Elec tric heating resistors

85.45 Carbon electrodes, carbon brushes, lam carbons, batte carbons and other articles of graphite or other carbon, wit; or without metX9 of a kind used for electrical purposes. - Electrodes : - - Of a kind used for furnaces 8545.19 - - Other 8545.20 - Brushes 8545.90 - Other 8545.11 This heading covers all articles of aphite or other carbon which are recognisable by their shape, dimensions or otherwise, as g i n g for electrical purposes, whether or not they contain metal. In general, these articles are obtained by the extrusion or by the moulding (usually under pressure) and heat-treatment of a corn osition which, in addition to its basic constituent (natural carbon, carbon black, gas carbon, co$e, natural or artificial graphite, etc.) and the necessary binders (pitch, tar, etc.), may also contain other substances such as metallic powders. Tn some cases the articles of this heading may be coated electrolytically or by spraying (e.~., with copper) to increase their conductivity and decrease their rate of wear. They remain classified here even if fitted with eyelets, terminals or other means of connection. The heading includes : (A) Carbon electrodes for furnaces. r These are general1 in the form of cylinders or rods, and are sometimes threaded or tapped at the ends to enab e them to be screwed into position. (B) Carbon welding electrodes. These are generally in the form of rods. (C) Carbon electrodes for electrolysis. These may be in the form of plates, bars (including bars of triangular cross-section), cylinders, etc. They are designed to be mounted or suspended in electrolysis baths, and may be furnished with fittings for this purpose such as hooks or rings. Certain es may be pierced with holes or grooved to facilitate the removal of gases formed on them wing use. 'YS (D) Carbon brushes. These are used as sliding contacts for generators, motors, etc., as current-collectors for electric locomotives, etc. Though some may be made by direct moulding, the large majority are cut from the " carbon " blocks or plates described in Ex lanatory Note to heading 38.01. They are all made very accurately to size and the aces are carellly machined to tolerances of a few hundredths of a millimetre. They can therefore be indentified by their sizes, shapes, and highly-finished surfaces; in many cases, they may also be wholly or partly metal-coated or be fitted with connectors (brackets, cables, terminals, springs, etc.). P Such carbon brushes may be of any of the grades described in Explanatory Note to heading 38.01, or may contain silver. This heading does not, however, include metal brushes coated with an external lubricating layer of graphite (heading 85.35 or 85.36). Brush holders (whether or not complete with their brushes) are classified as parts of machines (e.g., heading 85.03). (E) Arc-lamp or other lamp carbons. Arc-lamp carbons are usually in the form of rods or pencils; they sometimes have a core of special composition to improve arc stability and to provide high intensity light output, or to give the flame a special colour. The heading also covers carbon filaments for electrical resistance lamps. (F) Battery carbons. According to the type of battery for which they are intended, these may be in the form of rods, plates, tubes, etc. (G) Carbon parts of microphones. These may consist of discs or other identifiable parts. (H) Other articles of graphite or other carbon, such as : (1) Connecting pieces (nipples) for joining together h a c e carbons. (2) Anodes, grids and screens for rectifying valves. (3) Heating resistors, in the form of rods, bars, etc., for various types of heating apparatus. (4) Resistance discs and plates for automatic voltage regulators. (5) Other contacts or electrodes of carbon. The heading also excludes : (a) Graphite or other carbon in the form of powders or granules (Chapter 38). (b) Carbon resistors (heading 85.33). -