Abstract: A microprocessor controlled timer is installed in a petroleum service station product dispensing system that includes a pump relay, a pump, a dispenser, and a leak detection monitor. The timer activates pump relays to pressurize a liquid product line that runs from a tank to the dispenser at predetermined intervals to compensate for thermal contraction during product line leakage testing. Prior to activating pump relays, the timer has circuitry to determines if product is currently being dispensed. If product is being dispensed, the timer waits until dispensing has halted before activating pump relays to pressurize the product line. Also prior to activating pump relays, the timer has circuitry to determine if pump operation should be inhibited and if so halts before activating pump relays. Optical isolation is used between the timer and pump relays and a dispenser switch.

Abstract: A fluid detection system includes a central monitor, an overfill probe for detecting the approach of the overfill condition of a tank of liquid, and n other probes, where n is an integer greater than or equal to 1. The probes are connected to the monitor via electronic cables. The monitor communicates with the probes by producing probe identifier signals comprising integers starting with zero up to the number n. Each probe includes a signal receiving and sending means which compares the identifier signal sent by the monitor to a preset identifier number for that probe and sends a status signal indicative of the fluid status at that probe when it receives the identifier signal that is the same as the preset number. The overfill probe is set with the identifier zero. The monitor includes a timing circuit which determines a six second probe check cycle.

Abstract: A strip of resistive carbon is deposited on a longitudinal plastic film and a strip of conductive copper is deposited on a second film. The two film strips are glued together with the resistive and conductive strips opposing to form a sealed envelope having a longitudinal cavity. This sandwich is placed in a flexible extruded tube membrane and the whole inserted in a longitudinal slot in a frame, with a channel communicating with the slot and the exterior of the frame. Liquid in a tank compresses the envelope, causing the copper and carbon strips to contract at a point depending on the level. The change in resistance of the carbon-copper circuit with level produces a changing voltage which is processed to provide a signal indicative of the level of in the tank. Temperature sensors in the frame provide the temperature of the at various levels.

Abstract: A controller including a digital processor is connected to flow meters and overfill gauges suitable for placement in the fill ports of underground storage tanks at, for example, a gasoline service station. The station dispenser pumps are also connected to the controller. In addition, probes, including tank liquid level probes, line pressure probes, and leak probes capable of detecting small quantities of liquid leaking from the system, are also connected to the controller. Processor software programs use stored decision criteria relating liquid conditions external of the storage tank system and liquid conditions internal of the storage tank system and its contents to provide audio and visual indications of the status of the liquid storage system and its contents.

Abstract: There is a controller connected to a plurality of probes via a transmission line. The controller provides a command signal including a probe identifier signal and a probe data signal. Each probe includes a plurality of different sensors, each providing one or more status signals on a plurality of probe data channels. Each probe also includes a comparator for comparing the probe identifier signal to a local probe address, a multiplexer responsive to the data signal for selecting one of the data channels, and a switch responsive to the comparator to provide the selected data signal to the controller when the identifier signal correlates with the local probe address.

Abstract: An apparatus for sensing the difference between a polar fluid and a non-polar fluid includes a control assembly, a probe assembly and a conduit electrically coupling the probe assembly to the control assembly at a remote location thereto. The probe assembly includes a float, at least one fluid sensor mounted beneath the float, a fluid sensor circuit for providing a signal indicative of the polar characteristics of the fluid, and a logic circuit having a first state when the signal indicates a polar fluid and a second state when the signal indicates a non-polar fluid. The control assembly includes cicuitry responsive to the state of the logic circuit for controlling alarms, visual indicators, and machine operations. The probe assembly may also include a detector for detecting the state of the fluid. If the fluid has a non-liquid state then the logic circuit has a third state which indicates the non-liquid state of the fluid.

Abstract: There is a plurality of probes electrically connected to a central controller. Each of the probes is capable of providing a hydrocarbon signal, a water signal and a dry signal upon sensing these respective environments. The controller includes an audible alarm transducer and a switch for activating circuitry providing either a first alarm mode which provides an alarm in response to a hydrocarbon signal or a second alarm mode which provides an alarm in response to a hydrocarbon signal and also a water signal. A continuous alarm tone is provided upon receiving a hydrocarbon signal while an intermittent alarm tone is provided upon receiving a water signal. A yellow label links a "water" sign and the transducer and a red label links an "oil" sign and the transducer.

Abstract: A fluid detection system capable of displaying the conditions in the environs of a large number of fluid detection probes and correlating each condition with the particular probe that detected it. There are a plurality of probes, each having a comparator preset with a unique probe identifier, such as a binary number. A counter produces digital signals representative of the binary numbers. The probe comparators are responsive to the numbers outputted by the counter and are connected to the probe power circuitry. When each comparator receives the signal corresponding to its preset number, it triggers its associated probe to produce status signals. A display circuit responds to both the number output by the counter and the probe status signals to simultaneously display the probe number and an indication of probe status.

Abstract: An apparatus for sensing the difference between a polar fluid and a non-polar fluid includes a control assembly, a probe assembly and a conduit electrically coupling the probe assembly to the control assembly at a remote location thereto. The probe assembly includes a float, at least one fluid sensor mounted beneath the float, a fluid sensor circuit for providing a signal indicative of the polar characteristics of the fluid, and a logic circuit having a first state when the signal indicates a polar fluid and a second state when the signal indicates a non-polar fluid. The control assembly includes circuitry responsive to the state of the logic circuit for controlling alarms, visual indicators, and machine operations. The probe assembly may also include a detector for detecting the state of the fluid. If the fluid has a non-liquid state then the logic circuit has a third state which indicates the non-liquid state of the fluid.

Abstract: A float assembly for a sensor provides a float member having a channel passing therethrough, a mounting for the sensor on the float, a guide passing through the channel for guiding the movement of the float member, a stop including a magnet located on the guide for limiting the movement of the float, and a magnetically activated switch included in the float member for activating when in proximity to the stop magnet for indicating that the float member is in proximity to the stop.

Abstract: A hydrocarbon sensor float for use in detecting the presence of hydrocarbons on the surface of a liquid provides an elongated floatation member having a top end and a bottom end and also having a cavity located centrally therealong and extending completely therethrough, a sensor assembly including a sensor and at least one electrical conductor coupled to the sensor, the sensor assembly being positioned in said floatation member for locating the sensor in the cavity for allowing access of the liquid thereto and for causing the electrical conductor to extend from the top end of the floatation member, and an attachment for a variable amount of weight at the bottom end of the floatation member for providing a variable floatation level for the member with respect to the liquid surface and likewise for the sensor for allowing adjustment of the detection depth for hydrocarbons at an installation site.

Abstract: A hydrocarbon responsive switch provides an elongated flexible member which is impervious to hydrocarbon substances, a hydrocarbon absorber bonded to the elongated flexible member for absorbing hydrocarbon substances in contact therewith and for swelling from the absorbing for causing the flexible member to bend, a mounting for one end of the elongated member, a first electrical contact located at the other end of the elongated member, and a second electrical contact for contacting the first contact upon bending of the elongated flexible member and thereby making electrical connection in response to the absorption of hydrocarbon substances by the absorber.

Abstract: A sensing device for detecting a substance including hydrocarbons on the surface of water provides a floatation device for floating on the water surface and for supporting at least one sensing element for detecting the hydrocarbon substance with the floatation device is composed substantially of nitrile and having printed circuitry deposited on the nitrile for providing electrical connection between the sensing element and an electrical conductor for coupling the element to a sensing instrument.