RU1775169C - Plunger micropipette - Google Patents

Abstract

SUMMARY OF THE INVENTION: A micropipette comprises a housing, a plunger, a plunger return spring, a screw sleeve interacting with the plunger through an emphasis, a drive nut, and dose rate reading means. At the tip is a means for mixing the accumulated doses. The mixing means is in the form of a compression spring from chemically selected doses. The mixing means is in the form of a compression spring of a chemically resistant material. One end of the spring is fixed by turns on the housing, the other end of the spring is straightened and coaxially mounted in the outlet of the tip. 1 il

Description

The invention relates to the field of biochemistry and medicine, in particular to devices for the precise dosing of micro-quantities of liquids and can be used in laboratory practice to measure the doses of solutions while stirring them, for example, when conducting fast reactions in the tip of a micropipette.

An object of the invention is to simplify a pipette.

The drawing shows a General view of the pipette in section.

The plunger micropipette contains a housing 1, an e-return spring 3 of the plunger 2, a screw sleeve 4 interacting with the plunger 3 through an emphasis 5, a drive nut 6, a dose rate reading device 7 and a replaceable tip 8 sealed on the housing 1. A compression spring is installed in the cavity of the tip 8 9, made of chemically resistant material, one end of which is fixed by turns

10 on the housing 1, and the other is straightened and freely passed through the outlet

11 of the tip 8. The spring 9 can be made of thin (0 0.1-0.2 mm) stainless or non-chrome wire.

The pipette works as follows.

To collect the first dose of the solution, move plunger 2 down to the stop and immerse tip 8 in the solution (not shown in the figure) by 2-3 mm.

When the plunger 2 moves upward under the action of the return spring 3 to the intermediate position defined by the stop 5, a vacuum forms in the tip 8 and the liquid is sucked into the tip 8. The volume of liquid taken in is determined by the amount of movement of the plunger 2 and is controlled by the reporting device 7 ,

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To collect the next dose, immerse tip 8 in a second solution,

When the nut b of the drive of the adjustable stop 5 is rotated, the stop 5 moves relative to the housing 1. Under the action of the return spring 3, together with the stop, the plunger 2 moves up to the selected position.

8 of the cavity of the tip 8, a vacuum is formed and a liquid is sucked in the tip, the volume of which is determined by the amount of movement of the plunger 2 and is controlled by a reading device.

Subsequent doses are taken in a similar manner until the plunger 2 reaches its highest position. The number of steps is determined by the number of mixed solutions,

To mix the accumulated doses, the end of the compression spring 9, freely passed through the outlet 11 of the tip 8, is abutted horizontally against the bottom of the chemical glassware (not shown in Fig.).

Holding the pipette in a vertical position, perform multiple reciprocating movements of the pipette in the vertical direction. In this case, the distance between the turns of the compression spring 9 changes and intensive mixing of the doses of fluid collected in the cavity of the tip 8 takes place.

A prerequisite for the fluid not to remain between the coils of the spring is that the gravity of the fluid enclosed in the chain between the coils of the spring exceeds the surface tension forces holding the fluid for this purpose. This condition is provided experimentally by the selection of the pitch of the coil of the spring, while the spring pitch (cylindrical or conical) is increased until the drop ceases to linger between

turns. The spring coil pitch is experimentally selected with distilled water, which has the maximum surface tension coefficient of all known liquids. No selection of spring pitch during operation of the pipette is required.

This pipette allows, in comparison with the prototype, to allow small doses to be dispensed, eliminates metering errors due to the complete displacement of liquid from the tip.

The pipette allows stirring at any time while the fluid is in the tip.

The present pipette is much simpler than the known one due to the fact that no additional devices (rotating magnet) are needed for mixing.

In addition, when using the proposed technical solution in multichannel pipettes, it is possible to carry out an immunological rapid analysis directly at the tips of the pipette.

Claims (1)

SUMMARY OF THE INVENTION A plunger micropipette comprising a housing, a plunger, a plunger return spring, a screw sleeve interacting with the plunger through an abutment, a drive nut, dose rate reading means, a replaceable tip mounted tightly on the housing, and mixing fluid collection means disposed in the tip, different from that that, in order to simplify the pipette, the means for mixing the collected liquids is made in the form of a compression spring of a chemically resistant material, one end of which is fixed by turns on case, and the other is straightened and coaxially mounted in the outlet of the handpiece. Yu eleven /