 | The first compressor - the lung
Many technical applications originate from the earliest days of mankind. The first use of compressed air was blowing on tinder to fan a flame. The air used for blowing was compressed in the lungs. Indeed, the lung could be called a kind of natural compressor. The capacity and performance of this compressor is extremely impressive. The human lung can process 100 l/min or 6m³ of air per hour. In doing so it generates a pressure of 0,02 - 0,08 bar. In a healthy condition, the reliability of the human compressor is unsurpassed and it costs nothing to service.
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Fig. 1.1: The first compressor - the lung | The further development of the „lung“
However, the lung proved to be wholly inadequate when people began to smelt pure metals such as gold, copper, tin and lead more than 5000 years ago. And when they started to make high grade metals, such as iron from ore, further development of compressed air technology was essential. More powerful aids than the lung were needed to generate temperatures of over 1000°C. At first they used the high winds on uplands and the crests of hills. Later, Egyptian and Sumerian goldsmiths made use of the blast pipe. This brought air directly into the embers, which increased the temperature decisively. Even today, goldsmiths all over the world use a similar device. However, this is only useful for melting small quantities of metal.
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Fig. 1.2: Picture of the foot-powered bellows
in ancient Egypt | The first mechanical compressor - the bellows
The first mechanical compressor, the hand-powered bellows, was developed in the middle of the third millennium BC. The much more powerful foot-powered bellows was invented around 1500 BC. This progress was necessary when the alloying of copper and tin to make bronze developed into a stable manufacturing process. The development can be seen in a wall-painting of an ancient Egyptian grave. It was the birth of compressed air as we know it today. |