Hongrin Dam

Project :

Hydro-Exploitation has successfully completed the “bottom valves” project of the Hongrin dam thanks to an optimal sealing of the shutters.

Context :
Some components integrated into the dams require regular maintenance, such as in the case of bottom valves, which can be used for rapidly emptying reservoir lakes and guaranteeing the safety of the population.

Hydro Exploitation employs PXL SEALS to ensure that the shutters placed on the bottom valves are perfectly sealed.

Due to the fact that the structure does not allow the lake to be completely drained, the only solution was to dive in order to fit a shutter on the bottom valve in order to isolate the water section and the section to be renovated downstream of the dam.

This exceptional and spectacular operation represents a first in Switzerland and requires very technical know-how from the companies involved and a flawless coordination for completing this project.
Issues :
- Significance of the maintenance work to ensure round-the-clock operation, providing peak energy at the right time and balancing networks

- Life of the divers and people working downstream of the dam conditioned by the technical reliability of the facilities: no error is allowed.


The PXL SEALS Solution :
The chosen profile was a D profile with a hollow interior section.

The shutters, surrounded by the PXL SEALS seals, were then descended along the dam and immersed at -40 m without touching the wall.

Advantages :

Thanks to its knowledge of elastomeric characteristics and digital simulation, PXL SEALS was able to check the behaviour of the seals and thus control their compression and ensure effective sealing.

About the hydro-electric Hongrin-Leman facility :

Situated in the Waldensian Prealps in Switzerland and built in the late 1960s, the facility was commissioned in 1971 and was one of the first in Europe to be designed for water turbining and pumping.

The Hongrin dam is located in the Waldensian canton, a few kilometres from the Col des Mosses.

About the project :

- 10 years of reflection about the project
- 3 years of intense preparation
- Logistical and technical marathon

Valves manufactured by Adams.

Changing 2 valves after installing the shields. Paint and grid maintenance.

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Application :
Very large diameter sealing system

Project duration : February 2012 (from January to April 2012)

Constraints :

  • Outside temperature of -26°C
  • Multiple service providers and accurate deadlines
  • Shutters installed at 40 m under the surface of the Hongrin lake
  • The precious seals must be in a perfect condition and not be in contact with the walls

Company :
Forces Motrices Hongrin-Léman SA (FMHL)
Société anonyme de partenaires (public limited company of partners)

  • Romande Energie 41.13%,
  • Alpiq 39,31%,
  • Groupe E 13,13%,
  • Lausanne Commune 6,43%.


Creation: 1963

Project designer: Hydro exploitation SA

Description of the company:
Les Forces Motrices Hongrin-Léman S.A. (Public limited company Hongrin-Leman of Driving Forces) form a “société anonyme de partenaires” (public limited company of partners). The company was founded in 1963 in order to develop a hydroelectric facility combining an accumulation system and a pumping-turbining system. These systems are currently operated, under a mandate, by Hydro Exploitation SA in relation to the hydraulic operation group of Chablais.