The Babcock & Wilcox Company

Barry J Youmans

Richard C Ciammaichella

Sharon L Zimmerlin

An oxygen sensor utilizes the paramagnetic property of oxygen to determing the relative concentration of oxygen in a test gas. The test gas is supplied to the core of an electromagnet or the gap of a permanent magnet. A known magnetic flux density for the electromagnet or permanent magnet are utilized in conjunction with a Hall effect sensor to determine a change in flux which is primarily due to the oxygen component of the test gas.

Linear Hall effect oxygen sensor with auxiliary coil magnetic field

A flame detector comprises a light collecting lens or other device for collecting electromagnetic radiation from a flame's source, a filter for passing only a portion of the electromagnetic radiation from the lens which changes from between a flame on and a flame off condition, a solid state photocell for receiving the portion of electromagnetic radiation passed by the filter, and a circuit for producing a signal indicative of whether the flame is on or off in response to a signal generated by the photocell. The photocell is preferably sensitive to ultraviolet radiation to avoid confusion with infrared radiation that is produced by heat near the flame's source and which heat is not necessarily indicative of whether the flame is on or off. Such a photocell can preferably be made of Gallium Arsenide Phosphide semiconductor material.

Solid state ultraviolet flame detector

A linearizing circuit (10) is disclosed for devices having logarithmic outputs, such as electrolytic oxygen detectors (12). The circuit (10) has an inverting biasing circuit (14) and a scaling circuit (16) connected to an antilog function generator (18) and is calibrated by zeroing the inverting biasing circuit (14) at an extreme point of the desired range and sealing a second point on the desired range in the scaling circuit (16).

Linearizing circuit and method of calibrating same

A circuit (10) that prevents a photo diode (12) from reaching its saturation output voltage thus ensuring the sensitivity of the photo diode to small changes in radiance at high radiance levels is disclosed. The circuit utilizes a transistor (30) that is allowed to conduct after the output voltage of the photo diode (12) has reached a predetermined level thus shunt loading the photo diode preventing it from reaching its saturation level. A resistor (28)-capacitor (32) time constant circuit is provided preventing the transistor (30) from conducting until the output voltage of the photo diode (12) has reached a predetermined level for a predetermined period of time thus preventing premature conduction of the transistor (30) in response to transient or spurious voltages.

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Rittman, OH, United States of America

Barry J Youmans