Dust collector and venting filters — high differential pressure, dust escaping
Symptom
Differential pressure is high and rising (or very low), dust comes out of the outlet or escapes at the mixer and weigh hopper, a pulse valve is silent, or cement weighing is unstable while filling.
Likely causes
- Filter elements blinded, often by wet compressed air.
- Pulse cleaning failed - diaphragm, solenoid or air supply.
- Dust discharge (screw, rotary valve, flap) blocked.
- Element torn, missing or badly seated (low ΔP, dust out).
- Fan weak, or mixer and hopper seals leaking.
Most likely and cheapest to check first.
Checks
- Read the differential pressure daily and record it at least weekly.
- Look for visible dust at the outlet daily.
- Listen to the pulse valves firing in sequence weekly.
- Check the compressed air is clean and dry at the maker's pressure.
Fix
- Repair pulse valves and the air supply; fix the dryer and drains (Book 7).
- Clear the dust discharge.
- Replace elements as a set; check seals and seating.
- Service the fan; replace mixer and hopper seals.
Parts you may need
A blinded filter upsets the scale
When cement drops into the weigh hopper or the mixer it pushes dusty air out. If the vent filter cannot breathe, pressure builds in the hopper and the load cells read it as weight.
CAUTIONLock out before opening any filter. Pulse valves fire without warning and the fan can start. Cement dust is alkaline - goggles and a mask.
⚠ Every check inside a machine starts with full lockout. Safety disclaimer