JPS59228387A - High frequency induction heating coil unit - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION More specifically, the present invention relates to a high frequency induction heating coil device for heating/heating the end of a flange portion of a cylindrical body such as a container body.

Conventionally, high-speed heating is used as a heating method when heat-sealing an end wing (i.e., a bottom part and/or a U, a lid part) containing a metal foil layer to a flange part of a cylindrical body such as a container body. The high frequency induction heating method, which has the advantage of being capable of cooling, has been widely adopted.

In this case, in order to prevent the high-frequency induction heating coil (hereinafter referred to as heating coil) from overheating and to increase the cooling rate after the heating coil is deenergized, that is, after heat sealing, the heating coil is usually represented and the inside is filled with cooling water. flows through, Fig. 1, Fig. 2
A water-cooled steel mother pipe 1 as shown in the figure is used.

In FIGS. 1 and 2, 2 is the container body, and 3 is the lid. The outer flange 2a of the container body 2 is joined to the peripheral edge 3a of the lid 3 by heat sealing. It will be done. Although not shown, the upper layer of the flange portion 2a is made of a heat-sealable resin (for example, polyolefin such as polyethylene), the lower layer of the lid member 3 is also made of a similar heat-sealable resin, and an adhesive layer is formed on the lower layer. A metal foil layer (for example, made of aluminum foil) is provided through the heating coil J, and when the heating coil J is energized, a magnetic flux 4 is induced and this metal foil layer is heated by high frequency induction. Heat sealing is performed by melting or softening the heat sealable resin.

In this case, the heating coil 1 has a water cooling hole 1a through which the water 5 flows and is relatively thick (for example, about 8 to 15 mm), so that
The magnetic flux 4 also passes through the inner vicinity portion 3b of the peripheral edge portion 3a of the lid member 3, which has a small heat capacity, and the heat/rollable resin in the lower layer of the inner vicinity portion 3b is likely to melt or soften. Therefore, contents 6
contains water, and a part of this content 6 is transferred to the Franz part 2.
If heat sealing is performed while it is attached to a,
Near inner side: A problem arises in that foaming is likely to occur between the lower layer of the lining and the metal foil layer.

When the resin is melted or softened, the permeability of water vapor increases rapidly, so when the resin is heated, water in the contents above the flange portion 2a turns into water vapor, and the melted or softened lower layer heat-sealable resin Fully transparent and inner near part 3biC
It is presumed that a foamed portion containing water vapor is generated between the lower layer and the metal foil layer, and that this foamed portion becomes a foamed portion containing water by cooling after heat sealing. This foamed part not only spoils the appearance, but if the content 6 contains acid, the water in the foamed part also becomes acidic, corroding the metal foil layer of the foamed part over time, and damaging the gas barrier of the lid part 3. Lose sex.

Furthermore, the heating coil 1 has both ends 11), ] c
- current and cooling water are supplied and sent through power feeders 7a and 7b, which are made of a copper wire similar to that of the heating coil body 1d and are separated from each other by a thin electrical insulation layer 8; It is done. In this case, at both ends lb and lc, due to the presence of the power feeders 7a and '7b, the magnetic flux 4 surrounding the no and eaves cannot be formed as in the main body 1d.
Therefore, during heat sealing, both ends 1'b, 1
The temperature rise due to induction heating of the lid part (portion 3aH of the secondary peripheral part 3a) facing the main body 1d
It is much smaller than the part of Therefore, incomplete heat sealing is likely to occur in the portion 3a1, and if the output is reduced in an attempt to prevent this, the portion of the peripheral portion 3a facing the main body 1d will overheat, leading to deterioration of the resin in the affected portion.
Problems such as a decrease in heat/roll strength are likely to occur.

The present invention aims to solve the problems of the prior art described above.

To achieve the above object, the present invention provides a high-frequency induction heating coil device for heat-sealing an end flange to a flange portion of a cylindrical body, the device comprising a ribbon-shaped high-frequency induction heating coil having a shape corresponding to the flange portion of the cylindrical body. A cooling hole is formed along the heating coil to guide the cooling liquid so that the cooling liquid flows in contact with the upper surface and/or side surface of the heating coil. The present invention provides a high frequency induction heating coil device characterized in that the vicinity of the cooling hole of the cooling liquid pipe for supplying and sending out liquid is electrically insulated.

The present invention will be described with reference to the drawings which are embodiments of the plate.

3, 4, 5, and 6, the high-frequency induction heating coil device II (hereinafter referred to as the heating coil device) has a flange portion to be heat-sealed to the peripheral edge 3a of the lid portion 3. 2a, a ribbon-shaped annular heating coil 12 having a shape corresponding to 2a, and a plurality of (11 pieces in the drawing) rectangular plate-shaped magnetic cores 13 made of an electrically insulating high permeability material (for example, ferrite) to increase magnetic flux density. , a support made of electrically insulating Rf-B (for example, Bakelite) with relatively high mechanical strength; Qmm) the bottom plate 15 and the heat-resistant elastic thin film 16 (
For example, it is equipped with non-contact rubber).

The magnetic cores 1; 3 are placed on the top surface of the heating coil 12, and the inner side
a and the outer end 13b are attached so as to slightly protrude from the heating coil 12, and a gap 17 is formed between each magnetic core 13. A central protrusion 14a is formed at the bottom of the support body 4, and its height is equal to that of the heating coil.
2 and the height of the magnetic core 13. The bottom plate I5 is attached to the bottom surface of the central protrusion 14a and the bottom surface of the heating coil 12. 4a1 and the inner end 13a of the magnetic core 13.
A circumferential hole 18 is defined between the two. The magnetic core 13 is located at the base 14a of the central protrusion 14a.
The lower surface of the periphery extending radially outwardly from both ends]/Ib. A cooling liquid 19 for cooling the heating coil 12 flows through the hole 18 and the gap 17, but a seal is provided to prevent this cold liquid 19 from flowing outward from the gap 7. A portion 20 (made of an adhesive such as epoxy resin, for example) is provided at the end of the gap 17.

The heating coil J2 is usually made of a copper ribbon with a thickness of about 0.5 to 2.0 mm, and its both ends 12a, 12bl-1: m thick (for example, 0.05 to 2.0 mm) are connected through two electrically insulating layers. Each end seen in isolation], 2a and 12bJ:
I) Heating coil 12 extending upwardly and having a circumferential thickness
The rising portions 22a and 22bt/i are approximately equal in thickness to
Respective power supply plates 23a and 23b [connect. Power supply plate 2
Feeders 24a screwed to 3a and 23b, respectively.
and 24b, a high frequency oscillator K (not shown)
Continue m.

Guide holes 25a are provided near both ends 1.8a and 18b of the hole 18.

25b is open, and the guide holes 25a and 25b are respectively a liquid supply pipe 26a and a delivery pipe 26b (the portions of these pipes near the heating coil device 11 are preferably formed of an electrically insulating material). The liquid supply pipe 26a is connected to a liquid supply source (for example, a water pipe), not shown. In addition, 27
This is the seal part.

The heating coil device 11 is moved up and down via a support rod 28 by a drive mechanism (not shown).

The thickness of the elastic thin film I6 is usually about 0.5 to 50 mm, preferably 1 to 3 mm, and there is a stepped portion (based on the side overlap joint of the container body 2; not shown) in the flannel portion 2a.
In such cases, the step part is provided to completely prevent the formation of pores after heating. In the case of a container body 2 having a flat flange portion 2a and a large stepped portion (for example, a cup-shaped container formed by vacuum forming a thermoplastic sheet), the elastic thin film 16 is not necessarily provided. You don't have to.

FIG. 5 shows how the heating coil device 11 is used to
This figure shows an example of heat sealing a and the lid member 3. The bottom phase 10 is heat-sealed to the container body 2 in advance to form a container body 4o, and the container body 40 is filled with the contents 6.

Reference numeral 30 denotes a support for supporting the pressing force during heating and heating, and when loading and unloading the container body 40, the half pieces 30a, 30b, etc. It opens outward along the support plate 32.

Heat sealing is performed as follows. First, place the peripheral edge 3a of the lid part on the flange part 2a, then place the flange part 2a on the support 30 with a slight amount of support 30 remaining, and then close the support 30. .

Next, the support rod 28 is lowered to lower the heating coil device 11 through which the cooling fluid 19 flows, and the flange portion 2 is lowered.
a and the peripheral edge 3a are pressed between the support 30 and the elastic thin film 6 with a predetermined pressing force? ff At the same time, the heating coil 12
energize. Due to this energization, a magnetic flux 33 is formed around the heating coil 12, the metal foil layer at the peripheral edge 3a is heated by induction, and the two layers of sealing resin, the lower layer of the peripheral edge 3a and the flange area, are melted. Alternatively, it is softened and subjected to heat treatment 7 to form a heat-sealed portion 4I.

In this case, the heating coil is 1.2 Vi rectangular and thin.
The magnetic flux 33 hardly passes through the radially inner side of the peripheral edge 3a of the lid part 3, so there is no risk of the heat-sealable resin in the inner side vicinity 3b melting or softening and forming a foamed part.

In addition, since the heating coil J2 is cooled by the cooling liquid 19, it will not be overheated even when a relatively large amount of power is applied to it.
= The cooling of the heat/ru part after de-energization is also fast, so heat-sealing work can be done in a very short time (e.g., heating time of 2 seconds or less, cooling time of 2 seconds or less during suppression release after de-energization). Become.

Furthermore, the end portion 18a of the hole portion 18 through which the cooling liquid 19 flows.

Since there is no copper pipe or the like having a relatively large width in the circumferential direction that prevents the formation of the magnetic flux 33 in the vicinity of the peripheral edge 3
At a substantially uniform temperature along the circumferential direction of the heating coil 12 (vertical J-nigged portions 22a, 22
Induction heating takes place (with the exception of a slight temperature drop based on b).

After heat-sealing, the heating coil J2 is deenergized, and after the resin in the heat-sealed part 41 is cooled and solidified, the heating coil device]1
to release the pressure.

The present invention is not limited to the above embodiments,
For example, as shown in FIG. 6, the bottom surfaces of both legs 53a of an annular magnetic core 53 having a U-shaped cross section are attached to the upper surface of the heating coil 52, and a cooling liquid is inserted into the circumferential hole 58 of the magnetic core 53. It may be a heating coil device 51 in which 9 flows through. In this case, the lower mj of the central protrusion 54a of the support 54 and the lower surface of the heating coil 52 are located on the same plane, and the bottom plate 15 of the heating coil device 11 is not required. In the case of the heating coil device 11, the contact between the heating coil 12 and the cooling liquid 19 is made at a portion along the circumferential direction of the inner/outer and upper surfaces of the heating coil 12 (the portion of the gap 17). In the case of the device 52, the heating is performed along the entire circumference of the upper surface of the heating coil 52.

Further, the present invention can be applied to heat sealing between a container body and a bottom, and heat sealing between a cylindrical body (including a cup-shaped body with a bottom) and an end member other than the container body.

According to the heating coil device of the present invention, it is possible to perform heat sealing at a substantially uniform heat sealing temperature along the flange portion, and to perform heat sealing on the end side in a very short time. At this time, it is possible to prevent foaming due to melting or softening of the heat-sealing resin near the end on the radially inner side of the heat-sealing portion.

[Brief explanation of drawings]

Figure 1 is a longitudinal sectional view of the main part showing heat sealing using a conventional high-frequency induction heating coil, Figure 2 is a cross-sectional view taken along the line ■-■ in Figure 1, and Figure 3 is A front view of the heating coil device according to the first embodiment of the present invention, FIG. 4 is a cross-sectional view taken along the line IV-IV in FIG. 3, and FIG. A vertical cross-sectional view of the heating coil device taken along the line ■-v in FIG. 45, showing a state in which sealing is performed; FIG. 6 is a vertical cross-sectional view taken along the line ■-■ in FIG. 3; FIG. 7 is a longitudinal sectional view of a heating coil device according to a second embodiment of the present invention. 2. Container body (cylindrical body), 2a. Flange portion, 3. Lid member (end side), 11.51... High frequency induction heating coil device, 12.52... High frequency induction heating coil, 17.・
Gap (cooling hole), 18... Circumferential hole (cooling hole), 19
- Cooling liquid, 25 a, 25 b = - conductor hole (cooling liquid pipe), 26a... liquid supply pipe (cooling liquid pipe), 26b delivery pipe (cooling liquid pipe), 58 - hole (cooling hole). Percentage applicant Akira Kishimoto

Claims (1)

[Claims] (]) A high-frequency induction heating coil device for heat-sealing an end member to a flange portion of a cylindrical body, the device includes a ribbon-shaped high-frequency induction heating coil having a shape corresponding to the flange portion, and the heating The top surface of the coil and/or
A cooling hole for guiding the cooling liquid is formed along the heating coil so that the cooling liquid flows in contact with the cut or side surface, and a cooling hole for supplying and discharging the cooling liquid to the cooling hole is formed. A high frequency induction heating coil device characterized in that a portion of a liquid pipe near a cooling hole is made of an electrically insulating material.