Construction of a crosswalk using polymer modified cement slurry

A propane torch is a

tool A tool is an object that can extend an individual's ability to modify features of the surrounding environment or help them accomplish a particular task. Although many animals use simple tools, only human beings, whose use of stone tools dates ba ...

normally used for the application of

flame A flame (from Latin ''flamma'') is the visible, gaseous part of a fire. It is caused by a highly exothermic chemical reaction taking place in a thin zone. When flames are hot enough to have ionized gaseous components of sufficient density they ...

heat In thermodynamics, heat is defined as the form of energy crossing the boundary of a thermodynamic system by virtue of a temperature difference across the boundary. A thermodynamic system does not ''contain'' heat. Nevertheless, the term is al ...

which uses

propane Propane () is a three-carbon alkane with the molecular formula . It is a gas at standard temperature and pressure, but compressible to a transportable liquid. A by-product of natural gas processing and petroleum refining, it is commonly used a ...

, a hydrocarbon

gas Gas is one of the four fundamental states of matter (the others being solid, liquid, and plasma). A pure gas may be made up of individual atoms (e.g. a noble gas like neon), elemental molecules made from one type of atom (e.g. oxygen), or ...

, for its

fuel A fuel is any material that can be made to react with other substances so that it releases energy as thermal energy or to be used for work. The concept was originally applied solely to those materials capable of releasing chemical energy but ...

and ambient air as its combustion medium. Propane is one of a group of by-products of the

natural gas Natural gas (also called fossil gas or simply gas) is a naturally occurring mixture of gaseous hydrocarbons consisting primarily of methane in addition to various smaller amounts of other higher alkanes. Low levels of trace gases like carbo ...

and

petroleum Petroleum, also known as crude oil, or simply oil, is a naturally occurring yellowish-black liquid mixture of mainly hydrocarbons, and is found in geological formations. The name ''petroleum'' covers both naturally occurring unprocessed crud ...

industries known as

liquefied petroleum gas Liquefied petroleum gas (LPG or LP gas) is a fuel gas which contains a flammable mixture of hydrocarbon gases, specifically propane, propylene, butylene, isobutane and n-butane. LPG is used as a fuel gas in heating appliances, cooking e ...

(LPG). Propane and other fuel torches are most commonly used in the manufacturing, construction and

metal-working Metalworking is the process of shaping and reshaping metals to create useful objects, parts, assemblies, and large scale structures. As a term it covers a wide and diverse range of processes, skills, and tools for producing objects on every scale ...

industries.

Fuels

Propane is often the fuel of choice because of its low price, ease of storage and availability, hence the name "propane torch". The gasses

MAPP gas MAPP gas was a trademarked name, belonging to The Linde Group, a division of the former global chemical giant Union Carbide, for a fuel gas based on a stabilized mixture of methylacetylene (propyne), propadiene and propane. The name comes from th ...

and Map-pro are similar to propane, but burn hotter. They are usually found in a yellow canister, as opposed to propane's blue, black, or green. Alternative fuel gases can be harder to store and more dangerous for the user. For example,

acetylene Acetylene (systematic name: ethyne) is the chemical compound with the formula and structure . It is a hydrocarbon and the simplest alkyne. This colorless gas is widely used as a fuel and a chemical building block. It is unstable in its pure ...

needs a porous material mixed with acetone in the tank for safety reasons and cannot be used above a certain pressure and withdrawal rate.

Natural gas Natural gas (also called fossil gas or simply gas) is a naturally occurring mixture of gaseous hydrocarbons consisting primarily of methane in addition to various smaller amounts of other higher alkanes. Low levels of trace gases like carbo ...

is a common fuel for household cooking and heating but cannot be stored in liquid form without cryogenic refrigeration.

Mechanism

Small air-only torches normally use the

Venturi effect The Venturi effect is the reduction in fluid pressure that results when a fluid flows through a constricted section (or choke) of a pipe. The Venturi effect is named after its discoverer, the 18th century Italian physicist, Giovanni Battista V ...

to create a pressure differential which causes air to enter the gas stream through precisely sized inlet holes or intakes, similar to how a car's

carburetor A carburetor (also spelled carburettor) is a device used by an internal combustion engine to control and mix air and fuel entering the engine. The primary method of adding fuel to the intake air is through the venturi tube in the main meteri ...

works. The fuel and air mix sufficiently, but imperfectly, in the burner's tube before the flame front is reached. The flame also receives some further oxygen from the air surrounding it. Oxygen-fed torches use the high pressure of the stored oxygen to push the oxygen into a common tube with the fuel.

Uses

Propane torches are frequently employed to

solder Solder (; NA: ) is a fusible metal alloy used to create a permanent bond between metal workpieces. Solder is melted in order to wet the parts of the joint, where it adheres to and connects the pieces after cooling. Metals or alloys suitable ...

copper water pipes. They can also be used for some low temperature

welding Welding is a fabrication (metal), fabrication process that joins materials, usually metals or thermoplastics, by using high heat to melt the parts together and allowing them to cool, causing Fusion welding, fusion. Welding is distinct from lower ...

applications, as well as for

brazing Brazing is a metal-joining process in which two or more metal items are joined together by melting and flowing a filler metal into the joint, with the filler metal having a lower melting point than the adjoining metal. Brazing differs from we ...

dissimilar metals together. They can also be used for annealing, for heating metals up in order to bend them more easily, bending glass, and for doing

flame test A flame test is an analytical procedure used in chemistry to detect the presence of certain elements, primarily metal ions, based on each element's characteristic flame emission spectrum (which may be affected by the presence of chloride ion ...

Complete and incomplete combustion

With oxygen/propane torches, the air/fuel ratio can be much lower. The

stoichiometric Stoichiometry refers to the relationship between the quantities of reactants and products before, during, and following chemical reactions. Stoichiometry is founded on the law of conservation of mass where the total mass of the reactants equal ...

equation for complete combustion of propane with 100%

oxygen Oxygen is the chemical element with the symbol O and atomic number 8. It is a member of the chalcogen group in the periodic table, a highly reactive nonmetal, and an oxidizing agent that readily forms oxides with most elements as wel ...

is: :C₃H₈ + 5 (O₂) → 4 (H₂O) + 3 (CO₂) In this case, the only products are CO₂ and

water Water (chemical formula ) is an inorganic, transparent, tasteless, odorless, and nearly colorless chemical substance, which is the main constituent of Earth's hydrosphere and the fluids of all known living organisms (in which it acts as a ...

. The balanced equation shows to use 1

mole Mole (or Molé) may refer to: Animals * Mole (animal) or "true mole", mammals in the family Talpidae, found in Eurasia and North America * Golden moles, southern African mammals in the family Chrysochloridae, similar to but unrelated to Talpida ...

of propane for every 5 moles of oxygen. With air/fuel torches, since air contains about 21% oxygen, a very large ratio of air to fuel must be used to obtain the maximum flame temperature with air. If the propane does not receive enough oxygen, some of the carbon from the propane is left unburned. An example of incomplete combustion that uses 1 mole of propane for every 4 moles of oxygen: :C₃H₈ + 4 (O₂) → 4 (H₂O) + 2 (CO₂) + 1 C The extra carbon product will cause

soot Soot ( ) is a mass of impure carbon particles resulting from the incomplete combustion of hydrocarbons. It is more properly restricted to the product of the gas-phase combustion process but is commonly extended to include the residual pyrolysed ...

to form, and the less oxygen used, the more soot will form. There are other unbalanced ratios where incomplete combustion products such as

carbon monoxide Carbon monoxide (chemical formula CO) is a colorless, poisonous, odorless, tasteless, flammable gas that is slightly less dense than air. Carbon monoxide consists of one carbon atom and one oxygen atom connected by a triple bond. It is the simple ...

(CO) are formed, such as: :6 (C₃H₈) + 29 (O₂) → 24 (H₂O) + 16 (CO₂) + 2 CO

Flame temperature

An air-fed torch's maximum adiabatic flame temperature is assumed to be around . However, a typical primary flame will only achieve to . Oxygen-fed torches can be much hotter at up to .

References

Bibliography

* *

External links

How to Silver Solder Steel with a Propane Torch

How To properly Heat Up Copper Pipe Using A Propane Torch
{{DEFAULTSORT:Propane Torch Burners Metalworking tools Welding

Torch A torch is a stick with combustible material at one end, which is ignited and used as a light source. Torches have been used throughout history, and are still used in processions, symbolic and religious events, and in juggling entertainment. In ...