Waste Calculation in Blow Room

Cotton contains a huge amount of dust, foreign matter, seed, and other particles. In this article, we will know the waste calculation in blow room. Before calculating blow room waste we have to know which are blow room waste. Dropping-II, Dust, filter waste are the blow room waste. Normally, fibers represent about 40 – 60% of blow room waste. In order to clean, it is necessary to eliminate about as many fibers as foreign material. During the spinning of cotton yarn, some wastes produce at different stages. We can classify it into three categories. They are as follows:

  1. Directly reusable waste;
  2. Dirty waste, and
  3. Dust and fly.
Waste Calculation in Blow Room
Fig: Blow room waste (dropping)

Waste Calculation in Blow Room:

Waste removed from the blow room is very important regarding the cleaning efficiency of the blow room.

  1. Waste = lint + trash
  2. Input = output x (100/100 – Waste%)
  3. Output = input – waste
  4. Waste% = waste x 100/input
  5. Cleaning efficiency = waste extracted x 100/total waste

Some examples of waste calculation in blow room are given below for clear concept:

Question 1: 
80 bales of cotton each of 167 kg, are being fed daily in a 2-scutcher blow room line. Actual production per 2-scutcher per day is 12000 kg. Calculate the total quantity of waste throughout the whole blow room line & waste %age.

Solution:

Input = 80 x 167 = 13360 kg
Output = 12000 kg
Waste = 13360 – 12000 = 1360 kg
Waste% = 1360 x 100/13360 = 10.18% (ANS)

Question 2: 
Production per hour from scutcher of 3-scutcher blow room line is 310 lbs. waste %age of blow room is 6.5%. Calculate the no. of bales to be fed in a given blow room per month provided that one bale is os 168 kg.

Solution:

Blow room output per day = 310 x 3 x 24/2.2046 = 10124.7 kg

…………………Input – Output
Waste% = ………………………… x 100%
Input

……………Input – 10124.7
=> 6.5 = ………………………… x 100%
…………………Input

=> (100 – 6.5) input = 1012474.5 kg

Input = 1012474.5/93.5 = 10828.6 kg/day

Hence no. of bales fed per month
= 10828.6 x 30/168
= 1934 bales (ANS)

Question 3: 
The production per scutcher per hour in a 2-scutcher blow room line is 325 lbs. waste from whole blowroom line is 700 kg/day. Calculate the no of bales required per day for given blow room line. (1 bale = 167 kg).

Solution:

Waste = 700 kg
Output = 325 x 2 x 24/2.2046 = 7076.4 kg/day
Input = 7076.4 + 700 = 7776.4 kg/day
No of bales/day fed = 7776.4/167 = 47 bales (ANS)

Question 4: 
63 bales of cotton are being fed daily in a blow room line consisting of 2-scutchers. The blow room is to be kept stopped for one hour after each shift for maintenance. If waste %age is 6.5%, what will be the production per scutcher in kg/hour, while 1 bale = 166 kg.

Solution:

Input = 63 x 166 = 10458 kg/day
Waste = 10458 x 6.5/100 = 679.77 kg

Output = 10458 – 679.77
= 9778.23 kg/day

Prod. Per scutcher per day = 9778.23/2 x 21
= 232.82 kg/hour (ANS)

Question 5: 
80 bales of cotton are being fed in a blow room line daily. If the pure weight of cotton per bale is 168 kg and waste% of blow room line is 6%.

  • What will be the wt. of cotton lap received per day from the scutcher.
  • Calculate the no. of laps prepared per day if the wt. of one lap is 22kg.
  • If the lapping rod is 2kg then calculate no. of pure lint laps.

Solution:

Input = 80 x 168 = 13440kg
Waste = 6%

Waste = 13440 x 6/100
= 806.4 kg

Output = 13440 – 806.4
= 12633.6 kg/day

This is cotton lap received per day

No of laps/day = 12633.6/22
= 574.2 laps

Pure lint laps/day = 12633.6/20
= 631.68 laps (ANS)

Question 6:
A lap of 50 lbs with a length of 55 yds is being prepared on a scutcher in 4.5 min. if the waste %age of blow room line 7%, what should be required no. of bales to be fed daily if bale wt = 170 kg

Solution:

50 lbs are prepared in = 4.5 min

In one hour = 50 x 60/4.5
= 666.67 lbs

Production per day = 666.67 x 24
= 16000 lbs/day

Hence,
Input = 16000 (100/93) = 17204.3 lbs/day

No of bales = 17204.3/2.2046 x 170
= 46 bales (ANS)

Question 7: 
The total material fed into a step cleaner was 800 lbs/hr. The cleaning efficiency of the machine was found to be 35%. The total material delivered per hour was found to be 2% less than the fed material. Calculate the total quantity of waste as well as trash per hour. If there is 80% trash of total waste.

Solution:

Input = 800 lbs/hr
Output = 800 (1 – 0.002) = 784 lbs/hr

Waste = 800 – 784 = 16 lbs
Waste% = 16 x 100/800 = 2%
Trash% = 80% of waste

Trash = 16 x 80/100 = 12.8 lbs (ANS)

Author of this Article:
Mustaque Ahammed
Quality Assurance Officer,
Lamisa Spinning Ltd. Tongi, Gazipur 
Cell: +8801723300703
Email: mamuntex09@gmail.com

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