Pressure-based gas flow controller with dynamic self-calibration

A device for measuring a molecular rate of gas flow from a source of gas at a pressure higher than a pressure of a destination, comprising:

• an upstream valve, a cavity of known volume in fluid connection with the upstream valve, a restrictor element in fluid connection with the upstream valve via the cavity, and a control system comprising at least one of a processor or other type of programmable device, the control system being adapted to vary the flow rate of the gas through the upstream valve in a determined manner such that an average cavity pressure correlates with an average level of gas flow rate and such that cavity pressure variations induced by varying the flow rate of gas through the upstream valve in the determined manner induce instantaneous flow variations smaller than 30% of the average level of gas flow rate to the destination, wherein cavity pressure variations associated with varying the flow rate of gas through the upstream valve in the determined manner are used by the processor to determine the molecular rate of gas flow in real time.

A system comprising a flow path for a gas from a source of gas to a destination, the system comprising:

• a device in fluid connection with the flow path, the device comprising an upstream valve, a cavity of known volume in fluid connection with the upstream valve, a restrictor element in fluid connection with the upstream valve via the cavity, and a control system comprising at least one of a processor or other type of programmable device, the control system being adapted to vary a flow rate of the gas through the upstream valve in a determined manner such that an average cavity pressure correlates with an average level of gas flow rate to the destination and such that cavity pressure variations induced by varying the flow rate of gas through the upstream valve in the determined manner induce instantaneous flow variations smaller than 30% of the average level of gas flow rate to the destination, wherein cavity pressure variations associated with varying the flow rate of gas through the upstream valve in the determined manner are used by the processor to determine the molecular rate of gas flow in real time.