JP2013184005A - Pan for cooking rice - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a pan for cooking rice capable of bringing the properties of cooked rice into a desired stable state even when controlling rice cooking on the basis of the temperature detection value of a temperature sensor abutted on the bottom of the pan.SOLUTION: A pan 4 for cooking rice has a temperature sensor 2 abutted on the bottom surface of the pan 4, the sensor measuring a pan bottom temperature as a temperature of the bottom surface of the pan 4, and is heated by a combustion flame formed by a gas burner 3. A sensor abutting part 11, or an abutting position of the temperature sensor 2, is provided with a boiling control means 13 for controlling local boiling at the sensor abutting part 11.

Description

  The present invention relates to a rice cooking pan that is heated by a combustion flame formed in a gas burner, in which a temperature sensor that measures a pan bottom temperature that is a temperature of the bottom surface of the pan is brought into contact with the bottom surface.

Rice cooking pots that cook rice by heating from below with a heat source such as a burner or a heater include a rice cooking pot made for the purpose of cooking using a gas appliance (such as a stove) equipped with a gas burner. As a rice cooker used in combination with a gas appliance, one used as an inner pot of a gas rice cooker as shown in Patent Document 1 or one placed on a gas stove as shown in Patent Document 2 is known. Yes. When cooking rice by automatic control using these cooking pots, as shown in Patent Document 3, a temperature sensor capable of measuring the temperature at the bottom of the pot is provided, and the heating timing and heating time by the gas burner are set to the temperature sensor. There is known a method of performing based on the output of.
In this type of rice cooking pan, basically, the same material is used to form the pan, and a special structure has not been adopted particularly on the bottom surface where the temperature sensor contacts.

JP 2007-37826 A JP 2006-192102 A JP 2010-068854 A

  Generally, in rice cooking using this kind of rice cooking pan, the temperature sensor detects the boiling state in the pan and uses the point at which the boiling state is stably continued to control rice cooking time (especially boiling time) Is adopted. When cooking is performed using a conventional rice cooking pot on a stove equipped with a control device that performs such rice cooking control, the rice cooking result (cooking condition of rice) may vary. found. That is, it has been found that the problem that the boiling time is too long or too short occurs.

  The present invention has been made in view of the above-mentioned problems, and the purpose thereof is to obtain the desired property of cooked rice even when performing rice cooking control based on the temperature detection value of the temperature sensor in contact with the bottom of the pan. The object is to obtain a cooking rice pan that can be made stable.

  A feature of the rice cooking pan according to the present invention is a rice cooking pan heated by a combustion flame formed in a gas burner, with a temperature sensor that measures the bottom temperature of the bottom of the pan being brought into contact with the bottom. The sensor abutting portion corresponding to the abutting position of the temperature sensor is provided with boiling suppression means for suppressing local boiling at the sensor abutting portion.

  The inventors diligently studied the cause of the variation in the properties of the above-mentioned cooked rice in completing the present invention. As a result, when local temperature rise and boiling occur in the vicinity of the contact point of the temperature sensor in the pan, the output of the temperature sensor is disturbed as shown by the frame in FIG. With this disturbance, it has been found that variations occur at the time point when the control side detects that the boiling state is stably continued. When local boiling occurs in this way, the output of the temperature sensor is disturbed, which affects the determination of heating timing and boiling time, and is one of the factors that determine the flavor that is the property of rice at the end of cooking. It was supposed to change the moisture content.

  Therefore, in the rice cooking pan according to the present application, the sensor contact portion corresponding to the contact position of the temperature sensor is provided with boiling suppression means for suppressing local boiling at the sensor contact portion. As a result, since the local boiling of the water in the pan in the sensor contact portion is suppressed by the action of the boiling suppression means during rice cooking, the pan bottom temperature in the sensor contact portion can be stably measured by the temperature sensor. For this reason, it is possible to determine heating time such as heating timing and boiling time of thermal power control determined based on the output of the temperature sensor with high accuracy.

  Here, the gas device absorbs a predetermined amount of water into the cooked rice in the pan, the temperature increasing step for raising the temperature of the water in the pan until it boils, and the boiling maintaining step for maintaining the boiling of the water in the pan The control means controls the heating time of the gas burner in the boiling maintenance step and the temperature in the boiling maintenance step. It is good to control based on the output of a sensor, and it is good for the boiling suppression means to suppress local boiling in the sensor contact part in the boiling maintenance process.

  According to such a configuration, since the output of the temperature sensor in the boiling maintenance process can be stabilized, the heating time of the gas burner controlled based on the output of the temperature sensor is determined with high accuracy in the boiling maintenance process. be able to.

  Furthermore, as the boiling suppression means, the material of the sensor contact portion may be made of a metal having lower thermal conductivity than the material other than the sensor contact portion.

  According to such a configuration, the heat conduction at the sensor contact portion is deteriorated, so that the heat flux on the inner surface of the sensor contact portion is smaller than the portion other than the sensor contact portion, and the local area at the sensor contact portion is reduced. Boiling can be suppressed.

  Alternatively, as the boiling suppression means, a configuration in which a smooth heat equalizing plate is attached to the inner surface of the sensor abutting portion may be used.

  According to such a configuration, at least the heat flux on the surface of the soaking plate can be made constant, and local boiling at the sensor contact portion can be suppressed.

  Alternatively, the boiling suppression means may be configured to be finished so that the surface roughness of the inner surface of the sensor contact portion is smaller than that other than the sensor contact portion.

  According to such a configuration, the formation site of boiling nuclei can be reduced by reducing the surface roughness. Furthermore, in the region where the surface roughness of the sensor contact portion is small, the heat flux is kept relatively constant as compared to other regions, so that local boiling at the sensor contact portion can be suppressed.

  The rice cooking pan that has been described so far can be suitably used in applications where the temperature sensor and the gas burner are provided in a gas stove and are heated by a combustion flame formed by the gas burner provided in the gas stove. it can.

  Moreover, the rice cooker which has a structure peculiar to this application is provided, a temperature cooker and a gas burner are provided in a rice cooker main body, and a gas rice cooker is comprised, The stable rice cooking can be performed with the said gas rice cooker.

The schematic diagram of the state which is cooking on the stove using the cooking pot concerning 1st Embodiment of this invention The figure which shows the relationship between the thermal-power control of the gas burner which concerns on this invention, and the output of a temperature sensor Control flow diagram of gas burner according to the present invention Schematic diagram of a rice cooking pan according to a second embodiment of the present invention. Schematic diagram of a rice cooking pan according to a third embodiment of the present invention. The figure which shows the experimental result of this invention, and the experimental result by a prior art example

1. Configuration of Gas Appliance Including Rice Cooking Pot Hereinafter, the rice cooking pot 4 according to the present invention will be described with reference to FIGS. As shown to Fig.1 (a), the gas stove 1 which is a gas apparatus is equipped with the virtues 6 for mounting a to-be-mounted object on the gas stove 1, and is the temperature of the bottom face of the pan mounted in the virtues 6. It has a temperature sensor 2 and a gas burner 3 for measuring the pan bottom temperature. The gas burner 3 is configured to heat the bottom surface of the rice cooking pan 4 with the combustion flame formed. In the present embodiment, the gas burner 3 is configured to have a plurality of flame holes on the circumference when viewed from the vertical direction. The temperature sensor 2 is a contact-type temperature sensor and is configured to protrude upward in the vertical direction at the center of the gas burner 3.

  The cooking rice pan 4 is placed on the gas stove 1 through the five virtues 6. The rice cooking pan 4 is made of stainless steel or aluminum, and the inner surface is processed with fluororesin. In this embodiment, it is mainly composed of aluminum. With this configuration, in the present embodiment, the temperature sensor 2 can detect the pan bottom temperature at the center of the bottom surface of the rice cooking pan 4 that is an object to be mounted.

  The rice cooking pan 4 is characterized in that the sensor contact portion 11 corresponding to the contact position of the temperature sensor 2 is provided with a boiling suppression means 13 that suppresses local boiling at the sensor contact portion 11. Here, in this specification, the sensor contact portion 11 means a part (region) of the rice cooking pan 4 including a surface where the rice cooking pan 4 and the temperature sensor 2 come into contact when viewed in the vertical direction.

2. Prior to explaining the characteristic configuration of the rice cooking pan 4, the following description will be made using the thermal power control of the gas stove 1 during rice cooking. As shown in FIG. 1, the gas stove 1 includes control means 5 for cooking rice using a cooking rice pan 4. As shown in FIG. 2, the control means 5 controls the heating power and heating time of the gas burner 3, so that the so-called water absorption process A, temperature rising process B, boiling maintaining process at the time of rice cooking as time passes from the start of rice cooking. It is comprised so that C may be performed in order.

  Here, the water absorption process A is a process in which a predetermined amount of water is absorbed by the rice that is the cooked rice in the rice cooking pot 4, and the temperature rising process B is heated until the water in the rice cooking pot 4 is boiled. A process, the boiling maintenance process C means the process of maintaining the boiling of the water in a pan.

  Furthermore, in this embodiment, the water absorption process A includes a first water absorption process A1 for heating the rice cooking pot 4 with high heat in order to estimate the amount of rice Wr in the rice cooking pot 4 from the temperature change amount, and water absorption of rice. In order to promote this, it consists of the 2nd water absorption process A2 which heats the rice cooking pot 4 with low heat compared with 1st water absorption process A1 so that the water temperature in the rice cooking pot 4 may be kept at appropriate temperature. Here, the heating time Δt1 of the second water absorption step A2 is determined based on the rice amount Wr estimated in the first water absorption step A1.

  Moreover, the boiling maintenance process C is a low heat compared with the 1st boiling maintenance process C1 and the 1st boiling maintenance process C1 which heat the cooking pot 4 with a strong fire in the stage where it was estimated that the water in the cooking pot 4 boiled. It consists of the 2nd boiling maintenance process C2 which heats the pan 4 for rice cooking.

  Here, the control means 5 is configured to control the heating time Δtc of the gas burner 3 in the boiling maintenance process C based on the output T of the temperature sensor in the boiling maintenance process C. In the present embodiment, the heating time Δtc of the gas burner 3 in the boiling maintenance step C is the sum of the heating time Δtc1 in the first boiling maintenance step C1 and the heating time Δtc2 in the second boiling maintenance step C2. Here, the heating time Δtc1 for determining the heating time Δtc is determined based on the equilibrium detection timing td at which it is determined that the output T of the temperature sensor 2 in the first boiling maintenance step C1 in the rice cooking pot 4 has become constant. The More specifically, in the first boiling maintenance step C1, the gas burner 3 is heated for the heating time Δt2 based on the estimated rice amount Wr from the equilibrium detection timing td.

  Next, an example of the heating power control flow of the gas burner 3 by the control means 5 will be described based on FIG. When the rice cooking pot 4 in which rice and water are put is placed on the gas stove 1 and rice cooking is started by a switch or the like provided on the gas stove 1, the control means 5 first sets the heating power of the gas burner 3 to be strong ( Step # 1). Next, it waits until 60 seconds have passed from the start (step # 2: No), and when 60 seconds have passed (step # 2: Yes), the temperature gradient a = dT / dt for 60 seconds is calculated (step). # 3). And based on the temperature gradient a, the rice amount Wr in the rice cooking pot 4 is estimated using a heat balance equation, and the heating time Δt1 and the first boiling maintenance step in the second water absorption step A2 from the estimated rice amount Wr. The heating time Δt2 in C1 is determined based on a database stored in advance. The control so far corresponds to the first water absorption step A1 in FIG.

The method for estimating rice quantity using the heat balance equation is described below. The thermal power of the gas burner 3 is Q _in [W], the thermal efficiency of the gas burner 3 when using the rice cooking pan 4 is η,
C _p W _p ΔT _p + C _w W _w ΔT _w + C _r W _r ΔT _r = Q _in η (1)
κ = W _w / W _r (= water weight “g” / rice weight “g”) (2)
here,
C _p , W _p , ΔT _p : specific heat [J / g ° C.], weight [g], heating rate [° C./s] of the rice cooking pan 4
C _w , W _w , ΔT _w : specific heat of water [J / g ° C.], weight [g], rate of temperature increase [° C./s]
C _r , W _r , ΔT _r : specific heat of rice [J / g ° C.], weight [g], heating rate [° C./s]
From equation (1) and equation (2), the amount of rice Wr is
_{Wr = (Q in η-C} p W p ΔT p) / (C w κΔT w + C r ΔT r) ... (3)
It becomes.
Furthermore, if it is considered that the rice and water are completely mixed, ΔT _w = ΔT _r , the temperature of the inner surface of the cooking pot 4 is the same temperature T _w as the water, and the temperature of the outer surface is the same as the output T of the temperature sensor 2 Considering ΔT _p = (1/2) ΔTw (1 + 1 / a) (a is a known coefficient indicating the relationship between the pot bottom temperature T and the water temperature in the rice cooking pot 4), the amount of rice from the equation (3) Wr can be estimated.

  Subsequently, the control means 5 sets the heating power of the gas burner 3 to be weak (step # 11). It waits until heating time (DELTA) t1 second passes (step # 12: No). The control so far corresponds to the second water absorption step A2 in FIG.

Further, when the heating time Δt1 second has elapsed (step # 12: Yes), the heating power of the gas burner 3 is increased (step # 21). The output T of the temperature sensor 2 is stored as the immediately preceding temperature T ₀ (step # 22). Next, the difference between the current output T of the temperature sensor 2 and the immediately preceding temperature T ₀ is obtained, and it is checked whether the absolute value is 1 or less (step # 23). When the difference is larger than 1, the process starts again from step # 22 (step # 23: No). When the difference is 1 or less (step # 23: Yes), the time is set as the equilibrium detection timing td. Then, it waits for heating time (DELTA) t2 (step # 25: No). When the heating time Δt2 has elapsed, the output T of the temperature sensor 2 immediately after the end of the heating time Δt2 is stored as an end determination temperature T1 (step # 26). The control so far corresponds to the temperature raising step B and the first boiling maintenance step C1 in FIG.

Subsequently, the control means 5 sets the heating power of the gas burner 3 to be weak (step # 31). The process waits while the output T of the temperature sensor 2 is smaller than the end determination temperature T1 + 30 ° C. (step # 32). When the output T becomes equal to the end determination temperature T1 + 30 ° C., the gas burner 3 is extinguished (step # 41). The steps so far correspond to the second boiling maintenance step C2 in FIG. Above, the thermal power control by the control means 5 is complete | finished.
Therefore, in this rice cooking control, the property of the rice from which the “equilibrium detection timing td” referred to in the present application is greatly affected.

3. Specific Configuration Example of Boiling Suppression Unit When cooking rice with the heating power control shown in FIG. 2, when using the rice cooking pan 4 of the present invention, the boiling suppression unit 13 causes the boiling maintenance step C (first boiling maintenance step C1). ), The local boiling at the sensor contact portion 11 is suppressed, so that the output T of the temperature sensor 2 can be prevented from fluctuating due to the local boiling. For this reason, the time lag from the start of the boiling maintenance process C to the equilibrium detection timing td is shortened, and the heating time Δtc of the boiling maintenance process C until the extinction can be set with higher accuracy. Below, the Example of the boiling suppression means 13 is described.

[First embodiment]
As shown in FIG. 1B, as an example of the boiling suppression means 13, the material of the sensor contact portion 11 can be composed of a metal 13 a having lower thermal conductivity than the material other than the sensor contact portion 11. . In the example of FIG.1 (b), the material of the rice cooking pan 4 is made into aluminum, and the material of the sensor contact part 11 is made into stainless steel. In the example of FIG. 1B, the entire sensor contact portion 11 is made of a different material, but only a part of the sensor contact portion 11 may be made of the metal 13a having poor thermal conductivity. Specifically, the pan bottom of the rice cooking pan 4 may have a multilayer structure, the outermost layer may be integrally formed, and the inner layer may be made of different materials for the sensor abutting portion 11 and the others. .

  Here, the magnitude | size of the heat flux in each location of the inner surface of the rice cooking pot 4 is shown by the arrow in FIG.1 (b). By setting it as such a structure, as shown in a figure, the heat flux in the inner surface vicinity of the sensor contact part 11 becomes smaller than the heat flux other than the sensor contact part 11. FIG. For this reason, the temperature rise of the sensor contact portion 11 becomes moderate, and the possibility of local boiling can be reduced.

[Second Embodiment]
As shown in FIG. 4, the boiling suppression means 13 may have a configuration in which a smooth soaking plate 13 b is attached to the inner surface of the sensor contact portion 11. In the example of FIG. 4, the soaking plate 13 b is sized to cover the periphery of the sensor contact portion 11 when viewed in the vertical direction, and aluminum is used as the material. With such a configuration, as indicated by arrows in FIG. 4, the heat flux near the surface of the soaking plate 13b can be made uniform, and the possibility of local boiling at least in the sensor contact portion 11 can be reduced. .

[Third embodiment]
As shown in FIG. 5, as the boiling suppression means 13, a high-precision region finished on the inner surface of the bottom of the pan corresponding to the sensor contact portion 11 of the rice cooking pan 4 so that the surface roughness is smaller than that other than the sensor contact portion 11. It is good also as a structure provided with 13c. With such a configuration, it is possible to reduce the possibility of variation in the heat flux in the vicinity of the surface of the sensor contact portion 11 as compared to other than the sensor contact portion 11, and at the same time, a location that becomes the core of local boiling Can be reduced.

4). Experimental Results Finally, FIG. 6 shows the result of a comparative experiment between the case where the conventional boiling suppression means 13 is not provided and the case where the boiling suppression means 13 according to the present invention is provided. The vertical axis of each graph in FIG. 6 indicates the output (temperature (° C.)) T of the temperature sensor 2, and the horizontal axis indicates the time since the heating of the rice cooking pan 4 is started. Moreover, the arrows at the bottom of the graph indicate the water absorption process A, the temperature raising process B, the boiling maintenance process C, and the unevenness process D, respectively. 6 (a) shows the temperature change when using the conventional rice cooking pan 4 without the boiling suppression means 13, and FIG. 6 (b) shows the rice cooking with the boiling suppression means 13 according to the present invention. The state of the temperature change when the pan 4 is used is shown.

  In the conventional rice cooking pan 4, as shown in FIG. 6A, immediately after the start of the boiling maintenance step C, a rapid temperature change that seems to be due to local boiling at the sensor contact portion 11 was observed. For this reason, a period from the start of the boiling maintenance process C to the equilibrium detection timing td is vacant.

  On the other hand, in the rice cooking pot 4 according to the present invention, as shown in FIG. 6 (b), immediately after the start of the boiling maintenance process C, the temperature does not change abruptly, and is balanced with the start of the boiling maintenance process C. The time lag with respect to the detection timing td could be reduced. As a result, rice having a moisture content of 63 to 63.5%, which is the moisture content of rice having ideal hardness, can be stably cooked.

  Thus, in the rice cooking pan 4 according to the present invention, the time lag between the boiling maintenance process C start and the equilibrium detection timing td generated by the local boiling at the sensor contact portion 11 can be reduced, and thus, The heating time in the boiling maintenance process C can be controlled with higher accuracy.

[Other Embodiments]
(1) In the said embodiment, an example in case the pan for rice cooking which concerns on this invention was used with a gas stove was shown. However, the present invention is not limited to the above embodiment. That is, you may use the cooking pot concerning this invention for a gas rice cooker.

(2) In the said embodiment, the control shown in FIG. 2 was shown as an example which the control means 5 which concerns on this invention controls the thermal power of the gas burner 3. As shown in FIG. However, the present invention is not limited to the above embodiment. That is, for example, the control means 5 may perform thermal power control (so-called quick cooking mode) so as to omit the water absorption process.

  INDUSTRIAL APPLICABILITY The present invention can be applied to a rice cooking pan that is heated by a combustion flame formed in a gas burner with a temperature sensor that measures the temperature at the bottom of the pan, which is a temperature at the bottom of the pan.

1: Gas stove 2: Temperature sensor 3: Gas burner 4: Cooking rice pot 5: Control means 11: Sensor contact part 13: Boiling suppression means 13a: Metal 13b with poor thermal conductivity: Heat equalizing plate 13c: High precision region ( Area with small surface roughness)
A: Water absorption step B: Temperature rising step C: Boiling maintenance step Δtc: Heating time

Claims (7)

A temperature sensor for measuring the temperature at the bottom of the pot, which is a temperature at the bottom of the pot, is in contact with the bottom surface and is a cooking pot heated by a combustion flame formed in a gas burner,
A rice cooking pot provided with a boiling suppression means for suppressing local boiling at the sensor contact portion at a sensor contact portion corresponding to the contact position of the temperature sensor. Gas equipment performs a water absorption process in which a predetermined amount of water is absorbed by the cooked rice in the pan, a temperature rising process in which the water in the pan is boiled, and a boiling maintenance process in which the boiling of the water in the pan is maintained. And a control means for controlling the heating power and heating time of the gas burner in each step,
The control means is configured to control the heating time of the gas burner in the boiling maintenance step based on the output of the temperature sensor in the boiling maintenance step,
The rice cooking pot according to claim 1, wherein the boiling suppression means suppresses local boiling at the sensor contact portion in the boiling maintenance step.   The rice cooking pan according to claim 1 or 2, wherein the material for the sensor contact portion is made of a metal having lower thermal conductivity than the material other than the sensor contact portion as the boiling suppression means.   The rice cooking pot according to claim 1 or 2, wherein a smooth soaking plate is attached to the inner surface of the sensor contact portion as the boiling suppression means.   The rice cooking pot according to claim 1 or 2, wherein the boiling suppression means is finished so that the surface roughness of the inner surface of the sensor contact portion is smaller than that other than the sensor contact portion.   The cooking pot according to any one of claims 1 to 5, wherein the temperature sensor and the gas burner are provided in a gas stove, and are heated by a combustion flame formed by the gas burner provided in the gas stove.   A gas rice cooker comprising the rice cooking pot according to any one of claims 1 to 5, wherein the rice cooker body includes the temperature sensor and the gas burner.

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