HEADING 90.16 - BALANCES OF A SENSITIVITY OF 5 cg OR BETTER WITH OR WITHOUT WEIGHTS.

38 COMMODITIES

This heading covers balances of all types provided their sensitivity is 5 cg or better. Weights presented with such balances fall in this heading but weights presented separately even if made of precious metal are excluded (heading 84.23).

Many of the balances of this heading are designed for precision measurement and are made of non-corrosive metal or of light alloys with knife-edges bearings and planes of agate. To protect the balances from air currents and dust they may be enclosed in a glass or plastics case or built in a cabinet consisting chiefly of glass or plastics; they are then manipulated by handles and other devices outside the cabinet. They may also be fitted with an optical device (e.g. magnifying lens) be artificially illuminated to assist in reading the scale or be fitted with levelling devices (tripod adjustable screws spirit-level etc.). n certain torsion balances the weight to be measured is counterbalanced by the  torsion of a wire.

Certain electronic balances are used in a vacuum or under controlled pressure to record the variations in weight of substances submitted to special treatment (heating cooling the action of a gas vacuum treatment exposure to light etc.). Weight variations are measured by recording the current passing through a magnetic balancing coil.

The heading includes :

(1) Analytical balances (e.g. microchemical balances microbalances aperiodic analytical balances) used mainly in quantitative chemical analysis.

(2) Assay balances used in the assaying of precious metals.

(3) Balances for precious stones graduated in carats.

(4) Chemists' balances yarn balances samples balances (used to establish the weight of paper textile fabrics etc.).

(5) Hydrostatic (or specific gravity) balances for ascertaining the specific gravity of liquids or solids.

PARTS AND ACCESSORIES

Subject to the provisions of Notes 1 and 2 to this Chapter (see the GeneralExplanatory Note) parts  and accessories (including mounted or unmounted agate knife-edges bearings and planes)  identifiable as being suitable for use solely or principally with the balances of this heading are also classified here (for example beams trays cabinets dials tripods swing dampers).

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Balances of a sensitivity poorer than 5 cg are excluded (heading 84.23).

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