DEVICE AND METHOD FOR ENSURING AN INTERNAL CONTAINER PRESSURE BY APPLICATION OF PRESSURE MULTIPLE TIMES TO THE HEAD SPACE

Abstract

Disclosed is a device and a method for filling and closing a thin-walled plastic container, in particular a PET bottle, wherein a plastic container is produced from a preform by a blow moulding process, and the plastic container is filled with a flowable medium and in particular a liquid, and also a replacement medium is introduced into the plastic container so that as the internal container pressure increases at least partial displacement of the previously contained medium takes place and the plastic container is at least partially closed, plastic container, a wall of the container closure or between a wall of the plastic container and a wall of the container closure at least one opening is introduced, and through this opening in the interior space of the plastic container a predetermined internal container pressure is set by feeding in and/or discharging a gaseous medium.

Claims

1: A method for filling and closing a thin-walled plastic container, in particular a PET bottle, wherein a plastic container is produced from a preform by a blow moulding process, and the plastic container is filled with a flowable medium and in particular a liquid, and also a replacement medium is introduced into the plastic container so that as the internal container pressure increases at least partial displacement of the previously contained medium takes place and the plastic container is at least partially closed, wherein in at least one portion of a wall of the plastic container surrounding a head space of the plastic container or a wall of the container closure at least one opening is introduced, and through this opening in the interior space of the plastic container a predetermined internal container pressure is set by feeding in and/or discharging a gaseous medium.

2: The method according to claim 1, wherein the replacement medium is nitrogen, preferably liquid nitrogen.

3: The method according to claim 2, wherein the production of the raised internal container pressure takes place by an increase in volume of the nitrogen during the transition from the liquid phase into the gaseous phase.

4: The method according to claim 2, wherein the flowable medium has a temperature above an ambient temperature, preferably in the range from 40-110 C., more preferably in the range from 50-100 C., particularly preferably in the range from 60-90 C.

5: The method according to claim 4, wherein during and/or after a process, preferably an active cooling of the filling material, the setting of the predetermined internal container pressure takes place by feeding in and/or discharging the gaseous medium.

6: The method according to claim 4, wherein an internal container pressure is set which is in the range from 1.05-7 bars, preferably 1.1-5 bars, more preferably 1.2-3 bars, particularly preferably 1.25-2 bars above the ambient pressure.

7: The method according to claim 1, wherein the opening is closed after the setting of an internal container pressure by feeding in and/or discharge of a gaseous medium.

8: A device for filling and closing a thin-walled plastic container, in particular a PET bottle, comprising a blow moulding device for producing a plastic container from a preform, a filling device for filling the plastic container with a flowable !medium, and in particular with a liquid; a closer for at least partially closing the plastic container with a container closure and at least one transport device for transporting the plastic container in a transport direction on a transport path from one of the above-mentioned processing devices to a subsequent processing device downstream, wherein on the transport path in the transport direction downstream and/or upstream of the filling device a replacement medium introduction device is arranged, by which a replacement medium can be introduced into the plastic container, wherein as a raised internal container pressure is produced the previously contained medium can be at least partially displaced, and on the transport path in the transport direction downwards of the closer a device is arranged by which an opening can be introduced in at least one portion of a wall of the plastic container surrounding a head space of the plastic container or a wall of the container closure, and wherein through this opening a predetermined internal container pressure can be set by feeding in and/or discharging a gaseous medium.

9: The device according to claim 8, wherein the replacement medium introduction device is fluidically connected to a nitrogen reservoir from which nitrogen, preferably liquid nitrogen, can be dispensed and can be metered into the plastic container.

10: The device according to claim 8, wherein the internal container pressure setting device has at least one valve which can be fluidically connected via the opening to the head space of the filled plastic container at least temporarily, is preferably regulable, and by which an internal pressure of the plastic container can be preselected.

11: The device according to claim 8, wherein on the transport path in the transport direction downstream and/or upstream of the replacement medium introduction device and upstream of the internal container pressure setting device a temperature control device, preferably a cooling device, is arranged, by means-of which the plastic container, preferably including the contained flowable medium, can be brought to a target temperature in the range from 4-70 C., preferably 10-50 C.

12: The device according to claim 8, wherein the device has a closing device configured for closing the produced opening, in particular after setting of the internal container pressure has taken place by feeding in or discharging a gaseous medium.

13: The device according to claim 9, wherein the internal container pressure setting device has at least one valve which can be fluidically connected via the opening to the head space of the filled plastic container at least temporarily, is preferably regulable, and by which an internal pressure of the plastic container can be preselected.

14: The device according to claim 9, wherein on the transport path in the transport direction downstream and/or upstream of the replacement medium introduction device and upstream of the internal container pressure setting device a temperature control device, preferably a cooling device, is arranged, by which the plastic container, preferably including the contained flowable medium, can be brought to a target temperature in the range from 4-70 C., preferably 10-50 C.

15: The device according to claim 9, wherein the device has a closing device configured for closing the produced opening, in particular after setting of the internal container pressure has taken place by feeding in or discharging a gaseous medium.

16: The device according to claim 10, wherein on the transport path in the transport direction downstream and/or upstream of the replacement medium introduction device and upstream of the internal container pressure setting device a temperature control device, preferably a cooling device, is arranged, by which the plastic container, preferably including the contained flowable medium, can be brought to a target temperature in the range from 4-70 C., preferably 10-50 C.

17: The device according to claim 10, wherein the device has a closing device configured for closing the produced opening, in particular after setting of the internal container pressure has taken place by feeding in or discharging a gaseous medium.

18: The device according to claim 11, wherein the device has a closing device configured for closing the produced opening, in particular after setting of the internal container pressure has taken place by feeding in or discharging a gaseous medium.

Description

[0088] In the drawings:

[0089] FIG. 1 shows a schematic representation of the methods for ensuring an internal container pressure through application of pressure multiple times to the head space;

[0090] FIG. 2 shows a schematic representation of a device for ensuring an internal container pressure through application of pressure multiple times to the head space;

[0091] FIG. 1 shows a schematic representation of the method for ensuring an internal container pressure through application of pressure multiple times to the head space. For this purpose, it is provided that in a first method step 1 a plastic container is produced from a preform by a blow moulding process. This is then filled with a free-flowing medium, and, in particular with a liquid, in a second method step 2. Next it is provided that in a further method step 3 the medium contained in the head space of the filled plastic container is replaced by introduction of a replacement medium as a raised internal container pressure is produced. This could take place for example by the introduction of liquid nitrogen, which evaporates upon contact with the filing material and thus as gas displaces the medium previously contained in the head space of the filled plastic container medium from this head space. At the same time the use of liquid nitrogen has the advantage that the transition into the gaseous phase takes place on the contact surface with the filling material and thus a flow of nitrogen is formed which extends from there towards the mouth and which, likewise in this direction, displaces the medium previously contained in the head space.

[0092] Alternatively, however, it would also be conceivable that in a method step 2 a replacement medium is introduced into the plastic container and in a method step 3 the plastic container is filled with a flowable medium, and in particular with a liquid, so that the replacement medium contained in the plastic container is displaced as a raised internal container pressure is produced.

[0093] After the introduction of the replacement medium and of the flowable medium, in a subsequent step 4 the plastic container is at least partially closed.

[0094] In a subsequent step 5 it is provided in a variant of the method that in at least one portion of a wall of the plastic container surrounding the head space of the container, or a wall of the container closure or a wall of the plastic container at least one opening is introduced. This step 5 is not absolutely necessary, if it is ensured by different measures that an opening is present, through which in the subsequent step 6 the feeding in and/or discharge of a gaseous medium for setting of the predetermined internal container pressure is possible. This could for example take place by only partial closing of the container in step 4, so that between the container and the closure a channel remains, through which a gas replacement is possible.

[0095] In step 6 it is provided that, by the opening introduced in step 5 or the intermediate space existing between a mouth and the container closure (which in the context of this invention should likewise be understood as an opening) in the interior of the container, a predetermined internal container pressure is set by feeding and/or discharging a gaseous medium. This could be achieved for example in such a way that at least a portion of the container, which encloses the opening, is arranged in a chamber arranged in which the required internal container pressure prevails. Thus, the required internal container pressure can also be set in the interior of the container by the gas exchange via the opening. Alternatively, the active feeding in or discharge of the gaseous medium could also be provided, for example via a hollow needle used for producing the opening in step 5.

[0096] As a further alternative it would also be conceivable that, after the method steps 1-3, in a fourth method step 4 for setting a predetermined internal container pressure a gaseous medium is introduced into the plastic container, and in a fifth method step 5 the container is closed at least temporarily during the introduction of the gaseous medium. In this procedure there is no need for the method step 6. Potentially, however, a repeated, preferably partial opening of the closure could be provided, in orderfor example after setting a target temperature of the filling materialto be able to set a required internal container pressure preferably permanently.

[0097] FIG. 2 shows a schematic representation of a device 10 for ensuring an internal container pressure through application of pressure multiple times to the head space. In this case FIG. 2 shows by way of example the variant of the method in which the plastic container is initially filled, then a replacement medium is introduced into the plastic container and the container is then closed.

[0098] The device 10 comprises a blow moulding device (not shown), which produces plastic containers 11 from preforms. These are fed to a filling device 14, where they are filled with a flowable medium, and in particular with a liquid. The filling material may be, in particular a beverage. This is preferably a filling material which is introduced while hot. The hot filling is advantageous in particular in the case of perishable or sterile filling materials, since in this way the contamination with heat-sensitive germs can be at least largely avoided and at least a certain sterility can be ensured. Therefore, it is possible and in many cases even advantageous if at least several of the processing devices 14, 18, 19, 22 of the device are arranged inside a clean room (not shown).

[0099] The filling device 14 is preferably a rotating filling device, which has along the circumference of a carrier wheel 13 a plurality of processing devices 12, in this case filling elements, through which the filling material can be introduced in each case into one of the containers 11.

[0100] Then the filled containers 11 are preferably transferred by means of a transfer device 15 to a replacement medium introduction device 18, which dispenses a replacement medium into the head space of the filled plastic container. The transfer device 15 is preferably designed as a transfer starwheel and preferably has holding devices 16, which preferably in each case can accommodate a container 11. At the same time the transfer device 15 also constitutes a transport device for transporting plastic containers 11 in a transport direction along a transport path. The transfer device 15 can be designed so that it changes the pitch of the containers, that is to say the spacing between two successive containers along the transport path.

[0101] In the illustrated embodiment the containers 11 are also transported to the respective processing devices 14, 18, 19, 22 during the individual processing steps, so that the processing devices 14, 18, 19, 22 themselves are also transport devices.

[0102] In the replacement medium introduction device 18 shown on the transport path downstream of the transfer device 15 in the transport direction the medium contained in the head space of the filled plastic container is replaced at least by introduction of a replacement medium as a raised internal container pressure is produced. For this purpose, at least one, preferably a plurality of replacement medium introduction devices 17 is arranged on the replacement medium introduction device 18. In the illustrated example the replacement medium introduction device 18 is also designed as a closer 18, so that on the same carrier wheel the plastic container is also closed at least partially by a container closure. The closing takes place in a sector of the circular segment-shaped transport path formed by the carrier wheel, which follows the sector in which the replacement medium is introduced into the filled plastic container.

[0103] In the present case the introduction of liquid nitrogen is provided. This evaporates upon contact with the filling material and because its volume increases multiple times in this case it drives the medium previously contained in the head space out of the container 11. Since the transition into the gaseous phase occurs primarily at the contact surface with the filling material, on the underside of the liquid nitrogen a gas cushion forms which acts as an isolation layer and delays the evaporation of the nitrogen. In this way it is ensured that for some time liquid nitrogen is available in the interior of the container. So long as there is still liquid nitrogen in the interior of the container, due to the progressive evaporation thereof a continuous gas stream is produced in the direction of the mouth, by which the medium previously contained in the head space is expelled and contamination of the filling material and of the interior of the container from the exterior is avoided. The closure is preferably applied to the container by the closer 18 during this phase.

[0104] The nitrogen which evaporates after this can no longer flow out unhindered through the mouth, so that a positive pressure is established in the interior of the container. In the event of only partial closing of the container the pressure can be reduced slowly through the remaining opening, but over a relatively long time period it remains above the ambient pressure, so that furthermore contamination due to the inflow of foreign substances from the exterior can be avoided.

[0105] The positive pressure remaining in the container 11 is necessary in order to avoid the penetration of germs during the subsequent temperature control in the temperature control device 19. Since during the cooling of the filling material the volume thereof usually decreases, it is possible to (over-)compensate for this decrease in volume by the positive pressure existing in the head space, so that overall the internal container pressure remains above the ambient pressure.

[0106] The temperature control device 19 preferably has at least one dispensing device 20 for a temperature control medium. A plurality of these dispensing devices 20 are preferably provided, which are arranged in the temperature control device 19 along the transport path and during the transport of the containers through the temperature control device 19 applies the temperature control medium to the containers. In a preferred embodiment the temperature control device 19 is a cooling device, which particularly preferably applies cooling water to the containers to be cooled. If heating of the containers is required (for example in order to bring them to a target temperature again after cooling) for example radiation such as IR and/or microwave radiation could be used as temperature control medium.

[0107] An internal container pressure setting device 22 is arranged on the transport path in the transport direction downstream of the closer 18 and in the present example also downstream of the temperature control device 19. After the at least partial closing and the temperature control the containers are fed by means of a transfer device 21 to the internal container pressure setting device 22. In this internal container pressure setting device 22 processing devices 23 are provided, which can grip and transport the container and furthermore during the transport through an opening can set a predetermined internal container pressure by feeding in and/or discharging a gaseous medium. For this purpose, a reservoir (not shown) of the gaseous medium can be provided, from which gas which is lacking or excessed gas is discharged into or fed from the head space of the container. For this purpose, the head space of the container and the reservoir are at least temporarily in fluid connection.

[0108] The at least one opening is arranged in a portion of a wall of the plastic container 11 surrounding the head space of the container or a wall of the container closure or is formed by an intermediate space existing between a mouth of the plastic container 11 and the container closure. The opening can be introduced for example by means of a penetration device (not shown). This could be part of the processing device 23 and thus of the internal container pressure setting device 22.

[0109] The applicant reserves the right to claim all the features disclosed in the application documents as essential to the invention in so far as they are individually or in combination novel over the prior art.

LIST OF REFERENCES

[0110] 1-6 method step [0111] 10 device [0112] 11 container [0113] 12 processing device [0114] 13 carrier wheel [0115] 14 filling device [0116] 15 transfer device [0117] 16 holding device [0118] 17 replacement medium introduction unit [0119] 18 replacement medium introduction device, closer [0120] 19 temperature control device [0121] 20 dispensing device [0122] 21 transfer device [0123] 22 internal container pressure setting device [0124] 23 processing device