Patent ID: 7424894
Filing Date: 2008-09-16
Classification: G05D,Y10T

Abstract:
1. A fluid flow control system, comprising: a fluid inlet to receive a flow of process fluid; a first fluid outlet to provide a first predetermined portion of the flow of process fluid received at the fluid inlet; a second fluid outlet to provide a remaining portion of the flow of process fluid received at the fluid inlet; a valve having a valve inlet fluidly coupled to the fluid inlet, a first valve outlet fluidly coupled to the first fluid outlet, and a second valve outlet fluidly coupled to second fluid outlet, the valve providing the first predetermined portion of the flow of process fluid to the first fluid outlet and the remaining flow of process fluid to the second fluid outlet in response to a valve drive signal; a first flow meter to measure the first predetermined portion of the flow of process fluid provided by the first fluid outlet and provide a first flow signal; a second flow meter, similar to the first flow meter and tuned to have a similar dynamic response to changes in the flow of process fluid as the first flow meter, to measure the remaining portion of the flow of process fluid provided by the second fluid outlet and provide a second flow signal; an arithmetic circuit to receive the first flow signal and the second flow signal, and provide a feedback signal indicative of a ratio of the first predetermined portion of the flow of process fluid relative to the flow of process fluid received at the inlet; and a feedback controller to receive a setpoint indicative of the first predetermined portion of the flow of process fluid from a process controller that is physically distinct from the feedback controller and the feedback signal and provide the valve drive signal to the valve based upon the setpoint and the feedback signal; wherein the second flow meter is tuned to have a similar dynamic response, in terms of rise time, settling time, and overshoot and undershoot, to changes in the flow of process fluid as the first flow meter.