US3022886A - Compressible container for liquids - Google Patents

Description

Feb. 27, 1962 B. JARNHKLL 3,022,886

COMPRESSIBLE CONTAINER F OR LIQUIDS Filed May 7, 1958 INVENTOR.

8mm Jan/m4 11 TTORNE Y United States Patent M 3,022,886 COMPRESSIBLE CONTAINER FOR LIQUIDS Berti] Jiirnh'all, Sodertalje, Sweden, assignor to Aktiebolaget Astra, Apotekarnes Kemiska Fabriker, a company of Sweden Filed May 7, 1958, Ser. No. 733,610 Claims priority. application Sweden May 9, 1957 6 Claims. (Cl. 206-56) The present invention refers to a compressible container for liquids, particularly a container which is intended to be used as an ampul in a hypodermic syringe.

It is known to make liquid-filled containers by compressing and sealing together the walls of a liquid-filled tube made from a flexible material, along narrow zones perpendicular to the longitudinal direction of the tube. This process may be carried out continuously by forming a sheet of a suitable material into the shape of a tube and sealing the edges of the strip to each other, and continuously introducing the liquid into said tube. The separate containers manufactured from said tube may be described as being either pillow-shaped or tetrahedron-shaped. The tetrahedronal containers are made by compressing and sealing the tube along narrow zones which are alternatingly perpendicular to each other.

The emptying of such a tetrahedronal container does not involve any difliculty as long as the liquid may be poured out of the container. If the liquid is to be pressed out, for instance, in a hypodermic syringe, the walls of the container become creased in an irregular way, so that it is diflicut to press out the whole amount of liquid.

It is an obiect of this invention to provide a container which is a modification of the known tetrahedronal container and which may be compressed so that such an irre ular creasing does not occur. It is a further object of the invention to provide a container which may be manufactured in a continuous method at a low cost. It is another obiect of the invention to provide a container which is somewhat resilient or elastic. so that it has a tendenc after having been compressed. to go back to its original shape. It is a special ob ect of the invention to provide a container which may be used as ampul in a hypodermic syringe of the kind in which a compressible am ul is pressed by means of a plunger against the outlet end of the syringe, and a sharp point is provided in said front wall so as to puncture the ampul so that the liquid is pressed through the injection needle. The compressible ampuls hitherto used for this purpose have usually been accordion-shaped. Only a few materials. however, have been suitable for the manufacture of such ampul. and it has been necessary to manufacture these ampuls by discontinuous methods through blowing. The ampul according to the present invention may be manufactured in a continuous method and from a large variety of materials in sheets.

The container according to the present invention is ch racterized in consisting of at least two substantially tetrahedronal receptacles made from a flexible material and being connected to each other along one edge of the tetrahedron and communicating with each other at said common edge, the distance between said common edge to the edge which is perpendicular thereto, being less than the corresponding distance, i.e. the altitude, of a regular tetrahedron.

The invention will hereinafter be described with reference to the drawing which shows. as an example, a container consisting of four tetrahedronal receptacles.

The container illustrated in the drawing has been manufactured from a sheet of a flexible material, such as polvvinvl chloride or paper, which on one or both sides is coated with another plastic material. The sheet is bent to form a tube and the overlapping edges of the 3,022,886 Patented Feb. 27, 1962 the narrow zones 2, 3 and 4 are sealed together on a few points, for instance at the ends of the narrowzones,

as indicated at 6. It is to be emphasized, however, that these sealed places do not prevent the passage of liquid from one tetrahedronal receptacle to the other. Finally, the walls of the tube are compressed and sealed by means of heat sealing members along a narrow zone 5 which is parallel with zones 1 and 3, and the package thus formed, which consists of four tetrahedronal receptacles, is separated from the remaining portion of the tube.

The distance between two narrow zones is so chosen that each narrow zone is longer than the other edges of the tetrahedrons, or in other words, the distance between the edge which joins the tetrahedron with the adiacent tetrahedron and the edge perpendicular thereto, shall be smaller than the corresponding distance of a regular tetrahedron, that is a tetrahedron bounded by four equilateral triangles.

It is clear to any person skilled in this art that the manufacture described may be carried out as a continuous process, if desired.

The described welded places 6 may be dispensed with if a materia is chosen in which permanent folds may be formed, and which yet has a certain degree of resiliency. A laminated material is useful for this purpose, which consists of at least one layer which is impermeable to liquids and gases, and at least one layer which is resilient to a certain extent, and which forms sharp and permanent folds when the zones 2. 3 and 4 are compressed by means of cold compressing members.

The material which is to form permanent folds may be such a plastic, the yield value of which is exceeded at the pressure used for compressing the narrow zones 2, 3 and 4. Thereby, the folds become permanent, and remain after the pressure has been released. If it is desired to reach the yield value at a lower pressure, the compressing members may be somewhat heated, but of course not to a temperature which causes the compressed tube walls to be sealed. An excellent material for this purpose is cellulose acetate, but it was found that other plastics having a modulus of elasticity between 1000 and 50000 kgs./cm. may also be used, such as polyvinyl chloride, regenerated cellulose and polyethyleneterephthalate.

It has unexpectedly been found that a laminated material consisting of two or more layers of the same material is superior to one homogeneous layer of the same material having the same total thickness.

The impermeable layer may consist of two layers, one of which is impermeable to water and water vapour, and the other one is impermeable to air and other gases. Polyethylene, trifluoro-monochlore-polyethylene, polyethylene-terephthalate, regenerated cellulose, polyvinylidone-chloride, rubber-hydrochloride and polypropylene are materials having an excellent impermeability to water and Water vapour. Regenerated cellulose, polyvinylidene chloride and polyethylene-terephthalate have a good impermeability to air and other gases.

A laminated material may, for example, consist of a polyethylene foil having a thickness of 0.05 millimeter, which is combined in a manner known per so with a moisture-proof regenerated cellulose foil having a thickness of 0.05 millimeter. The laminating agent is prefertional layer having, for instance, a celluloseacetate, using polyisobutylene as laminating agent.

A container according to the present invention may be compressed longitudinally without any folds being formed in an uncontrolled way. The container also has a certain degree of elasticity. This is useful if it is desired to respire" during the injection, that is to say, to draw back liquid into the ampul, for instance in order to observe Whether the point of the needle has penetrated into a vein.

What is claimed is:

1. A compressible ampul adapted to be liquid-containing and insertable into a hypodermic syringe to be compressed therein to expel liquid content therefrom, further characterized in consisting of a series of at least two consecutive substantially tetrahedronal-shaped receptacles whose walls are of a flexible and somewhat resilient material, and with each two consecutive receptacles being connected to one another along a common edge of such two tetrahedrons and communicating with one another through said common edge; and which receptacles extending in a relatively straight line have longitudinally spaced apart from each side of said common edge respectively another edge, which such other edges lie in a plane that is normal to a plane passing through. said common edge andextending lengthwise through the ampul; and with the distance from said common edge to each of said two other edges being less than the corre sponding distance in a regular tetrahedron; said ampul being compressible within a hypodermic syringe by hand pressure as ordinarily applied thereto and thereby to expel its liquid content through the needle of such syringe after being punctured by the inner end of the needle.

2. A compressible container as claimed in claim 1, wherein. the two opposedv walls. forming the common edge are sealed together at a plurality of spaced apart places.

3. A compressible container as claimed in claim 2, wherein the said opposing walls are sealed together at places within the range of from near the ends of said common edge to said ends.

4. A compressible container as claimed in claim 1, characterized in. having its walls composed of a flexible material which hasthe quality of forming sharp, permanent folds when being folded underpressure.

5. A compressible container as claimed in claim 4, characterized in having its walls composed of a flexible, laminated material consisting of at least two layers, one of which being impermeable'to liquids and gases, the other having the quality of forming sharp, permanent folds when being foldedunder pressure;

6. A compressible container as claimed in claim 5, characterized in having its walls composed of a flexible, laminated material consisting of at least one layer of polyethylene and: at least one layer of cellulose acetate.

References Cited in the-file of this patent V UNITED STATES PATENTS

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