Abstract: A leak detector and circuit interrupter for detecting the presence of a liquid in the base of a dispenser containment box and interrupting the supply of electrical power when such liquid is detected is disclosed. There is a user enableable circuit for selectively enabling the pump and an override circuit which is operable when enabled to disable the user enableable circuit. An optical liquid sensing probe is positioned near the bottom of the containment box with optical coupling to the override circuit. The optical probe is coupled to a light emitting diode, a photosensitive transistor, and includes a light path with at least one total internal reflection surface normally coupling the light emitting diode and the photosensitive transistor. The probe normally maintains the override circuit in an ineffective state, but, when the light path is interrupted by an accumulation of liquid in the bottom of the containment box, changes state thereby enabling the override circuit and disabling the pump.

Abstract: An apparatus for and method of calibrating a fluid meter having an output transformable into a series of digital pulses, where each pulse represents a certain volume of liquid through the meter that changes as a result of meter wear and/or component failure. A microprocessor controlled bidirectional prover tube having a calibrated volume is provided in the dispenser housing for operation once during each of a predetermined number of dispensing events. The digital pulses are accumulated during dispensation of the calibrated volume of fluid through the prover, and a calibration factor is automatically calculated and applied to the digital pulses prior to being supplied to an electronic display unit for accurate computation and display of the volume of liquid through the meter. A four-port, two-position valve is actuated prior to the beginning of each dispensing event by the microprocessor to reverse flow through the prover tube.

Abstract: A batch controller for automatically and selectively controlling a plurality of material dispensers. The controller includes circuitry for metering, for slowing, and for terminating the flow of material in and at selectable quantity levels thereof. The apparatus includes a starting circuit that renders the apparatus inoperative in response to the absence or interruption of operating potential, and flow of the material is controlled by devices that provide fail-safe termination of flow in the event of failure.