Patent ID: 8849589

Claim:
A process fluid flow device for measuring energy flow rate of a fluid comprising one of steam, water, or natural gas, the process fluid flow device comprising: a power supply module; process communication circuitry coupled to the power supply module; a processor coupled to the process communication circuitry and the power supply module; measurement circuitry operably coupleable to a temperature sensor, a static pressure sensor and a differential pressure sensor to measure an indication of differential pressure across a differential pressure producer and temperature of the fluid; memory containing data related to energy content of the fluid per unit mass of the fluid; and wherein the processor is coupled to the memory and configured to compute mass flow of the fluid as a function of measured temperature, static pressure and differential pressure of the fluid, determine an energy content per unit mass value of fluid using a polynomial equation and the data contained in the memory, and provide an energy flow rate output of energy per unit time based upon a multiplication of the mass flow times the energy per unit mass value; wherein the energy flow rate for steam, water and natural gas is calculated using the polynomial equation.