Patent ID: 7284564

Claim:
A gas supply system arranged for dispensing of gas at predetermined flow rate, comprising a gas source vessel and gas dispensing flow circuitry coupled to said vessel, wherein the gas dispensing flow circuitry comprises a variable size orifice device arranged for dispensing gas at variable gas flow conductance conditions during gas dispensing operation involving change in amount and pressure of gas in said gas source vessel, to maintain said predetermined flow rate of the dispensed gas in the operation of the system, wherein the gas dispensing flow circuitry is at least partially disposed in an interior volume of the gas source vessel, with the variable size orifice device being disposed in said interior volume, and a pressure sensing device disposed in said interior volume, arranged to sense pressure of the gas in said interior volume, and coupled in controlling relationship with the variable size orifice device to vary open area of its orifice in response to the sensed pressure of the gas in said interior volume.