Power Solutions
Cross-flow Turbines
Turbine
Cross-Flow
JLA Banki / Cross-flow turbines are designed to operate over a wide range of flow rates while guaranteeing a minimum efficiency of 75% to 80%.
In addition to their low runaway speed and robustness, one of the major advantages of this turbine is the relative simplicity of its construction, as there are only two or three moving parts.
Head
2,5 to 80 m
Flow
50 to 1600 l/s
Mechanical power
5 to 400 kW
Rotation speed
100 to 1200 rpm
Water inlet
Horizontal or vertical
The concept of the Banki / Cross-flow turbine was invented in 1903 by Australian engineer Michell.
It is a machine characterized by its relative simplicity and great robustness.
Its uniqueness lies in the double effect exerted by the water flow on the runner. Water is directed via a penstcok to the radial injection into the cylindrical runner with a horizontal axis. It is then discharged either at atmospheric pressure or through a partially submerged draft tube, creating a slight vacuum in the turbine, which results in increased power output.
The runner consists of around thirty curved blades, fixed and parallel to the axis of rotation. The water passes through the peripheral blades twice, driving them by a successive centripetal and centrifugal radial flow. This feature also makes the runner completely insensitive to leaves, twigs, algae, plastic packaging, etc., which are ejected after half a turn due to the combined effect of water flow and centrifugal force.
All turbine components are easily accessible, making disassembly of each part straightforward.
Maintenance is limited to periodic lubrication of the bearings. The runner’s condition can be easily checked by removing the front cover.
A Cross-flow turbine admission can have one or two compartments. The compartmentalization of the inlet valve system ensures the turbine’s efficiency when used under low flows. JLA Cross-flow turbines are designed to operate over a wide range of flow rates while guaranteeing a minimum efficiency of 75% to 80%.
Depending on the site’s layout, turbine water inlet can be either vertical or horizontal. JLA Cross-flow turbines are designed to be installed above the tailrace channel, at the lowest level, but out of reach of floods.
In addition to its low runaway speed, one of the major advantages of this turbine is the relative simplicity of its construction, as there are only two or three moving parts:
– The runner
– The flow control elements (valves), of which there may be 1 or 2.
Advantages :
-
Robust and reliable mechanical design -
Simplicity and low maintenance cost -
Efficient management of low and variable flow rates -
Guaranteed minimum efficiency over a wide range of flow rates -
Compact turbine, limited civil engineering work -
Insensitive to leaves, plastics, algae, etc. -
Simple and quick installation from heads of 2.5 m - Low runaway speed
