C.3 Dynamic Compensation Flow Equation, Continued

SMV Operation in a Steam Application

When operating the SMV in a steam application there are number of considerations you should be aware of.

Be sure the process is at or above saturation when operating the SMV, since the SMV does not calculate flow when the process is below saturation.

Operating limit for absolute pressure input is 750 psia(for Model SMV125), but SMV will continue to make calculations for inputs up to 1500 psia.

SMV Model SMG170 will operate and calculate to 3000 psig. At pressures greater than 2000 psia you must operate at less than 100 °F of saturation temperature.

Operating range for temperature input is saturation to 1500 °F (815.5 °C), assuming that the temperature sensor used (RTD or thermocouple) can cover this range, with the exception noted above.

Example: Superheated Steam

An engineer has specified a SMV 3000 Smart Multivariable Transmitter to dynamically compensate and calculate the mass flowrate of superheated steam through a standard 304 SS orifice meter with flange taps. The engineer has sized the orifice meter to produce a differential pressure of

241.3inches H2O at 22,345 lb/hr. The flowing pressure is 64.73 psia and the flowing temperature is 350 degrees F.

The steps in Table C-5 shows how to configure the SMV to calculate the PV4 flow variable for this application.

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Honeywell SMV 3000 user manual SMV Operation in a Steam Application, Example Superheated Steam