Page 35 - dust collection systems

pressure gauge sends the differential pressure readings to
the controller, which is programmed with a high pressure

and low pressure set point. When the differential pressure

reaches the high pressure set point, the controller activates

the baghouse’s pulse cleaning cycle, which starts cleaning the

bags, lowering the differential pressure. When the

differential pressure reaches the low pressure set point, the

controller shuts down the pulse cleaning cycle. The user sets

the high and low differential pressure set points [generally

1/2” to 1” w.c. (12.7 to 25 mm w.c.) apart], whereby cleaning

will start and stop. By operating the baghouse at a stable and

optimum differential pressure, over or under cleaning of the

filter bags can be avoided. Clean on demand control helps to

lower compressed air consumption, optimizes the dust

collection efficiency (by setting low pressure set point to

maintain a light coating of dust on the bags) and life of bags

also increases due to less flex cycles on the bags.

Clean on demand filter bag cleaning systems may save

energy for facilities with light dust loads. Baghouses that

must clean continuously to maintain an allowable maximum

pressure differential will not benefit from this technology.

Some clean on demand system users have returned to pre-

timed pulses (continuous cleaning) as pressure sensors have

proved unreliable due to clogged tube connections. Some

equipment vendors offer purge air cleaning as an option to
overcome the tube clogging problem.