Abstract: A method of determining the thermal status of fuel in a fuel distribution system (10) includes pressurizing the distribution line (16) by activating a submersible pump (14) in an underground storage tank (12). Once the distribution line (16) is pressurized, the pump (14) is switched off, and the reverse flow rate out of the distribution line back into the tank (12) is monitored. The test is repeated after a period of time, and the reverse flow rates of the separate tests are compared to determine if the fuel in the distribution line (16) is in thermal stability with the surrounding environment based on flow rate changes between tests.

Abstract: An apparatus for detecting a leak in a conduit line includes a housing in fluid communication with the line, a valve including a valve seat and a valve element movable relative to the seat between opened and closed positions, a bypass line around the valve, a flow detector coupled to the bypass line for detecting fluid flow therethrough, and a mechanism configured to urge the valve element toward the closed position and to maintain the valve element in the closed position until a threshold pressure drop is reached. The mechanism may operate on the principle of magnetism.