Hitachi Metals, Ltd.

Arun Nagarajan

Alexei V Smirnov

Ryan Johnson

Patrick Albright

Cy Jordan

Michael John Zolock

Alexander Fernandez

Mass flow control systems and methods for controlling the mass flow rate of a gas through a primary conduit are disclosed. One mass flow control system includes a primary conduit for directing a flow of a gas and an adjustment system configured to divert a portion of the gas from the primary conduit to a secondary conduit and provide an adjustment signal that changes when a composition of the gas changes. A mass flow controller is operatively coupled to the primary conduit to control a primary flow rate of the gas. The mass flow controller includes a valve to control the primary flow rate of the gas and a control loop configured to receive the adjustment signal and control the valve to provide the primary flow rate of the gas at a set point.

Gas insensitive mass flow control systems and methods

Gas insensitive systems and methods for controlling the mass flow rate of a gas through a primary conduit are disclosed. The method includes producing, in a secondary conduit, an assessment flow that has a changing pressure; calculating a first measure of a flow rate of the assessment flow based upon a rate-of-change of the pressure of the assessment flow; and measuring the assessment flow with a mass flow meter that is affected by the composition of the gas to produce a second measure of the assessment flow. An adjustment signal is generated based upon a difference between the first measure and the second measure, and a gas-corrected flow signal is generated by adjusting a measured-flow signal of a mass flow controller with the adjustment signal. The gas-corrected flow signal is used by the mass flow controller to control a flow rate of the gas through the primary conduit.

Mass flow controllers with on-tool diagnostic capabilities and methods for on-tool diagnosis of mass flow controllers are disclosed herein. One method includes opening a control valve to a fixed position and closing an upstream valve to produce a flow rate that decreases from a high flow rate, across a range of flow rates, to a low flow rate. A pressure signal is generated that is indicative of a pressure of the fluid within a volume between the upstream valve and a sensor tube, and a flow sensor signal is provided with the mass flow sensor that is indicative of a mass flow rate of the fluid through the main flow path. Ratio curves are produced that relate, across the range of flow rates, a rate of change of the pressure signal to the flow sensor signal and comparing a test ratio curve to a previously generated baseline ratio curve.

On-tool mass flow controller diagnostic systems and methods

A mass flow controller and method for operating the same is disclosed. The mass flow controller includes a mass flow control system to control the mass flow rate of a fluid, and a data logging component that obtains snapshots of condition-specific-data for each of a plurality of reoccurring condition types, and reduces each snapshot of condition-specific-data to functional parameter values that characterize each snapshot of condition-specific-data, and the data logging component generates statistical values that are stored in a short term data store that characterize multiple functional parameter values that are obtained during each separate occurrence of a specific condition type. A diagnostics component diagnoses failures using current functional parameter values and the statistical values stored in the short-term memory, and a prognostics component predicts failures based upon a collection of data sets that are stored in the long-term memory.

Mass flow controller with onboard diagnostics, prognostics, and data logging

Mass flow controllers with on-tool diagnostic capabilities and methods for on-tool diagnosis of mass flow controllers are disclosed herein. One disclosed method includes effectuating a particular modification to the heating of the one or more heating-sensing elements, and monitoring one or more outputs of the mass flow sensor to obtain present data that characterizes a present operation of the mass flow sensor in response to the particular modification to the heating. Reference data is obtained that characterizes prior operation of the mass flow sensor, and the present operation of the mass flow sensor is compared to the prior operation of the mass flow sensor to assess whether the operation of the mass flow sensor changed over time.

Mass flow controllers with on-tool diagnostic capabilities and methods for on-tool diagnosis of mass flow controllers are disclosed herein. One disclosed method includes providing current to two heating-sensing elements of a mass flow sensor and modifying current through at least one of the heating-sensing elements. Reference data is obtained that characterizes proper operation of the mass flow sensor, and one or more flow sensor signals from the mass flow sensor are analyzed in connection with the reference data to assess whether the mass flow sensor is operating properly.

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San Bruno, CA, United States of America

Arun Nagarajan