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.

Testing Room Atmosphere

The Control Of The Testing Room Atmosphere

• The THERMOSTATS and HYGROMETER CONTROL VALVES operates by compressed air.
• The air input to the conditioning plant may come from outside or be recirculated air, or a mixture of both.
• In all instance it is filtered before heating and conditioning.
• A fan blows the conditioned air in to the laboratory through special ducts with lowered outlets in the ceiling.
• All the windows are double glazed used to prevent unwanted air coming in from the corridor when people pass in and out of the laboratory.
• Automatic two "towers" are used, one for adding moisture and one for subtracting moisture from the air.

Measurement of Moisture Regain

By oven dry method (Direct)

• It contains the fiber sample in a mesh container.
• The container is suspended inside the oven from one pan of balance, the mechanism of which is outside the oven.
• This ensures that the weight of the sample can be monitored without disturbing the system.

ADVANTAGE

• All the weighing is carried out inside the oven.
• The use of the conditioning oven to dry a sample is correct standard procedure; any other method of sample drying has to be checked for accuracy against it.
• The use of the conditioning oven to dry a sample is correct standard procedure; any other method of sample drying has to be checked for accuracy against it.