FR2716868A1 - Mfr. of flexible pocket for containing medicinal fluid - Google Patents

Abstract

The pocket (1) is formed from a section of extruded cylindrical tube (2). It includes at least one access tube (4) provided with an annular collar (5) fitted into the wall of the cylindrical tube section. The two longitudinal edges of the pocket are formed by two ends of the cylindrical tube, each sealed by a weld (3). The technique includes fitting an electrically conducting core inside the sleeve and applying two electrodes to this. A source of high frequency current is applied to the two electrodes in order to form the required welds. The pockets are then cut apart.

Description

 The invention relates to a sealed pocket made of flexible synthetic material, in particular a pocket for infusion liquid, as well as its manufacturing process.

 Such a pocket is a reservoir, the capacity of which can vary, depending on the model, from 100 ml to 5,000 ml. The material chosen to make this pocket has characteristics compatible with the liquid that the pocket is intended to contain. In the case of infusion bags, this liquid is a medicine intended to be injected into a patient.

 The flexible bag is generally equipped with two access tubes, which make it possible to introduce liquid into or out of the bag. A first access tube, intended for the outlet of the liquid, may comprise a membrane that can be perforated by a trocar connected to a tube, itself connected to a hypodermic needle. The second access pipe is most often separate from the first. It may include a latex patch which can be punctured by a syringe needle for transferring a medicament from the syringe to the bag.

The latex patch becomes tight again after the needle has been removed.

 The liquid can flow through the first access tube, by gravity for example. The pocket is often provided with an eyelet, so that it can be hung. This flow can be done without air coming to replace the flowed liquid, because unlike a rigid tank, the flexible bag can collapse as it empties and adapt its internal volume to that of the remaining liquid . This is an advantage of the flexible pouch compared to a glass bottle.

 Other advantages of the flexible pouch are its lightness as well as its good impact resistance.

 Generally, the flexible bags are made of flexible polyvinyl chloride (PVC), in the form of an extruded sheath. They are often produced according to the process described below.

 A sheath roll is cut into sections, the length of which is equal to the length of the pocket. This gives a sleeve open at both ends. One end is closed by a weld comprising a suspension eyelet. The other end receives two segments of pipe, in polyvinyl chloride for example, which are welded to the pocket during the welding closing the second end. Two operations are generally necessary: a first annular welding operation to weld the tubes to the pocket and a second flat welding operation to close the pocket and make it waterproof.

 This process has several drawbacks. First of all, it is difficult to perform an annular weld, and these welds are sometimes defective. Then, it is difficult to open the sheath, especially when it is made of polyvinyl chloride, to introduce the access pipes.

Finally, the asepsis of the pocket obtained is random since each pocket is open and an electrode is introduced into the access tube during the annular welding.

 To overcome some of these drawbacks, it is known to weld flat, on a flat film, for example polyvinyl chloride (PVC), pipes provided with a flange, then to fold the film and to weld it in the form of poached. Thus, it is no longer necessary to carry out annular welding, but, the film being open, it is exposed to bacteriological and particulate contamination and the bag is therefore not aseptic.

 The object of the present invention is to provide, on the one hand, a bag of waterproof flexible material having only flat welds and whose aseptic qualities are guaranteed and, on the other hand, a simple method of manufacturing a such pocket.

 To this end, the pocket which it offers is a waterproof pocket made of flexible synthetic material obtained from a section of extruded cylindrical sheath, comprising at least one access pipe, characterized in that each access pipe has a annular flange fixed on the wall of the sheath section, and in that the two longitudinal edges of the pocket are formed by the two section ends of the extruded sheath closed by welding.

 The fact that the access pipes are provided with an annular flange allows the pipes to be welded to the wall of the sheath section by carrying out a flat weld.

When this watertight pocket made of flexible synthetic material serves, for example, as an infusion pocket, then advantageously, it comprises two access pipes each provided with a flange welded to the external face of the wall of the sheath as well as a weld , situated at
The opposite of the access pipes and delimiting an area in which there is a perforation provided to allow the suspension of the bag.

In order to manufacture these bags aseptically, the invention also provides a method of manufacturing such bags from a continuous sheath. This process consists of
- engaging an electrically conductive core inside the sheath having at least one bearing surface for the area of the sheath which must receive at least one tubing,
- Position at least one access tube on the sheath, at a point in the sheath located on the bearing surface of the core, the collar of the tube being in contact with the sheath
place a first cylindrical tubular electrode on each access pipe to be welded and a second electrode facing the core, the surface of the second electrode facing the core being much greater than the area of the first electrode facing the core,
- passing in the two capacitors mounted in series, constituted for the first, by the first electrode and the core separated by the sheath and the flange, and for the second, by the second electrode and the core separated by the sheath, a current high frequency in order to weld the collar on the sheath,
- flatten the sheath fitted with access pipes,
- transversely weld the flattened sheath thus forming the longitudinal edges of the pockets,
- cut out, and possibly print, fill and plug the pockets obtained.

 The fact of mounting two capacitors in series, the metal core being a plate common to these two capacities, makes it possible to have a closed space in which the core is located and where no impurity can enter. It is therefore sufficient for the core to be sanitized before the start of manufacture.

 Furthermore, since the surface of the second electrode facing the core is much larger than the area of the first electrode facing the core, the temperature rise at the second capacitor is much smaller than at the first, and the welding temperature is therefore reached only on the side of the first electrode, thus making it possible to weld the collar on the sheath.

However, a more conventional thermal welding process can also be used, depending on the nature of the flexible material used. In this case, the method consists of
- thread the sheath on an electrically conductive core having at least one bearing surface for the area of the sheath which must receive at least one tubing,
- position an access tube on the sheath, at a point in the sheath located on the bearing surface of the core, the collar of the tube being in contact with the sheath,
- weld the collar on the sheath by thermal welding,
- flatten the sheath fitted with access pipes,
- transversely weld the flattened sheath thus forming the longitudinal edges of the pockets,
- cut out, and possibly print, fill and plug the pockets obtained.

 In both processes (high frequency or thermal welding), the core used is advantageously a block of polished stainless metal, of generally parallelepipedal shape, having two upstream and downstream ends, at least the upstream end being of prismatic shape, and such that 'once introduced into the sheath, it is supported vertically and guided by horizontal rollers, so that its upstream prismatic end is oriented downwards and that the sheath passes between the core and the rollers.

 Thus, the core is an electrical conductor, having planar lateral support faces. The prismatic shape allows the walls of the sheath to be separated to allow the core to be engaged in the sheath. The core being made of metal, is relatively heavy and its weight opposes the resistance of the sheath during the separation of its walls.

 Finally, to maintain the asepsis of the manufactured pockets, the part surrounding the core is placed under a source of ultraviolet.

 In any case, the invention will be clearly understood with the aid of the description which follows, with reference to the appended diagrammatic drawing representing, by way of nonlimiting example, a flexible bag according to the invention as well as its manufacturing process.

Figure 1 shows a section of sheath provided with access pipes
Figure 2 shows a flexible bag according to the invention;
Figure 3 shows a manufacturing line implementing a manufacturing method according to the invention;
Figure 4 is a simplified electrical diagram of the high frequency welding device shown in Figure 3.

 The flexible pouch, object of the invention, is designated by the reference 1, and has a rectangular shape. It is obtained from a sheath section (Figure 1) which forms its two lateral faces 2. The two ends of the sheath section are closed by welds 3 forming the longitudinal edges of the flexible bag 1. On one on the non-welded sides of the pocket are two access pipes 4. Each of these pipes 4 is provided with a flange 5 welded to the sheath, at the level of the fold separating the two side walls 2. On the other side not welded from the pocket, a weld 6 delimiting an area of the side walls 2 is produced. In this zone, there is a perforation 7, crossing the two walls 2. Thus, the pocket 1 can be suspended from a hook not shown.

 The flexible synthetic material used to make such a bag is preferably polyvinyl chloride (PVC).

 Figure 3 shows a flexible pouch manufacturing line like that described above.

 Such a pocket is made from a continuous sheath 10 of polyvinyl chloride (PVC) wound on a roller 11, located at the upstream end of the production line. The sheath is then guided so as to travel a vertical path from bottom to top, by one or more rollers 12 acting as a pulley.

 In the vertical passage, the walls of the flattened sheath 10 are first of all separated. To do this, a block of stainless metal 13 has been introduced through the end of the sheath and is trapped in the sheath.

This metal block 13 has a generally parallelepiped shape elongated vertically. The two upstream and downstream ends have a prismatic shape. The wedge shape thus obtained facilitates the separation of the walls of the sheath 10. This metal block 13 is preferably polished, so that the sheath slides better thereon.

 The sheath 10 is pulled upwards. It then tends to take the metal block 13 with it, because of friction, but especially also because of the force necessary to separate the walls of the sheath 10. The metal block 13 must then have sufficient mass, so that its weight can oppose these efforts. It is therefore preferably massive.

 The metal block 13 is supported and guided by horizontal rotating rollers.

Horizontal support rollers 14 are placed under the block
13 and the support at the faces of the lower prism. The axis of each roller 14 is substantially parallel to one of the faces of the prism.

 Guide rollers 15 parallel to the support rollers 14 hold the block 13 at the side faces of the parallelepiped.

 The sheath 10, the walls of which are peeled off, then passes between the block 13 and the rollers 14, 15. While it is already vertical, but its walls are not yet separated, the sheath 10 is situated in a vertical plane in which the lower sharp edge of the metal block 13 is located.

 Depending on the type of access pipe 4 to be welded to the pocket 1, perforations 16 can be made on the edge of the sheath 10 which is still flattened, at the places intended to receive access pipes 4.

 The access pipes 4 are welded to the sheath 10 in the following manner: a pipe 4 is inserted into a tubular electrode 18, of a shape adapted to the pipe 4. The electrode 18 / pipe 4 assembly is then positioned on the sheath 10, either on a perforation 16, or at the place where the tubing 4 must be welded, so that the flange 5 is in contact with the sheath 10. The flange 5 is on a flat side face of the metal block 13 , and is pressed against the latter by the electrode 18. The surface of this electrode facing the metal block is substantially equal to the surface of the flange 5 and has substantially the same shape as the latter. A second electrode 19 is placed opposite the face of the metal block 13 opposite the face on which the flange 5 is located. The surface of this second electrode 19 facing the metal block 13 is much larger than the surface of the flange 5, or of the first electrode 18.

 These two electrodes are connected to a high frequency generator 20 of 27.3 MHz. When the current flows, a temperature rise is caused at the level of the two capacitors which constitute the first electrode 18 isolated from the metal block by the sheath 10 and the flange 5 and the second electrode 19 isolated from the metal block 13 by the sheath 10 (Figure 4). The rise in temperature is proportional to the area of the capacitors. It is therefore much larger at the first electrode 18 than at the second 19.

The welding temperature is then reached at the flange 5 and a small temperature variation on the side of the second electrode 19.

 When the access pipes 4 are welded to the sheath 10, the latter can again be flattened. It suffices for this to pass the sheath 10 which is fitted with pipes 4 and which is no longer fitted on the metal block 13, on a roller 12 to modify the direction of the path of the sheath 10. After this roller 12, the sheath 10 is in a horizontal plane.

 The sheath then passes through several stations. Some of these positions are optional and the order of passage of the sheath at these positions can be changed.

 For example, the sheath can first pass through a printing station, where the designation of the product it is intended to contain, as well as other characteristics are printed on the walls of the pocket. Then it passes into a punching station, where the punching 7 for hanging the bag 1 is made. Then come the welding stations. The weld 6 sealing the pocket 1 around the perforation 7 is first produced. Then the welds 4 closing the longitudinal sides of the pocket 1 are made perpendicular to the axis of the sheath 10. The welds 6 and 4 are flat welds.

 Once all the welds have been made, the pocket itself is finished. It suffices to separate, in a cutting station, the pockets 1 from one another. These pockets 1 can be filled and closed before or after the cutting station.

 It goes without saying that the invention is not limited to the pocket described and to the manufacturing process described; on the contrary, it embraces all its variants.

 Thus, for example, the pocket may comprise one or more than two access tubes according to the use that it is desired to make of the pocket. Likewise, the perforation intended to allow the bag to be suspended, as well as the welding associated with it, are optional.

 If the pocket is made of a flexible material other than polyvinyl chloride (PVC), a welding process, other than that of high frequency can be used. In the case of a thermal welding process, only a heating electrode is necessary, and the welding is obtained when the flange is pressed against the sheath by the electrode, the metal core then serving as a counter-support.

Claims (6)

 1. Watertight flexible plastic bag obtained from a section of extruded cylindrical sheath, comprising at least one access tube (4), characterized in that each access tube (4) has an annular collar (5 ) fixed to the wall of the sheath section, and in that the two longitudinal edges of the pocket are formed by the two section ends of the extruded sheath closed by welding.  2. Bag according to claim 1, characterized in that it comprises two access pipes (4) each provided with a flange (5) welded to the outer face of the wall of the sheath as well as a weld (6 ), located opposite the access pipes (4) and delimiting an area in which there is a perforation (7) provided to allow the bag to be suspended.  3. A method of manufacturing a bag according to claim 1, from a continuous sheath, characterized in that it consists of  - engaging inside the sheath (10) an electrically conductive core (13) having at least one bearing surface for the area of the sheath to receive at least one tubing,  - Position at least one access tube (4) on the sheath (10), at one point of the sheath located on the bearing surface of the core (13), the flange (5) of the tube being in contact sheath  - place a first cylindrical tubular electrode (18) on each access pipe (4) to be welded and a second electrode (19) facing the core, the surface of the second electrode facing the core being much greater than the surface of the first electrode facing the core,  - pass through the two capacitors mounted in series, constituted for the first by the first electrode (18) and the core (13) separated by the sheath (10) and the flange (5), and for the second, by the second electrode (19) and the core (13) separated by the sheath (10), a high frequency current in order to weld the flange on the sheath,  - flatten the sheath (10) provided with access pipes (4),  - transversely weld the flattened sheath (10) thus forming the longitudinal edges of the pockets,  - cut out, and possibly print, fill and plug the pockets {1) obtained.  4. A method of manufacturing a bag according to claim 1, from a continuous sheath, characterized in that it consists of  - engaging inside the sheath (10) a core (13) having at least one bearing surface for the area of the sheath to receive at least one tubing,  - Position an access tube (4) on the sheath (10), at a point in the sheath located on the bearing surface of the core (13), the flange (5) of the tubing being in contact with the sheath,  - weld the collar (5) on the sheath (10) by thermal welding,  - flatten the sheath (10) provided with access pipes (4),  - transversely weld the flattened sheath thus forming the longitudinal edges of the pockets,  - cut out, and possibly print, fill and plug the pockets (1) obtained.  5. Method according to one of claims 3 or 4, characterized in that the core (13) is a block of polished stainless metal, of generally parallelepipedal shape, having two upstream and downstream ends, at least the upstream end being prismatic shape, and in that, once the core is introduced into the sheath (10), it is supported vertically and guided by horizontal rollers (14, 15), so that its upstream prismatic end is oriented towards the bottom and that the sheath (10) passes between the core (13) and the rollers (14, 15).  6. Method according to one of claims 3 to 5, characterized in that the part surrounding the core (13) is placed under a source of ultraviolet to maintain asepsis.