JPWO2006080233A1 - Beverage can induction heating device and induction heating method - Google Patents

Abstract

  A metal beverage can in which a screw portion is formed in the mouth portion having a diameter smaller than that of the can body portion, a cap portion is formed by tightening a cap around the screw portion, and the cap portion can be resealed. Is an induction heating apparatus for beverage cans, which has a can holder for holding a can, and an induction heating coil is arranged on the outer peripheral side of the can holder. The can holder has a can locking portion, and by locking the beverage can by the can locking portion, the beverage can is held in either the upright state or the inverted state, and The induction heating coil is arranged only outside the side surface of the can body portion of the beverage can excluding the cap portion.

Description

  The present invention relates to an induction heating device and an induction heating method for heating a can filled with a beverage by electromagnetic induction heating.

  BACKGROUND ART At present, a beverage can warming device, which is often used in convenience stores and the like, is configured to house a plurality of beverage cans inside a glass case or the like to heat and keep warm to a predetermined temperature. Therefore, when the customer desires a warm beverage can, the desired beverage can is taken out from the warming device and purchased. In this type of heat retention device, the temperature of the internal atmosphere such as the inside of the glass case is raised to a predetermined temperature, and the beverage can is housed in the temperature atmosphere. Therefore, in order to heat and raise the temperature of the beverage can and keep it warm, it is necessary to constantly energize the heat generating device provided in the heat retaining device, which continuously consumes energy, resulting in a running cost problem. Further, when kept at a predetermined temperature, the oxidative reaction between oxygen in the can and components in the beverage (vitamin C, starch, etc.) is promoted (oxidatively modified), so that the beverage can is filled. Deterioration of the color, aroma, taste, etc. of the beverage progresses. Therefore, it is not possible for the seller to display the beverage cans in a warm state for a long time. Therefore, there has been proposed a beverage can heating device that quickly warms a beverage can at the point of sale of the customer, that is, at the time of sale.

  As such a heating device, there is known a heating device that includes a can holder for holding a beverage can and arranges a heating coil for inductively heating the beverage can around the can holder to heat the can. (See JP 2002-245535A, JP 09-097379A, JP 07-325971A). In such a type of heating device, as described in JP-A-2002-245535 and JP-A-07-325971, it is easy to insert a can into and from a can holder. In some cases, the height (length) of the can holder is determined so that the upper part of the can projects from the can holder. In this case, the height (length) of the can holder is the highest among the cans to be heated and sold in order to accommodate various cans with different heights (lengths). It is set to suit the smallest (shortest) can container. In that case, in order to reliably and efficiently perform heating so as to reach the desired can temperature in a short time, as a heating element installed around the can holder, the entire area in the height direction from the top to the bottom of the can holder is used. In many cases, a heating coil is provided over the entire length, and the can body portion held by the can holder is heated over almost the entire area in the height direction. Further, as described in Japanese Patent Application Laid-Open No. 09-097379, in a device configured to discharge a heated beverage can from a can holder by an arm for discharging a beverage can, a height (length) In order to accommodate various beverage cans of different types, if the heating coil is arranged so that the entire can body of the beverage can with a high (long) can height (length) is heated, When a beverage can having a short (short) length is heated, heating is performed to a portion where the can body does not exist, and heating efficiency is reduced. Therefore, the heating coil is often arranged according to the can body of a beverage can having a low (short) can height (length). That is, in a beverage can induction heating device, a beverage coil having a high can length (length) is provided by a heating coil arranged to match the can body of a beverage can having a low (short) can height (length). Since it is necessary to heat the can, it is desirable to make the heating efficiency as high as possible.

  As a can container for a beverage can heated by such a beverage can induction heating device, in recent years, a screw portion is formed at a drinking mouth portion, and a screw cap made of metal is screwed into the container to open it once and then re-install it. Resealable cans that can be sealed are in circulation.

  Such a reseal can is used as a container for various beverages, and is particularly convenient as a container for heating and selling coffee beverages, tea beverages, and the like. This is because the inside diameter of the mouth of a reseal can is larger than that of a conventional can with an easy open end wrapped around it, making it easier to drink a heated beverage or selling such a beverage after it has been heated. In this case, consumers rarely drink all at once and there is a high demand for resealing.

  This reseal can has an outer diameter of the can body which is conventionally used for convenience of the distribution process, that is, in order to facilitate the handling of the product when it is boxed, packed, transported, or displayed on a product shelf at a store. It is set almost the same as a can. As a portion connected to the can body, a shoulder portion having a tapered or hemispherical diameter and a mouth portion having a screw portion and a curl portion are formed. Then, a resin coating film or a coating film by painting is formed on the inner surface and the outer surface thereof, and a metal cap is attached and sold with the contents filled.

  Therefore, the reseal can can be held on the can holder of the beverage can heating device that has been conventionally used, so that it is possible to heat the reseal can without particularly modifying the existing beverage can heating device. ..

  However, in the beverage can induction heating device as described in JP-A No. 2002-245535, JP-A No. 09-097379, and JP-A No. 07-325971, the operator mistakenly detects that the cap portion of the reseal can is When the can is placed so that it comes to the bottom side of the can holder (inverted state), when the can is placed so that the cap part of the reseal can comes to the opening side of the can holder (normal state) In comparison, there is a problem that the heating capacity and the heating efficiency are reduced. In other words, since the can body of the conventional can has a substantially columnar shape, even when the can is held so that the drinking mouth comes to the opening side of the can body holding part (normal position), it can come to the bottom side of the can body holding part. The heating capacity and heating efficiency do not change so much even when held in a closed state (inverted state), whereas the resealing can has a smaller diameter at its mouth and shoulder than the neck of a conventional can. Since it is large, the distance between the heating coil and the surface of the can becomes large at these mouths and shoulders (see FIG. 7). The configuration shown in FIG. 7 will be described later.

  As the distance between the heating coil and the surface of the can increases, the effect of electromagnetic induction decreases and the generated induction current decreases, so if the reseal can is heated in the inverted position, the reseal can cannot be heated to the desired temperature. Alternatively, there is a problem that the heating capacity and the heating efficiency are deteriorated, for example, the heating takes too long.

  Further, when the reseal can is thrown in the inverted state, the cap portion with the screw is heated. In this case, since the screw cap portion is located far from the heating coil as described above, the induced current generated is small and the amount of heat generation is not larger than that of the can body portion. However, the cap is screwed into the mouth portion, and the cylindrical portion of the cap or the cylindrical portion formed with the female screw is in direct contact with the beverage filled in the can container. Absent. Therefore, the heat generated by the electromagnetic induction at the outer peripheral portion of the cap portion is hard to be transmitted to the surroundings, and the temperature easily rises excessively even if the amount of generated heat is not large. As a result, the resin coating or coating on the inner surface of the cap may be thermally deteriorated and damaged, or the frictional resistance between the outer surface of the screw and the inner surface of the cap may increase, making it difficult to open the cap, discoloring or burning. Is likely to occur, resulting in a poor appearance. In addition, although the inner surface of the screw part of the reseal can is in direct contact with the beverage in the container, the part in contact with the cap part whose temperature has risen excessively is not affected by the heat of the cap part. easy. Therefore, the flavor of the contents is deteriorated, or the resin coating or coating film in the portion in contact with the cap portion is thermally deteriorated, and there is a problem in terms of corrosion resistance, etc. The same troubles will occur.

  The object of the present invention is not to reduce the heating efficiency and heating ability even if the resealing can is put in either the upright state or the upside down state, and the inner surface of the cap portion and the outer surface of the screw portion of the resealing can mouth portion. Excessive temperature rise may damage the resin coating or coating due to thermal deterioration, or the resin on the screw outer surface of the reseal can and the resin on the inner surface of the cap may melt and make it difficult to open the cap, or cause discoloration. (EN) A beverage can heating device and a beverage can heating method capable of heating a resealed can beverage while preventing the occurrence of charring and poor appearance, and excellent operability. In this specification, the upright state refers to a state where the bottom of the reseal can faces the bottom of the can holder of the induction heating device, and the inverted state refers to the bottom of the can holder. , The state where the cap portion of the reseal can faces.

  In addition, the products that are heated and sold include thickened contents such as porridge, cream stew, and potage soup. Such contents have low viscosity because the liquid portion of the contents has a high viscosity and some solids are mixed, so that the fluidity is low. When a beverage can filled with such a highly viscous content or a low-fluidity content is heated by induction heating, the content is difficult to stir even if induction heating is performed while the can is rotated. It is difficult to transfer heat to the contents, and the contents may burn to the inner surface of the can body. It is an object of the present invention to provide a heating device and a heating method that do not cause sticking on the inner surface of the can body even when the above highly viscous contents are heated. The contents of the beverage can targeted by the present invention include, in addition to the contents composed of only liquid, the above-mentioned porridge, cream stew, contents such as potage soup in which liquid and solid are mixed. Including.

  Further, the contents with high viscosity as described above are less likely to be stirred even if induction heating is performed while rotating the can, so that heat generated in the can body due to induction heating is not easily transferred to the contents rapidly. Therefore, the temperature of the surface of the can body becomes high, and when the heating is completed and the beverage can is taken out from the can holder, it may be too hot to hold with a bare hand, or the hand may be burned. The present invention provides a beverage can heating device and a heating method in which the surface temperature of the can body does not become excessively high even when the highly viscous contents are heated, and the beverage can is easily taken out from the can holder after the heating is completed. The purpose is to do.

  In order to achieve the above-mentioned object, the induction heating device for a beverage can of the present invention has a can holder for holding the beverage can and an induction heating coil arranged on the outer peripheral side of the can holder. The can holder has a can body holding portion having an inner diameter larger than the body outer diameter of the beverage can and having a predetermined height, and a can locking portion projecting inward of the can holding body. .. The can that is put into the can holder is entirely made of metal, and a screw portion is formed at the mouth portion that is reduced in diameter from the can body portion, and the cap portion is tightened by winding the cap around the screw portion. A reseal can is formed that is resealable by its cap portion. The can locking portion contacts the bottom of the reseal can and prevents passage of the reseal can through the can body when the reseal can is inserted into the can holder in a direction in which the resea can is in the normal position. And the amount of protrusion of the can locking portion inwardly of the can holder is smaller than the difference between the outer radius of the can body and the outer radius of the cap. In addition, when the reseal can is inserted into the can holder in a direction in which the reseal can is inverted, the cap portion can pass through. As a result, the heating device of the present invention, the resealing can, in a state of being held in any of the upright state or the inverted state, the induction heating coil outside the side surface of the reseal can excluding the cap portion. It is characterized in that it is configured so as to be positioned only.

  Also, in the induction heating device for a beverage can of the present invention, the heating coil is relatively densely wound between the opening side of the can body holding portion and the can locking portion side, and the opening side and the can engaging member. It is characterized in that it is wound so as to be relatively rough at the central portion between the stop portion side.

  Further, the induction heating method of the beverage can of the present invention, while rotating the beverage can by the rotating mechanism in a state where the beverage can is held by the can holder, the beverage by the induction heating coil arranged on the outer peripheral side of the can holder. A method of induction heating a can, wherein the beverage can is held and rotated in a state of being inclined at a predetermined angle with respect to a vertical line, and from the start of the rotation of the beverage can until the end of the rotation. In addition, the method is characterized in that the beverage can is rotated by alternately repeating the increase of the rotation speed of the beverage can and the decrease of the rotation speed of the beverage can.

  Further, the method of induction heating the beverage can of the present invention, while rotating the beverage can by alternately repeating the increase and decrease of the rotation speed as described above, starts the induction heating after starting the rotation of the beverage can. After heating the beverage can, the induction heating is stopped, the beverage can is rotated for a predetermined time in a state where the induction heating is not performed, and then the rotation of the beverage can is stopped.

  Moreover, the method for induction heating a beverage can of the present invention is a method characterized in that, in addition to the above-described configuration, induction heating is intermittently performed.

  With the above configuration, the beverage can induction heating device of the present invention is either a conventional cylindrical beverage can or a reseal can having a cap screwed into the cylindrical mouth portion. However, it can be charged into the can holder in a direction in which the central axis of the beverage can and the central axis of the can holder are the same. Further, since the can retaining portion is formed on the can holder, the can body portion cannot be pushed deeper than the can retaining portion, and is held by the can body retaining portion, and therefore, the outer side of the can body retaining portion is maintained. The installed heating coil efficiently heats the barrel of the can. Further, the protrusion amount of the can locking portion (the protrusion amount inward in the direction perpendicular to the inner surface of the can body holding portion) is formed to be smaller than the difference between the outer radius of the can body portion and the outer radius of the cap portion. Thus, when the reseal can is thrown in the inverted state, the cap portion passes through the can locking portion and is held below the can body holding portion. Therefore, the induction heating coil is not located outside the cap portion. In this way, since the induction heating coil is arranged so as to be located only on the outer side of the side surface of the reseal can excluding the cap portion, the beverage can is held in either the upright state or the inverted state. Also, it is possible to heat efficiently. Also, since the cap part of the reseal can is not heated more than necessary, the resin coating and coating film on the inner surface of the cap part and the outer surface of the screw part of the mouth part are thermally deteriorated even when the reseal can is thrown in an inverted state. Due to damage, or increase in frictional resistance between the screw outer surface of the mouth and the inner surface of the cap, or the fusion of resin coatings between the inner surface of the cap and the outer surface of the screw of the mouth. It is possible to avoid problems such as making it difficult to open the cap and causing discoloration or scorching to deteriorate the appearance.

  Further, according to the beverage can induction heating device of the present invention, since the heating coil is wound so as to be rough at the central portion between the opening side and the can locking portion side, the opening side and the can engaging member Even if the magnetic flux generated from the coil on the stop side reaches the central part and interferes with the magnetic flux generated from the heating coil in the central part, the magnetic flux density becomes maximum in the central part and becomes excessive near the center of the can body holding part. No fever is generated. Therefore, the resin coating or coating on the inner surface of the can body is thermally deteriorated, the components of the resin coating or coating are eluted into the contents, or the resin coating or coating peels off or cracks, and the Problems such as deterioration of the quality of the contents due to the elution of the metal component into the contents are prevented. Further, it is possible to prevent a problem that the outer surface of the can body is printed, the adhesive film, the shrink film, etc. are thermally deteriorated, and the appearance of the can body is deteriorated due to the discoloration or peeling of the film.

  Further, according to the induction heating method of the present invention, the beverage can is held and rotated in a state inclined by a predetermined angle with respect to the vertical line, whereby the content becomes a turbulent state and the content is agitated. The effect can be enhanced. Further, since the rotation speed of the beverage can is repeatedly increased and decreased between the start of the rotation of the beverage can and the end of the rotation, the effect of stirring the contents is enhanced. That is, the contents rotate when the beverage can rotates, but the contents rotate due to the friction between the contents and the inner surface of the can in the area that contacts the inner surface of the beverage can, and the rotation is transmitted to the entire contents. Thereby, the entire contents are rotated and stirred. Therefore, it takes some time from the start of rotation of the beverage can until the entire contents rotate at a constant rotation speed. Therefore, when the rotation speed of the beverage can is changed, there is a difference in the rotation speed between the content in the vicinity of the inner surface of the beverage can and the content in the center of the beverage can, so that the content is in a turbulent state. The stirring effect is further enhanced. Therefore, even when a beverage can filled with a highly viscous content is heated, the content does not stick to the inner surface of the can. Further, since the heat generated in the can body is satisfactorily transferred to the contents, the surface of the beverage can does not become excessively hot, and the beverage can is easily taken out after the heating is completed.

  In the present invention, in the section where the rotation speed is increased and the section where the rotation speed is decreased, the rotation speed may be constant in a part of the section in addition to continuously increasing or decreasing the rotation speed.

  Further, in the induction heating method of the present invention, after starting the rotation of the beverage can to start the induction heating, after heating the beverage can, the induction heating is stopped, the beverage can for a predetermined time without performing the induction heating. By rotating, the heat of the heated beverage can is transferred to the contents, the temperature of the surface of the beverage can is lowered, and the temperatures of the beverage can and the contents are homogenized. Therefore, it becomes easy to take out the beverage can from the can holder after the rotation of the beverage can is stopped.

  In addition, in the induction heating method of the present invention, it is possible to prevent the contents from sticking to the inner surface of the can by intermittently performing the induction heating. That is, from the start of heating to the end of heating, a heating section in which the beverage can is induction-heated and a non-heating section in which the beverage can is not induction-heated are alternately repeated. Therefore, the heat generated in the metal part of the beverage can during the induction heating is transferred to the contents while the induction heating is not performed, and the temperature of the beverage can decreases, so that the temperature of the beverage can rises excessively. The contents can be prevented from sticking to the inner surface of the can. Further, the surface of the beverage can does not become excessively hot, and the beverage can is easily taken out from the can holder after the heating is completed.

FIG. 1 is a diagram showing an example of a beverage can heating device according to the present invention, and is a cross-sectional view schematically showing an internal structure in a state in which a reseal can is held in an inverted state.
FIG. 2 is a cross-sectional view schematically showing a can holder that holds the reseal can in a normal position.
FIG. 3 is a sectional view schematically showing a can holder that holds a reseal can in an inverted state.
FIG. 4A is a partial cross-sectional view showing an example of the winding structure of the litz wire in the heating coil.
FIG. 4B is a partial cross-sectional view schematically showing the number of windings and the winding density of the litz wire in the heating coil.
FIG. 5: is a figure which shows an example of the aspect of rotation of the can holder in the induction heating apparatus of the beverage can of this invention.
FIG. 6 is a diagram showing an example of a heating mode in the beverage can induction heating device of the present invention.
FIG. 7 shows a conventional can holder, and is a cross-sectional view in a state where a reseal can is held in an inverted state.

  Hereinafter, the best mode for carrying out the present invention will be described with reference to the drawings.

  FIG. 1 shows an embodiment of an induction heating device for a beverage can according to the present invention, and is a cross-sectional view schematically showing the internal structure of the beverage can heating device with the reseal can being held in an inverted state. FIG. 2 is a view showing a state in which a reseal can is held in a normal position on a can holder of the present invention, and FIG. 3 is a view showing a state in which a reseal can is held in an inverted state on a can holder of the present invention. ..

  Further, FIG. 4A is a partial cross-sectional view showing an example of the winding structure of the litz wire in the heating coil of the induction heating device for a beverage can of the present embodiment, and FIG. 4B is the winding of the litz wire in the heating coil. It is a fragmentary sectional view which shows the state of number and winding density typically. Further, FIG. 5 is a diagram showing an example of a mode of rotation of the can holder in the induction heating device for a beverage can of the present embodiment, and FIG. 6 is a diagram showing an example of a mode of induction heating.

  In FIG. 1, in a box-shaped main body case 1, the central axis A of the can holder 3 is placed with a cylindrical can holder 3 holding a beverage can 2 such as a reseal can tilted at a predetermined angle. A motor 4 is installed rotatably in the center, and below the bottom part thereof is a rotating mechanism for rotating the can holder 3. On the opening side of the can holder 3, a can body holding portion 5 having an inner diameter larger than the outer diameter of the can body of the held beverage can 2 by a predetermined length is provided, and the beverage can 2 is induction-heated on the outer periphery thereof. The heating coil 6 is installed. The height (length in the central axis A direction) of the can body holding portion 5 is equal to or more than half the height of the can body portion of the beverage can 2 to which it is applied. The length is less than or equal to) is preferable. If the height of the can body is less than one half, the beverage can 2 cannot rotate stably when the can body holding portion 5 is rotated, which is not preferable. In order to rotate the beverage can 2 in a more stable manner, it is more preferable to set the height to 2/3 or more of the height of the body of the beverage can 2. Further, if the height of the can body holding portion 5 is equal to or higher than the height of the beverage can 2, there is a problem that it is difficult to load and unload the beverage can 2, which is not preferable.

  4A and 4B show an example of the structure of the heating coil 6 used in the present invention. For the heating coil 6, it is preferable to use a litz wire formed by twisting a plurality of copper wires as an electric wire for passing an electric current. Further, as shown in FIG. 4A, the heating coil 6 can be divided into a region 6A near the opening side of the can body holding portion 5, a region 6B near the center, and a region 6C near the can locking portion 7. As shown in FIG. 4B, the number of windings of the electric wire (the number of times the electric wire is wound around the outer circumference of the can body holding portion) in each of the area 6A close to the opening side and the area 6C close to the can locking portion 7 It is preferable that the heating coil 6 is formed by increasing the number of windings so that the heating coil 6 is wound densely, reducing the number of windings in the region 6B near the center, and winding it roughly. When the heating coil 6 is formed by winding the copper wire evenly, the magnetic flux generated from the heating coil 6 on the opening side and the can locking portion 7 side reaches the central portion as well, and the magnetic flux generated from the heating coil 6 on the central portion overlaps with the magnetic flux. By walking, the magnetic flux density is maximized in the central portion, so that a large induced current is generated in the can body near the center of the can body holding portion 5. As a result, a larger amount of heat is generated near the center of the can body holding portion 5, so that the resin film or coating film on the surface of the can body near the center is thermally deteriorated to deteriorate the quality of the contents or the appearance of the can body. Deteriorating problems occur. On the other hand, by reducing the number of windings of the heating coil 6 near the center of the can body holding portion 5, the magnetic flux generated from the heating coil 6 near the center is reduced, and an excessive amount of heat is generated near the center of the can body holding portion 5. It is possible to suppress uniform heating and perform uniform heating. Further, it is possible to prevent deterioration of quality and appearance of the contents due to heat deterioration of the resin coating film or coating film on the surface of the can body. In particular, when a heat-shrinkable shrink label is attached to the outer surface of the can, it is possible to effectively prevent excessive heat generation of the can body near the center of the heating coil 6 and breakage of the shrink label due to this.

  Further, it is preferable that the number of windings is gradually reduced from the opening side or the can locking portion 7 side toward the central portion of the heating coil 6. According to this structure, since the induced current generated in the can body is homogenized, an effect of preventing excessive heat generation in the can body in the vicinity of the central portion of the heating coil 6 as described above or a problem accompanying it. In addition, the beverage inside can be heated evenly. Also, the number of windings per unit length in the can axis (center axis of the can body) (referred to as winding density) is close to the area 6a near the opening side of the can body holding portion 5 and the can locking portion 7. It is preferable that the region 6c is made large and is made small near the center of the can body holding portion 5. At this time, the winding density (TA) of the area 6a near the opening side of the can body holding portion 5 and the winding density (TC) of the area near the can locking portion 7 are compared with the winding density (TB) near the center. The ratio (TA/TB, TC/TB) is preferably configured to be in the range of 1.2 to 2.0. When it is smaller than 1.2, the concentration of magnetic flux in the central portion of the heating coil 6 is not sufficiently relaxed, and an effect of preventing a problem due to excessive heat generation in the can body near the central portion of the heating coil 6 is prevented. Is small. On the other hand, when it is larger than 2.0, the heating of the central portion becomes insufficient and there is a possibility that the heating becomes non-uniform. Further, it is preferable that the winding density of the region 6c close to the can locking portion 7 be made higher than the winding density of the region 6a close to the opening side of the can body holding portion 5. With this structure, the lower side of the can is relatively strongly heated, so that convection of the content liquid occurs, the efficiency of heat transfer is increased, and the beverage inside is uniformly heated. The heating coil 6 having such a configuration is not limited to the can holding body 3 having the can locking portion 7, and the same effect can be obtained by applying the heating coil 6 to the conventional can holding body 3 having no can locking portion.

  At the lower end of the can body holding part 5, the can locking part 7 projects inward of the can body holding part 5 (in the direction of the center of the can body holding part 5), and the cap part 8 of the reseal can 2 passes through the center thereof. It is formed as an annular flat surface in which a hole 9 of the maximum size is formed. A cap holding portion 10 having a cylindrical inner surface with an inner diameter smaller than the inner diameter of the can body holding portion 5 is provided below it. The can body portion of the reseal can 2 inserted in the upright state is prevented from entering the cap holding portion 10 by the can locking portion 7, whereas the cap portion 8 of the reseal can 2 inserted in the upside down state is blocked. Passes through the can locking portion 7 and is held by the cap holding portion 10. The inner diameter and the depth of the cap holding portion 10 are set so as to hold the cap portion 8 of the reseal can 2 that is inserted in the inverted state. The heating coil 6 is not installed on the outer circumference thereof, and the heating coil 6 is installed on the outer circumference of the can body holding portion 5. That is, in a state in which the reseal can 2 is thrown into the can holder 3 so as to abut and is held, the heating coil 6 is provided on the outside of the side surface of the reseal can 2 excluding the cap portion 8 regardless of the throwing direction. It is arranged to be located only in. Therefore, the cap portion 8 of the reseal can 2 placed in the can holder 3 in the inverted state is not heated more than necessary.

  The can holder 3 is made of a material that can pass magnetic flux and has high heat resistance, such as polyacetal resin, polyether ether ketone resin, polycarbonate resin, MC nylon (registered trademark of Japan Polypenco Co., Ltd.) resin, or the like. Preferably. Moreover, it is preferable that the cap holding portion 10 is configured to shield the magnetic flux. With such a configuration, the magnetic flux reaching the threaded cap portion 8 held by the cap holding portion 10 is reduced, the generation of the induced current is suppressed, and unnecessary heating can be prevented. Specifically, the magnetic flux can be shielded by covering the cap holding portion 10 with ferrite or the like.

  A high frequency power supply device 11 that supplies a high frequency current to the heating coil 6 is provided below the motor 4. A part of the upper surface of the main body case 1 serves as a cover 12 that covers the opening of the can holder 3, and an operation panel (not shown) is installed beside it. The operation panel is provided with a start button for starting heating, a stop button for stopping the heating device on the way, a temperature adjusting button for adjusting the degree of heating, and the like.

  When the cover 12 is opened and the beverage can 2 is put into the can holder 3, the beverage can 2 put in the can holder 3 has its upper portion projected from the can holder 3 in order to facilitate the putting and taking out. It is retained in the state of being. After closing the cover 12 again, the operation panel is operated to start heating. In the present embodiment, for safety, a sensor (not shown) that detects the open/closed state of the cover 12 is installed, and the heating coil 6 is controlled so as not to be energized when the cover 12 is open.

  When the heating is started, the can holder 3 starts to rotate about the central axis A by the driving of the motor 4, and the high frequency power supply device 11 controlled by the control unit 13 supplies the high frequency current to the heating coil 6, The beverage can 2 is heated for a predetermined time and then automatically stopped. Since the beverage can 2 is induction-heated while rotating around the central axis A, the beverage can 2 is uniformly heated. In addition, since the contents are stirred together, efficient and uniform heating can be performed. In particular, in the case of the present embodiment, since the beverage can 2 is held and rotated in a state inclined at a predetermined angle with respect to the vertical line, the content liquid is in a turbulent state and the effect of stirring the content is high. It is possible to heat evenly in a shorter time. In this case, in order to enhance the stirring effect of the contents, the inclination angle with respect to the vertical line is preferably 10° or more and 80° or less, and more preferably 30° or more and 60° or less.

  FIG. 2 shows a case where the reseal can 2 is put in the can holder 3 of the present invention in a normal state. In the normal position, the can body portion of the reseal can 2 is locked by the can locking portion 7 and does not reach the cap holding portion 10. As a result, the can body is efficiently heated by the heating coil 6. The protrusion amount w of the can locking portion 7 in the present invention is preferably formed to be larger than the difference between the inner peripheral diameter Dh of the can barrel holding portion 5 and the outer peripheral diameter Dd of the can barrel. If the protruding amount w of the can locking portion 7 toward the inside of the can body holding portion 5 is smaller than the difference between the inner diameter Dh of the can body holding portion 5 and the can body outer diameter Dd, When the side surface is held in contact with the inner surface of the can body holding portion 5, there is a possibility that the other side surface of the can body portion does not come into contact with the can locking portion 7 and the holding of the can becomes unstable. is there. In particular, when the can is heated while being rotated or vibrated, it is necessary to hold the can stably, so it is effective to increase the protrusion amount w. When the protrusion amount w is formed to be larger than the difference between the inner peripheral diameter Dh of the can body holding portion 5 and the can body outer peripheral diameter Dd, even if one side surface of the can body portion is the inner surface of the can body holding portion 5. Even when held in contact with each other, the can body portion on the opposite side comes into contact with the can locking portion 7 to be reliably locked to the can locking portion 7, so that the can body portion is stable. It is held by the holding unit 5. In particular, when the diameter of the bottom of the can is reduced and the diameter of the contact portion is smaller than the outer diameter of the can body, as shown in FIG. 2, the radius of the contact portion (0.5 Ds) and the radius of the can body (0.5 Dd). It is more preferable that the amount of protrusion w be greater than the difference between the inner peripheral diameter Dh of the can body holding portion 5 and the contact length Ls. With this configuration, the ground contact portion is locked to the can locking portion 7, so that the can barrel portion is stably held by the can barrel holding portion 5. In the present embodiment, the inner diameter of the can body holding portion 5 is made larger than the outer diameter of the can body holding portion 5, and when the can body holding portion 5 is rotated, the retained reseal can 2 is retained. It is configured to roll on the inner surface of and to rotate freely. With this configuration, in addition to the effect of stirring the contents by the rotation of the beverage can 2, the inner diameter of the can body holding portion 5 is larger than the outer diameter of the can body. It is preferable because it can be taken out easily. In this case, the inner diameter of the can body holding portion 5 is preferably smaller than the height (length in the can axis direction) of the beverage can to be charged. When the inner diameter of the can body holding portion 5 is equal to or higher than the height of the beverage can, the contact area between the side surface of the beverage can and the inner surface of the can body holding portion 5 becomes small, so that the rotation of the beverage can easily becomes unstable, When the center axis of the beverage can rotates while tilting with respect to the center axis of the can body holding portion 5, the beverage can collides with the inner surface of the body holding portion 5 and scratches the outer surface of the beverage can, or during rotation. The central axis of the beverage can rotates with a large inclination with respect to the central axis of the can body holding portion 5, and the central axis of the beverage can is orthogonal to the central axis of the can body holding portion 5, that is, of the can body holding portion 5. When the beverage can is tilted with respect to the central axis direction, the side surface of the beverage can comes into contact with the can locking portion of the can body holding portion 5 and the beverage can is held, so that the heating of the beverage can is prevented. It is not preferable because it may be insufficient. In addition to this embodiment, the inner diameter of the can body holding portion 5 is made substantially the same as the outer diameter of the can body holding portion so that the reseal can 2 does not roll on the inner surface of the can body holding portion 5. It is also possible to rotate the can by holding the inner surface of the part 5 and the outer surface of the can body in close contact with each other. In this case, the inner surface of the can holder 5 is preferably covered with a heat-resistant elastic body such as rubber or sponge.

  FIG. 3 shows a case where the reseal can 2 is loaded in an inverted state. By forming the protrusion amount w of the can locking portion 7 in the present invention to be smaller than the difference between the outer radius (0.5 Dd) of the can body and the outer radius (0.5 Dc) of the cap 8, When the reseal can 2 is thrown in the inverted state, the cap portion 8 passes through the can locking portion 7 and is held below the can body holding portion 5, so that the screw cap portion 8 is unnecessarily used. It is never heated. Therefore, the resin coating or coating film on the inner surface of the cap portion 8 or the outer surface of the screw portion is thermally deteriorated or melted and damaged, or the frictional resistance between the outer surface of the screw portion and the inner surface of the cap portion 8 increases to make it difficult to open the cap. It is possible to avoid the occurrence of troubles such as discoloration or charring, which deteriorates the appearance and the taste or flavor of the contents.

  Moreover, since the cap portion 8 is held by the cap holding portion 10, the cap portion 8 is not heated more than necessary. Since the can body holding portion 5 holds the can body portion, the heating can be performed with substantially the same efficiency as in the normal state. When a plurality of types of reseal cans 2 having different can body diameters are heated by the induction heating device of the present invention, the inner diameter Dh of the can body holding portion 5 is equal to the outer diameter Dd of the can body. It is set to have a size capable of holding the largest can, and the protruding amount w of the can locking portion 7 is such that the smallest can of the outer diameter Dd of the can body does not pass through the can locking portion 7. In addition to the above setting, it is necessary to set so that the cap portions 8 of all types of reseal cans 2 to be inserted can pass through the can body holding portion 5.

  On the other hand, as shown in FIG. 7, when the resealing can 2 is held in the inverted state by the conventional can body holder 30 that is composed of only the so-called can body holding portion, the diameter reduction amount of the shoulder portion and the screw cap portion 8 is reduced. Is large and the diameter is reduced to a smaller diameter than the can body portion, the induced current that is generated is reduced due to the increased distance between the cap portion 8 and the heating coil 60, and the heating efficiency is greatly reduced. ..

  Further, as described above, the resin coating and the coating film on the inner surface of the cap portion 8 are melted and damaged by heating the cap portion 8 with the screw, and the outer surface of the screw portion of the mouth portion and the inner surface of the cap portion 8 are There is a possibility that problems may occur such as resin between the two being fused and making the cap difficult to open, discoloration or charring, resulting in a poor appearance, and a bad taste or flavor of the contents.

  In order to prevent the occurrence of such problems, the heating device is equipped with a sensor that detects the inverted state of the can, and when the can is thrown into the inverted state, the operator is notified to restore the normal state. It is also possible to do so. However, in this case, since the sensor has to be provided, the cost of the device increases, and when the device is thrown in the inverted state, the operator needs to reinsert the can, which causes a problem of poor operability. Further, when the reseal can 2 is thrown in an inverted state, the heating coil 60 is not installed at the height corresponding to the cap portion 8 from the bottom side of the can holder 30, but the heating coil 60 is installed above it. Therefore, it may be possible to heat only the can body of the reseal can 2 even in the inverted state. However, in this case, when the reseal can 2 is placed in the normal position or when a normal cylindrical can is heated, the area to be heated is narrowed, so that the heating becomes insufficient, There is a problem that the heating capacity is lowered, such as the time required for heating to a desired temperature becomes longer. In the present invention, such a problem does not occur, and even if the reseal can 2 is placed in an inverted state, it can be heated well.

  FIG. 5 shows an example of the mode of rotation of the can holder 3 in the induction heating device for beverage cans of the present invention, that is, the mode of rotation of the cans in the heating method of the present invention. In the present invention, while the can holder 3 or the can is being rotated, the number of revolutions thereof is repeatedly increased and decreased. To control the rotation of the can holder 3, the computer incorporated in the controller 13 is programmed in advance with the elapsed time from the start of operation and the rotational speed at the elapsed time, and the controller 13 controls the rotational speed of the motor 4. Can be controlled by controlling In FIG. 5, in the first rotation speed increasing section, the rotation speed is increased from the state in which the can holder 3 into which the beverage can 2 is placed to a stop to 800 rotations per minute for the first 1 second, and then the second rotation speed is increased. The rotation speed is maintained for a second. In the subsequent rotational speed reduction section, the rotational speed is reduced from 800 rpm to 400 rpm during the first 0.5 seconds, and the rotational speed is maintained for 1.5 seconds thereafter. Then, in the next rotation speed increasing section, the rotation speed is increased from 400 rotations per minute to 800 rotations per minute in the first 0.5 seconds, and the rotation speed is maintained for 1.5 seconds thereafter. Thereafter, in a similar manner, the rotation speed increasing section and the rotation speed decreasing section are alternately repeated every 2 seconds to perform heating for a predetermined time and stop heating. By increasing or decreasing the rotation speed in this way, the stirring effect of the contents can be enhanced, and the contents can be prevented from sticking to the inner surface of the beverage can 2. Moreover, since the heat generated in the can body is satisfactorily transferred to the contents, the heating efficiency is increased and the heating time can be shortened. Here, the length of the total rotation time from the start of rotation to the end of rotation, the length of time in the rotation speed increasing section and the rotation speed decreasing section, the rotation speed, etc. are determined by the type of beverage can 2 to be heated, the type of contents, It can be appropriately determined depending on the viscosity of the content, the mode of induction heating, and the like. Although not shown in FIG. 5, in this embodiment, after the can temperature reaches a desired temperature and the induction heating is stopped, the rotation speed increasing section and the rotation speed decreasing section are alternated for another 20 seconds. Repeat the above to stop the rotation of the can holder. As a result, the heat of the can body is well transferred to the contents and the temperature of the can surface is lowered, so that the heated beverage can is easily taken out.

  FIG. 6 shows an example of the pattern of induction heating in the present invention. In order to control the induction heating pattern, the computer built in the control unit 13 has elapsed time from the start of operation and how much output the high frequency current is supplied (energized) to the induction heating coil at the elapsed time. Alternatively, it can be performed by programming in advance whether to stop the supply of the high frequency current (interruption of energization) and controlling the high frequency power supply device 11 by the control unit 13. In the present embodiment, after 1 second has elapsed from the start of rotation of the can holder 3, the induction heating coil 6 is supplied with electric power to start induction heating, and induction is performed for 20 seconds at an output of 1.0 kW. Heating. After that, the power supply to the induction heating coil 6 is stopped, and after a non-heating section for 10 seconds, the power is supplied again to the induction heating coil 6 to perform induction heating at 1.0 kW for 10 seconds. After that, the non-heating section for 10 seconds and the heating section for 10 seconds are repeated after repeating. In this way, induction heating is intermittently performed for a predetermined time to heat the beverage can 2 to a desired temperature. By performing induction heating intermittently in this way, it is possible to prevent the occurrence of charring on the inner surface of the beverage can 2 even if the content having high viscosity and low fluidity is heated. Here, the induction heating is started after 1 second has elapsed from the start of rotation of the can holder 3 because the rotation of the beverage can 2 is unstable at the start of rotation, the rotation speed is insufficient, and the contents are sufficiently stirred. Since it is in a state where it is not heated, there is a risk that the contents will burn if it is heated in such a state, so after the specified time has elapsed from the start of rotation and the rotation of the beverage can has become stable It is necessary to do so. In addition, the induction heating time in the first heating section is longer than the heating time in the subsequent heating section, because the heating starts from the state where the beverage can is stored at a temperature equal to or lower than room temperature. This is because, even if the heating time is lengthened, the inner surface of the beverage can hardly sticks. In this way, by increasing the heating time in the first heating section, the temperature rise of the contents is promoted, so that the time from the operation start to the operation end of the beverage can induction heating device can be shortened. In the present embodiment, as described above, after the induction heating is stopped, the beverage can 2 is further rotated for 20 seconds to stop the rotation of the can holder 3. As a result, the heat of the can body is well transferred to the contents and the temperature of the can surface is lowered, so that the heated beverage can 2 can be easily taken out. The electric power supplied to the induction heating coil 6 and the length of time in the heating section and the non-heating section can be appropriately determined depending on the type of the beverage can 2 to be heated, the type and viscosity of the contents, and the like. In addition, when taking out the heated beverage can 2 after the heating is finished, the beverage can 2 is pushed up to the bottom of the can holder 3 except that the heated beverage can 2 is directly grasped by hand. It is also possible to project the tip of the beverage can 2 from the can holder 3 and take it out by grasping the projecting tip with a hand.

  As a first example of the present invention, the induction heating device for a beverage can having the can holder 3 of the above-described embodiment is used, and the resealing can 2 is heated in the normal state and the inverted state. Were compared.

  As the reseal can 2 to be heated, the outer diameter of the can body portion is about 52 mm, the diameter of the grounding portion is about 46 mm, the outer diameter of the cap portion 8 is about 38 mm, and the height of the can is about 124 mm. A filled steel reseal can 2 was used.

  As an example, a beverage can heating device having a cylindrical can holder 3 for holding a reseal can 2 having a can body holding portion 5, a can locking portion 7, and a cap holding portion 10 as shown in FIG. In, the inner diameter of the can body holding part 5 is 55 mm, the height of the can body holding part 5 (the height from the opening end to the can locking part 7) is 75 mm, the inner diameter of the cap holding part 10 is 42 mm, and the cap is When the height of the holding portion 10 (the height from the can locking portion 7 to the bottom portion) is 20 mm, when the reseal can 2 is held in the inverted state, the top surface of the cap portion 8 contacts the bottom surface of the cap holding portion 10. Configured to touch. Further, the can holder 3 is configured such that the central axis A of the held reseal can 2 is inclined at an angle of 45° with respect to the horizontal plane. In this embodiment, the can holder 3 is made of MC nylon (registered trademark of Japan Polypenco Co., Ltd.) resin.

  Regarding the protrusion amount w of the can locking portion 7, the difference between the inner diameter of the can body holding portion 5 and the outer diameter of the can body portion is 3 mm, and the inner diameter of the can body holding portion 5 and the ground contact length Ls. Is 6 mm, and the difference between the outer radius of the can body and the outer radius of the cap 8 is 7 mm, so it was set to 6.5 mm. A heating coil 6 is wound around the outer circumference of the can body holding portion 5, and is arranged so as to be installed on the outer circumference in a range from a position of 5 mm from the opening end to the can locking portion 7. As the heating coil 6, a litz wire formed by twisting two copper wires having a diameter of 0.12 mm was used. In the region near the opening side of the can body holding part 5 and the region near the can locking part 7, the number of windings of the litz wire is increased so that the density is closer to the center, In the vicinity, the number of windings was reduced so that the heating coil 6 was formed so as to be rough in the region near the opening side and the can locking portion 7 side.

  One side cross section of the heating coil 6 of the present embodiment is shown in FIGS. 4(a) and 4(b). In the present embodiment, the structure of the heating coil 6 is divided into three regions 6A, 6B and 6C on the opening side, the central part and the can locking part side so as to be different. First, in the opening side region 6A, the number of windings of the litz wire wound around the can body was set to 18 times. At this time, the distance in the central axis direction of the can of the opening side region 6A around which the litz wire is wound was 28 mm, and the winding density TA was 0.64 turns/mm. Further, in the opening side region 6A, the number of windings is 10 in the section 14 mm closer to the opening side and 8 in the section 14 mm closer to the center, and the number of windings and the winding density increase as the position approaches the center side. So formed. In the central region 6B, a predetermined gap is formed from the lower end of the opening-side region 6A, the number of windings is 6, the central region 6B has a distance of 12 mm in the can central axis direction, and the winding density TB is 0. 0.5 times/mm. Further, in the can locking portion side region 6C, a predetermined gap is provided from the lower end of the central portion side region 6B, the number of windings is 14, and the distance of the can locking portion side region 6C in the can central axis direction is 16 mm. The winding density TC was 0.88 turns/mm, and also in the can locking portion side region 6C, the number of windings was 6 times in the section of 8 mm near the center and 8 times in the section near the can locking section. As the number of windings and the winding density increase, the number of windings and the winding density increase toward the can locking portion side. The ratio (TA/TB) of the winding density of the opening side area 6A to the winding density of the central area 6B is about 1.3, and the winding density of the can locking portion side area 6C with respect to the winding density of the central area 6B. The ratio (TC/TB) was about 1.7. The winding density of the can locking portion side region 6C was set to be higher than that of the opening side region 6A, and the lower portion of the can was heated relatively strongly. An insulating layer 14 made of fluororesin (for example, Teflon (registered trademark of DuPont)) having a thickness of 1 mm was formed as an insulator between the can body holder 5 and the heating coil 6.

  Then, the high-frequency power supply device 11 generates a high-frequency controlled current of 20 kHz and supplies the current to the heating coil 6, and the induction of the beverage can that is induction-heated with the output of 2.5 kW while rotating the can holder 3 at 1000 rpm. The heating device was used to measure the rise of the can temperature when the resealed can 2 was in the upright position and the upside down condition.

  In addition, as a comparative example, an induction heating device for a beverage can having the same configuration as that of the example except that it has a can holder 30 only for the can body holder 5 without forming the can locking portion 7 and the cap holder 10 (see FIG. 7) was used to measure the rise of the can temperature when the reseal can 2 was in the upright state and the upside down state as in the example. Five cans were measured in each of the normal state and the inverted state, and the average value was obtained. The results are shown in Table 1.

  In the case of heating for 10 seconds from the can temperature of 25° C., the temperature rises by 26° C. from the temperature before heating and reaches 51° C. in any of the apparatus of Examples and Comparative Examples in the normal state. However, in the example, a temperature increase of 23.3° C. was obtained in the case of inversion, whereas in the comparative example, only a temperature increase of 15.5° C. was obtained in the case of inversion.

  In the comparative example, when held in the inverted state, a sufficient temperature increase cannot be obtained with respect to the normal state, whereas in the example, a current value and a temperature increase close to the normal state even in the inverted state are obtained. It can be heated to the extent that there is no practical problem.

  Although the embodiment and the first example of the present invention have been described above, the induction heating device for a beverage can of the present invention is not limited to the above-described embodiment and can be appropriately modified.

  For example, in the present embodiment, the central axis A of the reseal can 2 is held so as to be inclined at a predetermined angle with respect to the horizontal plane, but the central axis A is held so as to be perpendicular to the horizontal plane. It is also possible to In this case, of the beverage cans applied in the induction heating device for beverage cans, even when the beverage can having the smallest outer diameter is inserted, the can body portion surely abuts the can locking portion, and the beverage can is engaged. It is preferable to set the inner diameter of the can body holding portion 5 and the protruding amount of the can locking portion so that the can body holding portion 5 is stopped. This is because if the beverage can does not come into contact with the can locking portion and passes through the can locking portion and falls below the can, the heating efficiency decreases and the beverage can becomes difficult to take out.

  Further, in the present embodiment, the can locking portion 7 is formed as an annular plate having the hole 9 in the center, but it is formed as a protrusion protruding toward the inside (center side) of the can body holding portion 5. It is also possible. In this case, since the material of the can holder 3 can be saved, the cost of the device can be reduced. Further, in this case, in order to stably hold the can, it is preferable to provide three or more protrusions at equal intervals in the circumferential direction. Further, in the present embodiment, the protrusion amount w is configured to be constant over the entire area in the circumferential direction, but the protrusion amount w may be configured to be different in the circumferential direction.

  Further, the cap holding portion 10 may be formed with a taper portion whose inner diameter decreases toward the bottom side. By forming in this way, the resealing can 2 thrown in the inverted state does not come out and be damaged at the corner of the inner periphery of the can locking part 7, and the cap part 8 smoothly moves. Will be guided to.

  Further, in the present embodiment, when the reseal can 2 is inserted in the inverted state, the top surface of the cap portion 8 is held in contact with the bottom surface of the cap holding portion 10. It is also possible to make it hold|maintain by making it contact|abut to the stop part 7. In this case, it is preferable to provide a heat-resistant elastic body on the inner circumference of the can locking portion 7 that comes into contact with the shoulder of the resealing can 2. As a result, the can body can be held in a stable posture when the can is rotated and heated without causing damage to the can body due to the shoulder portion coming into contact with the can locking portion 7. Becomes

  In the case where the shoulder portion is configured to abut and hold the can locking portion 7, the cap holding portion 10 is not provided, and the cap portion 8 moves from the locking portion of the can holding body 3 to the outside on the bottom side. It can also be configured to project. In this case, since the cap holding portion 10 is not formed, the can holding body 3 can be easily manufactured, and the material cost can be reduced, so that the cost of the device can be reduced. In this case, since the drive shaft of the motor 4 cannot be joined to the bottom portion of the cap holding portion 10 to rotate in order to configure the can holding body 3 to rotate, the can holding body 3 is driven laterally. Appropriate means such as contacting a roller for rotation and rotating the roller can be used.

  Further, in the present embodiment, the can holder 3 holding the reseal can 2 is rotated and heated, but it is not always necessary to rotate, and heating conditions such as heating time and control of the heating coil 6 may be set. By properly setting, it is possible to heat the can holder 3 in a vibrating state or a stationary state. Further, although the present embodiment is directed to the steel can, the present invention is also applicable to an aluminum can. In the case of an aluminum can, the amount of heat generated by induction heating is smaller than that of a steel can and the heating efficiency is inferior. Therefore, it is preferable to use an appropriate means for increasing the heating capacity and the heating efficiency. Further, as the heating coil, a coil having a circular cross section in which a litz wire is wound outside the can body holding portion is used. However, the shape of the coil is not limited to the circular cross section, and a C-shaped cross section is used. It is possible to apply coils of various shapes, such as those having a circular or semicircular arc-shaped cross section.

  Next, as a second example, the heating states of the beverage cans were compared between the case where the heating pattern of the present invention and the rotation pattern of the can holder were used and the case where they were not used. As the reseal can 2 to be heated, as in the first embodiment, the outer diameter of the can body portion is about 52 mm, the diameter of the contact portion is about 46 mm, the outer diameter of the cap portion 8 is about 38 mm, and the height of the can is about 124 mm. A reseal can 2 made of steel filled with about 190 g of porridge as a content was used. Then, the beverage can induction heating device of the first embodiment was used to heat the beverage can according to the rotation pattern of the can body holding portion shown in FIG. 5 and the induction heating pattern shown in FIG. Specifically, the computer of the control unit 13 was programmed to control the motor 4 and the high frequency power supply device 11 as follows, and the induction heating device for the beverage can was operated. Regarding the rotation of the can body holding portion, first, the rotation of the motor 4 is started almost at the same time as the operation is started, and the rotation speed is increased to 800 rotations per minute after 1 second has elapsed from the start of the operation. Maintain the rotation speed of rotation. Then, in the subsequent 0.5 seconds, the rotation speed is reduced from the rotation speed of 800 rpm to the rotation speed of 400 rpm, and thereafter, the rotation speed of 400 rpm is maintained for 1.5 seconds. In the following 0.5 seconds, the rotation speed is increased from 400 rotations per minute to 800 rotations per minute, and the rotation speed is maintained at 800 rotations per minute for the following 1.5 seconds. After that, the rotation speed is reduced from 800 rotations per minute to 400 rotations per minute in 0.5 seconds, and then the rotation speed is maintained at 400 rotations per minute for 1.5 seconds. Rotation speed is increased and the rotation speed is increased from 400 rotations per minute to 800 rotations per minute in 0.5 seconds, and then the rotation speed is maintained at 800 rotations per minute for 1.5 seconds. The speed increasing section was alternately repeated every 2 seconds, and the rotation was controlled to stop 121 seconds after the start of the operation. Further, in the high frequency power supply device 11, the induction heating coil is energized 1 second after the operation of the beverage can induction heating device, that is, the rotation of the can holder is started, and induction heating is performed for 20 seconds. The induction heating coil is de-energized for 10 seconds thereafter, and the induction heating coil is energized again for induction heating for 10 seconds thereafter. After that, a non-heating section in which the induction heating coil is deenergized for 10 seconds and a heating section in which the induction heating coil is energized and induction heating is performed for 10 seconds are alternately repeated every 10 seconds. The heating section was controlled so as to end. The total heating section from the start of heating to the end of the last heating section is 60 seconds, the total of non-heating section is 40 seconds, the total rotation time from the start of rotation to the end of rotation is 121 seconds, and the end of the last heating section. For 20 seconds, the beverage can was rotated without induction heating, and then the rotation was stopped. The heating output was 1.0 kW, and a high frequency current of 20 kHz was generated and supplied to the heating coil 6. As a comparative example, induction heating was started 1 second after the start of rotation, and heating was continuously performed without passing through a non-heating section until the end of heating. With respect to the rotation of the can holder, after the rotation speed was increased to 800 rotations per minute from the start of rotation, the rotation speed was maintained until the end of heating. The total heating time from the start of heating to the end of heating was 60 seconds, the non-heating section was not provided, the total rotation time from the start of rotation to the end of rotation was 61 seconds, and the rotation was stopped immediately after the end of heating. The heating output was set to 1.0 kW as in the example, and a high frequency current of 20 kHz was generated and supplied to the heating coil 6. In each of the examples and the comparative examples, a sample of 10 cans was prepared, and the surface temperature of the beverage can was measured immediately after the rotation was stopped to confirm whether the inner surface of the beverage can was scorched.

  The average value of the surface temperature of the beverage can of the second example was 53.5° C., so that holding the beverage can with bare hands is not too hot, and can be easily taken out when taking out from the can holder. It was On the other hand, the average value of the surface temperature of the beverage can of the comparative example was 67.4° C., and it was too hot to hold the beverage can with bare hands, and the beverage can was taken out from the can holder with bare hands immediately after heating. It was difficult.

  Further, according to the second example, no charring of the inner surface of the beverage can occurred at all, whereas in the comparative example, all charring of the beverage can caused charring of the inner surface.

  Although the second embodiment has been described above, the induction heating device for a beverage can of the present invention is not limited to the above embodiment, and the length of time in the heating section and the non-heating section and the output of heating. The length of time and the number of rotations in the rotation speed increasing section and the rotation speed decreasing section can be appropriately changed according to the shape and material of the beverage can, the type of contents, and the like.

  INDUSTRIAL APPLICATION This invention can be utilized in the industrial field which manufactures and sells the apparatus which induction-heats the can filled with the content which is drunk or eaten in the warm state.

Claims (12)

A metal beverage can in which a screw portion is formed in a mouth portion having a diameter smaller than that of the can body portion, a cap portion is formed by winding a cap around the screw portion, and the cap portion is resealed. In an induction heating device for a beverage can, which has a can holder for holding, and an induction heating coil is arranged on the outer peripheral side of the can holder.
The can holder has an inner diameter equal to or larger than the outer diameter of the body of the beverage can, and has a can body holding portion having a predetermined height, and a can locking portion protruding inward of the can holding body,
The protruding amount of the can locking portion prevents the passage of the can body by contacting the bottom of the beverage can when the beverage can is thrown into the can holder from the bottom side in a normal state. And when the beverage can is thrown into the can holder in an inverted state from the mouth side, the amount of protrusion is set to pass the cap portion,
Whether the beverage can is held in either the upright state or the inverted state, the induction heating coil is arranged so as to be located only outside the side surface of the beverage can excluding the cap portion. An induction heating device for beverage cans, which is characterized by:   The induction heating device for a beverage can according to claim 1, wherein the protruding amount of the can locking portion is smaller than the difference between the outer radius of the can body and the outer radius of the cap. ..   The said induction heating coil is arrange|positioned only at the outer peripheral side of the said can body holding part in the said can holder, The induction heating apparatus of the beverage can of Claim 1 or 2 characterized by the above-mentioned.   The induction heating coil is wound so as to be rough at a central portion between the opening side and the can locking part side of the can body holding part, and between the opening side and the can locking part side. The induction heating device for a beverage can according to claim 1 or 2, characterized in that:   The induction heating coil is wound so as to be rough at a central portion between the opening side and the can locking part side of the can body holding part, and between the opening side and the can locking part side. The induction heating device for a beverage can according to claim 3, wherein:   The induction heating device for a beverage can according to claim 1 or 2, further comprising a rotating mechanism for rotating the beverage can held on the can holder around a central axis thereof. .. While rotating the beverage can by the rotating mechanism while holding the beverage can by the can holder, in the induction heating method of the beverage can induction heating the beverage can by the induction heating coil arranged on the outer peripheral side of the can holder,
While holding and rotating the beverage can in a state of being inclined at a predetermined angle with respect to the vertical line, from the start of rotation of the beverage can until the end of rotation, the rotation speed of the beverage can A method for induction heating a beverage can, comprising rotating the beverage can by alternately repeating an increase and a decrease in the rotation speed of the beverage can.   Start induction heating after starting the rotation of the beverage can, stop induction heating after heating the beverage can, after rotating the beverage can for a predetermined time in the state of not performing induction heating, the beverage can 8. The method for induction heating of a beverage can according to claim 7, wherein the rotation of is stopped.   The method of induction heating a beverage can according to claim 7 or 8, wherein the induction heating of the beverage can is intermittently performed.   The induction heating method for a beverage can according to claim 9, wherein the first induction heating time is longer than the subsequent induction heating times.   The induction heating method for a beverage can according to claim 9, wherein the induction heating coil is intermittently heated by energizing the induction heating coil every predetermined time and interrupting the energization.   The induction heating method for a beverage can according to claim 10, wherein the induction heating coil is intermittently heated by energizing the induction heating coil every predetermined time and interrupting the energization.

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