Get to Know About Baghouse Filters

The air pollution control devices which are designed to capture or separate dust and other particulate matter (PM) are called baghouse filters. Also referred to as fabric dust collectors or fabric filters, these filters are widely used in a variety of places such as in small household workplaces and large industrial facilities including coal-fired power plants and cement plants.

Baghouses are incredibly handy when compared to other air pollution control equipment. These can be engineered for almost all types of dust producing appliances just by resizing and changing the bag type. Proper maintenance of these filters enhances its efficiency to effortlessly handle rough applications. Their use is also restricted to specific operating temperatures, weather and chemical conditions.

Baghouse Filters

Baghouse Collector Operation

Baghouse filters consist of filtering media suspended inside a casing. Fans on the outside of the casing blow the polluted air through the filters, thus capturing the suspended particulate and solids on the bags and pushing clean air through the outlet. While filtering, a baghouse pocket entitles the creation of a layer of particulate on its surface called a dust cake. The dust cake continues to form until the thickness reaches a point where the flow is stopped. At this point, the bags are cleaned.

The dust cake on the bag filters continually thickens as air is filtered through the baghouse filters. The encrust does most of the filtering of the particulate matter in the air stream. A thicker dust cake enhances both the collection efficiency and pressure drop as the pathways through the bag become finer. Frequent cleaning leads to lower collection efficiency and reduction of bag life. However, insufficient cleaning can cause excessive energy requirements for blower fans that are, high-pressure drops.

Performance Specifications

While selecting baghouse filters, the most vital performance specifications to be considered are listed below:

- Airflow or volumetric flow rate is the acceptable flow rate of the gas stream through the baghouse which is measured in cubic feet per minute. An increase in gas flow rates results in the increase in operating pressure drop and air-to-cloth ratio. With the increase in airflow rate, the baghouse filters need to work more persistently, leading to more frequent cleanings and high particle velocity, the two factors that lessen bag life.

- The smallest diameter of particulate matter that a baghouse is capable to filter is called minimum particle rate. It is measured in micrometres. This rating effectively defines the filtering capacity of the baghouse, which should satisfactorily meet the requirements of the system.

Applications

The baghouses are particularly designed to cater to the needs of several industries or applications. Some applications of baghouse filters include:

Baghouse Filters

Abrasives – The baghouse fabrics are designed to endure and collect coarse particles.

Acid gases – The baghouse fabrics are encrusted with powdered lime or similar substances to absorb acid gas.

Coolant and oil mists – The unit should be able to filter coolant smoke and mist from metal finishing.

Explosive media – The unit is capable of filtering explosive dust, mists, and fumes.

Fine powders – The unit is able to filter fine powders such as carbon black, talc, pigments, oxides and plastic compounding dust.

Mercury – The fabric of baghouse filter is coated with activated carbon in a powdered form that aids in absorbing mercury or other deceptive air pollutants.

Toxic media – The unit is capable of filtering toxic materials including dust, mist, fume and smoke from the air.

Welding fumes – The unit is designed exclusively for the collection of welding fumes or dust. These may include flux recovery systems.

Thus, to keep the environment safe and pollution free usage of baghouse filters is of utmost importance. Installation of this device should be made mandatory in any of the plant or factory. This is an ideal way to stay away from various sorts of fatal diseases.