METHOD AND APPARATUS FOR TEMPERING THE NECK END REGION OF MOLDED PREFORMS

Abstract

An apparatus for cooling molded preforms may comprise a conveyor device for conveying the molded preforms and a tempering insert. The conveyor device may also comprise an extraction plate that contains a cooling cavity for receiving and cooling a closed section of a molded preform. The tempering insert may be connected to the conveyor device and be configured to temper a neck region of the preform by direct contact. The tempering insert may be designed to both temper and accommodate a preform in the conveyor device. The apparatus may further comprise a heat pipe that is configured to draw heat from the cooling cavity to cool the closed section of the preform.

Claims

1. An apparatus for cooling molded preforms (2, 422, 502, 622, 702) comprising: a conveyor device (30, 34, 36, 38, 500, 530, 650, 730) for conveying the molded preforms (2, 422, 502, 622, 702); the conveyor device comprising at least one extraction plate (30, 530, 730, 730A) having at least one cooling cavity (32, 533, 733) for receiving and cooling a closed section (4, 704) of a molded preform (2, 422, 502, 622, 702); at least one tempering insert (560, 660, 760) connected to the conveyor device (30, 34, 36, 38, 500, 530, 650, 730) for tempering a neck region (8, 508, 608, 708) of the preform by direct contact; and the at least one tempering insert (560, 660, 760) is designed to both temper as well as accommodate a preform (2, 422, 502, 622, 702) in the conveyor device (30, 34, 36, 38, 500, 530, 650, 730).

2. An apparatus for cooling molded preforms (2, 422, 502, 622, 702) comprising: a conveyor device (30, 34, 36, 38, 500, 530, 650, 730) for conveying the molded preforms (2, 422, 502, 622, 702); the conveyor device (30, 34, 36, 38, 500, 530, 650, 730) comprising at least one extraction plate (30, 530, 730, 730A) having at least one cooling cavity (32, 533, 733) for receiving and cooling a closed section (4, 704) of a molded preform (2, 422, 502, 622, 702); at least one tempering insert (560, 660, 760) connected to the conveyor device (30, 34, 36, 38, 500, 530, 650, 730) for tempering a neck region (8, 508, 608, 708) of the preform by direct contact; and at least one heat pipe (770, 770A) able to draw heat from the cooling cavity (32, 533, 733) to cool the closed section (4, 704) of the preform.

3. The apparatus for cooling molded preforms according to claim 1, characterized in that the tempering insert (560, 660, 760) corresponds to the shape of the threaded neck region (8, 508, 608, 708) of the preform (2, 422, 502, 622, 702).

4. The apparatus for cooling molded preforms according to claim 1, characterized in that the tempering insert (560, 660, 760) for tempering the neck region (8, 508, 608, 708) of the preform (2, 422, 502, 622, 702) is connected to an ejection device (564, 764).

5. The apparatus for cooling molded preforms according to claim 1, characterized in that the tempering insert (560, 660, 760) of the apparatus can be used only to cool or only to heat or both to cool as well as heat the neck region (8, 508, 608, 708) of the preform (2, 422, 502, 622, 702).

6. The apparatus for cooling molded preforms according to claim 2, characterized in that the at least one heat pipe (770, 770A) is connected to a heat dissipation area (780, 780A, 781).

7. The apparatus for cooling molded preforms according to claim 6, characterized in that the heat dissipation area (780, 780A, 781) has a large surface, particularly cooling fins.

8. The apparatus for cooling molded preforms according to claim 6, characterized in that the apparatus comprises a ventilator device (790) which produces a flow of air in the area of the heat dissipation area (780, 781) connected to at least one heat pipe (770),

9. The apparatus for cooling molded preforms according to claim 1, characterized in that the at least one tempering insert (560, 660, 760) can be brought into an eject position to eject the preform (2, 422, 502, 622, 702) from the conveyor device (30, 34, 36, 38, 500, 530, 650, 730) at which the preform is released from the tempering insert (560, 660, 760) in its open position.

10. A method for cooling molded preforms with an apparatus according to claim 1 comprising the following steps: injection molding a preform (2, 422, 502, 622, 702); removing the molded preform from a mold core; transferring the preform to a conveyor device (30, 34, 36, 38, 500, 530, 650, 730); and cooling a closed section (4, 704) of the preform and simultaneously tempering a neck region (8, 508, 608, 708) of the preform by direct contact with at least one tempering insert (560, 660, 760) in the conveyor device.

11. The apparatus for cooling molded preforms according to claim 2, characterized in that the tempering insert (560, 660, 760) corresponds to the shape of the threaded neck region (8, 508, 608, 708) of the preform (2, 422, 502, 622, 702).

12. The apparatus for cooling molded preforms according to claim 2, characterized in that the tempering insert (560, 660, 760) for tempering the neck region (8, 508, 608, 708) of the preform (2, 422, 502, 622, 702) is connected to an ejection device (564, 764).

13. The apparatus for cooling molded preforms according to claim 2, characterized in that the tempering insert (560, 660, 760) of the apparatus can be used only to cool or only to heat or both to cool as well as heat the neck region (8, 508, 608, 708) of the preform (2, 422, 502, 622, 702).

14. The apparatus for cooling molded preforms according to claim 2, characterized in that the at least one tempering insert (560, 660, 760) can be brought into an eject position to eject the preform (2, 422, 502, 622, 702) from the conveyor device (30, 34, 36, 38, 500, 530, 650, 730) at which the preform in an open position.

15. A method for cooling molded preforms with an apparatus according to claim 2 comprising the following steps: injection molding a preform (2, 422, 502, 622, 702); removing the molded preform from a mold core; transferring the preform to a conveyor device (30, 34, 36, 38, 500, 530, 650, 730); and cooling a closed section (4, 704) of the preform and simultaneously tempering a neck region (8, 508, 608, 708) of the preform by direct contact with at least one tempering insert (560, 660, 760) in the conveyor device.

Description

[0034] Further advantages, features and possible applications of the present invention are indicated in the following description in conjunction with the figures.

[0035] Shown are:

[0036] FIG. 1: a preform to be subsequently blow molded;

[0037] FIG. 1A: a known PET preform for bottles;

[0038] FIG. 1B: a further known PET preform for bottles;

[0039] FIG. 2: a side view of one embodiment of the invention;

[0040] FIG. 3: a perspective view of a further embodiment of the invention;

[0041] FIG. 4: a perspective view of a further embodiment of the invention;

[0042] FIG. 5, 5A, 58, 5C sectional views of a further embodiment of the invention;

[0043] FIG. 6, 6A, 6B sectional views of a further embodiment of the invention;

[0044] FIG. 7: sectional view of a further embodiment of the invention;

[0045] FIG. 7A: sectional view of a further embodiment of the invention; and

[0046] An injection molding and cooling apparatus for hollow blow-moldable preforms uses tempering inserts which in terms of their design, correspond to the threaded neck end of the preform. The tempering inserts are coupled to an extraction plate, an extraction frame or other similar preform conveyor device which indirectly or directly collects the freshly molded preforms from the mold cores used to manufacture said preforms. The tempering inserts can cool or heat the neck end. These tempering inserts are connected to cooling tubes or cooling cores arranged external of the mold cavities and serve to cool the rest of the preform not provided with a thread. The tempering inserts can be connected to an ejection mechanism which enables removal of the preforms from the cooling tubes/cooling cavities or the cooling cores.

[0047] FIG. 1 shows a blow-moldable preform 2 having a closed body section 4, a dome-shaped region 6 and a neck region 8 provided with a thread.

[0048] The threaded neck region 8 must be shaped as precisely as possible, as shown in the known preforms of FIGS. 1A and 1B. The threaded neck ends of these two preforms exhibit the same dimensions but the FIG. 1A preform is lighter than the FIG. 1B preform and also has a thinner wall in closed body section 4.

[0049] A higher output of molded preforms from the same mold allows higher yields using the same equipment. One possible option for increasing the output is to reduce the cycle time for the post-injection cooling and the extraction of the preform 2 (not shown in FIG. 2) from the mold halves 16 to 22 (not shown in FIG. 2). In the present embodiment of the invention, the preforms 2 are extracted from the mold cores 22 and immediately transferred to the extraction plate/frame 30 which is brought between the mold halves 16, 20 via the actuating means 34, 36, 38. The extraction plate/frame 30 has an array or matrix of cooling tubes or cooling cavities 32 respectively, wherein the cooling cavities are formed in cooling tubes in the present embodiment.

[0050] The extraction plate/frame 30 is depicted in greater cross-sectional detail in FIGS. 5 to 5C. FIG. 5 depicts the extraction plate 30 as extraction plate 530 and a portion of the extraction arrangement 500. Cooling cavities 533 are disposed in the extraction plate 530, in the immediate vicinity of which cooling channels 562 are arranged through which a coolant such as e.g. cooling water flows to cool the cooling cavity 533. The coolant thereby has a distinctly clearly lower temperature than a preform 508 to be cooled.

[0051] In this arrangement, the cooling cavities 533 are empty and thereby ready to directly receive the preforms 502 from the injection cores 22 of FIG. 2 or from the cores 122 as shown in FIG. 3. The extraction plate 530 further comprises tempering inserts 560 which in the present embodiment are formed by two movable mirror-image inserts 560′ and 560″. The inserts 560′ and 560″ exhibit a threaded region 561 formed on the tempering inserts 560′ and 560″ as regions 561′ and 561″ so as to establish a good contact with the neck region of the preform 2. Temperature control channels 563 are formed in the tempering inserts 560 through which a temperature control liquid such as e.g. water flows to regulate the temperature of the tempering inserts. For cooling the preforms, the temperature control liquid thereby has a distinctly clearly lower temperature and for heating the preforms, a distinctly clearly higher temperature than the threaded region of the preform 508.

[0052] The extraction plate 530 also comprises a preform ejection device 564 having ejecting rods 568 movable along the cooling cavities 533. In FIG. 5, the inserts 560′ and 560″ are in a first open position which allows the preforms to enter into the cooling tube. As shown in FIGS. 5B and 5C, as soon as the preforms are in the cooling cavities 533, the tempering inserts 560 move into a closed position in which there is direct contact 565 with the threaded neck end 508 of the preform 502.

[0053] Depending on the application, the length of the process and the purpose of the preform 502, the tempering inserts 560 are used to further cool or heat the neck end 508 of the preforms 502. Heating is less common albeit essential to crystallizing the neck region 508 externally of the mold.

[0054] As FIG. 5C shows, as soon as they have sufficiently cooled, the preforms are ejected by the ejecting rods 568 of the preform ejection device 564. The ejecting rods 568 are actuated by actuator 566. The preforms separate from the inserts due to the sideways opening of the tempering inserts 560′ and 560″ effected by control cams (not shown) or by means of other mechanisms interacting with the ejecting rods.

[0055] It is just as possible for the preforms 2, 402 to be transferred to cooling cores 52, 422. Suitable cooling cores 52 are shown in FIG. 2 and equally suitable cooling cores 422 are shown in FIG. 4.

[0056] Such cooling cores 52 and 422 are shown in more detail in FIGS. 6, 6A and 6B, whereby the neck end 608 of the preform 622 is cooled or sometimes also heated using tempering inserts 660′ and 660″. The cooling cores 52, 422 are thereby arranged on a cooling core plate 50, 650 which can, depending on the design of the mold 16, 22, also assume the function of an extraction plate or to which the preforms 2, 402 are transferred from the extraction plate in a second conveying step. The cooling core plate 50, 650 is arranged in the immediate vicinity of the tempering inserts 660. In FIGS. 6 to 6B, a cooling element 652 is arranged on the cooling core plate 650 which ensures the dimensional stability of the preform 622 and transfers the cooling power from the cooling core 52, 422 to the preform 622.

[0057] FIGS. 6 to 6B shows how the tempering inserts 660, through which a tempering liquid flows in tempering channels 663, act as part of the conveyor device. In FIG. 6, the tempering inserts 660 are in an open position in order to receive the threaded neck end region 608 of the preform 622. In FIG. 6A, the tempering inserts 660 are in a closed position and thereby positively hold the preform 622 at its neck end region 608, keeping it on the cooling core plate 650. In FIG. 6B, the tempering inserts 660 move into an opened position in which the preforms 622 are no longer held on the cooling core plate 650 and can thus be removed from same. Combined with a further suitable ejection mechanism or with a suitable arrangement drawing on the effect of gravity acting on the weight of the preforms 622 themselves, the tempering inserts 660 thus also serve in ejecting the preforms from the cooling and/or conveyor device.

[0058] For the further conveying and cooling of the preforms, the cooling cavity 32 and the extraction plate 30 in the FIG. 2 embodiment are transferred out of the injection chamber defined between mold halves 16 and 20. For example, the preforms 2 can be transferred while accommodated within the cooling cavities 32 formed in the cooling tubes 32.

[0059] As FIG. 5 shows, temperature sensors 570, 572, such as for example thermocouples, are arranged at various positions on the extraction plate 530 in order to monitor the temperature of each preform or the temperature of the cooling cavities 533 or cooling inserts 560. This preform temperature information can be used to regulate injection molding parameters such as for example the temperature of the molten material exiting a hot runner nozzle system 18 disposed in mold half 16.

[0060] FIGS. 7 to 7B show a sectional view of a further embodiment of the invention. Cooling cavities 733 in which a preform 702 is accommodated are arranged in the extraction plate 730. Tempering inserts 760 are arranged on the extraction plate 730, each accommodating a preform 702 in substantially positive manner in the depicted closed position.

[0061] The tempering inserts 760 are connected to an ejection device 764 which is movable in the direction of the longitudinal axis of the preforms 702 by means of actuators 766 in order to move the preforms into or out of the cooling cavities 733. During the ejecting process, the ejection device 764 moves the preforms 702 out of the cooling cavities 733 by means of actuators 766. The tempering inserts 760 shown in the closed position then withdraw sideways from the neck end region 708 of the preforms into an open position in which the preforms 702 are no longer held and thus expelled.

[0062] Heat pipes 770 are arranged in the immediate vicinity of the cooling cavities 733 which run in the longitudinal direction of the preforms 702 along the closed section 704 and past the dome-shaped region 706 from the interior of the extraction plate 730 out into the open. The heat pipes 770 thereby consist of a material having higher thermal conductivity than the area of the extraction plate in which the cooling cavity 733 is formed. The heat pipes 770 thereby conduct thermal energy from the area in direct proximity to the cooling cavity 733 to the open area in which the temperature is lower than at the cooling cavity.

[0063] The heat pipes 770 are connected to a heat dissipation area 780, 781 having a large surface so as to be able to quickly release the thermal energy to the environment. The heat dissipation area 781 is formed directly on the heat pipe 770 and has an enlarged cross-sectional area compared to the other areas of the heat pipe. In order to increase the thermal output and thus the thermal energy able to be conducted out of the cooling cavity 733, the heat pipes 770 are connected to a further heat dissipation area 780 which comprises a plurality of heat sinks arranged in the manner of cooling fins. The heat sinks and thus heat dissipation area 780 have a large surface area and can thereby emit large amounts of heat to the environment, particularly without needing to expend additional energy in doing so.

[0064] FIG. 7A shows a further embodiment of heat pipes 770A comprising a heat dissipation area 780A. The design of extraction plate 730A, the cooling cavities 733A and the ejection device 764A along with tempering inserts 760A and actuators 766A correspond to that of the same elements shown in FIG. 7. The heat pipes 770A in this embodiment are arranged on a heat transfer element 772 disposed on the extraction plate 730A in the immediate vicinity of the cooling cavity near the dome-shaped region 706 of the preform 702.

[0065] In the embodiment of FIG. 7A, four heat pipes 770A run out from the heat transfer element 772 and extend in a direction away from the extraction plate 730A. On their opposite end from the heat transfer element 772, the heat pipes 770A are connected to a heat dissipation area 780A consisting of a plurality of heat sinks and thus likewise having a large surface area for conducting larger amounts of heat into the environment. In this embodiment, a plurality of heat pipes 770A are connected to heat dissipation area 780A, thereby improving the transfer of heat from the heat pipes 770A at a cavity to their heat dissipation area 780A.

[0066] FIG. 7B shows a further embodiment of the invention. The elements depicted in FIG. 7B correspond substantially to the elements depicted in FIG. 7 such that reference is made to the description of FIG. 7. In addition to the implementation as in FIG. 7, the embodiment of FIG. 7B comprises ventilator devices 790 which conduct a flow of air onto heat dissipation area 780 and 781 in order to accelerate the release of heat from the heat dissipation area 780 and 781 and thus increase the amount of heat released into the environment. The ventilator devices 790 are thus configured so that the dispensed airflow will pass over the largest possible surface area of the heat dissipation areas 780 and 781. The ventilator device 790 thus intensifies the cooling action of the at least one heat pipe 770 on the preform 702.