Nils Gustaf Dalén’s motto was: Be Optimistic. He demonstrated this motto to himself: when lost his vision in an explosion while working in the factory, he did not give up, and continued to work until his last breath.

Nils Gustaf Dalén or Gustaf Dalén (1869-1937) could have completed his life as a farmer by farming on the land of his parents but he used his inquisitive gifts. He went onto become became an engineer, inventor, Nobel Laureate, industrial leader, and long-term CEO of the AGA company.

Gustaf Dalén was born in Stenstorp in the Västergötland province of Sweden. He initially worked on the family and increased the yield on the land, and also started trade in seeds and ran a small dairy. In 1892 he invented a milk-fat tester that checked the milk quality. He journeyed to Stockholm to show his milk-fat tester to Gustaf de Laval who was impressed by the self-taught Dalén for daring to test the ‘impossible ideas’; and he suggested young Dalén to obtain technical education. Dalén heeded his advice, and went on to obtain formal education at Chalmers University of Technology in Gothenburg and ETH in Zurich. He earned his Master’s degree and a doctorate from Chalmers in 1896.

After completing his formal education, Gustaf Dalén went to work in the industry of acetylene appliances and at the Da Laval’s Steam Turbine Company.  In 1906 Dalén became chief engineer at the Gas Accumulator Company (manufacturer and distributor of acetylene) or Svenska Aktiebolaget Gasaccumulator (AGA). In 1909 he was appointed as the Managing Director of the same company renamed as AGA. It was at AGA where he invented most of his inventions and got patents. Under his leadership at AGA, where he was hired as the chief engineer and workshop manager and subsequently became the company’s CEO. He made the company a global enterprise. Though the company was hit by strikes and by economic recession, in 1912 a large order came from the Panama Canal in Central America by which time he had invented Dalén’s light for lighthouses. AGA developed lighthouses using Dalén’s products.

The Dalén’s light was used in lighthouses and buoys which was an ‘automatic regulator used in conjunction with gas accumulators for illuminating lighthouses and buoys’.

In total, AGA was granted 250 patents under Gustaf Dalen’s life. One of his last great inventions was the legendary AGA stove which was launched in 1929. As the inventor, he inferred that the products ‘should have a solid market place’ before introduced into the market.


Dalén initially worked with acetylene (ethyne) which is flammable and sometimes an explosive hydrocarbon gas. He also invented Agamassan (Aga) which is substrate that absorbs the gas allowing safe storage, and this is commercially used.

ACETYLENE: Acetylene is a colourless gas that burns with a bright flame used in cutting and welding metal. It is the simplest and best-known member of the hydrocarbon series. It is a colourless, inflammable gas widely used as a fuel in oxyacetylene welding and cutting of metals. Acetylene produced an ultra-bright white light which superseded the less bright LPG as the fuel of choice for lighthouse illumination.

Dalén used the new fuel and developed a light that came to be known as Dalén’s light and this also had another invention called ‘sun valve’ the regulating valve. Sun valve enabled the light ‘to operate only at night’. The valve, based on the difference in expansion between black and white metal rods, could extinguish beacons during daytime. Thus, conserving fuel and reducing gas consumption and prolonged the light to over a year such as in a lighthouse. He was awarded the Nobel Prize in Physics in for his invention of the automatic sun valve (Solventil). The solventil regulated gaslight source by the action of sunlight, turning it off at dawn and on at dusk or at other periods of darkness. It rapidly came into worldwide use for buoys and unmanned lighthouses.


The light in the lighthouses by the coasts or seashores functioned by burning an open flame or mixed with air in an incandescent mantle and acetylene produced a light equal to that of oil. Lighthouses enable navigation for the seafarers. In the nineteenth century acetylene gas began to be used to light their beacons.

BUOY: Buoy is a floating object anchored to the bottom of the sea or river to mark places that are dangerous for boats or to show where boats may go.

The AGA lighthouse equipment worked without any type of electric supply and was thus extremely reliable. Its lighthouse equipment and buoys were used widely in Scandinavia for they were reliable and safe. The AGA Lighthouses lighted up the entire Panama Canal at that time.


Nobel Prize for Physics in 1912 awarded to Gustaf Dalén for inventing automatic regulators for gas accumulators for lighthouses and buoys

Gustaf Dalen passed away quietly on December 9, 1937 with his family in the villa on Lidingö in Sweden.


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