JPS5912522B2 - Mouth sealing device for bag-like containers filled with food - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a device for sealing the opening of a bag-like container filled with food.

In recent years, many cooked foods that are sealed in bag-like containers and subjected to heat sterilization have become popular.

By the way, the materials used for food containers that are heated and sterilized not only have a melting point temperature higher than the sterilization temperature, but also have very few components extracted and transferred from the container material to the food during the heating process, and are resistant to external forces. It must also have sufficient resistance against corrosion and, in some cases, be capable of decorative printing. However, it is rare to find a single material that satisfies all of these five properties, and therefore a film made by laminating several types of materials is usually used. Conventional bag-like containers have an inner layer made of heat-sealable polyethylene, an intermediate layer with aluminum foil to prevent gas permeation if necessary, and an outer layer made of polyester film that is resistant to external forces and can be printed. is used.

Heat sterilization using this bag-like container is usually carried out at 100°C to 1°C.
20-90 in a mixed atmosphere of water vapor and pressurized air at 20℃
However, such long-term processing inevitably leads to loss of nutritional value due to overcooking of the food, and deterioration of quality such as texture and color. On the other hand, recently higher temperatures of 1350C to 150C
By heating and sterilizing at a temperature of 20 minutes, the same sterilization effect as the above can be obtained in an extremely short period of time on the order of 20 minutes, and the high temperature short-time sterilization method (
H, T, S, T method) are being considered.

However, since the melting point of polyethylene is around 130°C25, it is inappropriate to use this polyethylene as a material for the bag-shaped containers for the H, T, S, T method. material must be used.

In order to meet these demands, we developed a material with a thickness of 30mm for the outer layer.
2μ biaxially stretched polyester, 9μ thick aluminum foil and 15μ thick biaxially stretched nylon-6 for the intermediate layer,
There is one in which the inner layer is made of unstretched polypropylene with a thickness of 50 microns, and a polyester-polyisocyanate adhesive is used between each layer to form a 35-layer laminated sheet.

In this case, nylon was added to the intermediate layer to supplement the external strength of polypropylene, and was chosen because it is stronger and cheaper.

However, nylon cannot be used alone for the inner layer due to hygiene issues. In the aforementioned bag-like container material, the nylon-6 used for the middle layer has high absorbency, with a maximum absorbency of 1
Absorbs 0(:f) (weight (f)) of water.

This becomes water vapor during heating when sealing the mouth of the container, generates a large number of bubbles, and significantly reduces the adhesive strength. Similarly, water vapor may be generated explosively and the adhesive surface may peel off. As a countermeasure to this problem, a method can be considered to prevent the nylon from absorbing water by storing the manufactured bag-like container in a vacuum or in a dry atmosphere until it is subjected to the food filling process.

This method is an effective method, and when stored in the above atmosphere, the temperature of the heating bar is 250°C, the pressing time is 0.7 seconds,
Pressure force 1kg/C! 1, a sufficiently strong fused state at the mouth of the container was obtained, and no foaming was observed. However, this method requires separate moisture-proof storage equipment, which causes high costs. In addition, when food is hot-filled into the bag-shaped containers mentioned above at a temperature of 60°C to 100°C, the amount of residual air in the container is reduced, sterilization time can be shortened, and deterioration in food quality can be prevented and the food can last for a long time. It is known that it is possible to produce packaged food products that withstand storage over time. However, when a bag-like container is filled with high-temperature food as described above, a condensable substance mainly composed of water vapor condenses on the inner surface of the container, especially on the opening where heat sealing is performed. Even if the food is heat-sealed, sufficient sealing performance may not be obtained, and the contents may deteriorate after being strained several times, losing its benefits as a packaged food and, in some cases, causing serious hygiene problems. There is sex. The condensed droplets in the heat-sealed part that are generated by hot filling of the contents are caused by steam from the contents, and even if a bag-like container with no moisture in the heat-sealed part is used, the droplets will not heat up. As long as interfill is performed, it will definitely adhere.

Although these condensed droplets are very small, they are distributed throughout the heat-sealed area, so when heat-sealing, they evaporate and expand, creating air bubbles in the heat-sealing area, which become continuous and seal the heat-sealed area. This becomes a through-hole that runs vertically and easily allows bacteria to pass through, causing incomplete sealing. Therefore, in order to hot-fill a bag-like container containing such a highly water-absorbing film and heat-seal the opening, first, the moisture adhering to the opening must be removed by hot-filling. Next, the area to be heat-sealed must be heated while applying a pressing force to heat-seal the opening, and then cooled.

This is because when pressure is applied, the temperature of the heat-sealed part rises and even if heat-sealed, the moisture contained in the nylon cannot evaporate, and when the pressure is released, the temperature of the heat-sealed part has to drop sufficiently. This is because the water contained in nylon cannot evaporate. This invention removes droplets mainly composed of water vapor adhering to the heat-sealed part that causes the through holes as described above, and removes droplets that are mainly composed of water vapor from the intermediate layer such as nylon-6 of the bag-like container as described above. Even if water is absorbed by
It is an object of the present invention to provide a mouth sealing device for a bag-like container that can be heat-sealed with sufficient sealing performance, and to make it possible to obtain packaged foods that can be stored for a long period of time.

That is, the present invention provides an apparatus for heat-sealing the opening of a bag-like container made of a laminated sheet having a metal foil as an intermediate layer and a thermoplastic resin film on both sides while the container is hot filled with food. , a preheating device for removing moisture from the sealing portion, which is equipped with a heating member having a smooth pressing surface and a substantially rigid body and sandwiching the opening of the bag-like container; and a pre-heating device disposed in front of the pre-heating device in the direction of conveyance of the bag-like container. The gist of the present invention is a mouth sealing device for a bag-like container filled with food, which is characterized by comprising a heat-sealing device that is heated and a conveyance mechanism that transfers the bag-like container from a preheating device to the heat-sealing device. .

In a typical device for heat-sealing the mouth of a bag-like container, the surface of one of two heating members sandwiching the mouth is coated with an elastic heat-resistant material such as silicone rubber. This ensures that even pressure is applied to the sealed area.

However, this invention's :=:=2 kinds 2';'. ′：＝←
: If there is an elastic coating like this, moisture will be trapped in the sealing part and it will not be possible to push out the moisture sufficiently.

The heating element of the preheating device must therefore have a substantially rigid surface. Further, the moisture condensed on the sealed portion during preheating can be removed more effectively as the pressing force by the heating member is weaker and the temperature of the heating member is higher. The reason for this is to turn moisture into steam and eliminate it. If the pressing force is higher than the pressure of the steam, the steam will overcome the pressing force and will not be able to escape to the outside of the seal, and if the temperature of the heating member is low. This is because the amount of moisture evaporated is small, so the moisture cannot be sufficiently evaporated before the next heat sealing. Most of the moisture condensed on the sealed part of the bag-shaped container is pushed out of the sealed part by the pressure of the heating member,
The remaining water spreads and intervenes in the form of a film. Therefore, if the pressing force of the heating member is extremely weak, the moisture in the sealing part cannot be pushed out of the sealing part by the pressing force,
There is a lot of moisture remaining in the sealed area, and the moisture cannot be removed sufficiently before the next heat sealing. Furthermore, if the temperature of the heating member is too high, the moisture present in a film on the sealing part will evaporate,
Before being pushed out of the sealed portion, the inner film of the bag-like container fuses and traps moisture, making it impossible to reliably push the moisture out. Room temperature 30℃, humidity 90
01) When a bag-like container made of a laminated sheet containing nylon is left in the atmosphere described above and the contents are hot-filled and the opening is heat-sealed, the preheating is performed so that the temperature of the heating member is 120°C. ~170℃ unless the pressure is 0.5~2kg/d
Moisture could not be removed sufficiently before heat sealing. Furthermore, the heating member of the preheating device needs to be smooth because if the pressing surface is uneven, moisture evaporated by heating will be difficult to escape to the outside of the sealed portion. The heat sealing device of this invention applies electricity only for a very short time while pressing a band-shaped heating wire called an impulse heater, and continues pressing until the fused portion cools down to the extent that it does not peel off, or applies electricity to the heating member. Types with water holes that allow cooling water to pass through at the same time as heating is completed, and types that use high-frequency induction heating are used.

In particular, high-frequency induction heating coil devices have cooling water holes inside themselves to prevent burnout due to self-heating.
Since the temperature is maintained at almost room temperature, it is preferable to continue pressing the sealed portion for a while even after the induction heating coil device has finished energizing it, thereby functioning as a cooling means. Further, it is preferable that the heating member of the sealing device presses the sealing portion with a pressure greater than the saturated water vapor pressure at the temperature of the nylon layer in a molten state, since foaming of the nylon layer will not occur. Even during electrical heating, the surface of the outer layer that is in contact with the induction heating coil device is cooled by the induction heating coil device. The surface of the resin film will not melt. However, lowering the temperature of the induction heating coil device more than necessary will reduce efficiency. For these reasons, high frequency induction heating method
The sealing of the bag-shaped container made of the laminated sheet containing nylon described above is performed using a power source of 100 KHz and 13 KW at 0.1 to 0.2
It is preferable to energize the induction heating coil for a second, run tap water at 20° C. through the coil, and continue to press for about 0.25 seconds after the energization ends to cool the coil. Embodiments of the present invention will be described below with reference to the drawings.

The bag-like container 1 shown in FIG. 1 is made of laminated sheets, including a polyester film 5 as an outer layer, a nylon-6 film 3 and an aluminum foil 4 as an intermediate layer, and a polypropylene film 2 as an inner layer.

An apparatus for hot filling the bag-like container 1 with contents and heat-sealing the opening will be described with reference to FIG. 2.

The bag-shaped container 1 supplied from the container supply device 11 is opened by the opening device 12, and the bag-shaped container 1 supplied from the contents supply device 13 is opened.
The bag-shaped container 1 is filled with contents at 00C to 100C.

Next, the moisture condensed on the inner surface of the mouth of the bag-shaped container 1 is removed by the preheating device 14, and sent to the heat sealing device 15, where the mouth seal is firmly heat-sealed, and the heat-sealed portion is sealed under pressure. cooled down. According to the present invention, since the heat-sealing device 15 also serves to cool the heat-sealed portion, no particular cooling device is required, but the heat-sealed portion is cooled again by the cooling device 16 if necessary. Further details of this device will be explained.

FIG. 2 shows an automated heat sealing apparatus of the rotating station type.

In the figure, the transport mechanism includes a rotating disk 21, which is intermittently driven clockwise as shown by arrow A by a driving electric motor 22. Six carriers 23 are fixed to the outer periphery of the disk 21 at equal angular intervals, and as the disk 21 rotates, they repeatedly stop and move at each station position. The rotational speed of the disk 21 is set to 12 seconds per revolution, the stopping time at each station position is 1 second, and the moving time is also set to 1 movement. Carrier 23 is the third
As shown in detail in the figures, it includes a mechanism for removably locking the bag-like container. A movable arm 25 is slidably attached to a support plate 24 fixed to the disk 21.
A fixed chuck pawl 29 is attached to the tip of 5. A movable piece 27 is slidably attached to the movable arm 25 and is biased in the direction of arrow B by a spring 28. A movable chuck pawl 26 is integrally molded on a part of the movable piece 27, and chuck parts 30 and 31 made of an elastic material such as rubber and having uneven surfaces are provided on the chuck surfaces of the movable chuck pawl 26 and the fixed chuck pawl 29. It is being The movable piece 27 is biased in the direction of arrow B by the spring 28, so that both the chuck claws 26 and 29 are attached to the bag-like container 1.
You can grasp the side edge of the A roller 32 rotatably provided at the tip of the movable piece 27 is not shown in FIG. 3, but cooperates with other cam surfaces etc. to slide the movable piece 27 against the biasing force of the spring 28. and open the chuck claws 26 and 29. The movable arm 25 is disposed so as to be slidable along a long hole 33 provided in the support plate 24.
A fixed arm 34 is fixed to the support plate 24 in parallel with the movable arm 25, and the movable arm 25 and the fixed arm 34 are connected by a link mechanism 35. Link mechanism 35
A spring 36 is provided to bias the movable arm 25 in the direction of arrow C. The top of the link mechanism 35 engages with another cam surface (not shown), etc., and the position of the movable arm 25 is controlled. The structure of the chuck portion of the fixed arm 34 is as follows:
Since it has the same structure as that of the movable arm 25, the explanation will be omitted. In FIG. 2, a container supply device 11 is arranged at the first station position.

This supply device 11 is equipped with a device for accumulating bag-like containers and a vacuum chuck device. At the first station,
The bag-shaped containers 1 are held one by one by a carrier 23, as shown in FIG. At the first station, the link mechanism 35 is pushed down by a cam (not shown), and the arms 25 and 34 grip the bag-like container 1 in an open state. The disk 21 is driven intermittently to carry the carrier 23 to the opening device 12 provided at the second station, but in the middle of this movement, the link mechanism 35 is disengaged from the cam, and the arms 25 and 3
4 becomes narrower. When the carrier 23 reaches the second station and stops, the vacuum chuck mechanism of the opening device 12 sucks both sides of the bag-shaped container 1 and opens the container 1. The opened bag-like container 1 is carried by a carrier 23, stops at a third station constituting the contents supply device 13, and the bag-like container 1 is filled with the food contents. The carrier 23 then moves to a fourth station equipped with a preheating device 14, which is a device for eliminating moisture condensed on the seal.
Until the work process at the third station is completed, the arms 25 and 34 of the carrier 23 keep the distance between them narrow as shown in FIG. 3 and open the bag-like container 1, but they move to the fourth station. Carrier 23 while coming
The link mechanism 35 is pressed again by the action of a cam (not shown) and stretches the sealed portion of the bag-shaped container 1 linearly.
The preheating device 14 is constructed as shown in FIGS. 4A and 4B.

Two fixing bars 38 and 39 are fixed to a device board (not shown). A movable bar 42 is fixed to the rods 40 and 41, and another movable bar 43 is also slidably supported. The latter movable bar 43 has rods 44,4
5 is fixed, and both rods 44 and 45 are attached to the fixed bar 38.
, 39 and the movable bar 42 in a slidable manner.
At the ends of the rods 40 and 41 there is a first preheating bar 4.
6 is fixed, and a second preheating bar 47 is fixed to the tips of the rods 44 and 45. Fixed bar 39
A spring 50 is stretched between a support pin 48 provided on the movable bar 43 and a support pin 49 provided on the movable bar 43, and urges the movable bar 43 in the direction of arrow D. A spring 53 is stretched between a support pin 51 provided on the movable bar 38 and a support pin 52 provided on the movable bar 42 to bias the movable bar 42 in the direction of arrow E. Rollers 56 and 57 are rotatably supported at the lower ends of the movable bars 42 and 43 by support shafts 54 and 55. Between the movable bars 42 and 43 are rollers 56 and 57.
sloped surfaces 58 and 59 on both sides thereof so as to be in sliding contact with the
A pressure member 60 having a pressure member 60 is provided, and a preheating means is driven by a drive shaft 61 fixed to the pressure member 60. The pressure member 60 is held in the raised position until the carrier 23 moves to the fourth station, and the movable bar 42
and 43 are biased in the E and D directions, the first and second preheating bars 46 and 47 are kept open. When the carrier 23 is set at the fourth station, the drive shaft 61 is pushed down in the direction of arrow F by a cam (not shown) interlocking with the disk 21. Therefore, the movable bars 42 and 43 are moved by the urging force of the springs 50 and 53, and close the first and second preheating bars 46 and 47, pressing the sealing portion of the bag-like container. Preheat. Note that the pressing force in this case is adjusted by changing the tensile force of the springs 50 and 53. FIG. 5 shows the structure of a preheating bar 46 for removing moisture condensed on the sealing portion performed at the fourth station.

The preheating bar 46 has a cartridge-shaped heater 46c and a thermostat 46d embedded in a bar body 46b made of a substantially rigid body having a smooth surface 46a, and maintains the bar body 46b at a predetermined temperature. Note that the other preheating bar 47 also has a similar structure to the heating bar 46 described above. The bag-shaped container 1 from which moisture has been removed from the sealed portion as described above is moved to a fifth station equipped with a heat sealing device 15.

The heat sealing device 15 has substantially the same structure as the preheating device 14 described above except for the heating member 62 and the receiving member 63 shown in FIG. Therefore, the heating member 62 and receiving member 63 of the impulse heater shown in FIGS. 6 and 7 will be explained. The heating part 62 is formed of a belt-shaped heating wire 64 with a pressing surface made of stainless steel and a nickel chromium alloy with a thickness of 0.05 to 0.1 m7n. Insulator 66
Fixed. The pressing surface of the receiving member 63 is made of silicone rubber 67, and the kneading member is fixed to a heat-resistant insulator 68 such as Bakelite. Then, the heating member 62 seals the sealed portion of the bag-like container 1 filled with contents and water removed.
The heating wire 64 and the silicone rubber 67 of the receiving member 63 are pressed together, and the heating wire 64 is energized for a short time to heat seal the sealed portion. The bag-shaped container 1 heat-sealed as described above is placed in the sixth bag.
After the sealed portion is cooled and strengthened by an appropriate means (not shown), the chuck by the carrier 23 is released between the sixth station and the first station, and the carrier 23 and returned to the first station, and the operations described above are repeated.

The heat sealing device 15 may be one using high frequency induction heating instead of an impulse heater.

As shown in FIG. 8, the high-frequency induction heating coil device of this heat sealing device has a leakage magnetic flux Q that interlinks only with the ineffective side 69a.
In order to reduce the short-circuiting coil 70, one side thereof is placed close to the ineffective side 69a of the heating coil 69, and a short-circuiting current path surrounding the magnetic circuit of the magnetic core 71 is formed.

When the short circuit coil 70 is provided as shown in FIG. 8, the leakage magnetic flux Q interlinks with the short circuit coil 70, so a current flows in the short circuit coil 70 in a direction that cancels out this leakage magnetic flux Q. As a result, The leakage magnetic flux Q is canceled by the short circuit coil 70, and the mutual induction coefficient of the heating coil increases. Although the shorting coil 70 in FIG. 8 is made of a wound coil of copper wire, it is also possible to form the shorting coil with a conductive metal plate.

An example in which a metal mount to which a heating coil is fixed also serves as a short-circuiting coil is shown in FIGS. 9 and 10. In this example, the mount 72 is made of brass, which has high electrical conductivity and mechanical strength and is easy to process, and serves as a short circuit coil. The mounting base 72 is made of a rod having a substantially U-shaped cross section, and is fixed to a movable bar 73 of a heat sealing device for bag-shaped containers with screws 74, as shown in FIG. A magnetic core 71 made of ferrite and having a U-shaped cross section is fixed to the mounting base 72 in the longitudinal direction. A pipe 75 is further embedded in the magnetic core 71, and this pipe 75 is used to remove the heat generated by the heating coil device during the heat sealing process of the bag-shaped container.
It is for flowing water. Heating side 6 of heating coil 69
9b is fixed to the front surface of the pipe 75, and its ineffective side 69a is fixed to the mounting base 72, and as a result, the heating coil 69 is fixed to the magnetic core 7.
1. In this state, the mounting base 72
A short-circuit current path surrounding the magnetic circuit of the magnetic core 71 is formed by a side portion 72a close to the ineffective side 69a and an end portion 72b on the opposite side thereof, and the leakage magnetic flux due to the ineffective side 69a is absorbed. Further, copper protection plates 76 and 77 are fixed to the front surfaces of the heating side 69b and the ineffective side 69a of the heating coil 69.
9 is prevented from being damaged. In order to perform sealing by high-frequency induction heating using the heating coil device configured as described above, there are two methods: using two substantially identical heating coils to press the sealing portion of the bag-like container with the heating side, and using one heating coil. There is a method in which the heating side of the heating coil is pressed against the sealing part, and the magnetic core of the heating coil and the magnetic core to form the magnetic circuit are arranged on the opposing side.

After pressing the sealed portion with this heating coil device, high-frequency power is supplied, and after the sealed portion is melted, the supply of high-frequency power is stopped.

After the temperature of the sealed portion has sufficiently decreased, the pressure applied by the heating coil device is released. As explained in detail above, according to the apparatus of the present invention, since the preheating device for removing moisture from the heat-sealing portion of the above-described configuration is provided, moisture condensed on the inner surface of the sealing portion of the bag-like container can be removed. When heat-sealing the opening, heating and cooling can be performed while applying pressure, so even bag-like containers made of water-absorbent films such as nylon can be sealed with good sealing properties, allowing the contents to be sealed. It is possible to provide a food package that can be stored for a long period of time without spoiling.

[Brief explanation of drawings]

FIG. 1 is a side sectional view showing an example of a bag-like container sealed by the apparatus of the present invention, FIG. 2 is a schematic plan view showing an embodiment of the present invention, and FIG. 4a and b are a perspective view and a side sectional view of the preheating device, FIG. 5 is a perspective view of the heating bar, FIG. 6 is a side sectional view of the heating member and receiving member of the heat sealing device, and FIG. 7 is a side sectional view of the heat sealing device. Perspective view of the heating member, No. 8
The figure is a side sectional view of the main part showing an example of a heat sealing device using high frequency induction heating, and FIGS. 9 and 10 are a perspective view and a side sectional view of the main part showing other examples. 1... Bag-shaped container, 11... Container supply device, 13... Contents supply device, 14...
・Preheating device, 15... Heat sealing device, 21.
...Rotating disk, 23...Carrier,
46, 47... Preheating oven.

Claims (1)

[Claims] 1. In an apparatus for heat-sealing the opening of a bag-like container made of a laminated sheet having a metal foil as an intermediate layer and a thermoplastic resin film on both sides, while the container is hot filled with food,
a preheating device having a smooth and substantially rigid pressing surface and having two preheating bars for pinching the opening of the bag-like container to remove moisture from the mouth portion; A food-filled container characterized by comprising: a heat sealing device for sealing the mouth of the heated bag-like container; and a transport carrier for delivering the bag-like container from the preheating device to the heat sealing device. Mouth sealing device for bag-like containers.