Page 14 - dust collection systems

nonwoven fabric also suppresses cake formation. Due to this,
dust cake never becomes fully established and the primary

filtration media is the dust-loaded fabric itself. Hence this

type of filtering is called noncake filtration. A nonwoven

fabric is generally used for filtering very fine particles.

Felted bags should not be used in high humidity situations,

especially if the particles are hygroscopic (these particles

have an affinity to absorb moisture and thus become sticky)

because clogging or blinding could result in such situations.

It may be noted that in both these filtration mechanisms, the

filtration media includes collected dust. In dust cake

filtration, collected dust is the primary filtration media,

implying that understanding the dust properties is the key to

understanding the filtration performance.

Pre-coating / Seeding

For a baghouse to operate efficiently, the fabric filters must

first capture the particles and then release them during the

cleaning cycle. The effectiveness of this process depends on

the development of the dust cake (initial control layer of

dust) that protects the fabric interstices.

Pre-coating is the application of a relatively coarse, dry dust

to a filter element before start-up to provide an initial filter