Apparatus for Filling Self-Sealing Tubes

this invention relates to an apparatus for filling tubes.

VACUTAINER (registered trademark) tubes comprise a tube per se and a self-sealing stoppering or closure means. The closure means is made from a material which, on the one hand, seals the tube so as to prevent the interchange of liquids, gases or microscopic particles between the inside and the outside of the tube and on the other hand may be pierced by a syringe needle so as to admit a blood sample taken from a human or animal blood vessel. To assist in the sampling of the blood, the atmosphere of the VACUTAINER or self-sealing stoppered tube is at a reduced pressure relative to atmosphere. Once the needle as been removed from the closure means, the tube is again automatically sealed by virtue of the composition of the closure means.

It is an object of the present invention to utilize VACUTAINER tubes or self-sealing tubes in a new way for the purpose of holding a preset volume of a fluid initially in liquid form but which subsequently solidifies. It is a further object of the present invention to provide tubes containing the fluid which is sterile before, during and after placement thereof in the tube.

The invention, therefore, provides an apparatus for introducing a fluid into a tube having a self-sealing closure means which apparatus comprises means for releasably clamping the tube at a fluid injecting station; an injector device including a hollow needle; and means for enabling the needle to penetrate the closure means for introducing a charge of fluid into the tube and for enabling the needle to be withdrawn from the tube.

The invention also relates to a method of introducing a fluid into a tube having a self-sealing closure means which method comprises clamping the tube at a fluid injecting station; allowing a hollow needle to penetrate the closure means; introducing a charge of fluid into the tube via the needle; removing the needle from the tube; and releasing the tube.

The invention will be understood from the following description of a preferred embodiment thereof given by way of example only and with reference to the accompanying drawings in which:

FIG. 1 is a perspective view of a first embodiment of an apparatus according to the invention in a first condition of use;

FIG. 2 is a perspective view of the apparatus of FIG. 1 in a second condition of use;

FIGS. 3 through 6 are perspective views of part of the apparatus of FIG. 1 in varying positions of use;

FIG. 7 is a cross-sectional view of a tube used with the apparatus of FIG. 1 of the drawings; and

FIG. 8 is a perspective view of a second embodiment of an apparatus according to the invention.

Referring now to the drawings, there is shown an apparatus 10 according to the invention which apparatus 10 comprises a conveyor system 11 for conveying tubes 12, each having a self-sealing closure means 30, sequentially to a station. The conveyor system 11 includes a base 13b having a shape conforming to one of the tubes 12. At the station, there is provided a clamping means 13 having a clamp 13a of substantially hemi-tubular construction for reciprocal movement from an elevated condition (FIG. 1) to a clamping position (FIG. 2).

The apparatus 10 further comprises a reservoir 14, a housing 15 and a needle support means 16. The needle support means 16, which includes a hollow needle 17, is connected to a metering means mounted in a housing 15 by a flexible pipe 18. Also attached to the needle support means 16 is an arm 19 adapted for reciprocal movement towards and away from the conveyor system 11 by a motor 25 or the like.

The metering means comprises a peristaltic pump of a known type which acts on the tbe 18 thereby enabling the delivery of a predetermined volume of fluid.

In use, a plurality of tubes 12 each having a respective closure means 30 is placed on the conveyor system 11 for sequential feeding to the station. When a tube 12a arrives at the station, the conveyor system 11 stops, the clamping means 13 lowers the clamp 13a to the clamping condition so as to prevent undue movement of the tube 12a. The arm 19 moves in the direction of the tube 12a to enable the hollow needle 17 to penetrate the closure means 30 of the tube 12a. Following penetration, the peristaltic pump in housing 15 is actuated to enable a predetermined volume of fluid to enter the tube 12a. Following the introduction of the required volume of fluid, the peristaltic pump is deactuated, and the arm 19 moves away from the tube 12a to release the needle 17 from the closure means 30. The clamping means 13 is elevated to release the tube 12a and the conveyor system 11 indexes to the right a distance sufficient to bring the next tube 12b to the station for the process to repeat.

The closure means 30 is made from a material which on the one hand seals the atmosphere of the tube 12 to prevent gaseous, liquid or microscopic particle from interchanging therethrough. However, the material may be penetrated by the needle 17. Following penetration and removal of the needle 17, the closure means 30 automatically reseals the tube 12.

The apparatus 10 according to the invention may be used under sterile conditions for the preparation of, for example, agar. In that event, the tubes 12 are evacuated to a pressure of about 45kPa and made sterile. The thermostable constituents of the agar are solublished and subjected to a temperature of about 120.degree. C. at about 200kPa (2atm) for about 30 minutes in an autoclavable container which, if desired, can contain a batch of the tubes 12 previously evacuated and stoppered by respective closure means 30. The temperature of the constituents is lowered to about 50.degree. C. and mixed with an appropriate quantity of sterile blood or other thermolabile substances. The mixture, which constitutes the agar, is placed in the previously sterile reservoir 14 and maintained at a temperature of about 50.degree. C by a heater 14a. The tube 18, which connects the reservoir 14 with the needle 17, together with the needle 17 are also sterile.

Upon penetration of the needle 17 through the closure means 30, the negative pressure in the tube 12 assists in the placement of the agar in the tube 12. No venting of the tube 12 is required and hence there is no loss in the sterility of the contents of the tube 12. Following withdrawal of the needle 17 from the tube 12, a negative pressure of about 25kPa will still be present in the tube 12 relative to atmosphere. This partial vacuum can assist in the growth of microaerophilic bacteria.

Sterility can be checked in sample tubes of a batch by piercing the closure means 30 with a needle having a tube leading into water. Rapid respiration of the water will indicate that a partial vacuum was present in the tube.

The apparatus 10 according to the invention may be used with non-evacuated tubes 12 also under sterile conditions. To enable the peristaltic pump to operate in conjunction with non-evacuated stoppered tubes 12, the needle support means 16 includes a second hollow needle 17a in parallel, spaced apart relationship to the needle 17 as shown in FIG. 8 of the drawings. The second needle is connected via a tube 18a back to the reservoir 14. The needle 17a and associated tube 18a are also sterile. In use, both needes 17, 17a penetrate the closure means 30. The second needle 17a enables venting of the tube 30 without loss of sterility. If desired, the reservoir 15 may be vented to the atmosphere via an opening having a suitable filter therein such as a 0.22 micron filter.

The volume of fluid dispensed into the tube 12a is about 4ml with an adjustable flow rate depending on the velocity of the liquid. The volume is adjustable by virtue of the peristaltic pump.

The apparatus 10 enables quick, easy and sterile filling of tubes 12 with a suitable fluid for subsequent use.

In particular, and in regard to FIG. 7 of the drawings, the injection of the agar 20 into the tubes 12 while in the horizontal position and subsequently maintaining the tubes 12 in the horizontal condition until the agar 20 has set will provide an agar surface area of a significant size when compared with the placing of agar in tubes 12 held in a vertical condition. It will further be appreciated that the tube 12 need not necessarily be placed in the horizontal condition when in use for bacteriological culture analysis but, with regard to the solidified agar 20 may be placed in the vertical position.

The apparatus 10 may, therefore, be used in a non-sterile but relatively clean area. The apparatus is particularly useful where particle-free loading areas would be difficult or uneconomic to implement.

The invention is not limited by or to the specific embodiment described which can undergo considerable variation without departing from the scope of the invention.