Patent ID: 6322752
Filing Date: 2001-11-27
Classification: G01N

Abstract:
Apparatus for aspirating a volume of liquid from a container and for subsequently dispensing a desired predetermined volume of the aspirated liquid, said apparatus comprising:(a) at least one aspiration probe having a tubular housing with a proximal end and a distal end adapted to access a liquid in a container, the tubular housing having an internal volume substantially equal to said desired predetermined volume of liquid to be dispensed;(b) aspiration means for causing liquid in the container to enter the distal end of the aspiration probe and to completely fill the tubular housing, whereby the aspiration probe contains said desired predetermined volume of liquid;(c) sensing means for sensing that the tubular housing is completely filled with aspirated liquid, said sensing means comprising (i) a first liquid detector for sensing aspirated liquid that has passed completely through the aspirating probe, and (ii) a second liquid detector for sensing that the distal end of the aspirating probe has remained in the contained liquid during aspiration;(d) means operatively coupled and responsive to the sensing means for trapping aspirated liquid in the aspirating probe, said trapping means comprising a shear valve operatively connected to the proximal end of aspirating probe; and(e) means for dispensing the trapped aspirated liquid from the distal end of said aspiration probe.