METHOD AND APPARATUS FOR PRODUCING LIQUID-CONTENTS-FILLED CONTAINERS FROM PREFORMS BY CONTENTS BEING INTRODUCED INTO THE PREFORM UNDER PRESSURE

Abstract

The present invention relates to a method and an apparatus for producing containers filled with a liquid filling material from preforms by introducing pressurized filling material into the preform. The object of the invention is to propose such a method and such an apparatus in which both the desired filling pressure and the desired volumetric flow rate of the filling material are reliably available throughout the entire molding and filling phase. The object of the invention is achieved by a method in which the filling material is pressurized by a pressure pump 7 and is introduced into the preform 1 through a filling valve 6 at a molding and filling station 3, said method being characterized in that, when the filling valve 6 is closed, a pressure accumulator 10 disposed between the pump 7 and the filling valve 6 is pressurized by the pump 7 and filled with a volume of filling material, and when the filling valve 6 is open, the pressure accumulator 10 delivers the accumulated pressurized filling material to the preform 1. The object of the invention is further achieved by a corresponding apparatus that comprises a pressure pump 7 and a filling valve 6, connected to one another by a feed line 2, characterized in that said apparatus comprises a pressure accumulator 10, disposed in the feed line 2 between the pressure pump 7 and the filling valve 6.

Claims

1. A method for simultaneously producing a container from a preform and filling the container with a liquid filling material, the method comprising: introducing the liquid filling material into the preform under pressure; wherein the liquid filling material is pressurized by a pressure pump and is introduced into the preform through a filling valve at a molding and filling station, wherein, when the filling valve is closed, a pressure accumulator disposed between the pump and the filling valve is pressurized by the pump and is filled with a volume of liquid filling material, and wherein, when the filling valve is open, the pressure accumulator delivers the liquid filling material pressurized in the pressure accumulator to the preform.

2. The method according to claim 1, wherein the pump is a continuously running pump.

3. The method according to claim 1, wherein the pump has a working pressure that is equal to at least a maximum filling pressure.

4. The method according to claim 1, wherein the pressure accumulator has a preload pressure that is equal to a minimum molding and filling pressure.

5. The method according to claim 3, wherein, at the working pressure of the pump, a volume of filling material admitted to the pressure accumulator is equal to at least a volume of a container to be molded from the preform.

6. An apparatus for simultaneously producing a container from a preform and filling the container with a liquid filling material by introducing the liquid filling material under pressure into the preform while the preform is disposed within a mold at a molding and filling station, said apparatus comprising: a pressure pump and a filling valve, which are connected to one another by a feed line; and a pressure accumulator disposed in the feed line between the pressure pump and the filling valve.

7. The apparatus according to claim 6, wherein the pump is a continuously running pump.

8. The apparatus according to claim 6, wherein the pump has a working pressure that is equal to at least a maximum filling pressure.

9. The apparatus according to claim 6, wherein the pressure accumulator has a preload pressure that is equal to a minimum molding and filling pressure.

10. The apparatus according to claim 6, wherein the pressure accumulator is a pressurized gas accumulator.

11. The apparatus according to claim 8, wherein, at the working pressure of the pump, a volume accommodated by the pressure accumulator is equal to at least a volume of the mold.

12. The apparatus according to claim 6, wherein a flow check valve is disposed between the pressure pump and the pressure accumulator.

13. The apparatus according to claims 6, wherein a damping element is disposed in the feed line (2).

14. The apparatus according to claim 13, wherein the damping element has a maximum liquid capacity of 500 ml.

15. The apparatus according to claim 13, wherein the damping element is disposed near the molding and filling station.

16. The apparatus according to claim 13, wherein the damping element is a pressurized gas accumulator.

17. The apparatus according to claim 13, wherein the damping element is a piston biased in a cylinder by a spring force or by gas pressure.

18. The apparatus according to claim 13, wherein the damping element has a maximum liquid capacity of 300 ml.

19. The apparatus according to claim 13, wherein the damping element has a maximum liquid capacity of 150 ml.

20. The apparatus according to claim 15, wherein the damping element is disposed near a molding and filling head of the molding and filling station.

Description

[0038] In the following, an exemplary embodiment of the invention will be described in greater detail with reference to the accompanying FIGURE.

[0039] FIG. 1 is a diagram illustrating the configuration of an exemplary embodiment of an apparatus according to the invention.

[0040] It will be obvious to a person skilled in the art that the exemplary embodiment illustrated here is intended merely to illustrate the principle of the invention, and that it is rendered only schematically and not to scale. In particular, the relative dimensions and proportions of the elements in the diagram are intended merely as illustrative. The actual dimensions and proportions may be determined by a person skilled in the art based on his knowledge in the art. Furthermore, only those components that are necessary for an understanding of the invention are shown. Actual apparatus may include additional components.

[0041] The apparatus shown includes a molding and filling station 3, in which a preform 1 is shaped into a filled container inside a mold 4. For this purpose, the molding and filling station 3 is equipped with a molding and filling head 5 having a filling valve 6, which is connected to a feed line 2 through which filling material can be supplied under pressure from a reservoir 9 to the molding and filling station 3.

[0042] To mold and fill a container, the molding and filling head 5 is placed on the mouth of preform 1, forming a tight seal, and filling material is fed at a pressure of 36 to 40 bar to preform 1 within a maximum filling time of 150 ms. For a 1.5 liter bottle, this requires a volumetric flow rate of the filling material of at least 10 liters per second.

[0043] For this purpose, the apparatus is equipped with a pump 7, which runs continuously and achieves a pressure of 40 bar. Downstream of the pump, feed line 2 is equipped with a flow check valve 8.

[0044] The apparatus additionally includes a pressure accumulator 10, preloaded with a gas. The pressure accumulator is preloaded at 36 bar, for example, and can accommodate a volume of 1.5 liters at a pressure of 40 bar, for example. The running pump 7 pressurizes the filling material in feed line 2 to 40 bar, so that the gas in pressure accumulator 10 is compressed and the pressure accumulator admits 1.5 liters of the filling material. When a pressure of 40 bar is reached, the pressure accumulator stops admitting filling material. The filling material being conveyed by pump 7 is returned to reservoir 9 via pressure relief valve 11 and return line 12.

[0045] Once pressure accumulator 10 is completely filled, filling valve 6 can be opened. The filling material stored in pressure accumulator 10 flows through molding and filling head 5 and into preform 1 at the initial pressure of 40 bar and at a high volumetric flow rate, with the action of the filling material shaping the preform into the container while simultaneously filling it inside mold 4. The pressure in accumulator 10 then drops to 36 bar, which is sufficient for molding the container, until the molding and filling of the container are completed.

[0046] Pressure accumulator 10 responds quickly and without delay and, unlike the pump 7, is capable of supplying the volumetric flow required for the short filling time. The container can thus be molded from the thermally conditioned preform 1 before the temperature of the preform 1 drops below the level at which the preform is moldable.

[0047] Once molding and filling valve 6 has been closed, the molded container can be separated from molding and filling head 5 and further processed, in particular by sealing, labeling, etc. Pump 7 continues to run, refilling pressure accumulator 10 for the next molding and filling operation.

[0048] The apparatus according to the invention has the advantage that a simple pump 7 with a conventional output capacity can be used, since the high volumetric flow rate required briefly for the molding and filling operation can be stored by pressure accumulator 10 and supplied as needed.

[0049] In an industrial system, the output capacity of pump 7 must be designed to correspond to the fill quantity per unit of time. The high volumetric flow rates required during the molding and filling phase are achieved by filling and emptying pressure accumulator 10. The volume of pressure accumulator 10 should be sufficient to accommodate the container volume during the molding and filling of a container. When a plurality of containers are molded and filled in overlapping operations at different molding and filling stations 3 connected to pressure accumulator 10, the volume of pressure accumulator 10 must be increased accordingly. Of course, it is also possible for the dimensions of the accumulator in terms of volume available for filling material to be increased.

[0050] A damping element 20 may optionally be connected to feed line 2. This may be a pressurized gas accumulator, for example, in which a pressurized gas cushion 20a is trapped behind a membrane 20b. Here, the gas pressure is equal to the maximum molding and filling pressure of the apparatus, for example 38 bar. However, the molding and filling pressure used may be different depending on the container to be formed. Typically, the pressure of the gas cushion in the pressure accumulator may be between 36 and 44 bar, preferably between 40 and 42 bar.

[0051] When a preform 1 is shaped into a filled container by the introduction of filling material within approximately 100 to 150 ms, the high volumetric flow of the filling material causes a pressure surge once the container is fully formed and its wall is in contact with the wall of mold 4. A pressure peak occurs, which travels backward through the system in the form of a pressure wave. The level of the pressure peak is difficult to calculate. However, the components of the system are typically designed to withstand only the filling pressure plus a safety margin. Constant pressure surges can damage the components.

[0052] Damping element 20 can dampen the pressure wave by briefly admitting a small volume of filling material. For this purpose, damping element 20 is disposed close to molding and filling head 5, thereby restricting the propagation of the pressure wave to a limited area of the system and effectively protecting the components disposed upstream.

[0053] Although pressure propagates in all directions in the system of lines, pressure surges that occur travel at a finite speed in the form of a wave. It is therefore advantageous for damping element 20 to be disposed such that the propagation direction of the wave is roughly perpendicular to the membrane, as this enables particularly effective damping of the pressure wave.

[0054] Although pressure accumulator 10 and damping element 20 appear to be structurally similar, they possess significant differences in detail.

[0055] Specifically, pressure accumulator 10 should always be designed as greater than the volume of a container to be produced, whereas the volume of damping element 20 can be much smaller than the container volume.

[0056] Furthermore, damping element 20 is preferably disposed close to or even integrated into molding and filling head 5, whereas pressure accumulator 10 feeds a supply line leading to molding and filling head 5, and even longer pipe routes between pressure accumulator 10 and molding and filling head 20 are non-problematic.

[0057] Finally, machines having a plurality of molding and filling stations 3 will preferably each have one damping element 20 per molding and filling station 3 or per molding and filling head 5, whereas multiple or all molding and filling stations 3 are preferably fed by the same pressure accumulator 10.