JPS595016B2 - pipetting device - Google Patents

Description

[Detailed description of the invention] The present invention relates to pipetting devices.

BACKGROUND OF THE INVENTION Pipetting devices are widely used to take a predetermined amount of a liquid sample and transfer it to another container for analysis, inspection, testing, etc., and various types are known.

Among these, the present invention is particularly suitable for a type of pipette device called a so-called micropipette, which has a sample collection amount of about 5 to 200 μm.

In the case of a micropipette, a thin glass tube or the like is usually used as a liquid suction tube to collect and contain a predetermined amount of liquid, and the liquid sample collected in this glass tube is then placed in a predetermined position, such as in a test tube for testing. is discharged.

For example, as a micropipette used for blood tests, etc., a rubber tube is connected to the top end of a glass capillary with graduated lines, the other end of the rubber tube is held in the mouth, a predetermined amount of blood is collected by inhalation, and the blood is exhaled. There are known devices that discharge blood through movement, but it is difficult to visually check whether the blood has been sucked up to the scale line position correctly, and the blood in the capillary cannot be completely discharged. Therefore, there may be errors in the accuracy of the amount collected and discharged, and in some cases, the saliva of the examiner may be mixed in when expelling the inhaled sample, or samples such as blood may accidentally flow into the examiner's mouth when inhaling the sample. There was also the risk of bacterial infection.

The present invention aims to eliminate such drawbacks of conventional devices and provide a highly accurate and easy-to-operate pipetting device. A housing equipped with a liquid suction tube capable of accommodating an aspirated liquid sample at its lower end, and a cylinder provided within the housing for applying vacuum pressure to the upper end of the liquid suction tube to aspirate the liquid sample into the liquid suction tube. the housing includes an air inlet connected to a source of compressed air and controlling communication between the inlet and the upper end of the liquid intake tube; a first valve device that is normally closed and an operating device that operates the valve device; and an operating device that connects the air inlet and the outside of the housing under normal conditions and communicates between the air intake and the outside of the housing when the first valve device is operated. and a second valve device for blocking communication between the pipetting device and the pipetting device.

The liquid suction tube may be a glass tube (or glass capillary tube) with graduations or indicator lines, or may be a glass tube of a predetermined length defining a predetermined volume.

Since the first and second valve devices are provided to open and close alternately, it is possible to use extremely simple air compressors, such as those driven by electric motors, as the compressed air source, and a compressed air storage tank, pressure regulating valve, etc. can be used as the compressed air source. There is no need to provide one.

Since the discharge is carried out by compressed air, the liquid is completely discharged, and when discharging a liquid sample into a reagent, for example, by continuing to supply compressed air for a while after the discharge is completed, a good bond between the liquid sample and the reagent is maintained. Mixing can be achieved.

Preferred embodiments of the invention are illustrated in the accompanying drawings.

In FIG. 1, an operating screw 1 connected to a piston 3 is screwed into the upper end of a housing consisting of upper and lower bodies 2 and 6 that are screwed together, and by rotating the operating screw 1 with a fingertip, the piston is 3 moves up and down inside the cylinder 5.

At the lower end of the housing there are fitted a fitting 12, a sleeve 20, a seal 18.1 and a glass capillary tube 26 with graduations 27.
9. Attached by connector 14.

The outer diameter of the glass tube 26 is sealed and held by the packing 19 and the connector 14.

Glass tube 26 has a precisely finished inner diameter, and the volume below graduation line 27 limits the desired dispense volume.

A valve housing 7 is attached to the lower body 6 via a connector 4, and valve bodies 9 and 10 are integrally fixed within the valve housing 1 and are movable in the lateral direction in FIG. The opposing conical valve portions are engageable in cooperating valve seats 15, 15, respectively.

The valve body 10 is integrally fixed to a push button 8, and the push button 8 is pressed to the right by a spring 21.

This causes the valve portion provided in the valve body 9 to engage with the valve seat, closing this valve, that is, the first valve.

An air connector 11 is provided in the valve housing 7, and compressed air is supplied to an intermediate position between the valve seats 15,15.

When the first valves 9 and 15 are closed, the right valve, that is, the second valve, which is composed of the valve body 10 and the cooperating valve seat 15, is open, and the air compressor (not shown) is The compressed air is discharged to the atmosphere through a second valve.

By pressing the pushbutton 8, the second valve is closed and the first valve is opened, and the compressed air passes through the first valve and acts on the upper end of the liquid suction tube 26 to discharge the liquid.

The liquid is sucked in by rotating the operating screw 1 with a fingertip to raise the piston 3 within the cylinder 5, so it is extremely easy and quick, and it is possible to visually confirm that the liquid has risen to the correct scale line position.

Since the liquid is discharged by compressed air by pressing the push button 8, the discharge is quick and complete, and by continuing to discharge the compressed air for about 10 seconds after the liquid has been discharged, for example, the liquid can be removed from the reagent. When discharging into the glass tube, the remaining liquid inside the glass tube is completely pushed out, and the liquid is further mixed.
Stirring can also be performed at the same time.

FIG. 2 shows a modification of the connector when the liquid suction pipe is of a so-called full-length type, in which the glass tube 31 is replaced by a glass sphere 29.
The glass sphere 29 is supported by a sealing connector 30 made of synthetic resin or the like at the lower end of the lower body 6 , and the glass sphere 29 is screwed into the lower end of the lower body 6 by the connector 28 .

FIG. 3 is a partial cross-sectional view showing a modification of the piston operating device. In this case, the operating screw 1 is hollow and is not directly connected to the piston 3, and the piston 3 is moved by a spring 34 to the operating screw 1. It is pressed against the downward facing shoulder 1'.

An intermediate shaft 33 is fixed to the piston 3, and a screw cap 32 is threadedly engaged with the intermediate shaft 33.

The portion 33' of the intermediate shaft 33 has a non-circular cross section, and by fitting into a correspondingly shaped hole of the operating screw 1, rotation of the intermediate shaft 33 is prevented.

In this case, the compressed air valve housing is attached to the upper body 2, and a groove 5' is provided on the outer surface of the cylinder 5 for guiding the introduced compressed air to the lower part of the housing.

In this arrangement, the push button 8 and the operating screw 1 are located closer to each other than in the embodiment shown in FIG. 1, making it easier to operate with a fingertip.

During operation, in addition to being able to perform the same operations as in the embodiment shown in FIG. 1, one-touch suction of the sample by releasing the screw cap 32 from the depressed state and fine adjustment using the operating screw 1 can be used together. Furthermore, after discharging the sample into the diluent, the screw cap 32 is pressed down and released several times while the tip of the glass tube is inserted into the diluent, thereby removing the remaining liquid that adheres to the inner wall of the glass tube. You can also wash it off.

By pushing out the remaining liquid in the capillary tube through compressed air, the accuracy when using a viscous liquid such as blood as a sample can be reduced to ±2% or less, compared to about 5 in the case of a conventional device. It can be done.

Furthermore, by using an operation of cleaning the inside of the tube with a diluent, the accuracy can be reduced to within ±1 factor.

[Brief explanation of drawings]

FIG. 1 is a longitudinal sectional view of a pipette device shown as an embodiment of the present invention. FIG. 2 is a longitudinal sectional view showing a modification of the liquid suction pipe in FIG. 1. FIG. 3 is a partial vertical sectional view of a pipette device including a modification of the piston operating device in FIG. 1. 1 is an operating screw, 2 is an upper body, 3 is a piston, 5 is a cylinder, 6 is a lower body, 7 is a valve housing, 8 is a push button, 9 and 10 are valve bodies, 11 is an air connector, 12 is a capillary fitting , 4 is a valve housing connector, 14 is a connector, 1
5.15 is a valve seat, 26.31 is a liquid suction tube shown as a capillary tube, 32 is a screw cap, and 21.34 is a spring.

Claims (1)

[Scope of Claims] 1. A housing equipped with a liquid suction tube at the lower end, which has a liquid suction and discharge opening and can accommodate a predetermined amount of sucked liquid sample, and applies vacuum pressure to the upper end of the liquid suction tube. at least a cylinder-piston device disposed within the housing for aspirating a liquid sample into the liquid suction tube, and a cylinder-piston operating device disposed at the upper end of the housing; a normally closed valve device that controls communication between the inlet and the upper end of the liquid suction pipe, and an operating device that operates the valve device;
A pipette device comprising: a second valve device that communicates the inlet with the outside of the housing under normal conditions and blocks the communication when the valve device is operated. 2. The pipetting device according to claim 1, wherein the liquid suction tube is a capillary tube. 3. The pipetting device according to claim 1 or 2, wherein the cylinder piston operating device includes a manually rotatable operating screw. 4. A pipetting device according to any one of claims 1 to 3, wherein the operating device for operating the valve device includes a push button. 5. The pipette device according to claim 4, wherein the two valve devices are coaxially and integrally provided.
and a second valve member, under normal conditions, the first valve member engages with the first valve seat and the second valve member is separated from the second valve seat, and when the push button is operated, both valve members are engaged. A pipetting device characterized in that the pipette is adapted for axial movement such that the first valve member moves away from the first valve seat and the second valve member engages the second valve seat. 6. In the pipette device according to claim 3, the cylinder-piston operating device includes a piston that is normally pressed by a spring toward a manually rotatable operating screw, and a piston that is moved away from the operating screw. The pipetting device as described above, comprising: a push-down device provided at the upper end of the pipette device so as to be able to push down the pipette device; and an adjustment screw for adjusting the amount by which the piston is pushed down by the push-down device.