Title: Moisture sensing systems for electrically operated liquid-handling devices

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Claims: We claim:

1. A fraction collector comprising:

a support;

an upwardly open tray mounted on said support and having a pitched surface;

electrically operated means on said support for carrying an array of upwardly open vessels successively past a location fixed relative to said support and above said tray;

a source of liquid mounted on said support;

a dispensing tip on said support for discharging said liquid into successive vessels at said locations;

an electrically operated valve interconnecting said source and said tip for controlling the flow of liquid to said vessel;

liquid-detector means at the bottom of said pitched surface responsive to the presence of liquid thereat; and

an electric switch operated by said liquid-detector means for deenergizing said valve and said electrically operated means upon the detection of liquid by said liquid-detector means.

2. The apparatus defined in claim 1 wherein said liquid-detector means includes a spring biasing said switch into a nonconductive condition; and

a moisture-destructible element retaining said switch in a conductive position against the force of said spring.

3. The apparatus defined in claim 2 wherein said destructible element is a strip of filter paper held under tension by said spring and capable of being pulled apart when wetted.

4. The apparatus defined in claim 2 wherein said destructible element is a tube of filter paper held under compression by said spring and adapted to be collapsed when wetted.

Other info:

Inventors: Gelfand, Daniel (Cliffside Park, NJ, US)

Application Number: 472901
Filing Date: 1974-05-23
Publication_date: 1976-03-16
Assignee: Buchler Instruments, Div. of Searle Analytic, Inc. (Fort Lee, NJ)
Primary Class(es): 141/192 137/312, 141/130, 200/61.04
Other Classes:
US Patent Ref:

1174827	Mar, 1916	Conway	200/61.
2482448	Sep, 1949	Wiest	200/61.
2531159	Nov, 1950	Rowell	137/312.
3205921	Sep, 1965	Packard et al.	141/130.

Other Refs:
Primary Examiner: Aegerter, Richard E.
Assistant Examiner: Schmidt, Frederick R.
Attorney: Ross; Karl F., Dubno; Herbert