Introduction
Correct mechanical sampling is an operation that requires most careful attention. Emphasis cannot therefore be too strongly laid on the necessity of obtaining a properly representative sample of milled products. Careless or inaccurate mechanical sampling lead to misunderstanding and unwarranted financial adjustments.
The procedures given in this standard are recognized as good practice and it is strongly recommended that they be followed whenever practicable. It is difficult to lay down fixed rules to be followed in every case, and particular circumstances may render some modification of the method desirable, for example if it is desired to check the uniformity of a consignment by the examination of individual primary samples.
In certain areas there are widely recognized trade associations which prescribe rules for the sampling procedures to be used in contracts under their auspices. In no case will be methods described in this Standard override the rules laid down in such contracts, or the rules of official inspecting organizations.
Definitions
For the purpose of this standard, the following definitions apply:
- Consignment: The quantity of product dispatched or received at one time and covered by a particular contract or shipping document. It may be composed of one or more lots.
- Lot: A part of a consignment or a consignment, moving past the sampling point during a stated period of time, with presumed uniform characteristics and to which a given scheme of investigation can be applied.
- Primary sample: A small quantity of product taken from the lot at a single point in time or during a stated short period of time. A series of primary samples should be taken at a number of points in time or during a series of short periods of time such that, when bulked, they will be representative of the lot.
- Bulk sample: The quantity of product formed by combining and mixing the primary samples taken from a specific lot.
- Final lot sample: A sample representing the quality of the lot, obtained by reduction of the bulk sample.
- Laboratory sample: The quantity of product obtained by careful subdivision of the final lot sample and intended for analysis or other examination.
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