Abstract: A non-invasive liquid level sensor assembly includes a pair of conductive band electrodes oriented in parallel, narrowly spaced relationship and disposed so that the gap between the electrodes corresponds to the liquid surface level to be detected. The electrodes are secured to the outer surface of a liquid container, and connected to a capacitive detector device which measures the change in electrical capacity between the conductors as the liquid rises or falls past the level of the gap between the electrodes. A shield electrode is also provided, disposed outwardly of and concavely about the sensing electrodes to eliminate sensitivity to masses outside of the container. In one embodiment the electrodes are secured with a sealed, arcuate housing which is adapted to be permanently or temporarily secured to the exterior of a liquid container by adhesive, removable straps, or the like.

Abstract: In the field of automated guided vehicles it is particularly important that speed and steering angle feedbacks be accurate and reliable. Any deviations in these feedback signals should be promptly detected and used to alter operation of the vehicle. An apparatus constantly monitors the time varying output signals of a pair of resolvers respectively associated with wheel rotation and steering angle. The loss of either of the resolver signals for more than a preselected duration of time related to the excitation frequency and vehicle speed results in the power delivered to an electric drive motor being discontinued and the vehicle brakes being applied.

Abstract: A thermocouple jacket monitor is disclosed. The thermocouple monitor is constructed utilizing an inner jacket and an outer jacket with a replaceable conductive metal strip sandwiched between the inner jacket and a central insulator housing the thermocouple junctions. The conductive metal strip is connected to an alarm circuit in the thermocouple head. When the outer and inner jackets are corroded away by a molten material, such as molten glass, exposing the conductive metal strip to the molten material, the alarm such as a light on the thermocouple head, or the control panel or both, is lit notifying the operator that the thermocouple is damaged and needs to be replaced. If a two-way continuity alarm circuit is utilized, a second alarm light is activated when any portion of the conductive metal strip is corroded to the extent of being separated.

Abstract: A portable monitoring system for detecting a radiated electrostatic field and producing an audible warning when the detected field exceeds a selected value is characterized by a switching device which can be used to reset the threshold warning level and which is not affected by the hand proximity effect. An alarm is sounded when a signal corresponding to the detected field exceeds a value which is stored. The stored value can be reset by a manually operated switching circuit including a delay device operable to delay the storage of a reference level corresponding to the intensity of the field currently detected.