Measuring and testing – Sampler – sample handling – etc. – Capture device
Patent
1992-12-30
1994-09-06
Noland, Tom
Measuring and testing
Sampler, sample handling, etc.
Capture device
7386416, B01L 302, G01N 114
Patent
active
053437691
DESCRIPTION:
BRIEF SUMMARY
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention concerns a procedure for filling and emptying a pipette with volumetric exactitude. The invention further concerns a pipette.
2. Description of the Related Art
In the art such pipettes are known for handling liquids, e.g. for liquid transfer, dilution, dispensing, mixing, titration etc., in which the plunger is operated either manually or with a particular mechanical contrivance, such as an electric motor.
In electrically operated single and multiple passage pipettes, the problem is their fairly bulky size, resulting from the large size of the requisite electric motor, e.g. a step motor or DC motor, and from the large size of the current source which this motor requires. Furthermore, the size of the pipette is increased, and its construction made complex, by the electronics needed to regulate and operate the pipette. The complex electronics moreover introduces a risk of malfunction which cannot be ignored. Furthermore, pipettes of prior art do not meet all requirements as regards dispensing accuracy and reproducibility.
The object of the present invention is to eliminate the drawbacks just mentioned. Particularly, the object of the invention is to provide a novel procedure for filling and emptying a pipette with higher quantitative accuracy than before, and a pipette which is simple in design, yet at the same time accurate and offering many different modes of use.
Regarding the features characterizing the invention, reference is made to the Claims section.
SUMMARY
In the procedure of the invention, the desired liquid quantity is transferred, making use of pressure in a cylinder space produced with the aid of a cylinder/plunger combination, into, respectively out from, a liquid volume. As taught by the invention, the travel of the plunger is measured as the plunger is being moved, that is when liquid is being moved into or out from the liquid volume, this distance travelled by the plunger being proportional to the quantity of liquid transported, and the plunger is arrested when the travel is consistent with the predetermined liquid quantity to be transferred. The plunger is advantageously stopped with the aid of a brake means.
In an embodiment of the invention, the plunger is moved with the aid of a threaded rod and/or sleeve, measuring the rotation of this threaded element. The plunger can be stopped by the aid of a brake means acting on the threaded rod and/or sleeve. The distance travelled by the plunger can be found from the rotation.
The means of the invention for liquid handling comprises a cylinder volume; a plunger which has been fitted into the cylinder volume to be reciprocatingly movable; a liquid volume communicating with the cylinder volume; an operating means for moving the piston in order to fill and empty the liquid volume of the pipette at least in part with quantitative exactitude by moving the plunger. As taught by the invention, the pipette comprises a measuring means for measuring the plunger travel and a control means for controlling e.g. the operating means and, by its mediation, the plunger movements. The control means may comprise a data processing unit, such as a microprocessor. The operating means advantageously comprises a brake means arranged to arrest the plunger by control from the control unit with quantitative exactitude in conformity with the desired filling or emptying volume.
In am embodiment of the invention, the operating means comprises a threaded rod and sleeve assembly, and a power means. The power means is advantageously disposed to rotate one element of the threaded rod and sleeve combination, and the other element is connected to the plunger in order to move the plunger. The measuring means may be disposed to measure the rotation of the threaded rod and the sleeve relative to each other. The measuring means may comprise a detector for detecting the rotation of the rotatable part of the threaded rod and sleeve assembly, on the basis of this rotation being determined e.g. the travel of t
REFERENCES:
patent: 3248950 (1966-05-01), Pursell et al.
patent: 3915651 (1975-10-01), Nishi
patent: 4058370 (1977-11-01), Souvaniemi
patent: 4224281 (1980-09-01), Thieme et al.
patent: 4345483 (1982-08-01), Paletta et al.
patent: 4567780 (1986-02-01), Oppenlander et al.
patent: 4790176 (1988-12-01), Marteau d'Autry
patent: 4821586 (1989-04-01), Scordato et al.
patent: 4896270 (1990-01-01), Kalmakis et al.
patent: 4964533 (1990-10-01), Allington et al.
patent: 4988481 (1991-01-01), Jarvimaki et al.
patent: 4995532 (1991-02-01), Knodel
Ekholm Pertti
Suovaniemi Osmo
Biohit Oy
Noland Tom
LandOfFree
Procedure for filling and emptying a pipette, and pipette does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Procedure for filling and emptying a pipette, and pipette, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Procedure for filling and emptying a pipette, and pipette will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-1322457