Abstract: 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.

Abstract: A method for real time monitoring fluid in a vessel with a probe having a pair of electrodes immersed in the fluid. The disclosed probe has the electrodes arranged helically on a rod, sized and configured for insertion in an engine dipstick hole. Preferably, the probe has spiral electrode winding up regions different pitch to provide improved impedance response at low fractional Hertz and high (at least one Hertz) frequencies of excitation. In one version with alternating voltage the difference in current magnitude measured at the low and high frequencies is compared with stored known values for known fluid conditions and an electrical signal indicative of fluid condition is generated. Examples with engine drain oil and heavy duty transmission lubricant fluid are presented. The impedance properties measured can determine the percentage remaining useful life (RUL) of the fluid.

Abstract: 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 IB 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 Is 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 IB is compared with an upper and lower limit value for IB determined empirically for the known baseline fluid.

Abstract: An oximeter sensor assembly (40) includes a thin elongated flexible sheet-like strip (42) having an integral end portion (44) for flexibly wrapping at least partially around a human body part (26), a plurality of electrical conductors (46-50) on the strip, light emitting and receiving electrical components (28a, 30a) mounted on the strip on the end portion and electrically connected to the conductors, and encoding means provided by a pair of auxiliary conductors (202, 204) and resistance material (206) therebetween for providing signals to the oximeter indicative of the known wavelength of the light emitting electrical component for calibrating the oximeter.

Abstract: An oximeter sensory assembly (40) includes a thin elongated flexible sheet-like strip (42) having an integral end portion (44) flexibly wrapping at least partially around a human body part (26), a plurality of electrical conductors (46-50) on the strip, and light emitting and receiving electrical components (28a, 30a) mounted on the strip on the end portion and electrically connected to the conductors. Flexible conductive encompassing shielding layers (62, 66) are also provided, together with outer insulating layers (61, 67). Connection adapter structure (94) is also provided.

Abstract: An oximeter sensor assembly (40) includes a thin elongated flexible sheet-like strip (42) having an integral end portion (44) flexibly wrapping at least partially around a human body part (26), a plurality of electrical conductors (46-50) on the strip, and light emitting and receiving electrical components (28a, 30a) mounted on the strip on the end portion and electrically connected to the conductors. Flexible conductive encompassing shielding layers (62, 66) are also provided, together with outer insulating layers (61, 67). Connection adapter structure (94) is also provided.