Fire piston
Encyclopedia
Adiabatic process
In thermodynamics, an adiabatic process or an isocaloric process is a thermodynamic process in which the net heat transfer to or from the working fluid is zero. Such a process can occur if the container of the system has thermally-insulated walls or the process happens in an extremely short time,...
) compression to ignite a piece of tinder
Tinder
Tinder is easily combustible material used to ignite fires by rudimentary methods. A small fire consisting of tinder is then used to ignite kindling. Anything that can be ignited by a match can be considered tinder; or by more rigorous definition, anything that begins to glow under a shower of...
, which is then used to set light to kindling.
Description and use
A fire piston consists of a hollow cylinderPneumatic cylinder
Pneumatic cylinders are mechanical devices which utilize the power of compressed gas to produce a force in a reciprocating linear motion....
ranging in length from about 7.5 cm to 15 cm (3 to 6 inches), having a bore 6-7 mm (about 0.25 inch) in diameter, sealed at one end and open at the other. A piston
Piston
A piston is a component of reciprocating engines, reciprocating pumps, gas compressors and pneumatic cylinders, among other similar mechanisms. It is the moving component that is contained by a cylinder and is made gas-tight by piston rings. In an engine, its purpose is to transfer force from...
with an airtight circular seal
Seal (mechanical)
A mechanical seal is a device which helps join systems or mechanisms together by preventing leakage , containing pressure, or excluding contamination...
is fitted into the cylinder. The piston has a handle on the end to allow a firm grip to be applied to it, or a large enough surface area to strike it sharply without causing pain while the cylinder is braced against a hard surface, and it can be completely withdrawn from the cylinder. The piston generally has a notch or recess on or in its face, into which a piece of tinder
Tinder
Tinder is easily combustible material used to ignite fires by rudimentary methods. A small fire consisting of tinder is then used to ignite kindling. Anything that can be ignited by a match can be considered tinder; or by more rigorous definition, anything that begins to glow under a shower of...
is placed.
The compression of the air when the piston is quickly rammed into the cylinder causes the interior temperature to rise sharply to 260°C (500°F) . This is hot enough for the tinder on or in the piston face to ignite with a visible flash that can be seen if the cylinder is made of translucent or transparent material. The piston is then quickly withdrawn, before the now-burning tinder depletes the available oxygen inside the cylinder. The smoldering tinder can then be removed from the face of the piston and transferred to a larger nest of fine kindling
Kindling
Kindling is a term to describe small pieces of wood and twigs used to start a fire.Kindling may also refer to:* Kindling, a 1915 film directed by Cecil B...
material, such as hemp rope fibres, birch shavings, etc. The ember is then fanned or blown upon vigorously to create a flame, at which time various stages of larger kindling can be added until built into a proper fire.
Ancient and modern versions of fire pistons have been made from wood
Wood
Wood is a hard, fibrous tissue found in many trees. It has been used for hundreds of thousands of years for both fuel and as a construction material. It is an organic material, a natural composite of cellulose fibers embedded in a matrix of lignin which resists compression...
, animal horns, antler
Antler
Antlers are the usually large, branching bony appendages on the heads of most deer species.-Etymology:Antler originally meant the lowest tine, the "brow tine"...
s, bamboo
Bamboo
Bamboo is a group of perennial evergreens in the true grass family Poaceae, subfamily Bambusoideae, tribe Bambuseae. Giant bamboos are the largest members of the grass family....
, or lead
Lead
Lead is a main-group element in the carbon group with the symbol Pb and atomic number 82. Lead is a soft, malleable poor metal. It is also counted as one of the heavy metals. Metallic lead has a bluish-white color after being freshly cut, but it soon tarnishes to a dull grayish color when exposed...
. Other metal
Metal
A metal , is an element, compound, or alloy that is a good conductor of both electricity and heat. Metals are usually malleable and shiny, that is they reflect most of incident light...
s have also been used in modern versions.
History
Fire pistons have been used in South East Asia and the Pacific IslandsPacific Islands
The Pacific Islands comprise 20,000 to 30,000 islands in the Pacific Ocean. The islands are also sometimes collectively called Oceania, although Oceania is sometimes defined as also including Australasia and the Malay Archipelago....
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
Borneo
Borneo is the third largest island in the world and is located north of Java Island, Indonesia, at the geographic centre of Maritime Southeast Asia....
, Sumatra
Sumatra
Sumatra is an island in western Indonesia, westernmost of the Sunda Islands. It is the largest island entirely in Indonesia , and the sixth largest island in the world at 473,481 km2 with a population of 50,365,538...
, Java
Java
Java is an island of Indonesia. With a population of 135 million , it is the world's most populous island, and one of the most densely populated regions in the world. It is home to 60% of Indonesia's population. The Indonesian capital city, Jakarta, is in west Java...
, Kalimantan
Kalimantan
In English, the term Kalimantan refers to the Indonesian portion of the island of Borneo, while in Indonesian, the term "Kalimantan" refers to the whole island of Borneo....
, Sulawesi
Sulawesi
Sulawesi is one of the four larger Sunda Islands of Indonesia and is situated between Borneo and the Maluku Islands. In Indonesia, only Sumatra, Borneo, and Papua are larger in territory, and only Java and Sumatra have larger Indonesian populations.- Etymology :The Portuguese were the first to...
, the Philippines
Philippines
The Philippines , officially known as the Republic of the Philippines , is a country in Southeast Asia in the western Pacific Ocean. To its north across the Luzon Strait lies Taiwan. West across the South China Sea sits Vietnam...
, Madagascar and South India.
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
Air gun
An air gun is a rifle , pistol , or shotgun that fires projectiles by means of compressed air or other gas, in contrast to a firearm, which burns a propellant. Most air guns use metallic projectiles as ammunition. Air guns that only use plastic projectiles are classified as airsoft...
and not modeled after Asian 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
Rudolf Diesel
Rudolf Christian Karl Diesel was a German inventor and mechanical engineer, famous for the invention of the diesel engine.-Early life:Diesel was born in Paris, France in 1858 the second of three children of Theodor and Elise Diesel. His parents were Bavarian immigrants living in Paris. Theodor...
in his creation of the diesel engine
Diesel engine
A diesel engine is an internal combustion engine that uses the heat of compression to initiate ignition to burn the fuel, which is injected into the combustion chamber...
around 1892.
The device is still crafted and sold in the west by a few individuals who also supply larger survival and bushcraft companies.
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.
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 dissipate 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
Diesel engine
A diesel engine is an internal combustion engine that uses the heat of compression to initiate ignition to burn the fuel, which is injected into the combustion chamber...
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
Hot bulb engine
The hot bulb engine, or hotbulb or heavy oil engine is a type of internal combustion engine. It is an engine in which fuel is ignited by being brought into contact with a red-hot metal surface inside a bulb....
, 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
Compression ratio
The 'compression ratio' of an internal-combustion engine or external combustion engine is a value that represents the ratio of the volume of its combustion chamber from its largest capacity to its smallest capacity...
of about 25 to 1. This compares with about 20:1 for a modern diesel engine and 10:1 - 11.5:1 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
Char cloth
Char cloth is a swatch of fabric made from vegetable fiber that has been converted via pyrolysis into a slow-burning fuel of very low ignition temperature. It is capable of being ignited by a single spark that can in turn be used to ignite a tinder bundle to start a fire...
or amadou
Amadou
Amadou is a spongy, flammable substance prepared from bracket fungi. The species generally used is Fomes fomentarius which in English is also called horse's hoof fungus or tinder fungus. The amadou layer can be found on top of the fungus just below the outer skin and above the pores...
work well as tinder in the fire piston. The tinders that work best in the fire piston combust at a very low temperature. Cotton fibres for example combust at 235 °C (455 °F) and will light in fire pistons.
The physics and heat enthalpy
Enthalpy
Enthalpy is a measure of the total energy of a thermodynamic system. It includes the internal energy, which is the energy required to create a system, and the amount of energy required to make room for it by displacing its environment and establishing its volume and pressure.Enthalpy is a...
equations of a fire piston are explained at General Problems 7.74
External links
- The Firepiston: Ancient Firemaking Machine
- University of Bristol, School of Chemistry: The Fire Piston
- A collection of antique fire syringes
- An equation describing the change in temperature during compression
- Photographs of a fire syringe
- review fire piston
- The Naked Scientists - How a fire piston works
- WonderHowTo - Make your own fire piston