Introduction of Pelton turbine
The Pelton type turbine is usually the preferred turbine for hydropower, when the available water source has relatively high hydraulic head at low flow rates, where the Pelton wheel is most efficient. They have the advantages such as compact structure, small size, high efficiency, low operation maintenance cost, low cost because of less excavation and less investments, etc. and disadvantages like inadequate energy recovery and lower efficiency than other types of turbines.
Application scope of head: 80m~1200m
Runner diameter: 0.6 m ~ 3.5m
Installable capacity: 200KW ~ 80000KW
Theirs shaft arrangements are either vertical or horizontal and they may have single nozzle, twin or multi-nozzles. With characteristics such as high head, big capacity, multi-nozzle and good structure, etc..
Reference pictures of Pelton turbine
Composition of Pelton turbine
Nozzle, runner, support parts and deflector parts.
Major components: rotating parts(runner, main shaft etc), nozzle parts(nozzle and related control), seat parts(seat, cover, spiral casing etc), pipeline parts(distributing pipe, brake piping, expansion joint etc), bearing parts and others. Core part is the runner and nozzle for structure.
Structure of Pelton turbine
Runner, spray pipe, baffle plate, runner, spiral casing, tail water tank.
1. In order to improve the speed and flow, two or more nozzles are regularly installed on one runner. Sometimes the two (or more) runners are installed on in one main shaft to improve the single output of the unit.
Component: turbine disc, bucket(uniformly distributed along turbine disc).
Connection type: bolt, integrally cast, weld.
Component: nozzle, nozzle body, needle valve, spray beam, operating mechanism.
Needle valve: control the water flow of turbine showed as stroke.
Slowly close the needle valve and reduce the water hammer pressure to deviated water flow out from water scoop and avoid the speed increase.
Guide the water drainage from the scoop into the tail water tank. Generally the spiral casing is steel casting.
Water diversion plate
Prevent the water flow to splash into the above along the runner that cause additional losses.
2. Large and medium-sized Pelton turbine usually use vertical layout, which can reduce the area of power house and is also convenient to installed multi-nozzle.
3. Small and medium-sized Pelton turbine usually adopts horizontal arrangement, which can simplify the structure, lower cost with convenient installation and maintenance.