Propane torch

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A propane torch is a tool normally used for fire or heat applications that use propane, hydrocarbon gas for fuel. Propane is one of a group of by-products from the natural gas and petroleum industries known as liquefied petroleum gas or LPG. Propane and other fuel torches are most commonly used in manufacturing, construction and metal-working industries.

The term "propane torch" may refer to anything from a small consumer-class hand-held consumer with a small installed tank or industrial torch that has a fuel tank and pure oxygen placed separately to supply fire with 100% oxygen in return for much higher temperatures , while using propane. A similar gas, known as MAPP-gas or MAP-PRO, is similar to propane, but burns hotter. Usually found in yellow tubes, not blue, black, or green propane. Propane is often the preferred fuel because of its low cost, ease of storage and availability. Alternative fuel gases can be more difficult to store and more harmful to users. For example, acetylene requires a porous material mixed with acetone in the tank for safety reasons and can not be used above certain pressure and withdrawal levels. Natural gas is a common fuel for cooking and heating households but can not be stored in liquid form without cryogenic coolant.

A small airborne torch typically uses the Venturi effect to create a pressure difference that causes air to enter the gas stream through an inlet or intake that is exactly the size, similar to how carburettors work. Fuel and air mixture are sufficient, but often imperfect, in the burner tube before the front of the fire is reached. Fire also receives some oxygen farther from the surrounding air.

The oxygenated torch uses high pressure from stored oxygen to drive oxygen to a common tube with fuel. An air torch will only burn at about 1.995 Â ° C (3.623 Â ° F), less if heat loss to the surrounding is taken into account. The oxygenated torch can heat up to 2,820 ° C (5,110 ° F), depending on the oxygen-fuel ratio. This is the theoretical maximum temperature, in reality they will always be less due to incomplete combustion, heat loss etc.

Propane torches are often used for soldering copper water pipes. They can also be used for some low temperature welding applications, as well as for brazing different metals together.

In addition to the above, a major factor in the flame temperature is the percentage of oxygen mixing with propane. With an air/fuel torch, since air contains about 21% oxygen, to get maximum fire temperature by air, a very large air to fuel ratio should be used. Even the glass-making torches, which are basically Bunsen burners with additional air pumps, can only reach a temperature of 1,100 ° C (2.010 ° F).

Video Propane torch

Incomplete and incomplete burning

With an oxygen/propane torch, the ratio of air/fuel can be much lower. The stoichiometric equation for complete propane combustion with 100% oxygen is:

C ₃ H ₈ 5 (O ₂ ) -> 4 (H ₂ O ) 3 (CO ₂ )

In this case, the only product is CO ₂ and water. The balanced equation shows to use 1 mole of propane for every 5 moles of oxygen.

It is much more difficult to achieve complete combustion with air rather than with oxygen. If propane does not receive enough oxygen, some carbon from propane is left unburned. Examples of incomplete combustion using 1 mole of propane for every 4 moles of oxygen:

C ₃ H ₈ 4 (H ₂ O ) 2 (CO ₂ ) 1 C

The additional carbon product will cause the soot to form, and the less oxygen is used, the more soot will be formed. There is another unbalanced ratio in which incomplete combustion products such as carbon monoxide (CO) are formed, such as:

6 (C ₃ H ₈ ) 29 (O ₂ ) -> 24 (H ₂ O) 16 (CO ₂ ) 2 CO

Maps Propane torch

References

Source of the article : Wikipedia