Page 9 - dust collection systems

approximately 260°C (500°F), which is the maximum long-
term temperature of the most temperature-tolerant fabric.

Fabrics can burn if readily oxidizable dust is being collected.

Fabric filters have relatively high maintenance requirements

(e.g., periodic bag replacement). Fabric life may be shortened

at elevated temperatures and in the presence of acid or

alkaline particulate or gas constituents require special

additives. Respiratory protection for maintenance personnel

may be required when replacing fabric.

Particle Collection Mechanisms in a Fabric Filter

Fabric filters take advantage of the fact that particles are

larger than gas molecules. Therefore, when dirty gas is

filtered through a filter, the particles are captured on the

filter while the clean gas escapes.

Fabric filters operate through a combination of mechanical

particle capture mechanisms/principles. These mechanisms

include; straining, impaction, direct interception and

diffusion. Straining is the process of removing larger particles

(larger than filter pore/opening) or agglomerations thereof.

Large particles are removed by impaction, medium sized

particles are removed by direct interception and very small

size particles are removed by diffusion as explained below.

Particles from an industrial source generally float along the

gas stream. If we put something in their path, they would