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STACK FLOW RATE SENSOR

  Stack Flow II

Using paired electrodynamic sensors, PCME has developed a device for monitoring stack flow rate.  The Stack Flow II measures velocity which, combined with the stack cross-sectional area, results in a flow measurement.

 

The velocity measurement is based on time-of-flight principle.  The velocity (V) of the gas is determined from the time (T) required for particles to travel a known distance (S):

 

V = S / T

 

 

 

The electrodynamic signal from two probes is used to identify shifts in particulate concentration.  Cross-correlation numerical techniques are used to match patterns from the two probes and to determine the lag time between the two response curves.

 

 

 

The time-of-flight measurement has several advantages over other measurement techniques:

 

 

The plot below shows the response of the instrument when compared to the manual velocity measurement:

 

The Stack Flow II is not limited to the same applications as the standard electrodynamic sensor.  Because a concentration measurement is not being made, the Stack Flow II can be used after electrostatic precipitators or wet scrubbers.