Multiple-channel flow ratio controller
AssigneeMKS Instruments, Inc.
InventorsMichael L'Bassi, Junhua Ding, David D'Entremont
Life of this patent
Estimating the term…
Abstract
A system for dividing a single mass flow into a plurality N of secondary flows includes an inlet configured to receive the single mass flow, a master FRC (flow ratio controller), and one or more slave FRCs. Each FRC is connected to the inlet and including at least one flow channel. The master FRC and the slave FRCs include in combination a total of N flow channels. Each flow channel i (i=1, . . . , N) is connected to carry a corresponding one of the N secondary flows. In response to preselected ratio setpoints received from a host controller, the master FRC and the slave FRCs maintain ratios Qi/QT (i=1, . . . , N) between individual flow rates Qi (i=1, . . . , N) and a total flow rate QT at the preselected ratio set points.
Claims13
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 Qi/QT (i=1, . . . , N) between individual flow rates Qi (i=1, . . . , N) of the respective secondary flows of respective secondary flow channels and total flow rate QT at preselected ratio set points, wherein Qi represents individual flow rate in flow channel i, and QT represents a sum QT=Q1+ . . . +Qi+ . . . QN of all N individual real time flow rates of the secondary flow channels as measured by the respective flow sensors;
- 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 QT to each of the slave FRCs, and to deliver to each of the one or more slave FRCs the respective preselected ratio set point along with one or more command signals;
- and
- 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 QT, by adjusting a flow rate of each of the secondary flow channels to satisfy a respective one of the preselected ratio set points received from the master FRC.
A system for dividing a single mass flow, comprising:
- an inlet configured to receive a single mass flow from an outlet manifold, the single mass flow being provided by two or more gas suppliers connected to the outlet manifold, each gas supplier comprising a metered amount of gas;
- a plurality of FRCs (flow ratio controllers) connected to the inlet, wherein the plurality of FRCs comprises a master FRC and one or more slave FRCs, each FRC comprising at least two flow channels, each having a flow sensor for measuring a real time flow rate through the flow channel and a valve for controlling a portion of the single mass flow through the flow channel;
- a controller operably connected to the master FRC, the controller configured to provide preselected flow ratios for plurality of the FRCs;
- a digital communication bus connected to the controller and the master FRC and the one or more slave FRCs, and enabling communications between the master FRC and the one or more slave FRCs, or between the master FRC and the controller;
- wherein each FRC is configured to maintain, based on its respective preselected flow ratio, a respective flow ratio between a real time flow rate measured at the FRC by a corresponding flow sensor of each of the flow channels of the FRC and a total flow rate as determined by the controller by summing all of the real time flow rates measured by the flow sensors of the plurality of FRCs,
- wherein the master FRC is configured to receive the preselected flow ratios from the controller and deliver one or more respective flow ratio set points to the one or more slave FRCs to maintain the respective flow ratio of each at the respective one of the preselected flow ratios.
Dependencies are inferred from the claim text.