Apparatus and method for detecting liquid penetration by a container used for aspirating and dispensing the liquid

Claim 1

Apparatus for aspirating and dispensing liquid and including a probe for removably mounting a container having an aspirating and dispensing aperture; pressurizing means fluidly connected to said probe for generating an operative pressure differential relative to atmospheric pressure, within a mounted container; moving means for advancing said probe and such mounted container toward, and away from, a nominal liquid level location; and a control system for said apparatus, which control system comprises a) means for controlling the advance of said probe so as to move repeatedly in increments between periods of rest, b) means for actuating said pressurizing means during said rest periods only to generate a pressure differential in such container, relative to atmospheric pressure, that is sufficient to indicate whether such container aperture is closed by the liquid, c) means for detecting and signalling the pressure produced within such container by said pressure differential; and d) means for comparing the signalled pressure against a reference value determinative of the presence of liquid in such container aperture.

Claim 3

A method for detecting that a dispensing container of an aspirating and dispensing apparatus has penetrated into a liquid through an air-liquid interface, said apparatus including a probe for removably mounting a container having an aspirating and dispensing aperture; pressurizing means fluidly connected to said probe for generating an operative pressure differential relative to atmospheric pressure, within a mounted container; moving means for advancing said probe and such mounted container toward, and away from, a nominal liquid level location: and controlling said pressurizing means consistent with the location of said mounted container: said method comprising the steps of a) controlling the advance of said probe to repeatedly move towards the liquid in increments between periods of rest, b) actuating said pressurizing means during said rest periods only to generate a pressure differential in such container, relative to atmospheric pressure, sufficient to indicate whether such container aperture is closed by the liquid. c) detecting and signalling the pressure produced within such container by said pressure differential: and d) comparing the signalled pressure against a reference value determinative of the presence of liquid in such container aperture.

Claim 4

A method for detecting that a dispensing container of an aspirating and dispensing apparatus has penetrated into a liquid through an air-liquid interface, said apparatus including a probe for removably mounting a container having an aspirating and dispensing aperture; pressurizing means fluidly connected to said probe for generating an operative pressure differential relative to atmospheric pressure, within a mounted container; moving means for advancing said probe and such mounted container toward, and away from, a nominal liquid level location: and controlling said pressurizing means consistent with the location of said mounted container: said method comprising the steps of a) controlling the advance of said probe to repeatedly move towards the liquid in increments between periods of rest, b) actuating said pressurizing means during said rest periods only to generate a pressure differential in such container, relative to atmospheric pressure, sufficient to indicate whether such container aperture is closed by the liquid. c) detecting and signalling the pressure produced within such container by said pressure differential: and d) comparing the signalled pressure against a reference value determinative of the presence of liquid in such container aperture.