초록 ▼

A microprocessor based system for detecting leaks from underground gasoline storage tanks and the product lines through which the gasoline is pumped to above ground dispensers. Hydrocarbon sensitive probes spaced around the tank in monitoring wells detect gasoline leakage from the tank. Each probe c

A microprocessor based system for detecting leaks from underground gasoline storage tanks and the product lines through which the gasoline is pumped to above ground dispensers. Hydrocarbon sensitive probes spaced around the tank in monitoring wells detect gasoline leakage from the tank. Each probe can be independently programmed as to the threshold hydrocarbon concentration considered to be indicative of a leak. Pressure transducers sense the product line pressure and distinguish thermally induced contraction from true leaks by comparing the time required for a preselected pressure drop to occur during successive cycles. A time comparison is also used to detect the presence of excessive air in the product line. An alarm condition sensed by either type of sensor generates audible and visible alarm signals and automatically dials a programmed telephone number. The alarm times and dates are stored in memory and may be called up on the display screen.

대표청구항 ▼

A method of detecting leakage from a product line through which liquid is pumped and in which the liquid is subject to possible thermally induced contraction, said method comprising the steps of: monitoring the pressure in the product line; measuring the time required for the produce line pressure t

A method of detecting leakage from a product line through which liquid is pumped and in which the liquid is subject to possible thermally induced contraction, said method comprising the steps of: monitoring the pressure in the product line; measuring the time required for the produce line pressure to drop from one preselected pressure level to a lower preselected pressure level during a first cycle; raising the pressure in the product line from said lower preselected pressure level to a level at least as high as said one preselected pressure level; measuring the time required for the product line pressure to drop from said one preselected pressure level to said lower preselected pressure level during a second cycle; and interpreting the drops in pressure as resulting from a leak in the product line unless the time measured during said second cycle exceeds the time measured during first cycle by a predetermined amount.