Flexible bags – With closure – Self-closing type
Patent
1987-12-16
1989-04-18
Marcus, Stephen
Flexible bags
With closure
Self-closing type
B65D 3024
Patent
active
048221805
DESCRIPTION:
BRIEF SUMMARY
The invention relates to a foil bag, primarily for keeping a liquid, consisting of two welded-together foils with an inlet extending from the edge of the bag to its inside along a channel defined by the weld seams.
Bags of this type are used for keeping liquids, pastes and similar pumpable media, whether these be articles of food, technical products or the like.
Filling of the bag takes place by pouring liquid through an inlet channel, whereafter the channel is closed either by tying up the bag or by welding it together or by applying an adhesive tape around the inlet.
The bag with contents can, if so required, then be frozen and the bag later be emptied either by being torn open or by thawing it and letting out the liquid contents through the channel.
The disadvantage of these known bags is that they can only be closed by means of some subsequent shutting off of the inlet. This requires additional foil material or other auxiliary equipment, and moreover a considerable handling in order to close the bag in a completely liquid-proof manner.
It is the object of this invention to overcome these drawbacks of the known bags, and this is achieved in that the foils are folded towards the inside of the bag for the formation of two valve flaps in the channel, said valve flaps being welded together with the welding seams defining the channel for the formation of two pockets being open towards the inside of the bag and extending in all essentials in the entire length of the channel.
Hereby is achieved a self-closing valve, in that once the bag is filled, liquid will be pressed out between each valve flap and foil wall in the channel, which will distend the pockets. Hereby the two valve flaps will be pressed against each other for liquid-proof closing of the channel with no need for additional closing means or handling. Since the pockets are relatively big the surface of contact and hence the tightness degree will be very considerable so that a good and constant closing of the bag is achieved by means of these valve flaps which make up an integrated part of the bag.
Hereby the operating and handling of the bag is made easier, and the bag can be produced by machine in single pieces or in endless rolls. This makes the bag suitable for a disposable packing bag, because the manufacturing costs and material consumption can be kept relatively low.
When the liquid is to be let out from a filled bag, this may for instance be effected by inserting a pipe between the valve flaps, whereafter the liquid can move freely out through the pipe. The pipe can then be removed from the channel, and the bag will be closed when liquid is once again supplied to the pockets and distends these for tightening abutment against one another. This can normally be done by turning the bag upside down.
If the contents of the bag is frozen, the bag can be torn open in a usual manner and the contents be removed. Prior to being frozen, such a bag will thus be completely tightly closed in order that handling and storing in the freezer prior to the freezing can take place with no liquid leakage at all.
Moreover, the bag can be produced in such a manner that there is no air between the foil layers in order that the adding of liquid to the bag can take place without first evacuating the bag of air. This means that the cross section of the channel need not be particularly large which increases the degree of tightness of the valve flaps which do not cover each other over such a large area.
By, as referred to in claim 2, narrowing the channel, an efficient closing is achieved since the distension of the foil around the pockets during filling will cause tensions in the foil around the narrowing and thus increase the pressure on the valve flaps so that these are kept close together.
By, as referred to in claim 3, designing the narrowing with two pointed ends pointing towards each other, these tensions may be concentrated in an area near the centre of the channel and thereby the highest degree of tightness is obtained in just this area.
Finally it is expedient, a
REFERENCES:
patent: 2800269 (1957-07-01), Smith
patent: 2804257 (1957-08-01), Hasler et al.
patent: 3189252 (1965-06-01), Miller
patent: 3263903 (1966-08-01), Waller et al.
patent: 3806025 (1974-04-01), Marshall
Gjelstrup Lars
Hansen Flemming
Lindknud Plast A/S
Marcus Stephen
Stucker Nova
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