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OPERATION
Calculator scales
tested slide the scale into position see Fig.
If a scale is available for the substance to be
calibration data sheet.
1.1. If there is no scale available then select the appropriate
following sections give the general method of operating the instrument. Detailed
calibration data supplied for each
procedures that apply to particular materials are given in the
group of substances.
2.3 PREPARATION OF SAMPLE
Granular or powdery substances
The instrument may be used in two ways:
On whole grain
(a)
On the flour or meal produced by coarse grinding.
(b)
Tests on unground granular substances are strongly influenced by the surface moisture.
Tests on whole grains of wheat indicate substantially the bran moisture. For this reason it is
advisable to test the sample both whole and ground, to give an indication of the moisture
distribution as well as its average value.
The fineness of grinding is not important but the loss of moisture which may occur,
especially with damp samples, must be minimised. Therefore avoid very fine grinding. After
grinding, flush out the grinder with the sample to be tested and discard the first ground sample.
Fibrous material
In general the procedure is the same as for granular materials.
The cavity for the test cell should be approximately half filled with the specimen until
packed uniformly, pressing the specimen down in much the same manner as filling a pipe. After
the test the compressed plug should be about 1/16 inch thick.
2.4 LOADING THE COMPRESSION CELL
The following description may appear complicated because each detail is mentioned but
the procedure will be found quite simple and convenient.
46882-171 D
Apr. 92
8
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