Abstract:
A plastic spout which is adapted to be sealed between two foil walls of a pouch. The spout has a spout body, which forms a passage for delivering a medium from the pouch and/or feeding a medium to the pouch. In a bottom part thereof, the spout, on opposite sides, forms a sealing zone for a sealed connection to an adjoining foil wall. The sealing zones of the spout body are formed by sealing walls which project downward from the spout body. The sealing walls can preferably move flexibly transversely with respect to their plane and, on their inner side, are unsupported or are supported by one or more flexible supporting parts of the spout body.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS  
       [0001]     This application is a divisional application of U.S. patent application Ser. No. 10/492,474 filed on Apr. 12, 2004, which is the national stage filing under 35 U.S.C. §371 of PCT/NL02/00646, filed Oct. 10, 2002, which claims priority to NL 1019161, filed Oct. 11, 2001, which is incorporated herein by reference. 
     
    
     FIELD OF THE INVENTION  
       [0002]     The present invention relates to a plastic spout which is intended to be sealed between two foil walls of a pouch, comprising a spout body which forms a passage for delivering a medium from the pouch and/or feeding a medium to the pouch, which spout body, on opposite sides, forms a sealing zone for sealed connection to the adjoining foil wall.  
         [0003]     The present invention also relates to a method for sealing a plastic spout between two foil layers of a pouch.  
       BACKGROUND OF THE INVENTION  
       [0004]     WO 00/66448, in particular  FIGS. 9   a - d , in the name of the present applicant has disclosed a plastic spout, which is adapted to be sealed between two foil walls of a pouch. The known spout has a spout body with a central tubular part which forms a passage for delivering a medium from the pouch and/or feeding a medium to the pouch, the medium being, for example, a liquid, powder or gas.  
         [0005]     The known spout body, on opposite sides thereof, forms a sealing zone for the adjoining foil wall. These sealing zones are formed by ribs, which project outwards from the central tubular part, lie at an axial distance from one another and adjoin bridge parts, which lie diametrically with respect to the tubular part. The ends of the bridge parts end in thin lips. As seen in the plane running transversely with respect to the tubular part of the spout body, the ribs, together with the adjoining bridge parts and the lips, form a boat-shaped contour on their outer circumference.  
         [0006]     During the sealing, the known spout body is introduced between the foil walls of a pouch and a fused join is brought about between the sealing zones of the spout, which are formed by the outermost surfaces of the ribs, the bridge pieces and the lips, on the one hand, and the adjoining parts of the foil walls of the pouch, on the other hand.  
         [0007]     The known spout body does not always prove satisfactory, in particular with regard to the sealed connection between the foil walls and the spout body. For example, one drawback is that producing the sealed connection requires undesirably large amounts of heat and time, with the result that the production rate is undesirably low. In practice, this sealing time is shortened by greatly increasing the pressure with which the foil walls are pressed onto the sealing zones, but this leads to a poor-quality sealed connection.  
         [0008]     Another drawback of this known spout is that with certain types of foil, for example foil with a layer of aluminium, the ribs in the sealing zones may cause damage to the foil.  
         [0009]     JP2001-240083 has disclosed a spout, the spout being provided on the underside with downward projecting thin sealing walls, which between them delimit a substantially oval space. When this known spout is being sealed between the foil walls of a pouch, the spout is first of all placed onto a support member which fits into the oval space. During the sealing, heated sealing jaws are placed onto the outer side of the foil walls, so that the sealing walls and adjoining foil walls, which are clamped between the support member and the sealing jaws, fuse and a welded joint is formed. The support member holds the sealing walls in the intended shape in this arrangement. The sealing walls are designed to be thin, making it possible to produce the sealed connection more quickly.  
         [0010]     One drawback of the spout described in JP2001-240083 is that the support member requires the pouch to be open on the underside, so that the support member can project outwards. Furthermore, positioning the spout on the support member and removing the pouch from the support member after sealing has taken place takes up time, which once again slows the production process.  
       OBJECTS OF THE INVENTION  
       [0011]     It is an object of the present invention, according to a first aspect thereof, to provide a spout which can be sealed in place without using the support member. It is a further object to provide a method to seal a plastic spout between two foil walls of a pouch.  
       SUMMARY OF THE INVENTION  
       [0012]     For this purpose the first aspect of the invention provides a spout, which is characterised in that the sealing walls each have a curvature over their entire length, such that each sealing wall is outwardly convex over its entire length with respect to an imaginary plane passing through the outermost ends, which adjoin one another, of the sealing walls.  
         [0013]     This design of the sealing walls means that the sealing walls are stable if, during the sealing operation, external pressure is applied to the sealing walls by means of pressure-exerting means, such as heated sealing jaws. Even with a low thickness of the sealing walls (less than 2 millimetres), this stability is such that there is no need to use a support member during the sealing operation, with the result that the support member is preferably omitted.  
         [0014]     When the spout is being sealed in place, only a small amount of heat is required to melt the sealing walls on the side of the foil walls which have been pressed onto them. This is because the heat which is supplied during sealing cannot be dissipated to parts of the spout which lie further away from the surface which is to be melted.  
         [0015]     The heat required to form a seal can be provided using all known sealing methods, for example using heated sealing jaws and/or with the aid of ultrasound.  
         [0016]     Further advantages of the spout with sealing walls according to the first aspect of the invention relate to the production of the spout in a suitable injection mould. This mould can be of relatively simple design, and furthermore the sealing walls require little plastic material. It is also possible for the cooling time for the sealing walls in the mould to be short, which is advantageous with regard to the production rate and cost price. Moreover, on account of the sealing walls, the mould can be provided with simple and efficient cooling means. In particular, the mould part which defines the inner side of the sealing walls and is composed of one or more components can be designed with a relatively large volume of material, so that there is space for efficient cooling means therein.  
         [0017]     It is preferable for the sealing walls to be designed to be thin. The wall thickness of the sealing walls is in practice preferably at most 2 millimetres. The invention provides the possibility for the sealing walls to be designed with a thickness which as a minimum corresponds to the thickness of the foil walls.  
         [0018]     It is preferable for the spout to be designed in such a manner that the sealing walls can move flexibly transversely with respect to their plane and on their inner side to be unsupported or supported by one or more flexible supporting parts of the spout body. Then, after the spout has been fitted in the pouch, these sealing walls have a shock-absorbing capacity and can yield elastically with foil walls of the pouch. This reduces the risk of damage to and possible leaks from the pouch at the location of the transition from the foil wall to a sealing wall. Furthermore, the flexibility of the sealing walls is advantageous for the production of the sealed connection, for example because broader dimensional tolerances of the spout body are acceptable without having an adverse effect on correct operation of the sealing device.  
         [0019]     In a preferred embodiment, it is provided that the outer sides of the sealing walls, against which the foil walls come to bear, are of smooth design, i.e. without ribs or the like. This design is advantageous, for example, if the foil wall includes one or more layers of metal foil, in particular aluminium foil.  
         [0020]     It is preferable for the spout body to comprise a transverse wall which extends transversely between the sealing walls, the passage extending through the transverse wall. The transverse wall is preferably situated at or close to the upper edge of the sealing walls. For example, an outwardly projecting tubular part of the spout body, which forms the passage, adjoins the transverse wall.  
         [0021]     The first aspect of the invention also relates to the sealing of a plastic spout between foil walls, in particular of a pouch. In this aspect, use is made of pressure-exerting means which press the foil walls onto the sealing walls of the pouch without a support member internally supporting the sealing walls. In an advantageous embodiment, during the sealing of the spout use is made of pressure-exerting means which yield elastically to press the foil walls onto the sealing walls of the spout. By way of example, use is made of pressure-exerting jaws with an elastic layer, for example made from heat-resistant foam material.  
         [0022]     In an advantageous embodiment, the spout or just the sealing walls is/are preheated before the spout is sealed into the pouch.  
         [0023]     A second aspect of the invention relates to a spout in which the sealing walls are connected via flexible connecting bodies to a tubular part which fits between the sealing walls.  
         [0024]     A third aspect of the invention provides a spout which is characterised in that the transverse wall is provided with one or more corrugations transversely with respect to the plane of the transverse wall, which impart flexibility to the transverse wall, in such a manner that the transverse wall allows the flexible movement of the sealing walls. The result of this measure is that the transverse wall does not cancel out the intended flexibility of the sealing walls, so that the shock-absorbing capacity and the sealing properties are positively influenced compared to a transverse wall which is of rigid design.  
         [0025]     The present invention also relates to a pouch provided with a spout according to the invention.  
         [0026]     Further advantageous embodiments of the spout according to the various aspects of the invention are described in the claims and the following description with reference to the drawing. The drawing is on a significantly enlarged scale compared to reality. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0027]      FIG. 1   a  shows a side view of a first exemplary embodiment of the plastic spout according to the first aspect of the invention,  
         [0028]      FIG. 1   b  shows a front view of the spout shown in  FIG. 1   a,    
         [0029]      FIG. 1   c  shows a view from below of the spout shown in  FIG. 1   a,    
         [0030]      FIG. 1   d  shows a perspective view of the spout shown in  FIG. 1   a  from above,  
         [0031]      FIG. 1   e  shows a perspective view of the spout shown in  FIG. 1   a  from below,  
         [0032]      FIG. 2   a  shows a side view of a second exemplary embodiment of the plastic spout according to the first aspect of the invention,  
         [0033]      FIG. 2   b  shows a front view of the spout shown in  FIG. 2   a,    
         [0034]      FIG. 2   c  shows a view from below of the spout shown in  FIG. 2   a,    
         [0035]      FIG. 2   d  shows a perspective view of the spout shown in  FIG. 2   a  from above,  
         [0036]      FIG. 2   e  shows a perspective view of the spout shown in  FIG. 2   a  from below,  
         [0037]      FIG. 3   a  shows a side view of an exemplary embodiment of the plastic spout according to the second aspect of the invention,  
         [0038]      FIG. 3   b  shows a front view of the spout shown in  FIG. 3   a,    
         [0039]      FIG. 3   c  shows a view from below of the spout shown in  FIG. 3   a,    
         [0040]      FIG. 3   d  shows a perspective view of the spout shown in  FIG. 3   a  from above,  
         [0041]      FIG. 3   e  shows a perspective view of the spout shown in  FIG. 3   a  from below,  
         [0042]      FIG. 4   a  shows a side view of an exemplary embodiment of the plastic spout according to the third aspect of the invention,  
         [0043]      FIG. 4   b  shows a front view of the spout shown in  FIG. 4   a,    
         [0044]      FIG. 4   c  shows a view from below of the spout shown in  FIG. 4   a,    
         [0045]      FIG. 4   d  shows a perspective view of the spout shown in  FIG. 4   a  from above,  
         [0046]      FIG. 4   e  shows a perspective view of the spout shown in  FIG. 4   a  from below. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0047]      FIGS. 1   a - e  show a spout  150  which is produced by injection-moulding from a suitable plastic material and which is intended to be sealed between two foil walls of a pouch.  
         [0048]     The spout  150  has a single-part spout body with, on the top side, an outwardly projecting tubular part  152  which forms a passage  153  for delivering a medium from the pouch and/or feeding a medium to the pouch.  
         [0049]     The tubular part  152  is provided with a screw thread  154  for a screw cap (not shown), which can be used to close off the spout  150 .  
         [0050]     The outwardly projecting tubular part  152  is furthermore provided with a locking flange  155  for the screw cap and, beneath this, two circumferential flanges  156  which are used for handling means for the spout  150  and the pouch to engage on after the spout  150  has been sealed in the pouch.  
         [0051]     On the underside, the spout  150  is provided with two sealing walls  158 ,  159  which project freely downwards, adjoin one another at their diametrically opposite ends and have an oval contour both on the inner side and on the outer side. The sealing walls  158 ,  159  adjoin the remainder of the spout body  150  only at their upper edge. Therefore, the sealing walls  158 ,  159  between them delimit an oval space.  
         [0052]     In particular, the sealing walls  158 ,  159  have a curvature over their entire length, in such a manner that each sealing wall  158 ,  159  is externally convex with respect to the imaginary line passing through the outermost ends, which adjoin one another, of the sealing walls. This is more stable than the design which is known from the prior art in which the sealing walls have straight wall parts, and certainly more stable than the design according to the prior art in which the sealing walls have parts with an inwardly directed convexity.  
         [0053]     The latter variants provide too little resistance to the sealing walls being undesirably folded inwards, for example while the sealed connection is being produced.  
         [0054]     The sealing walls  158 ,  159  are designed to be smooth on the outer side. The sealed connection to the foil walls can then be produced over virtually the entire surface of the thin sealing walls  158 ,  159 . In this context, the thin design of the sealing walls  158 ,  159  makes a significant contribution to the short sealing time, since little heat has to be supplied in order to produce the fused connection.  
         [0055]     The sealing walls  158 ,  159  have no internal support and are flexibly movable and can easily be moved transversely with respect to the plane of the sealing walls  158 ,  159 .  
         [0056]     The flexibility of the sealing walls  158 ,  159  provides the pouch with a shock-absorbing capacity, as can be seen from a test which involves dropping a filled pouch. Furthermore, the flexibility of the sealing walls  158 ,  159  avoids overloading the foil walls of the pouch in the vicinity of the bottom edge of the sealing walls  158 ,  159 .  
         [0057]     When the sealed connection is being produced, it is preferable to use jaws which completely surround the sealing walls, so that a sufficient pressure can then be obtained between the foil walls and the sealing walls.  
         [0058]     In a variant, to produce the sealed connection sealing jaws which are provided with ribs or another profile, for example a waffle profile or a block profile, are used instead of sealing jaws with smooth jaw surfaces, so that the initial pressure is exerted at the location of the elevated parts of the profile.  
         [0059]     In the spout  170  shown in  FIG. 2   a - e , the sealing walls  171 ,  172  are designed with an even greater curvature than in the embodiment shown in  FIG. 1 .  
         [0060]     At the location where the sealing walls  171 ,  172  meet, outwardly projecting thin lips  173 ,  174  are formed, these lips forming the transition to the parts of the foil walls of the pouch which are sealed together.  
         [0061]     The inner side of the sealing walls may be of smooth design, as shown in the drawings, but it would also be possible to provide one or more formation, for example a thickened edge or a groove, in order to secure another component in the space between the sealing walls. By way of example, in this way it is possible for a flexible insert to be clipped into place, reducing the size of the effective area of the passage.  
         [0062]     The spout  90  according to the second aspect of the invention will now be explained in more detail with reference to  FIGS. 3   a - e.    
         [0063]     The spout  90  has a single-part spout body with, at the top side, an outwardly projecting tubular part  92  which forms a passage  93  for delivering a medium from the pouch and/or feeding a medium to the pouch.  
         [0064]     The tubular part  92  is provided with a screw thread  94  for a screw cap (not shown), which is used to close off the spout  90 .  
         [0065]     The outwardly projecting tubular part  92  is furthermore provided with two circumferential flanges  95 , which are used for handling means for the spout  90  and the pouch to engage on after the spout  90  has been sealed into the pouch.  
         [0066]     On the underside, the spout  90  is provided with two sealing walls  98 ,  99  which project freely downwards and have an eye-shaped contour both on the inner side and on the outer side. Since the sealing walls  98 ,  99  have straight parts in the vicinity of their ends, these sealing walls do not comply with the first aspect of the invention.  
         [0067]     On the underside, the spout body  90  comprises a tubular part  100  which extends in line with the tubular part  92  and the diameter of which is smaller than the corresponding dimensions of the space delimited by the sealing walls  98 ,  99 .  
         [0068]     The tubular part  100  is connected to the inner side of the sealing walls  98 ,  99  via two diametrically opposite flexible connecting bodies  101 ,  102 .  
         [0069]     In this case, the connecting bodies  101 ,  102  are provided with a curvature and are therefore flexible, so that the connecting bodies  101  allow the flexible movement of the sealing walls  98 ,  99 .  
         [0070]     The spout  110  according to the third aspect of the invention will now be explained in more detail with reference to  FIGS. 4   a - e.    
         [0071]     The spout  110  has a single-part spout body with, at the top side, an outwardly projecting tubular part  112  which forms a passage  113  for delivering a medium from the pouch and/or feeding a medium to the pouch.  
         [0072]     The tubular part  112  is provided with a screw thread  114  for a screw cap (not shown), which is used to close off the spout  110 .  
         [0073]     The outwardly projecting tubular part  112  is furthermore provided with two circumferential flanges  115 , which are used for handling means for the spout  110  and the pouch to engage on after the spout  110  has been sealed into the pouch.  
         [0074]     On the underside, the spout  110  is provided with sealing walls  118 ,  119  which project freely downwards and have an eye-shaped contour both on the inner side and on the outer side.  
         [0075]     On the underside, the spout body  110  comprises a tubular part  120  which extends in line with the tubular part  112  and the diameter of which is smaller than the internal dimensions of the space delimited by the sealing walls  118 ,  119 .  
         [0076]     A transverse wall  122 , which is provided with corrugations, extends between the sealing walls  118 ,  119 , so that the transverse wall is flexible and allows the flexible movement of the sealing walls  118 ,  119 .  
         [0077]     The transverse wall  122  also forms a flexible connection between the tubular parts  112 ,  120 , which lie in line with one another, on the one hand, and the sealing walls  118 ,  119 , on the other hand.  
         [0078]     The design of the spout shown in  FIG. 4  is highly advantageous with regard to the shock-absorbing capacity of the pouch. The pressure which is formed in the medium in the pouch in a test which involves dropping the pouch, in particular where the medium is a liquid, will now lead to elastic deformation of the transverse wall  122  (and also of the sealing walls), so that there is no pressure surge leading to (a seam of) the pouch giving way.  
         [0079]     It will be clear that the spout body may have all kinds of designs, for example may be designed in combination with a stopper for closing off the passage, a male element if the spout is used as a connector, etc.