Patent ID: 7225664

Claim:
A system for detecting a leak in a double-walled fuel piping having an outer annular space that carries fuel from an underground storage tank in a service station environment, comprising: a pressure sensor that is coupled to the outer annular space to detect a vacuum level in the outer annular space; a sensing unit controller that is coupled to said pressure sensor to determine the vacuum level in the outer annular space; a submersible turbine pump that is fluidly coupled to the fuel in the underground storage tank to draw the fuel out of the underground storage tank wherein said submersible turbine pump is also coupled to the outer annular space; said submersible turbine pump creates a vacuum level in the outer annular space wherein said sensing unit controller determines the vacuum level in the outer annular space using said pressure sensor; a controller that is electrically coupled to said submersible turbine pump wherein said submersible turbine pump creates a defined initial threshold vacuum level in the outer annular space after receiving a test initiation signal from the controller, wherein the controller is electrically coupled to said sensing unit controller to receive the vacuum level in the outer annular space; and a float liquid detection sensor that is coupled to the outer annular space, wherein said float liquid detection sensor is coupled to said sensing unit controller and wherein said float liquid detection sensor detects if liquid is present in the outer annular space.