JP2003009756A - Food heating apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a food heating apparatus enabling uniform heating treatment. SOLUTION: In this food heating apparatus having a steel belt conveyor served also as a heating surface and induction heating coils set under or above it, it is characteristic that each of the coils is ellipsoidal or rectangular and set so that the longitudinal direction of the coil make an angle of 45-135 deg. with the traveling direction of the steel belt.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a food heating device that uses a steel belt heated by an induction heating coil as a heating element and that enables uniform heat treatment.

[0002]

Steel belts are often used in the continuous heat treatment of food products. A gas-heated steel belt oven is often used for baked sweets such as cookies and cream puffs. However, there are problems such as poor energy efficiency, deterioration of working environment in terms of temperature, and safety concerns when using fire.

Japanese Unexamined Patent Publication No. 9-215605 discloses an invention relating to a heating processing apparatus using a steel belt by induction heating, which solves the above problems when using gas heating to some extent, and further provides an induction heating coil. Uniform heating is achieved by rocking. As a method of swinging the coil, a mechanical slide driving means using an air cylinder or a cam, or other generally known swinging means is used.

[0004]

However, in order to make uniform, it is necessary to set the fluctuation calculated from the heating distribution at rest, and even if the setting is calculated, the air cylinder, the cam, etc. It is difficult to set uniform rocking with the simple reciprocating rocking, and as a result, there has been a problem that uniformization cannot be realized unless an expensive system is combined with, for example, a thermograph, a computer, a servomotor.

[0005]

Means for Solving the Problems As a result of intensive studies to solve the above problems, the present inventors have found that a steel belt conveyor is used as a heating surface that also serves as a conveyor, and an induction heating coil is provided at the lower or upper portion of the steel belt. In the installed food heating device, the induction heating coil is oval or rectangular and is installed so that the angle formed by the longitudinal direction of the coil and the flow direction of the steel belt is 45 degrees or more and 135 degrees or less. It was found that the heating in the width direction can be made uniform. Further, by setting the distance of the induction heating coil in the width direction of the steel belt to be longer than the width of the steel belt, only the magnetic field from the linear portion of the coil acts on the steel belt, and the homogenization is easily realized. This has led to the completion of the present invention.

Next, the devices constituting the present invention will be described sequentially. In general, a steel belt conveyor is a type in which a steel strip is processed into a ring shape and both ends are driven by pulleys. The thickness of the steel material used as a steel belt must be determined from the strength and driveability of the belt, but it is generally 0.8 mm to 1.5 m.
It is better to use a steel strip of m. The material of the steel belt is
It is not limited to the expression steel, but broadly refers to materials that generate eddy currents by electromagnetic induction, but it should be selected in consideration of thermal conductivity, required mechanical strength, workability, corrosion resistance, economical efficiency, etc. .

The induction heating coil is formed by winding a general material, for example, a rectangular copper wire in a spiral shape, and is wound in an oval shape or a rectangular shape. The side portion (the linear portion in the longitudinal direction) has an angle with the steel belt flow direction of 45 degrees or more and 135 degrees or less, preferably 60 degrees or more and 120 degrees or less,
More preferably, it is installed so as to be 85 degrees or more and 95 degrees or less. It is most preferable to install the coil so that the longitudinal direction of the coil and the steel belt flowing direction are orthogonal to each other, but in consideration of the conveying speed of the steel belt conveyor, the angle between the longitudinal direction of the coil and the steel belt flowing direction is 45 degrees or more. If so, the food can be heated uniformly. Coil material,
The number of turns depends on the method widely used for induction heating coils.

The length of the linear portion of the coil is basically required to be equal to or larger than the width required for uniformly heating the object to be heated, out of the width of the steel belt, but the belt crosses the width direction. If the temperature distribution along the straight line is large, the difference in expansion amount between the high temperature portion and the low temperature portion becomes large, and the belt surface may be distorted. The distortion causes the distance from the coil to deviate from a predetermined value. Induction heating that is not at an appropriate distance further causes a temperature distribution, which leads to a vicious cycle in which distortion is increased.

In order to prevent this distortion, it is desirable that the length of the straight portion of the coil exceeds the width of the steel belt so that only the straight portion of the coil is used for induction heating. The high-frequency current flowing in the coil straight line portion produces an almost uniform eddy current in the portion along the straight line that crosses the belt in the width direction. The shape of the heating portion is almost straight, and the heating state is uniform over the width direction of the belt. At both ends of the coil and the portion protruding from the belt, it is advisable to take measures such as bending in the opposite direction of the belt on the outside of the belt to prevent unnecessary heating of nearby metal parts.

By uniformizing the surface temperature of the belt in the width direction, foods that emphasize the baking color and browning of the baking surface, such as hamburger, dumplings, baked rice balls, dorayaki, okonomiyaki, omelet, etc., have a uniform baking color. It has become possible to produce extremely high-quality and uniform food products, synergistically with the controllability of induction heating.

As described above, according to the present invention, since it is not necessary to oscillate the coil in order to make the heating uniform, the oscillating setting is calculated by the conventional surface temperature distribution measurement, and the oscillating is accurately performed accordingly. It is excellent in terms of cost and durability because it eliminates the hassle of making it, and has a simple structure.

As the output control method of the induction heating coil, a widely used method can be adopted. For example, a contact type or radiation type thermometer detects the steel belt surface temperature or the ambient temperature of any part,
It is a method of adjusting the coil output by feedback control.

Furthermore, it is possible to add a device capable of steaming and heating a part or all of the steel belt conveyor. In this case, cooking by steaming and coloring with baking can be performed in one step, and it can be used for more foods.

It is also possible to install a spray nozzle at one place or two or more places above the steel belt conveyor and add a device for spraying a liquid such as water or hot water. In this case, there is an effect of replenishing water lost by heating from the belt surface, preventing excessive drying of food, and suppressing deterioration of quality.

Of course, it is also possible to combine an apparatus capable of boiling and heating with an apparatus capable of spraying liquid. In this case, for example, suitable for baking dumplings, the cooking of noodles and fillings is proceeded by steaming, the drying and solidification of the noodles, especially the ears, are prevented by spraying water or hot water, and induction heating of the belt surface causes uneven baking. It is possible to achieve a uniform burnt surface. In this way, high-quality gyoza, stable, automatic,
Up to now, there has not been a food heating device capable of continuous large-scale cooking.

The present invention is intended for a steel belt conveyor as a heating surface which also serves as a conveyor, but is applicable to an apparatus using a plate conveyor. The plate conveyor refers to a mechanism for continuously driving the grill plate. As a drive mechanism for the grill, a chain is provided at both ends of the grill, or at multiple locations on both ends and in the middle, and the grills are connected to the drive chain side by side, and the grill is driven together with the drive chain, or the top of the drive chain. It is possible to use a mechanism in which the grill plates arranged in the above are hooked and fed by a feed claw attached to a drive chain, or a mechanism in which the grill plates are placed on a roller conveyor and the drive rollers rotate to feed the grill plates.
When a plate conveyor is used, it is not necessary to bend the grill plate during driving, so a thick metal plate can be used so that it does not bend due to its own weight and thermal strain, and the plate thickness is 2 mm. It is preferably from 10 to 10 mm.

Although the above description has dealt with the food heating device as a specific example, the present invention is not limited to the food, but various heat treatment devices such as rubber and synthetic resin heat treatment, and metal material aging. It is widely available for

[0018]

BEST MODE FOR CARRYING OUT THE INVENTION Next, an embodiment of the present invention as a food heating device will be described in detail with reference to the drawings. Figure 1
Fig. 1 is a side view of the food heating device 1 of the present invention. Here, since various detailed parts as the device are appropriately designed within the scope of the present invention, the drawings in principle show the entire structure of the device. As shown in FIG. 1, in the food heating device 1 of the present invention, a steel belt 3 is hung between two drive pulleys 2. The steel belt surface, specifically, the outer upper surface of the steel belt 3 is heated. 5
Of the conveyor belt, and below the steel belt 3,
The induction heating coil 4 is installed at an appropriate distance from the steel belt.

FIG. 2 is a perspective view of a portion where the induction heating coil is installed. In fact, the induction heating coil 4 is installed below the steel belt 3. As the induction heating coil 4, for example, as shown in FIG. 2, it is preferable to use a rectangular shape having a long side (a linear portion of the coil) longer than the width of the steel belt 3. With this arrangement, only the straight portion of the coil induction-heats the steel belt, and uniform heating is performed along the width direction of the steel belt.

In such a food heating device 1, for example, the object 5 to be heated continuously supplied onto the steel belt 3 from the inlet pulley side is subjected to heat treatment such as baking while passing through the induction heating coil 4. And is continuously taken out from the outlet pulley side. At this time, it is also possible to provide a means for supplying and a means for discharging the article to be heated 5 at both ends of the food heating apparatus 1 so as to continuously and automatically operate.

FIG. 3 shows a food heating device 8 with a steam heating device, which is a combination of the food heating device 1 and a tunnel steamer 6 as a steaming means. The object 5 to be heated is cooked while being steamed and cooked while passing through the steamer 6, while the induction heating coil 4 heats the surface of the steel belt to be cooked.
The length of the portion occupied by the steaming cabinet 6 is a part or the whole of the length of the food heating device 8, and may be determined depending on the cooking characteristics of the article to be heated 5. In addition, steam cooking and baking cooking may be performed simultaneously or separately. Also for this, the condition may be determined depending on the cooking characteristics of the article to be heated 5.

In FIG. 4, in addition to the food heating device 8 with a steam heating device, a spray nozzle 7 for spraying a liquid such as water or hot water can be sprayed from above while the object 5 to be heated is passing. The arranged food spraying device and food heating device 9 with a steam heating device are shown. The object 5 to be heated is a steamer 6
While being steamed and cooked while passing through, the spray nozzle 7 further sprays water or hot water, and the induction heating coil 4 heats the steel belt surface 3 to bake and cook. There may be a device without the steamer 6 and with only the spray nozzle 7. When performing the spraying inside the steaming cabinet 6, when performing the spraying outside the steaming cabinet 6, there are cases where the spraying is performed at both sides.
Further, the installation position of the induction heating coil 4 and the spray nozzle 7
The relationship of the installation positions of is also arbitrary. These are all determined by the cooking characteristics of the article to be heated 5.

[0023]

EXAMPLE As shown in FIG. 2, two long elliptical coils are set as one set and the longitudinal direction of the coil is arranged orthogonal to the belt traveling direction (the present invention), and three long elliptical coils are taken as one set. When the coils are arranged so that the coil longitudinal direction is the belt advancing direction (Comparative Example 1), the coil longitudinal direction is the belt advancing direction and the coils are rocked by the air cylinder (Comparative Example 2) ), The temperature distribution on the belt surface during rotation of the steel belt is measured by "thermography".
(Manufactured by Nippon Avionics Co., Ltd.). Comparative Example 1
In FIG. 6, there was apparently temperature unevenness in the belt width direction. Further, in Comparative Example 2 (FIG. 7) in which the coil was swung in order to eliminate the temperature unevenness, the temperature unevenness in the width direction could not be eliminated. As shown in FIG. 5, in the arrangement of the present invention, no temperature unevenness in the width direction is observed, and the displayed color transition is also orthogonal to the belt traveling direction, and uniform heating in the belt width direction is realized. It was Further effective heating width 350
FIGS. 8 and 9 show photographs when the gyoza were continuously baked so that ten pieces were arranged in the width direction on a belt having a size of 10 mm. In the arrangement of the present invention (FIG. 8), the baking color was uniform in the width direction without unevenness of the baking color depending on the placement location.

[0024]

According to the present invention, the following excellent effects can be obtained. In a food heating device with a steel belt conveyor as a heating surface that also serves as a conveyor, and an induction heating coil installed at the bottom or top of the steel belt,
The induction heating coil is oval or rectangular, and the longitudinal direction of the coil and the steel belt flow direction are 45 degrees or more.
By setting the temperature so that it is less than or equal to the temperature, heating in the belt width direction can be made uniform. Further, by making the length of the induction heating coil in the longitudinal direction longer than the width of the steel belt, only the magnetic field from the linear portion of the coil influences, so that the homogenization can be easily realized. By making the surface temperature of the belt uniform in the width direction, it becomes possible to uniformize the baking color of foods that emphasize baking color and browning of the baking surface, such as hamburger, dumplings, grilled rice balls, dorayaki, okonomiyaki, omelet. The synergistic effect with the controllability of induction heating enables the production of extremely high quality and uniform products.

[Brief description of drawings]

FIG. 1 is a side view showing the entire food heating device of the present invention.

FIG. 2 is a perspective view of a coil portion viewed from above.

FIG. 3 is a side view of a food heating device to which steaming means is added.

FIG. 4 is a side view of a food heating device to which steaming means and spraying means are added.

FIG. 5 is a temperature distribution when the coil longitudinal direction is arranged so as to be orthogonal to the belt traveling direction.

FIG. 6 is a temperature distribution in the case where the coil longitudinal direction is arranged in the belt traveling direction.

FIG. 7 is an example of temperature distribution when the coils are arranged so that the longitudinal direction thereof is the belt traveling direction and the coils are rocked by an air cylinder.

FIG. 8 is a photograph when dumplings are continuously baked with the arrangement of the present invention (the vertical direction is the belt width direction)

FIG. 9 is a photograph when dumplings are continuously baked in the arrangement of the comparative example (the vertical direction is the belt width direction)

[Explanation of symbols]

1 Food heating device 2 Drive pulley 3 steel belt 4 induction heating coil 5 Heated object 6 steamer 7 spray nozzles 8 Food heating equipment with steaming means 9 Food heating device with steaming means and spraying means

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[Procedure amendment]

[Submission date] May 27, 2002 (2002.5.2)
7)

[Procedure Amendment 1]

[Document name to be amended] Statement

[Name of item to be amended] Claims

[Correction method] Change

[Correction content]

[Claims]

[Procedure Amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0004

[Correction method] Change

[Correction content]

[0004]

However, in order to make uniform, it is necessary to set the fluctuation calculated from the heating distribution at rest, and even if the setting is calculated, the air cylinder, the cam, etc. The simple reciprocal rocking of provides uniform heating
It is difficult to realize the setting of the swing for obtaining the result, and as a result, there is a problem that the homogenization cannot be realized unless an expensive system is combined with a thermography, a computer, a servomotor, and the like.

[Procedure 3]

[Document name to be amended] Statement

[Correction target item name] 0008

[Correction method] Change

[Correction content]

Width direction of the steel belt of the straight portion of the coil
The length of is basically the width of the steel belt that is greater than or equal to the width required to uniformly heat the object to be heated, but the temperature distribution along a straight line that crosses the belt in the width direction. Is large, the difference in expansion amount between the high temperature portion and the low temperature portion becomes large, and the belt surface may be distorted. The distortion causes the distance from the coil to deviate from a predetermined value. Induction heating that is not at an appropriate distance further causes a temperature distribution, which leads to a vicious cycle in which distortion is increased.

[Procedure amendment 4]

[Document name to be amended] Statement

[Correction target item name] 0009

[Correction method] Change

[Correction content]

In order to prevent the distortion, the length of the straight portion of the coil in the width direction of the steel belt exceeds the width of the steel belt, and the straight portion of the coil is generated.
It is desirable that only the magnetic field used is used for induction heating. The magnetic field generated by the high-frequency current flowing in the coil straight section is
A substantially uniform eddy current is generated in a portion along a straight line that crosses the belt in the width direction. The shape of the heating portion is almost straight, and the heating state is uniform over the width direction of the belt. At both ends of the coil and the portion protruding from the belt, it is advisable to take measures such as bending in the opposite direction of the belt on the outside of the belt to prevent unnecessary heating of nearby metal parts.

[Procedure Amendment 5]

[Document name to be amended] Statement

[Correction target item name] 0013

[Correction method] Change

[Correction content]

Further, it is possible to add a device capable of steaming and heating food to a part or all of the moving direction of the steel belt conveyor. In this case, cooking by steaming and coloring with baking can be performed in one step, and it can be used for more foods.

[Procedure correction 6]

[Document name to be amended] Statement

[Correction target item name] 0014

[Correction method] Change

[Correction content]

Further, the upper in one place or two or more places in the moving direction <br/> of steel belt conveyor, the spray nozzle is installed, it is also possible to add a device for spraying a liquid such as cold water or hot water. In this case, there is an effect of replenishing water lost by heating from the belt surface, preventing excessive drying of food, and suppressing deterioration of quality.

[Procedure Amendment 7]

[Document name to be amended] Statement

[Correction target item name] 0018

[Correction method] Change

[Correction content]

[0018]

BEST MODE FOR CARRYING OUT THE INVENTION Next, an embodiment of the present invention as a food heating device will be described in detail with reference to the drawings. Figure 1
Fig. 1 is a side view of the food heating device 1 of the present invention. Here, since various detailed parts as the device are appropriately designed within the scope of the present invention, the drawings in principle show the entire structure of the device. As shown in FIG. 1, in the food heating device 1 of the present invention, a steel belt 3 is hung between two drive pulleys 2. The steel belt surface, specifically, the outer upper surface of the steel belt 3 is heated. 5
Of the conveyor belt, and below the steel belt 3,
The induction heating coil 4 is installed at an appropriate distance from the steel belt 3 .

[Procedure Amendment 8]

[Document name to be amended] Statement

[Correction target item name] 0019

[Correction method] Change

[Correction content]

FIG. 2 is a perspective view of a portion where the induction heating coil 4 is installed. In fact, the induction heating coil 4 is installed below the steel belt 3. As the induction heating coil 4, for example, as shown in FIG. 2, it is preferable to use a rectangular shape having a long side (a linear portion of the coil) longer than the width of the steel belt 3. This arrangement, only the straight portions of the coil 4 is a steel belt 3 and induction heating, along the width direction of the steel belt 3, uniform heating is performed.

[Procedure Amendment 9]

[Document name to be amended] Statement

[Name of item to be corrected] Brief description of the drawing

[Correction method] Change

[Correction content]

[Brief description of drawings]

FIG. 1 is a side view showing the entire food heating device of the present invention.

FIG. 2 is a perspective view of a coil portion viewed from above.

FIG. 3 is a side view of a food heating device to which steaming means is added.

FIG. 4 is a side view of a food heating device to which steaming means and spraying means are added.

FIG. 5 is a temperature distribution when the coil longitudinal direction is arranged orthogonal to the belt traveling direction (example of the present invention).

FIG. 6 is a temperature distribution in the case where the coil longitudinal direction is arranged in the belt traveling direction (Comparative Example 1).

FIG. 7 is a temperature distribution when the coil is arranged so that the longitudinal direction thereof is the belt traveling direction and the coil is rocked by an air cylinder (Comparative Example 2).

FIG. 8 is a photograph when dumplings are continuously baked with the coil arrangement of the present invention (the vertical direction is the belt width direction).

FIG. 9 is a photograph of dumplings continuously baked with the coil arrangement of Comparative Example 1 (the vertical direction is the belt width direction).

Continued front page    (72) Inventor Hiroshi Takahashi             Gunma Prefecture Ora-gun Oizumi-cho large character 1222 Yoshida taste             Nomoto Frozen Food Co., Ltd (72) Inventor Hirofumi Terasaki             Gunma Prefecture Ora-gun Oizumi-cho large character 1222 Yoshida taste             Nomoto Frozen Food Co., Ltd F term (reference) 3K051 AA08 AC33 AD05 CD42 CD43                 3K092 PP03 QA04 VV22 VV23                 4B040 AA08 AD22 CA06 CA12

Claims (4)

[Claims] 1. A food heating apparatus comprising a steel belt conveyor as a heating surface which also serves as a conveyer, and an induction heating coil installed at a lower portion or an upper portion of the steel belt, wherein the induction heating coil is oval or rectangular, and the length of the coil is long. The food heating device is installed such that an angle between the direction of the steel belt and the flow direction of the steel belt is 45 degrees or more and 135 degrees or less. 2. The food heating device according to claim 1, wherein a distance in the width direction of the steel belt of the induction heating coil is longer than a width of the steel belt when installed. 3. The food heating device according to claim 1, wherein a device capable of steaming and heating is added to a part or all of the steel belt conveyor. 4. The food heating device according to claim 1, wherein a device capable of spraying a liquid is added to one or more places above the steel belt conveyor.