One of the first were Russian engineers, who in 1708 proposed to Peter I to test an explosive device, which was a barrel of water in which a hermetically sealed powder charge was kept. A wick came out - at the moment of danger they lit it and threw this device into the hearth of the fire. In another version, Peter I himself proposed to install barrels of water in the powder magazines, in which the black powder was hidden. The whole cellar was supposed to be simply entangled with fire-conducting cords connected to “charged” water barrels. Actually, this is how the prototype of a modern automated fire extinguishing system with active modules (water barrels) and sensors for detecting and transmitting a signal to start appeared. But the idea of Peter I was so ahead of progress that Russia did not even dare to undertake full-scale tests.
Even in the 19th century, fires were a terrible disaster. The Great Fire of Boston. 1872, USA
But in Germany, Zachary Greil from Ausburg in 1715 developed a similar "water bomb", which, exploding, suppressed fire with powder gases and sprayed water. The witty idea went down in history under the name "Greyl's barrel fire extinguisher". The Englishman Godfrey brought such a design to complete automatism, who in 1723 placed barrels of water, gunpowder and fuses in the zones of the alleged fire. As planned by the engineer, the flame from the fire was supposed to independently ignite the cord with all the ensuing consequences.
But the firefighters of those times did not live with water alone. So, Colonel Roth from Germany proposed to extinguish fires using powdered alum (double metal salts), which were sealed in a barrel and filled with gunpowder. Artillery officer Roth tested his creation in 1770 in Essling when he detonated a powder bomb inside a burning store. In different sources, the consequences of such an experiment are described in different ways: in some they mention the effective extinguishing of the flame with powder, and in the second they write that after the explosion, no one was able to find the location of the previously burning store. Be that as it may, the methods of powder extinguishing with fire-extinguishing salts were recognized as successful and from the end of the 18th century they entered into practice.
External view and section of "Pozharogas" Sheftal
In Russia, at the turn of the 19th and 20th centuries, perhaps one of the most advanced designs of automatic powder explosive fire extinguishers, "Pozharogas", was developed. The author NB Sheftal suggested filling the fire-extinguishing grenade with bicarbonate of soda, alum and ammonium sulfate. The design consisted of a cardboard body (1) filled with a flame extinguishing compound (2). Also inside was a cardboard cup (3), into which the gunpowder (5) and the powder layer were pressed, a fuse cord (6) was pulled to the powder charge, from which the powder thread (7) departed. As a precautionary measure, firecrackers were provided on the fuse-cord (10). In an insulated tube (9) covered with a case (8), a cord and firecrackers were placed. "Pozharogasy" were not easy - modifications for 4, 6 and 8 kg went in the series. How did such a specific grenade work? As soon as the fuse-cord ignited, the user had 12-15 seconds to use the Fireogas for its intended purpose. Firecrackers on the cord exploded every 3-4 seconds, notifying firefighters about the imminent detonation of the main charge of gunpowder.
From left to right: Theo, Rapid and Blitzfackel fire extinguishers
It was also possible to extinguish the flame with powder with the help of primitive devices, which received the general name of torches. Advertising lavishly praised the ability of torches to fight fires, but the bright names were especially memorable: "Antipyr", "Flame", "Death to Fire", "Phoenix", "Blitzfackel", "Final" and others. A typical fire extinguisher of this format was the Teo, equipped with bicarbonate of soda mixed with insoluble dyes. In fact, the procedure for extinguishing with such torches consisted of falling asleep with powders of an open flame, which blocked the access of oxygen and, in some versions, suppressed the fire with the emitted inert gases. Usually torches were hung from nails indoors. In the event of a fire, they were pulled off the wall, while the funnel was opened to eject the powder. And then, with sweeping movements, it was simply required to pour out the contents as accurately as possible into the fire site. Compositions for equipping torches differed in extreme variety - each manufacturer tried to come up with its own "zest". Mainly soda was used as the main filler of the fire extinguisher, but the spectrum of impurities was wide - table salt, phosphates, nitrates, sulfates, mummy, ocher and iron oxide. Additives that prevent caking were infuser earth, refractory clay, gypsum, starch, or silica. One of the advantages of such primitive devices was the ability to extinguish burning wiring. The rise in popularity of fire extinguishing torches took place at the turn of the 19th-20th centuries, but due to low efficiency and low charge capacity, it quickly faded away. Various kinds of "Flameboy" and "Blitzfackel" were replaced by fire-extinguishing grenades equipped with solutions of special salts. Usually these were glass cylinders or bottles with a capacity of 0.5 to 1.5 liters, in which powdered reagents were stored. For a platoon on "combat duty", the user only had to fill the grenades with water and install them in a conspicuous place in the room. On the market were also presented completely ready-to-use models, in which the solution was poured before sale.
Fire extinguishing grenades "Death to Fire" and "Grenade"
Fire extinguishing grenades "Pikhard" and "Imperial"
Manufacturers of grenades also did not have a clearly defined standard for equipping a fire extinguisher - alum, borax, Glauber's salt, potash, ammonia, calcium chloride, sodium and magnesium, soda and even liquid glass were used. Thus, the Venus fire-extinguishing cylinder was made of thin green glass, and it was filled with 600 grams of a mixture of ferrous sulfate and ammonium sulfate. A similar pomegranate "Gardena" with a total weight of about 900 grams, contained a solution of sodium chloride and ammonia.
Suspended Venus fire-extinguishing cylinders and Gardena grenades
The method of using fire extinguishing grenades was not particularly difficult - the user either poured the contents onto the fire, or threw it with effort into the fire. The flame extinguishing effect was based on the cooling ability of solutions, as well as a thin film of salts, which blocked the access of oxygen to burning surfaces. In addition, many salts from thermal exposure decomposed to form gases that did not support combustion. Over time, consumers realized the utopian nature of such fire extinguishers: the small capacity did not allow to suppress at least some serious fire, and fragments of glass scattering during use on all sides often injured users. As a result, this technique not only fell out of circulation at the beginning of the 20th century, but was even banned in some countries.
The stationary automatic alkaline-acid fire extinguisher "Chef" by engineer Falkovsky became a much more serious application for fire fighting. He presented it at the beginning of the last century and it consisted of two parts: the fire extinguisher itself and the associated electrical signaling device, as well as the apparatus for activating the fire extinguisher. Falkovsky suggested extinguishing with a 66-kilogram aqueous solution of bicarbonate of soda with 850 grams of sulfuric acid. Naturally, the acid and soda were merged only before extinguishing. For this, a flask with acid was placed in a reservoir with water and soda, to which a rod impactor was attached. The latter was powered by a massive weight held by a fusible Wood's alloy thermostat plug. This alloy contains lead, cadmium, tin and bismuth, and melts already at 68.5 degrees. The thermostat is designed in the form of a frame with spring metal contacts, separated by an ebonite knife-plate, on the metal handle of which a fusible plug is soldered. From the thermostat contacts, the signal is transmitted to the control panel, which emits sound and light signals (with an electric bell and a light bulb). As soon as Wood's alloy "gave a leak" from the high temperature, an alarm went off, and the rod impactor fell on the flask with acid. Then the classic reaction of neutralization was launched with the release of hundreds of liters of carbon dioxide and a huge volume of water foam, which suppressed almost any flame in the area.
Over time, foam extinguishing installations and famous sprinklers have become a real mainstream of fire automation.
