Gustaf Dalén AGA Lighthouse

This lighthouse was placed here as an honour to the inventor Gustav Dahlén and all the workers at AB Gasaccumulator (now called AGA AB).

This specific lighthouse is an original Model 1927 from Furusund (in the Stockholm archipelago where all the Finland boats are passing on their way to Åland and Helsinki).

AGA started their industrial production in Järla in 1904. The company got renowned mainly for the well-constructed and well-working gas-powered light ouse. With Gustav Dahlén’s invention of the “cliplight,” the beacon could shine short pulses of light, which made them more energy-efficient, as did the sunvalve, which shut off the light during daytime. This resulted in a savings of 94% of the gas that fueled these lights.

The solvent valve contains three shiny metal rods and one matte blackened rod. Since a black surface absorbs heat better than a light one, the blackened rod becomes warmer under daylight. As the blackened rod heats up, it expands, becoming longer, and reaches a valve arm that seals a gas nozzle. When it gets darker, the blackened rod shrinks slightly, and the valve arm opens the gas nozzle again.

The gas-powered main light is reignited by a smaller eternal flame and is thus only turned on when it is needed the most. The solvent valve rendered many lighthouse keepers unemployed, saved a lot of gas, and the invention spread worldwide. In 1912, Blockhusuddens lighthouse in the harbor entrance to Stockholm was the first in the world to have a solvent valve. When it was electrified in 1980, it was found that the valve had never required repair.

This lighthouse cast red and green light out towards the Järla Sjö and a small ray of green up towards the old factory of AGA.

Gustav Dahlén was awarded the Nobel Prize in Physics in 1912.