METHOD FOR SEALING A FLEXIBLE PACKAGE OF COLLAPSIBLE TYPE

Abstract

In accordance with the present inventive concept, there is provided a method for sealing a flexible package of collapsible type. The method comprises providing a first seal extending transverse a filling channel of the flexible package and providing a second seal extending transverse a filling channel of the flexible package. Said second seal overlaps said first seal such that a combined seal is provided comprising a top portion formed solely by a first sealing unit, an intermediate portion formed by the first and a second sealing unit, and a bottom portion formed solely by the second sealing unit. The method further comprises setting operating parameters comprising a time parameter, a temperature parameter and a pressure parameter for providing said first seal and for providing said second seal such that a sealing characteristic below a threshold value is obtained in said top portion and said bottom portion and such that a sealing characteristic equal to or above the threshold value is obtained in said intermediate portion.

Claims

1. A method for sealing a flexible package of collapsible type comprising providing a first seal extending transverse a filling channel of the flexible package, and providing a second seal extending transverse the filling channel of the flexible package, said second seal overlapping said first seal such that a combined seal is provided comprising a top portion formed solely by a first sealing unit, an intermediate portion formed by the first and a second sealing unit, and a bottom portion formed solely by the second sealing unit, characterized by setting operating parameters comprising a time parameter, a temperature parameter and a pressure parameter for providing said first seal and for providing said second seal such that a sealing characteristic below a threshold value is obtained in said top portion and said bottom portion and such that a sealing characteristic equal to or above the threshold value is obtained in said intermediate portion.

2. The method according to claim 1, further comprising transferring said flexible package from said first sealing unit to said second sealing unit.

3. The method according to claim 1, wherein said first seal and said second seal are provided intermittently.

4. The method according to claim 1, wherein said first seal is provided with a width in the range of 1 to 5 millimeters.

5. The method according to claim 1, wherein said second seal is provided with a width in the range of 1 to 5 millimeters.

6. The method according to claim 1, wherein said first and second seals are provided such that the intermediate portion has a width in the range of 1 to 5 millimeters.

7. The method according to claim 1, wherein said first and second seals are provided extending in parallel.

8. The method according to claim 1, wherein said first and/or second seal is provided by a sealing unit comprising a permanently heated sealing jaw.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0039] The above, as well as additional objects, features and advantages of the present invention will be better understood through the following illustrative and non-limiting detailed description of preferred embodiments of the present invention, with reference to the appended drawings, where the same reference numerals will be used for similar elements, wherein:

[0040] FIG. 1 is a schematic side view of a production line comprising an embodiment of a device for sealing a flexible package according the present inventive concept.

[0041] FIG. 2 is a perspective view of the production line in FIG. 1.

[0042] FIG. 3 is a schematic view of the permanently heated sealing jaw and the abutment jaw comprised in the first and the second sealing units in FIG. 1 and FIG. 2.

[0043] FIG. 4 is a schematic side view of the first and the second sealing unit comprised in the device in FIGS. 1 and 2.

[0044] FIG. 5a is a schematic front view of a flexible package wherein a seal has been provided in accordance with an embodiment of the inventive concept.

[0045] FIG. 5b is a schematic front view of another flexible package wherein a seal has been provided in accordance with another embodiment of the inventive concept.

[0046] FIG. 6 is a flow chart illustrating a method for sealing a flexible package according to an embodiment of the present inventive concept.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

[0047] Next, the inventive concept will be described with reference to FIGS. 1 and 2 which illustrate a schematic side view and a schematic perspective view, respectively, of a production line 100 for filling and sealing a plurality of flexible packages 200 of collapsible type. As will be detailed below, the production line 100 comprises an embodiment of a device for sealing a flexible package according the present inventive concept. The production line 100 may be referred to as a filling machine.

[0048] In the following, the wording package 200 and wording flexible package 200 will be used interchangably.

[0049] The plurality of flexible packages 200 may be provided from a material web according to methods well-known to a person skilled in the art. According to the present embodiment, the packages 200 are provided to the production line 100 in the form of a continuous web of packages (not shown). The web of packages are rolled up to be supplied in roll form to the production line 100.

[0050] The rolls are arranged to be unwound and fed to the production line 100. Initially, the packages 200 may be fed edgewise and subsequently the packages 200 may be fed intermittently broadwise.

[0051] The production line 100 comprises a filling unit 110, a first sealing unit 120, a second sealing unit 130 and a gas-filling unit 140. The first sealing unit 120 and the second sealing unit 130 are comprised in an embodiment of the inventive device for sealing the flexible package 200. The packages 200 are handled at each of these units in consecutive order in a direction as indicated by the arrow X in FIGS. 1 and 2. The units 110, 120, 130, 140 are arranged along a horizontal direction which is a longitudinal direction of the production line 100. Moreover, according to the present embodiment the units 110, 120, 130, 140 are arranged essentially equidistantly from each other.

[0052] There is also provided a transfer unit for transferring the flexible packages 200 between the units 110, 120, 130, 140. In particular, the transfer unit is arranged to transfer the packages 200 from the first sealing unit 120 to the second sealing unit 130. For clarity, the transfer unit has been left out from FIGS. 1 and 2. According to one example, the transfer unit is arranged to transfer the flexible packages 200 between the units 110, 120, 130, 140 by means of an essentially semi-circular movement, whereby the flexible packages 200 arrive at each unit 110, 120, 130, 140 by means of an substantially vertical motion. According to another example, the transfer unit is arranged to transfer the flexible packages 200 between the units 110, 120, 130, 140 by means of an essentially horizontal movement, whereby the flexible packages 200 arrive at each unit 110, 120, 130, 140 by means of an substantially horizontal motion.

[0053] In FIGS. 1 and 2, two pairs of flexible packages 200 are displayed, but it is understood that there may be more packages 200 in the production line 100 simultaneously. In particular, there may be a pair of flexible packages 200 at the filling unit 110 and a pair of flexible packages 200 at the gas-filling unit 140, while the pairs of flexible packages 200 are being located at the sealing units 120 and 130.

[0054] It is noted that for clarity only a part of the production line 100 is shown in FIG. 1 and FIG. 2. Clearly, there may be another similar part of the production line (not shown) for providing filling and sealing of the other package 200 of the pair of flexible packages. In fact, there may be a plurality of production lines for providing filling and sealing of a plurality of flexible packages 200. By way of example, each production line may be arranged to fill and seal a pair of flexible packages. The plurality of production lines may be provided in parallel.

[0055] In the following, a single package 200 will be described, but it is clear that any number of packages 200 may be treated similarly.

[0056] The filling unit 110 is arranged to fill the flexible package 200 with a liquid product. In a filling operation, a filling channel of the package 200 is opened by means of a suction cup, thereby forming an opening. The opening of the flexible package 200 is defined by two opposite side walls of the package. A filling nozzle (not shown) is then guided through a hole 112 formed between a first and a second gripping means into the filling channel via the opening of the flexible package 200. More specifically, each gripping means comprises two prongs and, during the filling operation, the prongs on the first and the second gripping means are arranged to exert pressure on each other whereby the hole 112 is formed. The package 200 is filled when it assumes an upright position. The filling nozzle is introduced into the filling channel by means of a relative vertical displacement between the filling nozzle and the package 200.

[0057] Before inserting the filling nozzle into the filling chamber of the package 200, a top seal of the package 200 is arranged to be removed in order to access the filling channel of the package 200. By way of example, this operation may be performed at a separate removal unit comprised in the production line 100. Additionally, there is a separation unit (not shown) located before the filling unit 110 for separating the packages 200 from each other, i.e. wherein the web of packages 200 which provided on the roll are separated. In a non-limiting example, the edgewise feed referred to above may comprise the act of removing a top seal in order to open the filling channel of the package 200 as well as the act of separating the packages 200.

[0058] In FIG. 1 and FIG. 2, the flexible packages 200 are shown in a filled state and an unfilled state, respectively. However, with respect to FIG. 2 it is realized that once the flexible packages 200 have passed the filling unit 110, they have been filled with the liquid product as in FIG. 1, whereby the flexible packages 200 assume an expanded state wherein the side walls of each of the packages 200 are separated.

[0059] The first sealing unit 120 is arranged to provide a first seal to the flexible package 200. The first sealing unit 120 comprises a first abutment jaw 122 and a first permanently heated sealing jaw 124. Additionally, the first sealing unit 120 comprises a first protection cover 125 for keeping the flexible package 200 separated from the first permanently heated sealing jaw 124.

[0060] Similarly, the second sealing unit 130 is arranged to provide a second seal to the flexible package 200. The second sealing unit 130 comprises a second abutment jaw 132 and a second permanently heated sealing jaw 134. Additionally, the second sealing unit 130 comprises a second protection cover 135 for keeping the flexible package 200 separated from the second permanently heated sealing jaw 134.

[0061] According to present embodiment, the first 120 and the second 130 sealing unit comprises the same components. FIG. 3 is a schematic view of the first 122 and the second 132 abutment jaw and the first 124 and the second 134 permanently heated sealing jaw which are comprised in the first 120 and the second 130 sealing units in FIGS. 1 and 2. It is understood that the abutment jaws 122, 132 and the permanently heated sealing jaws 124, 134 have an extension in a transverse direction, i.e. in a direction normal to the cross-sectional planar surface displayed in FIG. 3. In FIG. 2 it may be seen that, according to the present embodiment, a width of the abutment jaws 122, 132 as well as a width of the permanently heated sealing jaws 124, 134 substantially correspond to a width of an upper portion of the package 200.

[0062] Clearly, according to an alternative embodiment, the first 120 and the second 130 sealing unit may comprise different components. For example, the abutment jaws and/or the sealing jaws may be designed differently.

[0063] The first abutment jaw 122 comprises a first tapering engagement notch 126 and the second abutment jaw 132 comprises a second tapering engagement notch 136. The notch 126 and 136 determine a width of the first and the second seal, respectively. According to the present embodiment, the tapering engagement notches 126, 136 are formed by an elastic material.

[0064] In FIG. 4 there is illustrated a schematic side view of the first sealing unit 120 to the left and the second sealing unit 130 to the right. It is also illustrated how to provide a combined seal 300 of the flexible package 200 extending transverse the filling channel of the flexible package 200 at the upper portion thereof. The resulting combined seal 300 comprises a first seal 302 and a second seal 304.

[0065] Incidentally, note that the positions of the first 120 and second 130 sealing units in FIG. 4 have been interchanged as compared to FIGS. 1 and 2.

[0066] As shown in the enlargement 4a in FIG. 4, the first sealing unit 120 is arranged to provide the first seal 302 on the flexible package 200 by means of the first abutment jaw 122 and the first permanently heated sealing jaw 124. More specifically, in operation the first abutment jaw 122 is pressed towards the first permanently heated sealing jaw 124 whereby the first seal 302 is provided on an upper portion of the flexible package 200, which in operation is placed between the first abutment jaw 122 and the first permanently heated sealing jaw 124. A first portion of the material in the upper portion of the package 200 is melted by the action of the first abutment jaw 122 and the first permanently heated sealing jaw 124 for forming the first seal 302.

[0067] Moreover, in the enlargement 4b in FIG. 4 it is shown that the second sealing unit 130 is arranged to provide the second seal 304 on the flexible package 200 by means of the second abutment jaw 132 and the second permanently heated sealing jaw 134. Analogously to the first sealing unit 120, in operation the second abutment jaw 132 is pressed towards the second permanently heated sealing jaw 134 whereby the second seal 304 is provided on an upper portion of the flexible package 200, which in operation is placed between the second abutment jaw 132 and the second permanently heated sealing jaw 134. A second portion of the material in the upper portion of the package 200 is melted by the action of the second abutment jaw 132 and the second permanently heated sealing jaw 134 for forming the second seal 304. Part of the second portion overlaps with the first portion.

[0068] The second seal 304 is offset with respect to the first seal 302. More specifically, the second seal 304 is displaced in a longitudinal direction of the flexible package 200 with respect to the first seal 302. This offset is implemented by displacing the second sealing unit 130 by a distance D with respect to the first sealing unit 120 in a vertical direction as shown in FIG. 4.

[0069] Moreover, the offset is such that the first 302 and the second 304 seals are overlapping in a region of the upper portion of the package 200, thereby forming an intermediate portion 316. Hence, the combined seal 300 comprises three portions: a top portion 312 formed solely by the first sealing unit 120, a bottom portion 314 formed solely by the second sealing unit 130, and an intermediate portion 316 formed by the first sealing unit 120 as well as the second sealing unit 130.

[0070] Thereby, the intermediate portion 316 provides a stronger part of the combined seal 300 than the top portion 312 and the bottom portion 314. In particular, the intermediate portion 316 has been pressed and heated by the first 120 and second 130 sealing units during a longer time as compared to the top portion 312 and the bottom portion 314 which have been pressed solely by the first sealing unit 120 and the second sealing unit 130, respectively.

[0071] In FIG. 5a there is shown a schematic front view of a flexible package 200 in an upright position wherein a combined seal 300 has been provided on an upper portion of the flexible package 200 in accordance with an embodiment of the inventive concept. It is noted that the dimensions of the combined seal 300 have been exaggerated for illustrative purposes. According to this embodiment, the combined seal 300 extends across the entire package 200 in the transverse direction of the package. In particular, the combined seal 300 transverse a filling channel 210 of the package 200, thereby sealing the product within a compartment 202 of the package 200 which is defined by the broken lines in FIG. 5a. In particular, the intermediate portion 316 transverses the filling channel 210 of the package 200 for forming a sufficient seal. According to the embodiment in FIG. 5a, the filling channel 210 also operates as an opening portion of the package 200.

[0072] In FIG. 5b there is shown a schematic front view of a flexible package 200 in an upright position wherein a combined seal 300 has been provided on an upper portion of the flexible package 200 in accordance with another embodiment of the inventive concept. The tilted lines in FIG. 5b indicate a cross-sectional view of the package 200. It is understood that the combined seal 300 comprises a first 302 and a second 304 seal as explained above, and thereby a top portion 312, a bottom portion 314 and an intermediate portion 316. The combined seal 300 transverses the filling channel 210 of the package 200, thereby sealing the product within the compartment 202 of the package 200. In particular, the intermediate portion 316 transverses the filling channel 210 of the package 200 for forming a sufficient seal.

[0073] It is clear that FIG. 5b indicates an exemplary position of the combined seal 300 and that, according to alternative embodiments, the combined seal 300 may be located at different positions. For example, the combined seal 300 may be located closer to or farther away from the top of the package 200. Also, the combined seal 300 may be shifted to the left or the right in FIG. 5b. However, it is important that the combined seal 300 transverse the filling channel 210 within the package 200 for providing sufficient sealing of the package 200.

[0074] The flexible package 200 according to the embodiment in FIG. 5b further comprises a handle portion 220 which is formed by a gas-filled duct 222. Moreover, the package 200 comprises an opening portion 230 comprising a tab which may be torn apart for allowing a user to access the product from the package 200.

[0075] The gas-filling unit 140 is arranged to fill the package 200 with gas, such as air, in the duct 222 for forming the handle portion 220 of the package 200 in FIG. 5b. The gas-filling unit 140 comprises a nozzle (not shown) for introducing air into the duct 222. The gas-filling unit 140 is also arranged to seal the duct 222 at an upper portion thereof for containing the gas in the handle portion 220.

[0076] Next, a method for sealing the flexible package 200 will be described according to an embodiment of the present inventive concept with reference to the flow chart in FIG. 6. The method may be implemented in the production line 100 which in particular comprises the first sealing unit 120 and the second sealing unit 130 as has been described in the above. The flexible package 200 is provided to the production line 100 from a web of packages as has been described above.

[0077] First, the flexible package 200 is transferred by means of the transfer unit (not shown) to the filling unit 110. At the filling unit 110, the flexible package 200 is filled with a product, such as a liquid product (Box 410). More specifically, a top seal is first removed from the package 200 for accessing the filling channel 210 of the package 200. Thereafter, the filling channel 210 is opened by means of the suction cup, thereby forming an opening, and the filling nozzle is inserted into the filling channel 210 and the compartment 202 is filled with the product. The filling nozzle is subsequently removed from the filling channel 210.

[0078] Thereafter, the flexible package 200 is transferred by the transfer unit from the filling unit 110 to the first sealing unit 120 (Box 420). Once at the first sealing unit 120, the first seal 302 is provided on the package 200 (Box 430) according to the above. The first seal 302 is provided to the package 200 during a first sealing time t.sub.1.

[0079] The flexible package 200 is then transferred by the transfer unit from the first sealing unit 120 to the second sealing unit 130 (Box 440). At the second sealing unit 130, the second seal 304 is provided on the package 200 (Box 450) according to the above. The second seal 304 is provided to the package 200 during a second sealing time t.sub.2.

[0080] The total sealing time is given by the sum of the first and second sealing times, i.e. t=t.sub.1+t.sub.2. The total sealing time t is chosen to be longer than or equal to a critical sealing time t.sub.crit which is sufficiently long for obtaining a sufficient seal. Additionally, the applied pressure P to the package 200 between the abutment jaws 122, 132 and the permanently heated sealing jaws 124, 134 and temperature T of the permanently heated sealing jaws 124, 134 are chosen suitably for obtaining a sufficient seal. In other words, PP.sub.crit and TT.sub.Ct, where Pent and T.sub.crA is a critical pressure and a critical temperature, respectively.

[0081] Thus, operating parameters are set for providing the first and the second seals 302. 304. These operating parameters comprise a time parameter, a temperature parameter and a pressure parameter. The operating parameters for providing the first seal may be different from the operating parameters for providing the second seal.

[0082] The operating parameters are set such that a sealing characteristic below a threshold value is obtained in said top portion and in said bottom portion and such that a sealing characteristic equal to or above the threshold value is obtained in said intermediate portion.

[0083] The threshold value corresponds to the sealing characteristics of a seal having been exposed to a proper sealing process in order to form a sufficient or functional seal. The proper sealing process for a given material and material thickness is dependent on the operating parameters: time, temperature and pressure.

[0084] In accordance with the inventive concept, it is only the intermediate portion, formed by the first and second seals overlapping each other, that is exposed to a proper sealing process, i.e. that has a sealing characteristic equal to or above the threshold value.

[0085] Lastly, the package 200 is transferred away from the second sealing unit 130 (Box 460). Thereafter, the package 200 may be further processed. By way of example, the package 200 may be transferred to the gas-filling unit 140. At the gas-filling unit 140, the duct 222 may be gas-filled by a gas such as air, cf. the package in FIG. 5b. According to the embodiment in FIG. 5b, the gas-filled duct 222 forms a volume formed by two opposing side walls. By means of the gas-filled duct 222, the rigidity of the package 200 increases.

[0086] Moreover, after the package 200 has been provided with a gas-filled handle portion 220, it may be transferred to other units in the production line 100. For example, the package 200 may be transferred to a packing unit wherein the package 200 becomes packed in a box (not shown). Before being packed, the package 200 may be adjusted or aligned to a suitable position and orientation, by performing a rectilinear displacement of the package 200 and by rotating the package 200 around one or several axes.

[0087] According to an alternative embodiment, however, the package 200 is not provided with a duct 222 and there is no need for a gas-filling unit 140 in the production line 100. A non-limiting example of such a package 200 is provided in FIG. 5a.

[0088] It is understood that the method described above may be repeated for a plurality of packages 200. As described in the above, the packages 200 may be provided to a production line 100 in a row. Moreover, multiple packages 200 arranged side-by-side may be provided to the production line 100. For example, there may be a pair of packages 200 provided side-by-side as shown in FIG. 2. Additionally, it is clear that there may be a plurality of production lines 100 arranged side-by-side. In these cases, a separation unit (not shown) may be located before the filling unit 110 for separating the plurality of packages 200 from each other.

[0089] The invention has mainly been described above with reference to a few embodiments. However, as is readily appreciated by a person skilled in the art, other embodiments than the ones disclosed above are equally possible within the scope of the invention, as defined by the appended patent claims. For example, the particular order of the various units included in the production line 100 may be varied. In relation to this, the steps comprised in the method may also be varied. Additionally, the particular form of the sealing units described must be considered as non-limiting as there are other ways of designing the sealing units. For example, the shape and/or the material of the abutment jaw may be different. Also, according to alternative embodiments, the sealing jaw does not have to be permanently heated. For example, there may be a separate heating member arranged next to the sealing jaw and/or abutment jaw for providing an improved sealing by means of intermittent heating.