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.

 Percentage correction = 0.5 (1 - 6.48 x 104 x E x R) %
Where R = relative humidity % / 100

Rapid Regain Dryer

• Quick method.
• After drying sample is taken out for weighing
• Time should not increase 20sec from sample removal

when an external balance is used to weigh heated samples certain precautions have to be made:

1.The balance should be enclosed .

2.The time for Weighing should be exceed 20s from removal of the sample from the dryer.

3. A bouncy correction should be determined by using a dummy sample of steel wool which is weighed when cold and then reweighed after heating for a set timer (5 or 15 min).

Electrical Method

Shirley moisture Meter

• Principle: Since electrical property of fibre changes with the moisture, measurement of resistance can be used to give indirect method of measuring regain.
• DISADVANTAGE: Dyeing and chemical treatments alter the electrical properties of the sample due to which there is a need to recalibrate it.