Determine the micronaire value of given cotton sample by air blow method. Convert the result into S.I unit and give a suitable rating to the fiber sample

Machine Used : Micronaire tester, Weighing machine

Objective:- It is use to check the micronaire value, fiber fineness as well as maturity of cotton  fiber.

Theory:- This is indirect method of measuring fiber fineness which is based on the fact that the air flow at a given pressure difference through a uniformity distributed mass of fibers is determined by the total area of a fibers is proportional to its diameter because the air flow varies with pressure difference it is ratio of air flow to differential pressure that is determined by the fiber diameter.

Procedure :-

1. Weigh accurately 324 grams of sample tested with a weighing balance.
2. Keep the air pressure exactly as 2.5 bar before calibration.
3. Then process the calibration switch by holding and take the adjustable knob clockwise, anti-clock wise until the top of the indicating float in the glass tube rises to the calibration mark.
4. Lock the adjustable knob by pushing down and release the calibration switch now instrument is ready for testing.
5. Now place the sample in cotton chamber and lock with compression plunger.
6. Move operating handle right, depress and release once, the "cal" bottom that note the value indicated by the float and you will get the micronaire value.
7. Take more than two reading, so that the exact micronaire value is the average of those reading.

Precaution :-

1.   DO not exceeds or increse the input pressure above 2.5 bar.
2. Take the exact weight of the sample is 324 gram.
3. Before taking the observation the callibration should be done.

Practical Importance :-

• Micronaire is a measure of the air permeability of compressed cotton fibre. It is after used as an indication of fibre fineness and maturity.
• fiber fineness and maturity are critical for fiber processing as well as fiber quality cotton's micronaire measurement impact the following:- 

1. Processing Waste
2. Spinning performance
3. Yarn and fabric quality 
4. Dyed fabric appearence

Result :-

Hence the micronaire value of cotton is 2.5 mic, which means the cotton fiber is very fine.

Technical Specification:-   

• Pressure :- 2.54 bar.
• Air capacity :- 50psi (4bar)
• Measuring accuracy :- 2.2 to 8.0 mic