F01C: Wool Fibre Diameter - Airflow - Sliver

AWTA TEST CODE

:

F01C

OTHER NAMES

:

TEST METHODS

:

IWTO 6
BS 3183
ASTM D1282

IMAGES

:

Airflow Test Apparatus

APPLICATION

:

This method is applicable to non-medullated wool fibres in sliver form, free from vegetable matter and containing not more than 1.0 percent of dichloromethane soluble extractable matter when tested. It is also applicable to oil combed slivers after cleaning with dichloromethane. Note that the method is less accurate than the projection microscope method when used for lambswool, wool which is appreciably medullated and for some heavily dyed wool fibres.

PRINCIPLE

:

A specified weight of wool is compressed to a constant volume in a cylindrical chamber with perforated ends. A current of air is passed through the compressed fibre and the mean fibre diameter derived from the air flow through the specimen at constant pressure differential.

SAMPLES REQUIRED FOR TESTING

:

The laboratory sample usually consists of 1 or 2 short lengths of sliver, drawn from the lot in such a way as to be representative of the package or consignment. The test specimens are 2.5g each depending on the type of apparatus used. Minimum total sample weight required 12g.

INTERPRETATION

:

The estimate of mean fibre diameter obtained by the air flow method is d(1+c2), where d is the mean fibre diameter given by the projection microscope and c is the fractional coefficient of variation. Since c is usually comparatively small for unblended slivers, it is usual to calibrate the instrument directly in terms of d. The mean fibre diameter obtained by air flow methods should thus be equivalent to that obtained by projection microscope. NOTE THAT THE AIR FLOW METHOD DOES NOT GIVE AN ESTIMATE OF VARIATION OF DIAMETER.

SERVICE TARGET

:

5 days

COST

:

See current fees list