Surgery – Means for introducing or removing material from body for... – Treating material introduced into or removed from body...
Reexamination Certificate
1999-08-30
2001-01-09
Kennedy, Sharon (Department: 3763)
Surgery
Means for introducing or removing material from body for...
Treating material introduced into or removed from body...
C604S119000, C604S128000
Reexamination Certificate
active
06171280
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Technical Field
The present invention relates to precision aspirators, suited for use in automated liquid sample analyzers, for taking up liquid from containers by suction. In particular the invention relates to precision aspirators employing liquid suction tubes that can pierce caps sealing the mouths of containers holding diagnostic samples and reagents, and that can discriminate among such containers.
2. Description of Related Art
Automated liquid sample analyzers, for example, blood-sample analyzing machines, employ an aspirating pipette to take up a predetermined amount, or aliquot, of sample liquid such as blood plasma sequentially from a row of tubular sample containers. The sample containers are held in a sample rack that is transferred in container-by-container increments into an aspirating position beneath the pipette. Each container is paused in the aspirating position, in which a mechanism manipulating the pipette brings it down into the container, actuates suction through the pipette to take up an aliquot, brings the pipette back up, and shifts it to an ejecting position. In the ejecting position, the aliquot is ejected into, for example, a reaction vessel containing reagents for a blood-analyzing test.
Some of the containers loaded into the sample rack may be sealed, with a rubber cap for example, or otherwise stoppered. The tips of the needle-type aspirating pipettes used for taking up aliquots from sample containers are cut obliquely to pierce a sealed or stoppered container.
An aspirating tube having an aspiration aperture formed on its circumferential surface apart from the tip, so that when the aspirating tube penetrates a rubber cap, rubber debris does not clog the aspirating tube, as Japanese Laid-Open Pat. App. No. 9-304400 discloses, is known.
On the other hand, Japanese Pat. No. 2511549, corresponding to U.S. Pat. No. 5,201,232, discloses a liquid sampling device having a sampling probe for withdrawing sample liquids from open containers, as well as a sampling needle for closed containers. Therefore, the liquid sampling device is operable to suit either type of containers—capped (closed) containers, or uncapped (open) containers. Furthermore, the disclosed liquid sampling device distinguishes open containers from closed containers using a detector that reads an identification label or card provided on the container exterior.
Nevertheless, the device as taught in Japanese Pat. No. 2511549, in order to identify the containers from which it withdraws samples, requires special labels or cards affixed to the containers, as well as a detector to read them. Consequently, if the labels or cards are affixed improperly, the device cannot identify containers correctly. In addition, equipping the device with two kinds of aspirators makes the mechanism large and complex.
If for example a single aspirating tube is to be used for both open and closed containers, some situations make it desirable to provide the aspiration aperture in the tip of the aspirating tube. For instance, the desire to improve quantitating accuracy in micro-samples of a few &mgr;l, to decrease sample-liquid dead volume (the quantity that cannot be aspirated and remains in the container), or to decrease the amount of aspirating tube immersed into a sample liquid in order to prevent inter-contamination of the liquids necessitates that the aspiration aperture be in the tip of the aspirating tube. However, if the aspiration aperture is provided in the tip of the aspirating tube, the tube is likely to get clogged when it penetrates the cap of a closed container.
In conventional liquid sampling devices, the aspirating tube is shifted vertically to take up an aliquot, which operation requires relatively little force to bring the pipette down into an open container, yet considerably greater force to stab the pipette through a sealed container. Supplying large force for an open container leads to mechanical losses, hampers agility and, leads to operational problems such as damage to the aspirating tube by its being crushed on the bottom of the container due to the container's vertical position. For example, to shift horizontally the liquid aspirating tube and its large drive source if integrated into one unit confronts the practical problems that the unit cannot travel horizontally at high speed due to its large size and weight, and that the horizontal shifting mechanism then also must be large.
SUMMARY OF THE INVENTION
One object of the present invention is to enable correct identification of liquid sample containers by employing a container-identifying device of simple constitution.
Another object of the present invention is to prevent the aspiration aperture in the sharp tip of an aspirating pipette from becoming clogged.
A further object of the present invention is to enable manipulation of a sample-liquid aspirating pipette for both closed and open containers by accordingly supplying appropriate force, in an aspirator adapted for operation in, for example, an automated analyzer.
An aspirator in accordance with the present invention functions in an automated analyzer to aspirate liquid aliquots from a row of capped and uncapped containers in a sample rack. horizontally transferred by a sampler incrementally into an aspiration position. Essential components of the aspirator include a needle pipette having an obliquely cut aspiration tip, first and second aspirator manipulation units, external force sensing means associated with the first aspirator manipulation unit for detecting external force acting on the pipette, and liquid-surface detecting means operative through the pipette.
The first aspirator manipulation unit includes a first holder that retains the pipette vertically, and a first drive means that vertically translates the first holder into and out of a container in the aspiration position. The second aspirator manipulation unit includes a second holder configured to enclose the first holder, leaving a predetermined amount of play. A second drive means for the second aspirator manipulation unit cooperates with the first drive means to translate the second holder vertically in tandem with the first holder, and operates independently of the first drive means to drive the second holder against the first holder.
An aspirator controller is connected to the first and second drive means and is responsive to both the external force sensing means and the liquid-surface detecting means; accordingly the aspirator controls the first and second aspirator manipulation units.
The aspirator controller is programmed to actuate the first and second drive means to translate the first and second holders vertically in tandem. If no external force is detected acting on the pipette by the external force sensing means, the controller continues to direct the first and second drive means to bring the pipette down until it contacts liquid in a container in the aspiration position. If the needle pipette does not contact liquid in the container in the aspiration position after the first and second holders have been translated a predetermined distance, the controller halts the first and second drive means. If external force is detected acting on the pipette by the external force sensing means, i.e., if the pipette tip strikes the top of a capped or stoppered container, the controller halts the first drive means and continues actuating the second drive means. This operation presses the second holder onto the first holder to stab the pipette through the cap or stopper.
Therein, to prevent the punctured rubber in the cap from clogging the tip, the obliquely cut aspiration tip of said needle pipette is inner-rim chamfered.
The aspirator operates automatically and checks for the presence of a cap/stopper on each container. Accordingly, in translating the first and second holders downward to the container, if the pipette does not encounter a cap/stopper, the second holder remains separated from the first holder within the predetermined amount of play. Consequently, the first holder, retainin
Bandou Tadashi
Fukuda Kazuya
Imazu Masanori
Tsuru Yoshiyuki
Kennedy Sharon
Shinjyu Intellectual Property Firm
Sirmons Kevin C.
Sysmex Corporation
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