Patent ID: 8997791
Filing Date: 2015-04-07
Classification: G05D,Y10T

Abstract:
1. A method of controlling flow in a plurality N of secondary flows that drive from a single mass flow, that is combined in an outlet manifold from two or more mass flows from a plurality of gas suppliers, each of the two or more mass flows individually being metered through a respective mass flow controller, the method comprising: connecting a master FRC and one or more slave FRCs to an inlet configured to receive the single mass flow, the master FRC and the slave FRCs each including at least two secondary flow channels and including in combination a total of N flow channels, each flow channel i (i=1, . . . , N) connected to carry a corresponding one of the N secondary flows, and wherein the master FRC and the slave FRCs are multiple-channel FRCs, each multiple-channel FRC respectively including at least two of the N flow channels, and wherein each secondary flow channel includes a respective flow sensor for measuring a real time flow rate through the flow channel and a valve for controlling gas flow through the flow channel; with a digital communication bus, providing preselected flow ratios from a host controller to the master FRC for the master FRC and the one or more slave FRCs, wherein the digital communication bus is configured to provide communications between the master FRC and the one or more slave FRCs, or between the master FRC and the host controller; and the master FRC and the one or more slave FRCs maintaining, in all the flow channels, ratios Q wherein the master FRC is configured to receive preselected ratio set points from the host controller and to receive a real time flow rate measurement from each secondary flow channel, and to provide Q wherein each slave FRC is responsive to an actual flow ratio, between a real time flow measurement for each of the associated flow channels and Q