Patent ID: 8122918

Claim:
At a refuel depot where on board vehicle tanks are refueled from a bank of independently switched storage tanks containing high pressure fuel gas, a switching apparatus for determining which one of the depot storage tanks is activated to allow gas flow to the on board vehicle tank when gas in the storage tanks of high pressure gas at the depot utilized for refueling the on board fuel-tanks, comprising: (i) a gas flow circuit interconnecting the bank of storage tanks to an inlet of the vehicle tanks; (ii) a control valve in the gas flow circuit between the bank of storage tanks and the vehicle tank inlet; (iii) a first pressure sensor that monitors gas pressure at a depot side of the control valve, the first pressure sensor connected in advance of and proximate to the control valve with respect to the direction of gas flow; (iv) a second pressure sensor that monitors gas pressure at a vehicle side of the control valve, the second sensor connected at the vehicle side of the control valve; (v) gas flow outlet valves V 1 . . . V n , each outlet valve associated separately with each one of the storage tanks; (vi) a gas flow switching valve located a) between the gas flow outlet valves V 1 . . . V n of each depot storage tank or b) at a connection leading from at least two gas flow outlet valves V 1 . . . V n ; and (vii) a programmed control unit to control the valves comprising a pressure comparator measuring a) a first pressure at the first pressure sensor (P 1 ) and b) a second pressure at the second pressure sensor (P 2 ); wherein, when a pressure difference between the P 1 and P 2 equals approximately 0 and a desired pressure for a fill (P 3 ) has not been met, gas flow switches from a first storage tank at the depot to a next storage tank at the depot and, when the difference between P 1 and P 2 equals approximately 0, and P 3 has been met, the control valve is closed.