WO2000003225A1

WO2000003225A1 - Device for introducing and/or withdrawing a quantity of liquid into or respectively from a tube

Info

Publication number: WO2000003225A1
Application number: PCT/SE1999/001236
Authority: WO
Inventors: Peter GÅRDHAGEN; Claes Andersson; Magnus Samuelsson; Arne Alm; Åke Jansson
Original assignee: Biosensor Applications Sweden Ab (Publ)
Priority date: 1998-07-08
Filing date: 1999-07-07
Publication date: 2000-01-20
Also published as: AU5076499A; SE9802459D0; SE515031C2; SE9802459L

Abstract

A device for introducing and/or withdrawing a quantity of liquid into or respectively from a tube, preferably a capillary, is described. The device includes a cylinder part (1) with inlet and outlet openings (5, 6) connected to inlet and outlet channels (7, 8) and a displaceable piston part (2) with an axial channel (11) from which extend inlet and outlet channels (9, 10), and a lifter (12). When the piston part (2) is displaced, its inlet and outlet channels (9, 10) are brought into line with the inlet and outlet openings (5, 6) of the cylinder part (1), but during further displacement are closed. During further and larger displacements of the piston part (2), the lifter (12) discharges the quantity of liquid that is trapped in the axial channel (11) into a tube (16) sealed tightly against the free end of the piston (2), and/or during displacement of the piston part (2) in the return direction, the suction action of the lifter (12), causes the existing quantity of liquid in the tube to be drawn into the axial channel (11) and be flushed from the device when the connections with the inlet and outlet openings (5, 6) are reestablished through the displacement of the piston part (2).

Description

Device for introducing and/or withdrawing a quantity of liquid into or respectively from a tube.

The present invention relates to a device for introducing and/or withdrawing a quantity of liquid or fluid into or respectively from a tube, e.g. a capillary, cannula, test tube or similar volume, from and/or back to a preferably flowing liquid. The device is designed so that the respective introduction or withdrawal of the quantity of liquid takes place without the occurrence of air or other gas bubbles. This is particularly advantageous when the tube is a capillary and the quantity of liquid withdrawn includes a component that is to be analysed by a method that is disturbed by bubbles of air in the liquid to be analysed. Background

When developing automated analysis systems where the component to be analysed was present in a condensate in a capillary, problems with leaching of the condensate from the capillary occurred. Manual leaching of the capillary, i.e. introduction and withdrawal in a conventional manner by means of a cannula or pipette device led to spillage of the leaching liquid and the occurrence of air bubbles in the liquid that was to be analysed.

Known devices that would have resolved this problem were not available on the market, which is why something new had to be invented. Description of the invention The device according to the invention can be integrated in a highly automated analysis and detection system, whereby the substance whose presence is to be analysed/detected is found in a condensate in a capillary that can be enclosed by a cold trap. By the aid of the device according to the invention, the substance can then be leached from the capillary with a quantity of a solvent that is introduced into the capillary and withdrawn from the capillary and then transferred as a integrated unit without air bubbles with a flow of the solvent to a vessel suitable for analysing a liquid, e.g. an analytical piezo-electric cell. When the capillary has been leached with solvent, it can be moved from its position and replaced by the next capillary whose contents are to be analysed by means of, for example, a revolver. The device according to the invention can also be used for other purposes, for example, to fill cannules or test tubes, especially when one does not want air and/or skin to come into contact with the liquid used for filling. Examples include filling cannules with pharmaceuticals or test tubes with reagents. The same applies in reverse, i.e. withdrawing a specific quantity of liquid from a tube. For these applications, the device is preferably turned so that the openings of the cannules and the test tubes face upward and the device is above these.

Summary of the invention

The essential details of the device according to the invention for introducing and/or withdrawing a quantity of liquid into or respectively from a tube are a cylinder part with inlet and outlet openings connected to inlet and outlet channels, whereby the inlet channel is provided with a closure device, and a displaceable piston part in the cylinder part with an axial channel running all the way through it, from which extend in essentially radial directions inlet and outlet channels, and a lifter arranged at the cylinder part, whereby the arrangement is such that when the piston part is displaced, its inlet and outlet channels are brought into line with the inlet and outlet openings of the cylinder part, but are closed off during further displacement and interaction with the jacket wall of the cylinder, whereby during a further and larger displacement of the piston part, the lifter, which runs in the axial channel of the piston part, is arranged to discharge the quantity of liquid that is trapped in the axial channel of the piston, due to the closed off inlet and outlet channels, into a tube sealed tightly against the free end of the piston, and/or during displacement of the piston part in the return direction with the arranged tube sealed tightly against this and by the suction action of the lifter, the existing quantity of liquid in the tube, possibly together with substances solubilised and entailed during its presence in the tube, will be drawn into the axial channel of the piston part and be flushed from the device via the outlet channel (8) as an integrated quantity of liquid when the connections with the inlet and outlet openings are re-established through the displacement of the piston part.

In one preferred embodiment of the device according to the invention, the tube is a capillary. The invention will be described in greater detail below with the help of an embodiment that is illustrated in the attached drawings, and an example of an embodiment. Brief description of the drawings

Fig. 1 is an axial section through a schematically shown embodiment of a device according to the invention in its initial position. Fig. 2 shows in the same way the same device with the capillary device connected.

Fig. 3 shows the same device with the capillary device during transfer of fluid or liquid from the cylinder part to the capillary part. Description of a working example

The device includes a cylinder part 1 and a piston part 2. At one end, the cylinder part 1 is provided with a bottom 3 and it has an inlet opening 5 and an outlet opening 6 in its jacket wall 4. These openings are axially displaced from one another where the inlet channel 7 and outlet channel 8 respectively are connected.

In the same way as inlet opening 5 and outlet opening 6, the piston part 2 has two axially displaced inlet and outlet channels 9 and 10, respectively, that extend from the peripheral surface of the piston to a central channel 11 running all the way through it.

A lifter 12 extends from the bottom 3 of the cylinder part 1 and seals tightly in the central channel 11 of the piston part 2 and has a length such that even when the piston part 2 is in its fully raised position, it is still tightly sealed against central channel 11.

In one preferred embodiment, a pressure spring, e.g. foam rubber or one end of a helical spring 13, rests against the bottom 3, and is set up so that it attempts to displace piston part 2 away from the cylinder bottom 3. As is evident from Fig. 2 and 3, the device is intended to interact with a capillary part, the whole of which is designated 14, that is displaceable relative to the device. In the case shown here, the capillary part 14 comprises a cold trap with a heat reservoir 15, the actual capillary 16 and an O-ring seal 17 arranged to interact with the end surface of the piston part. Fig. 2 shows the capillary in its extended position, whereby the outer opening of the capillary 16 is closed by means of a sealing plate 18.

By means of an upward and downward moveable operating device 19, only implied here, set up to act on stop faces 20 arranged on the remote end surface and on either side of the sealing plate 18, the capillary part 14 can be displaced as a whole entity towards the piston part 2 and, against the effect of the spring 13, inwards into the cylinder part 1 as shown in Fig. 3. ^"

In the position shown in Fig. 1 , the device is not docked, which means that there is no capillary unit at the free end of the piston part. In this initial position of a cycle, the central channel 11 and the inlet and outlet channels 9 and 10 are filled with entrapped liquid as these channels 9 and 10 are closed off by the jacket wall 4 of the cylinder part due to the displacement position of piston part 2. Due to the action of spring 13, the piston part 2 is thus somewhat displaced outwards, which means that the inlet and outlet channels 9 and 10, respectively, of the piston part are located beyond the inlet and outlet openings 5 and 6, respectively, of the cylinder part. When the capillary part 14 is docked and pushed inwards in the manner indicated and as shown in Fig. 2, it will displace the piston part 2 inwards into the cylinder part, which means that the inlet and outlet channels 9 and 10 align with the inlet and outlet openings 5 and 6 and that a flow path for liquid is established from the inlet at 5, via the inlet channel 9, the central channel 11 and outlet channel 10 to the outlet 6. As the capillary 16 in part 14 is closed off at the top by the sealing plate 18, the entrapped air prevents liquid passing through the channels of the piston part 2 from being routed towards capillary 16 and filling it up.

When the capillary unit is pressed downwards further against the action of the spring 13 due to the action of the operating device 19, the inlet and outlet channels 9 and 10 will initially be closed off against the cylinder jacket wall, as is shown in Fig. 3; the outlet channel 10 is also closed off against the lifter 12, and at the same time valve 22 in the inlet channel 7 is closed off, in the manner shown, to prevent liquid from it running into the slot 23 between the jacket wall 4 of the cylinder and the capillary part 14.

At the same time as the capillary and piston parts 14 and 2, respectively, are pressed down, the lifter 12 will be displaced even further into the central channel 11, which leads to the liquid that is trapped there being forced up into the capillary 16. The liquid can then leach out substances that may possibly be found there. The leaching liquid can then be subjected to analysis. When the time calculated to be needed has passed, the spring is allowed to move the piston and capillary parts upwards, whereby the liquid in the capillary is withdrawn again up into the central channel 11 of the piston part 2 due to the action of the lifter 12. From there, the withdrawn quantity of liquid is transferred onwards with the help of the liquid that, when the piston part has reached the position according to Fig. 2 and valve 22 has opened, can once again flow through as a well defined part of the flow and without air bubbles out of the device through outlet channel 8 for possible analysis.

Claims

1. Device for introducing and/or withdrawing a quantity of liquid into or respectively from a tube c h a r a c t e r i s e d in that it includes a cylinder part (1) with inlet and outlet openings (5,6) in its jacket wall (4) connected to inlet and outlet channels (7,8) whereby the inlet channel (7) is provided with a closure device (22), and a displaceable piston part

(2) in the cylinder part (1) with an axial channel (11) running all the way through it, from which extend in essentially radial directions inlet and outlet channels (9,10), and a lifter (12) arranged at the cylinder part (1) and running tightly sealed in the axial channel (11), whereby the arrangement is such that when the piston part (2) is displaced, its inlet and outlet channels (9,10) are brought into line with the inlet and outlet openings (5,6) of the cylinder part (1), but are closed during further displacement by interaction with the wall of the cylinder jacket (4), whereby during a further and larger displacement of the piston part (2), the lifter (12), which runs in the axial channel (11) of the piston part (2), is arranged to discharge a quantity of liquid that is trapped in the axial channel (11) of the piston part (2), due to the closed inlet and outlet channels (9,10), into a tube (16) sealed tightly against the free end of the piston (2), which tube (16) interacts with the cylinder part (1) and the piston part (2) and is displaceable with regard to them, and/or during displacement of the piston part (2) in the return direction and with the arranged tube (16) and which is sealed tightly against this and by the suction action of the lifter (12), a quantity of liquid present in the tube (16), possibly together with substances solubilised and entailed during its presence in the tube, will be drawn into the axial channel (11) of the piston part (2) and be flushed from the device via the outlet channel (8) as an integrated quantity of liquid when the connections with the inlet and outlet openings (5,6) are re-established through the displacement of the piston part (2).

2. Device according to claim l c h a r a c t e r i s e d in that the tube (16) is a capillary.

3. Device according to claim l or 2 c h a r a c t e r i s e d in that for the displacement of the piston part (2) in the return direction, a pressure spring (13) is arranged between the piston part (2) and the bottom (3) of the cylinder part (1).

4. Device according to any one of claims 1-3 c h a r a c t e r i s e d in that the inlet channel (7) is provided with a closure device (22).