Patent ID: 8146625

Claim:
An apparatus for preventing either the introduction of air into a liquid aspirated from a container through an aspiration tube passing through a container cap, or the over-filling or no-filling of a container by a liquid dispensed through a dispensing tube passing through a container cap, said apparatus comprising a pair of detectors, one operating to detect that such container cap is properly positioned on and secured to a liquid container from which liquid is to be aspirated, or into which a liquid is to be dispensed, and the other detector operating to detect that the level of liquid in the container is either above or below a predetermined level, wherein said one detector comprises a proximity switch mounted in said container cap for sensing the proximity between said cap and a mouth of a container to which said cap is to be attached, and said other detector comprises a float switch, and wherein said proximity switch comprises a switch-actuating member that is slidably-mounted on either of said aspiration or dispensing tubes for movement between first and second axially-spaced positions, and a spring for urging said switch-actuating member towards a switch-opening position.