To determine count of yarn using wrap reel.
AIM:- To determine count of yarn using wrap reel.
APPARATUS:– Wrap reel, weight balance and fractional weight box.
PRINCIPLE:-
In indirect count system the count is the number of units of length per unit weight of yarn. In this system higher the count finer is the yarn. On other hand in direct system the count of yarn is the number of units of weight per unit length of yarn. In this system higher the count, coarser the yarn.
THEORY: –
The count of yarn is a numerical expression which defines the fineness. This is also called yarn number or linear density. The fineness of yarn cannot be expressed easily in terms of diameter as in case of wires or rod because the yarn is not uniform and also relatively soft and compressible. Also the cross section of spun yarn is not fully circular. It contains various variations in thickness because of the presence of thick and thin places. Therefore following methods are used to determine the fineness or coarseness of yarn.
PROCEDURE:-
There are two basic requirements in determination of count. They are
1. Accurate value of length of yarn
2. Accurate value of weight of yarm
Length measurement:-
For the yarn which is in package form such that in ring bobbin, it is usual to wind the number of skeins by means of wrap reel. Make of wrap reel is ‘HIROSHIMA manufactured by Apex Enterprises It consists of creel, yarn package holder, a yarn guide and a small sideways traverse which spreads the loops of yarn evenly. Wrap reel is motor driven and has periphery of 54 in so turat revolution of creel produces a skein of 120 yards termed as lea.
For determination of yarm count, spun yarn from ring frame bobbins or often formed of primary package with large package such as cone, cheese have to take and wrap skeins from each other.
After preparation of lea the material is allowed to condition at standard testing atmosphere for 24 hours for each lea.
Weight measurement:-
Weight is measured by means of a balance. Here simple mechanical balance is used. The registered name is ‘ROY BALANCE’. Before going for any reading the balance is ready to take weight of each lea.
| SR NO | LENGTH IN YARD | WEIGHT IN GRAMS | COUNT(X) | (X-x) | (X-x)² |
| 1 | 120 | 1.768 | 36.65 | 0 | 0 |
| 2 | 120 | 1.793 | 36.14 | -0.57 | 0.3294 |
| 3 | 120 | 1.802 | 35.96 | -0.69 | 0.4761 |
| 4 | 120 | 1.824 | 35.92 | -0.73 | 0.5329 |
| 5 | 120 | 1.775 | 36.50 | -0.15 | 0.0225 |
| 6 | 120 | 1.760 | 36.81 | 0.16 | 0.0256 |
| x=36.65 |
LENGTH IN YARD Χ 453.6
1) NE = ———————————————–
840 x WEIGHT IN GRAM
120 X 453.6
=——————— = 36.65
840 X 1.768
2) SD= √∈(X-x)² √0.3026
—————– = ——————– = 0.18
n-1 10.1
3) cv % = SD 0.18
——— X 100 = ———— x100 =0.4911 %
Mean 36.65
4) variance = (S.D)² = (0.18)² =0.0324
