, the control unit 6, etc. The shape of the housing 1 is a cylinder with a bottom. The housing 1 has a storage section 1a with a housing opening at the top.

The pot 2 is a container in which rice, water, and other items to be heated are stored. The shape of the pot 2 is a bottomed cylinder with a pot opening 2a at the top. The pot 2 is placed in the storage section 1a of the housing 1.

The lower heating unit 4 heats the pot 2. The lower heating unit 4 is arranged, for example, on the bottom and sides of the pot 2. In this embodiment, the lower heating unit 4 is a wound coil and is an induction heating type heating unit. The heating unit may be of a type other than induction heating, for example, a microcomputer heater, etc.

The control unit 6 controls the lower heating unit 4, the upper heating unit described below, the display unit 8, the operation unit 7, and the pressure adjustment valve 15b described below. The control unit 6 is disposed inside the housing 1 of the main body. The control unit 6 is composed of, for example, a CPU or a microcontroller. The control unit 6 has a memory unit. The memory unit stores a plurality of rice cooking sequences. Here, the rice cooking sequence refers to a rice cooking procedure in which the current application time, heating temperature, heating time, heating output, etc. are predetermined for each of the four main steps, namely, a preheating step, a temperature increase step, a boiling maintenance step, and a steaming step, are performed in order. Each rice cooking sequence corresponds to each of the plurality of rice cooking courses.

The pot temperature detector 1b detects the temperature of the bottom of the pot. The pot temperature detector 1b is disposed on the bottom surface of the storage section 1a of the housing 1. The pot temperature detector is, for example, a thermistor.

The steam introduction means 36 shown in FIG. 2 is a device for introducing water vapor or superheated steam into the pot 2. The steam introduction means 36 has a water container 31, a water container heating unit, a steam inlet pipe, a steam exhaust pipe, and a steam supply unit. The water container 31 is a container into which the user puts water. A water container opening is provided on the top surface of the housing 1. The water container 31 is disposed around the pot 2. The water container heating unit heats the water inside the water container 31. The water container heating unit is disposed on the side of the water container 31. The water container heating means is, for example, a wound coil. The steam introduction pipe is provided to guide the water vapor or superheated steam released from the water container 31 to the steam supply unit. The steam supply unit heats the steam introduced from the water container 31 through the steam introduction pipe to make it superheated steam, and supplies the superheated steam into the pot 2 through the steam exhaust pipe. A ring-shaped packing is attached to the end of the steam introduction pipe on the water container 31 side. The packing is arranged to fit tightly against the flange of the water container 31 when the lid is in the closed state. The steam exhaust pipe is connected to the inside of the pot 2 through a steam supply hole provided in the inner lid 10 (described later) when the lid is in the closed state, and is arranged to guide the steam generated in the steam supply unit into the pot 2. Note that the specific configuration of the steam supply unit is similar to that of a conventional steam supply unit, so a description thereof will be omitted here.

The lid body 3 has an outer lid 25 shown in FIG. 3, an inner lid 10 shown in FIG. 2, a lid temperature detection unit (not shown), a pressure detection unit 26 shown in FIG. 3, an upper heating unit, and a hinge unit 1c.

As shown in FIG. 1, the outer lid 25 has a steam cylinder 9, a display unit 8, and an operation unit 7. The outer lid 25 can seal the housing opening at the top of the housing 1. The steam cylinder 9 is a device for discharging steam from inside the pot 2 to the outside. The steam cylinder 9 is composed of a steam cylinder main body 9a having an opening (not shown) at the top, and a steam cylinder lid 9b that can open and close and cover the opening (not shown) of the steam cylinder main body 9a. The steam cylinder main body 9a is formed with a steam inlet 9c through which steam generated inside the pot 2 flows into the steam cylinder 9. The steam cylinder lid 9b is formed with a steam outlet 9d that discharges steam that flows into the steam cylinder 9 from the steam inlet 9c to the outside of the steam cylinder 9.

The display unit 8 is a screen that allows the user to select the cooking course, etc. The display unit 8 is located on the top surface of the outer lid 25. The display unit 8 is, for example, a liquid crystal touch panel. The display unit 8 also serves as part of the operation unit 7, and accepts instructions from the user, such as menu selection and reservation time setting.

The operation unit 7 accepts instructions from the user, such as an instruction to start cooking rice and to select a menu. The operation unit 7 is, for example, a mechanical switch or an electrostatic switch. The display unit 8 may function as part or all of the operation unit 7.

Figure 4(a) is a bottom perspective view showing the inner lid of the rice cooker in embodiment 1 as seen from the pot side, and Figure 4(b) is a top perspective view showing the inner lid of the rice cooker in embodiment 1 as seen from the lid body side. As shown in Figures 4(a) and 4(b), the inner lid 10 has a heating plate 11.

On the cover body 3 side of the heating plate 11, there are arranged a pressure regulating valve housing 15a housing a pressure regulating valve (15b shown in FIG. 1) that opens and closes the first steam exhaust port 11a, a pressure suppression valve housing 16a housing a pressure suppression valve 16b that opens and closes the second steam exhaust port 11b, a safety valve housing 17a housing a safety valve 17b that opens and closes the third steam exhaust port 11c, and a valve housing 14 having a sticky reflux valve attachment portion 18a to which a sticky reflux valve 18b that opens and closes the sticky reflux port 11d is attached.

The lid temperature detector is a device for detecting the temperature of steam inside the pot 2. The lid temperature detector is disposed on the heating plate 11 side of the inner lid 10. The lid temperature detector is, for example, a thermistor.

The pressure detection unit 26 shown in FIG. 1 detects the pressure inside the pot 2. The pressure detection unit 26 is disposed in a storage section provided in the outer lid 25. The pressure detection unit 26 is disposed between the outer lid 25 and the inner lid 10. For example, the pressure detection unit 26 is a pressure sensor disposed inside the pot 2 in the inner lid 10, which detects the pressure inside the pot 2 and transmits it to the control unit 6.

The hinge portion 1c shown in FIG. 1 is a mechanical part that supports the lid body 3 and opens and closes it. The hinge portion 1c connects the lid body 3 and the housing 1, and is located on the back surface of the housing 1.

[1-2. motion]
The rice cooking process of this embodiment will be described.

Figure 5 is a timing chart showing the entire rice cooking process in embodiment 1. As shown in Figure 5, the rice cooking process includes a preheating process, a temperature increase process, a boiling maintenance process, and a steaming process.

The preheating process is a process in which rice is soaked in water that is lower than the gelatinization temperature, and the rice absorbs the water. The preheating process is started, for example, when the user inputs an instruction to start cooking rice via the operation unit 7. The control unit 6 controls the heating unit to raise the temperature in the pot 2 in the preheating process until it reaches a predetermined temperature θ1, and then maintains the temperature θ1 for a predetermined time T0. At this time, in this embodiment, the pressure adjustment valve 15b shown in FIG. 1 remains closed. The control unit 6 maintains the temperature in the pot 2 at a constant temperature θ1 for the predetermined time T0, and then ends the preheating process and moves to the heating process.

Figure 6 is a timing chart showing the heating process in embodiment 1. The heating process is a process in which the pot 2 is heated and the water in the pot 2 reaches the boiling point. As shown in Figure 6, the heating process has a high heat process and a low heat process at the end of the heating process. When the heating process starts, the control unit 6 opens the pressure adjustment valve 15b and controls the upper heating unit and the lower heating unit 4 to heat the inside of the pot 2 until the lid temperature detection unit detects the first temperature θ2. When the lid temperature detection unit detects the first temperature θ2, the control unit 6 transitions to the high heat process.

During the high heat step, the control unit 6 controls the upper heating unit and the lower heating unit 4 to heat the inside of the pot 2 while closing the pressure adjustment valve 15b along the way so that the first pressure P1 is reached in the first predetermined time T1 after the start of the high heat step. Also, when boiling occurs, a sufficient amount of steam is generated, the sticky reflux valve 18b closes, and the internal pressure rises. In this way, the control unit 6 ends the high heat step and transitions to the low heat step when the pressure detection unit 26 detects the first pressure P1.

In the low heat step, the control unit 6 controls the upper heating unit and the lower heating unit 4 to heat the inside of the pot 2 at a lower heat than the high heat step for a predetermined time T2 after the start of the low heat step. Here, the low heat step is a step in which the amount of current (amount of current flowing through the coil) per unit time is smaller than that in the high heat step. In the low heat step, the control unit 6 closes the pressure adjustment valve 15b for the first predetermined time T3, but opens the pressure adjustment valve 15b midway. In this embodiment, while the pressure adjustment valve 15b is closed in the low heat step, the pressure in the pot 2 rises to a predetermined pressure P2. After that, when the pressure adjustment valve 15b opens, the pressure in the pot 2 drops toward atmospheric pressure. At this time, the rice and water convect in the pot 2. When the predetermined time T2 has elapsed, the control unit 6 transitions from the low heat step to the boiling maintenance step. In this embodiment, if the first pressure P1 is not reached even after heating for a second predetermined time after the start of the high heat step, the control unit 6 ends the high heat step and transitions to the low heat step.

The boiling maintenance process is a process in which boiling is maintained until the water in the pot 2 is depleted, promoting the gelatinization of the rice. In the boiling maintenance process, the control unit 6 repeatedly opens and closes the pressure adjustment valve 15b several times, changing the pressure in the pot 2 multiple times. Furthermore, the control unit 6 repeatedly controls the on and off of the lower heating unit 4 and the upper heating unit to maintain boiling. When the water in the pot 2 evaporates and the temperature in the pot 2 rises, and the pot temperature detection unit 1b detects a predetermined temperature θ3, the control unit 6 ends the boiling maintenance process and transitions to the steaming process.

The steaming process is a process for further increasing the degree of gelatinization of the rice and homogenizing the moisture content of the rice. During the steaming process, the control unit 6 controls the pressure adjustment valve 15b to close the first steam outlet 11a, and controls the steam introduction means 36 to supply superheated steam into the pot 2, thereby increasing the pressure inside the pot 2. When the specified time has elapsed, the control unit 6 ends the steaming process and sounds a buzzer.

[1-3. Effects]
The rice cooker according to the present embodiment has the following advantages.

According to the pressure rice cooker of this embodiment, the control unit 6 controls the heating unit (for example, the upper heating unit and the lower heating unit 4) to perform the rice cooking process including the temperature increase process and the boiling maintenance process. Furthermore, in the temperature increase process, the control unit 6 controls the heating unit (for example, the upper heating unit and the lower heating unit 4) to heat the food contained in the pot 2, and transitions from the temperature increase process to the boiling maintenance process when the pressure detection unit 26 detects a first pressure P1 higher than atmospheric pressure. In this way, the pressure detection unit 26 detects boiling, so that it can detect boiling more accurately and transition to the boiling maintenance process at an appropriate time. This can further improve the taste of the rice. Note that the control unit 6 does not need to heat the upper heating unit in the temperature increase process.

In the rice cooker according to this embodiment, the heating process includes a high heat process and a low heat process with less heat than the high heat process, and the control unit 6 transitions from the high heat process to the boiling maintenance process via the low heat process when the pressure detection unit 26 detects the first pressure P1 during the high heat process. This further reduces the possibility of transitioning from the heating process to the boiling maintenance process before boiling, or transitioning to the boiling maintenance process in an over-boiling state. This prevents rice grains from crumbling, reducing the possibility of a deterioration in taste.

In the rice cooker according to this embodiment, the control unit 6 starts the high heat process when the steam temperature reaches the first temperature θ2 during the heating process, and controls the lower heating unit 4 and the upper heating unit so that the time from the start of the high heat process until the first pressure P1 is reached is the first predetermined time T1. By controlling the heat in this way, the food being cooked in the pot can be given the desired pressure and time. This prevents the rice grains from crumbling, ensuring the desired taste.

In the rice cooker according to this embodiment, the control unit 6 ends the high heat process if the first pressure P1 is not reached even after heating for a second predetermined time after the start of the high heat process. By setting the time limiter in this way, overflow is prevented and rice can be cooked without crumbling. This reduces the possibility of the taste deteriorating.

The rice cooking method of this embodiment is a rice cooking method of a rice cooker including a housing 1, a pot 2 that is housed in the housing 1 and contains food to be cooked including rice and water, a heating unit that is arranged in the housing 1 and heats the pot 2, a pressure detection unit 26 that detects the pressure in the pot 2, and a control unit 6 that controls the heating unit. The rice cooker executes a rice cooking process that includes a temperature increase process and a boiling maintenance process. In the temperature increase process, the rice cooker heats the food to be cooked contained in the pot 2, and when the pressure detection unit 26 detects a first pressure P1 higher than atmospheric pressure, the rice cooker transitions to the boiling maintenance process. In this embodiment, the pressure detection unit 26 detects boiling, so that boiling can be detected more accurately and the process can be transitioned to the boiling maintenance process at an appropriate time. This can further improve the taste of the rice.

In the rice cooking method of this embodiment, the heating process includes a high heat process and a low heat process with less heat than the high heat process. In this rice cooking method, when the pressure detection unit 26 detects the first pressure P1 in the high heat process, the process transitions from the high heat process to the low heat process and then to the boiling maintenance process. This further reduces the possibility of transitioning from the heating process to the boiling maintenance process before boiling, or transitioning to the boiling maintenance process in an over-boiling state. This prevents rice grains from crumbling, reducing the possibility of a deterioration in taste.

In the rice cooking method of this embodiment, when the steam temperature reaches a first temperature during the heating process, the high heat process is started, and the lower heating unit 4 and the upper heating unit are controlled so that the time from the start of the pre-heat process until the first pressure P1 is reached is the first predetermined time θ2. By controlling the heat in this way, the rice being cooked in the pot can be given the desired pressure and time. This prevents the rice grains from crumbling, and ensures the desired taste.

In the rice cooking method of this embodiment, if the first pressure P1 is not reached even after the second predetermined time has passed since the start of the high heat process, the high heat process is terminated. By setting the time limiter in this manner, overflow is prevented and the rice can be cooked without crumbling. This reduces the possibility of the rice's flavor being deteriorated.

[1-4. Other embodiments]
As described above, the first embodiment has been described as an example of the technology disclosed in the present application. However, the technology in the present disclosure is not limited to this, and can be applied to embodiments in which modifications, substitutions, additions, omissions, etc. are made. In addition, it is also possible to combine the components described in the first embodiment to create a new embodiment.

Therefore, other embodiments are given below as examples.

In the above-described embodiment, the rice cooker body is configured to have two heating coils, a bottom heating coil and a side heating coil, but the number of heating coils may be one or three or more. The heating coil may be located on either the bottom side or the side of the pot 2.

The heating section may be an induction heating type heating section that is heated by applying a high-frequency current as described above, or may be a heater such as an electric heater.

In the above, one pressure regulating valve 15b is provided in one pressure regulating valve housing 15a, but the present disclosure is not limited to this. For example, multiple pressure regulating valves 15b may be provided in one pressure regulating valve housing 15a.

In the above, the pressure detection unit 26 is used to detect the pressure in the space inside the pot 2 of a pressure rice cooker, but the present disclosure is not limited to this. The pressure detection unit 26 can be used to detect the pressure in a steam generation space where steam is generated, such as the space inside the pot 2 of a pressure cooker.

In addition, the values, shapes, and materials used in the above-mentioned embodiments are all examples used to specifically explain this disclosure, and this disclosure is not limited to the values, shapes, and materials exemplified.

The present disclosure also includes forms obtained by applying various modifications to the above-described embodiments that may occur to those skilled in the art, as well as forms realized by arbitrarily combining the components and functions of the embodiments without departing from the spirit of this disclosure.

This disclosure can further improve the taste of cooked rice, and is therefore useful, for example, in home and commercial rice cookers.

LIST OF SYMBOLS 1 Housing 1a Storage section 1b Pot temperature detection section 1c Hinge section 2 Pot 2a Pot opening 3 Lid 4 Lower heating section 6 Control section 7 Operation section 8 Display section 9 Steam cylinder 9a Steam cylinder main body section 9b Steam cylinder lid section 9c Steam inlet 9d Steam outlet 10 Inner lid 11 Heating plate 11a First steam outlet 11b Second steam outlet 11c Third steam outlet 11d Sticky liquid reflux port 14 Valve accommodating section 15a Pressure regulating valve accommodating section 15b Pressure regulating valve 16a Pressure suppression valve accommodating section 16b Pressure suppression valve 17a Safety valve accommodating section 17b Safety valve 18a Sticky liquid reflux valve mounting section 18b Sticky liquid reflux valve 25 Outer lid 26 Pressure detection section 31 Water container 36 Steam supply means 100 Main body

Claims (6)

A housing and
A pot that is housed in the housing and contains food to be cooked, including rice and water;
A heating unit disposed within the housing for heating the pan;
A pressure regulating valve for regulating the pressure in the pot;
A pressure detection unit that detects the pressure inside the pot;
A control unit that controls the heating unit,
The control unit controls the heating unit to perform a rice cooking process including a temperature increasing process and a boiling maintaining process,
The temperature increasing process includes a high heat process and a low heat process having a lower heat than the high heat process,
The control unit is configured to transition from the high heat step to the low heat step and then to the boiling maintenance step when the pressure detection unit detects a first pressure higher than atmospheric pressure in the high heat step,
In the low heat step, the pressure regulating valve is opened to reduce the pressure in the pot, thereby generating convection in the pot. The control unit is
2. The rice cooker according to claim 1, wherein the high heat process is started when the steam temperature reaches a first temperature in the temperature increasing process, and the heating unit is controlled so that a time from the start of the high heat process to the reaching of the first pressure is a first predetermined time. The rice cooker according to claim 1 or 2, wherein the control unit terminates the high heat step if the first pressure is not reached even after heating for a second predetermined time after the start of the high heat step. A housing and
A pot that is housed in the housing and contains food to be cooked, including rice and water;
A heating unit disposed within the housing for heating the pan;
A pressure regulating valve for regulating the pressure in the pot;
A pressure detection unit that detects the pressure inside the pot;
A rice cooking method for a rice cooker comprising:
A rice cooking process including a temperature increasing process and a boiling maintaining process is performed,
The temperature increasing process includes a high heat process and a low heat process having a lower heat than the high heat process,
When the pressure detection unit detects a first pressure higher than atmospheric pressure in the high heat step, the process transitions from the high heat step through the low heat step to the boiling maintenance step,
In the low heat step, the pressure regulating valve is opened to reduce the pressure in the pot, thereby generating convection in the pot. The rice cooking method according to claim 4, wherein the high heat process is started when the steam temperature reaches a first temperature during the temperature increase process, and the heating unit is controlled so that the time from the start of the high heat process to the time when the first pressure is reached is a first predetermined time. The rice cooking method according to claim 4 or 5, wherein the high heat step is terminated if the first pressure is not reached even after heating for a second predetermined time after the start of the high heat step.