Method and apparatus for producing liquid-contents-filled containers from preforms by contents being introduced into the preform under pressure

Abstract

The invention relates to a method and an apparatus for producing liquid-contents-filled containers (22) from preforms (1) by contents being introduced into the preform (1) under a filling pressure, wherein the contents are placed under pressure by a pressure pump (7) and are introduced into the preform (1) at a molding and filling station (3) by a filling valve (6). A pressure accumulator (10) arranged between the pressure pump (7) and the filling valve (6) is subjected to pressure and is filled with a volume of contents by the pressure pump (7). The invention is distinguished in that a displacement pump (26) having a filling chamber (28) for the contents and having a displacement body (30) guided so it is movable therein is provided, wherein the displacement body (30) divides the chamber (28) into a first partial chamber (28a) on the filling station side and a second partial chamber (28b) facing away from the filling station, each of which can be brought into a fluidic connection with the pressure accumulator (10). The displacement body (30) has a drive connection to a drive unit (32) and is drivable by the drive unit (32), wherein when the filling valve (6) is opened, the drive unit (32) and/or the pressure accumulator (10) each at least temporarily apply a drive force to the displacement body (30), and at the same time the displacement body (30) displaces at least a part of the quantity of contents required for the forming of the preform (1) in the direction of the preform (1).

Claims

1. A method for producing a liquid-contents-filled container from a preform, the method comprising: introducing liquid contents into the preform under a filling pressure; wherein the liquid contents are placed under pressure by a pressure pump and are introduced into the preform at a molding and filling station by a filling valve, wherein a pressure accumulator arranged between the pressure pump and the filling valve is subjected to pressure and is filled with a volume of the liquid contents by the pressure pump, wherein a displacement pump is provided, said displacement pump having a filling chamber for the liquid contents and a displacement body movably guided in the filling chamber, wherein the displacement body divides the filling chamber into a first partial chamber and a second partial chamber, wherein a first connecting line leads from the pressure accumulator to the first partial chamber and a second connecting line leads from the pressure accumulator to the second partial chamber, wherein the first partial chamber is fluidly connected to the filling valve via a communication path that does not include the pressure accumulator, wherein the displacement body includes a drive connection to a drive unit, and wherein, when the filling valve is opened, one or both of the drive unit and the pressure accumulator at least temporarily apply a drive force to the displacement body, and, at the same time, the displacement body displaces at least a part of a quantity of the liquid contents required to produce the liquid-contents-filled container in a direction toward the preform.

2. The method as claimed in claim 1, wherein the displacement body displaces all of the quantity of the liquid contents required to produce the liquid-contents filled container in the direction toward the preform.

3. The method as claimed in claim 1, wherein the molding and filling station is one of multiple molding and filling stations arranged on a shared continuously rotating operating wheel.

4. The method as claimed in claim 1, wherein, simultaneously during the introduction of the liquid contents into the preform, a stretching rod at least partially stretches the preform in an axial direction of the preform.

5. The method as claimed in claim 1, wherein the displacement pump is a reciprocating piston pump.

6. The method as claimed in claim 1, wherein a pressure equalization takes place between the first partial chamber and the second partial chamber before the filling valve is opened.

7. The method as claimed in claim 1, wherein the drive unit is a path controlled drive unit.

8. The method as claimed in claim 1, wherein either one or both of the first connecting line is valve controlled and the second connecting line is throttleable.

9. The method as claimed in claim 8, wherein the first connecting line is closed before the filling valve is opened, or the first connecting line is closed simultaneously as the filling valve is opened.

10. The method as claimed in claim 1, wherein a flow cross section of the second connecting line is larger than a flow cross section of a supply line from the first partial chamber to the preform.

11. An apparatus for producing a liquid-contents-filled container from a preform by introducing liquid contents into the preform inside a mold under pressure in a molding and filling station, the apparatus comprising: a pressure pump; a pressure accumulator; a displacement pump; and a filling valve; wherein the pressure pump and the filling valve are fluidly connected to one another, at least in part, by a supply line, wherein the pressure accumulator is arranged in the supply line between the pressure pump and the filling valve, wherein the displacement pump includes a filling chamber for the liquid contents, wherein a movably guided displacement body is provided in the filling chamber, wherein the displacement body divides the filling chamber into a first partial chamber and a second partial chamber, wherein a first connecting line leads from the pressure accumulator to the first partial chamber, wherein a second connecting line leads from the pressure accumulator to the second partial chamber, wherein the first partial chamber is fluidly connected to the filling valve via a communication path that does not include the pressure accumulator, wherein the displacement body includes a drive connection to a drive unit, wherein the apparatus is configured such that when the filling valve is opened, the displacement body is subjected at least temporarily by one or both of the drive unit and the pressure accumulator to a drive force that moves the displacement body within the filling chamber such that the displacement body displaces at least a part of a quantity of liquid contents required produce the liquid-contents-filled container in a direction toward the preform.

12. The apparatus as claimed in claim 11, wherein the displacement body displaces all of the quantity of liquid contents required to produce the liquid-contents-filled container in the direction toward the preform.

13. The apparatus as claimed in claim 11, wherein the molding and filling station is one of multiple molding and filling stations arranged on a shared, continuously rotating operating wheel, and wherein one or both of the displacement pump and the pressure pump is also arranged on the operating wheel.

14. The apparatus as claimed in claim 11, wherein the molding and filling station has a stretching rod, which, simultaneously during the introduction of the liquid contents into the preform, at least temporarily stretches the preform in an axial direction of the preform.

15. The apparatus as claimed in claim 11, wherein the displacement pump is a reciprocating piston pump.

16. The apparatus as claimed in claim 11, wherein the first partial chamber and the second partial chamber are connectable to one another for pressure equalization before the filling valve is opened.

17. The apparatus as claimed in claim 11, wherein the drive unit is a path controlled drive unit.

18. The apparatus as claimed in claim 11, wherein one or both of the first connecting line is valve controlled and the second connecting line is throttleable.

19. The apparatus as claimed in claim 18, wherein a flow cross section of the second connecting line is larger than a flow cross section of the supply line to the preform.

Description

(1) Exemplary embodiments of the invention are schematically illustrated in the following drawings. In the figures:

(2) FIG. 1 shows the schematic construction of a molding and filling apparatus using a pressure accumulator according to the prior art,

(3) FIG. 2 shows a schematic illustration of the fundamental construction of an exemplary embodiment of an apparatus according to the invention and a method according to the invention.

(4) It is obvious to a person skilled in the art that the exemplary embodiments illustrated here are merely to be used to illustrate the principle of the invention and the illustrations are only schematic and are not to scale. In particular, the dimensions and size ratios of the elements shown in relation to one another are only to be used for illustration. The actual dimensions and size ratios can be determined freely by a person skilled in the art on the basis of his knowledge in the art. In addition, only the components required for understanding the invention are shown. Real apparatuses can have further components.

(5) The illustrated apparatus has a molding and filling station 3, in which a preform 1 is formed inside a mold 4 into a filled container 22. For this purpose, the molding and filling station 3 has a molding and filling head 5 having a filling valve 6, which is connected to a supply line 2, by which contents can be supplied under pressure to the molding and filling station 3 from a reservoir 9.

(6) For molding and filling a container 22, the molding and filling head 5 is placed on the orifice of the preform 1 to form a seal and contents are supplied to the preform 1 at a pressure of, for example, 36 to 40 bar within the filling time of, for example, at most 150 ms. In the case of a 1.5 L bottle, for example, this requires a volume flow of the contents of at least 10 L/second.

(7) For this purpose, the apparatus is equipped with a pump 7, which runs continuously and reaches a pressure of 40 bar. The supply line 2 is provided with a check valve 8 behind the pump 7.

(8) Furthermore, the apparatus has a pressure accumulator 10 pre-tensioned using a gas. The pressure accumulator 10 is pre-tensioned at 36 bar, for example, and can absorb a volume of, for example, 1.5 L at a pressure of, for example, 40 bar. This volume would be selected as larger, for example, for filling larger containers 22. The running pump 7 places the contents in the supply line 2 under a pressure of 40 bar, and therefore the gas in the pressure accumulator 10 is compressed and the pressure accumulator absorbs 1.5 L of the contents. Upon reaching the pressure of 40 bar, the pressure accumulator 10 does not absorb any further contents. The contents conveyed by the pump 7 are guided via the overpressure valve 11 and the return line 12 back into the reservoir 9.

(9) If the pressure accumulator 10 is completely filled, the filling valve 6 can be opened. The contents stored in the pressure accumulator 10 flow under the initial pressure of 40 bar and with high volume flow through the molding and filling head 5 into the preform 1, which is formed under the action of the contents inside the mold 4 into the container 22 and is filled simultaneously. The pressure in the pressure accumulator 10 drops to 36 bar, which is sufficient for the container forming, up to the complete molding and filling of the container 22.

(10) The pressure accumulator 10 reacts rapidly and without delay and, in contrast to the pump 7, can provide the volume flow required for the short filling time. The container 22 can thus be formed from the thermally conditioned preform 1 before the temperature of the preform 1 drops enough that it is no longer moldable.

(11) After the closing of the molding and filling valve 6, the molded container 22 can be separated from the molding and filling head 5 and further processed, in particular by closing, labeling, etc. The pump 7 runs further continuously and fills the pressure accumulator 10 again for the next molding and filling procedure.

(12) The apparatus according to the invention has the advantage that a simple pump 7 having a typical liter output can be used, since the high volume flow briefly required for the molding and filling procedure can be stored by the pressure accumulator 10 and dispensed as needed.

(13) In an industrial facility, the liter output of the pump 7 has to be designed such that it meets the filling quantity per unit of time. The high required volume flows during the molding and filling phase are achieved, inter alia, by filling and emptying the pressure accumulator 10. The pressure accumulator 10 is to be designed with respect to the volume in this case such that in the case of the molding and filling of the container 22, it can absorb the container volume at the time. In the case of chronologically overlapping molding and filling of multiple containers 22 in different molding and filling stations 3 connected to the pressure accumulator 10, the volume of the pressure accumulator 10 is to be elevated accordingly.

(14) A damping element 20 is optionally connected to the supply line 2. This is a gas pressure accumulator, for example, in which a gas cushion 20a under pressure is enclosed behind a membrane 20b. The gas pressure corresponds in this case to the maximum molding and filling pressure of the apparatus, for example, 38 bar. Depending on the container 22 to be molded, however, the molding and filling pressure used can be different. The pressure of the gas cushion 20a in the pressure accumulator 10 can typically be between 36 and 44 bar, preferably between 40 and 42 bar.

(15) When the preform 1 is formed into a filled container 22 by the introduction of the contents within approximately 100 to 150 ms, a pressure surge occurs at the same time as a result of the high volume flow of the contents, when the container 22 is completely formed and its wall bears on the wall of the form 4. A pressure peak occurs, which propagates in reverse in the facility as a pressure wave. The level of the pressure peak can only be computed with difficulty. The components of the facility are generally only designed for the filling pressure plus a safety margin, however. Continuous pressure surges can damage the components.

(16) The damping element 20 can damp the pressure wave by way of the brief absorption of a small volume of contents. The damping element 20 is arranged for this purpose close to the molding and filling head 5, and therefore the propagation of the pressure wave is limited to a restricted region of the facility and the upstream components are effectively protected.

(17) Pressure does propagate on all sides in the line system but occurring pressure surges propagate at finite speed as a wave. It is therefore advantageous for the damping element 20 to be arranged such that the propagation direction of the wave is approximately perpendicular to the membrane, since the pressure wave is then damped particularly effectively.

(18) Although pressure accumulator 10 and damping element 20 appear structurally similar, substantial differences nonetheless result in detail.

(19) The pressure accumulator 10 is thus always to be selected in particular as larger than the volume of a container 22 to be produced, while the volume of the damping element 20 can be selected as very much smaller than the container volume.

(20) Furthermore, the damping element 20 is preferably arranged close to or is even integrated into the molding and filling head 5, while the pressure accumulator 10 feeds a supply line to the molding and filling head 5 and longer pipe sections between pressure accumulator 10 and molding and filling head 20 are also not problematic.

(21) Finally, machines having multiple molding and filling stations 3 will have one damping element 20 per molding and filling station 3 or per molding and filling head 5, respectively, while multiple or all molding and filling stations 3 can be fed by the same pressure accumulator 10.

(22) FIG. 2 shows an exemplary embodiment according to the invention, which is supplemented with a displacement pump 26 in relation to the exemplary embodiment shown in FIG. 1 but can otherwise have the construction explained with reference to FIG. 1. In addition to the pressure accumulator 10 and the reservoir 9 already described with respect to FIG. 1 and also the pressure pump 7, a second pump unit is shown, which is embodied in the exemplary embodiment shown as a displacement pump 26, namely as a piston pump. A movable piston 30 is guided as a displacement body in a filling chamber 28 of the displacement pump 26.

(23) A drive motor 32 engages as a drive unit on a piston rod 29 protruding axially out of the filling chamber 28. The piston 30 divides the filling chamber 28 into a lower partial chamber 28a and an upper partial chamber 28b. The upper partial chamber 28b is connected via a connecting line 38 having a flow cross section A to the pressure accumulator 10. A throttle 40, as is indicated by means of dashed lines, can be arranged in this connecting line 38.

(24) A valve V1, which controls the connection 36 between the pressure accumulator 10 and the lower part 28a of the filling chamber 10, is arranged in the connecting line 36 to the lower part 28a of the filling chamber 28. In the exemplary embodiment shown, this valve V1 corresponds to the inlet valve of a typical displacement pump, while the valve V2 in the supply line 2 to the molding and filling station 3 corresponds to the outlet valve of a typical displacement pump. The filling valve 6 of FIG. 1 corresponds to the valve V2 in FIG. 2. Although V2 is shown spaced apart from the filling head, it is considered to be preferable if this filling valve V2 or 6 is arranged as close as possible to the outlet of the contents into the preform 1, as is known in the field of fillers, to avoid dripping, dead spaces in the content supply line, and hygienic problems.

(25) If the outlet valve V2 is closed, thus, for example, the same pressure is applied in the lower and in the upper part 28a, 28b of the filling chamber 28 when the valve V1 is open, namely the pressure which prevails in the pressure accumulator 10. In this pressure-equalized state, the piston 30 can be driven by the motor 32, without having to overcome a pressure difference.

(26) For the purpose of molding and filling, valve V2 is opened and valve V1 is closed simultaneously or earlier in time. The piston 30 moves in a conveyance direction solely because of the pressure difference on the preform side of the valve V2 in relation to the region of the valve V2 on the pressure accumulator side, because the pressure in the pressure accumulator 10 is applied via the connecting line 38 in the upper partial chamber 28b, while a pressure reduction occurs in the lower partial chamber 28a of the filling chamber 28, since the valve V2 is open. The piston 30 is thus already driven by the pressure in the pressure accumulator 10 and by the connection shown between the pressure chamber 10 and the displacement pump 26. In addition, a further drive force can be applied by the drive unit 32, which is embodied, for example, as a linear motor, and therefore in this case the drive unit 32 together with the pressure accumulator 10 forms the conveyance pressure of the contents into the preform 1.

(27) If a throttle valve 40 having controllable cross section is arranged in the connecting line 38 to the upper partial chamber 28b of the filling chamber 28, the inflow of contents from the pressure accumulator 10 can be reduced by targeted constriction of the cross section of the connecting line 38 and the piston movement can thus be slowed. The piston movement can also be changed by the drive unit 32, for example, braked. It is also possible to embody the filling valve V2 so it can be throttled. Upon throttling of the inflow of contents into the preform 1 at the end of the filling procedure, braking of the piston 30 also occurs, since it has to work against a pressure which becomes greater.

(28) The drive unit 32 can move the piston 30 with a specific movement profile, for example, i.e., with a higher speed at the beginning, for example, in order to start the molding and filling procedure with a high filling pressure and a high flow volume. After such a starting phase, the speed can then be reduced in order to be braked at the end of the molding and filling procedure to avoid a strong blowback upon reaching the complete formation state of the container 22.

(29) With ending of the molding and filling procedure, the filling valve V2 is closed and the inlet valve V1 is opened. The piston 30 can then be raised again by a motor, wherein a pressure equalization occurs again in both partial chambers 28a, 28b of the piston chamber 28 with opening of the valve V1. No pressure difference in relation to the upper partial chamber 28b is thus to be overcome for the suctioning of the contents into the lower partial chamber 28a, and the motor power to be applied for the suction movement of the piston 30 is therefore low.

(30) In FIG. 2, in contrast to FIG. 1, the molding and filling station 3 is formed having a stretching rod 24, which is movable in the direction of the arrow P, for example, driven by a motor or, for example, driven by an external control curve. At the beginning of the molding and filling process, the stretching rod 24 is moved against the closed end of the preform 1 and upon further movement in this axial direction it stretches the preform 1 in its axial direction. As soon as the preform 1 has reached the desired axial stretching, the stretching rod 24 can be guided back out of the preform 1 or out of the resulting container 22, respectively.

(31) An operating wheel of the molding and filling machine is indicated with reference numeral 34. The basic construction described on the basis of schematic FIGS. 1 and 2 can thus have multiple molding and filling stations 3, which are arranged spaced apart on the circumference on this rotating operating wheel 34. During the regular molding and filling process of the molding and filling machine, the operating wheel 34 revolves continuously and per revolution, each of the molding and filling stations 3 is equipped once with a preform 1, it molds this preform into a container 22 by introducing the contents, and the finished formed and filled container 22 is removed. There is a similarity to the known blowing wheels of a blow molding machine with respect to this functionality, see, for example, WO 2012/083910 A1.

(32) With respect to the arrangement of the pressure pump 7, the pressure accumulator 10, and the displacement pump 26, there are different options in the case of the provision of the molding and filling stations 3 on an operating wheel 34. One possible embodiment is shown in FIG. 2. The pressure pump 7 is arranged in a stationary manner outside the operating wheel 34 in this case and the pumped contents are transferred to the operating wheel 34 via a rotary connection. The reservoir 9 (not shown in FIG. 2), would also be arranged in a stationary manner outside the operating wheel 34. The pressure pump 7 can be arranged to co-rotate on the operating wheel 34, whereby the rotary connection then has to meet lesser requirements with respect to the pressure tightness. This construction variant is thus advantageous.

(33) The pressure accumulator 10 is arranged on the operating wheel 34 and corotating therewith. This pressure accumulator 10 supplies all molding and filling stations 3 on the operating wheel 34 with contents under pressure. It would also be conceivable to provide more than one pressure accumulator 10 on the operating wheel 34, by each of which only an associated part of the molding and filling stations 3 is supplied with contents. A separate pressure accumulator 10 could even be associated with each molding and filling station.

(34) The displacement pump 26 is preferably arranged on the rotating operating wheel 34 and furthermore preferably at a short distance to the associated molding and filling station 3, in order to achieve short line paths between the displacement pump 26 and the molding and filling station 3. In this case, a separate displacement pump 26 is preferably associated with each molding and filling station 3.

(35) With respect to the machine components of FIG. 1 not shown in FIG. 2, thus in particular with respect to the damping element 20, in contrast, a separate damping element 20 is preferably associated with each molding and filling station 3, which would also be arranged on the operating wheel 34 upon implementation of the molding and filling station according to the rotary filling principle.

LIST OF REFERENCE SIGNS

(36) 1 preform 2 supply line 3 molding and filling station 4 mold 5 molding and filling head 6 filling valve 7 pressure pump 8 check valve 9 reservoir 10 pressure accumulator 11 overpressure valve 12 return line 20 damping element 20a gas cushion 20b membrane 22 container 24 stretching rod 26 displacement pump 28 filling chamber 28a first partial chamber 28b second partial chamber 29 piston rod 30 displacement body 32 drive unit 34 operating wheel 36 connecting line to 28a 38 connecting line to 28b 40 throttle, controllable V1 valve V2 valve, filling valve P movement direction of stretching rod