Various company made these buoys and beacons, the most well known were AGA and Chance Brothers. Other lesser known companies include Pintsch Bamag, Henry Lapaute, Joyce and Brandt.
It was the company’s inventions within lighthouse technology – the flashing beacon in 1905, the AGA compound in 1906, the sun valve and Dalén mixer in 1907 – which were to dictate the company's future.
By 1909 Dalén was president for the company. 1912 Gustaf Dalén was badly injured in an explosion which left him blind for life. He was still convalescing when the Swedish Royal Academy of Sciences awarded him the Nobel Prize in Physics for his “inventions of self-operating regulators, which in combination with gas accumulators can be used to light lighthouses and light buoys." He never regained his sight but he remained as the company's president for another 25 years, until his death 1937.
This turns the beacon on and off using daylight. The first one was erected on Furuholmen’s lighthouse between Stockholm and Vaxholm. The design was so ingenious that many prominent contemporary engineers, including Thomas Alva Edison, doubted that the sun valve could work. The patent office in Berlin went so far as demand a special demonstration before it would approve the patent application.
The AGA Sun Valve
The sun valve consists of a central, blackened, light absorbing metal rod surrounded by three gilt light-reflecting metal rods, all parallel with each other. In darkness all the rods are the same temperature and length. When dawn breaks the blackened rod absorbs light energy and acquires a slightly higher temperature than the shiny rods. The blackened rod becomes very slightly longer than the shiny ones triggering a device which cuts off the gas and switches off the lighthouse light.
When dusk falls, the blackened rod contracts, the gas valve opens and a small pilot flame lights the beacon. Combined with the flashing apparatus, the sun valve saves 94% of the gas compared with having the beacon alight all the time.
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A website containing the collected writings of Dr Ken Trethewey
Author of Lighthouses - Race to Illuminate the World
Information about AGA aids of navigation