JPH0752905A - Tube-shaped container sealing and device therefor - Google Patents

Abstract

PURPOSE:To enable secure and high productive sealing of a tube-shaped container. CONSTITUTION:In a method of sealing tube-shaped containers T, nipped with a pressure device 9, by crimping through high-frequency induction heating, a pair of crimping devices 9A, 9B constituting the pressure device 9 are provided with respective tertiary coils, to which voltage is applied toward each other.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a tubular container sealing method and device.

[0002]

2. Description of the Related Art Conventionally, there is a method and apparatus for sealing a tubular container as described in JP-A-2-180124. This conventional technology uses a tubular container laminated with metal foil,
When heating and sealing by high-frequency induction heating, a high-frequency current is supplied to the primary coil by a high-frequency oscillator to move the secondary coil with respect to the primary coil so that the secondary coil approaches the primary coil. While a high frequency current is generated in the secondary coil by electromagnetic induction of the primary coil, a high frequency current is applied to the tertiary coil of a pressurizing device including a tertiary coil connected to the secondary coil. And the tube-shaped container sandwiched by the pressure device is subjected to high-frequency induction heating, pressure-bonded by the pressure device, and sealed.

In this prior art, as shown in FIG. 7 (A), while a high-frequency current is applied to each of the tertiary coils provided in each of the pair of crimping tools which constitute the pressurizing device, a tubular shape is formed by both crimping tools. The container will be heated by high-frequency induction, pressure-bonded, and sealed.

[0004]

However, in the prior art, the energizing directions of the respective tertiary coils provided in each of the pair of crimping tools constituting the pressurizing device are set to be opposite to each other ( FIG. 7 (A)) has the following problems.

Empirically, the sealing portion of the tubular container has a convex shape in the width direction of the container (FIG. 8 (A)), and there is a tendency that the pressure bonding width at both side edges of the container becomes small. On the other hand, the tubular container is formed by flattening and sealing an annular sheet, and the annular sheet is deformed by turning from an annular shape to a U shape. To do. For this reason, in the conventional tubular container where the crimp width on both side edges of the container is small, the above-mentioned restoring behavior to the annular shape continues for a long time on both side edges of the container where the crimp width is small when used after filling the contents. There is a risk that it will act, and eventually the sealing part will peel off from the side edges of the container, causing leakage of the contents.

[0006] The power consumption or heating time required to obtain a required pressure-bonded state (constant seal strength) on the sealing portion of the tubular container is empirically excessive, resulting in poor productivity.

An object of the present invention is to reliably seal a tubular container and to improve its productivity.

[0008]

According to the present invention as set forth in claim 1, when a tubular container laminated with a metal foil is heated and sealed by high frequency induction heating, a high frequency current is applied to a primary coil by a high frequency oscillator. The secondary coil is supplied to move the secondary coil with respect to the primary coil, and while the secondary coil is approaching the primary coil, a high frequency current is applied to the secondary coil by electromagnetic induction of the primary coil. A high frequency current is generated in the tertiary coil of the pressurizing device including a tertiary coil connected to the secondary coil to generate high frequency induction heating of the tubular container sandwiched by the pressurizing device. In a method for sealing a tubular container which is crimped and sealed by the pressure device, the energization directions of the respective tertiary coils provided in each of the pair of crimping tools constituting the pressure device are set to be in the same direction. One in which the.

According to a second aspect of the present invention, in addition to the first aspect of the present invention, the tubular container is provided with a heat-fusible material inside a metal foil.

According to a third aspect of the present invention, when a tubular container laminated with a metal foil is heated by high frequency induction heating and sealed, a primary coil fixedly installed and connected to a high frequency oscillator, and the primary coil A secondary coil that is movable toward and away from the coil and that generates a high-frequency current by electromagnetic induction from the primary coil; a tertiary coil that is connected to the secondary coil and through which the high-frequency current flows; In a device for sealing a tubular container, which comprises a coil and is provided with a pressure device for high-frequency induction heating and pressure-bonding the tubular container by the high-frequency current, the pressure device comprising a pair of pressure-bonding tools, A tertiary coil is provided in each of the pair of crimping tools, and the secondary coil and each tertiary coil are connected so that the energization directions of the respective tertiary coils are the same. It is obtained by the.

[0011]

[Effects] The energizing directions of the respective tertiary coils provided in each of the pair of crimping tools constituting the pressurizing device are set to be in the same direction as shown in FIG. 7B, so that the sealing portion of the tubular container is Can be made concave in the width direction of the container (FIG. 8 (B)), and a stable sealed state can be formed in which the sealing portion is difficult to separate from both side edges of the container. That is, in the tubular container formed by flattening the annular sheet, even when the habit of restoring the annular shape acts on both side edges of the container, the crimping width of the both side edges of the container is in the middle part of the other container width direction. Since it is larger than the above, the both side edge portions of the container can sufficiently endure the above-mentioned restoring behavior to an annular shape and become difficult to peel off.

The difference in the form of the sealing portion obtained by the conventional method (FIG. 7A) and the method of the present invention (FIG. 7B) will be examined below.

First, according to the law of conservation of energy, the magnetic energy (E ₀ ) generated by each tertiary coil of each of the pair of crimping tools constituting the pressurizing device is expressed by the following magnetic equation (1). energy (E _V) the magnetic potential energy (E
_H ) (= scalar potential). _{E 0 = E V + E H} ... (1)

Here, the following equation (2) is established between the magnetic kinetic energy (E _V ) and the thermal energy (E _TH ), and this thermal energy (E _TH ) causes the sealing portion of the tubular container. It is consumed as energy for heating and pressure bonding.

[Equation 1]

[0015] Therefore, if it is possible to determine the distribution of the magnetic kinetic energy each tertiary coil is generated in the container width direction of the tube-like container of the pressure device (E _V), thermal energy acting on the vessel width direction (E _It is possible to estimate the distribution of _TH ), and thus the crimp width distribution. However, this magnetic kinetic energy (E
It is not easy to find the distribution of _V ). Therefore, the present inventor calculates the magnetic potential energy (E _H ) exerted by each tertiary coil of the pressurizing device in the container width direction of the tubular container as follows, and from the calculation result, the magnetic kinetic energy (E _H ) is calculated.
_We decided to estimate the distribution of _V ) based on Eq. (1).

That is, the conventional method (mutual current reverse direction) is shown in FIG.
(A), when the method of the present invention (mutual currents in the same direction) is modeled as shown in FIG. 9B, the scalar potential (magnetic potential energy) in the Z direction of the magnetic field is A _Z , and the conductor wire length of each tertiary coil Is L and the current of the lead wire is I,

[Equation 2] Is. Then, in the conventional method (mutual current reverse direction), A _AZ and A _BZ that each of the above-mentioned pair of tertiary coils exerts on the point P are as in the following formulas (5) and (6).

[Equation 3]

On the other hand, in the method of the present invention (mutual current in the same direction), A _AZ and A _BZ exerted on the point P by each of the above-mentioned pair of tertiary coils are expressed by the following equations (7) and (8). Become.

[Equation 4]

Since the equations (5) ... (8) are basically equations having the same structure, when the equation (5) is integrated,

[Equation 5] It becomes formula (9).

When the magnetic potential energy in the width direction of the pressurizing device is obtained, the sealing point (sealing work area) of the tubular container is performed at the center of the conductor, and the skin effect is 21
In case of 0KHz, it is about 0.15mm. The conditions are shown below.

[Equation 6] Here, δ is the thickness (mm) due to the skin effect, f is the frequency (high frequency) (Hz), a is 1/2 (mm) of the absolute value of the seal width, ρ is the resistivity (mmΩ), and μ ₀ is the transparency. Magnetic susceptibility (copper body) (s / mm), x represents the position (mm) where high frequency flows.

In equation (9)

[Equation 7] If the condition of Eq. (10) is applied and the integration range is 0 → L,

[Equation 8] It becomes formula (11).

Based on the equation (11), the xy plane (Z = 0)
We also fold symmetrically with respect to 0 → -25. That is, using the formula (11), the pressure device width direction -25 to 25
Calculate the magnetic potential energy in mm.

The following equation is obtained by using the equation (11) and the principle of superposition. [When mutual currents are in opposite directions] (conventional method)

[Equation 9]

FIG. 10A shows the position of the tubular container in the width direction of the container and the scalar potential A _Z based on the equation (12).
It is a diagram showing (= magnetic potential energy E _H ).

[When Mutual Currents are in the Same Direction] (Invention Method)

[Equation 10]

FIG. 10B shows the position of the tubular container in the width direction of the container and the scalar potential A _Z based on the equation (13).
It is a diagram showing (= magnetic potential energy E _H ).

Therefore, in the equation (1) of the above-mentioned energy conservation law, the magnetic potential energy (E) shown in FIGS.
If the calculated value of _H ) is applied, as shown in FIG. 11, (a) in the conventional method in which the magnetic potential energy (E _H ) at both side edges of the container is large, the thermal energy (E _TH ) becomes smaller and the crimping width becomes smaller, and the sealing part becomes convex in the container width direction (Fig. 11 (A)), and (b) magnetic potential energy (E _H ) at both side edges of the container is small. In the method of the present invention, it is recognized that the thermal energy (E _TH ) at both side edge portions of the container is large and the pressure bonding width is large, and the sealing portion is concave in the container width direction (FIG. 11 (B)).

The energizing directions of the respective tertiary coils provided in each of the pair of crimping tools constituting the pressurizing device are set in the same direction as shown in FIG. 7B, so that the sealing portion of the tubular container is closed. In addition, the power consumption required to obtain the required pressure-bonded state (constant seal strength) or the heating time is reduced, and the productivity can be improved.

The conventional method (FIG. 7 (A)) and the method of the present invention (FIG. 7 (B)) are simulated below, and the magnitude of the magnetic field H _x that contributes to the adhesion of the sealing portion under the same current supply condition is examined. In both the conventional method and the method of the present invention, the simulation conditions were such that the interval (distance between conductors) between the respective tertiary coils of the pressurizing device was 4 mm, and the current value was 10 A.

FIG. 12 (A) shows the simulation result of the conventional method, and the magnetic field H _X that hits the sealing portion of the tubular container vertically and contributes to the adhesion was 26.6 Wb. On the other hand, FIG. 12 (B) is a simulation result of the method of the present invention, and the magnetic field X _x that hits the sealed portion of the tubular container vertically and contributes to the adhesion was 42.1 Wb. H _y is a magnetic field that is parallel to the sealed portion and does not substantially contribute to adhesion.

According to FIGS. 12 (A) and 12 (B), in the method of the present invention, the magnetic field H _{x, which} is perpendicular to the sealing portion of the tubular container and contributes to the adhesion, is 1.6 times that of the conventional method.
It is confirmed that the number of thermoelectrons hitting the sealed portion is also increased in proportion to this, the power consumption efficiency is improved, the heating time based on the same power consumption is reduced, and the productivity is improved.

[0031]

FIG. 1 is a schematic view showing the overall construction of an embodiment of the sealing device, FIG. 2 is an enlarged view of the essential parts of FIG. 1, FIG. 3 is a sectional view of the essential parts of FIG. 1, and FIG. 4 is a tubular container. Schematic diagram showing the loading state,
FIG. 5 is a schematic diagram showing a thermocompression bonding state of a tubular container, FIG. 6 is a schematic diagram showing a carrying-out state of the tubular container, FIG. 7 is a schematic diagram showing a coil connection structure of a heating device, and FIG. 8 is a tubular container. FIG. 9 is a schematic view showing the form of the sealing part, FIG. 9 is a schematic view showing the coil energization direction of the pressurizing device, FIG. 10 is a diagram showing the container width direction position of the tubular container and the scalar potential, and FIG. 11 is a tubular container. Fig. 12 is a schematic diagram showing the heat energy distribution in the sealed part of Fig. 12, Fig. 12 is a schematic diagram showing the magnetic field hitting the sealed part of the tubular container, and Fig. 13 is a table showing the effect of the method of the present invention.

First, one embodiment of the tubular container sealing apparatus of the present invention suitable for carrying out the method of the present invention will be described with reference to FIGS.
This will be described with reference to FIG.

As shown in FIG. 1, in the apparatus A of the present embodiment, a tube-shaped container T laminated with a metal foil such as an aluminum foil is carried into the apparatus A of the present embodiment, and a carrying-in apparatus B is carried out and then carried out. The tubular container T sealed by the example apparatus A is arranged adjacent to the carrying-out apparatus C that carries out the tubular container T from the apparatus A of the present embodiment and carries it to the next step.

However, the device A of the present embodiment has the rotary table 1 and the rotary table 1 below the peripheral edge of the rotary table 1.
And a plurality of holders 2 that are arranged so as to be able to move up and down in synchronization with. The holder 2 reaches the lowest point at the time of delivering the tubular container T in the carry-out device C, and gradually rises while receiving the tubular container T from the carry-out device C via the carry-in device B. Is configured.

On the other hand, above the rotary table 1, a primary coil 3 which covers a part of the peripheral portion of the fixed table with a constant width is fixedly arranged, and the primary coil 3 is supplied with a high frequency wave through a feeder 4. An oscillator 5 is connected, and the high frequency oscillator 5 supplies a high frequency current to the primary coil 3.

A plurality of secondary coils 6 are arranged at equal intervals around the entire circumference of the rotary table 1 so as to correspond to the holders 2, and the rotary table 1 is rotated to rotate the secondary coils 6.
The secondary coil 6 has a slit δ below the primary coil 3 (FIG. 3).
The secondary coil 6 is configured to generate a high frequency current by an electromagnetic induction phenomenon of the primary coil 3 due to the high frequency current. The tubular container T is composed of PE / milk white PE / PE / paper / adhesive layer / aluminum 15μ / adhesive layer / PE 45μ from the outer layer, and the total is about 300.
In the case of μ, it can be sealed by setting the slit δ to about 5 mm, but it is preferable to make the slit δ as small as possible in order to improve the efficiency of electromagnetic induction.

Therefore, the relationship between the primary coil 3 and the secondary coil 6 will be described in more detail with reference to FIGS. 2 and 3.
As shown in FIG. 2, the primary coil 3 is formed as a rectangular body in which a hollow conductor has four turns and is elongated and curved, and the secondary coil 6 is formed as a substantially square body in which the hollow conductor is made one turn. ing. Furthermore, as shown in FIG. 3, the hollow conductor forming the secondary coil 6 is the rotary table 1
2 is formed so as to extend vertically downward through the hole 1A formed in the above, and a horizontally long rectangular body portion 6A as shown in FIG. 2 is formed at the lower end of the extension. Then, the tertiary coil 7A that has been turned two times is superposed and joined to the rectangular body portion 6A, and the other three turns that are turned three times through the flexible feeder 8 to the tertiary coil 7A.
Next coils 7B are arranged to face each other to form a pair,
The secondary coil 6 and the pair of tertiary coils 7A and 7B form a substantially orthogonal positional relationship.

Further, water or turbine oil or the like is circulated as a cooling medium in the hollow of the circular pipe-shaped hollow conductor forming the primary coil 3, the secondary coil 6 and the tertiary coils 7A, 7B, and a high frequency current is passed. It is designed to prevent heating due to continuity of.

However, when the secondary coil 6 reaches below the primary coil 3 due to the rotation of the rotary table 1, a high frequency current is applied to the secondary coil 6 by the electromagnetic induction of the primary coil 3 as described above. And a pair of the tertiary coils 7A and 7B connected to the secondary coil 6.
Similarly, a high-frequency current flows (generates a high-frequency current).

As shown in FIGS. 1 to 3, the tertiary coils 7A and 7B are respectively incorporated in crimping tools 9A and 9B forming a pair of a pressurizing device 9 for holding the open end of the tubular container T. The magnetic flux generated in the tertiary coils 7A, 7B is configured to generate an eddy current in the metal foil forming the tubular container T sandwiched between the crimping tools 9A, 9B for high frequency induction heating. .

Of the pair of crimping tools 9A and 9B, the crimping tool 9A located inside the rotary table 1 is fixed, while the crimping tool 9B located outside is fixed by the rod 10. ing. When the tubular container T reaches the rising end by the operation of the holder 2,
The rod 10 is advanced to sandwich the open end of the tubular container T with the crimping tools 9A and 9B, and as described above, the open end of the tubular container T can be crimped by high frequency induction heating. ing.

Therefore, in the present embodiment, the pressure device 9
Each of the tertiary coils 7A and 7B contained in each of the pair of crimping tools 9A and 9B is connected via a flexible feeder 8 in a cross shape so that their energizing directions are the same. It is connected to the next coil 6 (FIGS. 1 to 3 and FIG. 7B).

The fixed primary coil 3, the rotatably movable secondary coil 6, the heating tertiary coil 7A,
An insulator such as bakelite is used to protect each of the 7Bs, thereby preventing energy loss due to heat generation and ensuring safety.

In particular, the crimping tools 9A and 9B containing the tertiary coils 7A and 7B for heating are tubular containers T during heating.
Since it is necessary to sandwich and press, a strong resin such as bakelite or epoxy resin is molded to form a chuck head.

Next, one embodiment of the method of the present invention using the tubular container sealing device having the above-mentioned structure will be described with reference to FIGS.
Will be described with reference to.

(1) When the carry-in device B conveys the tubular container T while rotating it clockwise as shown in FIG. 4 (A), it rotates counterclockwise in synchronization with the rotary table 1. While the holder 2 gradually rises, it receives the tubular container T and continues to rise further, and approaches the pair of crimping tools 9A and 9B located above it. When the holder 2 reaches the rising end, the rod 10 for the crimping tool 9B is advanced, and as shown in FIG. 4B, the pair of crimping tools 9A and 9B are closed to open the tubular container T. Hold it while pressing the edge.

(2) When the pair of crimping tools 9A and 9B continue to rotate and reach below the primary coil 3 as shown in FIG. 5, the secondary coil 6 is generated by the high frequency electromagnetic induction of the primary coil 3. To generate high-frequency currents, and also generate high-frequency currents (in the same direction) in the tertiary coils 7A and 7B built in the crimping tools 9A and 9B. The metal foil forming the tubular container T sandwiched between the crimping tools 9A and 9B is subjected to high frequency induction heating by the high frequency current (in the same direction) of the tertiary coils 7A and 7B. By the heating, the resin laminated on the metal foil is melted, and the ends of the tubular container T pressed and sandwiched by the pressure bonding tools 9A and 9B are pressure bonded via the molten resin. This crimping is performed while the crimping tools 9A and 9B pass under the primary coil 3 as shown in FIG. 5, and when passing through the primary coil 3, the high-frequency currents of the secondary coil 6 and the tertiary coils 7A and 7B are passed. Disappears and the high frequency induction heating by the crimping tools 9A and 9B is interrupted.

(3) On the other hand, while the crimping tools 9A and 9B convey the tubular container T toward the unloading device C as shown in FIG. 6A, the crimping tools 9A and 9B circulate in the tertiary coils 7A and 7B. With the cooling medium, the pressure-bonded portion of the tubular container T is cooled,
The resin of the crimping part solidifies and sealing is completed, and the crimping tools 9A, 9
When B reaches the carry-out device C, the rod 10 for the crimping tool 9B is retracted, as shown in FIG.
B is opened to release the tubular container T, and the tubular container T is handed over to the carry-out device C. The emptied holder 2 continues to rotate as described above.

In the above embodiment, the tube-shaped container T held by one holder 2 has been described, but a plurality of containers are arranged below the rotary table 1 at equal intervals along the periphery thereof. The tubular containers T are sequentially delivered to the holder 2 and the above-mentioned sealing operation is continuously performed.

That is, according to the method of the present invention using the apparatus A of the embodiment, the tubular container T can be continuously and reliably sealed while moving.

The operation of this embodiment will be described below. The energization direction of each of the tertiary coils 7A and 7B provided on each of the pair of crimping tools 9A and 9B that configure the pressurizing device 9 is shown in FIG.
By setting them in the same direction as shown in (B),
The sealing portion of the tubular container T is made concave in the width direction of the container (FIG. 8 (B)), and a stable sealed state can be formed in which the sealing portion is difficult to separate from both side edges of the container. That is, in the tubular container T formed by flattening the annular sheet, even when a restoring habit of restoring the annular shape acts on both side edges of the container, the pressure bonding width of the both side edges of the container is different from that of the other middle portion in the width direction of the container. Since it is larger than that in the above, the both side edge portions of the container can sufficiently endure the above-mentioned restoring behavior to the annular shape and are difficult to peel off.

A pair of crimping tools 9 constituting the pressurizing device 9.
By setting the energization directions of the respective tertiary coils 7A and 7B provided in A and 9B in the same direction as shown in FIG. 7 (B), a required crimping state to the sealing portion of the tubular container T ( Power consumption required to obtain a constant seal strength),
Alternatively, the heating time can be shortened and the productivity can be improved.

FIG. 13 shows the experimental results of the method of the present invention in comparison with the conventional method. By carrying out the method of the present invention, (a) the appearance of the sealing part is concave in the width direction of the container,
(b) The output used by the high frequency power source should be significantly reduced, (c)
It was confirmed that the heating time by the pressurizing device was drastically shortened, (d) the cooling time after heating was equivalent to that of the conventional method, and (e) higher sealing strength could be secured compared to the conventional method. It is recognized that the method of the invention provides excellent sealing property and productivity as a whole.

[0054]

As described above, according to the present invention, the tubular container can be reliably sealed and the productivity thereof can be improved.

[Brief description of drawings]

FIG. 1 is a schematic diagram showing an overall configuration of an embodiment of a sealing device.

FIG. 2 is an enlarged view of a main part of FIG.

FIG. 3 is a cross-sectional view of an essential part of FIG.

FIG. 4 is a schematic diagram showing a loaded state of a tubular container.

FIG. 5 is a schematic diagram showing a thermocompression bonding state of a tubular container.

FIG. 6 is a schematic view showing a carried-out state of a tubular container.

FIG. 7 is a schematic diagram showing a coil connection structure of a heating device.

FIG. 8 is a schematic view showing a form of a sealing portion of a tubular container.

FIG. 9 is a schematic view showing a coil energization direction of the pressurizing device.

FIG. 10 is a diagram showing a container width direction position of a tubular container and a scalar potential.

FIG. 11 is a schematic diagram showing a heat energy distribution in the sealing portion of the tubular container.

FIG. 12 is a schematic diagram showing a magnetic field that strikes a sealing portion of a tubular container.

FIG. 13 is a chart showing the effect of the method of the present invention.

[Explanation of symbols]

 T tube-shaped container 3 primary coil 5 high frequency oscillator 6 secondary coil 7A, 7B tertiary coil 9 pressurizing device 9A, 9B crimping tool

Claims (3)

[Claims] 1. When a tubular container laminated with a metal foil is heated and sealed by high frequency induction heating,
A high frequency current is supplied to the primary coil by a high frequency oscillator and the secondary coil is moved with respect to the primary coil to
While the secondary coil is approaching the primary coil,
A high frequency current is generated in the secondary coil by electromagnetic induction of the secondary coil, and a high frequency current is generated in the tertiary coil of a pressurizing device including a tertiary coil connected to the secondary coil to apply the pressure. In the method for sealing a tubular container, wherein the tubular container sandwiched by the device is subjected to high-frequency induction heating and pressure-bonded by the pressurizing device, and the tube-shaped container is sealed by a tertiary device provided in each of a pair of crimping tools constituting the pressurizing device. A method for sealing a tubular container, characterized in that the energization directions of the coils are set in the same direction. 2. The method for sealing a tubular container according to claim 1, wherein the tubular container comprises a heat-fusible material inside a metal foil. 3. When a tubular container laminated with a metal foil is heated and sealed by high frequency induction heating, a primary coil fixedly installed and connected to a high frequency oscillator and a movable primary coil can be moved toward and away from the primary coil. , A high frequency current is generated by electromagnetic induction from the primary coil when approaching 2
A secondary coil, a tertiary coil connected to the secondary coil, through which the high-frequency current flows, and a pressurizing device that includes the tertiary coil and performs high-frequency induction heating to crimp and seal the tubular container by the high-frequency current. In a device for sealing a tubular container comprising, a pressurizing device comprises a pair of crimping tools,
A tertiary coil is provided in each of the pair of crimping tools, and the third coil is energized in the same direction.
A tubular container sealing device comprising a secondary coil and respective tertiary coils connected to each other.