Gasoline dispenser with enhanced vapor recovery system

摘要

A service station dispenser for gasoline with a vapor collection system is disclosed which processes the electrical signal typically produced by the fuel meter which represents the volume flow rate of fuel to the tank to control the displacement volume of an electrically driven vacuum pump so that a simple vacuum intake disposed preferably inside, but not sealed with, the filler neck can be used to collect only the vapors displaced from the fuel tank by the fuel. The vacuum pump is controlled by a digital processor which prestarts the vacuum pump after a customer demands dispensing to establish a vacuum at the vacuum intake is established by the time fueling is allowed to take place so as have an immediate vacuum available to assist recovery of an initial rush of vapor displaced by commencement of fueling. Once fuel flow starts, the digital processor operates the vacuum pump to produce a vapor flow rate having a proportional relationship with the flow rate of the fuel.