WCO Explanatory Notes reproduced for reference. © World Customs Organization. Verify against official WCO publication.
84.11 - Turbo-jets, turbo-propellers and other gas turbines (+). 8411.11 - - Of a thrust not exceeding 25 kN 8411.12 - - Of a thrust exceeding 25 kN 8411.21 - - Of a power not exceeding 1,100 kW 8411.22 - - Of a power exceeding 1,100 kW - Other gas turbines : 8411.81 - - Of a power not exceeding 5,000 kW 8411.82 - - Of a power exceeding 5,000 k W - Parts : 8411.9 1 - - Of turbo-j ets or turbo-propellers 8411.99 - - Other This heading covers turbo-jets, turbo-propellers and other gas turbines. The turbines of this heading are, in general, internal combustion engines which do not usually require any external source of heat as does, for example, a steam turbine. (A) TURBOJETS A turbo-jet consists of a compressor, a combustion system, a turbine and a nozzle, which is a convergent duct placed in the exhaust pipe. The hot pressurised gas exiting from the turbine is converted to a hi h velocity gas stream by the nozzle. The reaction of this gas stream actin m the engine provi es the motive force which may be used to ower aircraft. In its sim lest o On the compressor and turbine are accommodated on a single s aft. In more corn lex esigns the compressor is made in two parts (a two spool compressor) in which the spoo of each part is driven by its own turbine through concentric shafting. Another variation is to add a ducted fan usually at the inlet to the corn ressor and drive this either by a thrd turbine or connect it to the first compressor spool. The an acts in the nature of a ducted propeller, most of its ou ut bypassing the compressor and turbine and joining the exhaust jet to provide extra thrust. $is version is sometimes called a " bypass fan jet ". d R P B B F So-called " after-burning " ap liances are auxiliary units for mounting in series with certain turbo-jet engines in order to oost their power output for short periods. These appliances have their own he1 supply and utilise the excess oxygen in the gases issuing from the turbo-jet. E (B) TURBO-PROPELLERS Such engines are similar to turbo-jets, but have a further turbine downstream of the compressor turbine, which is coupled to a conventional propeller such as is used on piston en ined aircraft. This latter turbine is sometimes referred to as a " free turbine ", meaning t%a t it is not mechanically coupled to the compressor and compressor turbine shaft. Thus most of the hot pressurised gas leaving the compressor turbine is converted into shaft ower by the free turbine Instead of being expanded in a nozzle as is the case in turbo-jets. some cases, the gases leaving the £tee turbine may be expanded in a nozzle to provide auxiliary jet power and assist the propeller. R (C) OTIIER GAS TURBINES This group includes industrial gas-turbine units which are either specifically designed for industrial use or adapt turbo-jets or turbo-propeller units for uses other than providing motive power for aircraft. There are two types of cycles : (1) The simple cycle, in which air is ingested and compressed by the compressor, heated in the combustion system and passed through the turbine, finally exhausting to the atmosphere. and passed through the air and is then passed to the The d g a s mixture hot gas side of the regenerator and (2) The re enerative cycle, in pipes ogf a regenerator. The combustion s stem where asses tbroud the turbine Enally to the atmosphere. There are two types of designs : (a) The single-shaft gas turbine unit, in which the compressor and turbine are built on a single shaft, the turbine providing power to rotate the corn ressor and to drive rotating machinery through a coupling. This type of drive is most e ective for constant speed applications such as electrical power generation. d (b) The two-shaft gas turbine unit, in which the compressor, combustion system and compressor turbine are accommodated in one unit generally called a as generator, whilst a second turbine on a se arate shaft receives the heated and pressurise gas fiom the exhaust of the gas generator. & i s second turbine known as the power turbine is coupled to a driven unit, such as a compressor or pump. Two-shaft gas turbines are normally applied where load demand variations require a range of power and rotational speed fiom the gas turbine. f These gas turbines are used for marine craft and locomotives, for electrical power generation, and for mechanical drives in the oil and gas, pipeline and petrochemical industries. This grou also includes other gas turbines without a combustion chamber, comprising simply a stator ancf rotor and which use energy from gases provided by other machines or appliances (e.g., gas r r a t o r s , diesel engines, fiee-plston generators) and compressed air or other compresse gas turbines. PARTS Sub'ect to the general provisions regardin the classification of parts (see the General Exp anatory Note to Sechon XVI),parts of t e en ines and motors of this heading are also classified here (e.g., gas turbine rotors, combustion &ambers and vents forjet engines, parts of turbo-jet engines (stator rings, with or without blades, rotor discs or wheels, w t h or without fins, blades and &), fuel feed regulators, fuel nozzles). 8,
Subheading Explanatory Note. Subheadings 8411.11 and 8411.12 Thrust is to be taken to mean the roduct of the exhaust mass flow per second and the difference between the exhaust velocity and the air in et velocity. P -
Notes. 1.- This Chapter does not cover : (a) Millstones, grindstones or other articles of Chapter 68; (b) Machinery or appliances (for example, pumps) of ceramic material and ceramic parts of machinery or appliances of any material (Chapter 69); (c) Laboratory glassware (heading 70.17); machinery, appliances or other articles for technical uses or parts thereof, of glass (heading 70.19 or 70.20); (d) Articles of heading 73.21 or 73.22 or similar articles of other base metals (Chapters 74 to 76 or 78 to 81); (e) Vacuum cleaners of heading 85.08; (f) Electro-mechanical domestic appliances of heading 85.09; digital cameras of heading 85.25; (g) Radiators for the articles of Section XVII; or (h) Hand-operated mechanical floor sweepers, not motorised (heading 96.03). 2.- Subject to the operation of Note 3 to Section XVI and subject to Note 11 to this Chapter, a machine or appliance which answers to a description in one or more of the headings 84.01 to 84.24, or heading 84.86 and at the same time to a description in one or more of the headings 84.25 to 84.80 is to be classified under the appropriate heading of the former group or under heading 84.86, as the case may be, and not the latter group. (A) Heading 84.19 does not, however, cover : (i) Germination plant, incubators or brooders (heading 84.36); (ii) Grain dampening machines (heading 84.37); (iii) Diffusing apparatus for sugar juice extraction (heading 84.38); (iv) Machinery for the heat-treatment of textile yarns, fabrics or made up textile articles (heading 84.51); or (v) Machinery, plant or laboratory equipment designed for a mechanical operation, in which a change of temperature, even if necessary, is subsidiary. (B) Heading 84.22 does not cover : (i) Sewing machines for closing bags or similar containers (heading 84.52); or (ii) Office machinery of heading 84.72. (C) Heading 84.24 does not cover : (i) Ink-jet printing machines (heading 84.43); or (ii) Water-jet cutting machines (heading 84.56). 3.- A machine-tool for working any material which answers to a description in heading 84.56 and at the same time to a description in heading 84.57, 84.58, 84.59, 84.60, 84.61, 84.64 or 84.65 is to be classified in heading 84.56. 4.- Heading 84.57 applies only to machine-tools for working metal, other than lathes (including turning centres), which can carry out different types of machining operations either : (a) by automatic tool change from a magazine or the like in conformity with a machining programme (machining centres), (b) by the automatic use, simultaneously or sequentially, of different unit heads working on a fixed position workpiece (unit construction machines, single station), or (c) by the automatic transfer of the workpiece to different unit heads (multi-station transfer machines). 5.- For the purposes of heading 84.62, a “slitting line” for flat products is a processing line composed of an uncoiler, a coil flattener, a slitter and a recoiler. A “cut-to-length line” for flat products is a processing line composed of an uncoiler, a coil flattener, and a shear. 6.- (A) For the purposes of heading 84.71, the expression “automatic data processing machines” means machines capable of : (i) Storing the processing program or programs and at least the data immediately necessary for the execution of the program; (ii) Being freely programmed in accordance with the requirements of the user; (iii) Performing arithmetical computations specified by the user; and (iv) Executing, without human intervention, a processing program which requires them to modify their execution, by logical decision during the processing run. (B) Automatic data processing machines may be in the form of systems consisting of a variable number of separate units. (C) Subject to paragraphs (D) and (E) below, a unit is to be regarded as being part of an automatic data processing system if it meets all of the following conditions : (i) It is of a kind solely or principally used in an automatic data processing system; (ii) It is connectable to the central processing unit either directly or through one or more other units; and (iii) It is able to accept or deliver data in a form (codes or signals) which can be used by the system. Separately presented units of an automatic data processing machine are to be classified in heading 84.71. However, keyboards, X-Y co-ordinate input devices and disk storage units which satisfy the conditions of paragraphs (C) (ii) and (C) (iii) above, are in all cases to be classified as units of heading 84.71. (D) Heading 84.71 does not cover the following when presented separately, even if they meet all of the conditions set forth in Note 6 (C) above : (i) Printers, copying machines, facsimile machines, whether or not combined; (ii) Apparatus for the transmission or reception of voice, images or other data, including apparatus for communication in a wired or wireless network (such as a local or wide area network); (iii) Loudspeakers and microphones; (iv) Television cameras, digital cameras and video camera recorders; (v) Monitors and projectors, not incorporating television reception apparatus. (E) Machines incorporating or working in conjunction with an automatic data processing machine and performing a specific function other than data processing are to be classified in the headings appropriate to their respective functions or, failing that, in residual headings. 7.- Heading 84.82 applies, inter alia, to polished steel balls, the maximum and minimum diameters of which do not differ from the nominal diameter by more than 1 % or by more than 0.05 mm, whichever is less. Other steel balls are to be classified in heading 73.26. 8.- A machine which is used for more than one purpose is, for the purposes of classification, to be treated as if its principal purpose were its sole purpose. Subject to Note 2 to this Chapter and Note 3 to Section XVI, a machine the principal purpose of which is not described in any heading or for which no one purpose is the principal purpose is, unless the context otherwise requires, to be classified in heading 84.79. Heading 84.79 also covers machines for making rope or cable (for example, stranding, twisting or cabling machines) from metal wire, textile yarn or any other material or from a combination of such materials. 9.- For the purposes of heading 84.70, the term “pocket-size” applies only to machines the dimensions of which do not exceed 170 mm x 100 mm x 45 mm. 10.- For the purposes of heading 84.85, the expression “additive manufacturing” (also referred to as 3D printing) means the formation of physical objects, based on a digital model, by the successive addition and layering, and consolidation and solidification, of material (for example, metal, plastics or ceramics). Subject to Note 1 to Section XVI and Note 1 to Chapter 84, machines answering to the description in heading 84.85 are to be classified in that heading and in no other heading of the Nomenclature. 11.- (A) Notes 12 (a) and 12 (b) to Chapter 85 also apply with respect to the expressions “semiconductor devices” and “electronic integrated circuits”, respectively, as used in this Note and in heading 84.86. However, for the purposes of this Note and of heading 84.86, the expression “semiconductor devices” also covers photosensitive semiconductor devices and light-emitting diodes (LED). (B) For the purposes of this Note and of heading 84.86, the expression “manufacture of flat panel displays” covers the fabrication of substrates into a flat panel. It does not cover the manufacture of glass or the assembly of printed circuit boards or other electronic components onto the flat panel. The expression “flat panel display” does not cover cathode-ray tube technology. (C) Heading 84.86 also includes machines and apparatus solely or principally of a kind used for : (i) the manufacture or repair of masks and reticles; (ii) assembling semiconductor devices or electronic integrated circuits; (iii) lifting, handling, loading or unloading of boules, wafers, semiconductor devices, electronic integrated circuits and flat panel displays. (D) Subject to Note 1 to Section XVI and Note 1 to Chapter 84, machines and apparatus answering to the description in heading 84.86 are to be classified in that heading and in no other heading of the Nomenclature. Subheading Notes. 1.- For the purposes of subheading 8465.20, the term “machining centres” applies only to machine-tools for working wood, cork, bone, hard rubber, hard plastics or similar hard materials, which can carry out different types of machining operations by automatic tool change from a magazine or the like in conformity with a machining programme. 2.- For the purposes of subheading 8471.49, the term “systems” means automatic data processing machines whose units satisfy the conditions laid down in Note 6 (C) to Chapter 84 and which comprise at least a central processing unit, one input unit (for example, a keyboard or a scanner), and one output unit (for example, a visual display unit or a printer). 3.- For the purposes of subheading 8481.20, the expression “valves for oleohydraulic or pneumatic transmissions” means valves which are used specifically in the transmission of “fluid power” in a hydraulic or pneumatic system, where the energy source is supplied in the form of pressurised fluids (liquid or gas). These valves may be of any type (for example, pressure-reducing type, check type). Subheading 8481.20 takes precedence over all other subheadings of heading 84.81. 4.- Subheading 8482.40 applies only to bearings with cylindrical rollers of a uniform diameter not exceeding 5 mm and having a length which is at least three times the diameter. The ends of the rollers may be rounded.