Compaq Computer Corporation, Inc.

David Seitz

Halliburton Energy Services, Inc.

David P Sharp

John L Maida

Etienne M Samson

Neal Gregory Skinner

David E Seitz

Thomas L Harman

Louis J Everett

Rodney H Neumann

Charles H Lee

Thomas Cassidy

An improved system, method and apparatus for control of an instantaneous flow-through fluid heater system is disclosed. The control incorporates a logic control method providing modulation of power in small steps to a plurality of heating elements retaining responsiveness to closed-loop control needs without inducing light flicker. Further, the life of the coils of heating circuit electromechanical relays are extended by energizing the coils with a pulse-width-modulated drive decreasing in duty cycle and thus the latent coil heat when an increase in mains voltage is sensed. The life of the contacts of same relays are extended by inhibiting heating element triac drive immediately upon sensing loss of relay coil power, such as by an over temperature limit switch opening, thus ensuring that relay contacts open with zero heating element current. In addition to the software &ldquo;watchdog timer&rdquo; internal to the microcontroller, a redundant fail-safe circuit external to the microcontroller prevents a program lockup condition from leaving any heating element triac or relay drive in an energized state. A combination of control hardware and program provide self-diagnostic detection of an inoperative thermistor, stuck relay, or a failed triac or heating element. An improved means of sensing water level is disclosed incorporating a low-level, high frequency signal, allowing detection of non-conducting distilled water and the reliable detection of water in the presence of main-frequency currents as would exist in ungrounded sheathed heating elements with electrical leakage or as would exist with bare-elements.

Fluid heating control system

A circuit board for use with two different interface standards of different computer systems. The circuit board contains interfaces to two or more different standards so that one board can be inserted into two different mother boards. The interface on the board can be card edges for edge connectors, pin and socket connectors or others. The circuit board also includes provisions for the mounting of appropriate end plates. The circuit board further includes circuitry for selecting the appropriate circuitry configuration for the active interface standard, either automatically or based on a manual selection.

Multiple computer interface circuit board

Apparatus and method for forming an integral structure, such as a lens, on a fiber, such as an optical fiber, which includes a device which imparts centrifugal force to an end of the fiber while the end of the fiber is being heated. An arc or heat source which heats the end of the fiber can both rotate about the longitudinal axis of the fiber and move laterally with respect to the longitudinal axis of the fiber. The apparatus also includes a device for longitudinally moving the fiber relative to the arc. When a fiber is inserted into the apparatus, centrifugal force is exerted on the end of the fiber as the fiber is heated. The fiber is advanced longitudinally relative to the arc until a sphere of a predetermined size is formed. Then, depending upon the shape or lens desired, the sphere may be allowed to cool and be removed from the apparatus, or other operations are performed.

Apparatus for and method of forming integral lenses on optical fibers

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Houston, TX, United States of America

David P Sharp