The present invention relates to a bag or pouch made from a pair of flat walls formed by flexible sheet material and sealingly interconnected so as to define between the opposite walls a storage chamber for containing a fluid and at least one fluid discharge passage communicating with the storage chamber.

DE-A-26 47 399, DE-A-40 07 128, and DE-B-12 07 856 disclose bags or pouches the type similar to that described above. In these known bags, however, the opposite flexible wall parts defining the discharge passage therebetween are located between the opposite wall parts defining the storage chamber so that the pressure of a fluid contained within the storage chamber tends to press the opposite wall parts of the dis- charge passage into mutual sealing engagement. When a gaseous or liquid product contained in these bag-like containers is to be discharged a thin tube or a similar elongated object has to be inserted through the discharge passage in order to open the same.

Norwegian patent No. 96,943, British patent No. 1.463,579, and US patent No. 3,149,772 disclose a bag or pouch of the above type defining a storage chamber and a discharge passage arranged outside the storage chamber. A bag or pouch of this type having a discharge passage with improved sealing charac- teristics is disclosed in applicants' co-pending interna¬ tional patent application PCT/DK94/00135.

The present invention relates to a bag or pouch of the above type in which the self-sealing effect of the discharge pas¬ sage may be further improved. Thus, the discharge passage may be reliably sealed even when the discharge passage is rela¬ tively broad and also when the product contained in the storage chamber is a gas,-a_ gas mixture, or a low viscosity liquid having a small surface tension. The bag or pouch

according to the invention may be made self-sealing even when it is only partly filled with fluid.

When used in the present application the term "discharge passage" should be interpreted as a passage extending between 5 an innermost self-sealing passage part usually sealing the storage container and a passage outlet opening communicating with the ambient atmosphere. This means that fluid cannot flow from the storage chamber into the discharge opening unless the bag or pouch is exposed to a positive discharge 10 operation.

US patent No. 3,149,772 discloses a bag of the above type and proposes "artificial kinks" without disclosing how such kinks which "will usually not be recessary" can be made.

The present invention provides a bag or pouch of the above 15 type, which is characterized in that material of at least one of opposite parts of the walls defining the discharge passage or other parts of the bag closely adjacent to the discharge passage is arranged and/or has been modified at one or more positions mutually spaced along the length of the fluid -—--20 discharge passage so as to cause said opposite wall parts to tend to move into mutual sealing contact transversely to the discharge passage at or adjacent to each of said positions when the discharge passage upstream thereof is distended by fluid contained in the bag or pouch.

25 At least one of the opposite wall parts of the bag or pouch may have been modified by exposing the material of at least one of the opposite parts of the flat walls to a treatment so as to modify at least one characteristic thereof, and/or by choosing flexible sheet materials having different character-

30 istics for forming the opposite wall parts, and/or by locally reducing the bending resistance of at least one opposite wall parts defined by opposite sealing areas interconnecting the walls of flexible sheet material.

Such modification may take place before, during or after producing the bag or pouch. The flexible sheet materials being chosen to form the opposite wall parts could be of different types, for example different elasticity, stiffness, deformability etc., different thickness, and/or different laminates. The stiffness or bending resistance of the sealing areas could be locally reduced or increased by locally reducing or increasing the transverse extension of the sealed areas. The resistance can also be reduced by using a heat sealing pattern causing such local reduction of the bending resistance or by cutting notches or openings in the sealed areas.

The wall part or wall parts may be arranged or modified in any suitable manner causing the opposite wall parts to move into sealing contact as explained above. As an example, the wall material of the wall part or the opposite wall parts πϊay have been locally modified by heating, cooling, radiation, exposure to one or more chemical substances, and/or shrink¬ ing. As an example, the wall material to be heated or cooled may be brought into contact with or positioned adjacent to a heating or cooling element. Alternatively, the characteris¬ tics of the wall material may be modified by electromagnetic radiation of any suitable wave length or radioactive radi¬ ation. As another possibility, the wall material may be exposed to one or more chemical gaseous or liquid substances, which are able to modify the properties or characteristics of the material. As an example, the wall material may be caused to shrink under the influence of for example heat, radiation and/or chemical substances.

According to another embodiment, the wall material has been locally modified by mechanical treatment, such as rolling, vibrating, hammering and/or stretching, whereby a similar sealing effect of the discharge passage may be obtained.

While the sheet material being modified may be material located between the interconnecting seals defining the dis-

charge passage, the wall material or sheet material may alternatively or additionally be modified at least at one of the interconnecting seals defining the discharge passage so as to generate in at least one of the opposite wall parts defining the discharge passage stresses transversely to the passage. The material of the interconnecting seals may be modified by any of the means mentioned above. Stretching of the sheet material may, for example, be obtained by pinching or compressing the sheet material between a tool surface made from a hard material and a backing surface of a resilient material.

According to a further embodiment a pair of first and second folds extending transversely to and across the discharge passage may be formed in at least one of the opposite wall parts defining the discharge passage so as to define at the respective side of the discharge passage a pocket opening into the discharge passage at said first fold. When the discharge passage upstream of the first fold is distended by liquid such liquid penetrates into the pocket and tends to distend the same so as to move the opposite wall parts of the discharge passage into sealing contact between the first and second folds. The first fold is preferably arranged upstream of the second fold in the discharge passage, whereby liquid flowing out through the discharge passage may flow into the pocket opening and distend the pocket.

The discharge passage may be defined between a pair of inter¬ connecting seals having any angled and/or curved shape, and the transverse distance between the interconnecting seals may vary along the length of the discharge passage. Preferably, however, the discharge passage is defined between a pair of mutually spaced, co-extending sealing seams, which may, for example, be substantially parallel.

The bag or pouch according to the invention may have one, two or even more discharge passages. The discharge passage may, however, comprise branch passages. This means that a single

discharge passage may have two or more branch inlets and a single outlet. The branch passages may also be interconnected so as to define an annular passage which may then be con¬ nected to one ore more inlets and one or more outlets.

The opposite wall parts defining the discharge passage need not be of the same material and/or have the same thickness. Thus, the opposite wall parts may be made from different kinds of plastic material or may be a plastic film and a metal foil, respectively. Furthermore, the thicknesses of the wall parts may be different.

According to a further embodiment at least one of the oppo¬ site wall parts defining the discharge passage has been modified so as to obtain a curved or angled cross-sectional shape along a plane extending longitudinally to the discharge passage and transversely to the opposite wall parts defining the same. Such shape may, for example, be obtained by heat sealing the opposite wall parts by means of heat sealing members having the desired shape. When the discharge passage has such a curved or angled shape, the discharge passage may be opened by straightening it.

The discharge passage may communicate with the storage cham¬ ber at a junction position and may be arranged outside the storage chamber, and at least at one side of and adjacent to the fluid discharge passage the storage chamber may then extend beyond the junction position in a direction towards an outlet end of the discharge passage.

When such a bag or pouch is distended by an inner fluid pressure the opposite wall parts adjacent to the junction position defines (in a cross-sectional view) an outer angle (β in Fig. 31) with the central plane of the bag in its flat, empty, collapsed condition. It has been found that the self- sealing effect of the discharge passage of the bag or pouch is increased when the said angle is reduced. It has also been found that the angle β is reduced and that the self-sealing

effect of the bag or pouch is consequently increased when the storage chamber extends beyond the junction position in a direction towards an outlet of the discharge passage at least at one side and preferably at both sides of the fluid dis- charge passage.

At least one restriction may be defined in the discharge passage, for example at or closely adjacent to a sealing position. It has been found that also such restriction cau¬ sing a substantial local reduction of the width of the dis- charge passage may increase the s-elf-sealing effect of the bag or pouch. The restriction may have an unessential or a very small extension in the axial direction of the discharge passage, or it may extend along a substantial part of the length of the discharge passage. The discharge passage may be defined between a pair of spaced substantially parallel or non-parallel opposite heat sealed seams or other sheet inter¬ connecting seams, and the restriction may be defined by a projection extending transversely from one of the seams or by such projections extending against each other from the oppo- site seams.

The part of the storage chamber being adjacent to the dis¬ charge passage may be funnel-shaped which means that this part of the storage chamber is defined by a pair of sealing lines converging in the direction of the junction position. Al ernatively, the part of the storage chamber being adjacent to the junction point may be defined by sealing lines extend¬ ing substantially at right angles to the axis of the dis¬ charge passage as disclosed in the above Norwegian patent No. 96,943. However, the storage chamber may at least at one side and preferably at both sides of the fluid discharge passage and adjacent to the junction position be defined by a sealing line defining with the longitudinal axis of the discharge passage an angle which is smaller than 90°.

As mentioned above, the storage chamber may adjacent to the junction position be defined by sealing lines converging

towards the junction position so as to define a funnel-like shape opening into the discharge passage. In such case, the said restriction is preferably positioned substantially at the intersection of the extensions of the converging sealing lines.

The storage chamber may comprise a main chamber and an outlet chamber or metering chamber which are interconnected by a connecting passage, and the discharge passage may then com¬ municate with the outlet chamber or metering chamber at a position substantially opposite to the connecting passage. When such a bag or pouch is arranged such that the discharge passage is directed downwardly, a liquid fluid contained in the bag or pouch will flow from the main chamber into the metering chamber or outlet chamber through the connecting passage so as to refill the metering chamber when a liquid product has been dispensed from the metering chamber by manual operation of the discharge passage or by means of a suitable dispenser, e.g. as that disclosed in applicants' co- pending Danish patent application No. 0244/94.

The storage chamber defined in the bag or pouch according to the invention may comprise two or more aligned chamber sec¬ tions, and adjacent chamber sections may be interconnected by a communication passage. The bag or pouch may then have a segmented, hose-like shape. This embodiment is especially advantageous when the bag or pouch is used to contain air or another gas. Such an air-filled bag may, e.g., be used as a shock-absorber when packing fragile objects. Also other embodiments of the bag according to the invention may be used for such purpose.-

The bag or pouch according to the invention may be used for containing any kinds of gaseous or liquid products, such as air, gaseous and liquid disinfectants, alcohol and other liquid solvents, soaps, shampoos, creams, and other liquid cosmetics, drinks, ketchup, mustard and other liquid food- stuffs. Furthermore, the bag may be used as an infusion bag

for containing liquids to be introduced into a human or animal body. It is possible to discharge a product contained in the bag or pouch according to the invention by manipulat¬ ing the discharge passage and the adjacent part of the stor- age chamber. This may be done manually or by means of a special dispenser as mentioned above. In any case it is desirable to have the bag or pouch filled with the product arranged such that the fluid discharge passage depends freely. Therefore, the bag or pouch preferably comprises means for suspending the bag or pouch such that the fluid discharge passage and at least the adjacent part of the storage chamber may depend freely from the suspension means. Such suspension means may, e.g., comprise a pair of through openings defined in the opposite walls at opposite sides of the connecting passage. The bag or pouch may then be sus¬ pended from a pair of supporting pins or hooks extending through the openings, and the mutual distance between such supporting pins may be smaller than the distance between the through openings of the pouch whereby it may be ensured that liquid fluid may flow freely from the main chamber into the metering chamber via the connecting passage.

In addition to the fluid discharge passage the bag or pouch may comprise at least one further self-sealing passage exten¬ ding between the storage chamber and the ambient atmosphere and being defined between the opposite walls of the pouch.

One fluid may then be introduced into the storage chamber via said further self-sealing passage while another fluid is discharged through the discharge passage. As an example, a surgical instrument may be contained in the storage chamber and air may be evacuated from the storage chamber while a gaseous disinfectant, which may be less poisonous than ethylene oxide, is introduced into the storage chamber via the other self-sealing passage. A bag or pouch having only one discharge passage may also be used for packing surgical instruments under aseptic -conditions.

Similarly, when the bag or pouch is used for containing an infusion liquid the discharge passage may be connected to a cannula inserted into the patient, and metered amounts of a medicament may at the same time currently be fed into the storage chamber via said further self-sealing passage.

The opposite walls of the bag or pouch may be made from identical sheet material, such as a plastic film being of the same thickness. The opposite walls may, however, also be made from different sheet materials and/or be of different thicknesses. As an example, the opposite walls may be made from polyethylene films having a thickness of 50-250μ or other plastic films having a similar stiffness. One of or both of the opposite walls may be formed by a plastic film consisting of two or more layers of different plastic materials which have been co-extruded or laminated.

According to the invention the bag or pouch may comprise a restriction defined in the discharge passage at a position having a distance from the outlet end of the discharge pas¬ sage being less than half the axial length of the discharge passage. This restriction may be the only restriction of the discharge passage or may be in addition to a restriction formed in the inlet end portion of the discharge passage at the sealing position. The restriction formed in the outlet end portion of the discharge passage tends to counteract undesired dripping of liquid product from the free outer end portion of the discharge passage when a product discharge operation has been terminated.

Usually, it is desired that the width of the discharge pas¬ sage should be almost as large as possible in order to faci- litate product discharge from the bag or pouch. However, at the same time a reliable self-sealing effect of the discharge passage should be ensured. The largest possible width of the discharge passage is dependent on various parameters, such as surface tension, adhesion characteristics, and viscosity characteristics of the fluid, the material from which the

opposite flexible walls of the pouch are made, the stiffness and surface characteristics of such walls, and the shape or contour of the discharge passage and of the adjacent part of the storage chamber, etc. The width of the discharge passage may vary along the length of the passage. However, in most cases the minimum width of the discharge passage, such as the width of the passage at a restriction, is between 2 and 100 mm, preferably between 3 and 30 mm dependent i.a. on the above parameters.

In order to ensure good self-sealing of the discharge passage the axial length thereof is preferably at least one and preferably at least 1& times the minimum width of the dis¬ charge passage and more preferably about two times such minimum width. In order to efficiently prevent any leakage from a bag or pouch filled with a fluid product, the dis¬ charge passage may have a closed outlet end adapted to be cut by the user of the product so as to open the discharge pas¬ sage. As described in more detail below bags or pouches according to the present invention may have storage chambers and discharge passages defined therein with a great number of symmetrical or non-symmetrical shapes. In the preferred embodiment, however, the bag or pouch and the contours of the storage chamber and the discharge passage are substantially symmetrical about the longitudinal axis of the discharge passage.

As explained above, the discharge passage may be shaped in many different ways with various kinds of restrictions and with a width varying substantially along the length of the passage. Preferably, however, the fluid discharge passage defines a substantially rectilinear flow path extending from the junction position to the outlet opening of the discharge passage. This means that it is possible to insert a product filling or a product discharge tube into the discharge pas¬ sage so that such tube extends from the outlet opening of the passage through the axial length of the discharge passage and

into the storage chamber, whereby it is possible to fill and/or empty the bag or pouch via such tube.

The interconnecting seals defining the discharge passage may comprise a pair of longitudinally coextending, mutually transversely spaced seals arranged on at least one side and preferably on both sides of the discharge passage or closely adjacent thereto. This means that the interconnecting seal on at least one and preferably on both sides of the discharge passage is divided by at least one longitudinal area where the opposite wall parts are not sealed together, but define a hollow space therebetween. It has been found that this faci¬ litates transverse bending or shaping of the opposite wall parts defining the discharge passage as explained above.

Furthermore, the mutual sealing contact between the opposite wall parts of the bag or pouch may be obtained or further improved when the transverse dimension of the sealing interconnection defining the discharge passage and/or the adjacent part of the storage chamber has been reduced locally at opposite positions. Such local reduction may, for example, be obtained by including a suitably shaped, non-sealed area in the sealing interconnection, such as a heat sealing seam.

The invention also relates to a method of producing a bag or pouch, said method comprising arranging a pair of flat walls formed by flexible sheet material in opposite abutting rela- tionship and sealingly interconnecting said wall parts so as to define therebetween a storage chamber for containing a fluid and a fluid discharge passage communicating with the storage chamber, said method being characterized in arranging and/or modifying material of at least one of the opposite wall parts defining the discharge passage or other parts of the bag closely adjacent to the discharge passage at one or more positions mutually spaced along the length of the fluid discharge passage so as tα- _^ cause said opposite wall parts to tend to move into mutual sealing contact transversely to the discharge passage at or adjacent to each of said positions

when the discharge passage upstream thereof is distended by fluid contained in the bag or pouch.

As explained above the opposite wall parts defining the discharge passage may be formed into a curved or angled shape. Thus, transversely opposite parts of the interconnec¬ ting seals, which define the discharge passage, may be com¬ pressed between opposite complementary tool surfaces so as to deform said opposite parts. The opposite complementary tool surfaces may be made from a relatively stiff material. In the preferred embodiment, however, one of the opposite tool surfaces is made from a resilient material, such as rubber or a resilient plastic material. When the opposite tool surfaces are pressed together, the surface defined by the resilient material automatically adapts itself to the shape of the other tool surface, while the opposite parts of the intercon¬ necting seal compressed therebetween are deformed so as to create a self-sealing effect across the adjacent part of the discharge passage. At least one of the opposite tool surfaces may be heated, and the opposite complementary tool surfaces may be part of a heat sealing device, so that the operation described above may be performed simultaneously with heat sealing of the flexible walls of sheet material from which the bag or pouch is made.

The invention will now be further described with reference to the drawings, wherein

Fig. 1 is a plan view of a first embodiment of the pouch or bag according to the invention shown in its empty and flat condition,

Figs. 2-28 show the discharge passage and the adjacent part of the storage chamber of a variety of different embodiments of the bag or pouch according to the invention, Figs. 29 and 30 are plan views showing two further embodi¬ ments of the bag or pouch according to the invention in which the storage chambers are divided into interconnected chamber sections,

Fig. 31 is a diagrammatic sectional view showing a bag or pouch in a filled, distended condition,

Fig. 32 is a plan view of a further embodiment of the pouch or bag according to the invention shown in its empty and flat conditions, and

Figs. 33-47 shown the discharge passage defining parts of a further variety of different embodiments of the bag or pouch according to the invention.

The drawings illustrate bags or pouches each made from a pair of oppositely arranged flexible side walls, such as plastic films, which may be monoextrudates, coextrudates, and/or laminates. The opposite flexible side walls of the bag or pouch may be formed by the opposite side walls of a collapsed hose or tube section, which is heat sealed or otherwise sealingly interconnected at its opposite ends (Fig. 1) .

Alternatively, the bag or pouch may be made from a pair of separate, superposed flexible films or sheets, which have been heat sealed or otherwise sealingly interconnected along the contour of the pouch. In the drawings such heat sealed or otherwise sealingly interconnected areas have been cross- hatched.

The pouch shown in Fig. 1 has an upper marginal heat sealed area 10 having formed therein an upper suspension opening 11 positioned on a central symmetry axis 12 of the pouch. A pair of lower oppositely arranged heat sealed areas 13 are shaped so as to divide the inner space of the pouch into an upper main chamber 14 and a lower, smaller metering chamber or outlet chamber 15. The chambers 14 and 15 are interconnected by an interconnecting passage 16, and the outlet chamber 15 communicates with--at—downwardly directed discharge passage or spout 17. A pair of lower suspension openings 18 are formed in the lower heat sealed areas 13 and are positioned immedi¬ ately above the outlet chamber 15 on either side of the symmetry axis 13. The discharge passage 17 has a restriction 24 close to the outlet end thereof. This restriction is formed by a pair of oppositely directed extensions 19 of the

heat sealed areas 13. When a gaseous or liquid fluid has been filled into the main chamber 14 and the outlet chamber 15 of the bag or pouch shown in Fig. 1 so that the opposite flex¬ ible walls are distended by the inner fluid pressure, the discharge passage 17 is effectively sealed due to the shape of the discharge passage 17 and the adjacent part of the outlet chamber 15 as explained in more detail below.

The bag or pouch shown in Fig. 1 is adapted to be used in a dispenser of the type disclosed in applicants' co-pending Danish patent application No. 0244/94. The oppositely directed extensions 19 in the lower part of the discharge passage 17 tend to prevent undesired dripping of product from the discharge passage, when an amount of liquid product has been discharged from the pouch via the discharge passage or spout 17.

Figs. 2-28 diagrammatically illustrate a variety of possible alternative shapes of the discharge passage or spout 17 and of an adjacent storage chamber part 20 which may be a chamber corresponding to the outlet chamber 15 in Fig. 1 communica- ting with a main chamber 14, or may be a single storage chamber.

Fig. 2 illustrates a bag or pouch having a straight discharge passage 17 defined between a pair of substantially parallel sealing lines. The discharge passage 17 communicates with the storage chamber 20 at a junction position 21. As shown in Fig. 2, the storage chamber 20 extends beyond that junction position 21 in the direction of the outlet end 22 of the discharge passage. Thus, adjacent to the discharge passage 17 the storage chamber 20 is defined by a pair of sealing lines 23 each defining together with the axis 12 an angle α which is an acute angle, whereby the self-sealing effect of the discharge passage is substantially improved.

The embodiments shown in Fig. 3-6 substantially correspond to the embodiment shown in Fig. 2 with the exception that in

Figs. 3-6 the discharge passage 17 has been provided with restrictions 24. Thus, in Fig. 3 the discharge passage 17 has a restriction defined by oppositely directed extensions 19 of the heat sealed areas. In the embodiment shown in Fig. 4 the discharge passage 17 has three restrictions, each of which is defined by one extension 19, only. Fig. 5 shows an embodiment in which the discharge passage 17 has a single restriction extending along a substantial axial length of the passage 17 at the junction position 21, and in Fig. 6 a restriction 24 is formed at the junction position as well as adjacent to the outlet end 22 of the discharge passage 17.

In the embodiments shown in Figs. 7-12 the discharge passage 17 is at least partly defined by converging and/or diverging opposite sealing lines so that the width of the discharge passage varies continuously at least along part of the axial length of the discharge passage. The discharge passage 17 of the embodiment shown in Fig. 7 has restrictions 24 defined at the junction position 21 and adjacent to the outlet end 22 of the passage 17. In the embodiment shown in Fig. 8 restric- tions 24 are defined by means of extensions 19 at the junc¬ tion position 21 and adjacent to the outlet end 22 of the passage 17. Furthermore, a restriction 24 is defined at the middle of the discharge passage 17.

In the embodiment of Fig. 9 two restrictions 24 are formed in the discharge passage 17 by means of extensions 19 of the heat sealed area. In the embodiment shown in Fig. 10 only one restriction 24 is defined at the middle of the discharge passage 17, and in Figs. 11 and 12 restrictions 24 are defined at the junction position 21 and at the outlet end 22 of the discharge passage 17, respectively. In Fig. 12 the discharge passage 17 is partly defined by opposite, curved sealing lines, and in Fig. 13 the discharge passage 17 is stepped so that two restrictions 24 are formed by the second and third step, respectively.

The embodiment shown in Fig. 14 defines a discharge passage 17 having a restriction 24 defined at the junction position 21 by a pair of opposite extensions 19 of the sealing area, and these extensions also define bottom sealing lines of the storage chamber 20. A restriction 24 is also defined at the outlet end 22 of the discharge passage 17.

Fig. 15 illustrates an embodiment in which the part of the storage chamber 20 adjacent to the junction position 21 is defined by converging sealing lines, and a restriction 24 is defined by extensions 19 in the discharge passage 17 at a position adjacent to the intersection point of the extensions of such sealing lines.

In the embodiment shown in Fig. 16 the discharge passage 17 is shaped like a chamber having a square outline. The chamber or passage inlet and outlet define restrictions 24. The embodiment shown in Fig. 17 is similar to that shown in Fig. 2 with the exception that in Fig. 17 the storage chamber 20 is defined by opposite side seams converging in the direction of the discharge passage 17.

Figs. 18-21 show embodiments in which the inner end of the discharge passage 17 is defined by heat sealing lines cros¬ sing a heat sealing line defining the storage chamber 20, whereby storage chamber pockets 27 are defined on both sides of the inlet end of the discharge passage 17. In Figs. 18 and 19 the discharge passage 17 has substantially the same width along the length thereof while the discharge passage 17 is funnel shaped in the embodiment shown in Fig. 20. In Fig. 21 the storage chamber 20 is funnel-shaped.

The embodiment shown in Fig. 22 is similar to that shown in Fig. 15. However, the extensions 19 are differently shaped and positioned.

The embodiment shown in Fig. 23 is similar to the embodiments shown in Figs. 18-20. However, in Fig. 23 the discharge

passage 17 is positioned completely inside the sealing line 26 defining the adjacent part of the storage chamber 20. In the embodiment shown in Fig. 24 the discharge passage 17 also extends inwardly beyond the storage chamber sealing line 26, and the inner end of the discharge passage is defined by relatively large heat sealed areas 28 which may be relatively stiff. Such relatively stiff areas at the inlet end of the discharge passage 17 may further improve the self-sealing effect of the discharge passage.

The embodiment shown in Figs. 25 and 26 are similar to the embodiments shown in Figs. 15 and 22, the difference being that in Figs. 25 and 26 the opposite sealing lines of the storage chamber 20 are curved and that the restriction 24 is positioned adjacent to the outlet end 22 of the discharge passage 17.

Fig. 27 shows an embodiment in which the outlet passage is funnel-shaped, and a restriction 24 is defined at the outlet end 22 of the discharge passage. This restriction is formed by opposite heat sealed areas 29 at the outlet end of the passage. The embodiment shown in Fig. 28 corresponds to those shown in Figs. 15, 21, and 22 with the exception that in Fig. 28 the restriction 24 is defined at the outlet end 22 of the discharge passage 17.

Figs. 29 and 30 show embodiments in which the storage chamber has been divided into chamber sections 30 by pairs of oppo¬ site, transversely extending heat sealed areas 31 forming connecting passages 32 therebetween. When a pressure is applied to the outer walls of a chamber segment 30 fluid contained therein may escape into adjacent chamber segments via the connecting passages. Such fluid flow between the chamber segments 30 may be restricted more or less by proper¬ ly choosing the width of the connecting passages 32. Fluid flow between adjacent chamber segments 30 may be further restricted by shaping the heat sealed areas 31 as shown in Fig. 30. The connecting passages 32 may be considered a fluid

discharge passage where the angle α. (vide Figs. 2 and 3) defined between the border lines of the adjacent chamber segment 30 and the longitudinal axis of the pouch is acute, as will be described in more detail below.

In the embodiments of the bags or pouches illustrated in

Figs. 1-30 the self-sealing characteristics of the discharge passage have been further improved by stress zones 35 exten¬ ding transversely to the discharge passage 17. These stress zones have been provided by locally modifying the material in at least one of the opposite flexible side wall parts defi¬ ning the discharge passage by heating, cooling, radiation, exposure to chemical substances, shrinking or mechanical treatment, such as rolling, vibration, hammering or stretch¬ ing.

In Figs. 1-30 the stress zones 35 have been indicated by means of horizontally extending hatching lines. As indicated in Figs. 1-30, stress zones 35 may be provided in each bag or pouch at or adjacent to the junction position 21, one or more restrictions 24, and/or the outlet end 22 of the discharge passage 17. While in some of the embodiments shown in Figs. 1-30 two or more stress zones 35 have been provided in the discharge passage 17, it should be understood that some of these stress zones may be dispensed with.

As shown in Figs. 29 and 30, similar transverse stress zones 36 may also be formed at or adjacent to the heat sealed areas 31.

Fig. 31 diagrammatically shows a central section taken at right angles to the opposite walls of a bag or pouch of the type described above. Fig. 31 shows the discharge passage or spout 17 and the adjacent part of the bag or pouch when distended by an inner fluid pressure so that outer shoulders 33 are formed adjacent to the discharge passage or spout 17. These shoulders define an angle β together with a line 24 extending at right angles to the central symmetry axis 12 of

the bag or pouch. As mentioned above, it has been found that the angle β indicates whether the pouch or bag has good self- sealing characteristics or not. Thus, the self-sealing effect is increased when the angle β is diminished.

EXAMPLE 1

A test was made to demonstrate the interrelationship between the self-sealing effect of the discharge passage 17 and the angle a (shown in Figs. 2 and 3) and the angle β (shown in Fig. 31) . A bag of the type shown in Fig. 1 was used where the outlet passage 17 and the adjacent part of the outlet chamber 15 had a shape substantially as shown in Fig. 3, but without any stress zones 35. The opposite walls of the bag or pouch were made from a laminate of two outer layers, each being a 45μ polyethylene film and an inner core layer of a 12μ polyester film. The width w of the main chamber 15 was 40 mm, the width d of the discharge passage 17 was 10 mm, and the axial length 1 of the discharge passage was 20 mm. Tests were made for different values of the angle cn ranging from 10° to 180°, and the corresponding values of the angle β were measured in a plane extending through the axis 12 and at right angles to the pouch walls (at right angles to the plane of the drawing in Fig. 1) . When measuring the value of the angle β the bag or pouch was filled with pure tap water, and the inner water pressure was gradually increased to a value at which the fluid discharge passage 17 was just about to open, and the value of the angle β was measured at that inner pressure.

The following results were obtained: a β

180 80

170 75

160 75 not self-sealing

150 65

140 60

130 65

120 40

110 35 accidentally

100 25 self-sealing

90 20

80 20 very good self-

70 15 sealing characte¬

60 10 ristics

50 5

40 20

30 20 extremely good self

20 30 sealing characteris

10 45 tics

The above test results show that the self-sealing characte¬ ristics of a pouch as that shown in Fig. 1 may be substan¬ tially improved by reducing the angle o..

EXAMPLE 2

Bags or pouches of the type shown in Fig. 1, but without any stress zones 35 were made. The walls of the bags were made from a flexible foil or film of polyethylene having a thick¬ ness of 50-80μ and from a coextrudate of polyethyle, ethylene vinyl alcohol and polyethylene with a total thickness of 50- 80μ, respectively. The angle a was 60-80°, the width d of the discharge passage 17 was 3-5 mm, and the length 1 of the dis¬ charge passage was 10-12 mm. The bag showed good self-sealing characteristics with contents of water, soap water, alcohol and air.

EXAMPLE 3

A bag or pouch of the type shown in Fig. 1 was made from a laminate of 90μ polyethylene and 12μ polyester. However, the discharge passage 17 of the bag did not have any stress zones 35. The angle α. was 70° and the width d of the discharge passage 17 was 8 mm and the length 1 of the discharge passage was 16 mm. The bag was used for containing liquid soap and shampoo and showed very good self-sealing characteristics. In order to prevent undesired dripping of the product subsequent to a discharge process, extensions 19 of the type shown in Fig. 1 were positioned about 5 mm from the outlet end 22 of the discharge passage.

The bag or pouch shown in Fig. 32 defines a storage chamber 14 communicating with the ambient atmosphere via a discharge passage or spout 17 which is defined between opposite, sub¬ stantially parallel heat sealing lines. The self-sealing characteristics of the discharge passage 17 has been improved by a transversely extending sealing zone 35 having been provided by locally modifying the material of one or more of the opposite flexible wall parts in any of the manners described above.

Fig. 33 illustrates a discharge passage 17 having an inter¬ mediate annular part 37. One or more self-sealing zones or stress zones 35 may have been provided at any location of the discharge passage including the annular part 37 as indicated by radially extending lines.

Figs. 34 and 35 illustrate two further different embodiments each shown in plan view and sectional view, respectively. In the embodiment shown in Fig. 34 the outlets out of the bag or pouch have an offset or stepped-like cross-sectional shape so as to provide a pair of transverse bends 38. This shape may be obtained by heat sealing the opposite walls of sheet material along the opposite heat sealing seams 39 between a pair of complementary heating surfaces of a similar shape.

The embodiment shown in Fig. 35 may be produced in a similar manner. In this case, however, the bag or pouch part defining the discharge passage 17 has a curved cross-sectional shape.

The bends 38 of the embodiment shown in Fig. 34 and the curvature of the embodiment shown in Fig. 35 provides an excellent self-sealing effect to the discharge passage 17. However, when desired the discharge passage may be opened by straightening the same. Such straightening may be performed manually or in a suitable dispensing device.

Figs. 36-44 show embodiments, in which transverse self-seal¬ ing zones or stress zones have been provided across the discharge passage 17 by locally heating opposite parts of the heat sealing seams 39. In Fig. 36, heat has been supplied to opposite pairs of substantially rectangular areas 40 of the heat sealing seams 39 so as to generate stress zones or heat sealing zones 35 between each pair of such areas 40. The areas 40 may be heated after or simultaneously with heat sealing of the opposite walls along the seams 39. In both cases the areas 40 are heated to a higher temperature than that used for heat sealing the areas or seams 39.

The embodiments shown in Fig. 37 corresponds to that shown in Fig. 36 with the exception that in Fig. 37 the discharge passage 17 has a restriction defined between a pair of oppositely directed extensions 19 which also provide a self- sealing effect at that location as described above.

In the embodiments shown in Figs. 38-41 the areas 40 being locally heated are defined by wave-like lines. Heating of the wave-like areas 40 causes the discharge passage or spout to attain a wave-like cross-sectional shape as shown in Fig. 40, whereby an extraordinary self-sealing effect may be obtained. In the embodiment shown in Fig. 38 the discharge passage 17 has a restriction defined between the oppositely directed extensions 19.

In the embodiments shown in Figs. 42-44 the heated areas 40 are narrow zones extending transversely across each of the heat sealing seams or areas 39. As shown in the cross-sec¬ tional view the heated zones 40 define transversely extending narrow grooves. Such grooves may have been obtained by pinch¬ ing the areas or seams 39 between a projecting heated edge and an opposite backing surface of a resilient material. In Fig. 42 one of the heated areas 40 is aligned with the exten¬ sions 19 while in Figs. 43 and 44 the heated areas 40 are arranged adjacent to and spaced from the extensions 19, respectively. It should be understood that in the embodiments shown in Fig. 42 a pair of extensions 19 may also be arranged in alignment with one or more of the other heated areas, and that any of these extensions 19 may be formed by transverse flow of the sheet material when the grooves or heated areas 40 are being formed.

Figs. 45 and 46 illustrate a further embodiment of the dis¬ charge spout or passage 17 in plan view and cross-sectional view, respectively. The discharge passage 17 is defined between a pair of oppositely arranged walls 41 and 42 of sheet material. The wall 42 has a double fold 43 so as to define an upwardly open pocket 44. When a pressure is applied to the fluid contained in the storage chamber 14 of the bag or pouch so that the fluid is pressed into the discharge passage 17, such fluid becomes trapped in the pocket 44. The fluid pressure tends to expand the pocket 44 in a transverse direction so as to press the adjacent opposite wall parts of the discharge passage 17 into sealing engagement, whereby a self-sealing effect is obtained.

Fig. 47 shows an-embodiment in which each heat sealing area defining the discharge passage 17 and the adjacent part of the pouch comprises at least two mutually transversely spaced, co-extending heat sealing seams 45 and 46 so as to define a channel 47 between the adjacent seams 45 and 46. The channel 47 may have a pair of oppositely directed branched parts 48. A self-sealing zone 35 extending transversely

across the discharge passage 17 has been provided in a manner described above. It has been found that the presence of the channel 47 increases the self-sealing effect obtained in the area 35. Furthermore, it has been found that a similar stress area 35 is obtained between the opposite ends of the branched channel parts 48.

It should be understood that various alterations, combina¬ tions and changes may be made within the scope of the present invention.