Providing accurate and reliable steam flow measurement to the steam host is a very important aspect in generating revenue for the co-generation facility. The existing annubar flow measurement system could not measure the low end of the steam flow requirements without major changes to the piping and purchasing a new annubar. (McCrometer, Inc.)

Annubars have been used for years on flare applications. An annubar is a differential pressure device with the signal increasing proportional to the square of the flow. Annubars are good for high flow rate applications, but are not good for low flow applications due to the small pressure difference these flows represent. For mass flow applications, annubars require pressure and temperature compensation. (ABLE Instruments & Controls Limited)

Both the pitot tube and annubar contribute very small pressure drops, but they are not physically strong and should be used only with clean fluids. (pc-education.mcmaster.ca)