Pneumatic tube

Pneumatic tubes (or capsule pipelines; also known as Pneumatic Tube Transport or PTT) are systems that propel cylindrical containers through networks of tubes by compressed air or by partial vacuum. They are used for transporting solid objects, as opposed to conventional pipelines, which transport fluids. Pneumatic tube networks gained acceptance in the late 19th and early 20th centuries for offices that needed to transport small, urgent packages (such as mail, paperwork, or money) over relatively short distances (within a building, or, at most within a city). Some installations grew to great complexity, but were mostly superseded. In some settings, such as hospitals, they remain widespread and have been further extended and developed in recent decades.

A small number of pneumatic transportation systems were also built for larger cargo, to compete with more standard train and subway systems. However, these never gained popularity.

Pneumatic capsule transportation was invented by William Murdoch. It was considered little more than a novelty until the invention of the capsule in 1836. The Victorians were the first to use capsule pipelines to transmit telegrams, to nearby buildings from telegraph stations.

In 1854, Josiah Latimer Clark was issued a patent "for conveying letters or parcels between places by the pressure of air and vacuum." In 1853, he installed a 220-yard (200 m) pneumatic system between the in Threadneedle Street, London, and the offices of the Electric Telegraph Company in Lothbury. The system is known as 'Pneumatic Dispatch'.

While they are commonly used for small parcels and documents – including as cash carriers at banks or supermarkets – they were originally proposed in the early 19th century for transport of heavy freight. It was once envisaged that networks of these massive tubes might be used to transport people.

The technology is still used on a smaller scale. While its use for communicating information has been superseded, pneumatic tubes are widely used for transporting small objects, or where convenience and speed in a local environment is useful.

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Wikipedia