September 2019

plant powered pneumatic rock drills. It was an innovation that resulted in increased productivity over previous manual drilling methods. Furthermore, it contributed to the safety of the workforce by eliminating hazardous steam- driven tools and drills. By 1891 Europe’s first dedicated compressed air plant in Paris was producing the equivalent of 18,000 kW across the city. Although it never outperformed electricity, the concept did spark interest in compressed air’s potential for production processes. Soon, inventors were moving in to patent a variety of tools that ran on compressed air. It was the development of pneumatic tools, rock drilling equipment and compressors in this era that took the Swedish company, AB Atlas Diesel, founded in 1873, from producing rail rolling stock, boilers, and steam and diesel engines, to becoming a world-leading specialist in compressed air, with an impressive record of notable innovations. 1904 saw its first steam- driven piston air compressor. Fifty years later, the company introduced the first rotary screw compressor, based on an improved version of Alf Lysholm’s helical element concept. A string of technical developments followed from the company, now known as Atlas Copco, including the first oil-free, electrically driven screw compressor in 1967, which opened up new opportunities for pure air for medical care and the food industry. In 1994 Atlas Copco launched the first fully integrated variable-speed drive compressor unit. This new product made possible a whole new standard of energy efficiency in the industrial workplace. Further development saw energy consumption, noise levels and footprint dramatically reduced, and compressors connected via the internet into a factory’s network. This constant drive for innovation has turned compressed air from just an alternative power source into an essential fourth utility, supporting the smart factories of the 21st century and playing a crucial role in the production of just about everything in our homes, workplaces and leisure pursuits. systems, throughout the Western world for almost 200 years. However, working conditions were dangerous, dirty and dark. Coal-fired steam- raising meant workers emerged after long hours coated with soot and suffering from eye problems and lung diseases. The pioneering work of Newcomen and Watt with steam technology in the mid-1700s prepared the way for the development of sophisticated heat engines, innovations that in the early 20th century expedited the large-scale generation of electricity, which ultimately replaced steam. Clean power arrives Ironically, a coal-powered steam engine attached to the world’s first electric generator at Thomas Edison’s plant in New York City provided the first electric light in 1880. Five years later an Italian named Galileo Ferraris produced the first two-phase electric induction motor. However, it was the chief electrician at the AEG company in Berlin who developed the ideas of both Nikola Tesla and Ferraris, with designs for a three-phase cage induction motor, still used today. Shortly afterwards, a British patent was filed by Swedish engineer and inventor Jonas Wenström for the components of a three-phase electrical power system. In 1890 he built a three-phase generator that became the heart of the first AC power transmission system installed in Sweden. Large-scale electrification of factories began around 1900 after the development of the AC motor. At first, large motors were added to workshop line shafts, but as soon as small- horsepower motors became widely available, factories switched to workplace unit drives. Eliminating line shafts freed factories from layout constraints and they became more efficient ? in much the same way as many of today’s workplace stationary air compressors, sited at the point of use rather than in a remote compressor house. Compressed air comes of age With the Industrial Revolution, the mechanical air compressor was born, inspired by John Wilkinson’s hydraulic blowing machine. Far from just heating blacksmiths’ fires, the air compressor was now in use in metal mines, fabrication plants and in underground work areas where ventilation was needed. The idea of using compressed air to transmit energy became popular around 1800 as metal manufacturing plants grew. Unlike steam, compressed air could be piped over long distances without incurring pressure losses due to condensation. An early application was in the drilling of the eight-mile-long Mont Cenis rail tunnel in Switzerland in 1861, where compressed air 28 | Plant & Works Engineering www.pwemag.co.uk September 2019 Process, Controls & Plant Focus on: Compressed Air