Donald Jay Stephens

US Patent:

44380704, Mar 20, 1984

Filed:

Dec 4, 1981

Appl. No.:

6/327379

Inventors:

Donald E. Stephens - Palo Alto CA
Thomas D. Sharples - Atherton CA

Assignee:

Beckman Instruments, Inc. - Fullerton CA

International Classification:

G01N 3108

US Classification:

422 70

Abstract:

An elongate straight column for use as a reactor in an analytical instrument. The column contains inert packed material which provides for the necessary flow path length for a fluid stream entering the reactor. Fittings are incorporated onto the ends of the column in such a manner that their width is no larger than the width of the column. The column configuration for a reactor allows more versatility in the type of temperature regulator mechanisms used to heat and cool the reactor.

US Patent:

42947995, Oct 13, 1981

Filed:

Apr 24, 1980

Appl. No.:

6/143212

Inventors:

Donald E. Stephens - Palo Alto CA
John T. Taylor - Santa Clara CA

Assignee:

Beckman Instruments, Inc. - Fullerton CA

International Classification:

G01N 3122
G01N 3108
G01J 346

US Classification:

422 62

Abstract:

A temperature regulating apparatus which increases optical sensitivity and resolution of a liquid in a reaction chamber by heating while providing rapid cooling to prevent vaporization of the liquid within the reaction chamber. The apparatus includes a heat exchanger containing the reaction chamber and an insulating chamber surrounding the heat exchanger. A coolant may be passed through the heat exchanger to prevent boiling should a change in liquid flow make such occurrence likely. The change in liquid flow is monitored by an analyzer monitor, and the temperature in the reaction chamber is changed accordingly.

US Patent:

45349410, Aug 13, 1985

Filed:

Dec 4, 1981

Appl. No.:

6/327372

Inventors:

Donald E. Stephens - Palo Alto CA
Robert J. Ehret - Los Altos CA

Assignee:

Beckman Instruments, Inc. - Fullerton CA

International Classification:

G01N 3108

US Classification:

422 70

Abstract:

A temperature control system used to precisely and accurately control the temperature of a fluid stream in an analytical system designed for investigation of the chemical constituents of the fluid stream. One example of use is in chromatography such as for the chromatographic column in an amino acid analyzer system. The temperature control system utilizes a set of thermoelectric modules to transfer heat between a thermoconductive block which holds the chromatographic column and an air exchange heat sink which obtains heat from or disposes heat into ambient air as required. The control system regulates the temperature at a very rapid rate in order to minimize the recycle time of the instrument.

US Patent:

43721508, Feb 8, 1983

Filed:

Jun 5, 1980

Appl. No.:

6/156718

Inventors:

Donald E. Stephens - Palo Alto CA
Robert J. Ehret - Los Altos CA

Assignee:

Beckman Instruments, Inc. - Fullerton CA

International Classification:

G01M 328

US Classification:

73 405R

Abstract:

A method and apparatus for monitoring flow rate through a conduit. A flow number indicative of the flow rate of a liquid through the conduit is compared with a preselected reference number. The actual liquid flow through the conduit provides a clocking signal which determines the time span during which a count signal, indicative of the intended flow rate into the conduit, is accumulated thereby providing the flow number.

US Patent:

45187002, May 21, 1985

Filed:

Dec 4, 1981

Appl. No.:

6/327378

Inventors:

Donald E. Stephens - Palo Alto CA

Assignee:

Beckman Instruments, Inc. - Fullerton CA

International Classification:

G01N 3108

US Classification:

436 52

Abstract:

A temperature control apparatus for a high temperature reactor in an analytical instrument of the type in which a development reagent is added to a flowing stream as part of the detection process. The temperature control apparatus utilizes solid state heat transfer means to transfer heat between a thermoconductive block to which is mounted the reactor and an air exchange heat sink which obtains heat from or disposes heat into ambient air as required. The control apparatus regulates the temperature of the reactor at a very rapid rate in the high temperature range of approximately 90. degree. C. to 150. degree. C. without the use of a separately contained heat exchange medium. The ability of the apparatus to cool the reactor rapidly eliminates the requirement to keep reactor contents at elevated pressures to prevent vaporization of the stream being analyzed.

US Patent:

49267027, May 22, 1990

Filed:

Sep 18, 1987

Appl. No.:

7/098573

Inventors:

Donald E. Stephens - Palo Alto CA
Manfred W. Unterbusch - Sunnyvale CA

Assignee:

Beckman Instruments, Inc. - Fullerton CA

International Classification:

G01N 114

US Classification:

7386483

Abstract:

A detector for detecting the presence of an electrically conductive sample solution in a sample injection metering valve by electrical sensing the leading edge of the sample solution, wherein the amount of sample solution in excess of the metered amount required to cause detection is minimized. A conductive probe is positioned on the valve body just downstream of the sample metering passage of the valve, the probe being electrically insulated from the valve body. The probe and valve body form electrodes which will detect the arrival of the leading edge of a conductive sample solution which completes a conductive circuit between the electrodes.