Blow Room — Opening and Cleaning
topic
The blow room opens cotton bales (compressed at 400–600 kg/m³) to tufts of 0.1–0.5 g, removes trash (leaf, seed coat, mote) reducing total trash content from 2–8% to 0.5–2.0%, and blends multiple bales for lot consistency. Modern blow rooms (Rieter UNIblend/Rieter UniClean, Trützschler Blowroom line) process 600–1500 kg/hr. Cleaning efficiency (CE%) = (trash removed / total input trash) × 100%; target 40–70% without excessive fibre damage (lint loss <5%).
Role
Blow room cleaning efficiency directly determines card loading — insufficient cleaning overloads cards with trash, causing neps and increasing card waste; over-cleaning causes fibre damage that appears as short fibres and drafting resistance in ring spinning. Setting the blow room cleaning intensity correctly for each raw material grade is the upstream quality decision with the highest downstream impact on ring-spun yarn nep count.