Page 34 - dust collection systems

vertically as a nearly direct replacement for standard bags
and cages in existing baghouses

Types of Cleaning Controls

Normal pressure drop for a bag filter will fall in the range of 2

1/2 to 6 inches of w.c. (water column) after the elements

(filter bags) are broken in. The differential pressure reading

will increase as the elements get dirty and the filter must

eventually be cleaned or airflow will fall to unacceptable

levels.

Bag filters are available with “continuous” or "clean on

demand" cleaning control. Continuous cleaning type bag

filters are cleaned with pre-timed pulses of compressed air

regardless of cleaning need. However, clean on demand

filters are cleaned based on the pressure drop monitored

across the filter bags.

A typical automatic clean on demand system for a pulse jet

baghouse consists of a differential pressure gauge

(Switch/Gage, a 2-in-1 instrument combining differential

pressure gage with low- and high-pressure switches) and a

programmable controller. The differential pressure gauge

measures the difference in pressure between the dirty air

side and clean air side of the bags in the baghouse. The