Fueling system vapor recovery and containment performance monitor and method of operation thereof

A system for monitoring vapor recovery in a liquid fuel dispensing facility having at least two fuel dispensing points connected to a main fuel storage system by a vapor return pipeline, said monitoring system comprising:

• a vapor flow sensor operatively connected to the vapor return pipeline;
• means for determining dispensed liquid fuel amount information for each fuel dispensing point;
• and
• a means for determining a ratio of vapor flow to dispensed liquid fuel for the fuel dispensing points based on vapor flow sensor readings and dispensed liquid fuel amount information,
• wherein the acceptability of vapor recovery for the fuel dispensing points is determined by said ratio of vapor flow to dispensed liquid fuel.

A method of monitoring vapor recovery in a liquid fuel dispensing facility having at least one fuel dispensing point connected to a main fuel storage system by a means for supplying liquid fuel to the dispensing point and a means for returning vapors from the dispensing point, said monitoring method comprising the steps of:

• determining at multiple times an amount of vapor flow through the means for returning vapors;
• determining at multiple times an amount of liquid fuel dispensed through the means for supplying liquid fuel;
• and
• determining a ratio of vapor flow to dispensed liquid fuel for the fuel dispensing point based on the amount of vapor flow through the means for returning vapors and the amount of liquid fuel dispensed through the means for supplying liquid fuel,
• wherein the acceptability of vapor recovery for the fuel dispensing point is determined by said ratio of vapor flow to dispensed liquid fuel.

A system for monitoring vapor containment in a liquid fuel dispensing facility having a main fuel storage system connected by a vent pipe-pressure relief valve arrangement to atmosphere, said monitoring system comprising:

• a pressure sensor operatively connected to the vent pipe;
• a vapor processor operatively connected to the vent pipe;
• and
• means for determining the acceptability of vapor containment in the main fuel storage system, said determining means being operatively connected to the pressure sensor to receive pressure level information therefrom and being operatively connected to the vapor processor to selectively cause the vapor processor to draw a negative pressure in the main fuel storage system.

A method of monitoring vapor containment in a liquid fuel dispensing facility having at least one main fuel storage tank connected by a vent pipe-pressure relief valve arrangement to atmosphere, said monitoring method comprising the steps of:

• identifying the start of an idle period for the liquid fuel dispensing facility;
• monitoring the liquid fuel dispensing facility to confirm maintenance of the idle period;
• determining whether pressure in the main fuel storage tank is equal or below a minimum level;
• selectively adjusting pressure in the main fuel storage tank to a preset lower level when the previously determined pressure is above the minimum level;
• monitoring variation of the pressure in the main fuel storage tank during the remainder of the idle period;
• determining the end of the idle period;
• and
• determining the acceptability of vapor containment in the main fuel storage tank based on the variation of the pressure during the idle period.

A method of determining vapor recovery system failures associated with a single fuel dispensing point, said method comprising the steps of:

• determining the vapor flow to dispensed fuel ratios for a plurality of fuel dispensing points;
• determining the number of vapor flow to dispensed fuel ratios that are below a preset minimum for each of the plurality of fuel dispensing points;
• determining the average number of vapor flow to dispensed fuel ratios below the preset minimum for the plurality of fuel dispensing points;
• and
• comparing the number vapor flow to dispensed fuel ratios below the preset minimum for each of the plurality of fuel dispensing points to the average number of vapor flow to dispensed fuel ratios below the present minimum to determine whether the vapor recovery system associated with each of the plurality of fuel dispensing points has failed.