English

Adjective

1. of, or using a mixture of hydrogen and oxygen

Translations

Derived terms

• oxyhydrogen flame
• oxyhydrogen torch

Oxyhydrogen is a mixture of hydrogen and oxygen gases, typically in a 2:1 atomic ratio, the same proportion as water.

When ignited, the gas mixture converts to water vapor and releases energy, which sustains the reaction: 241.8 kJ of energy (LHV) for every mole of burned. The amount of heat energy released is independent of the mode of combustion, but the temperature of the flame varies. The maximum temperature of about 2800 °C is achieved with a pure stoichiometric mixture, about 700 degrees hotter than a hydrogen flame in air. When either of the gases is mixed in excess of this ratio, or when mixed with an inert gas like nitrogen, the heat must spread throughout a greater quantity of matter and the temperature will be lower.

Applications

Lighting

Many forms of oxyhydrogen lamps have been described, such as the limelight, which used an oxyhydrogen flame to heat a piece of lime to white hot incandescence. An oxyhydrogen torch is used in the glass industry for "fire polishing"; slightly melting the surface of glass to remove scratches and dullness.

The oxyhydrogen flame begins a short distance from the torch tip; if the distance is great enough the torch tip can remain relatively cool.

Production

A pure stoichiometric mixture is most easily obtained by water electrolysis, which uses an electric current to dissociate the water molecules:

electrolysis: 2 H2O → 2 H2 + O2

combustion: 2 H2 + O2 → 2 H2O

The energy required to generate the oxyhydrogen always exceeds the energy released by combusting it. (See Electrolysis of water:Efficiency).

Water torch

thumb|A bubbler apparatus used to mitigate potential flashback.

A water torch is a kind of oxyhydrogen torch, that is fed by oxygen and hydrogen generated on demand by water electrolysis. The device avoids the need for bottled oxygen and hydrogen, and requires electricity. Some models of water torches mix the two gases immediately after production (vs. the torch tip) making the gas mixture more accurate. Water torches must be designed to mitigate flashback by strengthening the electrolytic chamber. Use of an intermediary water bubbler eliminates potential electrolyzer damage from flashback, with a dry flashback arrestor being ineffective due to flame velocity. The bubbler is connected directly in series with the output gas. A water bubbler is sometimes referred to as a wet flashback arrestor, and effectively captures any remaining electrolyte in the output gas. Suitable electrolytes include sodium or potassium hydroxide, and other salts that ionize well. Brown's torches also used an electric arc to increase the temperature of the flame (called atomic welding):

The claimed applications of HHO and Aquygen are practically indistinguishable from the original claims of Yull Brown. The HHO trademark is associated with an unproven state of matter called magnegases, and a discredited theory about magnecules, which is the basis for a number of fraudulent claims, and third party water-fuelled car scam attempts.

References

External links

• Oxyhydrogen Welding
• Heterogeneous chain propagation in a rarefied oxyhydrogen flame (pay site)