FI105782B - Method and device for the dosing of a liquid - Google Patents

Description

FIELD OF THE INVENTION The present invention relates to a device for dispensing, transferring, diluting, titrating, mixing, or incorporating all or some of these into a suction device, such as a mechanical or electronic pipette. a removably attachable tip for receiving a fluid sample.

Said aspirators include a tip portion associated with a body portion having a disposable tip 10 removably connected to an open end away from the body portion and having a sample space for receiving a fluid sample, and having a cylindrical space in the tip portion for receiving .

When used in the following description, the words suction device or pipette are intended to refer generally to any type of suction device as defined above that functions as a pipettor, dispenser, diluent, titrator or mixer, or in addition to all or some of these.

Pipettes have been in use for about three decades, from which 20 fluid reservoirs, i.e., pipette tips, have been spilled into the inner parts of the pipette, for example by careless use of the pipette, or in the form of liquid vaporized molecules. Contamination of the inside of the pipette will result in • compromising occupational safety and reducing or even eliminating the reliability of the pipette itself. This is, of course, unacceptable in precision laboratory work.

Because of these problems, pipette manufacturers recommend that pipette users periodically disassemble and clean these parts. Almost invariably this procedure involves the re-lubrication of the piston and seal of the pipette v 30 and often also the re-calibration of the pipette, ie pipettable, dispensable, etc.

the liquid volumes are set to match the volumes set on the pipette scale. In addition to being a cumbersome and laborious operation, such a pipette disassembly and reassembly does not guarantee that the pipette is free of infectious agents or other 2,105,782 contaminants such as DNA or RNase interferences that interfere with PCR work. Therefore, some pipette manufacturers have begun to manufacture pipettes that are claimed to be sterilized in an autoclave. However, autoclave sterilization does not remove DNA or RNase contamination from the pipette sections. It is extremely cumbersome 5 and many times it damages parts of the pipette itself to such an extent that the pipette no longer functions accurately and reliably. When using a pipette after sterilization, it is very possible that it is already contaminated by first pipetting.

U.S. Patent No. 5,406,856 discloses a suction device for use with disposable tips 10 having a tip inserted into a liquid having an opening for collecting and withdrawing a fluid sample, and a portion of the body of the suction device fitting into the tip of the suction device. The shape of this solid part and, at the same time, its volume can be changed by means of a member at the tip of the suction body. In this solution contamination can be prevented, but the disposable tip used therein is a special tip. It should also be noted that this special tip must be fitted inside the tip portion of the suction body, whereby the tip portion must be made larger than the disposable tip itself.

U.S. Patent No. 4,444,062 discloses a multi-channel suction device in which a flexible diaphragm is attached between the suction body and the tip rack to be attached thereto so that the pins in the movable piston inside the suction body come into contact with the diaphragm when the piston is depressed. In this solution, the film is attached to either the lower surface of the body or the top surface of the tip rack or two films are used, one attached to the lower surface of the body and the other to the top surface of the tip rack. The tip rack is in turn fixed to the frame by a screw connection. In one embodiment of the present invention, a tip rack assembly formed by a tip rack with tubing attached thereto and a membrane attached to the top portion of the tip rack and a top rack can be a single-use plastic extruded portion secured to a suitable quick-connect socket. However, the tip rack assembly of this patent cannot be mounted on the tip portion of the suction body as the tip of the present invention.

3, 105782

The disposable walker solution according to the invention avoids the above disadvantages. Thus, the tip according to the invention is characterized in that a membrane made of a flexible, reversible deformation material is fitted in the visitor's sample space gas and liquid tightly against the inner surface of the disposable visitor sample space.

The disposable suction device used with the tip itself may be known per se as manual or, for example, electric, and may be self-contained or as part of a device such as a pipette.

10

According to the invention, a diaphragm member comprising a membrane made of impermeable, flexible, reversible deformation material is disposed in a tip sample space to close a gas and liquid tight disposable tip sample space, wherein the suction body is through the opening in the sample space of the disposable walker, can be brought into contact with said membrane to cause a change in volume of the space delimited by the diaphragm member from the sample space for taking and removing the sample.

20

According to the invention, the diaphragm member disposed in the sample space of the disposable tip is located at a location suitable for sampling the disposable tip. The shape of the membrane member naturally depends on the shape of the sample chamber. According to a preferred embodiment of the invention, it is sealingly fitted into the sample space in connection with the manufacture of a disposable tip, for example by welding or gluing. According to another preferred embodiment, the membrane is secured to a frame which is gas and fluid tight against the inner surface of the sample space of the disposable tip, and where it remains in its intended position, for example by frictional force, preferably without special fastening means. The diaphragm member may also engage through the shoulders, projections, pins, or the like on the inner surface of the disposable tip 30 through the inside surface of the disposable tip sample chamber.

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In a preferred embodiment of the invention, the diaphragm is mounted on a rack having members that are operable to contact the piston or shoulder members, pins, or the like in the cylindrical airspace of the suction head to disengage the disposable tip out of the aperture in the tip of the suction device.

The tip of the suction device according to the invention is also suitable for laboratory work based on the PCR technique, since the membrane member in the disposable tip 10 according to the invention prevents DNA and RNase contamination of the inner pipette and thus cross-contamination of different samples and reaction mixtures.

The invention will now be described, by way of example, with reference to the accompanying drawing, in which Figure 1 is a longitudinal cross-sectional view of a suction pipette with an interchangeable tip according to the invention, Figure 2 is an enlarged view of the tip of Figure 1; 2 shows an alternative embodiment of the membrane member of FIG.

1-3, the same reference numerals for like parts are used. In Figure 1 of the drawing-25, the suction device, or pipette, is designated as a whole by reference numeral 1 and consists of a body part 2 and an associated tip part 3. The tip ·. piston 5 is slidably movable in the cylindrical air space 4 of the portion 3, the end 6 of the tip portion 3 includes an opening 7 through which the piston member 5 may extend into the sample space 9 of the disposable tip 8.

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Figure 2 illustrates an embodiment of the invention in which the diaphragm member 11 is fixed to seal to the inner wall of the sample space 9 of the disposable walker 8. In this embodiment, the diaphragm 12 is suitably mounted, e.g., on the frame 13, in the sample space 9 of the disposable tip 8 so that it does not come into contact with the sample 10.

* 5

In another preferred embodiment of the invention shown in Figure 3, the inner wall of the sample space 9 of the disposable tip 8 has projections, shoulders, pins or other members 14 extending into the sample space 9 against which the frame 13 can be brought into contact.

10

According to another embodiment, the diaphragm member 11 is preferably attached to the sample space 9 of the disposable walker 8 during its manufacture of a disposable tip on its inner wall, for example by welding or other suitable gas and liquid tightness guaranteeing method.

15

In a preferred embodiment of the invention, the frame 13 can be brought into contact with a shoulder 15 in the piston member 5 of the suction device 1 for moving the disposable tip 8 and the diaphragm member 11 attached thereto by the movement of the piston member 5. In another alternative embodiment 20, a telescopic telescoping extension extending longitudinally towards and away from the tip 6 of the tip portion 3 of the suction device 1, with respect to the piston 5, wherein the extension pushes the disposable tip 8 and the diaphragm member 11 attached thereto from the tip portion 3 of the suction device 1.

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Claims (5)

6 105782 Patent Claims A detachable tip for suction device (1) for dispensing liquid, characterized in that a membrane member (11) is fitted in the sample space (9) of the tip (8) gas and liquid tight against the inner surface of the sample space (9). comprising a diaphragm (12) made of a resilient deformable material with which the movable member (5) at the tip (3) of the body of the suction device (1) is brought into contact with the space defined by the sample space (9) of the disposable tip (8) of the diaphragm to change the volume for sampling and / or removal. Tip according to Claim 1, characterized in that the diaphragm (12) is fixed to the frame (13), which in turn is fixed to the tip (8) against the inner surface of its sample chamber (9) in a gas tight manner. 15 Tip according to claim 1 or 2, characterized in that the membrane (12) is attached to a removable frame (13). Tip according to Claim 2 or 3, characterized in that the inner wall of the tip (8) of the visible space (9) has projections, shoulders, pins or other members (14) extending into the sample space (9), against which the frame (13) with its attached diaphragm l (12) being contactable for mounting the diaphragm member (11) against the inner surface of the sample space (9) of the tip (8) in a gas tight manner. A method for dispensing fluid by means of a suction device having a tip portion (3) enclosing a cylinder space (4) having a reciprocating member (5) and a removably attached tip (8), characterized in that the member (5) is brought into contact • a membrane member (11) of a resilient, reversible deformation material of a membrane member (11) formed in a gas and liquid tight seal (9) against the inner surface w of the tip (8) sample chamber (9); ) for changing the volume delimited by the disposable tip (8) from the sample space (9) for sampling and / or removal, and for bringing the member (5) into contact with the tip (8) of the caliper (13) for detaching the membrane member (11) attached thereto from the tip portion (3) of the suction device (1). t 5 Patent claims