Methods and apparatus for pipetting and/or titrating liquids using a hand held self-contained automated pipette
US4671123A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Feb 16, 1984 |
| Grant date | Jun 9, 1987 |
| Priority date | — |
| Expiry date | Feb 16, 2004 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10T436/2575
- WIPO fieldChemical engineering
- WIPO sectorChemistry
Abstract
A hand held self-contained automated pipette for portable operation having an electrically operated digital linear actuator. The actuator preferably includes a stepper motor driving a rotor. A threaded screw is coaxially positioned within the rotor and is connected to an actuator shaft having elongate grooves slidable in a guide for preventing shaft rotation so that precise linear motion is imparted to the shaft. A pipetting displacement assembly having one of various sizes is removably attached for actuation by a common actuator including programmed movement of a displacing piston in a displacement cylinder to optimize air interface volume, neutralize variations in vacuum pipette effects, and provide an accommodated stroke and readout for improved accuracy while pipetting and/or titrating different ranges of volumes. A control circuit is provided so that the back EMF of the stepper motor coils is recirculated when power is duty-cycled off for power conservation. Conversely, recirculation is switched off when power is duty-cycled on for minimizing losses. Recirculation is switched off when coils are commutated which produces a rapid magnetic field collapse for assuring high torque.…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.