JP2004050604A - Heater for preform having cooling mechanism - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent overheating of a preform in a preform-heating apparatus of a mass production type which simultaneously heats a plurality of lines and to save the space required for the apparatus. <P>SOLUTION: A heating conveyor mechanism 20 having two lines of conveyor routes simultaneously conveying two lines of preforms P; heating mechanisms 40 respectively having a plurality of infrared heaters 42 arranged in two lines in parallel with the conveyor route outside the conveyor routes in the axial direction of the preform P; a blowing means; and a cooling mechanism 50 having a cooling box 53 arranged between two lines of the conveyor routes, are provided. The cooling box 53 has an air introducing opening 57 for introducing air from the blowing means and an outlet hole 56 for blowing out air to the preforms P conveyed on the two lines of the routes. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a preform heating device used for a blow molding machine for performing blow molding after heating an injection-molded or extruded preform, and in particular, a preform provided with a cooling mechanism for cooling a surface of the preform. A heating device.
[0002]
BACKGROUND ART AND PROBLEMS TO BE SOLVED BY THE INVENTION
A stretch blow molding apparatus previously proposed by the present applicant is described in JP-A-2001-88205.
[0003]
This stretch blow molding apparatus is a so-called mass-produced heat-resistant container molding machine, in which a plurality of rows of preform heating steps are performed simultaneously, and simultaneously heated preform groups are stretch-blown molded.
[0004]
In a stretch blow molding apparatus for heating a plurality of rows of preforms at the same time, the heating and conveying path tends to be long due to the necessity of sufficient heating time. However, an increase in the length of the heating transport path causes an increase in the installation area of the entire stretch blow molding apparatus in a factory. Particularly in a stretch blow molding apparatus for molding a heat-resistant container, since the preform is relatively thick, if the length of the heating conveyance path is limited, the heater output of the heating apparatus is increased to shorten the time. When the preform temperature is heated to an appropriate temperature for stretching, the surface of the preform is overheated and crystallized, so that the heating time must be increased to cope with the problem. Prolonging the heating time leads to prolonging the entire molding cycle, which is not particularly preferable in a mass-production type molding machine.
[0005]
Further, for a preform conveyed in two rows, an infrared heater is arranged outside the two rows of conveyance paths, and a heat insulating plate is arranged between the two rows of conveyance paths. In such a device, even if the heating time is taken to some extent, in the case of a thick preform, the temperature difference between the inner surface and the outer surface of the preform is large, and depending on the molding conditions, the inner temperature is too low, The obtained container became pearl-like and sometimes impaired the appearance.
[0006]
Further, a stretch blow molding apparatus having a preform heating apparatus previously proposed by the present applicant is described in JP-A-11-188785.
[0007]
In this preform heating device, a heating box is arranged on a side of a conveyance path of a preform conveyed in a single row, and cooling air blowing means is arranged on a side opposite to the heating box across the conveyance path of the preform. ing.
[0008]
According to this preform heating device, the cooling air blowing means appropriately sets the blowing position of the cooling air blowing nozzle, and blows the cooling air adjusted by the blowing amount adjusting means to the preform, thereby partially converting the preform. Cooling results in a large change in temperature distribution that cannot be obtained with an infrared heater alone. Further, in this heating device, a blower is provided in order to prevent overheating of the preform. However, this only prevents an excessive increase in atmospheric heat in the heating device. In particular, since the blower is located very close to the infrared heater, the air temperature before blowing is relatively high, and since the air blown by the blower passes between the infrared heaters, the cooling efficiency of the preform was poor. .
[0009]
An object of the present invention is to prevent overheating of a preform in a mass-produced preform heating device for heating a plurality of rows at the same time, and to realize space saving of the device.
[0010]
It is another object of the present invention to provide a preform heating device that does not increase the cycle time of the entire apparatus by increasing the heating time even in a mass production type stretch blow molding machine.
[0011]
Still another object of the present invention is to provide a heating device for a preform in which, when the preform is thick, the molded container does not crystallize and become cloudy even when the heater output of the heating device is increased. It is in.
[0012]
[Means for Solving the Problems]
In order to achieve the above object, a preform heating device of the present invention is provided with a transport mechanism having two rows of transport paths for simultaneously transporting two rows of preforms, and outside the two rows of transport paths, A heating mechanism having a plurality of infrared heaters arranged in two rows in parallel with each transport path in the axial direction of the preform, a blowing means, and two rows of preforms transported through the two rows of transport paths; A cooling mechanism having cooling air blowing means disposed therein, wherein the cooling air blowing means supplies air to the preform conveyed through the two rows of conveying paths and an air inlet for taking in air from the blowing means. And a blowing hole for blowing.
[0013]
According to the present invention, since the cooling air blowing means of the cooling mechanism is arranged in the space conventionally separated by the heat insulating plate between the two rows of transport paths, the preform can be cooled without increasing the installation space.
[0014]
Further, since the cooling air blowing means is provided with an air blowing hole and blows air, the cooling air blowing means itself is not overheated by the heating mechanism, and the heat insulating plate is not required.
[0015]
Furthermore, since the cooling air blowing means is not built in the heating mechanism, it is not heated by the heater to generate hot air, and even a thick preform can be efficiently preformed by blowing cold air. The surface can be cooled.
[0016]
In the present invention, the transport mechanism transports the preform intermittently, and the cooling air blowing unit is a box type having two flat portions on the transport path side of the preform, and the two flat portions are The outlet may be provided so as to face a plurality of stop positions of the preform intermittently conveyed.
[0017]
As described above, the cooling air blowing means has a simple structure in which the cooling air blowing means has a box shape having a flat surface portion and has a blowing hole facing the stop position of the preform on the flat surface portion. The cooling air can be blown out from the blowing holes provided at a plurality of locations of the section to cool the preform at the stop position.
[0018]
In the present invention, the inside of the box-shaped cooling air blowing means can be maintained at a positive pressure by the introduced air.
[0019]
By maintaining the inside of the cooling air blowing means at a positive pressure, it is possible to blow constant air without bias from the blowing holes provided at the plurality of preform stop positions. Absent.
[0020]
In the present invention, the blowing means can be arranged in an atmosphere of less than 40 ° C. By arranging the blowing means in an atmosphere of less than 40 ° C., the temperature of the introduced air is reduced, the surface of the preform can be efficiently cooled, and the preform temperature can be stabilized.
[0021]
In the present invention, the flat portion may be in a mirror state. When the flat portion is in a mirror surface state, the light from the infrared heater is reflected to act as a reflection plate, and the preform can be efficiently heated.
[0022]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings.
[0023]
1 to 4 are views showing a biaxial stretch blow molding apparatus 1 using a preform heating apparatus according to one embodiment of the present invention.
[0024]
FIG. 1 is a plan view showing the entire configuration of the biaxial stretch blow molding apparatus 1, and FIG. 2 is a side view thereof. The biaxial stretch blow molding apparatus 1 shown in FIGS. 1 and 2 includes a supply unit 3, a heating unit 4, a transfer unit 5, a primary blow molding unit 6, a primary heat treatment unit 7, and a secondary heat treatment unit 8 on a machine base 2. This is an apparatus for molding a mass-produced heat-resistant container having two sets each of a final blow molding section 9 and a take-out section 10. The primary blow molding section 6, the primary heat treatment section 7, and the final blow molding section 9 have mold clamping mechanisms 11, 12, and 13, respectively, for clamping a split blow mold.
[0025]
In the biaxial stretch blow molding apparatus 1 shown in FIG. 1, two units are arranged at the top and bottom of the figure, but since the basic configuration and operation are the same, the following description will focus on the lower half.
[0026]
The preform P supplied by the supply unit 3 is transferred to the heating and transporting mechanism 20 of the heating unit 4, and is intermittently transported in six rows along the transport direction A in FIG. The preforms P that have passed through the heating unit 4 are transferred to the blow transport mechanism 30 while simultaneously changing the direction in which the preforms P are arranged 90 degrees at the transfer unit 5. The six preforms P delivered to the blow transport mechanism 30 are transported intermittently to the primary blow molding unit 6, the primary heat treatment unit 7, the secondary heat treatment unit 8, and the final blow molding unit 9, and every six preforms P The molding is performed in each part. In particular, in the primary blow molding section 6, biaxial stretching blow molding is performed by stretching the preform P in the longitudinal direction and blow molding in the lateral direction. The container carried out from the final blow molding section 9 to the take-out section 10 is discharged from the biaxial stretch blow molding apparatus 1 to the outside of the apparatus at the take-out section 10.
[0027]
The heating unit 4 includes a heating and transport mechanism 20 for transporting the preform P through six rows of transport paths, a heating mechanism 40 for heating the preform P, and a cooling mechanism 50 for cooling the surface of the preform P.
[0028]
As shown in the upper part of FIG. 1 (the heating part 4 in the upper part of FIG. 1 omits the heating mechanism 40 and the cooling mechanism 50 so that the conveying state of the preform P can be understood), A plurality of (16 in the present embodiment) heating and transport pallets 21 that rotatably hold six preforms P are arranged adjacently in the transport direction A, and the heated and transport pallets 21 are supplied below the outward routes. There is a return path to return to the section 3. The heated transport pallet 21 is intermittently transported in the transport direction A by a width of one heated transport pallet 21 by pushing the heated transport pallet 21 adjacent to the supply unit 3 by a driving unit (not shown).
[0029]
As shown in FIG. 4, by making the width L of the heating and transporting pallet 21 as short as possible, many preforms P can be simultaneously arranged in the heating unit 4, so that the outward path of the heating unit 4 is unnecessarily long. Without this, a sufficient heating time can be secured.
[0030]
The heating / transporting pallet 21 has both ends guided by guide rails 22 (see FIG. 3), a holder 23 for supporting the mouths of the six preforms P on the upper surface, and a sprocket for rotating each holder 23 on the lower surface. 24 (see FIG. 3). The sprocket 24 transmits the driving force of a rotation motor (not shown) by a belt, and rotates the preform in the heating unit together with the holder 23. By rotating the preform, the light from the infrared heater can be evenly applied in the circumferential direction.
[0031]
As shown in FIG. 3, the heating mechanism 40 has a heating box 41 fixed so as to be suspended from the frame 14 fixed to the machine base. The preform P side of the heating box 41 is largely open, and eleven infrared heaters 42 having both ends fixed to the heating box 41 are arranged side by side in the axial direction of the preform P. The heating box 41 of the present embodiment can simultaneously heat, for example, six preforms P along the transport direction A, and as shown in FIG. 1, two heating boxes 41 are arranged in each row. ing.
[0032]
The cooling mechanism 50 includes a blowing unit and a cooling air blowing unit. In the present embodiment, as shown in FIG. 2, six sirocco fans 51 are arranged on the frame 14 above the supply unit 3 as blowing means, and cold air is piped to the cooling air blowing means, for example, a flexible hose. It is sent at 52. Since the air blowing means needs to efficiently send air to the heating unit 4, it is preferable to provide the air blowing means adjacent to the heating unit 4. However, if the temperature of the air taken into the air blowing means is high, a sufficient effect as cooling air is exhibited. Can not. Therefore, in the present embodiment, as shown in FIG. 2, the blowing means is arranged not on the heating unit 4 but on the supply unit 3. Further, as a result of the experiment, the temperature of the air taken into the blowing means is preferably lower than 40 ° C., and according to the test, particularly preferable results can be obtained at 35 ° C. or less, In the test, the temperature of the preform P was not stabilized, and the molding was also adversely affected. In the present embodiment, since the sirocco fan 51 is used as the blowing means, the air taken in is the ambient temperature around the sirocco fan 51 (the temperature of the air-conditioned room). In order to stabilize the air conditioner, a dehumidifier or an air conditioner whose temperature can be set for the blowing means may be used.
[0033]
As shown in FIG. 3, the cooling air blowing means is constituted by a substantially rectangular parallelepiped cooling box 53 suspended from a frame 14 erected on a machine base. The transport path of the present embodiment has three sets (six rows) using two rows as a basic unit. Heating boxes 41 are arranged on both outer sides of the two rows of transport paths, and a cooling box 53 is provided between the two rows of transport paths. Are arranged opposite to each other with the conveyance path of the preform P interposed therebetween. As shown in FIG. 3, the heating boxes 41 arranged on the second and third transport paths and the fourth and fifth transport paths are arranged back to back.
[0034]
As shown in FIG. 4, the cooling box 53 is long in the transport direction A and has two flat portions 54 opposed to two rows of transport paths. Each flat portion 54 has six preforms P The blowout holes 55 are provided at six locations, respectively, corresponding to the transport stop positions. The blowing holes 55 at each stop position are formed by arranging a large number of holes formed along the axial direction of the preform P in two to four rows (in the present embodiment, ten holes 56 are shifted in height by four rows). ), And is formed in a range higher than the overall height of the preform P and wider than the diameter of the preform P so that the cooling air is evenly applied to the entire stopped preform P. Further, the heating box 41 is made of stainless steel, the flat portion 54 is in a mirror surface state, and also has a function as a reflection plate on a surface facing the infrared heater 42.
[0035]
A flexible hose 52 having the other end connected to the sirocco fan 51 is connected to an air inlet 57 on the upper surface of the cooling box 53, and cooling air is sent from the sirocco fan 51. This cooling air is blown onto the surface of the preform P being heated from the blowing holes 55 provided in the flat portion 54 of the cooling box 53 to cool the surface of the preform P overheated by the infrared heater 42. . At this time, the inside of the cooling box 53 is always maintained at a positive pressure by controlling the amount of air sent from the sirocco fan 51 to be larger than the amount of air discharged from the blowout holes 55. By maintaining the inside of the cooling box 53 at a positive pressure, air is blown out from the blowout holes 55 provided at six locations without bias.
[0036]
Therefore, in the apparatus of the present embodiment, the six preforms P delivered from the supply unit 3 to the heating unit 4 are arranged along the transport path while being transported in two rows and three sets (six rows). And the outer surface of the preform P is efficiently cooled by the cooling air blown out from the cooling box 53 arranged between the two rows of the conveying paths, while being efficiently heated by the infrared heater 42 of the heated heating box 41. Can be. By cooling the outer surface of the preform P, the temperature difference between the inner surface and the outer surface of the preform P can be reduced even when a relatively thick preform P is formed.
[0037]
As described above, according to the present embodiment, in a mass-production type apparatus for heating a plurality of rows of preforms, the heating and conveying path can be designed to be compact, and the space-saving design of the apparatus becomes possible. Further, even if the preform is heated in a short time, there is no overheating of the preform surface, so that the cycle time can be shortened. Furthermore, even when heating a relatively thick preform, a transparent container can be obtained without crystallization even when the heater output is increased.
[0038]
It should be noted that the present invention is not limited to the present embodiment, but can be modified into various forms within the scope of the present invention.
[0039]
For example, in the above-described embodiment, a so-called two-stage reheat blow molding machine that receives a preform in the supply unit 3 is used. There may be.
[0040]
Further, the infrared heater 42 may be a near infrared heater or a far infrared heater. It is known that commercially available infrared heaters can generally select a heater having a wavelength suitable for heating the material depending on the material to be heated.
[0041]
In addition, the blowing hole may be formed so that the cooling air can be blown to the outer surface of the preform as uniformly as possible.
[Brief description of the drawings]
FIG. 1 is a plan view showing the overall configuration of a heat-resistant container forming apparatus using a preform heating apparatus according to one embodiment of the present invention.
FIG. 2 is a side view of the heat-resistant container forming apparatus of FIG.
FIG. 3 is a sectional view taken along line XX of the heating unit in FIG. 1;
FIG. 4 is a side view of a cooling box and a preform conveyance path.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Biaxial stretch blow molding apparatus 2 Machine base 3 Supply part 4 Heating part 5 Transfer part 6 Primary blow molding part 7 Primary heat treatment part 8 Secondary heat treatment part 9 Final blow molding part 10 Extraction part 40 Heating mechanism 41 Heating box 50 Cooling mechanism 51 Sirocco fan 53 Cooling box 54 Flat part 55 Blow-out hole 57 Air inlet

Claims (5)

In the preform heating device,
A transport mechanism having two rows of transport paths for simultaneously transporting two rows of preforms;
A heating mechanism having a plurality of infrared heaters arranged outside the two rows of transport paths and arranged in two rows in parallel with the respective transport paths in the axial direction of the preform;
Blowing means,
A cooling mechanism having cooling air blowing means disposed between the two rows of preforms transported on the two rows of transport paths;
Has,
The cooling air blowing means has an air inlet for taking in air from the blowing means, and a blowing hole for blowing air to a preform conveyed through two rows of conveying paths. Reform heating device. In claim 1,
The transport mechanism transports the preform intermittently,
The cooling air blowing unit has a box shape having two flat portions on the side of the preform conveyance path,
The preform heating device, wherein the two plane portions have the blowout holes facing a plurality of stop positions of the preform conveyed intermittently. In claim 2,
A preform heating device, wherein the inside of the box-shaped cooling air blowing means is maintained at a positive pressure by introduced air. In claim 1,
An apparatus for heating a preform, wherein said blowing means is disposed in an atmosphere of less than 40 ° C. In claim 2,
The preform heating device, wherein the flat portion is in a mirror surface state.

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