Redwood mass flow controllers

The Redwood Mass Flow Controllers (MFCs) were able to control mass flow, but with some limitations. In particular, great care had to be exercised when calibrating the MFCs since the calibration curve sometimes exhibited an inflection point in the flow rate versus set point response. A few MFCs did have linear calibration curves, but many exhibited this nonlinearity to varying extents. This was probably due to the flow measurement and control techniques of these MFCs, which operated by controlling the pressure drop across an orifice. Discussions with Redwood staff indicated that adjusting the internal flow control and measmement parameters for these controllers required a considerable amoimt of work. 

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Valves (SOVs) (this assembly is referred to as the Redwood flow manifold). The composition of the reactor feed gas mixture is defined by setting the flow rates for each of the process gases using these dedicated mass flow controllers (MFCs). 

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