Baghouse and bag filters
Bag filters handle high dust loads and large air volumes. The pulse cleaning system decides how long the bags last and how much air the fan really moves.
In a baghouse, dust-laden air enters the hopper or the dirty side plenum and passes through fabric bags supported by cages. Dust builds up on the outside of the bags and clean air flows out through the tube sheet.
Each row of bags is cleaned by a blow pipe fed by a diaphragm valve on the header tank. A short pulse of compressed air travels down the pipe and through the venturi into the bag, snapping the fabric and releasing the dust cake into the hopper. Correct pulse energy and pulse timing keep the differential pressure stable across the whole filter.
Typical installation
- A header tank sized to the number and diameter of the valves, in carbon steel, stainless steel or aluminium
- Goyen or Mecair diaphragm valves, full immersion or flat and round mount
- Blow pipes with drilled orifices matched to the bag pitch
- A sequencer controlling the valves in continuous or differential pressure mode
Common challenges
- Uneven cleaning between rows because tank pressure recovers too slowly
- Bags wearing out prematurely from over-cleaning
- Condensate and oil in the compressed air damaging diaphragms
- Emission peaks after each pulse caused by a torn bag or a leaking valve
Industries
- Cement and lime
- Mining and quarrying
- Steel and foundries
- Power generation
- Bulk handling
- Waste incineration
Questions
What size header tank does my baghouse need?
The tank has to refill between pulses without a large pressure drop. As a rule of thumb the tank volume is sized on the number of valves, the valve diameter and the pulse interval. We calculate and build the tank for your filter.
Immersed or flat mount valves?
Full immersion valves sit inside the tank and deliver the most powerful pulse with the shortest air path. Flat and round mount valves are easier to service from outside. Both are available in the Goyen and Mecair ranges.
How do I know a diaphragm valve is leaking?
Typical signs are a continuous hiss, a cold spot on the blow pipe, a compressor running longer than usual and a tank that never reaches full pressure. A repair kit with a new diaphragm and spring usually restores the valve.
Can VDC supply a complete header tank system?
Yes. VDC manufactures complete header tank systems with valves, piping and controls, built to your drawing and certified to PED, and to JIS or ATEX where required.