Connector

A connector is provided for selectively coupling one or more lines or wires (19′, 19″) to a receiving and/or transporting device (27). The connector comprises at least one line or wire receiving ferrule (7) having a plurality of line and/or wire receiving holes (17′-17″) each capable of receiving one of said one or more lines or wires (19′, 19″), wherein said connector further comprises a body (3) for receiving said ferrule (7) and clamping means (9, 11) for exerting a force on said ferrule (7) in order to simultaneously exert a line or wire clamping force on all said line and/or wire receiving holes (17′-17″). In this way all the fluid lines or wires can be clamped at the same time.

CROSS REFERENCE TO RELATED APPLICATION

This application is a filing under 35 U.S.C. §371 and claims priority to international patent application number PCT/EP02/11531 filed Oct. 15, 2002, published on May 1, 2003 as WO03/036103, and to foreign application number 0125074.5 filed in Great Britain on Oct. 19, 2001, the entire disclosures of which are hereby incorporated by reference.

1. Field of the Invention

The present invention relates to devices of the type mentioned in the preambles of the independent claims.

Much effort is being expended on producing microfluidic devices for analysing small volumes of liquids. Many companies are producing so-called “labs on a chip”. Such a lab on a chip typically comprises a disk or block (a “chip”) made of an inert transparent material, e.g. a plastic, in which microchannels are formed. Samples of substances to be analysed can be inputted to these microchannels and these microchannels lead to chambers where the samples can be reacted with reagents. The results of the reactions may be observed through the transparent disc or block walls and/or the products of the reactions may be output from the chip for further processing or analysis. Thus there is a need to connect the chips to input and output interfaces. This poses many problems as the microchannels are small, typically a few micrometers in width or diameter, and it can be difficult to align input devices with them. Additionally some of the input devices, e.g. liquid chromatographs, work at high pressures and it has proven to be difficult to prevent leakage when using such input devices. This is particularly true when very narrow diameter silica tubes are used as the pressure drop over them is very high and therefore pressures are used which are tens or hundreds of times greater than atmospheric pressure.

Similar problems occur when connecting pneumatic systems and hydraulic systems. Additionally, it is often difficult to satisfactorily connect electrical wires, optical cables and the like to devices such as fluidic chips.

SUMMARY OF THE INVENTION

According to the present invention, at least some of the problems with the prior art are solved by means of a connector device having the features present in the characterising part of claim1and a connector ferrule having the features mentioned in the characterising part of claim7. Further improvements are obtained by devices having the features mentioned in the dependent claims.

DETAILED DESCRIPTION OF EMBODIMENTS ILLUSTRATING THE INVENTION

In this example of an embodiment of the invention, it will be illustrated how fluid transporting capillaries can be connected to a fluid receiving and transporting chip. It should be noted that the present invention is not restricted to use such capillaries and chips but may also be used for connecting electrical wires to a component or other wires, fibre optic wires to a component or other wires, hydraulic lines to a component or other lines, etc.

A connector1in accordance with the present invention is shown in section inFIG. 1and a view from above of the connector ofFIG. 1is shown inFIG. 2.

Connector1has a cylindrical connector body3with an tapered axial through hole5. Body3is made of any suitable material, such as stainless steel, which is able to withstand the forces exerted during assembly and operation of the connector. A connector ferrule7in the shape of a truncated cone and adapted to fit into through hole5with its narrow end7A extending through the narrow end of through hole5is positioned in through hole5. Ferrule7is designed to be less rigid than the body3, and preferably is made of a machinable plastic, for example PEEK (essentially polyetheretherketone) or the like. Ferrule7is retained in connector body3by a ferrule presser plate9which can be attached by attaching means such as bolts or screws11onto connector body3at the end where the though hole5is widest. Ferrule presser plate9has a pressure surface9A which faces towards, and is intended to fit and press against, the end surface8of the widest end7B of connector ferrule7. The force that presses connector ferrule7into through hole5can be adjusted by adjusting the force which the attaching means11exerts on pressure plate9. Ferrule presser plate9is designed to be more rigid than the connector ferrule7. As ferrule presser plate9is bolted towards hole5, its pressure surface9A comes into contact with the widest end surface7B of connector ferrule7and consequently it forces the tapered surface7C of connector ferrule7against the tapered portion5B of through hole5. Connector ferrule7can thereby be compressed between the tapered portion5B of through hole5and ferrule presser9. As both body3and presser plate9are both more rigid than ferrule7then ferrule7deforms first under the compression forces.

Ferrule presser plate9has a central opening13, and ferrule7has a cylindrical cavity15at its widest end. This cavity15is substantially concentric with the central opening13in ferrule presser plate9. The lower end of cavity15contains a plurality of capillary receiving through holes17′,17″-17N(only two of which are shown inFIG. 1for the sake of clarity) that extend from the base of cavity15to the bottom surface of ferrule7. Capillary receiving through holes17′,17″-17Nare preferably equidistantly spaced apart and arranged in a circle centred on the centreline of ferrule7, or arranged in another regular pattern, so that when ferrule7is compressed then the forces that act on each capillary receiving through holes17′,17″-17Nare similar. The upper ends (i.e. the ends which open out into the cavity15)17A of capillary receiving through holes17′,17″-17Nare tapered so that they become narrower towards the bottom and at approximately half way along their depth they become cylindrical, so that the lower ends17B of capillary receiving through holes17are cylindrical. The diameter of at least a portion of the lower ends17B of capillary receiving through holes17when uncompressed is substantially the same as, or greater than, the diameter of the fluid tubing such as capillaries19′,19″-19Mwith which the connector1is intended to be used, e.g. 0.36 mm if silica capillaries are used or 0.18 mm if micro-silica capillaries are used, so that the capillaries can be inserted a distance into the lower ends17B. As the clamping of the capillaries by the ferrule takes place in this portion of the lower ends17B, preferably the diameter of this portion should be sufficiently large so that the capillaries can be easily inserted into this portion and should be sufficiently small such that even when the ferrule is unclamped the capillaries are lightly held in the ferrule in order to prevent them being accidentally detached during handling of the ferrule. It is possible to provide a capillary receiving though hole with a stepped and/or tapering diameter with an upper portion with a diameter of about 0.36 mm and which is stepped and/or tapered down to a diameter of about 0.18 mm so that the a ferrule could be used with both 0.36 mm diameter capillaries and 0.18 mm diameter micro-capillaries. Optionally, the bottom of each capillary receiving through hole17may be provided with a ledge17C which prevents the passage of capillaries. The height of the ledge should be chosen to prevent the capillaries19′,19″ from being inserted too far into through holes17′,17″-17Nand projecting out of the narrow, bottom surface10of ferrule7.

In order to make the connector as small as possible, the distance between centres of the capillary receiving through holes17′,17″-17Ncan be small, for example of the order of 0.5 mm if silica capillaries with an outside diameter of 0.36 mm are used and 0.25 mm if micro-silica capillaries (outside diameter 0.18 mm) are used. The tapered upper ends17A of capillary through holes17act as funnels and make it easier to thread the capillaries19′,19″ in the capillary receiving through holes17. As ferrule presser plate9pushes connector ferrule7down into through hole5, connector ferrule7is compressed between ferrule presser9and the tapered portion5B of through hole5. As ferrule7is less rigid than body3which has the tapered portion5B of through hole5formed in it, the tapered lower end7B of connector ferrule7deforms. One of the few directions in which the material can deform is towards the inside of the capillary receiving through holes17′,17″-17N. This causes a radial force towards the centre of each capillary receiving through hole17′,17″-17N. This results in a clamping force on the capillaries19′,19″-19Mintroduced into the through holes17′,17″-17N. This clamping force can be increased by clamping ferrule presser9closer to through hole5and can easily be enough to form a fluid tight seal which can resist over 1000 bar—a pressure which has been difficult to achieve in prior art connectors for use in high pressure liquid chromatography, mass spectrometry and electrophoresis and the like. When the capillary receiving holes are arranged symmetrically, for example as shown inFIG. 2, the clamping force on each capillary is substantially equal.

Connector body3is provided with slots23in its side walls25in order to allow a fluid receiving and/or transporting device such as a chip27to be placed in contact with the end surface10of the narrow end7A of connector ferrule7. Chip27is provided with microchannels29′,29″ which are connected to openings31′,31″-31Min the top surface27A of chip27. In a preferred embodiment of the present invention the number of openings31′,31″-31Mpreferably is equal to the number of capillary receiving through holes17′,17″-17Nand the openings31′,31′-31Mare positioned so that they can all be simultaneously aligned with capillary receiving through holes. It is also conceivable to have more openings than capillaries and vice versa. Preferably connector ferrule7and chip27are provided with complementing guide pins and holes (not shown), or co-operating guide surfaces in order to facilitate and ensure correct alignment. Alternatively, the through holes17may be made without ledges17C and the end of at least one capillaries allowed to project out of the bottom of at least one through hole in order to act as a guide pin.

In order to provide a sealing force between the capillary receiving through holes17′,17″-17Nand openings31′-31M, chip27is supported on a movable support plate35. Support plate35is positioned on the opposite side of the chip to the connector ferule7and preferably the face of support plate35in contact with the chip has a shape and dimensions similar which are adapted the face of the ferrule7in contact with the opposite face of the chip and is positioned directly underneath the ferrule such that no damaging stress concentrations are formed in the chip when it is clamped between the ferrule7and support plate35. The support plate35is provided with compression force producing means such as a spring37positioned between support plate35and a movable compression plate39, and means such as bolts41for moving the compression plate39towards or away from support plate35. Bolts41can be used to adjust the force that support plate exerts on chip27—moving compression plate39closer to chip27increases the force between chip27and connector ferrule7and vice versa. The spring37allows the force exerted by the bolts41to be finely controlled. The slots23are deeper than the thickness of a chip27so that when ferrule7and support plate are clamping a chip27in its working position then chip27is not in contact with any part of body3. In other words there is a gap51between the upper surface of chip27and the upper interior surfaces of slots23and a gap53between the bottom surface of chip27and the lower interior surfaces of slots23. This means that chip27is supported by ferrule7and support plate35which maximises the clamping forces to where they are needed and prevents the occurrence of asymmetric clamping forces which could otherwise occur if chip27came into contact with the side walls25. Support plate35and compression plate39could be made of a transparent material in order to facilitate alignment of the components and to allow easy visual checking of the alignment.

Ferrule7is preferably provided with means such as a key-way and key or projections adapted to fit in corresponding depressions in connector body3in order to for preventing it from rotating once it has been placed in body3, in order to prevent capillaries from becoming twisted and to ensure that the capillaries are connected to the intended opening on the chip when in use. This can be achieved in many different ways, for example by making it asymmetric, e.g. by providing a projecting stub (not shown), and by providing body3with a complementary recess (not shown), so that ferrule7can be held fixed against rotation with respect to body3.

A connector in accordance with the present invention can be assembled in the following way: the operator threads the required number of capillaries19′-19Mthrough the central opening13of ferrule presser plate9. A first capillary19′ is then introduced into cavity15of connector ferrule7, fed into the tapered upper end17A of a first through hole17′ and pushed approximately all the way into the lower end17B of the through hole17′ until it reaches the ledge17C near the bottom of the through hole17′. This is repeated for a second capillary and a second through hole, until all the capillaries19′-19Mhave been mounted in their respective through holes17′-17N. The connector ferrule7is then positioned in the through hole5with tapered bottom end7B located in the tapered lower end5B of through hole5. The ferrule presser plate9is positioned on top of connector ferrule7and bolts11tightened towards body3so that ferrule7is pressed into the tapered bottom end5B of through hole5so that it deforms enough such that the through holes17′,17″-17Nbecome narrower and grip the capillaries19′-19M. A chip27can then be inserted through slots23and aligned with its openings31′,31″-31Meach directly aligned with one of the through holes17′,17″-17N. Bolts41can then be tightened until chip27is in contact with the narrow end surface10of ferrule7. Further tightening of bolts11and/or41will increase the sealing force between narrow end surface10and the chip27.

It is conceivable to provide a connector in accordance with the present invention in which the ferrule presser plate is provided with a plurality of axial guide holes for capillaries instead of a central cavity. Each guide hole would have an outlet at the bottom of the ferrule presser plate and the outlet would be arranged to align with capillary receiving through holes in the connector ferrule. The connector ferrule and ferrule presser plate could be provide with co-operating alignment means such as a projection on one of these components which fits into a recess on the other component in order to ensure correct alignment

While the embodiment of the present invention illustrated in the figures depicts a connector in which the connector ferrule and the chip have flat mating surfaces, it is of course possible to use other surface shapes which can seal against each other. For example, a connector ferrule can have a concave surface and a chip a matching convex surface (or a surface which becomes convex when compressed during use), or vice versa.

Additionally, it is also possible to use a plurality of ferrules in one connector body in order to connect fluid lines to a plurality of chips simultaneously, or to connect fluid lines to a plurality of regions on a single chip simultaneously.

Additionally, it may be advantageous to provide the connector ferrule with a narrow end surface which, when unloaded, is concave from its centre to the radial distance corresponding to the part of the through holes17′,17″-17N which is nearest the centre in order to relieve stress at the interface between the chip and the connector ferrule when in use.

Furthermore, it is not necessary that the through hole in the connector body and the ferrule have matching tapered surfaces—it is conceivable to use a cylindrical ferrule7′ in a tapered hole5′ as shown schematically inFIG. 3a). It is also conceivable to use a ferrule7″ with a quadratic cross-section in a tapered quadratic hole5″ as shown schematically inFIG. 3b). With the add of the principle illustrated by the above examples, other complementary shapes for the hole and ferrule which can produce a compression force on the ferrule as it is clamped are readily conceivable to the skilled person.

While the invention ahas been illustrated by am embodiment in which only fluid lines are held in the ferrule, it is conceivable to provide the ferrule with electrical and/or optical wire receiving holes in addition to, or instead of, fluid line receiving holes. This would allow the simultaneous connection of electrical and optical circuits.

The above mentioned example of conceivable embodiments are intended to illustrate the present invention and are not intended to limit the scope of protection claimed by the following claims.