The document discusses the impact of actual regain on the count and strength of textiles, providing formulas for calculating corrected yarn count based on standard regain for both indirect and direct yarn numbering systems. It also outlines methods to correlate yarn count and strength under humidity changes, including various measuring techniques and instruments for assessing relative humidity. The document further details specific instruments such as hair hygrometers and conditioning ovens used in the measurement process.

1. With the changes in the actual regain of textiles, there are changes
in the weight of the material which affect the count and strength of
material. If the actual regain of the specimen in known, it is possible to
calculate the count and strength corrected in the standard regain.
Corrected Count
The count of yarn corrected to the standard regain is known as
corrected count of the yarn.
If N is the count of the yarn at the actual regain Ra (Regain at the
time of testing) and Rs, is the standard regain, then
N (100 + Ra)
Corrected count Nc = ------------------
100+Rs
The above formula is used for indirect system of yarn numbering.
For direct system of the yarn count, the following formula is used.
N (100+Rs)
Corrected count Nc = ------------------
100 + Ra
CORRELATION OF YARN COUNT AND STRENGTH
FOR HUMIDITY CHANGES

2. 1. Gravimetric Method
2. Chemical Method
3. Dew point Method
Methods to measure the Relative Humidity
1. Hair hygrometer or Thermo Hygrograph
2. Electrolytic Hygrometer
3. Wet and dry bulb Hygrometer
Instruments Used to measure Relative Humidity

3. Absorption curves of various materials

4. WET AND DRY BULB HYGROMTER
WET AND DRY BULB HYGROMTER

5. Conditioning Oven

6. Thermo Hygrometer
A - chart B – Pen arm
C – Pen D – Bi-Metalical helical coil
E – Band of human hair
E
D

7. Sling Hygrometer