# Textile Calculation

## How to Find Out the Weight of Blow Room Lap

How to Find Out the Weight of a given Length of Lap
Amit Kumar Das
Founder of "টেক্সটাইল ম্যানিয়া" Blog
Pabna Textile Engineering College, Pabna, Bangladesh
Cell: 01770 456240
Email: amitptec6th@gmail.com

Lap is a sheet of fibers or fabric wrapped round a core with specific uses in different sections of yarn manufacturing industry such as sheets of fiber wound on rollers.

 Blowroom lap
Sheets of cotton bales are feeded between lap roller and shell roller then pressure is to apply at both the end of the lap roller. This pressure initiates the formation of the lap on the lap roller in blowroom. Lab is the ultimate output material of blowroom.

Mathematical Problems and Solutions:

Problem: 01
What is the weight of 12 yards of lap of hank-lap 0.00127 ?

Solution:

Weight in lbs. = Length in yards ÷ (840 × Hank )

Weight of 12 yards lap = 12 ÷ (840 × 0.00127)
= 11.9 lbs. (ANS)

Problem: 02
1000 yards length of card sliver of 0.15 hank is packed into a box. What is the net weight of sliver?

Solution:

Weight in lbs. = 1000 ÷ ( 840 × 0.15 )
= 7.937 (ANS.)

Problem: 03
A blowroom lap weighting net 45lbs. has 14 ounces per yard. Find the length of lap and how long does it last on a card whose 2.25’’ feed roller rpm is 1.25?

Solution:

Length of lap = (45 × 16) ÷ 14 = 51.43 yards

Length of lap fed to card per minute,
= (22/7) × (9/4) × (1.25/36) yards

Time of one lap running on the card,
= 51.43 ÷ { (22/7) × (9/4) × (1.25/36) }
= 3.5 hours (approx). (ANS.)

Problem: 04
Find the actual draft and mechanical draft of a finisher scutcher which is using breaker laps weighting 15 ounces per yard and produces 14 ounces per yard. The droppings beneath the beater is 1.2% ? (Note: Four breaker laps are doubled on the finisher scutcher machine)

Solution:

Actual draft = (15 × 4) ÷ 14 = 4.29

Mechanical draft = { ( 15 × 4 × 100 ) ÷ (14 ×101.2) }
= 4.23 (ANS.)