HK1248192B - Method for gas filling of a compartment of a flexible container - Google Patents

Description

Method for gas filling of a cavity of a flexible container

Technical Field

The present invention relates to a method for processing containers of the collapsible type, and more particularly to such a method for processing containers in a filling machine comprising stations arranged in succession, including a filling station and a gas filling station.

Background Art

The use of containers of the collapsible type has long been known, for example for food or consumable materials such as hygiene products and detergents. The contents can be in liquid and powder form.

A collapsible container means that the container is made of thin flexible walls that are joined at a connection to define a product cavity. The volume of the product cavity depends on the relative distance between the walls, which means that the volume depends on the fill rate of the container.

Containers of this type are available with several different handle shapes, such as shown in WO 2005/030599 or WO 2006/121388.

The container may include a handle cavity at its rear end in the form of a handle, which is intended to be filled with gas to form a handle that can be grasped by a user to handle the container like a kettle. The handle cavity may include three sections, a first section of which is intended to form the actual handle; a second section providing an inlet through which the handle cavity communicates with the surroundings; and a third section connecting the first section to the second section.

To fill the handle cavity with gas, a nozzle of a gas filling device is applied above an inlet through which gas is supplied to the handle cavity. In response to the supplied gas, a sidewall portion defining the second section of the handle cavity bulges, allowing the gas to flow into the third section and the first section of the handle cavity.

Such a gas filling device may be arranged at a gas filling station of a filling machine comprising a station arranged in series, comprising said gas filling station and a filling station for supplying a liquid product to a product cavity of a container.

Such a filling machine is described, for example, in WO 2009/041909. The containers are moved intermittently to stations arranged in series and operating in parallel. The containers are thus moved step by step from one station to the next, one container being processed at one station while other containers are being processed at other stations.

For obvious reasons it is desirable for a filling machine to have a high throughput.Since the stations of a filling machine operate in parallel, the station requiring the longest operating time will determine the throughput of the filling machine.

Therefore, in order to ensure that the gas filling station does not constrain the production capacity of the filling machine, the gas filling operation must be performed at high speed and should not require more time than the filling operation at the filling station. However, the process of filling the handle cavity with gas by supplying gas through an inlet provided in the side wall of the container is a somewhat random process, especially at high production speeds, and in some cases it has proven difficult to achieve high reliability in the gas filling process at high production speeds, resulting in an unacceptably high failure rate, with some handle cavities being overfilled to the point of bursting.

Therefore, there is a need for an improved method for handling containers of the collapsible type in a filling machine comprising a filling station and a gas filling station.

Summary of the Invention

In view of the above, an object of the present invention is to provide a method for processing containers of the collapsible type in a filling machine having stations arranged in series, including a filling station and a gas filling station.

A further object is to provide such a method which enables gas filling at high speed and with relatively low failure rates.

Another object is to provide such a method which enables high-speed production and eliminates or at least substantially reduces the risk of overfilling the handle cavity.

These objects, as well as other objects that will be apparent from the following description of the invention, are fully or at least partially achieved by a method for handling containers of the collapsible type in a filling machine. Embodiments result from the claims dependent on the main claim.

More specifically, a method is provided for processing collapsible containers in a filling machine comprising a series of stations, including a filling station and a gas filling station. Each container comprises two flexible, opposing sidewalls defining a product chamber connected to an environment via a filling conduit and a separate handle chamber connected to the environment via an inlet provided in one of the two sidewalls. The method comprises intermittently moving the containers to the series of stations, wherein at the filling station, a liquid product is supplied to the product chamber using a filling tube inserted into the filling conduit of the container, and at the gas filling station, gas is supplied to the handle chamber using a nozzle applied above the gas inlet. The filling station and the gas filling station are operated such that the liquid product is supplied to the product chamber of one container located at the filling station while gas is supplied to the handle chamber of another container located at the gas filling station. The step of supplying gas at the gas filling station comprises providing a first gas flow at a first pressure, transmitting the first gas flow from the nozzle to the handle chamber via the inlet, and then providing a second gas flow at a second pressure lower than the first pressure, transmitting the second gas flow from the nozzle to the handle chamber via the inlet, to establish a target pressure within the handle chamber corresponding to the second pressure.

Accordingly, an improved method for handling collapsible containers in a filling machine comprising serially arranged stations is achieved. By intermittently moving the containers to serially arranged stations operating in parallel, high production capacity can be achieved. Furthermore, it is ensured that the step of supplying gas at the gas filling station can be carried out with high reliability and at a high speed without constraining the production capacity of the filling machine. By transmitting a first airflow at a first pressure, the first airflow can be provided at a sufficiently high pressure to quickly introduce air into the handle cavity. Furthermore, by subsequently providing a second airflow at a pressure corresponding to a target pressure, it is ensured that the handle cavity is filled with a sufficient amount of gas without the risk of overfilling the handle cavity, which would result in the risk of rupture or bursting of the pipe. Therefore, the first airflow can be used as a pressure shock to inflate the handle cavity, while the second airflow completes the gas filling. As a result, a method for handling containers is provided that can operate at high speed and with a very low failure rate.

According to one embodiment of the inventive method, during the step of providing the first airflow, the amount of gas delivered to the handle cavity may be sufficient for inflation, but insufficient to reach the target pressure. This eliminates the risk of overinflating the handle cavity. The amount of gas delivered to the handle cavity during the step of providing the first airflow may correspond to 5-75 weight percent of the total amount of gas delivered to the handle cavity during both the step of providing the first airflow and the step of providing the second airflow.

The first gas stream can be supplied at a first pressure in the range of 1-7 bar, more preferably at a first pressure in the range of 1.8-3.5 bar above atmospheric pressure. The second gas stream can be supplied at a second pressure in the range of 0.3-2 bar, more preferably at a second pressure in the range of 0.5-1.0 bar above atmospheric pressure.

According to another embodiment of the inventive method, it may further include sealing the handle cavity once the target pressure has been reached. This sealing may be performed using a sealing jaw having a heatable sealing member and a non-heatable portion having low thermal conductivity, wherein the sealing jaw engages the handle cavity to provide a seal that captures gas filling the handle cavity, and wherein the non-heatable portion of the sealing jaw is positioned facing the pressurized side of the handle cavity. Accordingly, during formation of the seal, exposure of the pressurized handle cavity to the heatable sealing member is avoided, thereby providing a more reliable seal of the gas-filled handle cavity.

Generally, all terms used in the claims are intended to be interpreted according to their ordinary meaning in the technical field, unless expressly defined otherwise herein. All references to "an/the [element, device, component, tool, step, etc.]" are to be interpreted openly as referring to at least one example of that element, device, component, tool, step, etc., unless expressly stated otherwise. The steps of any method disclosed herein do not have to be performed in the exact order disclosed, unless expressly stated otherwise.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and further objects, features and advantages of the present invention will be better understood from the following illustrative and non-limiting detailed description of preferred embodiments of the invention, with reference to the accompanying drawings, in which like reference numerals will be used for similar elements, and in which:

Figure 1 is a side view of a container of the collapsible type suitable for use with the method according to the present invention.

FIG. 2 is a schematic diagram of a filling machine comprising stations arranged in series.

FIG3 is a schematic diagram of a gas filling station of a filling machine.

FIG. 4 is a perspective view of an embodiment of a nozzle of a nozzle unit included in a gas filling station.

5 is a perspective view of an embodiment of a docking portion of a nozzle unit included in a gas filling station.

6a - 6d are schematic diagrams illustrating an embodiment of the inventive method for processing containers of the collapsible type in a filling machine comprising stations arranged in succession.

7a-7b are schematic diagrams illustrating a gas filling operation according to an embodiment of the inventive method.

8a-8c are cross-sectional views of a nozzle and an abutment of a nozzle unit for clamping and gas-filling a handle cavity of a container at different steps during a gas-filling operation.

9 is a perspective view illustrating steps according to an embodiment of the inventive method of sealing a gas-filled handle cavity of a container.

FIG10 is a cross-sectional view taken along line A-A in FIG9.

11 is a perspective view of a collapsible container provided with a seal that captures gas supplied to its handle cavity.

DETAILED DESCRIPTION

With reference to Figure 1, an example of a collapsible container 1 is shown to which the apparatus and method according to the present invention can be applied. The container can be used as a prefabricated container suitable for being filled and sealed in a filling machine. Alternatively, the container can be fully or partially produced in the filling machine.

The container is particularly intended for products in the form of liquid foods, such as milk, water, fruit drinks, juice or wine, but it may of course also be intended for some other form of product or for other purposes.

The container comprises three flexible walls, two of which constitute side walls 2, and the third constitutes bottom wall 3. The walls join along a connection 4 to define a product chamber 5. Walls 2 and 3 are made of a bendable and flexible material, which means that the volume of product chamber 5 depends on the relative distance between walls 2 and 3. The volume of product chamber 5 is therefore directly dependent on the fill rate of container 1. In other words, the container is a collapsible type, also known as a bag-type package.

The walls 2, 3 of the container 1 are preferably joined by welding at the connection 4. Other joining methods such as gluing are also conceivable.

The container 1 shown has an opening 6 formed as a mouth at its upper front end. To open the container 1, the outer end of the opening 6 is separated, thereby placing the product chamber 5 in contact with the surrounding environment. The outer end can be separated, for example, by cutting or tearing off. The container 1 can thus be emptied in its filled state using a pouring motion similar to that of a jug.

Generally, it is desirable for the selected container material to consist of a multilayer film, comprising a core layer based on a mineral filler and a polyolefin adhesive. It will be appreciated that other materials and layers are also possible, such as a gas barrier layer or a light barrier layer.

At the rear end of the container 1 , a handle cavity 7 is intended to be filled with gas to form the handle shown. The handle cavity 7 is defined by two side walls 2 and a surrounding connection portion 4.

In the embodiment shown, the handle cavity 7 has a single cavity design with three sections that are all interconnected. The first section 8 includes a portion that is intended to form the actual handle. The first section 8 is therefore a section that gives the desired function of the example as shown and described in the complete container, which consists of a handle or it provides some other function, such as a reinforcement effect. The third section 9 is directly connected to the first section 8 and constitutes a narrow duct that will be described below. The second section 10 is directly connected to the third section 9. In its simplest form, the second section 10 consists of an area defined by a portion of two opposing side walls 2 with an inlet 11 in the form of a hole in one side wall 2. The inlet 11 therefore constitutes the entrance to the handle cavity 7, through which the handle cavity 7 is connected to the environment before being filled with gas and sealed.

As mentioned above, the third section 9 constitutes a narrow conduit. Its main function is to form a surface on which the means for sealing the conduit after gas filling can be placed.

Third section 9 also serves to hold container 1 for the purpose of transferring it from a gas filling station where handle cavity 7 has already been filled with gas. The handle cavity can be sealed during this transfer, or it can be transferred to a station where handle cavity 7 is sealed, thereby capturing the supplied gas. The cross-sectional area of third section 9 is significantly smaller than that of first section 8. In this context, cross-sectional area refers to the area formed between the side walls transversely to the longitudinal direction of the handle cavity.

The third section 9 and the second section 10 of the handle cavity 7 may be provided with an embossed surface (not shown) on the inner side thereof. The embossed surface may facilitate separation of the associated side wall portion associated with gas filling.

The handle cavity 7 having three sections 8, 9, 10 is oriented in the illustrated embodiment in such a manner that the second section 10 is disposed adjacent the upper portion of the container 1, i.e., the portion through which the product cavity 5 of the container 1 is intended to be filled with its contents. However, it will be appreciated that the handle cavity 7 can be oriented exactly as desired.

As mentioned above, handle cavity 7 is intended to be filled with air, thereby forming a handle for the container. The gas preferably refers to air, but other gases may of course be used. Handle cavity 7 has a geometry and fill ratio that form an easy-to-grip handle in its unexpanded state. This handle also contributes to the considerable rigidity of container 1 through its geometry and gas filling.

The container 1 has a filling channel 12 in the center of its upper part, through which the cavity 5 of the container 1 can be filled with a liquid product. When the container 1 is prefabricated and intended to be provided as a blank to a filling machine, as in the embodiment shown, the filling channel 12 can be closed by an end seal 13 to be removed before filling. After filling is completed, the filling channel 12 is sealed again.

In Figure 2, to which reference is now made, a filling machine 20 is schematically shown for processing containers 1 of the type described above, i.e. of the collapsible type. The illustrated part of the filling machine 20 is intended for the processing of containers by intermittently feeding them in a transverse direction.

The filling machine 20 comprises stations arranged in series, including a filling station S3 and a gas filling station S5. Each station may comprise a not shown fixture for holding the container 1 at the associated station. It will be appreciated that the station may be integrated in the fixture.

In the embodiment shown, the stations arranged in series include: an input station S1 for receiving containers, for example, from a section of a filling machine where the containers have been supplied edge-to-edge; an opening station S2 for opening the filling channel of the container; a filling station S3 for filling the product cavity of the container; a sealing station S4 for sealing the filled product cavity of the container; a gas filling station S5 for inflating the handle cavity of the container; and an output station S6 from which the container is transferred for subsequent processing. Containers 1 of the type described above with reference to FIG. 1 are shown at each station.

The opening station S2 may include a pair of suction cups 21 arranged to engage opposing side wall portions defining the filling duct and to separate the opposing side wall portions by separation of the suction cups 21 .

The filling station S3 may comprise a filling pipe 22 connected to a source 23 of liquid product via a product valve 24. The filling pipe 22 may be inserted into the filling pipe of the container 1 once the filling pipe has been opened at the preceding opening station S3.

Sealing station S4 may include a pair of sealing jaws 25, at least one of which includes a first sealing member 26, which may be permanently heated. Sealing jaws 25 may be configured to engage a container 1 located at sealing station S3, such that once the product cavity has been filled at the previous filling station S3, first sealing member 26 provides a seal that closes the filling channel and thereby seals the product cavity. Sealing jaws 25 may be integrated into or form part of a fixture that holds container 1 at sealing station S4.

In the illustrated embodiment, the gas filling station S5 includes a nozzle unit 27 connected to two pressurized gas sources 28. The nozzle unit 27 includes a control unit 29, a nozzle 30, and a docking portion 31. The nozzle 30 is configured to movably abut the docking portion 31, thereby clamping the container 1 and applying the nozzle 30 above the inlet of the handle cavity. The nozzle 30 and docking portion 31 can be integrated into a fixture that holds the container in the gas filling station S5. The gas filling station S5 will be described in more detail below.

The filling machine 20 further comprises a transfer unit 40. The illustrated embodiment of the transfer unit 40 is arranged to intermittently transfer the containers 1 in the transverse direction in the direction indicated by the arrow P1 and to grip the containers 1 at their upper part so that they are suspended in the transfer unit 40. The containers are moved intermittently to the stations arranged in succession and thus move step by step from one station to the next.

The transfer unit comprises gripping members 41 for taking a container 1 from a station situated upstream and for transferring it to an adjacent station situated downstream.

The transfer unit 40 is carried by a rotatable mount 42. Each mount 42 comprises an arm 43, the end 44 of which, facing away from the center of rotation C of the mount 42, is pivotally carried in a bearing in the transfer unit 40. This allows a circular motion to be imparted to the transfer unit 40, more specifically, each gripping member 41 to cyclically move along a circular, annular path between a pick-up position and a delivery position.

Each gripping member 41 may comprise a pair of jaws which are movable against each other so as to pinch the upper portion of the container.

The transfer unit 40 may, for example, include pneumatic, hydraulic and/or mechanical means (not shown) for the operation of a pair of jaws.

In the drawings, the clamping member 41 is shown in an open position.

The gripping member 41 configured to retrieve the container from the gas filling station S5 and transfer it to the output station S6 may, as in the illustrated embodiment, further include a gas sealing unit 46 integrated therein. The gas sealing unit 46 includes a sealing member 47 configured to provide the container 1 with a seal that captures gas introduced into the handle cavity 7. Alternatively, the gas sealing station may be integrated into the gas filling station, or a further station for providing a seal may be provided as an adjacent station located downstream relative to the gas filling station S5.

The gas filling station S5 will now be described in more detail with reference to FIG. 3 , which schematically illustrates an apparatus 50 provided at the gas filling station S5 for gas filling of handle cavities of containers of the type described above.

The illustrated embodiment of the apparatus 50 comprises a nozzle unit 27 connected to two pressurized gas sources 28. The nozzle unit 27 comprises a docking portion 31, a nozzle 30 and a control unit 29.

The nozzle 30 is connected to a control unit 29 which in turn is connected to two pressurized gas sources 28 .

The nozzle 30 and the docking portion 31 are movable towards each other so that the second section of the handle cavity of the container can be clamped therebetween, with the inlet of the second section facing the nozzle 30. It is understood that one of the nozzle 30 and the docking portion 31 can be stationary.

An embodiment of the nozzle 30 and the interface 31 is shown in Figures 4 and 5 to which reference will now also be made.

The nozzle 30 disclosed in FIG4 comprises a cylindrical body 51 having a central conduit 52 terminating in an outlet 53 having a chamfered peripheral edge 54 for delivering gas to the handle cavity of the container. The outlet 53 is surrounded by an annular groove 55, and an engagement surface 56 is provided radially outside the annular groove 55. A peripheral collar 57 surrounds the engagement surface 56.

The docking portion 31 shown in Figure 5 comprises a body 60 having a recess 61 provided in a top surface thereof. The recess 61 is partially surrounded by a raised, C-shaped docking surface 62 defining a side opening 63 for said recess 61 .

The apparatus 50 further comprises a moving means (not shown) for relative movement of the nozzle 30 and the docking portion 31 toward each other so that the engagement surface 56 of the nozzle 30 abuts the engagement surface 62 of the docking portion 31 for gripping the container. Such moving means may comprise pneumatic, hydraulic, electronic or mechanical means, etc.

The apparatus 50 is configured for gas filling of the handle cavity of the container via the nozzle unit 27, which is configured to deliver gas to the handle cavity via the inlet to establish a target pressure _PT therein and thereby expand the handle cavity. The container is manufactured from a container material having sufficient strength for the handle cavity to retain its volume and not expand further once the target pressure has been reached.

More specifically, the nozzle unit 27 is configured to expand the handle cavity ₇ of the container 1 described above with reference to Figure 1 by supplying a first air flow _Q1 at a first pressure _P1 and then supplying a second air flow _Q2 at a second pressure _P2 lower than the first pressure P1 and corresponding to the target pressure _PT .

To this end, a control unit 29 of the nozzle unit 27 is configured to control the supply of gas. In the illustrated embodiment, the control unit 29 is configured to selectively connect the nozzle 30 to two independent pressurized gas sources 28. A first of the pressurized gas sources 28 is configured to supply a first gas flow _Q1 at a first pressure _P1 , and a second of the pressurized gas sources 28 is configured to supply a second gas flow _Q2 at a second pressure _P2 . As a non-limiting example, the control unit 29 may include a valve member configured to switch between the first and second gas flows in response to a given parameter, such as a signal generated according to a predetermined schedule or a signal from a processor, a sensor, or the like.

The control unit 29 may alternatively be connected to a single gas source and further comprise a controller or regulator arranged to convert an electrical input signal into a proportional output pressure, thereby delivering the first and second gas flows at said first and second pressures respectively.

The nozzle unit 27 is arranged to deliver the first gas flow _Q1 for a period of time required to supply a volume of gas sufficient to expand the handle, i.e. the first section 8 of the handle cavity 7, to an expanded state but insufficient to reach the target pressure _PT therein.

Subsequent delivery of the second air flow _Q2 at the second pressure _P2 results in the establishment of the target pressure _PT within the handle. Once the target pressure _PT has been reached, a state of equilibrium will result if leakage is prevented, as the supply of the second air flow _Q2 at the second pressure _P2 corresponding to the target pressure _PT is insufficient to further expand the volume of the handle. It has been found that leakage is effectively eliminated by the design of the nozzle 30 and the docking portion 31, such as described above with reference to Figures 4 and 5.

The amount of gas delivered to the handle cavity 7 during the step of providing the first airflow _Q1 may correspond to 5-75 weight percent of the total amount of gas delivered to the handle cavity 7 during the steps of providing the first airflow _Q1 and providing the second airflow _Q2 . To speed up the gas filling operation, it is advantageous to deliver as much gas as possible during the step of providing the first airflow _Q1 , with an upper limit of 75% being used to ensure that the handle cavity 7 is not overfilled with gas during this step. If the time available for the gas filling operation permits, it may be advantageous to deliver a lower amount of gas during the step of providing the first airflow _Q1 to further ensure that overfilling does not occur.

An embodiment of the inventive method for processing containers of the collapsible type in a filling machine 20 of the type described above with reference to FIG. 2 will now be described with reference to FIG. 6 a - d .

According to the inventive method, containers are intermittently moved to stations arranged in series. Thus, each container is gradually moved from each station to the next. The stations are arranged to operate in parallel, i.e., one container is processed at one station while another container is being processed at another station.

6a, the transfer unit 40 has been operated by rotating the mounting 42 so that the gripping members 41 have traveled along their respective circular paths to the associated upstream station. Likewise, the gripping members 41 have moved to the closed position so as to grip the container 1 located at each station.

Each clamping member 41 acquires the associated container 1 at each station, so that an unfilled container 1 provided in a flat state has been acquired at the input station S1; a container 1 with an open filling pipe has been acquired at the opening station S2; a container 1 already filled with a liquid product has been acquired at the filling station S3; a container 1 already provided with a seal for closing the filling pipe has been acquired at the sealing station S4; a container 1 with a handle cavity 7 after gas filling has been acquired at the gas filling station S5.

In Figure 6b, the mounting member 42 has been rotated in the direction indicated by arrow P2, thereby transferring each retrieved container 1 along its own circular path toward its associated, adjacent, downstream station. As indicated, the station has been operated to allow each container to be retrieved and also to allow new containers to be retrieved. Consequently, the suction cup 21 has been released and separated; the sealing jaws 25 have been separated; and the nozzle 30 has been separated from the docking portion 31. As described above, while the gripping member 41 transfers the container 1 from the gas filling station S5 to the output station S6, the gas sealing unit 46 integrated in the associated gripping member 41 provides a seal for the container 1, capturing gas introduced into the handle cavity 7.

In Figure 6c, the mounting 42 has been further rotated in the P2 direction, thereby positioning the gripping member 41 at the associated downstream station. At each station, a gripper (not shown) is then activated for holding the container 1 transferred to the respective station.

Furthermore, the sealing provided by the gas sealing unit 46 integrated in the gripping member 41 according to the embodiment shown is completed when the container 1 transferred by said gripping member 41 reaches the output station S6.

When the grippers, not shown, have been activated for holding the containers at the respective stations, the gripping members 41 can be opened to complete the transfer and transport of the associated container.

By further rotating the mounting 42 in the direction P2, as shown in Figure 6d, the gripping member 41 can be moved towards the associated pick-up position to start a new acquisition-transfer-delivery cycle while associated operations are performed at the various stations. As can be seen, a new container has been provided at the input station S1.

According to the inventive method, the associated operations include at least the filling of the product cavity at the filling station and the gas filling of the handle cavity at the gas filling station. As mentioned, these operations are performed in parallel.

At filling station S3, liquid product is delivered to the product chamber of container 1 via a filling tube 22 inserted into the filling conduit of container 1. The liquid product is supplied from a liquid product source 23 using a product valve 24. Product valve 24 may be time-controlled. Alternatively, the valve may be operated based on input data received from a flow meter or any other input data indicating the amount of liquid product transferred to the product chamber of container 1.

As mentioned above, the handle cavity 7 of the container 1 at the gas filling station S5 is filled with gas, while the product cavity of the container 1 at the filling station S3 is filled with a liquid product. The gas filling of the handle cavity 7 must be performed with high reliability and high speed. The time available to complete the gas filling operation is determined by the time required to complete the liquid product filling operation to ensure that the gas filling operation does not limit the production capacity of the filling machine.

In order to ensure high reliability and high speed of the gas filling operation, the gas filling operation is performed in a two-step process, which will now be described with reference to Figures 7a, 7b and 8a-c.

In FIG7a , a portion of a container 1 of the type described above is positioned between the nozzle 30 and the docking portion 31 of the apparatus 50. As is apparent from the figure, the container 1 is filled with product at this stage, but it is understood that the gas filling of the handle cavity 7 may alternatively be performed before the container is filled with product. Thus, the gas filling station S5 may be located upstream relative to the filling station S3.

The nozzle 30 and the docking portion 31 are shown in more detail in FIG. 8 a , which also illustrates the orientation of the second section 10 of the container 1 with its inlet 11 leading to the handle cavity facing the nozzle 30 .

8b, the nozzle 30 and the docking portion 31 have come together to clamp the container 1 with the engagement surface 56 of the nozzle 30 pressed against the docking surface 62 of the docking portion 31. The docking portion 31 is arranged so that its side opening 63 is aligned with the third section 9 of the handle cavity 7 (not shown).

FIG7b illustrates the nozzle 31 and docking portion 30 operating together to fill the handle cavity 7 with gas. As previously explained, the nozzle unit 27 is configured to initially deliver a first gas flow _Q1 at a first pressure _P1 , thereby expanding the handle cavity 7 but insufficient to achieve a target pressure _PT within the handle cavity 7, and subsequently deliver a second gas flow _Q2 at a second pressure _P2 corresponding to the target pressure _PT , for establishing the target pressure _PT within the handle cavity 7. The delivery of gas is controlled by the control unit 29. The first pressure _P1 may be in the range of 1-7 bar, or more preferably, in the range of 1.8-3.5 bar above atmospheric pressure. The second pressure _P2 may be in the range of 0.3-2 bar, more preferably, in the range of 0.5-1.0 bar above atmospheric pressure.

In FIG8c, the nozzle 30 and the docking portion 31 are disclosed as holding the container 1 during gas delivery. The combination of the recess 61 provided in the docking portion 31 and the chamfered peripheral edge 54 provided in the form of a recess in the nozzle 30 surrounding the outlet 53 of the central conduit 52 causes the opposing sidewall portions of the container 1 defining the second section 10 of the handle cavity 7 to bulge in opposite directions in response to the delivery gas entering the handle cavity 7 via the inlet 11. The nozzle 31 may be provided with an additional conduit (not shown) connecting the annular groove 55 to the surroundings to further ensure that the sidewall portion facing the nozzle 31 bulges in the direction toward the nozzle 31 in response to the delivery gas.

As described above, the third section 9 of the handle cavity 7 is aligned with the side opening 63 in the docking portion 31 , so gas entering the second section 10 of the handle cavity 7 freely enters and expands the third section 9 and further advances to the first section 8 .

As described above, the nozzle unit 27 is configured to initially deliver a first airflow _Q1 at a first pressure _P1 and subsequently deliver a second airflow _Q2 at a second pressure _P2 lower than the first pressure _P1 . The first airflow _Q1 is used to expand the handle cavity 7, and the second airflow _Q2 is used to establish a target pressure _PT in the handle cavity 7.

As a result, expansion of the handle cavity 7 at a high speed is achieved with the first high-pressure air flow _Q1 serving as a pressure shock.

The risk of rupture or bursting of the handle cavity 7 due to overfilling is eliminated by the subsequent supply of the second air flow _Q2 at a second pressure _P2 corresponding to the desired target pressure _PT .

The volume of the handle cavity 7 in the non-expanded state may be in the range of 5-10 cm ³ , the first airflow Q ₁ may be delivered for a time period in the range of 20-150 ms, and the time required to establish the target pressure _PT by the second airflow Q ₂ may be in the range of 0.2-1 s.

In experiments conducted on a container with a handle cavity having an expansion volume of 7 ^cm³ and using a device for gas filling using a nozzle and a docking station as described above, a first gas flow _Q1 was delivered at 5 bar for 50 ms, followed by a second gas flow _Q2 at 1 bar. The success rate of the gas filling process amounted to 99.9%.

Once the target pressure _PT has been reached, the handle cavity 7 is sealed by the gas sealing unit 46.

9 and 10 schematically illustrate steps according to an embodiment of the inventive method of sealing a handle cavity by means of a sealing unit 46. The sealing unit 46 comprises a sealing jaw 48 which is movable for engagement with the container 1, thereby providing a seal 14 that captures gas delivered to the handle cavity 7. More specifically, the sealing jaw 48 is arranged to engage the third section 9 of the handle cavity 7, thereby providing a seal 14 that extends across said third section 9, which is illustrated in FIG. 11 .

The sealing jaw 48 includes a heatable sealing member 47 and a non-heatable portion 49 arranged side by side. The non-heatable portion 49 is made of a material with low thermal conductivity, such as polyetheretherketone (PEEK). The non-heatable portion 49 is oriented so that it faces the pressurized side of the handle cavity 7, as shown in FIG10 .

The seal 14 is completed by the sealing member 47, and the non-heatable portion 49 ensures that the seal 14 is not exposed to the pressurized gas while being formed.

The gas sealing unit 46 may be arranged as described above in a transfer unit arranged for taking containers from a gas filling station. Alternatively, the sealing unit may be arranged in the gas filling station or in a station located downstream independently of the gas filling station.

It will be appreciated that the invention is not limited to the embodiments shown. Several modifications and variations are therefore conceivable within the scope of the invention, which is therefore defined solely by the appended claims.

Claims (9)

1. A method for processing a collapsible container (1) in a filling machine (20), the filling machine (20) comprising consecutively arranged stations (S1, S2, S3, S4, S5, S6), the consecutively arranged stations (S1, S2, S3, S4, S5, S6) including a filling station (S3) and a gas filling station (S5), Each container (1) includes two flexible opposing sidewalls (2), which define a product cavity (5) in communication with the environment via a filling conduit (12) and a separate handle cavity (7) in communication with the environment via an inlet (11) disposed in one of the two sidewalls (2), the method comprising: The container (1) is moved intermittently to the continuously set stations (S1, S2, S3, S4, S5, S6); At the filling station (S3), liquid product is supplied to the product chamber (5) via the filling tube (22) inserted into the filling pipe (12) of the container (1); and At the gas filling station (S5), gas is supplied to the handle chamber (7), including: The nozzle (30) is applied above the inlet (11) by the relative movement of the nozzle (30) and the docking part (31) toward each other, thereby clamping the container (1) with the inlet (11) facing the nozzle (30); and Gas is then supplied through the nozzle (30). The filling station (S3) and the gas filling station (S5) are operated such that a liquid product is supplied to the product chamber (5) of one of the containers (1) located at the filling station (S3), while gas is supplied to the handle chamber (7) of the other container (1) located at the gas filling station (S5), characterized in that the step of supplying gas at the gas filling station (S5) includes: A first airflow ( _Q1 ) is provided at a first pressure ( _P1 ), and the first airflow ( _Q1 ) is transmitted from the nozzle (30) to the handle chamber (7) via the inlet (11); and A second airflow ( _Q2 ) is then provided at a second pressure ( _P2 ) lower than the first pressure ( _P1 ), and the second airflow ( _Q2 ) is transmitted from the nozzle (30) to the handle chamber (7) via the inlet (11) to establish a target pressure ( _PT ) corresponding to the second pressure ( _P2 ) within the handle chamber (7). 2. The method according to claim 1, wherein during the step of providing the first airflow ( _Q1 ), the amount of air transmitted to the handle chamber (7) is sufficient for its expansion but insufficient to reach the target pressure ( _PT ). 3. The method according to claim 1 or 2, wherein during the step of providing the first airflow ( _Q1 ), the amount of air transmitted to the handle cavity (7) corresponds to 5-75% by weight of the total amount of air transmitted to the handle cavity (7) during the steps of providing the first airflow ( _Q1 ) and providing the second airflow ( _Q2 ). 4. The method according to claim 1 or 2, wherein the first airflow ( _Q1 ) is supplied at the first pressure ( _P1 ) in the range of 1-7 bar. 5. The method of claim 4, wherein the first airflow ( _Q1 ) is supplied at a first pressure ( _P1 ) in the range of 1.8-3.5 bar above atmospheric pressure. 6. The method according to claim 1 or 2, wherein the second airflow ( _Q2 ) is supplied at the second pressure ( _P2 ) in the range of 0.3-2 bar. 7. The method of claim 6, wherein the second airflow ( _Q2 ) is supplied at a second pressure ( _P2 ) in the range of 0.5-1.0 bar above atmospheric pressure. 8. The method according to claim 1 or 2, further comprising sealing the handle chamber (7) once the target pressure ( _PT ) has been reached. 9. The method of claim 8, wherein the seal is performed using a sealing claw (48) having a heatable sealing member (47) and a non-heatable portion (49) having low thermal conductivity, wherein the sealing claw (48) engages with the handle cavity (7) to provide a seal (14) for trapping gas filling the handle cavity (7), and wherein the non-heatable portion (49) of the sealing claw (48) is configured to face the pressurized side of the handle cavity (7).