Georges Claude

French chemist and inventor

• Born: September 24, 1870
• Birthplace: Paris, France
• Died: May 23, 1960
• Place of death: St. Cloud, France

Claude was the first successfully to liquefy air in quantity independent of Carl von Linde in 1902. A few years later, Claude’s Liquid Air Company was separating the components of liquid air and producing high-quality oxygen. Founder of Claude Neon, he held a monopoly on the neon-tube industry in the 1920’s.

Early Life

Georges Claude (jawrzh clohd) was the son of a modest family in Paris, France. His father was the assistant director of the Manufactures des Glaces de Saint-Gobin. Claude’s education came principally from a municipal school of physics and chemistry. He was graduated in 1889 and took his first job at the Usines Municipales d’Électricité des Halles. In 1893, he married and later had three children.

As the result of an almost-fatal accident with a high-tension wire, Claude developed safety procedures that he presented to the French biophysicist Arsène d’Arsonval, his teacher and collaborator. Ironically, this would set the stage for some related inventions and a closer relationship with d’Arsonval.

During the years from 1896 to 1902, Claude worked for the Compagnie Française Houston-Thomson. In 1897, Claude discovered that acetylene gas could be handled and transported safely by dissolving it in acetone. His method was largely accepted and resulted in an expansion of the acetylene industry. This was the first of Claude’s discoveries that would trigger the growth of new industrial technology.

In 1902, Claude and d’Arsonval worked on the industrial methods for the liquefaction of gases; in 1903, Claude wrote his first book, L’Air liquide (1903; Liquid Air, Oxygen, Nitrogen , 1913), and he asked d’Arsonval to write the preface. In 1908, d’Arsonval established an international society for cryogenic studies.

It was his work on the liquefaction of air and the subsequent separation of the gases of air that made Claude an industrial giant. Originally, Claude was after inexpensive, high-quality oxygen, which was in demand by hospitals and for oxyacetylene welding. After successfully separating oxygen from liquid air, he also proposed the use of liquid oxygen in iron smelting as early as 1910; his innovations in this process, however, would not be adopted until after World War II. During World War II, he used liquid oxygen in explosives and also produced liquid chlorine for poison-gas attacks. Faced with substantial leftover quantities of the rare gases neon and argon, Claude cleverly built an entirely new technology that resulted in an industrial monopoly.

Life’s Work

On December 24, 1877, Louis Cailletet had liquefied a few drops of oxygen before the Academy of Sciences in Paris. The skeptics of the time asked, “What purpose can the liquefaction of air serve?” Claude, unswayed by negative opinion, envisioned the continuous commercial production of liquid gases and the impact it would have on the metallurgy, chemical, and agriculture industries. Several attempts at large-scale liquefaction had not been entirely successful; Claude would be the first to succeed.

Theory provided Claude with two processes that would cool air sufficiently to liquefy it. The first process is based on the Joule-Thomson effect. The gas was expanded after compression so that work is done against internal forces. The second process is to expand the gas so that it does work against the external forces of an engine. Both processes are based on the principle that a gas cools when it expands. After the gas is allowed to expand, part of the cooler gas is compressed, and the remaining gas is used to carry the heat of compression away. The compressed gas is allowed to expand again. The cycle is repeated until the remaining gas becomes cold enough to form a liquid. In addition, the two processes require that the cooling effect be cumulative, so heat exchangers need to be incorporated in both systems. All the industrial air liquefaction is based on one of these two processes or a combination of them.

The first attempt to liquefy air with an expansion machine was made by Ernest Solvay. In 1887, a patent was granted to him that described three processes for the liquefaction of air. Only one of those processes was tried and resulted in little success. The Joule-Thomson effect was used for large-scale production of liquid air in 1895 by Carl von Linde in Germany and William Hampson in England. In 1902, subsequent work on adiabatic expansion of the gas in a cylinder, with the performance of external work, resulted in the liquefaction of air by Claude in France. This method is thermodynamically more efficient than the Joule-Thomson method, but there were two formidable technical problems for Claude to solve.

The first was that the expansion engine had to be well insulated, since its operating temperature was well below -150 degrees Celsius. In Claude’s successful attempt to liquefy air, he introduced the principle of regenerative cooling. The air that had been cooled by expansion in the cylinder was used to precool the compressed air before it entered the cylinder. As the initial temperature nears the liquefaction point, however, the amount of cooling through expansion at a given pressure decreases. Also, liquid air in the cylinder causes “water-hammer” effects that could fracture the cylinder. The Claude cycle demanded that an optimal pressure and temperature be found for the gas entering the cylinder.

The second problem, since oil freezes at these low temperatures, was to find a method of lubricating the moving parts. Claude’s first solution was to use petrol ether, which remains a liquid down to -140 degrees Celsius, but he achieved better results using pretreated leather in place of the metallic piston rings in the cylinder. This arrangement allowed a small amount of air to leak out between the piston and the cylinder wall; thus, the air is the real lubricant.

The ultimate goal was not simply the liquefaction of air but also the separation of air into its component parts. Linde was the first to achieve this goal with his introduction of a rectification column in 1903 that was capable of separating oxygen from liquefied air. Claude was to achieve the same result, but instead of separating totally liquefied air, he used a process called backward return. This process liquefies only a relatively small portion of the air to be treated to obtain without evaporation a highly oxygenated liquid. The Claude patented processes were put into practice by the Liquid Air Company in France. Over time, several modifications and improvements were added to the Claude cycle.

Claude also developed a process for the manufacture of ammonia in 1917 that was similar to the Fritz Haber process. Claude increased the production of ammonia by using a high operating pressure. Also, by transferring the heat of reaction to the incoming hydrogen and nitrogen mixture, he could more efficiently bring them to the reaction temperature.

Claude’s success in separating the components of air left him with considerable quantities of rare gases. Searching for a way to use the leftover gases, Claude would start a million-dollar industry. In 1897, Sir William Ramsay discovered that when neon, a chemically inert and colorless gas, is placed in evacuated tubes and an electric current is passed through the tubes, the neon gas glows reddish-orange. Yet the cost of isolating the rare gases at that time was too expensive for a commercial product. The relatively cheap large-scale isolation of the components of air by both Linde and Claude in 1907 made possible a commercial product.

In 1910, Claude displayed his first neon sign at the Grand Palais in Paris. Neon-filled tubes produced a reddish-orange, and argon produced a grayish-blue. By coating the inside of the tubes, Claude found that he could expand his range of colors. Unfortunately, the first neon tubes had short lifetimes because of the corrosion of the electrodes. In 1915, Claude received a patent for an electrode that had high resistance to corrosion. Good neon tubes could now last up to thirty years.

The Claude Neon Company grew as a result of his patent, and Claude built a near monopoly in the neon-tube industry. The company’s largest growth occurred during 1925-1929, reaching its peak after World War II. Expansion was inevitable, and Claude Neon became an international organization through an early form of franchising. In 1923, a United States Claude Neon franchise was bought for around 100,000 dollars plus royalties. During the Depression years, Claude neon lights could claim nine million dollars of an eleven-million-dollar industry. Claude Neon would survive the Depression, but when his patent expired in 1932 the competition flourished. Claude Neon would no longer have the monopoly on neon tubes.

A very rich man, Claude turned his attention to still another project in 1933. Claude believed that the generation of energy could be accomplished by transferring the heat of the warm surface water of the ocean to the lower temperature of the depths. Unfortunately, after eight years of effort the project ended in a costly failure.

Claude received many honors in his lifetime. Most important were the John Scott Medal of the Franklin Institute in 1903 and his membership in the Legion of Honor. Claude was also involved in politics, and he joined the Action Française in 1919. He ran, unsuccessfully, for public office in 1928. In the years from 1940 to 1945, he conducted “Conférences sous l’occupation allemande: Mes imprudences et mes malheurs,” and after the war he was accused of being a supporter of the Vichy government. He pleaded guilty; his name was removed from the Legion of Honor; and, despite his age, he spent four and a half years in prison. Several of his friends arranged for his release, but he remained under police surveillance. He wrote many articles, patents, and books. Among his autobiographical books are Souvenirs et enseignements d’une campagne électorale (1932) and Ma Vie et mes inventions (1957).

Significance

In 1903, Claude and Linde began a scientific revolution. Air could be inexpensively liquefied and separated into its components. Cryogenic (low-temperature) studies could flourish, and the world would soon be able to reach extremely low temperatures with ease. The practical liquefaction of air was more than a scientific revolution; it was an industrial, social, and economic revolution as well.

Pure nitrogen, either as a liquid or as a gas, is essential in the following endeavors: ammonia and fertilizer production, blanketing atmospheres for chemical processing, enhanced oil recovery, flash-freezing, electronic manufacture, and aerospace. Claude’s main goal was the inexpensive production of oxygen. His success has changed the standard of living in the modern world. Oxygen is a very chemically reactive element. Pure oxygen, rather than air, can increase production and rates of reactions. There are at least twenty elements essential to life, and it would be hard to name the most essential element of life. Yet oxygen certainly would be on any list. Many people owe their lives to a tank of pure oxygen. The basics of the Claude process are used to separate life-giving oxygen from the air. Life support, be it medical, underwater, or space-related, is possible because of the pioneering work of Claude.

Claude not only enhanced the quality of modern life but also discovered a new form of art. Neon lighting has sold products and added color and excitement to the nightlife of the world’s major cities.

Bibliography

Claude, Georges. Liquid Air, Oxygen, Nitrogen. Translated by Henry E. P. Cottrell. London: J. and A. Churchill, 1913. Claude’s first book. Describes the early work on air liquefaction, including the theoretical aspects. Gives readers a good sense of Claude’s struggle to achieve air liquefaction.

Hoare, F. E., L. C. Jackson, and N. Kurti, eds. Experimental Cryophysics. London: Butterworth, 1961. An excellent account of the development of low-temperature research and the historical development of commercial liquid-air production.

Mendelssohn, Kurt. The Quest for Absolute Zero: The Meaning of Low Temperature Physics. New York: McGraw-Hill, 1966. Mendelssohn concisely describes the development of both processes for air liquefaction and Claude’s role in the development of the external work method of gas liquefaction.

Stern, Rudi. The New “Let There Be Neon.” Rev. ed. New York: Harry N. Abrams, 1988. Stern gives one of the best historical accounts of the development of neon lights. Stern includes photographs of Claude in his laboratory as well as a copy of a front page of Claude Neon News from 1928.

Webb, Michael. The Magic of Neon. Salt Lake City, Utah: Gibbs M. Smith, 1986. Webb briefly describes the history of neon tubes and gives a clear and concise description of how neon tubes are constructed.

Wilcox, Lauren. “The Best and the Brightest.” Smithsonian, March, 2006, 26-28. This article about the Neon Museum in Las Vegas, Nevada, includes information about Claude’s invention of neon lighting.