Bag-House Dust Collectors


There are three types of bag-house cleaners: reverse jet, reverse air and mechanical shaker .

Reverse Jet

This type uses individual bags. These bags are supported by a metal cage, which is attached to a cell plate at the top of the bag-house. Dirty gas flows from through the bottom of the bag-house then inside the bags.

Compressed air cleans the bags, injected through a shared manifold over a row of bags. The compressed air is pushed through by a venturi nozzle mounted at the top of the bag. The compressed-air burst is only .1 of a second, causing it to act as a constantly moving bubble of air, which travels the entire length of the bag and cause the surface of each to inflate. The inflation will break up a built-up dust layer, called a "dust cake", it then falls into a storage hopper below.


Reverse-jet dust collectors can be operated continuously and cleaned without having to interrupt the filtration. This is because the compressed air shot is very small compared to the amount of dust in the bag-house. These collectors are usually not compartmentalized because of the continuous-operation feature.


Because of the short cleaning cycle,  recirculation and redepositing of dust is reduced. Reverse-jet collectors collectors provide more complete cleaning and reconditioning of bags than mechanical shaker or reverse-air collectors. Space consumption is as well lower because of higher air-to-cloth ratios, caused by the continuous-cleaning feature.

Reverse Air

In reverse-air bag-houses, the bags are attached to a cell plate at the bottom of the bag-house (as opposed to the top), they are suspended from an adjustable hanger frame at the top. A flow of dirty air will normally enter the bag-house and pass through the bag from the inside, where it then collects the dust.


These types of collectors are compartmentalized, which allows it continuously operate. Filtration has to be halted so the bag-house can be cleaned (as opposed to reverse jet bag-houses). This is done by injecting clean air into the collector in a reverse direction, pressurizing the compartment. The bags then collapse partially because of the pressure, causing the "dust cake" (layer of built-up dust) to crack and fall into the hopper below. Once cleaning is finished, reverse airflow is discontinued, and the compartment is returned to the main stream.


The dirty air flow helps maintain the bag's shape within the collector. During cleaning, to prevent the bag from collapsing and to prevent fabric chafing, rigid rings are sewn into the bags at intervals. Space requirements for a reverse air bag-house are less than those of a mechanical shaker bag-house, maintenance needs are, however, greater.

Mechanical Shaker

In mechanical shaker bag-houses, tubular filter bags are attached to a cell plate at the bottom of the bag-house, suspended from beams at the top. These top beams are shook to clean the bag-house, the dust cake breaks because of vibration produced by a motor-driven shaft and cam. Dirty air enters from the bottom of the collector, passing through the filter. The dust is then collected on the inside surface of the bags.


This type of bag-house ranges in size, from small, handshaker devices to large, compartmentalized units. They can operate continuously without interruption.  When processes operate through batches and a batch is completed, the bag-house can be cleaned. Continuous processes use compartmentalized bag-houses. Filtration can be directed to the other compartments when one is being cleaned.


In mechanical shaker bag-houses, there must be no positive pressure inside the bags during cleaning. Pressures as low as 0.02 in. wg can interfere with the process. The air-to-cloth ratio for shaker bag-houses is relatively low, causing it to take up a large amount of space.They are, however, popular in the minerals processing industry because of their simplicity.