Air compressors are used in a variety of industries to provide compressed and pressurized air for many applications. These devices are now even used to power construction and manufacturing equipment and to drive control system valves; earlier compressors were much less versatile. The advent of air compressors dates back thousands of years. The earliest air compressor was actually the human lung. Since the human body can exhale oxygen, people once used their breath to stoke fires. The trend of providing our own air pressure faded around 3000 B.C. as the practice of metallurgy became prevalent. Metalsmiths were melting down various materials such as gold and copper, and they soon realized that higher temperatures were needed. Healthy lungs can only produce .02 to .08 bar (1 bar equates to 14.5 psi) of air pressure—hardly adequate for metalworking tasks. Also, the carbon dioxide content in human breath wasn’t helpful for sustaining fires. The demand for stronger air compressors began to grow as time progressed. In 1500 B.C., a new type of air compressor was invented, called bellows. This device was a hand-held (and later foot-controlled) flexible bag that produced a concentrated blast of air ideal for achieving higher temperature fires. Years later in 1762, professional engineer John Smeaton designed a water wheel-driven blowing cylinder that slowly replaced the bellows. Though Smeaton’s device was efficient, it was replaced in turn by the blasting machine invented by John Wilkinson in 1776; Wilkinson’s blasting machine became the archetype for later mechanical air compressors. industrial_air_compressors Air compressors were used for more than just metalworking in those days; they were also used for mining and fabricating metals and providing ventilation to underground areas. During the 1857 construction of the Italy-France rail system, compressors were often used to move large air volumes into the 8-mile construction tunnel. Soon after, people conceptualized more ways to utilize the technology. By 1800, people began using air compressors to transmit energy. Austrian engineer Viktor Popp created the first compressor plant in Paris in 1888; in just three years, Popp’s 1,500 kW compressor plant grew to 18,000 kW. More innovations in air compression kept improving upon the process, and soon began incorporating electricity and pneumatic energy.