HOBAS Hydropower Pipe Systems

In the early 1960s, Gommerkraftwerke in the Binn Valley in the Swiss canton of Valais was searching for a suitable material for the pressure pipeline to its hydropower plant. Around the same time, Swiss mechanical engineers were thinking about alternative applications for their textile dyeing rollers. It was a stroke of luck when Gommerkraftwerke heard about the pipes' excellent properties and low weight. The choice of material was clear – and they used the centrifugally cast GRP pipes for the three-kilometer-long, very steep DN 1000 pipeline. Because the material is so light, it did not take them long to install the pipeline with relatively simple equipment. In the steep, rugged terrain of Switzerland's Binn Valley, the HOBAS Pressure Pipeline has proved so reliable that it is still in service today, after more than 50 years.

HOBAS Hydropower Pipelines have a mirror-like inside surface with a small roughness coefficient - they achieve minimal pressure loss and therefore maximal mass flow. Compared to other pipe materials, the higher flow rate at same diameters results in more output. Since the pipes are often laid in mountainous and rough terrain, the durable yet light HOBAS Pipes tip the scales in the decision-making process: their easy handling reduce installation time for more cost savings.

Scope of Supply
Nominal Diameter [DN] 200 - 3600 mm
Nominal Pressure [PN] 1 - 32 bar
Nominal Stiffness [SN] 630 - 1000000 N/m²
Products - Pipes, Joints, Fittings, Accessories
- Angular Cut Systems

HOBAS Sand Trap

A key component for removing solids in small hydro-power systems is the sand trap. After large stones and woody debris are held back by a screen at the weir, the sand trap separates smaller solids such as gravel, sand, and silt from the river water. It thereby prevents sedimentary deposits from building up in the penstock. This, in turn, extends the hydropower plant’s operating time and maintenance intervals, protects the turbine from excessive wear and increases the facility’s service life.

HOBAS has developed a particularly effective, prefabricated sand trap which is built of glass fiber reinforced pipes. Thanks to the modular System and low weight, the HOBAS Sand Trap is transported to the installation site and integrated into the power plant system very easily. A flushing unit, which can be fully automated on request, reliably cleans the sand trap from separated solids. 

The efficiency of the settling system and flushing function of the HOBAS Sand Trap have been proven and verified by means of a numerical simulation model at the ČVUT Prague (Czech Technical University in Prague) and a hydraulic model at the BOKU Vienna (University of Natural Resources and Life Sciences in Vienna).

Each HOBAS Sand Trap is tailored to the given requirements with regard to numerous factors including the solids’ size and settling times as well as the inlet flow velocity. This guarantees best possible settling and flushing performance and optimized long-term performance of the hydropower plant.