Bag Filter & Sieving Systems

A bag filter is a system used in industrial facilities to capture dust generated at dusty work points at the source. Dust is drawn from the undesired environment by the fan in the system; micron-level dust is conveyed through ducting to the filter. Inside the filter, the airflow is slowed down — by which dust settles by gravity. Fine dust that does not settle adheres to the surface of the filter bags and is separated from the clean air.

Filter bags are automatically cleaned at intervals (via jet-pulse, mechanical shaking or reverse-flow mechanisms); accumulated dust falls into the collection bunker and can, if required, be returned to the process via a rotary feeder or screw conveyor.

Bag filters are used in all industrial facilities working with bulk materials:

• Cement and lime plants: kiln outlet, crusher, mill, clinker silo ventilation, packing station — the sector's highest filter-use area.

• Mining and aggregate: dust control at crushers, screens and transfer points.

• Iron-steel: slag, coal and ore transfer points.

• Power plants: coal yards, ash silos, boiler feed.

• Grain and food: silo ventilation, milling units, packing lines.

In each application, air volume, dust concentration, temperature and dust type are evaluated to select the filter area and bag type.

The filter bag is the heart of the filter. Correct material selection directly determines filter performance and life:

Sieving systems are equipment used in the mining sector for classifying material by particle size. By selecting openings according to the target sieved sizes, the number of sieving classes is determined; products are classified and stacked separately as undersize and oversize.

Vibratory sieves (vibratory screens), thanks to their multi-deck design, can perform multiple size classifications in a single machine. They are widely used in mining and aggregate facilities to distribute the post-crushing product into size-based stockpiles.

Both bag filters and sieving systems are designed in modular form. Filter surface area (m²) scales with capacity requirements; in larger facilities, multiple modules are combined to provide the total suction capacity.

The same logic applies to sieves: manufacturing ranges from low-capacity single-deck units up to multi-deck classification screens with large surface areas. For every project, TMD GRUP sizes the unit based on the customer's air volume, material flow and planned future capacity growth.

A critical feature of modern bag filters is automatic cleaning. Three main mechanisms are used:

• Jet-pulse cleaning: high-pressure air pulses are sent through the bags from inside to outside at intervals; accumulated dust is dislodged and falls into the bunkers. This is the most common method for continuous production.

• Mechanical shaking: bags are mechanically shaken to release dust. An older design.

• Reverse flow: cleaned air is sent through the bag in reverse direction; accumulated dust falls.

TMD GRUP generally prefers the jet-pulse system; it cleans the filter without stopping production and provides maximum uptime.

Bag filter or sieving system projects at TMD GRUP proceed in the following order: suction-point analysis (dust type, temperature, volume, concentration) → filter surface area / sieve configuration calculation → bag material and cleaning system selection → engineering design and 3D integration (ducting, fan, control panel) → manufacturing (Başkent OSB) → in-house performance testing → site installation, ducting connections, fan calibration → commissioning and emission measurement.