HK1133625B - A container blank intended for a container of a collapsible type - Google Patents

Description

Container blank for a container of a collapsible type

The present application is entitled "method and apparatus for gas filling and sealing of a duct that is to be filled with gas and positioned in a container of a collapsible type; and a container blank "comprising the catheter, divisional application of the invention patent application having international application No. PCT/SE2004/001386, national application No. 200480028619.8, and international application No. 2004/29/9/2004.

Technical Field

The present invention relates to a method and a device for gas filling and sealing of a duct intended to be positioned in a container of a collapsible type. The invention also relates to a container blank having a duct to be filled with gas.

Background

It has long been known to use containers of the collapsible type, for example for food or consumable substances, such as sanitary products and detergents. The contents may be in liquid or powder form.

By a container of a collapsible type is meant that the container of the type comprises thin flexible walls which are connected together in a connecting portion so as to define a compartment. The volume of the compartment depends on the relative distance between the walls, which means that the volume depends on the filling rate of the container.

Containers of this type may have a number of different handle shapes, one handle shape being shown in WO 99/41155. The handle forms an aperture through which a user's hand can be inserted so that the container can be grasped and handled like a jug.

In SE518406 a container of a corresponding type has also been developed such that a gas-filled duct is arranged in the connecting portion along at least one side of the container. The main purpose of such a gas-filled duct is to increase the stability of the container and also to make it more comfortable to grasp. The gas-filled duct shown in the document is arranged to be filled at the same time as the container is filled with contents. But there is no description of how the gas filling is performed or how the device is designed.

Containers of the collapsible type are usually filled through a duct/opening which is defined by two opposite walls of the container. The filling takes place with the container in an upright position, in which case the filling nozzle can act essentially in a vertical direction and be introduced into the duct between the two walls. The method works well when applying a fluid in liquid form. However, this method causes a great problem when a fluid in the form of a gas is applied, because it is difficult to provide a gas-tight seal around the nozzle while supplying the gas. A further problem arises when the gas-filled duct is sealed.

The solution to this problem is that the duct is filled with gas through a one-way valve integrated in the container. This technique is very expensive for use with mass produced containers, such as food containers where the duct is filled only once.

There is therefore a need for a method and a device for gas filling of the duct in a collapsible container, irrespective of the purpose of the gas-filled duct. It is also desirable to develop the structure of the duct so that it can be easily filled with gas and easily sealed in industrial use. It will be appreciated that the purpose of the duct is not to be used for refilling.

Object of the Invention

It is an object of the present invention to provide a device and a method for gas filling a duct in a container of a collapsible type.

The method and apparatus are easy to use, can be produced at high speed, and have high reliability.

It is a further object of the invention to provide a container blank with a duct which is suitably designed for use in the device and method.

The conduit should be of such a construction that no new material or components, for example in the form of one-way valves, have to be added to the container blank.

Disclosure of Invention

To achieve at least one of the above objects and other objects, which will become apparent from the description below, a method, a device and a container blank having the features stated in claims 1, 5 and 19 are provided according to the invention.

More specifically, the invention provides a method of gas filling and sealing of a duct to be filled with gas and positioned in a container of a collapsible type, said duct being defined by two opposite side walls which are joined along a connecting portion and comprising an inlet opening arranged in one of the side walls. The method is characterized by comprising: a portion of the container, which portion comprises said inlet, is clamped between a support and a gas module which is axially movable towards the support, so that one of the two side walls comprised in the duct is able to bulge in response to a gas flow supplied from the gas module and entering the duct through said inlet, so as to form a free passage into the duct for filling the duct with gas and to seal the duct after completion of the gas filling.

Thus, during gas filling, the container is clamped by clamping over the part of the container comprising the inlet opening, i.e. a part of the duct. Subsequently, gas is supplied to the conduit through a gas module acting in the clamping direction. Thus, both the clamping direction and the operating direction of the gas module are oriented more or less perpendicular to the extension direction of the conduit. One wall defining the conduit can project to provide free access to the conduit despite gripping over the portion of the vessel including the inlet. This method is very simple and advantageous in comparison with the prior art described above, in which the two side walls defining the duct and forming the inlet opening have to be separated, after which the nozzle for gas filling can be introduced into the duct in the longitudinal direction thereof, while the nozzle has a clamping effect on the duct in a direction perpendicular to the gas filling direction. The method of the invention does not require any one-way valve at all.

Preferably, said portion of the container is gripped by means of an axial movement of the nozzle and of an encapsulation device with respect to said support, which is arranged outside the container and is associated with the gas module.

Furthermore, it is preferred that the holder is formed with a recess at its side facing the container in order to allow said protrusion. The recess enables a portion of the side wall forming the conduit to bulge during gas supply, thereby forming a free passage into the conduit, although the portion of the container including the inlet to the conduit is clamped by clamping it just above the conduit.

After the gas filling is completed, the duct is preferably sealed by applying heat and pressure to the section of the duct abutting the abutment. Precisely, heat sealing is the best method because it is fast and does not require any additional supply of material. Moreover, the heat sealing provides a gas-tight seal in a simple manner.

According to another aspect, the invention relates to a device for gas filling and sealing of a duct to be filled with gas and positioned in a container of a collapsible type, said duct being defined by two opposite side walls connected along a common connecting portion, and the duct comprising an inlet arranged in one of the side walls. The device is characterized in that it comprises a support and a gas module which is axially applicable on the support so as to abut against a portion of the container and an inlet arranged in the portion, the gas module being arranged to fill the duct with gas through the inlet and to seal the duct after completion of the gas filling.

The structure of the device is very simple. The gas module enables the same operating direction to be used for all functions, i.e. holding the container, filling its duct with gas and subsequent sealing. The device does not require additional means on the container, for example in the form of a one-way valve or a separate inlet.

In a preferred embodiment, the gas module comprises a nozzle, which can be applied on the inlet, for supplying gas to the conduit. The encapsulation device is arranged to surround the nozzle and may be applied on the support to seal around the nozzle. The packing means will prevent unwanted gas leakage during the gas filling process.

The nozzle and the enclosing means may be arranged on a common unit in the form of a first piston rod comprising an inner bore for supplying gas to the conduit through the nozzle. The integrity of the connection between the gas source and the nozzle in the piston rod eliminates the need for a separate gas supply conduit that would require frequent maintenance due to the movement of the gas module relative to the support.

It is also preferred that the gas module comprises sealing means for disconnecting the inlet from the duct by sealing after filling the duct arranged in the container with gas. The sealing means preferably comprises a ram which is axially engageable with the heating jaw. Thus, the sealing is performed by a combination of pressure and heat, and causes at least the surface layers of the two opposite side walls defining the duct to fuse together. This seal will form an airtight seal of the conduit.

The heating chuck may be arranged outside the support. Alternatively, the carrier rod may be arranged outside the carrier. According to the chosen solution it is preferred that the ejector pin or the heated jaw is arranged as a second piston rod outside the first piston rod, which can simplify the control of the movement of the piston rod. When the heating jaw is arranged outside the support, the heating jaw may likewise be a heating jaw used when closing the duct means in the container through which the container is filled with its contents. This solution enables a very compact and space-saving apparatus to be used for manufacturing containers.

In a further preferred embodiment the first piston rod comprises an external lug which is engageable with the second piston rod for returning the second piston rod during the return stroke of the first piston rod. This makes the return stroke of the piston rod very simple and reliable.

Preferably the support comprises in its plane a groove for receiving a projection of the at least one side wall during filling of the duct with gas. This creates a free passage into the conduit through the inlet, although the container is clamped between the gas module and the support by a clamping effect on the conduit portion.

Preferably the support is made of a material having a low thermal conductivity. This is particularly suitable when the support is surrounded by a heated chuck. This eliminates the risk of the holder reaching a temperature at which the material of the container is thermally affected and causes undesired connections. It is also possible to provide the support with cooling means, for example in the form of cooling coils.

According to another aspect, the invention relates to a container blank intended for a container of a collapsible type, said container blank comprising a duct intended to be filled with gas and defined by two opposite walls joined along a common connecting portion. The container blank is characterized in that the duct comprises: a first portion which, after gas filling, provides a desired geometry in the container; a second portion contiguous with the first portion, the second portion having a cross-sectional area substantially smaller than the first portion; and a third portion contiguous with the second portion and including an inlet to the conduit.

This fact that the conduit is made in a large number of sections (where the second section has a significantly smaller cross-sectional area than the first section) means that the gas supplied to the conduit is able to expand the first section but not the second section. This means that the second portion is also substantially flat when the first portion is fully expanded. Thus, the sealing means arranged above the second portion need only vent a small amount of gas before the two opposing side walls of the duct are brought into full engagement between them to create a gas tight seal.

The first part should have a geometry that facilitates providing the desired technical function in the formed container, for example in the form of a comfortable handle forming rim or a stiffening duct.

Preferably, the inlet is an aperture formed in one of the side walls. Such an inlet construction is the simplest and does not require the addition of other materials or components, for example in the form of one-way valves.

Preferably, the third portion is arranged in connection with a duct means of the container blank, through which duct means the container blank is adapted to be filled with its contents. This means that the means for filling the duct with gas can be arranged in direct connection with the means for sealing the container after it has been filled with its contents. The location of the inlet in one side wall and the duct means seal which is normally created across the duct means that the two means can act in a common direction and even the movement of the two means can be coordinated as the sealing of the duct and the duct means is adapted to be done in a heated manner.

Drawings

The invention will now be described in more detail, by way of example, with reference to the accompanying drawings, which show preferred embodiments of the device and container blank.

Fig. 1 shows an example of a container of a collapsible type comprising a gas-filled duct forming a handle.

Fig. 2 shows a container blank corresponding to the container shown in fig. 1.

Fig. 3 schematically shows an embodiment of the device for filling a handle with gas. The device is shown in a non-driven state and a driven state, respectively.

Figure 4 shows a support for the device.

Detailed Description

Referring to fig. 1, there is shown an example of a collapsible container 1 to which the present apparatus and method will be applied.

The container will be used in particular for liquid food products such as milk, water, fruit juices or wine, but it may of course also be used for some other form of product or for other purposes.

The container comprises three flexible walls, two of which constitute the side walls 2 and the third of which constitutes the bottom wall 3. The walls are joined along a connecting portion 4 to define a compartment 5. The walls 2, 3 are made of a flexible material that is bendable, which means that the volume of the compartment 5 depends on the relative distance between the walls 2, 3. The volume of the compartment 5 is thus directly dependent on the filling rate of the container 1. In other words, the container is of a collapsible type.

The walls 2, 3 of the container 1 are preferably joined by welding at the connecting portion 4. Other methods of attachment, such as gluing, are also contemplated.

A handle 6 is arranged in the connecting portion 4 at the rear end of the container 1. The handle 6 comprises a gas-filled duct 7, which gas-filled duct 7 is defined by the connecting portion 4 and the side wall 2 of the container 1. Preferably, gas means air, but other gases, or even liquids, may be used. The handle 6 has such a geometry and filling rate that it facilitates the formation of an easily graspable rim (bead). The handle 6 also greatly increases the rigidity of the container 1 by its geometry and filling rate.

The container 1 has at its upper center a duct means 8 through which the container is filled. Filling is performed by separating a portion (not shown) in the upper part of the container and inserting a filling nozzle through the duct means into the container for filling the container. After the filling is completed the filling nozzle is removed and the container is then sealed again so that a new connecting portion is formed in the upper part of the container.

The shown container 1 has an opening portion 9 at its upper front end, which opening portion 9 is formed as a spout. To open the container 1, the outer ends of the opening portions 9 are separated, thereby putting the container 5 in communication with the environment. The outer end may be separated, for example, by cutting or tearing. The container 1 can thus be emptied like a kettle in a pouring motion.

It is generally desirable that the selected container material comprise a laminate comprising a core layer having a mineral-based filler and a polyolefin binder. It should be appreciated that other materials are possible.

Referring to fig. 2, there is shown a container blank 10 corresponding to the container 1 described in fig. 1.

At the rear end of the container blank 10 is shown a handle forming duct 7 to be filled with gas. The duct 7 is defined by two side walls 2 and a peripheral connecting portion 4.

The conduit 7 is divided into three portions, all of which are in communication with each other. The first part 12 comprises the part that will form the actual handle 6. Thus, the first portion 12 is the portion that produces the desired function in the formed container (whether it constitutes a handle or provides some other function, such as a stiffening effect, as in the illustrated and described examples). The second portion 13 is directly connected to the first portion 12 and constitutes a narrow duct (as will be described later). The third portion 14 is directly connected to the second portion 13. The third portion 14 is in its simplest form an area in one of the side walls 2 comprising an aperture 15. The hole 15 thus constitutes an inlet to the duct 7, through which the duct communicates with the outside environment before being filled with gas and sealed. Preferably, the third portion 14 has a surface area such that there is less positional deviation between the container blank 10 and the gas module for filling the duct 7 with gas.

As mentioned above, the second portion 13 constitutes a narrow duct. Its main function is to form a surface on which the means for sealing the duct can be arranged after the gas filling has been completed. The cross-sectional area of the second portion 13 is significantly smaller than the cross-sectional area of the first portion 12. In this case, the cross-sectional area means the area of the region between and consisting of the side walls, perpendicular to the longitudinal direction of the duct. This difference in cross-sectional area means that the gas pressure in the gas-filled and sealed duct 7 is able to expand the first section 12 to the desired volume, but not the second section 13. Thus, when the conduit 7 is filled with gas, the second portion 13 will constitute a substantially flat surface. Thus, the sealing of the duct across the second portion 13 can be performed without first having to expel a large amount of gas before the two opposite side walls 2 defining the duct 7 contact each other for sealing. To achieve this effect, the ratio of the cross-sectional area of the second portion 13 to the cross-sectional area of the first portion 12 will be at least 1: 150 when in a circular cross-sectional geometry.

The second and third portions 13, 14 of the conduit are preferably provided with an embossed surface (not shown) on their inner side. The embossed surface enables easy separation of the walls upon gas filling.

In the shown embodiment the duct 7 with the three sections 12, 13, 14 is oriented such that the third section 14 is arranged near the upper part of the container blank 10, i.e. the section through which the container blank is to be filled. It should be noted, however, that the guide tube 7 may be completely freely oriented.

The device 16 will now be described with reference to fig. 3, which device 16 will be used for filling the above-mentioned duct 7 with gas. Fig. 3 shows the device 16 in a non-actuated state and in an actuated state on either side of the ejector rod line in the figure.

Preferably, the device 16 constitutes a module in an apparatus (not shown) for manufacturing complete containers 1 from container blanks 10. In the apparatus, the module is preferably arranged to be directly connected to a module for heating the sealed duct means through which the containers are filled.

The device 16 comprises a support 17, which support 17 is shown in detail in fig. 4. In the embodiment shown, the abutment 17 comprises a circular rod 18. Of course, the seat 17 may have other suitable shapes. The abutment 17 has a recess 19 in its surface, the geometry of the recess 19 corresponding at least to the third portion 14 of the conduit 7, but preferably, as shown in fig. 4, to the third portion 14 and at least to a part of the second portion 13. The purpose of the recess 19 is to enable one side wall 2 of the duct 7 to project into the recess 19 during gas filling, so that, although the container 1 is clamped by clamping over a portion of the duct 7, an open channel is formed through which the duct 7 can be filled with gas. The recess 19 is preferably dimensioned such that there is a small positional deviation between the container and the gas module, which will be described later, when the duct 7 is filled with gas.

The support 17 should be made of a material with a low thermal conductivity, such as insulating glass fibre. Here, a lower thermal conductivity means that the temperature of the support 17 will prevent the material of the container against the support from melting even when the support is surrounded by a heated collet having a high temperature sufficient to melt the material for the container.

The support 17 may also comprise cooling means (not shown) in order to ensure a suitable temperature.

The gas module 20 is arranged axially with the support 17. The gas module 20 comprises a first piston rod 21. The first piston rod 21 has a nozzle (not shown) at its end facing the support 17, which is surrounded by a packing device 22. The nozzle is adapted to clamp the container 1 on the abutment 17 by clamping on that part of the container 1 which comprises at least the third portion 14, i.e. the bore constituting the inlet 15 of the conduit 7, by itself or in cooperation with some other clamping means (not shown), such as the enclosing means 20 or the first piston rod 21. As shown, the enclosure 22 can include a bellows or, for example, a sealing O-ring. During gas filling, the enclosing means 22 provides the desired sealing around the inlet 15 (which is used for filling the duct 7 with gas) when applied thereto.

The first piston rod 21 also includes an axial bore 23 through which the nozzle communicates with a source of compressed air (not shown) through a valve (not shown).

The gas module 20 further comprises a sealing device 24, which sealing device 24 comprises a mandrel 26, which mandrel 26 is axially engageable with the heating jaw 25. In the embodiment shown, the plunger 26 is arranged on a second piston rod 27, which second piston rod 27 concentrically surrounds the first piston rod 21. More specifically, the jack 26 is arranged at the end of the second piston rod 27 opposite the seat 17. It will of course be appreciated that the carrier rods 26 do not necessarily concentrically surround the first piston 21, but that they may also be arranged side by side. The carrier rod 26 may be designed in different ways, for example in the form of a flexible O-ring 28 as shown. During operation of the device, the ejector pin 26 serves to form an abutment surface against the protrusion 29 of the heating jaw 25. In the embodiment shown, the heating jaw 25 axially surrounds the seat 17. It should be appreciated that the O-ring 28 may be replaced by some other suitable device capable of cooperating with the heated cartridge 25.

The size of the protrusion 29 of the heating jaw 25 corresponds to the desired sealing surface 34 of the conduit 7, i.e. the seal that disconnects the first portion 12 of the conduit 7 from the rest of the conduit 7. The sealing surface 34 is shown in fig. 1. In the example shown, the annular projection 29 provides an annular sealing surface 34 in the third portion 14 around the inlet 15. The sealing surface 34 may also extend over a portion of the second portion 13. It will be appreciated that the sealing surface 34 has the same geometry as the abutment surface between the projection 29 and the O-ring 28.

In case the device 16 constitutes a module, which is arranged to be directly connected with a module of the duct means 8 for sealing the container 1, through which duct means 8 the container is filled with its contents, the heating jaw 25 may constitute a part of a heating jaw (not shown) for resealing the duct means 8.

Both the first piston rod 21 and the second piston rod 27 are connected at their ends facing away from the seat 17 via valves (not shown) to a pneumatic control system (not shown) for controlling the movement of the piston rods 21, 27.

To simplify the handling of the piston rods 21, 27, the first piston rod 21 has a lug 30 on its outside, which lug 30 is intended to cooperate with a complementary stepped recess 31 on the inside of the second piston rod 27, which recess concentrically surrounds the first piston rod 21.

The function of the device will be described below with reference to fig. 3.

A container (not shown in fig. 3), the duct 7 of which is ready to be filled with gas, is arranged between the two support surfaces 33a, 33b so that the inlet 15, i.e. the hole, in the third portion 14 and the second portion 13 coincide with the recess 19 in the seat 17. The container is oriented such that the inlet 15 faces away from the seat 17. The first piston rod 21 is driven so that it performs an outward stroke, such that the nozzle (not shown) and the enclosing means 22 grip a portion of the container, thereby bringing the enclosing means 22 into airtight contact with the container and bringing the nozzle against the inlet 15. In this position, the valve (not shown) leading to the bore 23 through the first piston rod 21 is open, thereby allowing gas to freely pass through the bore 23 and into the conduit 7 for inflating the conduit. The side wall 2 of the conduit 7 facing the seat 17 can project into the recess 19 when the gas is supplied, so that a free passage for the gas into the conduit is formed irrespective of the clamping of the container 1. The side wall portion of the third portion 14 surrounding the inlet 15 will have a tendency to spring back due to the hole from the inlet 15. When rebound occurs, gas is immediately able to escape to the space formed between the side walls 2 and pass to the rest of the duct 7. The separation of the side wall 2 during gas filling can be assisted by internal knurling on the inner walls of the second and third sections 13, 14. When the conduit 7, and in particular the first portion 12 thereof, expands to the required pressure and volume, the valve closes and the supply of gas through the bore 23 ceases.

Subsequently, the second piston rod 27 performs its outward stroke, and its plunger 26 in the form of an O-ring 28 presses the side wall 2 of the conduit 7 against the projection 29 of the heating jaw 25 at the desired time and with the desired pressure, thus forming a gas-tight welded joint and sealing the conduit 7. The resulting sealing surface 34 is schematically represented in fig. 1. The heating jaw 25 is preferably oriented to act on the second portion 13 and/or on the third portion 14. It is important that the inlet 15 is disconnected from the rest of the duct 7. The heating jaw 25 may be used together with an adiabatic release arrangement (not shown) arranged close to the heating jaw on the side facing the gas-filled duct 7. The release device is arranged at the same height as the heating jaw or slightly lower and serves to eliminate/reduce the internal gas pressure directly connected to the seal. This elimination or reduction of the internal gas pressure means that the temperature of the heating jaw is not as critical as for obtaining a gas-tight welded joint 32 for sealing the conduit 7.

After the desired time, the first piston rod 21 is stroked inwardly in order to return it to the original position. During this inward stroke the external lugs 30 of the first piston rod 21 will engage the internal stepped recesses 31 of the second piston rod 27, thus bringing the second piston rod 27 to an inward stroke, so that the second piston rod 27 also returns to its original position.

At this point the container 1 with the sealed gas-filled duct 7 can be freely detached from the device 16 for further transport/handling.

In the above-described device 16 and its function, the first piston rod 21 and the second piston rod 27 are arranged to operate in the same operating direction with respect to the seat 17 and the heating jaw 25 (which heating jaw 25 is arranged around the seat). It is understood that the same end result can be obtained by making minor variations of the device, which are within the scope of protection of the present invention.

In a variant, the heating jaw 25 can be arranged, for example, on a second piston rod 27, in which case the heating jaw 25 is applied to the seat 17 by movement of the second piston rod 27, and the plunger 26 cooperates with the heating jaw 25 in this seat 17.

In another variant, the first and second piston rods 21, 27 can be arranged to work in different operating directions from each other, with the heating jaw 25 and the ram 26 suitably arranged for movement.

The invention thus relates to a method and a device for gas filling and sealing of a duct 7 to be filled with gas and positioned in a container of a collapsible type. The invention also relates to a container blank 10 with a guide tube 7, which guide tube 7 is especially developed for the method and device.

The method and the device are developed in such a way that the functions related to the clamping of the container 1, the gas filling of the duct 7 and the sealing of the duct 7 can all be performed in one and the same operating direction, which enables a very space-saving device 16 to be formed. This means that the device 16 can be integrated into existing wrapping machines without difficulty. The device 16 has a very simple structure, which makes it simple to use, easy to maintain and has a high productivity.

A container blank 10 developed for the method and device 16 has a duct 7, which duct 7 can be easily filled with gas and can be sealed without having to add new material or new parts to the container, for example in the form of a one-way valve. Such a duct 7 can therefore easily be integrated into other types of container blanks.

It should be understood that the invention is not limited to the embodiments shown. Many variations and modifications are contemplated within the scope of the invention, which is therefore intended to be limited only by the appended claims.

Claims (3)

1. A container blank (10) for a container (1) of a collapsible type, said container blank (10) comprising a duct (7) which is to be filled with gas and which is defined by two opposite side walls (2) which are connected along a common connecting portion (4), characterized in that the duct (7) comprises:

a first portion (12) which, after gas filling, provides the desired geometry in the container (1);

a second portion (13) contiguous with the first portion (12), said second portion (13) having a cross-sectional area substantially smaller than the first portion (12); and

a third portion (14) contiguous with the second portion (13) and comprising an inlet (15) to the duct (7).

2. The container blank of claim 1, wherein: the inlet (15) is an aperture formed in one of the side walls (2).

3. The container blank of claim 1, wherein: the third portion (14) is arranged in connection with a duct means (8) of a container blank (10) adapted to be filled with its contents through the duct means (8).