Abstract: A fluid overfill probe is resistant to failure caused by physical stresses resulting from thermal expansion of probe components. A fluid level detector is connected to circuit components that are mounted on a circuit board located in a housing of the probe. The circuit board is located within a tube that is positioned within, and secured to the housing, and the circuit board is secured to an inner surface of the tube along its edges. The tube has a shape and rigidity sufficient to maintain a gap between the circuit components and the inner surface of the tube such that thermal expansion of probe components result in no physical stress to the circuit components.

Abstract: A high-reliability, high-temperature liquid level detection probe uses a metal ring to hold a level detection prism in the probe body. The metal ring forms an interference fit with both the prism and the probe body and the metal/prism and metal/metal seals remain effective even at elevated temperatures so that contamination of the probe electronics is prevented. The probe electronics and the circuit board on which the electronics are mounted are enclosed in a holder so that the potting compound which is used to seal the electrical wires entering the probe does not contact the electronics or the circuit board. Thus, the circuit board and electronics are free to move in response to expansion and contraction of the potting compound and damage to the electronics and circuit board is prevented.

Abstract: In an improved electrical socket assembly a socket ring and contact block assembly are affixed to a faceplate by two snap rings. An outer snap ring fits into a groove cut into the outer end of the contact block. This snap ring bears against a shoulder on the inner surface of the socket ring and prevents the contact block from being pushed through the socket ring. The contact block extends through socket ring and further through the face plate where it is secured by an inner snap ring that bears against the inner surface of the face plate. The socket ring and the contact block are thus affixed to the face plate without using any bolts which can corrode and make replacement of the socket ring difficult.

Abstract: A cable connector has male and female connector portions that slide together in a mating direction. The housing of one connector portion has a shoulder with a surface roughly perpendicular to the mating direction. The other connector portion has a resilient retainer spring attached thereto which extends parallel to the mating direction. When the connector portions are mated, the retainer spring has a finger which slips over the shoulder surface and is held in position by the resilience of the spring to provide a retention force that resists a separation of the male and female connector portions. However, the finger is shaped and resilience of the retainer spring is such that the finger will slip off the shoulder surface upon application of a sufficiently large separation force so that separation of the connector portions may occur without damage.

Abstract: A cable connector has male and female connector portions that slide together in a mating direction. The housing of one connector portion has a shoulder with a surface roughly perpendicular to the mating direction. The other connector portion has a resilient retainer spring attached thereto which extends parallel to the mating direction. When the connector portions are mated, the retainer spring has a finger which slips over the shoulder surface and is held in position by the resilience of the spring to provide a retention force that resists a separation of the male and female connector portions. However, the finger is shaped and resilience of the retainer spring is such that the finger will slip off the shoulder surface upon application of a sufficiently large separation force so that separation of the connector portions may occur without damage.

Abstract: An optically-based overfill detection probe is provided that has a prism made of a fluoropolymer, preferably TEFLON® PFA. The prism material has a high resistance to chemical solvents, is less prone to condensation and frost than plastic or glass, and enables the production of prisms at significantly less cost than glass. The probe also includes a two-piece housing structure that compresses an outwardly-extending portion of the prism material to firmly hold the prism in place, and forces the material into sealing contact with an inner surface of the housing. The housing has an elongate portion that encompasses the prism, and which extends toward the fluid, preventing any light which escapes the prism from being externally reflected back to the photodetector of the probe.

Abstract: An optically-based overfill detection probe is provided that has a prism made of a fluoropolymer, preferably TEFLON® PFA. The prism material has a high resistance to chemical solvents, is less prone to condensation and frost than plastic or glass, and enables the production of prisms at significantly less cost than glass. The probe also includes a two-piece housing structure that compresses an outwardly-extending portion of the prism material to firmly hold the prism in place, and forces the material into sealing contact with an inner surface of the housing. The housing has an elongate portion that encompasses the prism, and which extends toward the fluid, preventing any light which escapes the prism from being externally reflected back to the photodetector of the probe.

Abstract: A fluid transfer nozzle for fuel oil and other fluid products allows for the one step removal of locking caps for vertical filling pipes. The locking cap includes a detent mechanism that, under the force of gravity, engages an obstruction within an input port of the pipe, preventing its rotation and therefore its removal. The nozzle has a socket within its mouth that engages the cap to allow rotation of the cap with rotation of the nozzle. Also within the nozzle mouth is a magnetic element that generates a magnetic field to draw the detent mechanism into an unlocked position against the force of gravity. With the cap so unlocked, the nozzle may be rotated to loosen the cap and allow its removal.

Abstract: An optically-based overfill detection probe is provided that has a prism with a substantially quadrilateral cross-sectional shape, such that internal reflection angles are less than ninety degrees. The prism is made of a fluoropolymer, preferably TEFLON® PFA, and uses an infrared optical signal. The prism material has a high resistance to chemical solvents, has high signal transmission in the infrared (IR) wavelength range, is less prone to condensation and frost than plastic or glass, and enables the production of prisms at significantly less cost than glass. The substantially quadrilateral cross-sectional shape of the prism, in itself, has the advantage of allowing angles of incidence much less than ninety degrees on internal prism surfaces, thus reducing signal loss from surface irregularities.

Abstract: A optically-based fluid overfill prevention probe has an anti-reflective guard which prevents light external to a prism of the probe from reaching a photodetector of the probe. The probe has a light source which couples light into a prism that is detected by a photodetector when it is internally reflected within the prism. When the prism is contacted by fluid in a container being monitored, the light from the light source exits the prism, and is no longer detected by the photodetector. To avoid the light exiting the prism from being accidentally reflected back into the prism in a direction which would allow it to be detected by the photodetector, the anti-reflective guard is located within a viewing radius of the photodetector, and blocks light external to the prism which might otherwise be detected by the photodetector.

Abstract: A fail-safe fluid transfer control apparatus has full redundancy in the response to various inputs such as overfill probe signals, ground detection signals, and the like. Independent microprocessor controllers independently evaluate the inputs and each output control signals to close a respective relay when the inputs indicate that fluid transfer may commence. The relays are arranged in series such that both must be closed for a fluid transfer to commence. The control signals from each controller include a static signal and an alternating signal, both of which must be properly output to close its respective relay. Each controller monitors the state of each relay, and discontinues its control signals if either relay appears to be malfunctioning. Each controller runs an different, independently written firmware program to process the detected inputs to prevent a common firmware error.

Abstract: A fail-safe fluid transfer control apparatus has full redundancy in the response to various inputs such as overfill probe signals, ground detection signals, and the like. Independent microprocessor controllers independently evaluate the inputs and each output control signals to close a respective relay when the inputs indicate that fluid transfer may commence. The relays are arranged in series such that both must be closed for a fluid transfer to commence. The control signals from each controller include a static signal and an alternating signal, both of which must be properly output to close its respective relay. Each controller monitors the state of each relay, and discontinues its control signals if either relay appears to be malfunctioning. Each controller runs an different, independently written firmware program to process the detected inputs to prevent a common firmware error.

Abstract: A fail-safe fluid transfer control apparatus has full redundancy in the response to various inputs such as overfill probe signals, ground detection signals, and the like. Independent microprocessor controllers independently evaluate the inputs and each output control signals to close a respective relay when the inputs indicate that fluid transfer may commence. The relays are arranged in series such that both must be closed for a fluid transfer to commence. The control signals from each controller include a static signal and an alternating signal, both of which must be properly output to close its respective relay. Each controller monitors the state of each relay, and discontinues its control signals if either relay appears to be malfunctioning. Each controller runs an different, independently written firmware program to process the detected inputs to prevent a common firmware error.

Abstract: A locking valve for controlling fluid flow within a conduit has a spring-biased detent in fluid communication with a fluid source. A movable valve structure prevents fluid flow through the conduit in a closed position and enables fluid flow through the conduit in an open position. Movement of the valve structure from the closed position to the open position is obstructed by the detent when fluid pressure in the conduit is below a predetermined pressure. An increase in fluid pressure, however, moves the detent against the spring bias, removing the obstruction to movement of the valve structure, and allowing the valve structure to be moved to the open position. Thus, accidental or intentional drainage of the conduit when the fluid pressure source is inactive is avoided.

Abstract: A remote level sensor for a residential fuel oil tank is adapted for a fuel oil gauge with a permanent magnet which changes position with changing fluid levels in the tank. The sensor has a housing with a connector which receives a top portion of the gauge such as to provide an alignment of the sensor with the gauge. The sensor is connected to a telephone line, and makes use of a current from the "tip" and "ring" lines of the telephone connection to supplement the power of an on-board battery. The sensor has multiple reed switches each in a different relative position. The reed switches thus each close when the magnet is in a different position, and thereby close when the fluid in the tank is at a different level. The controller has a sampling routine which responds to the detection of a closure of one of the switches by seizing the telephone line, dialing a central monitoring location and transmitting information to the central location indicating which of the switches was closed.

Abstract: A unique vehicle ID number and other verification information is stored in a small memory mounted on a tank truck. When the truck is connected to a loading terminal by means of a cable which is used by an existing overfill/ground system, an interface circuit connected between the memory and the cable prevents signals which are normally found on the cable leads from damaging the memory circuits. When information must be read from the memory, a special identification and verification system connected to the overfill/grounding circuits modifies some of the normal signals on the cable in order to activate the on-board memory and retrieve the stored information without disabling the overfill and ground proving capabilities.

Abstract: A fluid overfill and identification system uses a pulsed signal to both detect an overfill condition and identify a fluid product contained in a compartment. The pulsed signal is converted into an optical pulsed signal which is used with a retroreflective prism to detect when a fluid in the compartment has reached a desired capacity. Encoded in the pulse width of the same pulsed signal is the specific fluid product located in the compartment. Furthermore, different pulse frequencies are provided depending on whether the tanker truck is at a service station or at a loading terminal, thus allowing the system to distinguish between the two. At a marketing terminal, a new code is loaded into the system as a new fluid product is loaded into a compartment. A residue sensor may detect residual fluid in the compartment, and prevent the loading of a new fluid product and a new ID code.

Abstract: The present invention resides in a probe excitation and testing ("PET") system that can apply either a normal excitation or a "small" bias test excitation to overfill protection probes mounted within storage and transport tanks used to store, e.g., flammable fluids. The PET system applies the normal excitation for normal operation of the probes to provide overfill protection, and applies a "small" bias test excitation to the probes for performing diagnostic tests, including anti-cheating. The PET system can also perform a probe signature validation test under normal excitation to ascertain whether the probes are responding thereto in accordance with specifications relating to characteristic parameters of the probes' output waveforms, e.g., duty cycle, magnitude, and period.

Abstract: A fail safe output stage for a tank fluid level detection circuit having power supply/output leads periodically places a shunt across the leads to periodically generate a LOW signal which alternates with a HIGH signal to indicate an underfilled condition. In a filled condition, a steady signal appears across the leads. The output stage of the detection circuit consists of a parallel connection of switching devices where the "on" impedance of any single switching device is insufficient to place the detection circuit output lead in a LOW logic state. Therefore, in a condition where one of the switching devices fails, the detection circuit output may continue to alternate, but the alternating output is not recognized as such by a disable circuit which does not detect a LOW logic condition on the output lead. Accordingly, the failed output is interpreted as an filled condition, resulting in a shutdown of the system.