YARN SYSTEM AND INSTRUMENT USED

1. Prepared by

3.  The count of yarn is a numerical expression
which defines its fineness.
 It is also called as yarn number or linear density.
 According to the definition given by the Textile
Institute, Count is a number indicating the mass
per unit length or the length per unit mass of
yarn.

4.  Several systems and units are used for expressing the yarn
number, depending on the material used for preparing the
yarn and the locality where the yarn has been
manufactured.
 All these systems are grouped into the following
categories:
1. Indirect system
2. Direct system
3. Universal system

5.  In this system the count is the number of
units of length per unit of weight of yarn.
 In this case, higher the count, finer is the
yarn.
 This system is generally used for cotton,
woolen, worsted, linen, etc.

6.  The weight of the fabric can be calculated easily,
when the count of warp and weft yarns are
expressed in this system.
 The amount of twist in the yarn and cloth setting
(threads per inch) are directly proportional to the
square root of the yarn count and they can easily
calculated.

7.  The count does not express the size of the yarn
directly. A coarser or bulky yarn will have a small
count number than a finer or less bulky yarn.
 When the component threads are of different
counts, it is difficult to calculate the resultant
count of the folded yarn in this system.

8.  In this system, the count of the yarn is the
number of units of weight per unit length of
yarn.
 This system is used for silk, jute, etc.

9.  The count directly expresses the size of the yarn.
A coarser yarn will have a higher number while a
finer yarn will have a lower number.
 The resultant count of the folded yarn can be
easily calculated even if the component threads
are of different counts.

10.  It is difficult to calculate the weight of the
fabric.
 Calculation of the amount of twist in the yarn
and the cloth setting are comparatively
difficult in this system.

11.  Tex system of yarn numbering is called as universal
system.
 This is a direct system of yarn numbering and is
introduced by International Standards Organization and
various organizations of textile scientists., technologists
and manufacturers.
 The merits and demerits of direct system of yarn
numbering are also applicable to universal system.

12.  This system is applicable to yarns made from
natural as well as synthetic fibres and hence
useful for replacing the several different
systems which are being used in the various
sectors of the textile industry all over the
world.

13.  Tex system can be used from fibre to yarn stage.
 The fineness of fibre can be expressed in terms
of millitex, i.e., weight of fibre in mg in one km
length and the fineness of cords, ropes and
twines, etc. are expressed in terms of Kilotex,
i.e., the weight of the material in kg in one km
length.

14.  The following instruments are generally used to determine the
count of the yarn with the wrap reel.
 The wrap reel is used to prepare the sample of length 120 yard.
1. Analytical Balance
2. Knowles Balance
3. Quadrant Balance
4. Beesley Balance
5. StubYarn Balance

15. ANALYTICAL
BALANCE

16.  In the mills, the leas of yarn are wrapped using the
wrap reel and their weight are found out using the
analytical balance.
 The weights are measured in terms of grains and the
count is calculated using the formula.
Count (Ne) = 1000/Weight of lea in grains
 For internal routine testing purposes, this may be
considered sufficiently accurate for the end in view.

17. QUADRANT
BALANCE

18.  If the sample is available with length less than
120 yards, then quadrant balance can be used to
determine its count.
 This is a direct yarn count balance.
 It consists of a quadrant scale fixed to the pillar.
 At the top of the pillar, pointer is pivoted so that
it moves over the face of the quadrant scale.

19.  A cross beam is also pivoted in the same pivot
of the pointer which has a sample hook at its
one end and a counter weight at its other
end.
 The counter weight determines the capacity
of the instrument.

20.  The quadrant scale is divided into three scales.
 The top scale can be used to find the weight per
square yard of a cloth sample in ounces.
 The middle scale is used to find the count of yarn
of length 8 yards and the third scale to find the
count of yarn of length 40 yards.

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22.  On the top of the pointer end the beam pivot, there is
a small adjusting screw, the adjustment of which
brings the pointer in line with the datum line.
 The instrument can also be levelled with a levelling
screw provided at the base of the instrument.
 To operate the instrument, it is calibrated after
levelling with the base screw.
 A counter weight marked 40 s is used for calibration.

23.  For this the counter weight is suspended from the
sample hook. If the balance is level, the pointer reads
40 s on the 40 yard scale.
 If it does not read 40 s, the pivot of the pointer is
adjusted until it reads 40 s on the 40 yards scale.
 If a sample of length 8 yards is used, its count can be
noted from the 8 yards scale and if the sample of
length 40 yards is used its count can be noted from 40
yards scale.

24. BEESLEY
BALANCE

25.  It is working on the principle of fixed weight
and fixed length system.
 It is used for assorting the count of warp and
weft yarns from a small sample of fabric.
 It consists of a pillar A which carries a cross
beam B, fulcrummed at knife edge at the
point G.

26.  At one end the cross beam is a hook E upon which the
yarn to be tested can be placed. The other end of the
beam tappers to a point C.
 When the beam is in balance, the pointer will coincide
with the datum line or the arrow mark on the beam.
 The pillar is mounted on the base.
 The whole instrument is levelled by a levelled screw at
one end of the base.

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28.  The cross beam has a small notch at the point D to
take the counter weight or rider.
 A template is also supplied with the instrument and it
can be used to measure full cotton, ½ cotton lengths,
samples of woolen and worsted yarns.
 Depending upon the material to be tested and the
quantity available., the said length can be chosen to
cut the samples of length correspondingly marked.

29.  The pointer is set directly opposite to the datum line,
with no material and counter weight in their proper
places by adjusting the levelling screw.
 The counter weight (rider) for the particular length
which is supplied with the instrument is chosen and
suspended at the notch D.
 For example, for full cotton the large rider is placed in
the notch and for ½ cotton, small rider is placed.

30.  Then, it is hung in the sample hook . The samples are
added to the sample hook, until the pointer comes in
level with the datum line.
 At that stage the threads are taken out and counted
which gives directly the count of yarn taken for
testing.
 If there are 30 threads in the sample hook at the
balanced condition, then the count of yarn is 30 s.

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