ABSTRACT
Flow rate may be inferred from a measurement of gas velocity in a pipe or duct. The velocity measurement can be made with the jet deflection flow detector. Air or another gas that is compatible with the process is expelled from the nozzle, forming a jet with the pressure profile shown. Features that are superior to those of conventional pitot sensors include the provisions of continuous backpurge and the auxiliary cleaning jets, which keep the receiver ports clean; the fact that the element is heated to a temperature above the dew point, and therefore condensation is avoided: and the linear output signal which is much stronger then that of a conventional pitot. Probe-type instruments, such as the jet deflection element or the pilot tube, can be installed so that they can be removed for inspection without shutting the process down.
