Air Flow Instruments

A sample of raw cotton is prepared in the from of a cylindrical plug and its resistance to air flow is determined at two degree of cotton of compression.Two measures of specific surface are obtained,and from them estimates of mean specific surface,mean fibre weight,and maturity are derived.Morton and Radhakrishnan investigated the performance of the Arealometer and their conclusions were as flow:
(1) The Arealometer is a portable and self-contained instrument with which it is possible in about 15 min, to measure the specific surface,the hair weight, and the maturity of a sample of raw cotton.
(2) Foe reason which remain to be more fully investigated, is it not suitable for maturity test on material that has been processed or mechanically handle.
(3) Mean specific surface and mean hair weight are determined with an accuracy that is probably not exceeded by any other method,however laborious.
(4) A geometric measure of maturity is obtained which,through not claimed to be as accurately determined as hair weight and and specific surface,seems to be no less reliable than that obtained by the much more subjective method of deconvolution counts.

The Speeder

This is another American instrument and is designed to measure specific surface quickly.Any weight of sample between 5 and 10 gm may tested.Adjustment weight is not required,there fore an increase in the speed of testing is achieved.

The Port-Ar

A portable instrument testing an 8 gm sample and producing (1) micronaire value,and (2) equivalent fibre thickness.The latter is defined as

H=2000/A
where
H= equivalent fibre thickness,and
A= Specific surface in square millimeters per cubic millimeter.