Fire piston
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A fire piston, sometimes called a fire syringe, is a device of ancient origin which is used to kindle fire. It uses the principle of the heating of a gas (in this case air) by its rapid (adiabatic) compression to ignite a piece of tinder, which is then used to set light to kindling. [1]
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[edit] Description and use
A fire piston consists of a hollow cylinder ranged in size from around 3 inches to 6 inches (7.5 cm to 15 cm) long, sealed at one end and open at the other. A piston, about a quarter inch (ca 0.64 cm) in diameter, can slide into the cylinder forming an airtight seal with the cylinder wall. The piston has a handle on the end to allow a firm grip to be applied to it and can be completely withdrawn from the cylinder.
Native, and modern versions, are made from wood, horn, antler and bamboo. Lead was used to cast fire pistons in both modern and native versions. Other metals have also been used in modern versions. The piston has a notch or recess in its face into which a piece of tinder is placed.
The piston must be rammed rapidly into the sealed cylinder with a single stroke. The compression of the air causes the temperature to rise rapidly to 260 degrees Celsius, or 500 degrees Fahrenheit. This is hot enough for the tinder on the piston face to ignite. It can then be withdrawn and transferred to a larger mass of kindling to create a fire.
[edit] History
Fire pistons have been used by native peoples of South East Asia and the Pacific Islands as a means of kindling fire since prehistory. They are found in cultures where the blow pipe is used as a weapon and this suggests they may have developed out of blow pipe construction. Their use has been reported from Burma, the Malay Peninsula, Indo-China, Borneo, Sumatra, Java, Kalimantan, Sulawesi, the Philippines, Madagascar [2] and South India. [3]
An 1876 New York Times article reported the discovery of the earliest date of its use in the west. It reports an address by a Professor Govi that claimed a book written by Father Boscovich, of Rome in 1755, De Litteraria Expeditione per Pontifican Ditionem, (The Clever Mechanism) makes the claim that the fire piston was invented in 1745 by Abbe Augustin Ruffo. This report also claims that the modern fire piston was reinvented independently in the west through experiments with the air gun and not modelled after native designs.
It is recorded that the first fire piston made its wider debut in front of scientists in 1802 and was patented in 1807 simultaneously in both England and France. Fire pistons, or fire syringes as they were called then, were popular household tools throughout Europe during the early nineteenth century until the safety match was invented in 1844.
The fire piston may have inspired Rudolf Diesel in his creation of the diesel engine around 1892.[4]
The device is still crafted and sold in the west by a few individuals who also supply larger survival and bushcraft companies.
[edit] As a scientific curiosity
A fire syringe is a piston-and-cylinder device used to demonstrate compression ignition. A typical fire syringe is a thick-walled transparent cylinder fitted with a metal piston which can travel to within a short distance of the bottom of the cylinder.
Compression ignition is demonstrated by placing a matchhead or other piece of tinder at the bottom of the fire syringe and then plunging the piston forcefully into the cylinder. The tinder then bursts into flame due to the rapid rise in temperature which accompanies the sudden reduction in volume (and increase in pressure) of the air beneath the piston. The energy provided by the arm muscles working to compress the air is transferred into the much reduced volume of the air during compression and manifests itself as heat energy sufficient to ignite the tinder. Compression ignition is the principle underlying the operation of a Diesel engine.
[edit] Why it works
Rapid compression of a gas (known as adiabatic compression) increases its pressure and its temperature at the same time. If this compression is done too slowly the heat will leak away to the surroundings as the gas returns to equilibrium with them. If the compression is done quickly enough then there is no time for equilibrium to be achieved and the absolute temperature of the gas can suddenly become several times that of its surroundings, increasing the original room temperature of the gas to a temperature hot enough to set tinder alight. The air in the cylinder acts both as a source of heat and an oxidizer for the tinder fuel.
The same principle is used in the diesel engine to ignite the fuel in the cylinder rather than the spark plug used in the gasoline engine. It is closer, however, to the hot bulb engine, an early antecedent to the diesel, since the fuel (tinder) is compressed with the gas, while in a diesel it is injected when the gas is already compressed and at the high temperature.
Fire pistons have a compression ratio of about 25 to 1. This compares with about 20:1 for a modern diesel engine and 10:1 for a gasoline engine. The piston of the firepiston is made deliberately narrow so that the force on the piston is not too great to make it impossible for unaided human strength to compress the air in the cylinder to its fullest extent. To achieve the compression ratio, the final compressed volume of the tinder and air must be small relative to that of the length of the piston tube. These two factors together mean that only a tiny amount of tinder can be lit by a fire piston, but this is sufficient to light other tinder, and then to light a larger fire.
Easily combustible materials such as char cloth or amadou work well as tinder in the fire piston. The tinders that work best in the fire piston combust at a very low temperature. Cotton fibers for example combust at 235 °C (455 °F) and will light in fire pistons.
By using the right sort of tinder a pressure of only about 3 pounds-force per square inch (20 kPa) will allow the tool produce a glowing coal.
The physics and heat enthalpy equations of a fire piston are explained at General Problems 7.74
[edit] Notes
- ^ Manansala, Paul K. (March 24, 2006). Metallurgy, Southeast Asian (Glossary) Piston bellows. Retrieved on 2007-05-28.
- ^ OGATA, Masanori; Yorikazu SHIMOTSUMA (October 20-21, 2002). Origin of Diesel Engine is in Fire Piston of Mountainous People Lived in Southeast Asia. First International Cpnference on Business and technology Transfer. Japan Society of Mechanical Engineers. Retrieved on 2007-05-28.
- ^ >Raghavan, M. D. (July, 1935). The Fire-Piston in South India.. Man, Vol. 35 104-106. Royal Anthropological Institute of Great Britain and Ireland. Retrieved on 2007-08-04.
- ^ (1952). Diesel Story [Film]. Prelinger Archives: Shell Oil. Retrieved on 2007-02-16.
[edit] References
- Jamison, The Remarkable Firepiston Woodsmoke (1994) Menasha Ridge Press, Birmingham AL ISBN 0-89732-151-0
- Rowlands, John J. The Cache Lake Country (1947) ; W. W. Norton and Company, Inc., New York, NY
- Balfour, Henry , M.A. The Fire Piston Annual Smithsonian Report (1907)
- Fox, Robert The Fire Piston and Its Origins in Europe Technology and Culture, Vol. 10, No. 3 (Jul., 1969), pp. 355-370
- New York Times Article, 1876; http://query.nytimes.com/mem/archive-free/pdf?_r=3&res=9400E5D61F3FE73BBC4153DFB667838D669FDE&oref=slogin&oref=slogin&oref=slogin
- Arbor Scientific, Tools That Teach, Fire Syringe P1-2020; http://www.arborsci.com/Data_Sheets/P1-2020_DS.pdf
