The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Aug. 27, 1996
Filed:
Dec. 16, 1994
David L Boger, Mishawaka, IN (US);
Doraiswami Jaichandra, Granger, IN (US);
Donald L Jaworski, Mishawaka, IN (US);
Joseph E Perry, Osceola, IN (US);
Bayer Corporation, Elkhart, IN (US);
Abstract
A fluid sensing pipette includes an outer conductive tube forming a first electrode and an inner conductive tube forming a second electrode. The inner conductive tube is disposed concentrically within the outer conductive tube. To insulate the inner conductive tube from the outer conductive tube, the inner conductive tube is coated with a thin, uniform, and consistent Parylene coating. A hydrophobic polymeric tube is disposed concentrically within the inner conductive tube to prevent cross-contamination between different biological samples aspirated into the pipette. The inner and outer conductive tubes are separately coupled to a level detection circuit which permits the pipette to detect entry of the pipette into a conductive fluid. The level detection circuit determines the impedance between the first and second electrodes and produces a control signal in response to the impedance falling below a predetermined threshold. A hydrophobic polymeric plug is disposed between the inner conductive tube and the polymeric tube in close proximity to a distal end of the polymeric tube so as to prevent fluid from entering between the inner conductive tube and the polymeric tube.