In-ground tank measuring system

Claim 1

A system for monitoring the level of liquid fuel in each of a plurality of underground tanks comprising a float resting on the surface of said liquid fuel in each of said tanks, cable means connected to each float extending vertically upwardly and out of each said tank, and transducer means including biased take-up reel means for the winding thereon of each of said cable means, each said reel means being biased to take up any slack in said cable means, and potentiometer means having a wiper coupled to said reel means for indicating the level of said liquid fuel in each said tank, and monitor means connected by electrical cable means to all of said potentiometer means for displaying in digital form the level of fuel in a selected tank and a warning when a predetermined level is reached in any one of said tanks, said monitor means comprising means to generate a reference voltage and apply same across each of said potentiometer means, means to receive the voltage signals picked off by each wiper, each of said signals being a direct indication of the level of fuel in each of said tanks, switch means to select one of said voltage signals, means for converting the selected voltage signal into the aforesaid digital readout display for indicating directly and virtually instantaneously the level of fuel in the tank whose voltage signal was selected, a separate power source for said converting means, means bypassing said switch means for identifying and producing a warning signal when the level of fuel drops to a predetermined value in any one of said tanks, separate electrical grounds being provided for the reference voltage and said power source to reduce the effects of interference noise on said voltage signals, and means to adjust the reference voltage and means to adjust the tank empty and full level signals for each of the tanks.

Claim 2

A system for monitoring the level of liquid fuel in each of a plurality of underground tanks comprising a float resting on the surface of said liquid fuel in each of said tanks, cable means connected to each float extending vertically upwardly and out of each said tank, and transducer means including biased take-up reel means for the winding thereon of each of said cable means, each said reel means being biased to take up any slack in said cable means, and potentiometer means having a wiper coupled to said reel means for indicating the level of said liquid fuel in each said tank, and monitor means connected by electrical cable means to all of said potentiometer means for displaying in digital form the level of fuel in a selected tank and a warning when a predetermined level is reached in any one of said tanks, said monitor means comprising means to generate a reference voltage and apply same across each of said potentiometer means, means to receive the voltage signals picked off by each wiper, each of said signals being a direct indication of the level of fuel in each of said tanks, switch means to select one of said voltage signals, means for converting the selected voltage signal into the aforesaid digital readout display for indicating directly and virtually instantaneously the level of fuel in the tank whose voltage signal was selected, a separate power source for said converting means, means bypassing said switch means for identifying and producing a warning signal when the level of fuel drops to a predetermined value in any one of said tanks, separate electrical grounds being provided for the reference voltage and said power source to reduce the effects of interference noise on said voltage signals, and means to adjust the reference voltage and means to adjust the tank empty and full level signals for each of the tanks.