TL;DR
Throughput drops when screens are worn, hammers are flipped past their service limit, or the feed rate exceeds the mill's rated capacity. Inspect screens and hammers, and verify the feed rate against the mill nameplate.
What you might see
- feed rate declining to maintain motor load within limits
- motor current at setpoint but throughput below target
- product particle size coarsening despite fine screen installed
- mill sounding more open or hollow during operation
Likely causes
Hammers worn on one side and not yet flipped, reducing effective tip-to-screen clearance
Screen holes partially blocked by fibrous material not passing freely
Feed rate set above the rated capacity for the screen size, causing the mill to choke
Exhaust airflow reduced, back-pressuring the grinding chamber
Required tools
- LOTO kit
- Compressed air for screen cleaning
- Replacement hammers (correct type and weight)
Safety first
- Lock out before opening the hammer mill. Residual rotation and sharp hammers cause severe injuries.
- Grain dust explosion risk. No ignition sources near the mill during operation or inspection.
Procedure
- 1
Lock out the hammer mill and remove the access cover.
Warning: Lock out before entering the hammer mill housing. Hammers are heavy and sharp. Grain dust inside is explosive. - 2
Inspect hammer condition. Hammers worn to the flip indicator should be flipped to expose a fresh face. Hammers worn on both sides should be replaced.[1]
- 3
Inspect screen holes for fibrous material partially blocking the openings. Clear any blocked holes with compressed air.
- 4
Compare the current feed rate setting to the mill nameplate rated capacity for the current screen hole size. Reduce feed rate if above rated.[1]
- 5
Check the exhaust air system. Reduced airflow through the mill increases back-pressure and reduces throughput. Inspect the exhaust fan and duct for blockages.
- 6
After corrections, restore the cover and run the mill at the rated feed rate. Monitor motor current and particle size.
- 7
Log hammer condition and screen wear findings after each inspection for tracking the replacement schedule.
Sources
Bliss Industries Bliss Eliminator Hammer Mill general technical documentation, Bliss Industries
Hammer mill hammer inspection, screen cleaning, and throughput optimization, general feed ingredient grinding practice (general)
More guides for Bliss Industries Bliss Eliminator
How to diagnose rotor bearing failure on a Bliss Eliminator Hammer Mill
Hammer mill rotor bearing failure shows as high vibration and elevated bearing temperature. Measure vibration and temperature at both bearing housings and replace bearings at the first sign of wear.
How to assess and replace worn screens on a Bliss Eliminator Hammer Mill
Worn or broken screens pass oversize particles and reduce throughput. Measure hole diameter and screen thickness, then replace when beyond the wear limit.
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