Trompe

A trompe is a water-powered gas compressor, commonly used before the advent of the electric-powered compressor. A trompe is somewhat like an airlift pump working in reverse.

Trompes were used to provide compressed air for Bloomery furnaces in Spain and the USA. [cite book
last = Bond
first = A. Russel
authorlink =
coauthors =
title = The Story of Mechanics
publisher = P. F. Collier & Son Corporation
date = 1939
location = New York
pages = 90–93
url =
doi =
id =
isbn = ] The presence of a trompe is a signiture attribute of a Catalan Forge, a type of Bloomery Furnace.

In Paris they were used for a time to compress air to drive the city's first electricity generation scheme, and in the Alps they were used in France and Switzerland to provide compressed air for early alpine tunnels. [cite book
last = Bell
first = Louis
authorlink =
coauthors =
title = Electric Power Transmission: A Practical Treatise for Practical Men
publisher = Electrical World and Engineer
date = 1901
location = New York
pages =
url =
doi =
id =
isbn = ]

Trompes can be enormous. At Ragged Chute in Canada water falls down a shaft 351 feet (105 metres) deep and nine feet (2.7 m) across to generate compressed air for mining equipment and ventilation. [http://www.cobalt.ca/ragged_chutes.htm Ragged Chutes ] ]

Operation

Trompes are very simple devices that consist of a vertical pipe or shaft going down to a separation chamber, a pipe coming away from that chamber to allow the water to exit at a lower level, and another pipe coming from the chamber to allow the compressed air to exit as needed.

Typically water rushing down the vertical pipe falls through a constriction where an external port allows air to be sucked in because of the lower pressure of a venturi effect. As the air goes down the pipe it is pressurized proportional to the hydraulic head. The now compressed air rises to the top of the separation chamber for use as a power source. The energy of the falling water entrains the air into the water, but is not the energy that pressurizes the air as is often incorrectly sighted. That is solely a derivative of the hydraulic head.

Large trompes were often situated at high waterfalls so that plenty of power was available.The Ragged Chute plant on the Montreal River near the town of Cobalt, Ontario, is a trompe and tourist attraction. It is now owned by Canadian Hydro and exists beside a modern hydroelectric plant.

References

External links

* [http://www.motherearthnews.com/Alternative_Energy/1977_July_August/Harness_Hydro_Power_with_a_Trompe An article on trompes] in Mother Earth News (retrieved November 26 2006)
* [http://www.cobalt.ca/ragged_chutes.htm The Ragged Chutes machine] in Cobalt Ontario. Uses a 17-meter head. (retrieved April 21 2007)
* [http://www.waymarking.com/waymarks/WM447R Trompe Catalan Furnace] in San Juan Capistrano, California
* [http://www.cat-science.com/admin/articles/pdf_990102/7_The_Catalan.pdf The Catalan process for the direct production of malleable iron and its spread to Europe and the Americas PDF]