MOLD FILLING MACHINE AND MOLD FILLING METHOD FOR A PLASTIC CONTAINER

Abstract

Mold filling machine for molding a plastic container from a preform in a hollow mold and for filling the plastic container with product in the hollow mold, and with a valve head comprising a filling member for filling a product into the plastic container in the hollow mold, characterized in that a reaction chamber is provided for an ignitable gas mixture in order to inject a molding fluid, in particular the product, via the valve head into the plastic container by igniting the gas mixture.

Claims

1. Mold filling machine for molding a plastic container from a preform in a hollow mold and for filling said plastic container in said hollow mold with product and with a valve head comprising a filling member for filling a product into said plastic container in said hollow mold, wherein, a reaction chamber is provided for an ignitable gas mixture in order to inject a molding fluid, in particular said product, via said valve head into said plastic container by igniting said gas mixture.

2. The mold filling machine according to claim 1, where said mold filling machine further comprises an injection cylinder with a variable dosing chamber for dispensing said mold fluid to said valve head, and where said dosing chamber is directly or indirectly connected to said reaction chamber for pressure transfer of a said ignited gas mixture to said mold fluid.

3. The mold filling machine according to claim 2, where a movable piston or a membrane is provided in said injection cylinder for forwarding the pressure from said reaction chamber to said dosing chamber.

4. The mold filling machine according to claim 2, where said reaction chamber is formed separately from said injection cylinder and is preferably connected via lines to said injection cylinder such that the pressure in said reaction chamber is transferred to said injection cylinder via said lines.

5. The mold filling machine according to claim 2, where said reaction chamber is connected to said injection cylinder via an intermediate cylinder.

6. The mold filling machine according to claim 2, where said reaction chamber is connected to said dosing chamber via a preferably adjustable throttle.

7. The mold filling machine according to claim 2, where said reaction chamber is connected to said dosing chamber via a preferably adjustable throttle check valve which in particular comprises a ventilation connection for expelling the gas mixture consumed.

8. The mold filling machine according to claim 2, where said reaction chamber in said injection cylinder directly adjoins said dosing chamber so that a pressure of a ignited gas mixture during operation acts directly upon a surface of said molding fluid.

9. The mold filling machine according to claim 3, where said reaction chamber is formed within said injection cylinder and said movable piston or said membrane is formed as a separating element between said dosing chamber and said reaction chamber.

10. The mold filling machine according to claim 1, where said reaction chamber is connected to a gas reservoir via a valve for recycling a pressurized consumed gas mixture.

11. Mold filling method for plastic containers, where a preform is formed in a hollow mold into a plastic container by filling it with a molding fluid, in particular product, an ignitable gas mixture is ignited in a reaction chamber and said molding fluid is thereby injected via a valve head into said plastic container.

12. The mold filling method according to claim 11, where the pressure of the ignited gas mixture is transferred directly or indirectly to a variable dosing chamber of an injection cylinder.

13. The mold filling method according to claim 12, where the pressure is transferred to a movable piston or a membrane of said injection cylinder which forwards the pressure to said molding fluid in said dosing chamber.

14. The mold filling method according to claim 12, where the ignitable gas mixture is ignited within said injection cylinder as a reaction chamber so that the pressure of the ignited gas mixture acts directly upon the surface of said molding fluid.

15. The mold filling method according to claim 13, where the ignitable gas mixture within said injection cylinder as a reaction chamber is ignited and the pressure is forwarded via said movable piston or said membrane, respectively, to said molding fluid in said dosing chamber.

Description

[0035] Further features and advantages of the invention shall be explained in more detail below with reference to the embodiments illustrated in the figures, where

[0036] FIG. 1 shows an embodiment of a mold filling machine in an overview from above;

[0037] FIG. 2 shows an embodiment of a treatment station of the mold filling machine shown in FIG. 1 in a lateral view;

[0038] FIG. 3 shows an embodiment of the treatment station as an alternative to FIG. 2 in a lateral view; and

[0039] FIG. 4 shows a further embodiment of the treatment station as an alternative to FIG. 2 or 3 in a lateral view.

[0040] FIG. 1 illustrates an embodiment of a mold filling machine 1 with an upstream furnace 7 in a top view. Preforms 3 can be seen which first pass through furnace 7 and are there heated to such an extent that they can be formed into the desired container shape with downstream mold filling machine 1. The heated preforms are subsequently transferred with infeed starwheel 8 to treatment stations 5, which shall be described in more detail below with reference to FIGS. 2 [sic]. When carousel 4 rotates in direction 4a, preforms 3 are stretched in treatment stations 5, formed into the desired container shape, and filled with the molding fluid or the product, respectively. Preforms 3 or molded containers 2, respectively, always remain in hollow molds 6. After filling, containers 2 are supplied to further treatment steps via discharge starwheel 9. For example, a capper with which the plastic containers 2 are closed can be disposed downstream of or associated with mold filling machine 1. Plastic containers 2 are presently PET containers, but can be made of any other suitable plastic material.

[0041] FIG. 2 shows a lateral sectional view of a treatment station 5 of mold filling machine 1 shown in FIG. 1. It can be seen that preform 3 has already been introduced into hollow mold 6. In the region of the mouth, preform 3 has a collar and a thread, not presently shown in greater detail, which is later used to screw on a closure. Individual mold parts 6a-6c of hollow mold 6 can be moved apart and together via a multi-part mold carrier (presently not shown) in order to release the fully molded container after filling. It is also conceivable that preform 3 is either inserted into the opening of hollow mold 6 from above or is introduced into hollow mold 6 by opening and closing mold parts 6a-6c.

[0042] Valve head 10 can also be seen with filling member 11 for filling molding fluid 30 and with stretching rod 13 for stretching preform 3 during the forming process. Furthermore, valve head 10 can be moved in direction R by a moving unit or cam control (presently not shown) for lowering it onto hollow mold 6 and thereby close it off from the environment during forming and filling. It is conceivable that valve head 10 comprises sealing elements for preform 3 and/or for hollow mold 6.

[0043] Molding fluid 30 is presently directly the product to be filled, for example, mineral water or a liquid suitable for forming, and is provided via supply line 12 at a suitable pressure and is injected via filling member 11 into pre-stretched preform 3a. Pre-stretched preform 3a is pressed particularly quickly against the shaping inner surfaces of hollow mold 6 by the molding fluid and is thus molded into the finished plastic container. At the same time, the molding fluid absorbs the heat from preform 3 so that the container acquires its dimensional stability as quickly as possible after the forming process. After molding, molding fluid 30 remains as a product in finished plastic container 2. However, it is also conceivable that the molding fluid is only used for forming and again extracted before the actual product is filled. This is advantageous, for example, with pressure-sensitive products.

[0044] Intermediate states 3a, 3b can also be seen during the forming of preform 3 into finished plastic container 2 by molding fluid 30.

[0045] It can also be seen that filling member 11 is connected to injection cylinder 20 via line 12, 22. Molding fluid 30 is already pre-dosed in dosing chamber 21 of injection cylinder 20. Line 2, via which the liquid is supplied, for example, from a storage tank or a rotary distributor, is provided to supply molding fluid 30. Formed above surface 30a of molding fluid 30 within injection cylinder 20 is reaction chamber 40 into which an ignitable gas mixture is introduced via supply line 24. The ignitable gas mixture is, for example, hydrogen and oxygen or any other ignitable gas mixture. In other words, disposed within injection cylinder 20 is a chamber which is filled in one part 21 with product 30 and in second part with the ignitable gas mixture.

[0046] In order to apply the necessary pressure for forming preform 3 into plastic container 2, the ignitable gas mixture in reaction chamber is ignited electronically by way of ignition element 25. This causes the gas mixture to react and expand abruptly. The resulting pressure is released directly onto surface 30a of molding fluid 30a so that molding fluid 30 is injected into preform 3 via line 22, 12 and filling member 11 so that preform 3 expands across states 3a, 3b into finished plastic container 2. Forming can be supported by stretching rod 13, as described above. Hollow mold 6 is subsequently opened and the completely filled plastic container is dispensed.

[0047] For example, other ignitable gas mixtures which are introduced into reaction chamber 40 via a line 24 or various lines can also be used for the invention.

[0048] An embodiment of treatment station 5 as an alternative to FIG. 2 can be seen in FIG. 3 in a lateral view. It differs from FIG. 2 essentially in that movable piston 26 is arranged within injection cylinder 20. The movable piston forms a separating element between reaction chamber 40 and dosing chamber 21. Furthermore, piston 26 can be moved by way of a rod and moving unit 27 for dosing molding fluid 30 or the product using a control unit, presently not shown.

[0049] Piston 26 is first moved upwardly so that product 30 is suctioned into dosing chamber 21 via line 23. Furthermore, an ignitable gas mixture is introduced into reaction chamber 40 via line 24. As described above, the ignitable gas mixture is then ignited electronically by ignition element 25 and thereby expands abruptly. Consequently, a high pressure prevails in reaction chamber 40 and presses piston 26 downwardly in FIG. 3 with a corresponding force so that product 30 in dosing chamber 21 is injected via line 12 and filling member 11 into preform 3. The latter expands accordingly and nestles against the inner walls of hollow mold 6. Plastic container 2 is then completely filled with product 30 and can be removed from hollow mold 6, as described above.

[0050] Due to the fact that the piston is formed between reaction chamber 40 and dosing chamber 21, the ignitable gas mixture or its reaction products, respectively, does not come into direct contact with the molding fluid and contamination is consequently prevented.

[0051] FIG. 4 shows a further embodiment of treatment station 5 as an alternative to FIG. 2 or 3 in a lateral view. It differs from the embodiment in FIG. 2 essentially in that reaction chamber 40 is arranged separately from injection piston 20.

[0052] It can be seen that separate reaction chamber 40 is formed with housing 41 and ignition element 42. The ignitable gas mixture can be supplied via lines 43. As a result of the subsequent ignition of the gas mixture with ignition element 42, a high pressure builds up in reaction chamber 40 and is released into upper chamber 28 of injection cylinder 20 via line 29b, throttle check valve 50, and line 29a. Adjustable throttle check valve 50 serves to throttle the pressure build-up in such a way that the motion of piston 26 is performed in a selective or more slowly manner. Due to the pressure in chamber 28 being regulated in this manner, piston 26 is pressed onto molding fluid 30 in dosing chamber 21 so that the molding fluid is injected via line 12 and filling member 11 into preform 3 or plastic container 2. As a result, plastic container 2 is molded in hollow mold 6 and filled. Filled plastic container 2 is then ejected from hollow mold 6.

[0053] For next plastic container 2 to be filled, piston 26 is then moved upwardly again with moving unit 27 in FIG. 4 so that the consumed gas mixture in chamber 28 is injected back via line 29a into throttle check valve 50. The check valve installed there opens and the consumed gas is passed to ventilation connection 51 and can possibly be recycled. It is also conceivable that it is stored in a compressed air reservoir for pressurizing the ignitable gas mixture in reaction chamber 40 before ignition.

[0054] Furthermore, it is conceivable that reaction chamber 40 is connected to injection cylinder 20 via an intermediate cylinder. As a result, the ignited gas mixture does not reach chamber 28, whereby even the slightest contamination of product 30 is prevented for a particularly hygienic treatment.

[0055] In a modification of the embodiments in FIGS. 3 and 4, a membrane, preferably a rolling membrane, can also be used instead of piston 26. As a result, injection cylinder 20 is of an even simpler structure.

[0056] The Mold filling method describe above can be carried out according to one of claims 1-15 with a mold filling machine described in FIGS. 1-4.

[0057] It is understood that the features mentioned in the embodiments described above are not restricted to these specific combinations and are also possible in any other random combination.