Bag Filters – Clear Solution

Bag filters are constructed from felted fabric or woven. Generally used for dust removal in industrial applications. Bag filters are also available in many materials ranging from fiber to metal.

Bag filters are in general not designed for replacement when they are clogged, but some other kind for gaseous applications like dust removal can be cleaned.

Depending on the application, the separation of particles happens on the internal surface of the filter, the flow came from inside to the outside of the filter, or the other way around. Bag filters can be designed from small to large. They can up to 30 or more feed long across.

filter bags

Some bag filters are compact, that mean self-cleaning. They have duty dust collection system continuously that economically meets the need of most industrial application. The advanced system utilizes pulse jet cleaning, that effectively dislodges the captured dust from the bags and cleans the filter while the systems are running.

Compact bag filters can be used in processing chemicals, petroleum derivatives, coolants, cutting oils, cleaning fluids, waxes, paints, inks, resins, varnishes, lacquers, pharmaceuticals, plasticizers, plastisols, food stuffs, vegetable oils and edible oils. They are particularly useful for filtering large volumes of high viscosity liquids.

Bag filters are preferable for systems with contaminations greater than 100 ppm that is to say with contamination levels greater than 0.01% in weight.

You may want to check out articles on Cellophane Bags, Polypropylene Bags and Sand Bags.

Bag Filter Applications

Recovery of particulate matter from exhaust gas is important for any industry to avoid pollution problems and recovery of finished product. If material recovery in powder form is desirable and particulate size is very fine, a bag filter is the best choice for recovering particulate matter. In many filtering applications, bag filter is used as liquid filtration such as bulk chemical, food industry (vinegar), waxes, coolants, paint, varnishes. For gaseous filtration in industry, bag filter is used for dust removal. General components of bag filter

• bag filter housing
• filter bags
• bag cages
• filter bag assembly
• pulse-jet air cleaning assembly
• air bleeding assembly

Bag Filter Work Priciple

bag filter housing

• the dust-laden air enters the bag filter housing trough the bustle.
• the air is uniformly distributed avoiding channeling.
• Initially a coat of material forms on the bags. Subsequently, the coat acts as the filtering medium.
• the dust is accumulated on filter elements while the air passes thorough the filter bags from outside to inside.
• the accumulated powder is dislodged from the bags by reverse pulse-jet air intermittently.
• the dislodged powder falls on bottom cone and is discharged through powder discharge valves.
• the dust free air is sucked by induced draft fan and is exhausted to atmosphere.

Bag filter can be made from nylon, polypropylene or polyester. Polypropylene bag filter is often used as filtering material. It is compatible in most situations for filtering acids, alkalis, aromatics, alcohols and ethers. Most bag filters are designed for applications with a desired filtration rate from 1 to 1000 micron.

You may want to check out the other article on Bulk Packaging.