WO2012049480A1

WO2012049480A1 - Component with seal, receiving body, system and method

Info

Publication number: WO2012049480A1
Application number: PCT/GB2011/051945
Authority: WO
Inventors: Andrew Ede; Ross Weir
Original assignee: Sphere Medical Limited
Priority date: 2010-10-13
Filing date: 2011-10-10
Publication date: 2012-04-19
Also published as: GB201017261D0

Abstract

A component (1) is disclosed for engaging with an inner feature of a receiving body (2) in a fluid- tight manner, the component comprising a member comprise an elastomeric seal (3) for engaging with said receiving body; and a structure (5) for increasing the outer diameter of said seal upon engagement of the component with the inner feature. A receiving body for receiving such a component, a system including such a component and a method for forming a fluid- tight connection between such a component and a receiving body are also disclosed.

Description

COMPONENT WITH SEAL, RECEIVING BODY, SYSTEM AND METHOD

FIELD OF THE INVENTION

The present invention relates to a method and apparatus for sealing fluidic connections in medical devices such as patient care systems, for example, for connecting tubes to syringes, wider bore containers or tubes, etcetera.

BACKGROUND OF THE INVENTION

There are many fluidic connection systems commercially available to connect two different fluidic components together in a leak-free manner. One particular type of connection system employs a gasket being compressed between the two components to affect the seal. In order to compress the seal, the connection system will typically employ screw or compression fittings.

Other connection types include push-fit connectors or adaptors. Push fit connectors can typically not be used in applications where the fluid path is pressurised with respect to the environment. In addition they suffer from large dead volumes.

Yet another connector type which is widely used is Luer connectors. These connectors also suffer from relatively large dead volumes.

In addition, there are a range of custom connectors used in the medical field which are typically expensive.

The seal may either be permanently deformed and will have to be replaced when the connection is opened and then resealed. Alternatively, it may be elastically deformed so that it can be re-used. An example of a re-usable seal is an elastomeric o-ring.

In many scientific instruments, for example, those targeted at the analysis of liquid samples, there is a requirement to remove or replace certain components as part of the analysis process. For example, in instruments employed to analyse blood samples with respect to the content of one or more analytes, there are typically disposable components which are replaced after the analysis of one sample (or a small number of samples). In these instruments, there is therefore a need to provide an easy-to-use and reliable connection system to these disposable components.

This is in particular the case in apparatus requiring sample preparation, using, for example, solid-phase extraction (SPE). In such apparatus, the sample or a derivative thereof is passed through a solid phase extraction cartridge to remove substances in the sample which may interfere with the analysis process or to enrich the analyte(s) of interest in the eluent from the cartridge. A solid phase cartridge typically consists of a syringe body which contains an SPE medium, typically in the form of a powder, frit or both. These cartridges are typically single-use components which are replaced after each sample analysis. The cartridge is part of the fluidic circuit of the apparatus and therefore has connections to other fluidic components in this fluidic circuit. Many of these connections employ elastomeric seals which are compressed between the two components to be connected together.

In many cases there is a requirement to connect together components of different diameter. One widely used prior art approach is illustrated in FIG. 1 . It employs an o-ring 3 located in a groove on the outer wall of the smaller component 1 . When component 1 is pushed into component 2 and then held in place (fixing mechanism not shown in this diagram), the o-ring 3 is deformed and provides a seal between the two components. When component 2 needs to be replaced, the seal can be broken by pulling component 1 out of component 2. Following the replacement of component 2 with an equivalent component, the seal can be reformed by pushing component 1 into the equivalent component and again compressing the o-ring 3 to form a seal between the two components. This approach is widely used for connection to SPE cartridges, with component 2 representing the SPE cartridge.

This particular mechanism relies on the o-ring 3 maintaining its elasticity and not being damaged when being pulled out and pushed back into replacement components. There is, however, a problem when the fluid being passed through the fluidic system contains a solvent, for example acetonitrile, which may, for example, either react with the o-ring material, remove any lubricating material from the seal or the inside wall of component 2 or increase the friction between the o-ring 3 and component 2, or when the inside wall of the component 2 damages the o-ring, e.g. because the inside wall of component 2 is rough. In these cases, when replacing component 2, the o-ring 3 can be damaged when component 1 is pulled out of component 2. When reforming the seal after replacing component 2, a leak can result due to the damage caused to the o-ring 3.

Due to the fluid pressures used in a solid-phase extraction system, the fit between components 1 and 2 in the assembled state needs to be tight in order to compress the o-ring 3 sufficiently to prevent a fluid leak. However, this tight fit increases the probability of damaging the o-ring 3 when exchanging the solid-phase cartridge. In addition, the height of the sorbent bed in the solid-phase extraction cartridge can vary and the fluid connection system needs to be able to accommodate such changes in order to avoid over-compression of the sorbent bed or large dead volumes. SUMMARY OF THE INVENTION

The present invention seeks to provide a fluid connection system for use in the medical device field which enables the connection to be broken and reformed while avoiding the issues outlined above. In accordance with an aspect of the present invention, there is provided a component for engaging with an inner feature of a receiving body in a fluid-tight manner, the component comprising a member comprising an elastomeric seal for engaging with said receiving body; and a rigid structure for increasing the outer diameter of said seal upon compression of the component between the inner feature and the structure.

In an embodiment, the member comprises a plunger and the rigid structure comprises a body having an edge portion, wherein the plunger has a sliding portion mounted in the body and an outer portion outside the body and facing said edge portion, said outer portion carrying said seal, wherein the diameter of the outer portion including said seal is larger than the inner diameter of the body, and wherein said edge portion is arranged to increase said outer diameter by compression of said seal between the edge portion and the inner feature.

In an embodiment, the outer portion comprises a recess, said elastomeric seal being fitted in said recess, and an end portion bordering said recess, wherein the diameter of the recess including the elastomeric seal and the diameter of the end portion are both larger than the inner diameter of the outer body.

In another embodiment, the member comprises a deformable end portion, said deformable end portion comprising the elastomeric seal, and wherein the structure is a rigid portion of said member in contact with the deformable end portion for compressing the deformable end portion upon engagement of the deformable end portion with the inner feature.

Advantageously, the elastomeric seal may be mounted on the deformable end portion.

In an embodiment, the deformable end portion acts as the elastomeric seal. The deformable end portion may be made of a material selected from the group of materials comprising rubber, silicone and deformable plastics.

The deformable end portion may comprise a first section and a second section in intimate contact with each other, said sections being separated from each other upon compression of the component between the inner feature and the structure.

In a particularly advantageous embodiment, the elastomeric seal is a rubber O- ring.

In another embodiment, the maximum outer diameter of the component in an unengaged state is at smaller than the relevant inner diameter of the receiving body such that the component may be released from the receiving body in a substantially frictionless manner.

The component may be a connector of a solid phase extraction system.

In accordance with another aspect of the present invention, there is provided an array of components according to any of claims 1 -1 1 , wherein each of said components is arranged to engage with an inner feature of a separate receiving body in a fluid-tight manner.

In accordance with yet another aspect of the present invention, there is provided a receiving body for engaging with a component of any of claims 1 -1 1 , wherein the receiving body comprises an inner volume for receiving the component, said inner volume comprising an upper section and a lower section comprising the inner feature.

In an embodiment, the inner feature is a reduced diameter of the lower section compared to the upper section, said reduced diameter being smaller than the uncompressed maximum outer diameter of the end portion of the component facing the inner feature.

In another embodiment, the inner feature is a member extending across the inner volume in a direction perpendicular to the insertion direction of the component in the inner volume.

The inner feature may comprise a sorbent bed in the receiving body.

In a particularly suitable embodiment, the receiving body is a solid phase exchange cartridge.

In accordance with yet another aspect of the present invention, there is provided a system comprising the component of any of claims 1 -1 1 and a receiving body for engaging with the component in a fluid-tight manner. The receiving body may be a receiving body according to any of claims 13-17. The system may be a solid phase extraction system, in which case said component is a connector of said solid phase extraction system and the receiving body is a disposable solid phase extraction cartridge.

In accordance with yet another aspect of the present invention, there is provided a method of forming a fluid-tight connection between a component comprising a member comprising an elastomeric seal for engaging with said receiving body and a rigid structure for increasing the outer diameter of said seal, and a receiving body receiving comprising an inner volume for receiving the component, said inner volume comprising an upper section and a lower section comprising the inner feature, the method comprising inserting the member into said receiving body such that an end portion of the member comprising the elastomeric seal is compressed between said structure and the inner feature, said compression causing the diameter of the elastomeric seal to increase such that said seal forms a fluid-tight connection between the component and the receiving body.

In an embodiment, the method further comprises reducing the diameter of the elastomeric seal by removing the contact of at least one of the rigid structure and the inner feature with the elastomeric seal; and subsequently removing the component from the receiving body.

Advantageously, the fluid-tight connection is formed between a connector of a solid phase extraction system comprising the component and a disposable solid phase extraction cartridge comprising the receiving body.

BRIEF DESCRIPTION OF THE EMBODIMENTS

Embodiments of the invention are described in more detail and by way of non- limiting examples with reference to the accompanying drawings, wherein:

Fig. 1 is an illustration of a prior art o-ring based connection system in the unassembled and assembled state;

FIG. 2 schematically depicts a preferred embodiment of a connection system of the present invention;

FIG. 3 schematically depicts an embodiment of a component of the system of

FIG. 2;

FIG. 4 schematically depicts a cross-section of the component of FIG. 3;

FIG. 5 schematically depicts an alternative embodiment of a connection system of the present invention; FIG. 6 schematically depicts a yet another embodiment of a connection system of the present invention; and

FIG.7 schematically depicts an embodiment of a connection system of the present invention comprising an array of fluid connections.

DETAILED DESCRIPTION OF THE DRAWINGS

It should be understood that the Figures are merely schematic and are not drawn to scale. It should also be understood that the same reference numerals are used throughout the Figures to indicate the same or similar parts.

The purpose of this invention is to provide a sealing mechanism which avoids the issues outlined above and, in particular, reduces the need to replace the seal every time component 2 as shown in FIG. 1 is exchanged.

The invention is based on the observation that the act of pulling component 1 out of component 2 is likely to damage the seal due to the tight fit between the components. For example, if the friction between the seal and the inside wall of component 2 is too large or if the inside wall of component 2 is rough, the seal is highly likely to be damaged in this process.

The invention therefore provides a very easy and straightforward mechanism to extract component 1 from component 2 without damaging the seal. This mechanism is designed to be reliable and user-friendly.

The invention uses a deformable structure integrated in component 1 which can result in a change of the inner and outer diameter of the elastomeric seal, e.g. o- ring 3. In the not assembled state, the deformable structure is in a state where there is a loose fit between the elastomeric seal and component 2. In particular, in one example of the invention, the outer diameter of the seal mounted to the structure of component 1 is smaller than the inner diameter of component 2 when in the not assembled state. As component 1 engages with component 2 or material stored in component 2, the deformable structure is deformed and increases the outer diameter of the seal. This action pushes out the seal and presses it into the inner wall of component 2, forming a leak-tight connection.

FIG. 2 shows a preferred embodiment of the invention. In this preferred embodiment component 1 consists of an inner plunger 4, an outer shell 5 and a compliant member 6. The elastomeric seal 3, for example in the form of a rubber o- ring, is mounted on the inner plunger 4. Component 1 is constructed in such a way that the inner plunger 4 is free to move with respect to the outer shell 5. In the not assembled state (a) the outer diameter of the o-ring 3 is either a loose fit or smaller than the inner diameter of component 2. The compliant member 6 ensures that the o- ring 3 is not further compressed in this state.

As component 1 is moved downwards, as shown in (b), by a force acting on the outer shell 5 and component 1 engages with a feature 8 in component 2 or material stored in component 2 illustrated by the shaded area 8 in FIG. 2, the inner plunger 4 moves upwards with respect to the outer shell 5, compressing the compliant member 6 and also the o-ring 3, as shown in (c). This action in turn increases the outer diameter of the o-ring 3 and presses it into the inner wall of component 2, forming a leak-tight connection. Component 1 and component 2 are then held in place by means of any suitable mechanism (not shown).

When component 2 has to be exchanged, component 1 is released with respect to component 2. The compliant member 6 ensures that the inner plunger 4 moves with respect to the outer shell 5 in such a way as to reduce the compression of the o-ring 3 which reduces its outer diameter. Component 1 can then easily moved with respect to component 2 without damaging the o-ring 3 as the o-ring 3 is no longer a tight fit to component 2.

FIG. 3 shows a computer-aided design (CAD) illustration of component 1 in a preferred embodiment of the invention. FIG. 4 shows a cross-section through the component 1 comprising an outer shell 5, an upper part 4a of the inner plunger 4, a lower part 4b of the inner plunger 4, the elastomeric seal 3, e.g. o-ring 3 and a seal 7 between the upper inner plunger 4a and the lower inner plunger 4b.

It is noted that for convenience, the inner plunger 4 in this embodiment is made up out of three separate parts; the upper inner plunger 4a, the lower inner plunger 4b and the seal 7 between the upper inner plunger 4a and the lower inner plunger 4b by way of non-limiting example only; the inner plunger 4 may take any suitable shape, e.g. a one-piece shape.

Another example embodiment of the invention is shown in FIG. 5, which uses a deformable structure 9 integrated at the end of component 1 which can increase in diameter when component 1 and 2 are assembled together.. The o-ring 3 or other suitable elastomeric seal is mounted to this structure 9. The outer diameter of the o- ring 3 is either smaller than the inside diameter of component 2 or is a loose fit to the inside of component 2. Due to this tolerancing, component 1 can slide easily into component 2, as shown in (b). When component 1 comes into contact with the material 8 stored in component 2, e.g. the solid-phase extraction material or frit in the case of component 2 being a SPE cartridge, the deformable structure 9 is compressed and increases in diameter, as shown in (c). This diameter increase pushes (deforms) the o-ring 3 against the inside wall of component 2 and causes a seal to be formed. Component 1 and component 2 can then be held in place relative to each other during use by means of any suitable fixing mechanism (not shown).

When component 2 has to be exchanged, component 1 is released with respect to component 2. This reduces the compression of the deformable structure 9 which, in turn reduces the diameter of the deformable structure 9 and therefore the compression of the o-ring 3. Component 1 can then easily moved with respect to component 2 without damaging the o-ring 3 as the o-ring 3 is no longer a tight fit to component 2.

In another example embodiment of the invention, as shown in FIG. 6, the compression of the deformable structure is formed by a reduction in diameter of component 2, for example a ledge or a step 10 in component 2. The deformable structure 9 compresses and expands in diameter when it is pressed against the ledge or step 10 in component 2.

In another example embodiment of the invention (not shown), component 1 forms the deformable structure.

In yet another example embodiment of the invention (not shown), the seal between component 1 and 2 is formed by the deformable structure 9 itself, i.e. the elastomeric seal 3 is omitted.

While the invention has been described in terms of making a leak-tight fluid connection between a single component 1 and a single component 2, it is emphasized that the invention can also be applied to making several of such connections in parallel.

In one particular embodiment of the invention, as shown in FIG. 7, a multitude of connector components 1 as described above are assembled on a common carrier 1 1 in either a one-dimensional or two-dimensional array. Similarly, a multitude of components 2 are mounted on a second carrier 12 in such a manner that there is for each component 2 to be connected there is a component 1 . When the two carriers are moved towards each other, i.e., from disengaged position (a) to engaged position (b), the component 1 parts and the component 2 parts engage with each other to form a multitude of leak-tight seals.

In yet another embodiment of the invention (not shown) there is a multitude of inner plungers of component 1 which all share a common outer shell. In yet another embodiment of the invention (not shown) all the components 2 may share a common body. In one particular embodiment, the component 2 array consists of a number of openings machined into a common block of material.

The seal 3 can be realised in a wide number of materials known to those skilled in the art of fluid connections. Examples include, but are not limited to EPDM (ethylene propylene diene Monomer (M-class) rubber), Nitrile, Silicone, FPM (Fluorinated propylene monomer (elastomer) and Viton.

It should be noted that the above-mentioned embodiments illustrate rather than limit the invention, and that those skilled in the art will be able to design many alternative embodiments without departing from the scope of the appended claims. In the claims, any reference signs placed between parentheses shall not be construed as limiting the claim. The word "comprising" does not exclude the presence of elements or steps other than those listed in a claim. The word "a" or "an" preceding an element does not exclude the presence of a plurality of such elements. The invention can be implemented by means of hardware comprising several distinct elements. In the device claim enumerating several means, several of these means can be embodied by one and the same item of hardware. The mere fact that certain measures are recited in mutually different dependent claims does not indicate that a combination of these measures cannot be used to advantage.

Claims

1 . A component for engaging with an inner feature of a receiving body in a fluid- tight manner, the component comprising:

a member comprising an elastomeric seal for engaging with said receiving body; and

a rigid structure for increasing the outer diameter of said seal upon compression of the component between the inner feature and the structure.

2. The component as claimed in claim 1 , wherein the member comprises a plunger and the rigid structure comprises a body having an edge portion, wherein the plunger has a sliding portion mounted in the body and an outer portion outside the body and facing said edge portion, said outer portion carrying said seal, wherein the diameter of the outer portion including said seal is larger than the inner diameter of the body, and wherein said edge portion is arranged to increase said outer diameter by compression of said seal between the edge portion and the inner feature.

3. The component of claim 2, wherein the outer portion comprises a recess, said elastomeric seal being fitted in said recess, and an end portion bordering said recess, wherein the diameter of the recess including the elastomeric seal and the diameter of the end portion are both larger than the inner diameter of the outer body.

4. The component of claim 1 , wherein the member comprises a deformable end portion, said deformable end portion comprising the elastomeric seal, and wherein the structure is a rigid portion of said member in contact with the deformable end portion for compressing the deformable end portion upon engagement of the deformable end portion with the inner feature.

5. The component of claim 4, wherein the elastomeric seal is mounted on the deformable end portion.

6. The component of claim 4, wherein the deformable end portion acts as the elastomeric seal.

7. The component of any of claims 4-6, wherein the deformable end portion is made of a material selected from the group of materials comprising rubber, silicone and deformable plastics.

8. The component of any of claims 4-6, wherein the deformable end portion comprises a first section and a second section in intimate contact with each other, said sections being separated from each other upon compression of the component between the inner feature and the structure.

9. The component of any of claims 1 -5, wherein the elastomeric seal is a rubber O-ring.

10. The component of any of claims 1 -9, wherein the maximum outer diameter of the component in an unengaged state is at smaller than the relevant inner diameter of the receiving body such that the component may be released from the receiving body in a substantially frictionless manner.

1 1 . The component of any of claims 1 -10, wherein the component is a connector of a solid phase extraction system.

12. An array of components according to any of claims 1 -1 1 , wherein each of said components is arranged to engage with an inner feature of a separate receiving body in a fluid-tight manner.

13. A receiving body for engaging with a component of any of claims 1 -12, wherein the receiving body comprises an inner volume for receiving the component, said inner volume comprising an upper section and a lower section comprising the inner feature.

14. The receiving body of claim 13, wherein the inner feature is a reduced diameter of the lower section compared to the upper section, said reduced diameter being smaller than the uncompressed maximum outer diameter of the end portion of the component facing the inner feature.

15. The receiving body of claim 13, wherein the inner feature is a member extending across the inner volume in a direction perpendicular to the insertion direction of the component in the inner volume.

16. The receiving body of claim 15, wherein the inner feature comprises a sorbent bed in the receiving body.

17. The receiving body of any of claims 13-16, wherein the receiving body is a solid phase exchange cartridge.

18. A system comprising the component of any of claims 1 -12 and a receiving body for engaging with the component in a fluid-tight manner.

19. The system of claim 18, wherein the receiving body is a receiving body according to any of claims 13-17.

20. The system of claim 18 or 19, wherein the system is a solid phase extraction system, said component is a connector of said solid phase extraction system and the receiving body is a disposable solid phase extraction cartridge.

21 . A method of forming a fluid-tight connection between a component comprising a member comprising an elastomeric seal for engaging with said receiving body and a rigid structure for increasing the outer diameter of said seal, and a receiving body receiving comprising an inner volume for receiving the component, said inner volume comprising an upper section and a lower section comprising the inner feature, the method comprising inserting the member into said receiving body such that an end portion of the member comprising the elastomeric seal is compressed between said structure and the inner feature, said compression causing the diameter of the elastomeric seal to increase such that said seal forms a fluid-tight connection between the component and the receiving body.

22. The method of claim 21 , further comprising:

reducing the diameter of the elastomeric seal by removing the contact of at least one of the rigid structure and the inner feature with the elastomeric seal; and subsequently removing the component from the receiving body.

23. The method of claim 21 or 22, wherein the fluid-tight connection is formed between a connector of a solid phase extraction system comprising the component and a disposable solid phase extraction cartridge comprising the receiving body.