As part of the rehabilitation of the Saint-Martory causeway on the Garonne River, IVEA has once again demonstrated the relevance and efficiency of its patented gravity closure system, this time for a bar screen that has to be lowered under its own weight in the event of a power cut. A safety imperative to guarantee the region's drinking water supply...

To meet highly strategic challenges...

Through the Saint-Martory canal, the Saint-Martory causeway meets a number of highly strategic challenges: supplying drinking water to more than 200,000 inhabitants, irrigating more than 10,000 hectares, supplying water for fire-fighting, providing low-water support to tributaries (the Louge and Touch rivers) and supplying hydroelectric power through the operation of 5 waterfalls.

Driven by Network 31 (Syndicat mixte de l'eau et de l'assainissement de la Haute-Garonne), carried out under the project management ofEGISThe rehabilitation work will be completed in 2019:
- on the one hand, to secure the Saint-Martory roadway against geotechnical hazards and river erosion;
- secondly, to restore ecological continuity, with the creation of a downstream arm and fish passage structures.

... A patented, ingenious and specific solution

The planned improvements included the redevelopment of a downstream passage equipped witha bar screen. This invaluable filtering equipment is inclined by 15° by means of hydraulic jacks, which allow the screen plane to be lowered to the bottom of the canal if the upstream water level alert threshold is exceeded.

But when dirt accumulates, electrical failure can occur, locking the device in the raised position, with no way of cutting off the water supply! This is where IVEA has been able to demonstrate its expertise with its patented solution A special device - based on motorized jacks, a reversible servomotor and a braking module - enables the grid to descend by gravity under its own weight, at a speed controlled by a variable speed drive, in the event of a power cut.

An ingenious safety device, particularly welcome in view of the major operating challenges involved. And proof that gravity closure is not just for sluice gates (see our references in Haute-Garonnein Italy...): many other structures and equipment can use this basic principle to prevent or solve safety problems that may arise without electrical power...