JPH09202314A - Shrink tunnel - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent a defective product due to a rise in temperature or the like in a tunnel when a line stops by providing cooling air nozzles respectively in first and second heating parts and respectively controlling nozzle operation according to a temperature in the heating part. SOLUTION: An internal space along a transfer conveyer 5 with containers B... with a shrinkable label put on mounted comprises a first heating part 6 and a second heating part 7 where heating temperatures are different. Temperature sensors 8, 9 are provided inside the respective heating parts 6, 7, while air nozzles 10, 11 are provided at their entrance, which are controlled by a control panel C according to an internal temperature. The control panel C inputs information of the temperature sensors 8, 9 respectively to first and second temperature adjusters 12, 13, opens/closes respective solenoid valves 17, 18 by a relay 14, a timer 15 and a valve switch 16, respectively, and ejects cooling air from the air nozzles 10, 11. At the time of short stoppage when the inside of a tunnel is likely to be overheated, external air is directly injected from the air nozzles 10, 11 to instantly lower the temperature.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a shrink tunnel for shrink-wrapping a shrink label on the surface of a container.

[0002]

Various containers such as glass, cans, plastics, etc. are used as containers for various beverages including lactic acid bacteria drinks and fermented milk. Shrink labels such as polyvinyl chloride are shrink-wrapped. Shrink packaging of a container can be performed by mounting a shrink label on the container and heating the shrink label to shrink the label. For example, JP-A-55-55918 and JP-A-6-39.
The device described in Japanese Patent No. 713 has been proposed.

However, since the shrink label is sensitive to heat, it cannot be said that the conventional apparatus adjusts the heating temperature sufficiently, and in particular wrinkles, distortion, and excess due to an increase in temperature in the tunnel when the line is stopped. Product defects such as shrinkage may occur.

[0004]

SUMMARY OF THE INVENTION The present invention was devised to solve the problems of the prior art on the premise of the above-mentioned known technology. The heating temperature is sufficiently adjusted, and particularly the line is stopped. It is an object of the present invention to provide a shrink tunnel that is less likely to cause a product defect due to an increase in temperature inside the tunnel.

[0005]

In order to solve the above problems, the present invention relates to a shrink tunnel (continuous heating device for shrink wrapping), wherein the first heating section having different heating temperatures is used. In a shrink tunnel having a conveyer communicating with both heating units and having a second heating unit, an air nozzle for cooling is provided in each heating unit, and the operation of the air nozzle is controlled according to the temperature in the heating unit. For example, when the temperature is suddenly abnormally high, cooling air is ejected from the air nozzles to the respective heating portions by means of the respective members to rapidly lower the temperature in the shrink tunnel.

According to the second aspect of the invention, in addition to the means of the first aspect, the air nozzle is provided on the upstream side in the moving direction of the conveyer conveyor, and the air blowing direction is provided on the moving direction side of the conveyer conveyor. By this, the container on the transport conveyor is operated to be sent out to the outside of the shrink tunnel.

According to the invention of claim 3, claim 1 or 2
In addition to the means described, the shrink tunnel is provided with a heating air supply unit for supplying the air heated by the heaters to the both heating units, so that the hot air from the heating air supply unit hits the side surface of the container to be conveyed. In addition, a temperature sensor is provided inside the heating unit, and a heat circulation member that can take in outside air is provided at the heating air supply unit, and the temperature inside the heating unit is controlled by the control member, so that the side surface of the container to be transported is controlled. It is characterized in that the air heated by the heater is evenly applied and the temperature of the inside of the heating section is quickly controlled by appropriately taking in outside air by the heat circulation member.

According to a fourth aspect of the present invention, in the means according to the third aspect, the heater is composed of a fixed heater and a control heater to enable heating management, particularly rapid heating temperature adjustment. In this case, it is desirable that the calorific value is automatically distributed to the fixed heater and the control heater rather than the temperature of the peripheral portion of the device.

[0009]

First, the background of the present invention will be described. For products such as dairy products and beverages, it is necessary to display the product name, quality retention period, producer, seller, handling precautions, etc. There are many methods such as sticking a label printed on paper or plastic film and attaching a shrink film or shrink label using a heat-shrinkable plastic film, but the use of shrink labels tends to increase recently.

The reason for this is that the cost is higher than direct printing or paper labels, but the area required as a design or display means can be widely used in three dimensions, and a beautiful design can be made on the inner surface of the film by the gravure printing method. That is, since the inner surface is printed, the printed matter is not easily scratched or peeled off by an external force, and the like.

The shrink label has a cylindrical shape, and after it is attached to a solid or a container, hot air, radiant heat,
The method of shrinking and adhering uniformly along the shape of the container, etc. by the thermal energy of steam etc. is used, but in order to take advantage of the characteristic that fine expression can be displayed cleanly and accurately, the label's wrinkle / wrinkle after shrinking・ It is necessary to shrink uniformly so that there is little distortion.

Shrink labels are typically 40-50
Although it is used with a thickness of about μ, thinning technology is advancing rapidly in terms of resource saving and environmental friendliness, and those with a thickness of 30 μ or less have been commercialized. However, the thinner the label, the higher the level of technology required for uniform thickness, and the thinner the thickness, the smaller the uneven thickness that affects the shrinkage balance.
Furthermore, since the shrinkage stress also weakens, it becomes difficult to obtain a tight shrinkage. The present invention was developed in such a situation.

Next, the basic idea of the present invention will be described. The basic idea of the present invention is to provide an air nozzle for cooling in the heating portion of the shrink tunnel as a cooling means for preventing overheating of the shrink tunnel (continuous heating device for shrink wrapping) in order to prevent overheating during a small stop. Moreover, in order to prevent overheating during continuous operation, the circulating air supply unit takes in outside air and automatically controls these operations to keep the temperature inside the tunnel constant The purpose is to heat shrink the shrink label.

The basic structure of the present invention based on the above basic idea is as follows. As shown in FIGS. 1 to 3, the shrink tunnel T is formed in a triple structure by the inner wall 1, the intermediate wall 25, and the outer wall 2, and the intermediate space formed between the outer wall 2 and the intermediate wall 25 supplies the circulating air. The parts 26 and 27 are provided. Further, the space formed between the intermediate wall 25 and the inner wall 1 is the heated air supply units 3 and 4. Furthermore, the inner wall 1
The inner space of is used as a heating unit, and the conveying conveyor 5 is arranged in the heating unit along the length direction thereof, and the container B with the shrink label is mounted on the conveying conveyor 5, In addition, the inner space part is defined as the first heating part 6 and the second heating part 7 along the conveyor 5.

Each of the heating units 6 and 7 is constructed so that hot air is blown from the side surface of the container B, which is conveyed, and temperature sensors 8 and 9 are provided inside the heating units 6 and 7, respectively. There is. The heating air supply units 3 and 4 are provided with heaters, the outer wall 2 above the circulating air supply units 26 and 27 is provided with a fan F for heat circulation capable of taking in outside air, and the heating units 6 and 7 are also provided.
Air nozzles 10 and 11 are provided at the entrance portion of the control panel C and are controlled by the control panel C according to the temperatures inside the heating units 6 and 7.

As shown in FIG. 5, the control panel C uses the information of the temperature sensors 8 and 9 provided in the first heating section 6 and the second heating section 7 as first and second temperature controllers 12, respectively. 13 and the operation relay 14, the timer 15 and the valve switch 16 respectively operate the respective solenoid valves 17,
18 is opened and closed, and air for cooling the inside of each heating unit 6, 7 is ejected from the air nozzles 10, 11. The basic configuration is as described above, and further, specific examples of the present invention will be described with reference to FIGS.

First, the materials of the heat shrinkable film and the container will be described. As the plastic used for the heat shrink film, polyethylene (PE), polypropylene (PP), polyvinyl chloride (PVC), polystyrene (PS), polyethylene terephthalate (PET), etc. are used, but printing display accuracy is required. PVC, PS, PET, etc. are often used for shrink labels.

In addition to all the above materials, glass, cans, papers, etc. can be used as the material of the container B, which is applied to this embodiment, and the material of the shrink label is not only polyvinyl chloride but also polystyrene. , Polyethylene terephthalate, etc. are applied. These materials may be appropriately selected according to the needs of the user.

Next, the structure of the shrink tunnel T will be described mainly with reference to FIG. The shrink tunnel T is formed in a rectangular cross-section as a whole, and the conveyor 5 is arranged in the length direction of the tunnel T inside the shrink tunnel T, and the inner wall 1 thereof is formed.
A large number of outlets 19 ... Constituting hot air holes are provided on the side surface of the. It is desirable that the hole diameter of the outlet 19 and the blowing direction can be adjusted.

It is desirable to provide two stages of guides 20, 20 on both sides of the conveyer 5 along the conveyer 5. These guides 20, 20 are not provided in the container B, ... Place it so that it does not touch. According to this, even if the container falls down during the transportation, the container B is placed in the tunnel T.
There is no risk of being left behind.

As shown in FIG. 4, an outside air intake port 23 provided with a damper 22 is provided in the air passage to the heating air circulating fan F provided in each of the heating air supply units 3 and 4 for control. Opening and closing of the damper 22 is controlled by a solenoid valve in response to a signal from a control panel C that constitutes a member. As a result, the outside air is taken in from the outside air intake port 23, and the temperature inside the circulating air supply units 3 and 4 is adjusted.

A plurality of heaters are provided above the heated air supply units 3 and 4, and are preferably composed of a fixed heater and a control heater. Further, the temperature sensor K inputs information on the ambient temperature to the third temperature controller,
Means shown in FIG. 7 are provided so as to be automatically distributed to the fixed heater and the control heater by the output of the third temperature controller. By such means, it becomes easier to control the amount of heat supplied to the air. The heater may be, for example, an electric heater.

The cooling air nozzles 10 and 11 are respectively installed on the upstream side in the moving direction of the conveyor belt conveyor 5 in the heating units 6 and 7, and the air is jetted toward the downstream side. As for the operation of the injection, the injection of the cooling air (which may be the outside air) is controlled by a signal from the control panel C. Note that the cooling air does not necessarily have to be installed on the upstream side as long as it can quickly reach the inside of the heating section.

Next, the degree of temperature in the heating section will be described. Tunnel T comprising first heating section 6 and second heating section 7
The inside is set so that (first heating part temperature) <(second heating part temperature). The set temperature may be appropriately set according to each material of the container B ... And the shrink label, but when the container B ... Is polystyrene and the label is vinyl chloride, the first heating part temperature is 100 to 180. It is preferable that the temperature of the second heating portion is 160 to 230 ° C.

In addition, the set temperature is adjusted according to the transport distance, transport speed, the temperature of the container B, ... Opening / closing control of the outside air intake port 23 according to the temperature inside the tunnel T, an air nozzle 10 for cooling,
The injection control of 11 and the control of the heater are configured to be independently performed for each of the heating units 6 and 7.

Next, the operation control means of this apparatus will be described. The hot air temperature is detected by the temperature sensors 8 and 9 installed in the central part (center part) of each tunnel, and the sheath heater which is the heat source is controlled. However, if the hot air temperature fluctuates greatly, a defective container will be generated. Usually, when the temperature is lowered by the set temperature, the shrink label shrinks, and the wrinkles and the wrinkles increase. On the other hand, when the temperature is higher than the set temperature, the contracted state tends to be improved, but the container is deformed. Factors that cause the temperature in the tunnel to fluctuate are: insufficient heat capacity of the heater, heater control method, sensor sensing accuracy,
Discontinuous operation of the line, influence of external temperature, etc. are considered.

In order to stabilize the hot air temperature in the tunnel and obtain a good contracted state, it is important to first stably supply hot air having an appropriate temperature to the shrink label. Therefore,
As shown in FIG. 7, the heater was controlled by a non-contact relay, and the fixed heater and the control heater were used in combination to improve the accuracy of heating temperature control. As a result, the hot air temperature in the tunnel was stabilized to about ± 15 ° C with respect to the setting, but it was found that it is not a sufficient countermeasure because it may suddenly reach an abnormally high temperature. Furthermore, in order to improve the control accuracy of the practical temperature range and to stabilize it, cooling control was performed to prevent overheating of the tunnel.

FIG. 5 shows a temperature sensor 8 constituting a temperature measuring element,
9 is a block diagram of operation control of air nozzles 10 and 11 for cooling, which controls opening and closing of solenoid valves 17 and 18 from 9; FIG. FIG. 6 is a flow chart of the operation control, which is a softened version of the block diagram described above. By performing this control by a computer, the solenoid valves 17, 18 are turned on / off to prepare for a sudden abnormal high temperature. . This is a measure for stabilizing the tunnel temperature, which prevents the container from being deformed due to overheating in the tunnel.

The effects of the above embodiment will be described. When the tunnel temperature exceeds the alarm temperature (usually the same temperature as the setting) during a small stop where the inside of the tunnel is likely to be overheated, external air is directly injected from the air nozzles 10 and 11 to instantly lower the temperature. As a result, even when the transport conveyor 5 is stopped, the container B is not heated to a temperature at which it is deformed.

During continuous operation, injecting external air directly into the heating section may cause the container to fall.
The opening of the damper 22 shown in FIG. 2 is adjusted to take in external air, and hot air is blown out into the tunnel T through which the container B passes.
Blow out through 9 ... Since the external air is heated through the heater and is supplied into the tunnel from the hot air outlet 19, the temperature of the entire tunnel can be lowered to the alarm temperature or less as in the case of the small stop.

With these techniques, it is possible to eliminate the generation of several defective containers at the beginning of the flow, which had been manually inspected / removed at the time of re-operation after a small stop, and such work can be performed. An improvement effect such as unnecessary is obtained. Further, according to the present invention, since the temperature inside the tunnel can be stabilized, it can be used not only for individual containers but also for a plurality of batch heat shrinkable packages.

[0032]

According to the present invention, the following effects can be obtained. 1. According to the invention described in claim 1, the temperature in the tunnel can be rapidly lowered by ejecting the cooling air from the air nozzle at the time of the sudden abnormally high temperature, and the deformation of the container in the tunnel can be prevented. At the same time, the temperature inside the tunnel can be stabilized.

2. According to the invention described in claim 2, in addition to the effect of the invention described in claim 1, since the cooling air is ejected from the air nozzle along the moving direction of the container, the direction in which the container is discharged from the tunnel To recover the container
The delivery is smooth, which contributes to improving the operating efficiency of the shrink tunnel.

3. According to the invention of claim 3, in addition to the effect of the invention of claim 1 or 2, in addition to the effect of the invention of claim 1, external air for adjusting the temperature inside the heating portion is passed through the heater before the sudden abnormally high temperature is reached. Since the air is supplied from the outlet into the tunnel, the temperature of the entire tunnel can be quickly lowered to the alarm temperature or less as in the case of the small stop.

4. According to the invention as set forth in claim 4, in addition to the effect of the invention as set forth in claim 3, since the heater is composed of the fixed heater and the control heater, it is easy to perform heating management such as quick transition to the set heating temperature. Become.

[Brief description of drawings]

FIG. 1 is an overall conceptual diagram of a main part of an embodiment of the present invention.

FIG. 2 is a schematic side view of the same.

FIG. 3 is a schematic front view of the same.

FIG. 4 is a sectional view taken along line XX of FIG.

FIG. 5 is a control block diagram of the apparatus of the embodiment.

FIG. 6 is a control flow chart of the apparatus of the embodiment.

FIG. 7 is a control diagram of a heater of the apparatus of the embodiment.

[Explanation of symbols]

 B ... Container C ... Control panel (control member) F ... Fan K ... Temperature sensor T ... Shrink tunnel 1 ... Inner wall 2 ... Outer wall 3 ... (First ) Heating air supply unit 4 ... (Second) heating air supply unit 5 ... Conveyor 6 ... First heating unit 7 ... Second heating unit 8, 9 ... Temperature sensor 10, 11-Air nozzle 12-First temperature controller 13-Second temperature controller 14-Operating relay 15-Timer 16-Valve switch 17,18-Solenoid valve 19-Blowout port 20-Guide 21 .. Perforated guide 22 .. damper 23 .. outside air intake 24 .. heater 25 .. intermediate wall 26, 27 .. circulating air supply unit

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Kazutaka Yamauchi 1-1-19 Higashishimbashi, Minato-ku, Tokyo Yakult Honsha Co., Ltd. (72) Inventor Takumi Saruta 1-1-1, Higashishinbashi, Minato-ku, Tokyo No. 19 Stock Company Yakult Head Office

Claims (4)

[Claims] 1. A shrink tunnel having a first heating part and a second heating part which are different in heating temperature, and a transfer conveyor communicating with the both heating parts is arranged, and air nozzles for cooling are respectively provided in both heating parts. A shrink tunnel in which the operation of the air nozzle is controlled by a control member according to the temperature in the heating section. 2. The shrink tunnel according to claim 1, wherein the air nozzle is provided on the upstream side in the moving direction of the carrying conveyor, and the air blowing direction is provided on the moving direction side of the carrying conveyor. 3. A shrink tunnel is provided with a heating air supply portion for supplying air heated by a heater to both of the heating portions, and hot air from the heating air supply portion is made to hit a side surface of a container to be conveyed. 3. A temperature sensor is provided inside the heating unit, a heat circulating member capable of taking in outside air is provided at the heating air supply unit, and the temperature inside the heating unit is controlled by the control member. Shrink tunnel. 4. The shrink tunnel according to claim 3, wherein the heater comprises a fixed heater and a control heater.