WO1997047727A1

WO1997047727A1 - Sealing device for a fluid container

Info

Publication number: WO1997047727A1
Application number: PCT/GB1997/001529
Authority: WO
Inventors: Anthony Hugh Carr
Original assignee: Oxoid Limited
Priority date: 1996-06-11
Filing date: 1997-06-09
Publication date: 1997-12-18

Abstract

A container unit comprising a fluid containing container (10) and fitted thereto a sealing device which comprises a rubber septum (12) and a septum puncturing device (20). The sealing device is preferably adapted to receive a measurement device (24) which automatically causes the septum to be punctured when it is fitted, for example to place the interior of the bottle in communication with the measurement device through a hollow needle (30).

Description

Title: Sealing Device for a Fluid Container

Field of the Invention

This invention relates to a sealing device for a fluid container, to the combination of said device with the container, and to a method of monitoring the container contents.

Prior Art

Culture bottles are widely used in laboratories and hospitals in the culturing of samples, to detect the presence of microorganisms. At present, the bottles are supplied in sealed condition, partially filled with liquid growth medium. Sealing is effected by an aluminium crimped seal or threaded cap having a central aperture closed by a rubber septum, typically a septum of chlor-butyl rubber.

In use, a sample, such as a sample of blood or other body fluid, is injected directly into the culture bottle through the septum by use of a syringe, and the septum seals itself when the needle of the injecting syringe is withdrawn from the bottle.

Under normal circumstances there will always be a volume of gas in the headspace above the liquid in the bottle which has received the injected sample. Changes in internal pressure can result from temperature changes, e.g. warming of the bottle to normal culturing conditions, which typically takes place at about 37 °C. The presence of microorganisms is indicated by production or absorption of gas as the species grow, leading to a change in pressure in the bottle headspace which may be monitored. Patent Specification No. WO 94/19698 discloses a monitoring method in which internal pressure changes are detected by measuring deflections of the rubber septum.

It is also known, however, for example from European Patent Specification No. 0592728 Al, to monitor the pressure in the bottle headspace by means of a bottle top incorporating a pressure transducer. The bottle top includes a dependent hollow needle which punctures the rubber septum when the bottle top is attached to the bottle, thereby placing the bottle headspace in communication with the pressure transducer in the bottle top. Monitoring then proceeds with the aid of remote electronics, which compares measured absolute pressure values with known standard absolute values.

It is a primary aim of the present invention to provide an improved sealing device for a fluid container, for example a culture bottle, which facilitates the establishment of communication between the bottle interior and an external monitoring device, especially a measurement device fitted to the top of the bottle.

The Invention

According to one aspect of the present invention, there is provided a sealing device for a fluid container, said device including a rubber septum and a puncturing device operable to puncture the septum.

In another aspect, the present invention provides a sealed container unit comprising a fluid-containing container and the sealing device as aforesaid sealing the top of the container.

Puncturing of the septum enables communication to be established with the container interior. To diis end, the puncturing device is preferably a needle, conveniently a hollow needle, which advantageously places the interior of the container in communication with a measurement device which is connectable to the sealing device.

Preferably, the needle is arranged in the sealing device automatically to puncture the rubber septum when the measurement device is connected to the sealing device.

The sealing device, in a preferred construction, includes a chimney upstanding from the septum, the puncturing device being housed in the chimney.

The said chimney is preferably adapted at the top to receive a connector of the measuring device above the puncturing device. The chimney may be internally splined at the top to receive a ridged connector of the measurement device in a predetermined orientation. This is one of several ways in which it can be ensured that the measurement device makes a pneumatic seal with the sealing device.

While operation of the puncturing device could be a separate operation, preferably the fitting of the measurement device automatically depresses the puncturing device to cause the needle to puncture the septum.

The septum preferably has an area of weakening below the puncturing device, whilst over its major area at least being sufficiently thick to remain substantially undeformed by pressure variations within the container.

It will be appreciated that the aforedescribed sealing device and container unit are especially suitable for application to the aforedescribed field of testing for presence of microorganisms in a sample of blood or other body fluid, in which instance the container takes the form of a liquid culture bottle partially filled with me culture.

To this end, the needle is preferably adapted to place the measurement device in pressure communication with a headspace in the culture bottle above the liquid therein.

More generally, therefore, in accordance with another aspect of the invention, there is provided a method of monitoring the contents of a container unit as previously described, wherein a measurement device is attached to the sealing device to cause the puncturing device to puncmre the septum and thereby place the measurement device in communication with the interior of the container. Especially when dealing with liquid culture bottles, it is important that said communication is established without at any time exposing the contents of the container to atmosphere, and this is facilitated by use of the sealing device in which the puncturing device is incorporated, as distinct from being a separate device or forming part of a monitoring device.

Description of Embodiment

The invention will be further described, by way of illustration, with reference to the accompanying drawing, the single figure of which shows stages in the fitting of a sensing unit to a sealed culture bottle.

Detailed Description of the Drawing

The left hand side of the drawing shows a culmre bottle 10 which, as supplied, has a chlor-butyl rubber sepmm 12 which is thicker than that conventionally used. This sepmm is held in place by a crimped aluminium seal 14, but a screw-on seal could be used instead. The relatively thick sepmm is susceptible to a minimum extent to changes in barometric pressure, and likewise to pressure variations within the bottle headspace 16.

The preferred construction of rubber sepmm illustrated is integrally moulded, with an upstanding tube or chimney 18 protruding through the sepmm. at the bottom of which, below the principal plane of the major pan of the septum, the sepmm has an area of reduced thickness 32.

Within the chimney 18 is located a sepmm puncturing device 20, shown in its rest position for the bottle 10 on the left hand side of the drawing. The present invention, in its broadest aspect, resides in the rubber sepmm or sealing device thus far described.

In another aspect, the invention relates to the container unit formed by the bottle 10 fitted with the sepmm incorporating the puncturing device. Thus, in practice, the bottle is supplied wim the chimneyed sepmm 12 containing puncturing device 20 in place, protected at the top of the chimney by a removable cover plug 22.

The container unit in accordance with the invention is especially suited to receive an intelligent bottle top 24 shown, prior to fitting, above the centre bottle 10 in the drawing. This intelligent bottle top is the subject of our copending European Patent Application No. 96304359.1. The cover plug 22 at the top of the chimney 18 of the bottle 10 has been removed ready for fitting of the bottle top 24, which takes the form of a measurement device which is battery powered, and comprises a miniature pressure transducer, an analogue to digital converter, a processor storing a data- interpretation algoritiim, and a display device 26. These are contained within a housing which has a peripherally ridged underside boss 28 which can be sealingly engaged in the chimney 18 of the sepmm of me bottle. The chimney 18 and boss 28 may be internally splined at the top to ensure that the measurement device is located in a predetermined orientation. This arrangement of chimney and boss fitting closely therein ensures a very effective pneumatic seal.

Referring again to the drawing, the right hand bottle 10 is shown with the measurement device 24 in fitted condition. It can be seen that, when the boss 28 on the bottom of the housing is inserted into the top of me chimney 18, the puncturing device 20, which includes a hollow needle 30, penetrates the sepmm 12 at the area of reduced thickness 32 aligned with the needle at the bottom of the chimney, thereby to open pressure communication through the needle to the pressure transducer in the measurement device. Communication is established via a sterility barrier 34 forming pan of the puncturing device 20, not only to avoid contamination of the measurement device and ensure that it is re-usable, but also to ensure riiat the bottle contents are not contaminated from the pressure transducer. It is important that the sepmm 18 reseals around the needle 30 after puncturing, and to ensure this me sepmm is preferably made of chlor-butyl rubber, as previously mentioned.

While particularly described with reference to culture bottles, the invention is not limited to this application, but may be employed in many odier fields, such for example as biological oxygen absorption in water. Morover, the measurement means which communicates with the interior of the fluid containing container after the sepmm has been punctured may take various forms, as necessary to monitor any one or more chosen parameters, not necessarily pressure, associated with the contents of the container. It is therefore not essential for the attachment of the measurement means automatically to cause the sepmm to be punctured. A modified sealing device may be provided for manual operation of the puncturing device, and subsequent attachment of the measuring means.

Claims

1. A sealed container unit comprising a fluid-containing container and a sealing device sealing the top of the container, wherein said sealing device includes a rubber sepmm and a puncturing device operable to puncmre the sepmm.

2. A container unit according to claim 1, wherein the puncturing device is a needle.

3. A container unit according to claim 2, wherein the needle is a hollow needle for placing the interior of the container in communication with a measurement device connectable to the sealing device.

4. A container unit according to claim 3, in which the needle is arranged in the sealing device automatically to puncmre the rubber sepmm when the measurement device is connected to the sealing device.

5. A container unit according to any one of the preceding claims, wherein the sealing device includes a chimney upstanding from the sepmm, me puncturing device being housed in the chimney.

6. A container unit according to claim 5, wherein the chimney is adapted at the top to receive a connector of the measuring device above the puncturing device.

7. A container unit according to claim 6, wherein the chimney is internally splined at die top to receive a ridged connector of the measurement device in a predetermined orientation.

8. A container unit according to claim 4, in which fitting the measurement device automatically depresses the puncturing device to cause the needle to puncmre the sepmm.

9. A container unit according to any one of me preceding claims, wherein the sepmm has an area of weakening below the puncturing device.

10. A container unit according to any one of the preceding claims, wherein the sepmm is sufficiently thick to remain substantially undeformed by pressure variations within the container.

11. A container unit according to any one of the preceding claims, wherein the container is a liquid culture bottle partially filled with the culture.

12. A container unit according to claim 11 when appendant to claim 3, wherein the needle is adapted to place me measurement device in pressure communication with a headspace in me culture bottle above the liquid therein.

13. A container unit according to any one of the preceding claims, wherein the puncmring device includes a sterility barrier.

14. A method of monitoring the contents of a sealed container unit according to any one of me preceding claims, wherein a measurement device is attached to the sealing device to cause the puncmring device to puncmre the septum and thereby place the measurement device in communication with the interior of the container.

15. A method according to claim 14, according to which said communication is established without at any time exposing the contents of the container to atmosphere.