Of a power exceeding 10,000 kW

84.10 - Hydraulic turbines, water wheels, and regulators therefor. - Hydraulic turbines and water wheels : 8410.11 - - Of a power not exceeding 1,000 kW 8410.12 - - Of a power exceeding 1,000 kW but not exceeding 10,000 k W 8410.13 - - Of a power exceeding 10,000 kW 8410.90 - Parts, including regulators This heading covers hydraulic turbines and water wheels which can, by themselves, transform into motive power the energy possessed by moving liquids or liquids under pressure (e.g., the flow or fall of water; pressure of water, oil or special fluids). These en nes or motors may thus operate b directing a moving mass of water on to paddles, blades or elicoidal elements fitted to a wheer f! (A) HYDRAULIC TURBINES Hydraulic turbines consist of a rotor encased in a stator which directs jets of water on to the blades, etc., of the rotor. Hydraulic turbines are mainly of three types : (1) Pelton ye, for high-pressure water su ply of~comparativelysmall volume. The rotor with a large number of cups. The s consists o a wheel fitted radially aroun ~ t periphery stator consists merely of a strong casing with one or more jets directing the water tangentially on to the cups. (2) Francis type, for medium or low water ressure at large volume. These comprise a onepiece cast steel rotor with large, fixed heEcoida1 blades, and a stator consisting of conduit tubing, usually spiralled, with large, variable angle guide blades ensuring a radial flow of water around the whole periphery of the rotor, and an axial water-outlet. (3) Kaplan e, for low pressure supplies. These are turbines, closely resembling those described a ove, both the stator and rotor having adjustable angle blades. The main use of hydraulic turbines is in hydro-electric installations. (B) WATER WHEELS These very simple en 'nes consist of a large wheel fitted with flat or hollow paddles of wood or metal around its perip ery, the axle of the wheel bein generally fitted with a step-up ear. The mechanical power produced is generally used direct y in small workshops, saw-mi s, flourmills, etc. f k Paddle-wheels for boats, although similar in appearance, are excluded (heading 84.87). Hydrometric paddle-wheels are also excluded (heading 90.15). ii PARTS Sub'ect to the general provisions regarding the classification of parts (see the General Exp anatory Note to Section XVI), parts of the hydraulic turbines or water wheels of this heading are also classified here (e.g., rotors, stators, blades and buckets for stators or rotors, casings for spira.1 conduits, regulators which automatically regulate the flow of water or the angle of the variable pitch rotors or stators, according to type, in order to maintain uniformity of the speed of rotation despite variations in the load, valve needles for regulators). t