Variations of Fabric Filters
Fabric filters are also known as baghouse and their major role is to clean air or produced gases in the certain processes by the action of trapping the particulate matter in the air or the gas and allowing the clear gas to pass through the fabric. The fabric filters use the separation method referred to as filtration since the air or gases are filtered where the particles remain on the fabric and the gas pass through. This technique of air and gas pollution control is mostly applied in the type of industries that emit fumes and smoke which could contain harmful particulate matter. The industrial requirements of the fabric filters will vary due to a number of factors such the quantity of the fumes and smoke generated by a particular industry hence whereas some industries will require tiny and simple fabric filters, others might require bulky fabric filters. A typical baghouse consists of an inlet which allows the dirty gas into the filter system and an outlet which allows the filtered gas out, an opening at the bottom which drops the collected particles and a tube that attaches to the fabric filters. The manner in which the fabric filters are cleaned or cleared of the particles is the basis of classification of the house bags. This classification of the fabric filters according to the dirt removal mechanism from the surface of the filter fabric yield three types of fabric filters namely, reverse air housebags, shaker housebags, and pulse jet housebags. In reverse air housebags, the bags are suspended, from a hanger at the top which is freely adjustable and the dirty gas enters the bag through the inlet and exits through an outlet from the inside hence the particles or dirt is left on the inside of the housebags. The reverse air housebags are so called due to fact that the cleaning mechanism involves blowing of the cleaning air in a reverse direction such that the housebags collapse momentarily forcing the collected dirt to crack off the surface and drop off. Before this cleaning cycle is begun, the filtration process is first stopped vin the housebags to be cleaned and after the cleaning process the reverse air flow is stopped and the system gets back to normal. For the shaker type of housebags, the dirt is removed from the fabric filter by shaking it off and filtration process is first paused to allow for the shaking to remove the collected dirt hence it’s a mechanical method. Pulse durations of compressed air are utilized in the pulse jet housebags hence the name.