Method of forming a container

Abstract: The present invention relates to a method of forming a container (10) having an upper end neck (14) with a cylindrical barrel for receiving a withdrawal instrument (25, 46), and having a collar (20) internally projecting at the lower portion thereof, and terminating with a stop (21) therebeneath to accurately gauge the penetration of the withdrawal instrument (25, 46), characterised by the steps of forming a mandrel for insertion into a parison which has been partially blown having an upper neck portion in which a stop is provided above the base of the neck, forming a friction fit ring from a recess in the mandrel and proportioning a radius and draft angle which permit the mandrel to be withdrawn from the thus-formed product without damaging the ring and stop but after they have been sufficiently formed to permit the withdrawal of the mandrel.

Description: This invention relates to sealed containers usually for sterile storing and dispensing of fluids. The size of the container can vary from 0.4 millilitres to 500 millilitres or more. The containers may contain an injectable serum, intravenous fluids, fluid for use in diagnostics and other fluids. Specifically, the apparatus relates to forming the container neck to receive a withdrawal insert sealed to the neck which can also accomplish full withdrawal. The method relates to forming the container and the sealed withdrawal of fluids from the containers. U.S. Patents Nos. 4,643,309, 4,540,542, 4,239,726 and 4,298,045 all relate to withdrawing a fluid from a container. Invariably, the containers shown in US-A-4,643,309 accept a syringe tapered conical end engaged by a tapered female recess in the neck of a vessel or phial, and the two are related by a friction fit of zero tolerance as to the tapered angle of each, most normally being approximately 2°. With the larger containers as shown in US-A 4,239,726 and 4,298,045, a tapered spike withdraws the fluid from a tapered conical opening. The disadvantage of such tapered inserts are numerous. First, the fit is along a frustoconical surface such as the upper two-thirds of a cone which fits into a container which is comparable to the upper two-thirds of another cone. Second, the fit is frictional and not interference which could permit leakage. Third, the inserts are of varying lengths and extend into the container beyond the neck and hence cannot achieve maximum or effective total withdrawal. The fit is, therefore, frictional and that of a repository as distinguished from lockingly engaged by a predetermined interference seal. In addition, with the type of a phial as illustrated in US-A-4,643,309 there is no provision for determining accurately the depth to which the insert is inserted into the container. If the insertion is not predetermined, the extent of the insertion may be longer or shorter than that desired. Also, when inverted, leakage can occur. If the tip of the withdrawal insert penetrates the container beyond its neck, some fluid may be trapped and cannot be withdrawn. US-A-4,540,542 relates to a unitary container, such as a vial or ampoule, hermetically sealed with a top or closure structure connected to the container by means of a frangible web. Therefore, what is desired is a container which is formed to accept a withdrawal insert which will guide the same into position and secure it with a tight seal which will overcome leaks attributable to scratches that may occur in the manufacturing process or in the insertion process. The structure should also ensure that the withdrawal member is inserted to a given position so that in withdrawing the solution effectively the entirety of the contents will be withdrawn. In addition, the above should be achieved through a manufacturing process in which conventional blow moulding and/or blow/fill seal equipment is employed. Accordingly, the present invention provides a method of forming a sterile fluid container by blow moulding a thermoplastic material, which container has a neck with a cylindrical barrel for receiving a withdrawal instrument and which neck has a friction fit ring internally projecting at the lower portion thereof, and which neck terminates with a stop to accurately determine the penetration of the withdrawal instrument, characterized by the steps of inserting a mandrel into a parison which has been partially blown, the mandrel having a neck forming portion with an upper portion terminating in a stop forming portion and a lower portion in which a friction fit ring forming portion is formed from a recess in the mandrel and pre-proportioning a radius and draft angle on the mandrel which permit the mandrel to be withdrawn from the thus-formed product without damaging the friction fit ring and stop but after the ring and stop have, been sufficiently formed to permit the withdrawal of the mandrel. In a preferred aspect the upper neck stop is a seating ring. For a better understanding of the invention, and to show how the same may be carried into effect, reference will now be made, by way of example, to the accompanying drawings, in which:- Figure 1 is a front view of a typical intravenous solution dispenser, the container part thereof being . formed by the method according to the present invention; Figure 2 is an enlarged cross-sectional view of a neck portion of a withdrawal element of the container shown in Figure 1; Figure 3 is an enlarged cross-sectional view of a plug and tube used to insert into the container neck of Figure 2; Figure 4 is a transverse sectional view taken along line 4-4 of Figure 2 and showing an alternative embodiment in which a flat is employed in order to orientate the insert; and Figure 5 is another transverse sectional view showing the container neck, but used in conjunction with a conical Luer tip made in accordance with American National Standard NC/HIMA MD 70.1-1983. The first embodiment is shown in conjunction with a container 10 as it appears in Figure 1. The container 10 is provided with a seal tab 11, a body portion 12 and a hanger 13. The seal tab 11 is secured to a body neck 14 by means of a frangible web 15. In opening, the seal tab is torn away from the neck 14 when the frangible web 15 is broken. The container 10 is hermetically sealed and normally has a plurality of removable closures 11, 16 for containing and dispensing sterile solutions. The removable closures 11, 16 are integral with the container 10, which comprises a sealed elongate shell or body 12 of a thermoplastic material which has at least one access port at each end of the shell, a neck integral with the shell and surrounding each access port and a removable cap structure over the access ports. These constitute e.g. the closures 11, 16 and the frangible annular webs 15, which are integral e.g. with the removable cap 11 and neck 14. At least one of the neck portions is provided with a bore of predetermined controlled dimensions and is adapted to receive a draining spike or a similar means for withdrawing the contents of the container. In the embodiment shown in Figure 1, I.D. control port 14 is provided and is made accessible by removing the cap 11 when the frangible web 15 is broken. Figure 2 shows that the neck 14 terminates at the frangible web 15 at its lower portion and a reinforcing web 18 is provided to strengthen the neck 14 where it joins the body 12 of the container 10. An interference collar 20 and a seating ring 21 are provided inside the neck. In order to withdraw fluid through the initial opening aperture 19, a plug 25, as shown in Figure 3, is employed. The plug 25 is secured to a withdrawal tube 26 which is press-fitted over the plug tube insert 31 and the tube 26 abuts the tube in seat 32 on the control ring 28. The neck insert 30 has an upper surface 38 which is a seating ring face. It engages the portion of the neck 14 from which the frangible web 15 (see Figure 2) has been removed. The plug 25 is provided with an aperture 29 which traverses the control ring 28. A nick 35 is provided around the neck insert 30 to receive and nest as an interference fit the interference collar 20 of the neck 14 shown in Figure 2. The neck insert end 36 of the plug 25 has a sealing ring face 38 which is snugly positioned, when inserted, against the seating ring 21 of the neck 14. A modification as shown in Figure 4 is available if it is desired to orientate the insert into the neck 14 of the container 10. There it will be seen that this orientation is provided by means of an internal flat 40 on the neck which engages a flat 41 on the insert. The flexibility and adaptability of the construction is illustrated in Figure 5, where the container 10' may be smaller than container 10 of Figure 1, such as 0.4 millilitres or larger. It is utilised with a Luer slip fitting 45 such as identified in American National Standard and C/HIMA MD 70.1-1983. The Luer slip fitting 45 is provided with a Luer conical tip 46 and has a Luer tip end 48. Upon inserting the Luer conical tip 46 into the neck 14 an interference is occasioned by the dimensional provisions for the collar 20. Once the tip 46 is fully inserted to where the end of the tip 46 sits on top of the seating ring 21, it is ready to withdraw the fluid from the container 10. When withdrawal does take place, the container can be held horizontally, but ultimately tipped upwards towards the vertical to the end that all of the contents will flow into the aperture 50 of the conical Luer tip 46. At the same time, not only is full withdrawal assured, but sealing between the container and the Luer slip fitting 45 is ensured at two portions, firstly where the end 48 of the Luer tip seats on the seating ring 21, and secondly where the interference fit is provided by the circumferential locking between the interference collar 20 and the Luer conical tip 46. While dimensions do not necessarily form a part of the invention, they do illustrate the problems surrounded by the invention and how they were solved, and also the various proportions. The dimensions are not intended to be limiting, but rather exemplary of certain commercial adaptations. The dimensions also form a frame of reference for gauging proportions. The commercial type container 10 shown in Figure 1 has a 500 millilitre capacity. The dimension from the median portion of the interference collar 20 to the seating ring 21 is 4 millimetres (0.15 inches). It will be seen that the interior narrow dimension of the interference collar 20 is 3.962 millimetres (0.156"). Turning now to the dimensions of the plug 25, the neck insert is 4.293 millimetres (0.169") and the depth of the neck 35 gives it a diameter of 4.039 millimetres (0.159") thus insuring an interference fit of 0.77 millimetres. The distance from the ring seat face 38 of the neck insert 30 to the centre of the neck 35 is identical with the counterpart dimension in the neck 14 of the container 10. The plug 25 diameter can be readily increased to twice or more the dimension set forth. Turning now to Figure 5, the dimensions of the distance between the interference collar 20 and the seating ring 21 are identical to that shown in the embodiment of Figure 2, with the exception that the overall distance from the seating ring 21 to the frangible web end portion 15 of the neck 14 is 6.350 millimetres (0.250"). It will also be appreciated that the dimensions are in part controlled by the ANSI standard for the Luer slip fitting ANSI/NIMAND70.11983. The constriction portion of the sealing collar 20 is 3.962 millimetres (0.156"), the same as with the embodiment of Figure 2, providing for a snug interference fit. Where the conical Luer tip end 48 seats upon the seating ring 21, the outside diameter of the Luer tip end 48 is 4.027 millimetres (0.1585") whereas the interior diameter of the seating ring 21 is 4.293 millimetres (0.169") thus providing for a gap of 0.166 millimetres to ensure that the conical tip engages only the interference collar 20 and not the balance of the conical surface of the conical Luer tip 46. This ensures a very tight interference fit between the interference fit collar 20, and the conical Luer tip 46. Also, when the end 48 of the conical Luer tip 46 is seated on the seating ring 21, the collar not only provides a second seal, but also a dimensional "jig" whereby the Luer tip end 48 is held snugly and vice-like against the seating ring 21 in further fluid sealed engagement. In operation, the embodiment of Figure 5 is comparable to that of Figures 1-3 in that the insert is positioned inside the neck until its end is secured against the seating ring 21. Thereafter, the contents are withdrawn, and towards the end of the withdrawal, the container is held horizontally or inverted if need be in order to accomplish full withdrawal of the contained solution. After full withdrawal, the insert is removed. The present method, from a standpoint of forming the container 10, is disclosed and described in applicant's earlier U.S. Patent No. 4,239,726, more specifically as illustrated in Figures 7-10 thereof. While the same method is employed in forming the container and the neck, it is modified to the extent that a mandrel which is used is formed so that its cross-section is the same as the aperture 18 but recessed in order to form the interference collar 20. Also the lower end of the mandrel is dimensioned to form the seating ring 21. The same are proportioned to permit the mandrel, despite its interfering fit with the neck 14, to withdraw from the aperture 18 without disturbing the configuration of the already-formed interference collar 20 and the seating rings 21. In the use of the container 10, 10' the seal tab 11, which is common to both constructions shown, is removed and thereafter the plug 25 which is used with a tube 26 is inserted or Luer tip cone 46 of a syringe. With both the plug 25 or 45, the Luer tip 48 inserted and pressed into position to a point where their respective ends and the seat engaging ends bottom out of the seating ring 21. This step is important because once the relationship between the end of the withdrawal instrument and the seating ring is established as to physical contact, when the container is inverted the entire contents have no other place to go than into syringe or the plug or the tube. This ensures effective total withdrawal of the fluid while at the same time employing an absolute interference fit seal around the body portion of the withdrawal instrument. A further and related aspect of construction as shown in Figure 4 relates to the positioning a flat or otherwise providing for an asymmetrical withdrawal instrument so that positive orientation may be made of the withdrawal instrument. Thus, by providing a neck of a container with a non-tapered cylindrical upper drain portion and a frictional interference fit collar type gripper for the withdrawal member, this results in tight interference fit. Also total effective withdrawal of the contents of the container is promoted by providing a ring like stop or seat at the bottom of the neck. In essence, a double seal is achieved with the further advantage of total withdrawal of the contained fluid. The construction also will accommodate flaws and defects in the manufacture of the withdrawal member or the drain portion resulting from scratches which will otherwise permit leakage upon withdrawal of the contents. It will be appreciated that the container is made by a method by which the mandrel for insertion in the neck has a lower end portion providing a seating ring, and an upper portion defining the interior portion, with an interference collar protruding inwardly in a portion spaced from the lower end portion. The radius and draft angle permits the mandrel to be withdrawn from the moulded plastics product without deforming or damaging the same, but only after the neck of the container including an internal interference fit collar and ring seat have been shaped.

Claims: A method of forming a sterile fluid container by blow moulding a thermoplastic material, which container has a neck (14) with a cylindrical barrel (18) for receiving a withdrawal instrument and which neck has a friction fit ring (20) internally projecting at the lower portion thereof, and which neck terminates with a stop (21) to accurately determine the penetration of the withdrawal instrument, characterized by the steps of inserting a mandrel into a parison which has been partially blown, the mandrel having a neck forming portion with an upper portion terminating in a stop forming portion and a lower portion in which a friction fit ring forming portion is formed from a recess in the mandrel and pre-proportioning a radius and draft angle on the mandrel which permit the mandrel to be withdrawn from the thus-formed product without damaging the friction fit ring (20) and stop (21) but after the ring and stop have been sufficiently formed to permit the withdrawal of the mandrel. A method as claimed in claim 1 in which the stop (21) is a seating ring.

Inventors: WEILER GERHARD H, WEILER, GERHARD H.
Applicants: AUTOMATIC LIQUID PACKAGING, AUTOMATIC LIQUID PACKAGING, INC.
Application year: 1993
Main classification: B29C49
IPC codes: A61J1, B29C49, B29C57