Bag Filters: Design, Operating Principle, and How to Choose One
A bag filter captures dust with fabric, not an electric field — design, cleaning methods, and how to choose one for your process.
What a bag filter is and how it differs from an ESP
A bag filter cleans gas mechanically — passing it through fabric filter elements (bags) that trap dust particles. An electrostatic precipitator, by contrast, charges particles and collects them electrostatically (see our article on how an ESP works).
Bag filters are usually more effective on fine, abrasive dust and moderate gas volumes, while ESPs are more economical on very large gas flows with moderate pressure-drop requirements.
Bag filter design
A bag filter consists of a housing divided into compartments; fabric bags on cages through which dusty gas passes; a cleaning (regeneration) system that removes collected dust from the bags; a hopper collecting the dust; and a fan or exhauster providing draft.
Bag cleaning methods
Pulse-jet cleaning — a short reverse air pulse shakes dust off the bag; the most common method, allowing cleaning without stopping the filter. Reverse air cleaning — cleaned gas is passed back through the bag in reverse. Mechanical shaking — bags are physically shaken by a drive mechanism, used on lighter-duty filters.
Choosing filter fabric
Bag material is selected for gas temperature and chemical aggressiveness: polyester — for moderate temperatures, the most universal and economical option; aramid fabrics — for elevated temperatures; treated fiberglass — for high-temperature and chemically aggressive streams.
Sizing a bag filter for your process
Sizing requires: gas volume and temperature, humidity, dust chemical composition and particle size, and the required outlet dust concentration. These determine filtration area, bag material, and cleaning method.
Need a bag filter sized for your process?
UK-ZTO-AN designs and manufactures bag filters to your process parameters — with installation and service across Kazakhstan and the CIS.