The bulb hydro turbine is a reaction turbine of horizontal Kaplan type which is used for extremely low heads from 2m to 20m.
The feature of bulb hydro turbine is that the upstream have a watertight casing which contains a generator located on a horizontal axis, the case shape is like a bulb, so it is called bulb hydro turbine.
The bulb tubular water turbine unit is mainly composed of buried parts, generators, water guides, main shafts, bearings, runners, and concrete components. All working parts are on the same axis, which is a horizontal-shaft turbine.
The main difference from the Kaplan turbine is that the water flows in a mixed axial-radial direction into the guide vane cascade and not through a scroll casing. The guide vane spindles are normally inclined to 600 in relation to the turbine shaft and thus results in a conical guide vane cascade contrary to other types of turbines. The runner of a bulb turbine may have different numbers of blades depending on the head and water flow. The bulb turbines have higher full-load efficiency and higher flow capacity as compared to Kaplan turbine.
The Bulb Tubular turbine is the best selection for exploitation of tidal power and hydraulic power with extremely low water head and extremely large discharge. It has large discharge, high specific speed and high efficiency, and needs less excavation in civil works.
- Working on extremely low water head 2m-20m, efficient use the water energy on more great river
- best selection for exploitation of tidal power
- high specific speed and high efficiency, and needs less excavation in civil works, relatively lower construction cost
the bulb turbine have a complicated structure, so the turbine generator are more expensive, sometimes more economical to use a pit turbine/generator, a step-up gearbox increases the speed of the generator to make this component more compact and, therefore, less expensive. This increases the feasibility of these projects. we have extensive experience in bulb/pit turbine technology.
Reference drawing of Bulb hydro turbine: