Carl Paul Gottfried von Linde (born 11 June 1842 in Berndorf (Oberfranken); died 16 November 1934 in Munich) was a German engineer who developed the basics of modern refrigeration technology. Linde was a member of scientific and engineering associations, including being on the board of trustees of the German National Metrology Institute and the Bavarian Academy of Sciences and Humanities.

Biography

Early years

Born the son of a priest, Linde was expected to follow in his father's footsteps, but took another direction entirely. In 1861, he started a course in engineering at the Swiss Federal Institute of Technology in Zürich, Switzerland, where his teachers included Rudolf Clausius, Gustav Zeuner and Franz Reuleaux.

In 1864 Linde finished university, and Reuleaux found him a position as an apprentice at the Kottern cotton-spinning plant in Berlin. He started there the same year but stayed only a short time before moving to the new Krauss locomotive factory in Munich, where he worked as a construction engineer. Linde married Helen Grimm in February 1866; their marriage lasted 53 years and they had six children.

In 1868 Linde heard about the opening of a new university in Munich (the Technische Hochschule) and immediately applied for a job as a lecturer; when he was accepted for the position he was only 26 years old. Linde set up an engineering lab, where students such as Rudolf Diesel studied the subject.

Middle years

In 1871 Linde published an essay on improved refrigeration techniques. This caught the interest of a large number of breweries, and soon Linde was supplying them with his refrigerating machines, while constantly working to improve them.

In 1878 Linde made the decision to put all his time and effort into the production of refrigerating machinery; he gave up his professorship and founded a refrigerating company, Lindes Eismaschinen AG, (now Linde AG ) in Wiesbaden. Business went well; the company sold products to breweries, slaughterhouses and cold storage companies all over Europe.

In 1890, Linde moved back to Munich, where he took up his professorship once more, and developed his new, ground-breaking refrigeration technique, now known as the "Linde technique" (see Inventions). In 1895, Linde files for patent protection of his process for liquefaction of atmospheric air or other gases (approved in 1903). In 1901, Linde began work on a technique to obtain pure oxygen and nitrogen.

Later years and Death

From 1910 Linde withdrew from his position as head of his now hugely successful company, passing on the leadership to his sons Friedrich and Richard. The Great Depression of 1929 was a hard blow to Linde AG, but the company rallied and Linde saw profits start to rise before his death in 1934 at the age of 92.

Inventions

Linde developed the basic techniques of modern refrigeration. In 1871 he invented a system which worked on methyl ether, which was built at Augsburg engineering works. The second generation of refrigerators, from 1876, worked on nitrogen. Both systems used the principle of cooling gas; until then cooling had taken place mechanically. In 1894, following a request from the Guinness brewery in Dublin for a new cooling technique, Linde developed a revolutionary new method (Linde technique) for the liquefaction of large quantities of air.

Linde's method was based on the works of James Prescott Joule and Lord Kelvin, and the introduction of the countercurrent technique. Air is sucked into the machine, where it is compressed, pre-cooled and decompressed; at this point it cools down. In the countercurrent heat exchanger, the air which has already been cooled is used to cool more compressed air, which again cools the next input of air. Continual repetition leads to further lowering of the temperature until the air is liquified. Linde's invention made it possible for physicists to study cryogenics and separate the elements of liquid air by fractional distillation.

Patents

• US727650 -- May 12, 1903 -- Linde oxygen process
• US728173 -- May 12, 1903 -- Equiptment for Linde oxygen process
• US795525 -- July 25, 1905 -- Equiptment for Linde oxygen and nitrogen process

External links

• Linde AG (Homepage)
• Information on Carl von Linde at the Chemical Heritage Foundation
• Linde's air liquefaction machine at the German Museum in Munich [German]

Further reading

• Carl von Linde: "Aus meinem Leben und von meiner Arbeit" (Memoirs: "From my life and about my work"), first published 1916, reprinted by Springer 1984.