Before the more reliable designs of modern fire extinguishers were developed, the options for fighting fires were largely limited to liquid-filled glass bulbs.
These bulbs, filled with a variety of fire suppressants depending on the date of manufacture and brand, were unlikely to put out anything but the smallest fires, but in a desperate situation, the extinguishers could at least buy time whether for people to escape from the fire or for fire fighters to arrive.
There were two main methods to use the extinguishers. One might throw the bulb directly at the base of a fire, glass shattering on impact. The splash of salt water might manage to quench the flames, or chemical solutions such as carbon tetrachloride would vaporize and deprive the fire of oxygen, smothering it.
Alternatively, plastic or wire cones were sold that could be affixed to walls, in which the bulb would be placed to act as something of an early sprinkler system. If there was a fire, as people evacuated from the building, one could pull a pin while passing by.
Other fixtures were made so that plastic around a triggering mechanism would melt in the heat of a fire, working on its own.
Either way, triggering a mechanism in the cone would break the glass of the extinguisher’s bulb.
Old glass bulb fire extinguishers can be difficult to find and acquire for several reasons.
First, the bulbs are destroyed by a single use, meaning that once production of the design ceased, the number of bulbs in existence became limited. The nature of a glass bulb also means that the item must be handled very carefully to keep from breaking it.
Second, because the chemicals that are stored inside many of the bulbs means that they often cannot be bought through online methods such as eBay. The bulbs that are available through such mediums are usually filled with salt water.
Glass extinguishers were developed during the 1860s. This first generation of small pint or quart-sized bulbs were made until about 1895, when they were no long recommended for use. This iteration of the design was often sealed with cement, which was covered by foil caps or paper labels.
The design saw a revival, however, in the 1910s. These were sealed using hot glass, which was used to seal the bulb’s opening with a tip or smooth, conical shape.
Aside from salt water or carbon tetrachloride, some bulbs used bicarbonate of soda or muriate of ammonia as fire suppressants.
As for the value of these items, outside of the usual variables such as condition and rarity, glass fire extinguishers tend to vary in price based on color and contents.
Though keeping a glass bulb filled with chemicals like carbon tetrachloride is rather hazardous the chemical is dangerous to inhale and has even been banned from use in consumer products in the U.S. in 1970 often the only way to see if an extinguisher contains the chemical involves breaking the sealed item open for testing.
Tempting as it may be to simply drill a hole in the bulb and drain it of hazardous chemicals, this does significantly lower the value of the item.
There are a few brands the contents or which are clearly spelled out, but for the rest, it is best to handle and store the bulbs with care.
from Chas W House http://ift.tt/24vOkn7
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