Hi everybody

What is the meaning of Pulsation Frequency which is monitored by the Flame scanners in furnace applications ? How is it different from the flame frequency?

Regards & TIA

Karthik

 

In response to Karthik's query, following is an overview, some of which was excerpted from the consultant listed below:

Pulsation Frequency is a manifestation of burner instability in virtually any combustion process. It is a thermoacoustic phenomenon resulting from inadequate "mixing" of fuel and air. It affects:

A) Flame Detectors
Rhythmic flame position and intensity variations occur that are synchronized with the pulsations. The result is variation of the flame scanner output signal, regardless of type, i.e., IR or UV. The rate of observed variation is referred to as "flame frequency." An analogous observation would be circular motion of the "fireball" in
tangential-firing furnaces. The fireball rotation can be detected by signal strength variation of sequentially positioned flame scanners.

B) Mechanical Integrity
The resultant "breathing" of the furnace or fire box structure produces noise. If intense enough, the ensuing vibration could negatively impact
on the mechanical structure causing severe shaking... even failure.

Pulsation elimination can sometimes be accomplished through alteration of existing hardware. But, more often, some sort of mechanical
reconfiguration is required.

If you need additional clarification or detail about Pulsation Frequency, contact Dan Banks, PE:

Banks Engineering Inc.
Tulsa, OK
(T) 918-740-5657
(F) 918-747-3366
(w) WWW.banksengineering.com

If you need additional information about improving flame scanner reliability to eliminate unwarranted (false) trips, then contact me.

Regards,
Phil Corso, PE
Trip-A-Larm Corp