Blow torch

From Wikipedia, the free encyclopedia

(Redirected from Blowtorch)

For other uses, see Blowtorch (disambiguation).

An old-fashioned kerosene blowtorch / blowlamp

The word blowtorch or blow torch has two meanings:

In USA usage, it is what in British English usage is called a blowlamp, various types of liquid- or gas-burning tools used for heating. They produce a much larger softer flame than an oxyacetylene torch and are used for low temperature applications - soldering, brazing, melting roof tar, or pre-heating large castings before welding, such as for repairing cast-iron cylinder heads, and for other direct rapid applications of heat such as in cooking. They cannot be used for welding, but find many other uses, not least because in their simplest form of a disposable canister feeding a hand-held torch they are very cheap and highly portable, and because the LPG fuel is very cheap in comparison to acetylene and oxygen.

Technically by USA word usage "blowtorch" must burn a liquid fuel using a vaporizer.

In technical or trade usage, modern torches are never called "blowtorches"; they are instead referred to by the type of fuel they consume. For example, a "propane torch", "acetylene-air torch", or "oxyacetylene torch". Some torches are also named for their intended use: "cutting torch" and "plumber's torch", for example.

In British English, blowtorch often means an oxy-gas torch.

[edit] Designs

Various designs exist:

A form invented in Sweden by C.R. Nyberg, patented in 1882: that form is a simple heating torch, which burns liquid fuel (such as kerosene (USA) / paraffin oil (*UK), or more recently biodiesel), with ambient atmospheric air after vaporizing it using a coiled tube passing through the flame. They take time to start, needing pre-heating with burning methylated spirit. If there is any doubt as to the integrity of the pressurized fuel tank or any of the seals in the torch, it should be treated strictly as an antique — if the tank bursts there is a very real risk of explosion or fire.
A form that burns liquid petroleum gas (e.g. propane or butane) with ambient atmospheric air.

In both sorts the fuel tank often is small and serves also as the handle, and usually is refuelled by changing the fuel tank with the liquified gas in it.

A form fed from a liquid petroleum gas cylinder via a hose, which burns the gas with ambient atmospheric air: example at this link.

[edit] Variants

A flame gun is a large type of blowlamp with built-in fuel tank, used for various purposes: weed control by controlled burn methods, melting snow and ice off walk and driveways in the winter, starting a fire, etc. It is commonly confused in word usage with a flamethrower.