DynaVec AS offers innovative solutions for Francis turbines exposed to water with high sediment content. All areas with high water speeds are fully protected with hard-coating (HVOF - Wolfram Carbide). This includes the guide vanes, wear plates towards the upper and lower cover, and the patented runner described below.
DynaVec AS designs and delivers innovative solutions with exchangeable vanes allowing for fully hard-coated runners (HVOF), even for small-sized runners.
The runner vanes are machined with flanges both towards the crown and band side. The crown and band have a set of grooves for the runner vanes, which have flanges that fit into the grooves.
The bolted runner from DynaVec can easily be assembled and disassembled by standard hand tools. This can be performed on-site if a lifting arrangement is present.
Partly assembled Bolted DynaVec runner
Fully assembled Bolted DynaVec runner
As the runner can be separated, all wetted surfaces can easily be HVOF coated. The thermal spray coating (HVOF - High Velocity OXY-Fuel) is applied with robots. Typical coating thickness will be between 0.2 – 0.3 mm.
There are two types of maintenance for the bolted runner. The most efficient is preventive maintenance, where sandblasting and recoating are performed before the coating surface is broken. The alternative is to reshape the geometry if it is damaged before coating, as normally in a planned maintenance schedule. Since the bolted runner can easily be disassembled, this simplifies maintenance and repair compared to a welded runner.