Positive-displacement pipette
OwnerEric Marteau d'Autryinventor
Life of this patent
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Abstract
High-precision positive-displacement pipette having a nozzle with calibrated capillary channel and capable of disengageably fitting together with the free lower end of the pipette body. A piston fits tightly in the capillary channel and is controlled by a manually operable control rod equipped with a gripping device with which it grips the piston. An opening at this end of the body permits at least a part of the gripping device to pass through and come into contact with a stop provided on the inner surface of the nozzle so as to ensure the simultaneous ejection of the nozzle and of the piston which remains captive in the capillary channel.
Claims13
A high-precision positive-displacement pipette for sampling and dispensing of small quantities of liquid, comprising:
- a substantially tubular pipette body;
- calibrated capillary means at the lower end of said pipette body;
- tight fitting piston means movable in said capillary means;
- main spring means exerting an upward elastic restoring force against said piston means;
- a control rod projecting from the upper end of said pipette body;
- means gripping the upper end of the piston means;
- resilient members equipping said gripping means and movable apart radially by displacement;
- second spring means having a resistance much higher than that of the main spring means and arranged for movement in translation with said control rod, said second spring means exerting a force opposing said displacement of said resilient members;
- wherein the improvement comprises nozzle means associated with said capillary means and capable of engaging, by fitting together, with the free lower end of the pipette body, said lower end of the pipette body defining an opening permitting the passage of at least a part of said gripping means, and stop means provided on the inner surface of said nozzle means to come into contact with said gripping means and thereby ensure the simultaneous ejection of said nozzle and of the piston which remains captive in the capillary means.
Dependencies are inferred from the claim text.