Heat Shrinkage Device

Abstract

To provide a heat-shrinking device for a heat-shrinkable film that can save energy.SOLUTION: A heat shrinking device (1) includes: a heating chamber (2) for heat shrinking a film covering a container (10); a conveyor (3) having a mounting surface (31a) for mounting the container (10) and conveying the container (10) within the heating chamber (2); a suction duct (42) for moving air in the heating chamber (2) out of the heating chamber (2) through an opening (31b) provided in the mounting surface (31a); and a return air supply (50) for returning the air moved from the heating chamber (2) back into the heating chamber (2).SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] The present invention relates to a heat shrinkage device for heating and shrinking a heat shrinkable film.

Background Art

[0002] A heat shrinkage device heats a heat shrinkable film with hot air or steam to shrink it and make it adhere to an article. When adhering the film to a light article such as an empty container, since the article may move from its fixed position due to the wind speed of the hot air or the pressure of the steam, measures are required to prevent the article from moving. Conventionally, for example, the technology disclosed in Patent Document 1 has been used. Patent Document 1 discloses a technique of attracting air from below the conveyor to attract an article to the conveyor. As a result, since the article is fixed to the conveyor, even if hot air or steam hits the article, it is possible to prevent the article from moving. In Patent Document 1, the sucked air is discharged to the outside of the building.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, when using the above-described conventional technology in a heat shrinkage device, air is sucked from below the conveyor in a heating chamber where hot air or steam is applied to the article to fix the article to the conveyor. In that case, the heat in the heating chamber is sucked together with the air in the heating chamber, and the heat in the heating chamber is also discharged to the outside of the building together with the sucked air. Therefore, the temperature in the heating chamber drops, and it becomes impossible to ensure the temperature required for the film to adhere to the article by heat shrinkage. For this reason, it is necessary to control the temperature in the heating chamber to be higher, which poses a problem from the viewpoint of energy saving.

[0005] One aspect of the present invention has been made in view of the above-described conventional problems, and an object thereof is to provide a heat shrinkage device for a heat shrinkable film capable of achieving energy saving.

Means for Solving the Problems

[0006] In order to solve the above problems, a heat shrinkage device according to one aspect of the present invention includes a heating chamber that heats and shrinks a heat shrinkable film that covers an article, a placement surface for placing the article, and a conveyance unit for conveying the article in the heating chamber, an internal air movement unit for moving the air in the heating chamber to the outside of the heating chamber through an opening provided in the placement surface, and an internal air return unit for returning the air moved from the heating chamber to the outside of the heating chamber back into the heating chamber.

[0007] According to the above configuration, the air moved from the heating chamber to the outside of the heating chamber by the internal air movement unit is returned to the heating chamber by the internal air return unit. Thereby, the heat of the heating chamber that has been moved together with the air in the heating chamber is also returned to the heating chamber by the internal air return unit and can be used for the film to adhere to the article by heat shrinkage, so that energy saving can be realized.

[0008] The heat shrinkage device may include a first blowing unit that blows high-temperature air onto the article, and a second blowing unit that blows the air moved from the heating chamber to the outside of the heating chamber onto the article whose film has been heated and shrunk by the first blowing unit.

[0009] According to the above configuration, the air moved from the heating chamber to the outside of the heating chamber can be blown onto the article whose heat shrinkable film has been heated and shrunk. Thereby, the heat shrinkable film can be pre-shrunk, and the finish of the film adhering to the article by heat shrinkage can be assisted. Further, since the blowing of the air moved from the heating chamber to the outside of the heating chamber onto the article is performed near the outlet of the heating chamber, the blowing serves as an air curtain and can prevent hot air from exiting the heating chamber.

[0010] In the above-described heat shrinkage device, the heating chamber has an inlet for the article conveyed by the conveying unit to enter the heating chamber and an outlet for the article conveyed through the heating chamber by the conveying unit to exit the heating chamber. The internal air return unit may return the air moved from inside the heating chamber to outside the heating chamber to at least one of the upper parts of the inlet and the outlet.

[0011] According to the above configuration, since the air moved from inside the heating chamber to outside the heating chamber flows from at least one of the upper parts of the inlet and the outlet to the lower part, it is possible to prevent hot air from coming out from the inlet or the outlet of the conveying unit in the heating chamber. Thereby, heat can be retained in the heating chamber, so that the heat utilization efficiency of the heating chamber can be improved.

[0012] In the above-described heat shrinkage device, the internal air return unit may return the air moved from inside the heating chamber to outside the heating chamber to the upper part of the heating chamber.

[0013] According to the above configuration, by returning the air moved from inside the heating chamber to outside the heating chamber to the upper part of the heating chamber, the high-temperature air staying in the upper part of the heating chamber can be moved to the lower part of the heating chamber by the air moved from inside the heating chamber to outside the heating chamber. Thereby, the temperature inside the heating chamber can be stabilized.

[0014] In the above-described heat shrinkage device, the heating chamber includes a blowing unit that surrounds the article conveyed through the heating chamber by the conveying unit and blows high-temperature air, a circulation blower that is provided at the upper part of the heating chamber, sucks the air in the heating space surrounded by the blowing unit to outside the heating space, and circulates the air inside and outside the heating space by sending the sucked air into the heating space, and a heating member that heats the air circulated by the circulation blower. The internal air return unit may return the air moved from inside the heating chamber to outside the heating chamber from the upper part of the heating chamber to outside the heating space.

[0015] According to the above configuration, by means of the circulation blower, the air in the heating chamber is sucked up from the heating space surrounding the article to the outside of the heating space and circulated along a circulation path that sends it from outside the heating space into the heating space. Further, the circulated air in the heating chamber is heated by the heating member on the above-mentioned circulation path. By means of the internal air return part, the air moved from the inside of the heating chamber to the outside of the heating chamber is returned from the upper part of the heating chamber to the outside of the heating space, so that the air moved from the inside of the heating chamber to the outside of the heating chamber can be returned to the circulation path of the air in the heating chamber by the circulation blower. Thereby, the circulation efficiency of the air in the heating chamber can be improved.

Effect of the Invention

[0016] According to one aspect of the present invention, it is possible to provide a heating and shrinking device for a heat-shrinkable film that can achieve energy savings.

Brief Description of the Drawings

[0017]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Modes for Carrying Out the Invention

[0018] 〔Embodiment〕 Hereinafter, an embodiment of the present invention will be described in detail with reference to FIGS. 1 to 6. In the following, the side of the conveyor 3 of the heating and shrinking device 1 will be described as the lower part, and the side of the circulation blower 12 will be described as the upper part.

[0019] [Outline of Heating and Shrinking Device] FIG. 1 is a partial cross-sectional view showing the configuration of a heat shrinkage device 1 according to an embodiment of the present invention. In FIG. 1, the lower side of the broken line D shows the cross-section of the heat shrinkage device 1. The heat shrinkage device 1 is a device that heats and shrinks a label 101 (film) made of a heat-shrinkable material by applying steam or hot air to a container 10 (article) covered with the label 101, and adheres the label 101 to the container 10. As shown in FIG. 1, the heat shrinkage device 1 includes a heating chamber 2, a conveyor 3 (transport unit), and a circulation unit 40 (see FIG. 3).

[0020] The conveyor 3 transports the container 10 covered with the heat-shrinkable label 101 in a predetermined direction. The conveyor 3 is composed of, for example, a belt conveyor, and has a conveyor belt 31, a drive shaft 32, a conveyor motor 33 (see FIG. 3), and a driven shaft 34. The conveyor belt 31 is formed in a ring shape, and the drive shaft 32 and the driven shaft 34 arranged substantially parallel are disposed at both ends on the inner surface of the conveyor belt 31. In other words, the conveyor belt 31 is wound around the drive shaft 32 and the driven shaft 34. Thereby, a space 35 is formed on the inner surface side of the conveyor belt 31. The conveyor motor 33 is connected to the drive shaft 32. The rotation of the conveyor motor 33 is transmitted to the drive shaft 32, and the conveyor belt 31 moves as the conveyor motor 33 rotates. The driven shaft 34 rotates as the conveyor belt 31 rotates.

[0021] The conveyor belt 31 has a placement surface 31a on which the container 10 is placed. A plurality of openings 31b are formed at a predetermined interval on the placement surface 31a. The openings 31b are formed so as to penetrate between the placement surface 31a and the inner surface of the conveyor belt 31. The conveyor 3 moves the heating chamber 2 with the container 10 placed on the placement surface 31a so as to block the openings 31b. In the space 35 on the inner surface side of the conveyor belt 31, a suction duct 42 of the circulation unit 40 (see FIG. 3) is arranged at the same interval as the openings 31b.

[0022] The circulation unit 40 (see FIG. 3) sucks the air in the heating chamber 2 out of the heating chamber 2 from below the opening 31b, and circulates the air so as to return the sucked air (the air moved from the heating chamber 2) from the heating chamber 2 back into the heating chamber 2. As shown in FIG. 1, the suction duct 42 is provided as a pipe for sucking the air in the heating chamber 2. The suction duct 42 extends from the lower part to the upper part of the space 35 up to the vicinity of the inner surface of the conveyor belt 31 located at the upper part, and the upper end 42a which is one end of the suction duct 42 is opened in the vicinity of the inner surface of the conveyor belt 31 located at the upper part. The other end of the suction duct 42 is connected to a suction blower 41 (see FIG. 3).

[0023] In the heating chamber 2, when the label 101 is adhered to the container 10, hot air or steam is applied toward the label 101. At this time, if the container 10 is not fixed to the conveyor belt 31, the container 10 may move from its fixed position due to the wind speed of the hot air or the pressure of the steam, and the hot air or steam may not hit the desired location of the container 10. Therefore, in the heat shrinkage device 1, the container 10 is fixed to the conveyor 3 using the circulation unit 40. Specifically, the moving conveyor belt 31 stops when the position of the opening 31b and the position of the opening of the upper end 42a of the suction duct 42 substantially coincide. Then, when heating starts in the heating chamber 2, the suction blower 41 sucks the air in the heating chamber 2 through the suction duct 42 from below the opening 31b. As a result, the space below the bottom surface of the container 10 becomes a negative pressure state, and the container 10 placed on the opening 31b is fixed to the conveyor 3. The circulation unit 40 will be described in detail later.

[0024] The container 10 is, for example, a PET bottle made of polyester formed by blow molding. However, the object to be coated with the label 101 is not limited to the container 10, and any article around which the label 101 is wound and used may be used.

[0025] The label 101 is formed of a heat-shrinkable film (shrink film) made of polyethylene, polypropylene, PVC, etc. The label 101 is formed into a cylindrical shape by joining both ends thereof, and then wound into a roll shape. While feeding out this roll, it is cut to a predetermined length. The label 101 is opened into a cylindrical shape by an opening device (not shown) and is mounted so as to cover the container 10.

[0026] The heating chamber 2 forms a space for heating the label 101 that covers the container 10 conveyed by the conveyor 3. The heating chamber 2 heats and shrinks the label 101 that covers the container 10 to make it adhere closely to the container 10. The temperature for heating and shrinking the label 101 is, for example, 160°C or higher and 220°C or lower.

[0027] [Details of the Heating Chamber] Subsequently, the internal structure of the heating chamber 2 will be described based on FIGS. 1 and 2. FIG. 2 is a cross-sectional view taken along the line A-A of FIG. 1, and is a longitudinal sectional view showing the internal structure of the heating chamber 2 of the heat-shrinking device 1. As shown in FIG. 2, the heating chamber 2 has an outer casing 11, a circulation blower 12, a heater 13 (heating member), and an air guiding portion 14.

[0028] The outer casing 11 forms the outer shell of the heating chamber 2. The outer casing 11 has an upper surface wall 11a and side walls 11b extending downward from both side ends of the upper surface wall 11a, and the lower end is open. The heating chamber 2 is covered by the conveyor 3. In the outer casing 11, an inlet 21 for the container 10 conveyed by the conveyor 3 to enter the heating chamber 2 and an outlet 22 for the container 10 conveyed through the heating chamber 2 by the conveyor 3 to exit the heating chamber 2 are formed.

[0029] The circulation blower 12 is provided above the heating chamber 2, sucks up the air in the heating chamber 2, and blows it out laterally to circulate the air heated by the heater 13 within the heating chamber 2. In other words, the circulation blower 12 sucks up the air within the heating zone 19 surrounded by the nozzle wall 17 (to be described later) up to outside the heating zone 19, blows out the sucked-up air outward from the heating zone 19, and feeds it into the heating zone 19, thereby circulating the air inside and outside the heating zone 19. The circulation blower 12 has a blower motor 12a, blades 12b, and a casing 12c. The blower motor 12a is attached on the upper surface wall 11a of the outer housing 11. The blades 12b rotate via the drive shaft of the blower motor 12a. The blades 12b are provided inside the casing 12c disposed near the inner surface of the upper surface wall 11a of the outer housing 11. The air sucked up from below the casing 12c by the rotation of the blades 12b is blown out in the diametrical direction of the blades 12b from the air outlet of the casing 12c provided on the side of the blades 12b.

[0030] The heater 13 is a heating element such as a sheathed heater and forms a circle. The heater 13 is attached to the inner surface of the upper surface wall 11a of the outer housing 11 so as to be disposed around the casing 12c. The heater 13 heats the air blown out from the air outlet of the casing 12c. In other words, the heater 13 is attached laterally to the circulation blower 12 and heats the air circulating within the heating chamber 2 blown out laterally by the circulation blower 12.

[0031] The air guiding part 14 has a fixed wall 16 and two nozzle walls 17 (the first spraying part).

[0032] The fixed wall 16 has an upper surface portion and side surface portions that extend downward from both side ends of the upper surface portion, and the lower end is open. The upper surface portion is connected to the casing 12c and has a through hole that communicates the casing 12c and the air guiding portion 14. The position of the lower end of the side surface portion is the same as the position of the lower end of the side wall 11b of the outer casing 11. Also, the fixed wall 16 is formed smaller than the outer casing 11 and is disposed at a position such that the outer surface of the side surface portion of the fixed wall 16 has a predetermined interval from the inner surface of the side wall 11b of the outer casing 11. Thereby, a circulation space 18 is formed between the inner surface of the side wall 11b of the outer casing 11 and the outer surface of the side surface portion of the fixed wall 16.

[0033] The nozzle wall 17 is fitted so as to face the two side surface portions of the fixed wall 16. The nozzle wall 17 has a number of nozzle holes 17a. The nozzle holes 17a are arranged in a matrix and are formed so as to penetrate the nozzle wall 17 in the horizontal direction. The nozzle wall 17 blows high-temperature air onto the container 10 through the nozzle holes 17a. The container 10 passes through a heating zone 19 (heating space) which is a space formed between the opposing nozzle walls 17. In other words, the nozzle wall 17 surrounds the container 10 conveyed in the heating chamber 2 by the conveyor 3 and blows high-temperature air onto the container 10. Note that the shape of the nozzle holes 17a is not limited to the shape in FIG. 2 and can be set as appropriate.

[0034] [Air Circulation in the Heating Chamber] In the heating chamber 2 configured as described above, the air in the heating zone 19 within the fixed wall 16 is sucked up by the circulation blower 12, blown out to the side of the heater 13 by the blades 12b, and heated by the heater 13. The heated air passes through the circulation space 18, is blown out from each nozzle hole 17a of the nozzle wall 17 into the heating zone 19, then heats the label 101 covering the container 10 and is sucked up again by the circulation blower 12.

[0035] In this way, the circulation blower 12 generates an air flow that circulates the air heated by the heater 13 inside the heating chamber 2. Thereby, in the heating chamber 2, the heated air circulates.

[0036] The heat shrinkage device 1 is provided with a control unit (not shown). The control unit controls the heat generation temperature of the heater 13 so that the temperature of the air detected by a temperature sensor (not shown) disposed in the circulation space 18 becomes a predetermined temperature.

[0037] Note that the nozzle wall 17 may be provided such that the nozzle hole 17a can be opened and closed. Thereby, hot air can be blown out to a desired location of the container 10.

[0038] [Circulation section] The circulation section 40 will be described with reference to FIGS. 1 to 5. FIG. 3 is a schematic diagram showing a schematic configuration of the circulation section 40 in the heat shrinkage device 1. The two-dot chain line in FIG. 3 is a virtual line and shows the heating chamber 2. FIG. 4 is a partial cross-sectional view taken along the line B-B of FIG. 3 and is a path diagram of the suction side of the circulation section 40 of the heat shrinkage device 1. FIG. 5 is another partial cross-sectional view taken along the line B-B of FIG. 3 and is a path diagram of the discharge side of the circulation section 40 of the heat shrinkage device 1. Note that, for the return air duct 43 in FIG. 5, a side view of the heating chamber 2 as seen from the side of the conveyor motor 33 is shown.

[0039] As shown in FIGS. 1 and 3 to 5, the circulation section 40 sucks the air in the heating chamber 2 out of the heating chamber 2 from the opening 31b. Further, the circulation section 40 blows the sucked air onto the container 10 with the label 101 heat-shrunk via the return air supply section 50. This will be described in detail below.

[0040] As shown in FIG. 3, the circulation section 40 includes a suction blower 41 (inner air moving section, inner air returning section), a suction duct 42 (inner air moving section), a return air duct 43 (inner air returning section), and a return air supply section 50 (inner air returning section). The suction blower 41 sucks air from the suction port and discharges the sucked air from the discharge port.

[0041] (Suction side of the circulation section (inner air moving section)) The suction side of the circulation unit 40 moves the air in the heating chamber 2 outside the heating chamber 2 through the opening 31b provided on the placement surface 31a. As shown in FIGS. 1, 3, and 4, the circulation unit 40 has a suction duct 42 on the suction side of the suction blower 41. One end of the suction duct 42 is connected to the suction port of the suction blower 41, and the other end of the suction duct 42 extends from the lower part to the upper part in the space 35 inside the conveyor 3 and is opened near the inner surface of the conveyor belt 31 located at the upper part. The suction ducts 42 are set up at the same intervals as the intervals at which the respective openings 31b are arranged, and the respective suction ducts 42 branched so as to be set up in the space 35 merge and are connected to the suction blower 41.

[0042] When heating starts in the heating chamber 2, the suction blower 41 starts suction, and the suction blower 41 suctions the heated air in the heating chamber 2 from below the opening 31b. As a result, as shown by the arrows in FIGS. 3 and 4, the heated air in the heating chamber 2 is suctioned outside the heating chamber 2. The suction force by the suction blower 41 can be set manually and can be changed according to the container 10. After setting the suction force, the suction blower 41 is driven with a constant suction force, and the suction force is not changed during the operation of the heat shrinkage device 1. In addition, in the present embodiment, the air in the heating chamber 2 is suctioned by the suction blower 41 and moved outside the heating chamber 2, but the method of moving the air in the heating chamber 2 outside the heating chamber 2 is not limited to the above, and any method may be used as long as the air in the heating chamber 2 can be moved outside the heating chamber 2.

[0043] (Discharge side of the circulation unit (internal air return unit)) The discharge side of the circulation unit 40 returns the air that has been moved from inside the heating chamber 2 to outside the heating chamber 2 back into the heating chamber 2. As shown in FIGS. 1, 3, and 5, the circulation unit 40 has a return air duct 43 and a return air supply unit 50 on the discharge side of the suction blower 41. One end of the return air duct 43 is connected to the discharge port of the suction duct 42, and the other end is connected to the return air supply unit 50.

[0044] The air return supply unit 50 is a substantially rectangular parallelepiped box. There are a pair of air return supply units 50, and the pair of air return supply units 50 are installed on both sides near the outlet of the heating chamber 2, and the conveyor belt 31 passes between the air return supply units 50. That is, between the air return supply units 50 arranged on both sides of the heat shrinkage device 1, the container 10 with the label 101 adhered by heat shrinkage passes through. The air return supply unit 50 has an air return nozzle wall 51 (second spraying unit) that sprays suction air onto the container 10 with the label 101 heat-shrunk in the heating chamber 2. Specifically, the air return nozzle wall 51 is formed on the side surface of the air return supply unit 50 through which the conveyor belt 31 passes. The air return nozzle wall 51 has a large number of air return nozzle holes 50a. The air return nozzle holes 50a are arranged in a matrix and are formed so as to penetrate the air return nozzle wall 51 of the air return supply unit 50 in the horizontal direction. Note that the shape of the air return nozzle holes 50a is not limited to the shape in FIG. 5 and can be set as appropriate.

[0045] The suction air sucked by the suction blower 41 passes through the air return duct 43 as shown by the arrow in FIG. 5, and is sprayed through the air return nozzle holes 50a via the air return supply unit 50 onto the container 10 with the label 101 adhered by heat shrinkage. By further spraying the suction air onto the container 10, the label 101 can be pre-shrunk, and the finish of the heat shrinkage of the label 101 can be assisted. The air sprayed onto the container 10 is circulated again in the heating chamber 2 by the air circulation in the heating chamber 2 described above.

[0046] Here, since the suction blower 41 is outside the heating chamber 2, the air sucked from the heating chamber 2 will come out of the heating chamber 2 once, but since the time is extremely short, the temperature of the air hardly drops. Therefore, compared with taking in new air from the outside and circulating it in the heating chamber 2, the time for the circulating air in the heating chamber 2 to rise in temperature is shortened, and the thermal efficiency of the heat shrinkage device 1 is improved.

[0047] It is desirable that the wind speed of the air sprayed from the air return nozzle holes 50a onto the container 10 is fast. Thereby, it is possible to prevent the heat of the heating chamber 2 from leaking to the outside from the outlet of the heating chamber 2. Note that even if the wind speed is slow, it does not affect the shrinkage of the label 101.

[0048] [Effect] FIG. 6 is a schematic diagram showing a schematic configuration of a heat shrinkage device 100 which is an example of a conventional heat shrinkage device. The two-dot chain line in FIG. 6 is a virtual line and shows the heating chamber 2. As shown in FIG. 6, in the conventional heat shrinkage device 100, the heated air in the heating chamber 2 sucked from the opening 31b of the conveyor belt 31 was exhausted into the room where the heat shrinkage device 100 was installed. Therefore, the indoor environment of the room where the heat shrinkage device 100 was installed was affected, such as fluctuations in the temperature and humidity of the room where the heat shrinkage device 100 was installed and the air pressure in the room. In order to solve such a problem, the sucked air may be discharged to the outside of the building as in the technique disclosed in Patent Document 1 described above, but there is another problem that requires an exhaust structure to the outside of the building.

[0049] Further, in the heat shrinkage device 100 and the heat shrinkage device adopting the technique of Patent Document 1, the heat in the heating chamber 2 is also discharged outside the heating chamber 2 together with the air in the heating chamber 2. Therefore, the temperature in the heating chamber 2 drops, and it becomes impossible to secure the temperature necessary for the finish of heat shrinkage for closely adhering the label 101 to the container 10. In such a state, since the detected temperature of the temperature sensor provided in the circulation space 18 decreases, the control unit has to increase the heat generation temperature of the heater 13 in order to secure the temperature in the heating chamber 2 necessary for the finish of the close adhesion of the label 101 to the container 10 by heat shrinkage. For example, it was necessary to increase the heat generation temperature (finish temperature) of the heater 13 to about 250°C.

[0050] In contrast, in this embodiment, since the heat of the heating chamber 2 sucked together with the air in the heating chamber 2 is returned to the heating chamber 2 by the circulation unit 40, energy savings can be achieved compared to the conventional case of introducing new air from the outside into the heating chamber 2. Specifically, in the above conventional case, the finishing temperature required for the label 101 to adhere to the container 10 was about 150°C, whereas according to the present invention, the above finishing temperature can be lowered to about 125°C. That is, about 17% energy savings can be achieved with respect to the finishing temperature. Also, in the above conventional case, the wind speed of the air blown onto the container 10 through the nozzle hole 17a was about 55 m / s, whereas according to the present invention, the above wind speed can be lowered to about 45 m / s. That is, about 18% energy savings can be achieved with respect to the wind speed. Furthermore, since the sucked heat of the heating chamber 2 can be reused, waste heat can be reduced.

[0051] Also, since the sucked air in the heating chamber 2 is blown out near the outlet 22 of the heating chamber 2, it is possible to prevent the heat of the heating chamber 2 from leaking to the outside from the outlet 22 of the heating chamber 2.

[0052] Also, according to such a configuration, waste heat can be reduced and the finishing temperature required for the film to adhere to the article due to heat shrinkage can be lowered. Thereby, it can contribute to the achievement of Goal 7, "Ensure access to affordable, reliable, sustainable and modern energy for all" of the Sustainable Development Goals (SDGs).

[0053] [Modification Example] The modification example of the present invention will be described below. For the sake of convenience of explanation, members having the same functions as the members described in the above embodiment are denoted by the same reference numerals, and the description thereof will not be repeated.

[0054] In the above embodiment, the heated air in the heating chamber 2 sucked by the suction blower 41 was blown onto the container 10 by the return air supply unit 50, but it is not limited to the above. The circulation unit 40 may return the heated air in the heating chamber 2 sucked by the suction blower 41 to, for example, at least one of the upper parts of the inlet 21 and the outlet 22 in the heating chamber 2 shown in FIG. 1. Thereby, it is possible to prevent the heat of the heating chamber 2 from leaking to the outside from at least one of the inlet 21 and the outlet 22 of the heating chamber 2.

[0055] Furthermore, the circulation unit 40 may return the heated air in the heating chamber 2 sucked by the suction blower 41 into the heating chamber 2 from above the heating chamber 2. Specifically, as shown in FIG. 2, an air outlet 60 is arranged above the heating zone 19, and the circulation unit 40 may blow out the sucked air from the air outlet 60 toward the lower part of the heating zone 19. As a tendency, heat tends to accumulate in the upper part of the heating zone 19, and the heat in the lower part of the heating zone 19 becomes lower. Therefore, by blowing out the sucked air from the air outlet 60 arranged above the heating zone 19 toward the lower part of the heating zone 19, the heat accumulated in the upper part of the heating zone 19 can be sent to the lower part of the heating zone 19. Thereby, the heat in the heating zone 19 can be made uniform, and the finish of the label 101 can be made uniform.

[0056] Also, the heated air in the heating chamber 2 sucked by the suction blower 41 may be returned from above the heating chamber 2 into the heating chamber 2 and outside the heating zone 19. Specifically, as shown in FIG. 2, an air outlet 70 is formed in the upper surface wall 11a of the outer body 11, and the circulation unit 40 may blow out the sucked air from the air outlet 70 toward the lower part of the heating chamber 2. In this way, by returning the sucked air onto the circulation path of the air in the heating chamber 2 by the circulation blower 12, the circulation efficiency of the air in the heating chamber 2 can be improved. Also, although not shown, an air outlet may be formed in the upper part of the side wall 11b of the outer body 11. This air outlet is formed to have a downward slope from the outer surface to the inner surface of the side wall 11b. The circulation unit 40 may blow out the sucked air into the heating chamber 2 obliquely downward from such an air outlet.

[0057] Further, the circulation unit 40 may supply the suction air to a space other than the heating chamber 2 for heating the label 101, for example, a preheating chamber, in the same manner as the heating chamber 2. The preheating chamber heats the label 101 at a temperature lower than that of the heating chamber 2 so as to shrink the label 101 to some extent before the heating by the heating chamber 2. The air in the heating chamber 2 sucked by the circulation unit 40 is supplied to the preheating chamber through a duct connected between the heating chamber 2 and the preheating chamber. When the temperature of the suction air supplied to the preheating chamber decreases due to the influence of the outside air temperature while passing through the duct, the suction air is heated to an appropriate temperature by a heater in the preheating chamber. Thus, by supplying the air sucked from the heating chamber 2 to the preheating chamber, the thermal efficiency in the preheating chamber can be improved.

[0058] Also, the circulation unit 40 may return the suction air to the circulation space 18. Specifically, for example, as shown in FIG. 5, the wall surface on the nozzle wall 17 side of the return air supply unit 50 is provided with holes 50b from the upper part to the lower part, and the suction air may be returned to the circulation space 18 side through the holes 50b. Thereby, the opening area in the return air supply unit 50 becomes larger, and the suction force of the air in the heating chamber 2 of the circulation unit 40 can be increased. Further, the effect of preventing the hot air from coming out from the outlet 22 of the heating chamber 2 through the hole 50a can be further enhanced. Furthermore, as shown in FIG. 5, the upper surface of the return air supply unit 50 is provided with holes 50c, and the suction air may be returned to the circulation space 18 through the holes 50c. Thereby, the suction air can be returned to a location close to the circulation blower 12.

[0059] 〔Supplementary Notes〕 The present invention is not limited to the above-described embodiments, and various modifications are possible within the scope shown in the claims. The configurations obtained by appropriately combining the technical means disclosed in the embodiments are also included in the technical scope of the present invention.

Explanation of Reference Numerals

[0060] 1 Heating and Shrinking Device 2 Heating Chamber 3 Conveyor (Transport Unit) 10 Container (Article) 12 Circulation Blower 13 Heater (Heating Member) 17 Nozzle wall (first spraying part, spraying part) 19 Heating zone (heating space) 21 Inlet 22 Outlet 31a Placing surface 31b Opening 41 Suction blower (inner air moving part, inner air returning part) 42 Suction duct (inner air moving part) 43 Return air duct (inner air returning part) 50 Return air supply part (inner air returning part) 51 Return air nozzle wall (second spraying part) 101 Label (film)

Claims

1. A heating and shrinking device comprising: a heating chamber that heats and shrinks a tubular label made of a heat-shrinkable film covering an article by blowing hot air from a nozzle wall on the side of the article; a placement surface for placing the article thereon, and a transport unit for transporting the article in the heating chamber; an internal air movement unit that fixes the article to the placement surface at its bottom surface by sucking air from an opening provided in the placement surface, and moves the air in the heating chamber to the outside of the heating chamber; an internal air return unit that returns the air moved from the inside of the heating chamber to the outside of the heating chamber back into the heating chamber.

2. a first blowing unit that blows hot air onto the article; a second blowing unit that blows the air moved from the inside of the heating chamber to the outside of the heating chamber onto the article from the side of the article, the film of which has been heated and shrunk by the first blowing unit, the heating and shrinking device according to claim 1.

3. The heating chamber surrounds the article transported in the heating chamber by the transport unit and includes a blowing unit that blows hot air, a heating space is formed by being surrounded by the blowing unit, The heating chamber further includes: a circulation blower provided at the upper part of the heating chamber, which sucks the air in the heating space to the outside of the heating space and circulates the air in the heating chamber and sends it into the heating space, thereby circulating the air inside and outside the heating space; a heating member that heats the air circulated by the circulation blower, the heating and shrinking device according to claim 1, wherein the internal air return unit returns the air moved from the inside of the heating chamber to the outside of the heating chamber back to the outside of the heating space of the heating chamber.

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