초록 ▼

A leak detection system which operates at relatively high pressures and senses relatively large pressure drops to monitor for leakage in fuel product lines such as those used for dispensing of fuel at gasoline service stations. Leakage tests of various degrees of precision are carried out, and the p

A leak detection system which operates at relatively high pressures and senses relatively large pressure drops to monitor for leakage in fuel product lines such as those used for dispensing of fuel at gasoline service stations. Leakage tests of various degrees of precision are carried out, and the possible effects of thermally induced expansion and contraction are taken into account. The system also checks for faulty pressure sensors and dry tank conditions. Leak indications are confirmed by a time delay and retesting before a leak alarm is given.

대표청구항 ▼

In a leak detection apparatus for a fuel product line through which fuel is pumped by a pump for dispensing, the improvement comprising: means for sensing a preselected pressure in the product line that is approximately 15 psi below a relief pressure at which the product line is normally maintained

In a leak detection apparatus for a fuel product line through which fuel is pumped by a pump for dispensing, the improvement comprising: means for sensing a preselected pressure in the product line that is approximately 15 psi below a relief pressure at which the product line is normally maintained when fuel is not being pumped therethrough; means for declaring a passed hourly test if said preselected pressure in the product line is not sensed within a first time duration; means for declaring a passed monthly test if said preselected pressure in the product line is not sensed within a second time duration longer than said first duration; means for declaring a passed annual test if said preselected pressure in the product line is not sensed within a third time duration longer than said second duration; means for sensing the presence of thermally induced expansion in the product line; means for overriding all of said declaring means and effecting a thermal expansion test mode when thermally induced expansion is present; means when in the thermal expansion test mode for declaring a passed monthly test if a predetermined pressure higher than said preselected pressure but below the relief pressure is not sensed within a fourth time duration longer than said second duration; and means when in the thermal expansion mode for declaring a passed annual test if a predetermined pressure higher than said preselected pressure but below the relief pressure is not sensed within a fifth time duration longer than said third duration.