Eaton Corporation

Robert A Bauer

Richard Walter Hirthe

Martin Arthur Seitz

Mark H Polczynski

James E Hansen

Paul G Rops

A plug for insertion through the wall of a vessel filled with fluid to be monitored has an extension immersed in the fluid which has a pair of wire electrodes helically wound thereon in spaced arrangement. The electrodes are wound at a uniform pitch in one embodiment and wound with regions of closely and widely spaced pitches in another embodiment. In a third embodiment, the electrodes are helically wound in spaced parallel arrangement at a pitch greater than the spacing of the pair. A thermistor is disposed on the extension for providing a fluid temperature signal. The electrodes are excited sequentially by a low voltage at a fractional Hertz (low) frequency and a (high) frequency of at least one Hertz and the current and temperature are measured. The impedance and differential impedance are computed from the measured currents. From stored values of the differential impedance as a function of temperature for various known fluid conditions, the condition of the fluid is determined; and, if greater than a predetermined threshold, an alarm is activated and/or the fluid condition displayed.

Monitoring fluid condition with a spiral electrode configuration

A fluid condition monitor suitable for real time monitoring of a fluid in a fluid system such as on-board vehicle monitoring of engine oil and transmission fluid to determine contamination. A capacitive spaced array electrode probe is immersed in the fluid and an oscillating voltage is applied at a first frequency of at least one hertz and the current I,measured as an analog of the bulk fluid impedance. The voltage is also applied to the probe at a second frequency of less then one hertz and the current I,measured as an analog of the electrode surface impedance. The difference in measured currents &Dgr;I is determined electrically compared with a predetermined threshold value; and, the measured first frequency current I,is compared with an upper and lower limit value for I,determined empirically for the known baseline fluid. If &Dgr;I is below the threshold or I,is not within the upper and lower limits, a fault condition is declared and an indicator is activated to warn that the fluid is not suitable for continued operation of the system. An alternate embodiment includes a fluid level sensor.

Growing community of inventors

Milwaukee, WI, United States of America

Robert A Bauer