AU674028B2

AU674028B2 - Radiofrequency welding electrode for multicompartment plastic film bags intended for medical use, and bags produced with same

Info

Publication number: AU674028B2
Application number: AU51156/93A
Authority: AU
Inventors: Bernard Vallot
Original assignee: Stedim SA
Current assignee: Sartorius Stedim Biotech SA
Priority date: 1993-05-05
Filing date: 1993-10-04
Publication date: 1996-12-05
Anticipated expiration: 2013-10-04
Also published as: EP0696958A1; EP0696958B1; FR2704801A1; AU5115693A; CA2162039A1; DE69308898D1; JPH08509631A; FR2704801B1; WO1994025252A1

Description

I

OPI DATE 21/11/94 APPLN. ID 51156/93 III~II EH ADJP DATE 05/01/95 PCT NUMBER PCT/FR93/00973 AU9351 156

DEMAN,

(51) Classification internationale des brevets 5: (11) Numiro de publication internationale: WO 94/25252 B29C6510, A6J 1/0 Al(43) Date de publication internationale: 10 novembre 1994 (10.11.94) (21) Num&o de la demnande internationale: PCT/FR93/00973 (81) Etats disigu~s: AU, CA, JP, US, brevet europ~en (AT, BE, CH, DE, DK, ES, MR GB, GR, IE, IT, LU, MC, NL, PT, (22) Date de di6ft international: 4 octobre 1993 (04.10.93) SE).

Dona6es relatives A la priorWt: Publi6e 93/05737 5 mai 1993 (05.05.93) FR Avec rapport de recherche internauionale.

(71) DWposant (pour tous les Las d&sign6s sauf US): STEDIM S.A. [FR/FR]; Zone Industrielle de Saint-Mitre, F-13400 Aubagne (FR).

(72) Inventeur; et Inventeur/D~posant (US seulement): VALLOT, Bernard [FR/FR]; 68, traverse Fort-Fouque, F-13012 Marseille (FR).

(74) Mandataire: CABINET ROMAN; 35, rue Paradis, Bonte postale 2224, F-13208 Marseille CMex 01 (FR).

(54) Title: RADIOFREQUENCY WELDING ELECTRODE FOR MtJLTICOMPARTMENT PLASTIC FILM BAGS INTENDED FOR MEDICAL USE, AND BAGS PRODUCED WITHI SAME (54) Titre: ELECTRODE DE SOUDAGE A HAUTE FREQUENCE POUR POCHES MULTICOMPARTIMENTS A USAGE MEDICAL EN FILM PLASTIQUE, Er POCHES REALISEES GRACE A CE MATERIEL (57) Abstract The object Gf the present invention is a radiofirequency welding electrode for multicompartinent plastic film bags for medical use, and the bags produced with this equipment.

According to this method, the multicompartment bags (1) are produced by joining two suitable flexible plastic films by radiofr-equency welding with electrodes bearing specially shaped, raised indentations for producing exceptionally wide welded parts (16) without bt~ds of excess material at the points where the weld lines cross the sealing area between compartments 3, The invention concerns the production of bags particularly intended for use in medical perfusion, and including at least two compartments containing products that should be mixed only at the time of use.

(57) Abr&,A La prisente invention a pour objet une 6lechrode 0k soudage A haute frdquence pour poches. multicompartinents A usage medical en film plastique, ainsi que les poches abtenues gralce A ce materiel. Le proc&16 consiste &L fabriquer les poches multicompartiments par assemblage de deux films plastique souples appropri~s par soudage A haute fr6quence au moyen d'6lectrodes comportant des empreintes en relief de forme particuli~re permettant de cr~er des parties soud~es (16) fortement 61argies et depourvues de bourrelets ,d'exc~s de matitre aux points oia les lignes de soudure croisent in zone d'6tanch6it6 entre compaxtiments 3, Elle est destin&e A la fabrication de poches utilis~es en particulier pour la perfusion m~licale et comportant au mains deux compartiments contenant des produits ne~devant 8tre mdlangds qu'au moment de lour utilisation.

I HIGH FREQUENCY WFELDING ElECTRODE FOR MULTICOMPARTMENT PLASTIC FIIM BAGS INTENDED FOR MEDICAL USE, AND BAGS PRODUCED !WITH TIIS MATERIAL The aim of the present invention is a high frequency welding electrode for producing multicompartment plastic film bags, as well as the bags obtained from this material.

It is intended for the fabrication of bags used in particular for medical perfusion and containing at least two compartments which contain products which are not mixed prior to the moment of their use.

In this type of of bag, the compartments (two or more), which contain the products forming the composition to be used in the perfusion are insulated from each other in a water tight manner by means of a pressure element pushing the two walls of the bag one against the other. This element can be withdrawn at the propitious moment by the operator which has the effect of allowing the products to mix at the desired moment.

In most cases these bags are produced starting with two sheets of plastic and assembled by heat welding. This technique has the disadvantage of being hard to control and of not always permitting insertion into the parting line of the filling and discharge tubes which makes the fabrication more complex and therefore more expensive, the placing of these tubes generally needing to be carried out during the supplementary operations by means of small patches welded onto the walls of the bags.

These disadvantages disappear when using high frequency welding which can be perfectly controlled and which permits not MODIFIED SHEET i I only the insertion of the tubes into the parting line during welding but equally permits the use of films which are especially adapted to medical use, particularly ehtylene vinyl acetate (EVA), or multilayer water proofing materials of which one external layer has specific water proofing functions.

However, it is a normal consequence of high frequency welding that internal folds are formed along the welds, which are not deleterious in case of single compartment bags, rather the contrary. In effect, these folds normally represent one of the marked advantages of high frequency welding: they notably improve the water tightness and solidity of the welds and permit an effective visual control of the latter.

But in the case of the multicompartment bags, the folds make the water tightness between compartments very uncertain, even if high pressure is applied. In any case the the pressure which would need to be applied to obtain a satisfactory water tightness is incompatible with the low shrinkage force of the closing element which is compatible with current practice.

Patent No. GB 2 096 569 describes a high frequency electrode which is intended for the fabrication of multicompartment plastic film bags, and which contain enlarged lateral impressions which permit obtaining on the peripheral weld lines, parts without internal folds at the points where they cross the water tightness zones between two compartments. These impressions are formned of flat semi-circular elements surrounded by a piece of insulating material, the purpose of which is to prevent the fusion of the plastic films around the said impressions, the excess material flowing MODIFIED SHEET I back in a peripheral channel of the electrode, provided for this purpose. These pieces of insulating material and the peripheral channel make the construction of the whole system complex and make a very rigorous control of the heating parameters necessary so as to avoid blocking the channel and the degradation of the insulating pieces.

The process according to the present invention eliminates all these disadvantages. In effect, it makes it possible to produce multicompartment bags from plastic film of high quality ensuring a perfect water tightness between the compartments by means of very simple pressure elements and of a very simple manipulation.

The process consists of the fabrication of multicompartment bags by assembling of two flexible plastic films which are suitable for high frequency welding by means of electrodes containing relief impressions of the particular shape permittinng the creation of strongly enlarged welded parts and free from folds of excess material at the points where the weld lines cross the water tightness zones between compartments.

In the attached drawings, which are given as non-limiting examples of one form of execution of the aim of the invention: figure 1 represents a bag with three compartments with the water tightness system in place, figure 2 represents the same bag after shrinkage of the water tightness system, figure 3 is an enlarged transverse cross section, along the arraws A-A of figure 1, of the water tightness zone.

figure 4 shows, on a different scale, a high frequncy welding electrode seen from above, MODIFIED SHEET y^-1- Q( ^w c e figure 5 is an enlarged transverse cross section of the welding line following the arrows B-B of figure 2 and figure 6 is a transverse cross section of the broadened welding zone following the arrows C-C of figure 2 and of figure 4, showing one of the relief impressions during welding.

The figures described refer, under the title of example, to the fabrication of a perfusion bag 1 with three compartments 2, 3, 4.

During the fabrication these compartments are insulated in a water tight fashion by means of a cylindrical springy rod and by a rigid bar 6 with a semi-circular cross section between which the two walls 7, 8 of bag 1 are clamped. Before being used the bags are prepared by filling the compartments with the aid of filling tubes 9 which are buhsequently hermetically sealed. The bags can then be stored as long as necessary without there being a risk that the products contained in the different compartments can come into contact with each other When putting it into service the bag is placed on a adequate bracket by means of an eyelet 10 which has been provided for this purpose on its top, and the perfusion conduit is then connected to the discharge tube 11 which is located at the bottom of the lower compartment 4. The flexible rod 5, which is sufficiently long to go beyond one of the sides of the bag, is then withdrawn which allows the freeing of the rigid bar 6 and thus permits the walls 7, 8 to recede one from the other with the three compartments thus being placed in communication The products mix and perfusion can begin.

MODIFIED SHEET The fabrication of the bag 1 starts with two flexible films of a plastic which can be high frequency welded and adapted for medical use. These films are placed one against the other and spread between the electrode 12 and the plate of a machine for welding by a high frequency electrical field. The cutting and assembly of the two films are carried out in a single operation with the aid of a cutting edge provided along the whole periphery of the electrode.

The latter contains relief impressions which are broadened laterally at 13, 13' and centrally at 14 placed at the spot where the welding lines 16 cross the water tightness zone 17 between compartments.

These impressions have the purpose of broadening the welding line at these locations, by creating "crimped paving" 18, centrally and 19 laterally without internal folds 20 which are normally created by this technique of welding along the weldin- lines (cf The profile of the impressions is designed to allow "the propping up" of the excess material due to the pressure exercised during welding in such a fashion as to avoid the creation of folds For this purpose the surface 15 (figure 6) which is in contact with the plastic film 7 is not plane but rises progressively toward the interior of the bag, following a rounded curve.

The impressions 13, 14 can be integrated into the electrode 12, but they will for preference be related and fixed to the side of the latter, which makes the machining of the said impressions and the maintainance of the electrodes easier.

The design of the crimped paving, and therefore of the impressions, will be adapted to the material used, the conditions of execution and to the type of bag to be produced. However, they will, for preference, have a drop or semi-drop like shape depending on whether they will be central or lateral (figures 2 and 4).

MODIFIED SHEET

V\

4.

The lateral pavings can equally have a semi-dihmond shape as shown in references 13' of figure 4 and 19' of figure 2. In any case these figures will be sufficiently rounded so as not to interfere with the flow of products contained in the bag, and sufficiently large to allow the use of a rigid rod 6 of a length which is slightly less than the size of the bag, so as to avoid interfering with the handling of the said bag.

In the top and bottom parts of the bag the electrode 12 is doubled and contains interruptions 21 and 22 which permit the insertion into the parting line and the welding of the filling tubes 9 and of the discharge tubes 10, these operations being realisable at another work station.

The total operations can be carried out continuously and fully automatic, which will make it possible to achieve a very competitive cost of fabrication.

The plastic films 7, 8 used, will, to advantage, be made of ethylene vinyl acetate (EVA) or of a multilayer insulating material, one of the layers of which has tightness properties with respect to gases and water vapour.

T

Iowever, other material which can be welded by high frequency can be used as a function of the nature of the solutions which are to be stored in the bags.

The bag described contains three compartments, but it is evident that the process can be applied perfectly to bags which have more than three compartments. In the same way it can be applied to the production of bags intended for other uses than medical perfusion.

MODIFIED SHEET

PN

The positioning of various constituent elements gives the aim of the invention a maximum of useful applications, which have not, to this day, been obtained with similar applications.

MODIFIED SHEET 0