Special lamps for use in laboratories

85.39 - Electric filament or discharge lamps, including sealed beam lamp units and ultraviolet or infra-red lamps; arc-lamps. 8539.10 - Sealedbeamlamp units - Other filament lamps, excluding ultra-violet or infka-red lamps : - - Tungsten halogen 8539.22 - - Other, of a power not exceeding 200 W and for a voltage exceeding 100 V 8539.29 - - Other - Discharge lamps, other than ultra-violet lamps : 8539.3 1 - - Fluorescent, hot cathode 8539.32 - - Mercury or sodium vapour lamps; metal halide lamps 8539.39 - - Other - Ultra-violet or infra-red lamps; arc-lamps : 8539.21 Electric light lamps consist of glass or quartz containers, of various sha es, containing the elements for converting electncal energy into light rays (inc uding infra-red or ultra-vlo et rays). F neces"r The headin covers all electric light lamps, whether or not specially designed for particular uses (including 1ashlight discharge lamps). The heading covers filament lamps, gas or vapour discharge lamps and arc-lamps. (A) SEALED BEAM LAMP UNITS Sealed beam lam units are sometimes designed for incorporation in the bodywork of cars; they consist of a ens and reflector and a filament sealed within a gas-filled or vacuum-type lamp. P (B) OTHER FILAMENT LAMPS, EXCLUDING ULTRA-VIOLET OR INFRA-RED LAMPS (see Part 0)) The light is produced by a filament (metal or carbon) which is heated to incandescence by the passage of an electric current, the glass envelope (sometimes coloured) belng either evacuated or filled with an inert gas under low pressure; in the base, which may be of the screw or bayonet type for fixing in the lamp-holder, are the necessary electrical contacts. f' These lamps are of various sha es, e.g., spherical (with or without a neck ; pear or onion shaped; flame shaped; tubular Ptraight or curved); special fancy shapes or illuminations, decorations, Christmas trees, etc. This group also covers halogen lamps. (C) DISCHARGE LAMPS, OTHER THAN ULTRA-VIOLET LAMPS (see Part (D)) These consist of a lass envelope (usually tubular) or a quartz envelope (usually in an outer envelo e of glass), furnished w ~ t helectrodes and containing, under low pressure, either a gas which ecomes luminous under the influence of an electric discharge or a substance which gives off a vapour having similar properties; certain lamps may contain both a gas and a vapour producing substance. Some lamps have valves for the removal of compounds resultin from the action of the gas on the electrodes; others may be vacuum acketed or water cwlecf In some cases the internal wall of the lamps is coated with special su stances which transform the ultraviolet rays into visible light thus mcreasin the efficiency of the lamp (fluorescent lamps). Some lamps operate on high voltages, others on ow. ! B i The principal lamps of this kind include : (1) Gas dischar e tubes containing ases such as neon, helium, argon, nitrogen or carbon f i dioxide, inc uding flashing disc arge lamps used for photography or stroboscopic examination. (2) Sodium vapour lamps. (3) Mercury vapour lamps. (4) Gas filled dual lamps, in which the light is produced both by an incandescent filament and a gas discharge. (5) Metal halide lamps. (6) Xenon and alphanumeric tubes. (7) Spectral discharge and glow discharge lamps. These lamps are used for man p oses, e.g., domestic lighting; street lighting; office, factory, shop, etc., lighting; lighting o mac ines; and lighting for decorative or public1 purposes. The heading includes simple straight or curved tubes, and tubes in various comp ex forms (e.g., scrolls, letters, figures and stars). i! "E 'Y (D) TJLTRA-VIOLET AND INFRA-RED LAMPS Ultra-violet lamps are used for medical, laboratory, germicidal or other purposes. They usually consist of a fused quartz tubc containing mcrc ; they arc sometil~iesenclosed in a1 outer envelope of glass. Some are known as black ight lamps (e.g., those used for theatrical purposes). Infra-red lamps are filament lamps specially desi ned to produce infra-red rays. In many cases the interior of the lamp is coppered or silvered to o m a reflector. They are used, for example, for medical purposes or as a source of heat in industry. (E) ARC-LAMPS In lam s of this kind the light is emitted by an arc, or by an arc and by the incandescence of one or bot of the electrodes between which the arc is maintained. These electrodes are generally of carbon or tungsten. Some lamps have an automatic device to bring the electrodes close together in order to strlke the arc, and subsequently to maintain them at the correct distance apart in spite of the progressive using up of electrodes. Lamps designed for AC working have supplementary electrodes for starting p oses. In open arc-lamps the arc burns in free air; in others it is in a glass envelope with su~tabe baffles communicating with the free air. R "P It should be noted that arc-lamps are corn lex apparatus, and are not merely simple lighting elements as is the case of the other goods o this heading. ? PARTS Sub'ect to the general provisions regarding the classification of parts (see the General Exp anatory Note to Section XVI), parts of the goods of this heading are also classified here. They include : I (1) Bases for incandescent and discharge electric lamps and bulbs. (2) Metal electrodes for discharge lamps and tubes. The heading excludes (a) Glass envelopes, and glass parts having the essential character thereof (e.g., spotlight bulb reflectors) for lamps (heading 70.11). @) Resistance lamps with carbon filaments and variable lamps with iron filaments in hydrogen (heading 85.33). (c) Automatic thermo-electric switches (starters) for starting fluorescent lamps (beading 85.36). (d) Themionic valves and tubes (heading 85.40). (e) Luminescent diodes (heading 85.41). (f) Electro-luminescent devices, enerally in strips, plates or panels, and based on electro-luminescent substances (e.g., zinc sulphideyplaced between two layers of conductive material (herding 85.43). (g) Arc-lamp carbons and carbon filaments (heading 85.45).