Abstract: A user friendly vapor recovery nozzle with special signaling devices to signal and assure the customer of proper delivery of fuel and return flow of hydrocarbon vapors. In the preferred embodiment, the signaling devices include both a fuel flow indicator and a vapor flow indicator. The flow indicators can comprise one or more fuel and vapor driven balls, paddle wheels, propellers, spinners, blades, or vanes. In the preferred form, the vapor recovery nozzle has an inner fuel spout to discharge gasoline into a customer's tank and has an outer spout which cooperates with the inner spout to provide a vapor return passageway to return vapors emitted during fueling to a vapor return hose. The nozzle has a liquid sensing tube in the vapor return passageway to sense when the customer's tank is filled. An automatic shutoff valve cooperates with the liquid sensing tube to shutoff the supply of gasoline when the customer's tank is filled.

Abstract: A reader for a coded discontinuous security thread in a security document comprises a multiplicity of reading channels each coupled to at least one magnetic transducing means (11, 40) for sensing along a track across the document and including processing circuits for forming a channel signal which exhibits signal excursions in response to the passage of the ends of each length of magnetic material. First and second comparators (55, 56) compare the channel signal with relatively positive and relatively negative thresholds respectively and a bistable switching means (59) is coupled to the comparators to provide a digital signal. A reference comparator (64) controls an analog switch and diode pumps (70, 71) to adjust the thresholds in accordance with the amplitude of a signal excursion.