Fluid sensing pipette
US5550059A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Dec 16, 1994 |
| Grant date | Aug 27, 1996 |
| Priority date | — |
| Expiry date | Dec 16, 2014 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10T436/2575
- WIPO fieldMeasurement
- WIPO sectorInstruments
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.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.