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Heating, Lighting, and Refrigeration: Lamps

To Prevent Explosions of Lamps. - One common cause of explosions is the upsetting of a lamp: hence select a lamp which has a broad, solid base rather than one that appears top heavy.

Never fill a lamp while it is burning. To avoid this, buy lamps that have no opening but the one made for the wick. While it is a convenience to have a lamp with a special opening for filling, it is not safe, as children and others will sometimes undertake to fill it while burning, which may lead to an explosion. Also, when lamps have a special opening for filling, the wick is likely to be neglected until it becomes charred and the burner gets clogged up and dirty. In this condition the lamp is very apt to explode, because the charred portion of a wick takes fire, the oil that runs over burns, and heat is generated so low down in the burner that any volatile gases thrown off by the oil may become ignited. The best oil commences to evaporate at about 110° and ignites at 125°, and this vapor, like that which rises from gasoline, benzine, or naphtha, is highly inflammable and explosive. Hence do not let a lamp stand with little oil in it, or light one which has stood partly empty for a long time.

The best lamps have an extinguisher to put out the flame, but if this is lacking, do not blow out the lamp without first turning down the wick, especially if the lamp has been burned for some time and the burner and adjacent parts are hot. The fact that you may have done this safely many times does not prove that under certain conditions a volatile gas from the oil may not meet the flame and cause explosion.

Always turn the lamp low when carrying it about, as movement from place to place in sudden draughts may bring the flame in contact with the gases that form when oil is burning, and that are more or less disturbed by the jar of walking.

Chemistry of Lamps. - The chemistry of burning kerosene is very unple. The oil is composed of two inflammable substances, a gas (hydrogen), which burns with a blue flame and a very intense heat, and a solid (carbon), which consists of very minute particles in chemical combination with the hydrogen. When the lamp is lit the flame is raised to a temperature that admits of chemical union with the oxygen of the air. The hydrogen first burns, and produces sufficient heat to allow the oxygen to ignite with the carbon. When for any reason there is an excess of oil as when a lamp is turned too high, or when the heat of the flame is reduced as when the lamp is turned too low, the heat of the burning hydrogen is not sufficient to ignite all of the solid carbon, some of which escapes in the form of a finely divided black solid, and we say that the lamp smokes. This solid carbon is what we call soot, or lampblack.

Commercial lampblack is thus obtained.

When we breathe the air, a very similar process takes place in our lungs, the oxygen of the air uniting with the waste substances in the blood and purifying them by a kind of combustion. Hence every flame in a room robs the air of a certain amount of oxygen that is essential to human life.

This process, both in the lamp and in the lungs, produces a compound of oxygen and carbon called carbon dioxygen, or carbonic-acid gas. Human beings would immediately suffocate in a room quite filled with carbonic-acid gas, as it contains no free oxygen in the form available for human use.

When unburned particles of carbon are thrown off in the form of smoke or soot, the finest of them are suspended in the air and find their way into the lungs. Nothing offers so much resistance to chemical and vital forces as pure carbon; hence these particles are difficult to dislodge and exceedingly harmful.

Meantime the lamp in burning generates a certain amount of heat. This extends from the burner to the adjacent parts of the lamp, and in many cases makes the receptacle containing the oil quite hot. The temperature of the oil is thus raised, and at a certain point it gives off a volatile inflamma ble gas similar to gasoline, benzine, or naphtha, which, if the lamp should leak, may come in contact with the open flame and cause an explosion.

Or, under certain circumstances, it may be exploded by a sharp jar.

If these facts and principles are understood and proper cautions are observed, there need be no danger in the use of kerosene. The fact that kerosene is used in practically every household and that explosions are very rare proves this, but it does not prove that proper precautions must not be observed. Modern lamps are so constructed as to reduce to a minimum the dangers due to ignorance and carelessness, but the fact that explosions do take place occasionally shows that care and intelligence are still necessary.