# Some Important Formulas for Blow Room Section

Introduction:
The blow room section is the first stage in the process of converting raw cotton fibers into yarn. It is a crucial stage that involves opening, cleaning, and blending the cotton fibers to create a homogeneous mass that is suitable for further processing. The quality of yarn largely depends upon this stage. It also affects the CV%. Here trash content is also important. So, we have to know the calculations of blow room as well as the formulas. Some Important formulas for the blow room section are given below.

### Some important formulas for blow room section

…………………………………………………………………..Amount of trash removed
1. Cleaning efficiency of blow room section = …………………………………………. X 100
………………………………………………………………………Total amount of trash

……….Amount of trash in raw cotton – Trash in lap
= ………………………………………………………………………..  X 100
…………………Amount of trash in raw cotton

……………………………………………………….Amount of trash removed
2. Cleaning efficiency of carding (%) = ………………………………………. X 100
…………………………………………………………………Trash in lap

……..Amount of Trash in lap – Amount of trash in Carding
= ……………………………………………………………………………………… X 100
…………………………….Amount of Trash in the lap

…………………………………..The trash in carded sliver (%)
3. Trash in lap (%) = ……………………………………………………X 100
………………………………………100 – Cleaning eff. (%)

………………………Lap length (in gauge)…………Unit of weight
4. Lap hank = ………………………………….. X ……………………………….
………………………..Unit of length…………………..Lap weight (Lbs)

……Lap length (in gauge)………………….1 lb
= ………………………………… X ……………………………………
……………840 gauge…………………Lap weight (Lbs)

5. Blow room production per hour = Surface speed of calender roller (inch/min)

………………60
X ………………………….. X    Eff. %   X   Waste%   X   No. of scatcher
…..36 X 840 X Hank

6. Lap length constant = Lap length X Change pinion

………………………………..Lap length constant
Or, Change pinion = …………………………………..
……………………………………….Lap length

7. Lap length = Surface speed of bottom calendar roller (In gauge)

= Circumference of bottom calendar roller (gauge) X Speed of bottom calendar roller

= (πD/36) X N Gauge (here, D= Dia of bottom calendar roller and N = Speed)

………………………Knock off wheel……………Warm wheel
= (πD/36) X ……………………………….. X ……………………….. (Gauge)
………………………..Change wheel……………..Single warm

8. Lap length constant (%) = Surface speed of bottom calendar roller (In gauge) X Speed from knock off wheel to bottom calendar roller

………………………Knock off wheel………..Warm wheel
= (πD/36) X ……………………………. X …………………………
…………………….Change wheel …………….Single warm

Conclusion:
The delivery product of blow room is lap which is used in carding as feed material. So to make it faultless we have to know the calculation and its formulas.

```Author of this Article:
Md. Abu Sayed
Founder of Textile Apex
Pabna Textile engineering college, Pabna, Bangladesh
Email: [email protected]
Cell : +8801745214773```

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