A sun valve (Swedish: solventil, "solar valve") is a flow control valve that automatically shuts off gas flow during daylight. It earned its inventor Gustaf Dalén the 1912 Nobel Prize in Physics. Subsequently other variants of sun valve were developed for different uses.
Sun valve designed by Gustaf Dalen, 1912, TM34299 - Tekniska museum - Stockholm
The valve was the key component of the Dalén light used in lighthouses from the 1900s through the 1960s, by which time electric lighting was dominant.
Prominent engineers, such as Thomas Edison, doubted that the device could work. The German patent office required a demonstration before approving the patent application.[1]
Designedit
The valve is controlled by four metal rods enclosed in a glass tube. The central rod that is blackened is surrounded by the three polished rods. As sunlight falls onto all of the rods, the absorbed heat of the sun expands the dark rod, switching a valve to cut the gas supply. After sunset, the central rod cools down, contracting to become the same length as the polished rods and opening the gas supply. The gas is lit by the small, always-burning pilot light.
Reliabilityedit
Dalen's system of acetylene lighting for marine navigation proved very reliable, as exemplified by the lighthouse at Chumbe Island off Zanzibar. This lighthouse was constructed in 1904 and converted to unstaffed automatic acetylene gas operation in 1926.[2] The acetylene lighting installation, controlled by a sun valve, remained in use until the lighthouse was converted to a solar-powered (photovoltaic) system in 2013.[3]
Other variantsedit
In 1921 Francis Everard Lamplough (an engineer with AGA's rival firm in lighthouse provision: Chance Brothers) patented an alternative 'light valve'[4] in the hope of breaking Dalén's effective monopoly. In subsequent years it was installed on several lighthouses and beacons, but because of its dependence on liquid it could only be used in static locations (unlike Dalén's valves, very many of which were installed on floating buoys).[5] Lamplough's 'valve' was a form of rocker switch, on which were mounted two glass bulbs, one black, the other clear, part-filled with liquid ether and linked by a tube. During the day, heat from the sunlight would cause the air in the black bulb to expand, forcing the liquid into the clear bulb, the additional weight tipping the switch and cutting off the current to the lamp; at night, or at other times of insufficient daylight, the process was reversed, reconnecting the current.[6]
^Jeremy D'Entremont (August–September 2004). "Zanzibar's Chumbe Lighthouse Celebrates a Century of Service". Lighthouse Digest. from the original on 2017-09-27.
^. Chumbe Island Coral Park. Archived from the original on 2017-07-18.
valve, valve, swedish, solventil, solar, valve, flow, control, valve, that, automatically, shuts, flow, during, daylight, earned, inventor, gustaf, dalén, 1912, nobel, prize, physics, subsequently, other, variants, valve, were, developed, different, uses, desi. A sun valve Swedish solventil solar valve is a flow control valve that automatically shuts off gas flow during daylight It earned its inventor Gustaf Dalen the 1912 Nobel Prize in Physics Subsequently other variants of sun valve were developed for different uses Sun valve designed by Gustaf Dalen 1912 TM34299 Tekniska museum Stockholm Contents 1 Dalen s valve 1 1 Design 1 2 Reliability 2 Other variants 3 ReferencesDalen s valve editThe valve was the key component of the Dalen light used in lighthouses from the 1900s through the 1960s by which time electric lighting was dominant Prominent engineers such as Thomas Edison doubted that the device could work The German patent office required a demonstration before approving the patent application 1 Design edit The valve is controlled by four metal rods enclosed in a glass tube The central rod that is blackened is surrounded by the three polished rods As sunlight falls onto all of the rods the absorbed heat of the sun expands the dark rod switching a valve to cut the gas supply After sunset the central rod cools down contracting to become the same length as the polished rods and opening the gas supply The gas is lit by the small always burning pilot light Reliability edit Dalen s system of acetylene lighting for marine navigation proved very reliable as exemplified by the lighthouse at Chumbe Island off Zanzibar This lighthouse was constructed in 1904 and converted to unstaffed automatic acetylene gas operation in 1926 2 The acetylene lighting installation controlled by a sun valve remained in use until the lighthouse was converted to a solar powered photovoltaic system in 2013 3 Other variants editIn 1921 Francis Everard Lamplough an engineer with AGA s rival firm in lighthouse provision Chance Brothers patented an alternative light valve 4 in the hope of breaking Dalen s effective monopoly In subsequent years it was installed on several lighthouses and beacons but because of its dependence on liquid it could only be used in static locations unlike Dalen s valves very many of which were installed on floating buoys 5 Lamplough s valve was a form of rocker switch on which were mounted two glass bulbs one black the other clear part filled with liquid ether and linked by a tube During the day heat from the sunlight would cause the air in the black bulb to expand forcing the liquid into the clear bulb the additional weight tipping the switch and cutting off the current to the lamp at night or at other times of insufficient daylight the process was reversed reconnecting the current 6 In 1935 one Edwin H Pendleton was granted a US patent for a sun valve activated by a pair of bimetallic strips 7 References edit The Sun Valve History from the AGA website archived link Jeremy D Entremont August September 2004 Zanzibar s Chumbe Lighthouse Celebrates a Century of Service Lighthouse Digest Archived from the original on 2017 09 27 Historical Monuments Chumbe Island Coral Park Archived from the original on 2017 07 18 Patent listing Chance Toby Williams Peter 2008 Lighthouses the Race to Illuminate the World London New Holland Publishers UK Ltd p 243 Photo Shipping Wonders of the World 3 27 February 1936 Retrieved 21 March 2019 Patent No US1997598 nbsp This physics related article is a stub You can help Wikipedia by expanding it vte Retrieved from https en wikipedia org w index php title Sun valve amp oldid 1180841434, wikipedia, wiki, book, books, library,
