The following instrument is 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 Yards.
Analytical Balance.
Knowles Balance.
Quadrant Balance.
Beesley Balance.
Stubb yarn Balance.
Analytical Balance:
In the mills, the leas of yarn are wrapped using the wrap reel and their weight is 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 a lea in grains
For the internal routine testing purpose, this may be considered sufficiently accurate for the end in view.
1 grain = 0.0647989 grams.
Knowles Balance:
This is a direct reading yarn count balance. It is used when the sample is available in large quantities such as hank, ring cops, etc. so that leas of 120 yards can be wrapped using the wrap reel.
Knowles Balance is similar to the ordinary physical balance as shown in the above fig. Behind the beam, the balance, a hexagonal scale, or a rectangular board is mounted. The principle used in this instrument is the fixed weight and fixed-length system i.e., principles of the moment of balancing length. The hexagonal scale or the rectangular board is mounted on a pillar, behind the main pillar of the balance. The faces of the hexagonal scale are lettered from A to F and each face is calibrated to cover different each range of count from coarse to fine. In the case of a rectangular board, seven scales are calibrated and are lettered from A to G. Anyone face of the rectangular board can be brought to the level of the beam by turning a knob in front of the balance. Two counterweights are provided with the instrument, one is circular and the other is rectangular and are marked with the letters A, B, C, D, E, F, and G. The circular weight is placed on the left-hand pane of the balance and the rectangular weight on the beam. The sample of the yarn in the lea form is placed on the right-hand pane.
The count of the yarn is approximately assumed and depending upon the count, the face of the hexagonal scale is selected for example: if the count of the yarn is assumed as the 30s then B face is selected. Which has a range of counts from 20s to 40s to find the exact count of the yarn. In the case of the rectangular board, the scale the rectangular board the scale which has that count is bought in level with the beam of the balance by turning the knob. Then the circular weight with the mark similar to that on the scale, in this case, B is placed on the left beam. Then a sample of lea is placed on the right-hand pane and the position of the rectangular weight is adjusted on the beam until the beam is balanced. The count of the yarn is then read off directly from the scale the value opposite a line marked in the center of the rectangular weight.
Quadrant Balance:
If the sample is available with a length less than 120 yards then Quadrant Balance can be used to determine its count.
This is a direct reading yarn count balance and it consists of a quadrant scale fixed to a pillar as shown in fig. At the top of the pillar, the pointer is pivoted so that it moves over the face of the quadrant scale. A crossbeam is also pivoted n the same pivot of the pointer which has a sample hook at its one end and a counterweight at its other end. The counterweight determines the capacity of the instrument. The addition of any weight to the sample hook makes the pointer move Infront of the scale.
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 to find the counter of yarn of length 8 yards, and the third scale to find the count of yarn of length 40 yards.
On the top of the pointer and 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 leveled with a leveling screw provided at the base of the instrument.
To operate the instrument, it is calibrated after leveling with the base screw. A counterweight marked the 40s is used for calibration for this the counterweight is suspended from the sample hook. If the balance is level the pointer reads the 40s on the 40 yards scale. If it does not read the 40s the pivot of the pointer is adjusted until it reads 40s on the 40yard 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 the 40 yards scale.
Beesley balance:
Click here to find the full article on Beesley Balance.
Stubb Yarn Balance:
It is also called pocket balance and is used to determine the count of warp and weft yarns taken from a small piece of fabric. The principle is the fixed weight and fixed-length system i.e., the number of fixed weights gives the count of the yarn.
It consists of a pillar at the top of which a beam is pivoted on a knife-edge as shown in fig. A sample hook is suspended at one end of the beam and at its other end weight hooks are suspended. A template is used to cut the yarn to a fixed length. Different weight hooks are to be used when different materials are being tested.
Depending upon the material the weight hook is selected and suspended at one side of the beam and the yarn samples are added to the sample hook at its other side to bring the beam to a balanced position. The number of threads used to balance the beam gives the count of the yarn taken for the test.
This is a very simple instrument and there is no mechanism that goes out of order. This can be used in the testing and weaving laboratories to determine the count of warp and weft yarns during the cloth analysis.
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