Shrinking apparatus and method

Abstract

Fill the space into which steam is supplied for the heat shrinkage of the shrink film with as much steam as possible. [Solution] The disclosed shrink wrapping device heats and shrinks a shrink film and attaches it to an object being conveyed in the conveying direction. The shrink wrapping device comprises a first heating chamber to which steam is supplied for heating and shrinking the shrink film; an exhaust chamber provided on at least one side of the first heating chamber, on the upstream and downstream sides in the conveying direction; and a steam supply device configured to supply steam to the first heating chamber and to resupply at least a portion of the steam that has flowed out of the first heating chamber to the exhaust chamber back to the first heating chamber.

Description

Technical Field

[0001] The present disclosure relates to a shrinking device and method.

Background Art

[0002] Patent Document 1 discloses a processing device that heats and shrinks a film having heat shrinkability with steam.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

[0004] When heating and shrinking a film (shrink film) with steam, in order to improve the finished quality of the shrink film after heating and shrinking, it is preferable to fill the space where steam is supplied for heating and shrinking the shrink film with steam as much as possible.

[0005] However, there is a possibility that a gas (dry air) containing almost no steam may flow into the space where steam is supplied from the upstream side or the downstream side in the conveyance direction of the target product. The inflow of dry air deteriorates the finished quality of the shrink film or causes the need to appropriately adjust the operating conditions of the shrinking device so that the finished quality of the shrink film does not deteriorate, complicating the work.

[0006] Therefore, a technique for filling the space where steam is supplied for heating and shrinking the shrink film with steam as much as possible is desired.

[0007] One aspect of the present disclosure is a shrink wrapping apparatus. The apparatus of the disclosure is a shrink wrapping apparatus for heating and shrinking a shrink film and attaching it to an object being conveyed in a conveying direction, and may include: a first heating chamber to which steam for heating and shrinking the shrink film is supplied; an exhaust chamber provided on at least one side of the first heating chamber, on the upstream and downstream sides in the conveying direction; and a steam supply device configured to supply steam to the first heating chamber and to resupply at least a portion of the steam that has flowed out of the first heating chamber to the exhaust chamber back to the first heating chamber.

[0008] Another aspect of the present disclosure is a method. The method of the disclosure is a method for heating and shrinking a shrink film and attaching it to an object being transported in a transport direction, comprising supplying steam for heating and shrinking the shrink film to a first heating chamber, and resupplying at least a portion of the steam that has flowed out of the first heating chamber to an exhaust chamber provided on at least one side of the first heating chamber, either upstream or downstream in the transport direction, back to the first heating chamber.

[0009] Further details will be described in the embodiments below. [Brief explanation of the drawing]

[0010] [Figure 1] Figure 1 is a side view of the shrink wrap machine. [Figure 2] Figure 2 is an internal plan view of the shrinking machine. [Figure 3] Figure 3 is a side view of the shrink wrap machine. [Figure 4] Figure 4 is an internal plan view of the shrinking machine. [Modes for carrying out the invention]

[0011] <1. Overview of shrink wrapping apparatus and method>

[0012] (1) The shrink wrapping apparatus according to the embodiment can heat and shrink a shrink film and attach it to an object being conveyed in the conveying direction. The shrink wrapping apparatus may include a first heating chamber to which steam for heating and shrinking the shrink film is supplied; an exhaust chamber provided on at least one side of the first heating chamber, on the upstream and downstream sides in the conveying direction; and a steam supply device configured to supply steam to the first heating chamber and to resupply at least a portion of the steam that flows out of the first heating chamber to the exhaust chamber back to the first heating chamber. In this case, since the flowed-out steam is resupplied to the first heating chamber, the first heating chamber is more easily filled with steam, which is preferable.

[0013] (2) The steam supply device may include a steam generator that generates first steam, and a mixer that generates mixed steam by mixing the first steam with a second steam which is at least a portion of the steam that has flowed out of the first heating chamber to the exhaust chamber. The steam supplied to the first heating chamber may be the mixed steam generated by the mixer. In this case, the mixed steam can be supplied to the first heating chamber.

[0014] (3) The mixer may be equipped with a heater for heating the mixed steam. In this case, it is preferable that the mixed steam supplied to the first heating chamber is heated.

[0015] (4) The steam supply device may be equipped with a heater for heating the steam that is resupplied to the first heating chamber. In this case, it is preferable that the resupplied steam is heated.

[0016] (5) The exhaust chamber may include a first suction port for drawing in a second steam, which is at least a portion of the steam that has flowed out of the first heating chamber into the exhaust chamber, for resupply to the first heating chamber, and a second suction port for drawing in another portion of the steam that has flowed out of the first heating chamber into the exhaust chamber, for exhaust to the outside of the shrinking device. In this case, a portion of the steam that has flowed out into the exhaust chamber is resupplied to the first heating chamber, and the other portion is exhausted outside the device.

[0017] (6) The first suction port may be arranged at a position closer to the first heating chamber than the second suction port when viewed in the conveying direction. In this case, steam can be efficiently recovered and re-supplied.

[0018] (7) The first suction port may be arranged above the second suction port. In this case, steam can be efficiently recovered and re-supplied.

[0019] (8) The first suction port may be at a position closer to the first heating chamber than the second suction port when viewed in the conveying direction and arranged above the second suction port. In this case, steam can be efficiently recovered and re-supplied.

[0020] (9) Preferably, the width dimension of the first heating chamber intersecting the conveying direction is smaller than that of the exhaust chamber. In this case, the first heating chamber becomes narrower, and it is preferable that the first heating chamber is easily filled with steam.

[0021] (10) The shrinking device may be provided upstream of the first heating chamber in the conveying direction and further include a preheating chamber for preheating the target product. The exhaust chamber may be provided between the preheating chamber and the first heating chamber. The first suction port may be arranged at a position closer to the first heating chamber than the preheating chamber when viewed in the conveying direction. The second suction port may be arranged at a position closer to the preheating chamber than the first heating chamber when viewed in the conveying direction.

[0022] (11) The shrinking device may be provided downstream of the first heating chamber in the conveying direction and further include a second heating chamber for heating the target product. The exhaust chamber may be provided between the first heating chamber and the second heating chamber. The first suction port may be arranged at a position closer to the first heating chamber than the second heating chamber when viewed in the conveying direction. The second suction port may be arranged at a position closer to the second heating chamber than the first heating chamber when viewed in the conveying direction.

[0023] (12) The method according to the embodiment is a method of heating and shrinking a shrink film and attaching it to an object to be conveyed in the conveying direction, wherein steam for heating and shrinking the shrink film is supplied to a first heating chamber, and at least a part of the steam flowing out from the first heating chamber is re-supplied to the first heating chamber from the first heating chamber to an exhaust chamber provided on at least one of the upstream side and the downstream side in the conveying direction in the first heating chamber. This may be included.

[0024] <2. Examples of shrinkage devices and methods>

[0025] Hereinafter, embodiments will be described in more detail with reference to the drawings.

[0026] FIGS. 1 and 2 show a shrinkage device 10 according to an embodiment. The shrinkage device 10 heats and shrinks a shrink film. The shrink film is, for example, a thermally shrinkable film formed of polyethylene, polypropylene, or PVC. The shrink film is used, for example, as a label or the like for an object such as a product.

[0027] The object 9 is, for example, a container such as a plastic bottle, a can, or a bottle. For example, beverages, foods, drugs, and medicines are stored in the container. A shrink film before shrinkage is attached to the object 9. The shrink film is heated by the shrinkage device 10 in a state of being attached to the object 9, shrinks, and adheres to the object 9.

[0028] [[ID=

[0029] The shrink wrapping device 10 has a heating unit 300. The heating unit 300 heats and shrinks the shrink film to attach it to the target product 9. A heating chamber 310 is formed inside the heating unit 300. The heating chamber 310 is a space for heating the target product 9.

[0030] The heating section 300 and heating chamber 310 are sometimes referred to as the first heating section 300 and the first heating chamber 310, respectively, to distinguish them from the second heating section 500 and the second heating chamber 510 described later. The heating section 300 and heating chamber 310 may also be referred to as the main heating section 300 and the main heating chamber 310.

[0031] A high-temperature gas is supplied to the heating chamber 310 to heat and shrink the shrink film. The high-temperature gas is, for example, steam (water vapor). In the heating chamber 310, the shrink film can be heated by the steam.

[0032] The shrinking device 10 is equipped with a steam supply device 600 (high-temperature gas supply device 600) to supply steam to the heating chamber 310. The steam supply device 600 is equipped with a steam generator 610 and supplies steam 33, including steam (first steam 31) generated by the steam generator 610, to the heating chamber 310. The steam generator 610 is configured, for example, to generate steam by heating water. Multiple ejection ports 320 are provided inside the heating chamber 310 for ejecting high-temperature gas such as steam.

[0033] Each of the multiple nozzles 320 is connected to a steam supply device 600. Each nozzle 320 ejects steam supplied from the steam supply device 600 towards the target product 9. The multiple nozzles 320 create an airflow that swirls around the target product 9, causing the shrink film attached to the target product 9 to be heated and shrunk.

[0034] As shown in Figure 2, the multiple nozzles 320 are positioned around the object 9 being transported by the conveying device 12, and they eject steam 33 onto the object 9 being transported by the conveying device 12. In Figure 2, as an example, four nozzles 320 are arranged inside the heating chamber 310. In Figure 2, two nozzles 320 are arranged on each side in the width direction (the direction intersecting the conveying direction) of the conveying device 12.

[0035] The shrink wrap device 10 includes at least one or both of the first exhaust section 200, which is provided adjacent to the upstream side in the conveying direction of the heating section 300, and the second exhaust section 400, which is provided adjacent to the downstream side in the conveying direction. In the following description, as an example, the shrink wrap device 10 will be described as having both the first exhaust section 200 and the second exhaust section 400.

[0036] The conveying device 12 is configured to convey the object 9 from at least the first exhaust section 200 to the second exhaust section 400. The object 9 enters the first exhaust section 200 through an opening (not shown) at the upstream end of the first exhaust section 200 in the conveying direction. The object 9 that has entered the first exhaust section 200 is conveyed through the heating section 300 to the second exhaust section 400, and exits the second exhaust section 400 through an opening (not shown) at the downstream end of the second exhaust section 400 in the conveying direction. Each opening may be formed to a size sufficient for the object 9 to pass through.

[0037] The first exhaust section 200 includes a first exhaust chamber 210 as its internal space. The first exhaust chamber 210 is a space adjacent to the upstream side in the conveying direction of the heating chamber 310. The second exhaust section 400 also includes a second exhaust chamber 410 as its internal space. The second exhaust chamber 410 is a space adjacent to the downstream side in the conveying direction of the heating chamber 310.

[0038] The first exhaust chamber 210 and the heating chamber 310 are connected, allowing the object 9 to pass through, and the steam 33 in the heating chamber 310 can flow out into the first exhaust chamber 210. As mentioned above, an opening (not shown) is provided at the upstream end of the first exhaust chamber 210 to allow the object 9 to enter from the upstream side, and unless special measures are taken, the steam in the first exhaust chamber 210 can flow out to the upstream side of the first exhaust chamber 210 through this opening. Also, dry air upstream of the first exhaust chamber 210 flows into the first exhaust chamber 210 through this opening. Unless special measures are taken, the dry air that flows into the first exhaust chamber 210 can flow into the heating chamber 310.

[0039] The first exhaust chamber 210 is a space that prevents steam 33 supplied to the heating chamber 310 from flowing out upstream of the first exhaust chamber 210. The first exhaust chamber 210 is also a space that prevents dry air from flowing into the heating chamber 310 from the upstream side of the heating chamber 310.

[0040] In the diagram, white arrows indicate the flow of steam, and black arrows indicate the flow of dry air.

[0041] The gas in the first exhaust chamber 210 is drawn in by appropriate gas suction devices such as blowers 620 and 710. In other words, the first exhaust chamber 210 is configured as a negative pressure chamber. As a result, gas can flow into the first exhaust chamber 210 from both the upstream and downstream sides, but gas is prevented from flowing out of the first exhaust chamber 210. Therefore, the steam 33 supplied to the heating chamber 310 can flow into the first exhaust chamber 210 on the upstream side, but it is prevented from flowing further upstream than the first exhaust chamber 210. Also, dry air upstream of the first exhaust chamber 210 can flow into the first exhaust chamber 210, but it is prevented from flowing into the heating chamber 310.

[0042] The second exhaust chamber 410 serves the same purpose as the first exhaust chamber 210.

[0043] In other words, the heating chamber 310 and the second exhaust chamber 410 are connected so that the object 9 can pass through, and the steam 33 in the heating chamber 310 can flow out into the second exhaust chamber 410. As mentioned above, an opening (not shown) is provided at the downstream end of the second exhaust chamber 410 so that the object 9 can exit to the downstream side, and unless special measures are taken, the steam in the second exhaust chamber 410 can flow out to the downstream side of the second exhaust chamber 410 through this opening. Also, dry air downstream of the second exhaust chamber 410 flows into the second exhaust chamber 410 through this opening. Unless special measures are taken, the dry air that flows into the second exhaust chamber 410 can flow into the heating chamber 310.

[0044] The second exhaust chamber 410 is a space that prevents the steam 33 supplied to the heating chamber 310 from flowing out downstream of the second exhaust chamber 410. The second exhaust chamber 410 is also a space that prevents dry air from flowing into the heating chamber 310 from the downstream side of the heating chamber 310.

[0045] The gas in the second exhaust chamber 410 is drawn in by appropriate gas suction devices such as blowers 620 and 710. In other words, the second exhaust chamber 410 is configured as a negative pressure chamber. As a result, gas can flow into the second exhaust chamber 410 from both the upstream and downstream sides, but gas is prevented from flowing out of the second exhaust chamber 410. Therefore, the steam 33 supplied to the heating chamber 310 can flow into the second exhaust chamber 410 downstream, but it is prevented from flowing further downstream than the second exhaust chamber 410. Also, dry air downstream of the second exhaust chamber 410 can flow into the second exhaust chamber 410, but it is prevented from flowing into the heating chamber 310.

[0046] The shrink device 10 is equipped with an exhaust device 700 for discharging steam and other gases from the exhaust chambers 210 and 410 to the outside. The exhaust device 700 is equipped with the aforementioned exhaust blower 710 (suction device). The exhaust blower 710 is connected to each of the exhaust chambers 210 and 410 by piping and operates to suck in the gases inside the exhaust chambers 210 and 410 and discharge them outside the shrink device 10.

[0047] The steam supply device 600 is configured to recover not only the first steam 31 generated by the steam generator 610, but also at least a portion of the steam 32 (second steam 32) that flows out from the heating chamber 310 to the exhaust chambers 210 and 410, and to resupply it to the heating chamber 310. In other words, the steam supply device 600 can recycle the steam that flows out to the exhaust chambers 210 and 410. As a result, the heating chamber 310 is supplied with both the first steam 31 generated by the steam generator 610 and the recycled second steam 32. Therefore, the amount of steam 33 supplied to the heating chamber 310 can be increased. Thus, it becomes easier to fill the heating chamber 310 with steam.

[0048] The steam supply device 600 is equipped with a recycling blower 620 (recycling suction device) for recycling the second steam 32. The recycling blower 620 is connected by piping to each exhaust chamber 210, 410 and heating chamber 310, and sucks in the steam 32 from the exhaust chambers 210 and 410 and supplies it to the heating chamber 310. By recycling the steam 32, the pressure of the steam supplied to the heating chamber 310 can be increased. Therefore, the pressure inside the heating chamber 310 can be relatively increased. As a result, the force of the airflow from the heating chamber 310 toward the exhaust chambers 210 and 410 can be increased. Thus, it is possible to effectively prevent gas (especially dry air) from entering the heating chamber 310 from outside.

[0049] The heating chamber 310 is formed to be narrow in order to be easily filled with steam. A narrow heating chamber 310 is preferable because it is easier to fill with steam. To make the heating chamber 310 narrow, for example, the width dimensions W1A and W1B of the heating chamber 310 are smaller than the width dimension W2 of the exhaust chambers 210 and 410.

[0050] Partition walls 351 and 352 are provided inside the heating section 300 so that the widthwise dimensions W1A and W1B of the heating chamber 310 are smaller than the widthwise dimension W2 of the exhaust chambers 210 and 410. The partition walls 351 and 352 are installed near both sides of the conveying device 12 so that the widthwise dimension of the heating chamber 310 is reduced to approximately the width of the conveying device 12.

[0051] Thus, in the shrink wrap apparatus 10 according to this embodiment, the steam is recycled and the heating chamber 310 is narrow, making it easier to fill the heating chamber 310 with steam. As a result, it is expected that the finish of the target product 9 to which the shrink film adheres will be improved.

[0052] Furthermore, in the shrink wrap device 10 according to this embodiment, the positions of the suction ports 251, 252, 451, and 452 in the exhaust chambers 210 and 410 are set so as to effectively prevent gas (especially dry air) from entering the heating chamber 310 from outside the heating chamber 310.

[0053] Specifically, the first exhaust chamber 210 includes a first suction port 251 for drawing in steam 32 for recycling and a second suction port 252 for drawing in steam for exhaust to the outside. The first suction port 251 is connected to a recycling blower 620 via piping. The second steam 32 drawn in from the first suction port 251 is resupplied to the heating chamber 310 by the recycling blower 620. The second suction port 252 is connected to an exhaust blower 710 via piping. The gas (steam and dry air) drawn in from the second suction port 252 is discharged to the outside of the shrink device 10.

[0054] The first suction port 251 is located downstream in the transport direction from the second suction port 252. That is, the first suction port 251 is located closer to the heating chamber 310 than the second suction port 252 when viewed in the transport direction. Also, the first suction port 251 is located above the second suction port 252.

[0055] The first suction port 251 may, for example, be located on the ceiling surface of the first exhaust chamber 210. The second suction port 252 may, for example, be located on the side in the width direction of the first exhaust chamber 210.

[0056] Since the first suction port 251 is located close to the heating chamber 310, more steam flowing out of the heating chamber 310 flows towards the first suction port 251 than towards the second suction port 252. Therefore, the second steam 32 can be efficiently recovered for recycling, and the flow of steam flowing out of the heating chamber 310 upstream of the first exhaust chamber 210 can be suppressed.

[0057] Furthermore, since steam tends to rise, the placement of the first suction port 251 for recycling at an upper position allows for more efficient recovery of the second steam 32.

[0058] Of the steam that enters the first exhaust chamber 210 from the heating chamber 310, any steam that is not recovered by the first suction port 251 and instead flows upstream of the first exhaust chamber 210 is drawn in by the second suction port 252. This prevents the steam flowing upstream from flowing out beyond the first exhaust chamber 210.

[0059] Furthermore, even if dry air flows into the first exhaust chamber 210 from the upstream side, the dry air is immediately drawn in by the second suction port 252 located upstream of the first exhaust chamber 210, preventing it from reaching the heating chamber 310. Moreover, a vapor flow is formed in the vicinity of the heating chamber 310 within the first exhaust chamber 210, with the vapor flowing upwards. This vapor flow acts as a barrier to dry air entering the heating chamber 310. As a result, dry air can be effectively prevented from entering the heating chamber 310.

[0060] The suction ports 451, 451 located in the second exhaust chamber 410 can function in the same way as the suction ports 251, 252.

[0061] Specifically, the second exhaust chamber 410 includes a first suction port 451 for drawing in steam 32 for recycling and a second suction port 452 for drawing in steam for exhaust to the outside. The first suction port 451 is connected to a recycling blower 620 via piping. The second steam 32 drawn in from the first suction port 451 is resupplied to the heating chamber 310 by the recycling blower 620. The second suction port 452 is connected to an exhaust blower 710 via piping. The gas (steam and dry air) drawn in from the second suction port 452 is discharged to the outside of the shrink device 10.

[0062] The first suction port 451 is located upstream of the second suction port 452 in the transport direction. That is, the first suction port 451 is located closer to the heating chamber 310 than the second suction port 452 when viewed in the transport direction. Also, the first suction port 451 is located above the second suction port 452.

[0063] The first suction port 251 may, for example, be located on the ceiling surface of the first exhaust chamber 210. The second suction port 252 may, for example, be located on the side in the width direction of the first exhaust chamber 210.

[0064] Since the first suction port 451 is located close to the heating chamber 310, more steam flowing out of the heating chamber 310 flows towards the first suction port 451 than towards the second suction port 452. Therefore, the second steam 32 can be efficiently recovered for recycling, and the flow of steam flowing out of the heating chamber 310 downstream of the second exhaust chamber 410 can be suppressed.

[0065] Furthermore, since steam tends to rise, the placement of the first suction port 451 for recycling at an upper position allows for more efficient recovery of the second steam 32.

[0066] Of the steam that enters the second exhaust chamber 410 from the heating chamber 310, any steam that is not recovered by the first suction port 451 and instead flows downstream of the second exhaust chamber 410 is drawn in by the second suction port 452. This prevents the steam flowing downstream from flowing further downstream than the second exhaust chamber 410.

[0067] Furthermore, even if dry air flows into the second exhaust chamber 410 from the downstream side, the dry air is immediately drawn in by the second suction port 452 located downstream of the second exhaust chamber 410, preventing it from reaching the heating chamber 310. Moreover, a vapor flow is formed in the vicinity of the heating chamber 310 within the second exhaust chamber 410, with the vapor flowing upwards. This vapor flow acts as a barrier to dry air entering the heating chamber 310. As a result, dry air can be effectively prevented from entering the heating chamber 310.

[0068] As an example, the steam supply device 600 supplies mixed steam 33, which is a mixture of first steam 31 generated by the steam generator 610 and recycled second steam 32, to the heating chamber 310. By using mixed steam 33, the temperature difference between the two steams 31 and 32 can be eliminated, preventing the finish of the target product 9 from deteriorating.

[0069] The steam supply device 600 includes a mixer 630 to generate mixed steam 33. The mixer 630 mixes first steam 31 and second steam 32. The mixer 630 is connected to the steam generator 610 via piping to receive the first steam 31, and is also connected to the recycling blower 620 via piping to receive the second steam 32. The mixer 630 has an internal space (mixing space) into which the first steam 31 and second steam 32 are supplied. The first steam 31 and second steam 32 supplied to the mixer 630 merge within the internal space of the mixer 630 to become mixed steam 33. The mixer 630 may be equipped with a stirring member to promote mixing, but it is sufficient for the merged steams to mix naturally without a stirring member.

[0070] The mixer 630 may be equipped with a heater. The heater heats the steam. For example, the heater heats the mixed steam 33. This makes it possible to raise the temperature of the mixed steam 33 higher than the temperatures of the first steam 31 and the second steam 32. Also, by heating the mixed steam 33, the temperature difference between the two steams 31 and 32 can be eliminated. Furthermore, even if the temperature of the second steam 32 decreases due to recycling, the temperature of the steam 33 supplied to the heating chamber 310 can be made sufficiently high. In addition, by making the mixer 630 smaller and reducing the internal space, the power consumption of the heater can be reduced.

[0071] The heater does not need to be located in the mixer 630; it may be provided separately from the mixer 630.

[0072] Figures 3 and 4 show the shrink wrapping apparatus 10 shown in Figures 1 and 2, with a preheating section 100 connected to the upstream side and a second heating section 500 connected to the downstream side. By providing the preheating section 100 and the second heating section 500, the finish of the target product 9 can be improved. In the shrink wrapping apparatus 10 shown in Figures 3 and 4, the conveying device 12 is provided to convey the target product 9 from the preheating section 100 to the second heating section 500. The target product 9 supplied from the upstream end of the preheating section 100 moves through the inside of the shrink wrapping apparatus 10 in the following order: preheating section 100, first exhaust section 200, first heating section 300, second exhaust section 400, and second heating section 500.

[0073] The preheating unit 100 has a preheating chamber 110 inside and preheats the product 9. The preheating chamber 110 is located upstream of the first heating chamber 310 in the conveying direction. The preheating chamber 110 preheats the product 9 before it is conveyed to the first heating chamber 310. The preheating chamber 110 preheats the product 9, for example, with high-temperature dry air (dry hot air). A first exhaust chamber 210 is located between the preheating chamber 110 and the first heating chamber 310.

[0074] As shown in Figure 4, within the preheating chamber 110, high-temperature air is blown onto the object 9 being transported from both sides in the width direction of the transport device 12. The air ejected from both sides in the width direction of the transport device 12 collides on the transport device 12, changing direction and creating a relatively strong airflow (dry hot air) directed downstream (and upstream) in the transport direction.

[0075] The second heating unit 500 has a second heating chamber 510 inside and heats the object 9. The second heating chamber 510 is located downstream of the first heating chamber 310 in the conveying direction. The second heating chamber 510 heats the object 9 with high-temperature dry air (dry hot air). The second heating chamber 510 dries the object 9, which has been wet by the steam 33 in the first heating chamber 310, by post-heating with dry air. A second exhaust chamber 410 is located between the first heating chamber 310 and the second heating chamber 510.

[0076] As shown in Figure 4, in the second heating chamber 510, a swirling airflow (drying hot air) is generated around the object 9, similar to the first heating chamber 310. An airflow (drying hot air) is also generated from the second heating chamber 510 toward the upstream (and downstream) side in the conveying direction.

[0077] Therefore, in the shrink wrap apparatus 10 configured as shown in Figures 3 and 4, drying hot air is generated from the preheating chamber 110 and the second heating chamber 510, and actively directed toward the first heating chamber 310. When the drying hot air flows into the first heating chamber 310, the first heating chamber 310 is filled with steam, which may degrade the finished quality of the product 9.

[0078] However, the shrink device 10 according to this embodiment can prevent the dry hot air from flowing into the first heating chamber 310 by drawing in the dry hot air through the second suction ports 252 and 452 provided in the exhaust chambers 210 and 410. Moreover, because the amount of steam in the first heating chamber 310 is increased by the recycled steam 32 (second steam 32), and the pressure in the first heating chamber 310 is also increased, it is difficult for the dry hot air to flow into the first heating chamber 310. Therefore, it is preferable to be able to fill the first heating chamber 310 with steam.

[0079] Thus, since the shrink wrap apparatus 10 of this embodiment is equipped with exhaust chambers 210 and 410 on the upstream and downstream sides of the first heating chamber 310, even if a processing chamber that generates drying hot air (for example, a preheating chamber 110 or a second heating chamber 510) is provided on the upstream or downstream side of the exhaust chambers 210 and 410, it is possible to prevent the shrink wrap apparatus from being affected by the drying hot air from that processing chamber.

[0080] The present invention is not limited to the above embodiments, and various modifications are possible. For example, by operating the blower 620 while stopping the steam generator 610 and exhaust blower 710, the target product 9 can also be heated with dry hot air that does not contain steam. In other words, the shrink device 10 shown in Figures 1 and 2 can be used for heating with steam, and if necessary, for heating with dry air. Furthermore, the steam supply is appropriately controlled by a digitally controlled valve, controlling the pressure and other parameters. The exhaust can also be appropriately controlled by a digitally controlled valve. [Explanation of Symbols]

[0081] 9: Target items 10: Shrink wrapper 12: Conveying device 31: First steam 32: Second steam 33: Mixed steam 100: Preheating section 110: Preheating room 200: First exhaust section 210: First exhaust chamber 251: 1st suction port 252:Second suction port 300: 1st heating section 310: 1st heating chamber 320: Spout part 351: Bulkhead 352: Bulkhead 400: Second exhaust section 410: Second exhaust chamber 451: 1st suction port 452:Second suction port 500: 2nd heating section 510: 2nd heating chamber 600: Steam supply device 610: Steam generator 620: Recycled blower 630: Mixer 700: Exhaust system 710: Exhaust fan

Claims

1. A shrink film shrinking device that heats and shrinks a shrink film and attaches it to an object being transported in the transport direction, A first heating chamber to which steam is supplied for heating and shrinking the shrink film, An exhaust chamber provided on at least one side of the upstream and downstream sides in the conveying direction of the first heating chamber, A steam supply device configured to supply steam to the first heating chamber, and configured to resupply at least a portion of the steam that flows out of the first heating chamber to the exhaust chamber back to the first heating chamber, A shrink wrap device equipped with the following features.

2. The steam supply device is A steam generator that produces the first steam, A mixer that generates mixed steam by mixing the first steam with the second steam, which is at least a portion of the steam that has flowed out of the first heating chamber to the exhaust chamber, Equipped with, The steam supplied to the first heating chamber is the mixed steam produced by the mixer. The shrink wrap device according to claim 1.

3. The mixer is equipped with a heater for heating the mixed steam. The shrink wrap device according to claim 2.

4. The steam supply device includes a heater for heating the steam that is resupplied to the first heating chamber. The shrink wrap device according to claim 1.

5. The aforementioned exhaust chamber is A first suction port for drawing in a second steam, which is at least a portion of the steam that has flowed out of the first heating chamber to the exhaust chamber, for resupply to the first heating chamber, A second suction port is provided for drawing in the remaining portion of the steam that has flowed out from the first heating chamber to the exhaust chamber in order to exhaust it outside the shrinking device, Equipped with, The shrink wrap device according to claim 1.

6. The first suction port is positioned closer to the first heating chamber than the second suction port when viewed in the transport direction. The shrink wrap apparatus according to claim 5.

7. The first suction port is positioned above the second suction port. The shrink wrap apparatus according to claim 5.

8. The first suction port is located closer to the first heating chamber than the second suction port when viewed in the transport direction, and is positioned above the second suction port. The shrink wrap apparatus according to claim 5.

9. The first heating chamber has a width dimension intersecting the transport direction that is smaller than that of the exhaust chamber. The shrink wrap device according to claim 1.

10. Further comprising a preheating chamber provided upstream of the first heating chamber in the conveying direction for preheating the target product, The exhaust chamber is provided between the preheating chamber and the first heating chamber. The first suction port is positioned closer to the first heating chamber than the preheating chamber when viewed in the transport direction. The second suction port is positioned closer to the preheating chamber than the first heating chamber when viewed in the transport direction. The shrink wrap apparatus according to claim 5.

11. The system further includes a second heating chamber provided downstream of the first heating chamber in the conveying direction for heating the target product, The exhaust chamber is provided between the first heating chamber and the second heating chamber. The first suction port is positioned closer to the first heating chamber than the second heating chamber when viewed in the transport direction. The second suction port is positioned closer to the second heating chamber than the first heating chamber when viewed in the transport direction. The shrink wrap apparatus according to claim 5.

12. A method for attaching shrink film to an object being transported in the transport direction by heating and shrinking it, Steam is supplied to the first heating chamber to heat and shrink the shrink film. At least a portion of the steam that has flowed out of the first heating chamber to the exhaust chamber located on at least one side of the upstream and downstream sides in the conveying direction of the first heating chamber is resupplied to the first heating chamber. A method that includes the act of doing so.

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