# Textile Calculation

## Some Important Formulas for Blow Room Section

Some Important Formulas for Blow Room Section

Md. Abu Sayed
Founder of Textile Apex
Pabna Textile engineering college, Pabna, Bangladesh
Cell : +8801745214773

Introduction
Blow room is the first stage of spinning where opening, cleaning, mixing and blending are done. 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. The important formulas 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 lap

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 calendar 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 = 1                     Single warm

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