Patent ID: 7292945

Claim:
A fluid flow measuring and proportional fluid flow control device comprising: a proportional flow valve having a fluid inlet and a fluid outlet; an actuator for said proportional flow valve; a restrictive flow element having a restrictive flow element fluid inlet and a restrictive flow element fluid outlet in fluid communication with said fluid inlet of said proportional flow valve, said restrictive flow element creating a pressure drop between said restrictive flow element fluid inlet and restrictive flow element fluid outlet; means for measuring said pressure drop; a controller in connection with said means for measuring said pressure drop and said actuator, the controller operable to: calculate a flow rate based on said pressure drop; apply fuzzy logic rules to a change in flow rate over time (dF/dt) and a flow rate error; and determine how much to modulate said proportional fluid flow valve based on the application of fuzzy logic rules to the change in flow rate and flow rate error.