Charles L Bell

US Patent:

44760957, Oct 9, 1984

Filed:

Apr 12, 1974

Appl. No.:

5/460297

Inventors:

Robert L. Scott - Medfield MA
Samuel Nejame - Medfield MA
Charles S. Jacobs - Mountain Lakes NJ
Charles A. Bell - Weston MA

International Classification:

G01N 3116

US Classification:

422 75

Abstract:

A fluorometric titrator has means to transfer a pipette between first and second positions and a buret for a chelating agent has a reversible drive powered either by a pulse generator or an oscillator. Valve controlled means are operable to place the buret in communication with the pipette or a reservoir. In the first position of the pipette, a precise sample volume is aspirated into it by the buret, then driven by the oscillator and in its second position and with the buret drive reversed but still powered by the oscillator, the sample volume is discharged from the pipette into a cuvette in the fluorometer. On the resulting fluorescence the fluorometer output drives the pulse generator to dispense chelating agent and to operate a counter until a selected end point is reached. The pipette is then returned to its second position with the buret drive again operated by the oscillator and during the return, the buret is refilled. Both before the sample volume is aspirated, and before that volume is discharged, backlash is removed from the buret drive.

US Patent:

58142770, Sep 29, 1998

Filed:

Jan 27, 1997

Appl. No.:

8/788213

Inventors:

Charles A. Bell - Weston MA
Warren J. Heath - Marlboro MA
Norman M. Kleinman - Farmingham MA

Assignee:

Precision Systems, Inc. - Natick MA

International Classification:

G01N 3510

US Classification:

422 67

Abstract:

An analyzer for chemical assays includes a turntable which supports sample containers and reagent containers within a cooled volume and test cells about the periphery of the cooled volume. A probe is carried by a rotating arm for withdrawing liquid from the containers and dispensing the liquid. Fixed stations are also provided in the path of the probe. One such station serves to both wash the tip of the probe and to receive samples for flow-through analysis. Heaters associated with the probe and with the test cells increase the rate of reaction. Curved walls of test cell segments match the optics of an optical analyzer so that light from the analyzer lamp is generally orthogonal to the curved surfaces. The light voltage of the lamp may be controlled as a function of lamp wavelength required for particular assays. The system provides multiple-point calibration and automatic dilution of samples.

US Patent:

55977332, Jan 28, 1997

Filed:

Mar 14, 1995

Appl. No.:

8/404168

Inventors:

Charles A. Bell - Weston MA
Warren J. Heath - Marlboro MA
Norman M. Kleinman - Framingham MA

Assignee:

Precision Systems, Inc. - Natick MA

International Classification:

G01N 3510

US Classification:

436 54

Abstract:

An analyzer for chemical assays includes a turntable which supports sample containers and reagent containers within a cooled volume and test cells about the periphery of the cooled volume. A probe is carried by a rotating arm for withdrawing liquid from the containers and dispensing the liquid. Fixed stations are also provided in the path of the probe. One such station serves to both wash the tip of the probe and to receive samples for flow-through analysis. Heaters associated with the probe and with the test cells increase the rate of reaction. Curved walls of test cell segments match the optics of an optical analyzer so that light from the analyzer lamp is generally orthogonal to the curved surfaces. The light voltage of the lamp may be controlled as a function of lamp wavelength required for particular assays. The system provides multiple-point calibration and automatic dilution of samples.