Classifications

• • A—HUMAN NECESSITIES
  • A62—LIFE-SAVING; FIRE-FIGHTING
  • A62D—CHEMICAL MEANS FOR EXTINGUISHING FIRES OR FOR COMBATING OR PROTECTING AGAINST HARMFUL CHEMICAL AGENTS; CHEMICAL MATERIALS FOR USE IN BREATHING APPARATUS
  • A62D1/00—Fire-extinguishing compositions; Use of chemical substances in extinguishing fires
  • A62D1/0028—Liquid extinguishing substances
  • A62D1/005—Dispersions; Emulsions

Definitions

• a general use fire-extinguishing composition comprising a saturated liquid phase and dispersed therein are undissolved particulate solids present in a concentration which increases the fire-extinguishing eifectiveness of the saturated aqueous phase.
• the flowability of the composition is maintained by a dispersing agent such as clay.
• This invention relates to compositions useful for extinguishing fires, in particular to such compositions which are effective against dry fires (wood, paper, rags, etc.), fires of highly inflammable liquids, such as hydrocarbons, and mixed fires.
• potassium and sodium salts have useful fire extinguishing properties, and may be used either in the form of powder or in the form of an aqueous solution to fight fires.
• alkali metal bicarbonates are very often used, but whereas they are very etfective against fires of hydrocarbons or other inflammable liquids, they have a drawback common to all fire extinguishing powders; they have but little effect against dry fires, and give only poor results against mixed fires.
• An object of this invention is to provide firefighting compositions which have at one and the same time the advantages of the powders and of the solutions and are in this way of a very general use. Another object is to provide fire-extinguishing compositions which can be readily used after long storage periods.
• a broad inventive concept of a fire-extinguishing aqueous dispersion to saturation comprising water, fire-extinguishing means dissolved in said water, thereby forming an aqueous phase, and particulate solids dispersible in said aqueous phase, said particulate solids being present in a sufiicient concentration to increase the fire-extinguishing effectiveness of said aqueous phase.
• the fire-extinguishing composition of the present invention comprises an aqueous dispersion containing in dissolved and undissolved form at least one alkali metal salt, specifically potassium and/or sodium salts, with the provision that a potassium salt is present in at least one form.
• alkali metal salt specifically potassium and/or sodium salts
• Anions of such salts include, for example, chloride, phosphates, sulfate, carbonate and/or bicarbonate.
• the undissolved solids are in particulate form and maintained in suspension in an aqueous solution in equilibrium with said solid.
• This suspension is preferably maintained by the addition of a minor quantity of a dispersing agent.
• active salt is defined as the total quantity of salt (or salts) of potassium or potassium and sodium, and the general term alkali metal salts is used to designate either the potassium salts or the mixture of potassium and sodium salts as defined above.
• the salts are subjected to particle size diminution, for example by grinding, so that substantially all the particles have a size less than 200 microns; preferably, the size of at least by weight of the particles is lower than microns, and advantageously about between 20 and 50% of the total solids has a particle size less than 44 microns.
• the particles can be extremely fine without presenting any drawback; still, for commercial purpose, substantially all are larger than 20 microns, which is the lower limit that can be obtained with industrial grinders without increasing the grinding costs inordinately.
• grinding costs can be reduced by first preparing an aqueous solution of commercial-grade alkali metal salts, and then adding to said solution the finely ground salt to be maintained in suspension therein.
• bicarbonate which has been treated with an iron salt according to the process disclosed in copending application Ser. No. 330,549, filed Dec. 16, 1963, said application having a common inventor and the same assignee as this application, and now Patent 3,350,306, issued Oct. 31, 1967.
• the suspensions used contain from about 10 to 60 parts of undissolved active salt per 100 parts by weight of solution, and preferably from about 20 to 35 parts, for indeed it has been observed that when the suspension contains less than about 10% of active salt by weight of solution, the extinguishing power of the composition is practically equivalent to that of the solution itself, and that when the suspension contains more than 60% of active salt, by weight of solution, the flowing and spraying operations become difficult problems.
• the dispersing agents used can be water-soluble salts, such as alkali metaphosphates and/or alkali metal silicates, the latter salts either remaining in the dissolved form or precipitating in form of colloidal silica according to the nature of the active salt present.
• agents with little or no water solubility can be used, such as silicoaluminates, for example all the varieties of natural or synthetic clays, such as montmorillonite, bentonite, attapulgite etc., and/or magnesium carbonates.
• more or less basic magnesium carbonate in form of extremely fine particles can be precipitated in the suspension itself by adding a water-soluble magnesium salt, preferably a magnesium halogenide, to the aqueous solution containing an alkali metal carbonate and/or bicarbonate.
• a water-soluble magnesium salt preferably a magnesium halogenide
• technical grade magnesium carbonates can be used, for example very finely divided products commonly sold as light magnesium carbonate.
• the particle size of the dispersing agents present in the suspension must not be higher than 5 microns but it can be much less even down to colloidal dimensions.
• the dispersing agents must be compatible with the ingredients of the composition and must not thicken the composition too much, so that it may be sprayed easily out of the extinguishing apparatus.
• the quantity of dispersing agent required is always relatively minor and, in general, less than 100 grams of dispersant per liter of suspension is enough to obtain stable suspensions of active alkali metal salt.
• the quantity of compound added to obtain dispersion depends mainly on the nature of the compound used, water-soluble products being employed in relatively higher quantites than insoluble ones.
• Stable suspensions are obtained by using about 20 to 50 grams of alkali metal silicate or about 20 to 100 grams of magnesium halide per liter of suspension. Under the same conditions, quantities varying from to 40 g./1. of dispersing agents added in substantially insoluble form generally give very satisfactory results. In any event, it is apparent that the addition of greater or lesser amounts will nevertheless yield at least a finite degree of dispersing activity.
• the stability of the stored suspensions is sufficient to prevent the crystals of active salt from agglomerating, and their viscosity is low enough not to hinder the spraying of the composition onto a fire.
• the very fine particles in the suspension keep the active salt from settling or reduce its tendency to settle to such an extent that a very mild stirring will put it back into suspension. Even after a long storage period, the solids of the suspensions are still in the finely divided form which allows for a better extinction when the suspensions are applied to fires.
• the fire-extinguishing suspensions disclosed in the present invention can be employed in any of the usual types of apparatus used for spraying water or projecting powders, which may be done by using gas pressure or any other means, such as a pump connected to a tank.
• any suitable type of apparatus for projecting a suspension may be used for fighting fires with these compositions.
• the fire-fighting compositions of the invention remain eifective within a wide range of temperatures.
• extinguishing tests were performed with a suspension containing as active salt a mixture of potassium bicarbonate and carbonate to which sodium silicate had been added as dispersing agent.
• An extinguisher containing 8 liters of freshly prepared suspension was used to carry out 6 successive extinctions on a fire which was burning in a round pan of 0.7 m? area, containing 21 liters of essence F (mineral spirits having a boiling range from 100 to 160 C. under normal pressure).
• Additional additives common to prior art fire-extinguishing compositions can also be advantageously included in the compositions disclosed in the present invention, such as, for instance, wetting agents, corrosion inhibitors, substances which improve the spraying qualities, etc. It is obvious, however, that these additives, though added in minor amounts, must be compatible with the main constituents of the composition.
• wetting agent such as, for example, an oxyethylene alkyl phenol, quaternary ammonium salts, or a product obtained from the condensation of ethylene oxide and a primary aliphatic amine in which the aliphatic radical contains from 8 to 22 carbon atoms, etc.
• a wetting agent such as, for example, an oxyethylene alkyl phenol, quaternary ammonium salts, or a product obtained from the condensation of ethylene oxide and a primary aliphatic amine in which the aliphatic radical contains from 8 to 22 carbon atoms, etc.
• wetting agent such as, for example, an oxyethylene alkyl phenol, quaternary ammonium salts, or a product obtained from the condensation of ethylene oxide and a primary aliphatic amine in which the aliphatic radical contains from 8 to 22 carbon atoms, etc.
• 0.5 to 3% of wetting agent by weight relative to the weight of suspension is used.
• a typical corrosion inhibitor for this system is a compound sold under the trademark Norust O.C. and which is a fatty amine derivative.
• a small quantity of an aliphatic alcohol having a low molecular weight, for instance containing from 1 to 3 carbon atoms, can be advantageously added to the suspensions of the invention.
• denatured alcohol which is a product of a very low cost, is particularly advantageous to facilitate the spraying noticeably, and thereby improve the extinguishing effect.
• Quantites of alcohol ranging from about 0.5 to 5% by weight of suspension have been found to give excellent results in most cases.
• EXAMPLE 1 An aqueous saturated potassium chloride solution was prepared with a commercial grade salt containing KCl. To 10 liters of said solution were added 3 kg. of potassium chloride ground to a particle size of less than 104 microns, and 0.25 liter of a wetting agent (obtained by condensation of ethylene oxide with an aliphatic amine).
• EXAMPLE 2 An aqueous suspension of potassium chloride was prepared under exactly the same conditions as in Example 1, with the further addition of 10 g./l. of a swelling-type clay sold under the trademark Clarsil. The resulting suspension was stored quiescently for 3 months at outdoor temperature.
• the suspension was poured into 'a cylindrical glass tube of 0.10 m. diameter and a height of 1.20 m., another small tube measuring 2 mm. inner diameter being inserted therein through which gas under pressure can be injected.
• the tube is filled with 8 liters of the potassium chloride suspension, the column of liquid reaches a height of about 100 cm.
• EXAMPLE 3 First a solution was prepared by dissolving 50 kg. of technical grade potassium carbonate in 100 liters of water. To the resultant cooled solution were then added 25 kg. of potassium bicarbonate containing 2%iron sulfate, the 25 kg. being so ground that about 50% of the particles has a size less than 44 microns and 90% less than 74 microns. The mixture was kept well agitated, and then a further additions was made of 13 liters of a magnesium chloride aqueous solution containing 450 g./l. of MgCl and lastly 0.3 liter 80% ethyl alcohol.
• EXAMPLE 4 A suspension containing potassium carbonate and bicarbonate was prepared under the same conditions as in Example 3 but with a different dispersing agent and a different additive.
• the dispersing agent used was sodium silicate. 25 cc. of a commercial sodium silicate solution (density 1.3) were added to 1 liter of suspension. A further addition of 5 cc. of a wetting agent (product obtained from the condensation of ethylene oxide and an aliphatic amine) and of 5 cc. of methyl alcohol (commercial grade), per liter of suspension, was then made.
• the suspension was placed in a refrigerator and kept at C. for different periods of time, then extinguishing tests were performed under the same conditions as with the freshly prepared solution.
• the table hereunder illustrates the average number of extinguishments obtained with the contents of one extinguisher (8 liters) on a fire of essence P which had been left to burn for 1 minute in a round pan of 0.7 m? area.
• the extinguishing operations were performed with an extinguisher coming out of a refrigerator, that is to say, with a suspension having a temperature very close to 20 C.
• EXAMPLE 5 A solution was prepared by dissolving 2.5 kg. of potassium metaphosphate in 10 liters of water. To this solution were added 2 kg. of the same metaphosphate, but ground to a particle size of less than 104 microns. To this suspension, 10 g./l. of clay and 20 cc. of wetting agent were added.
• EXAMPLE 6 10 kg. of technical grade disodium phosphate, Na HPO were introduced into 10 liters of water; then, after most of the phosphate was dissolved, 10 kg. of technical grade potassium bicarbonate ground so that 50% of the particles had a size less than 44 microns and less than 74 microns, were added. 0.5 liter of wetting agent obtained by condensation of ethylene oxide and an aliphatic amine were also added to the resulting suspension.
• EXAMPLE 7 10 kg. of technical grade sodium sulfate (Na SO 10H O) were added to 40 liters of water, then after stirring so as to dissolve most of the sulfate, 10 kg. of technical grade potassium bicarbonate of the same particle size as in Example 1 were added.
• the resulting suspension was then poured into an extinguisher of the commercial type used for spraying water (contents 6 liters) using a cartridge containing 60 g. of C0
• the apparatus has a discharge nozzle such that the time necessary to empty the extinguisher is 26 seconds with said suspension.
• the apparatus filled with the suspension was used against a fire built of 15 kg. of wood in the form of small sticks of about 10 cm. length and about 1 cm. thickness, disposed within a casing made out of metal wire netting of a length of 1.50 m., a width of 0.10 m., and a height of 0.55 m.
• the wood was ignited by the combustion of 0.6 liter of essence F placed in a metal pan under the stack of wood.
• the essence F was left to burn for 3.5 minutes, the metal pan was then removed, and after another 30 seconds the fire, which was then burning fiercely, was attacked. After the apparatus had emptied, there were no more ignited spots left in the partly consumed mass.
• EXAMPLE 8 15 kg. of technical grade potassium carbonate were dissolved in 30 liters of water. 7.5 kg. of sodium bicarbonate ground so that 90% of the particles had a size less than 50 microns, were added to the solution.
• the resulting suspension was kept agitated while sodium silicate of 1.3 density (1.35 kg.), denatured ethyl alcohol (1 liter), and a wetting agent (0.6 liter) were added.
• EXAMPLE 9 A solution was prepared by dissolving 88 kg. of technical grade potassium carbonate and 16 kg. of technical grade potassium bicarbonate in 200 liters of water at 20 C., to which was added a dispersing agent consisting of 10 kg. of water-soluble potassium metaphosphate.
• Example 2 Contents 8 liters.
• a fire of essence F left to burn for 1 minute in a round pan of 1.08 m? area was extinguished three times running. Average time for extinguishment was 5 seconds.
• the same results were obtained with extinguishers coming from a refrigerator, i.e., with a suspension at a temperature of about l7 C.
• EXAMPLE 10 An aqueous suspension of potassium sulfate was pre pared under the same conditions as in Example 9, but using as dispersing agent 10 kg. of swelling clay and no wetting agent.
• the resulting suspension was projected onto a pool of essence F of 4 m? area which had been left to burn for 1 minute.
• the apparatus used for projecting the suspension comprised a tank, a pump having a 17 bar dis-.
• magnesium bromide or fluoride or iodide can be employed instead of magnesium chloride under the same conditions.
• other fire-extinguishing salts can be substituted for the ones specifically disclosed.
• a fire-extinguishing aqueous dispersion consisting essentially of water, normally solid fire-extinguishing solids dissolved to saturation in said water, thereby forming a saturated aqueous phase, and undissolved fire-extinguishing particulate solids dispersed in said saturated aqueous phase, said undissolved particulate solids being in equilibrium with said saturated aqueous phase, and being present in a sufficient concentration to increase the fire-extinguishing effectiveness of said saturated aqueous phase, said particulate solids having a particle size of less than about 200 microns, and said concentration being about 10-60% by weight based on the saturated aqueous phase.
• a fire-extinguishing aqueous dispersion comprising water and an alkali metal salt selected from the group consisting of chlorides, phosphates, sulfates, carbonates, bicarbonates, and mixtures thereof with the provisions that at least a percentage of said alkali metal salt is a potassium salt; that a portion of said alkali metal salt is dissolved in said water, thereby forming an aqueous phase; and that another portion of said alkali metal salt is suspended in the aqueous dispersion in the form of undissolved fire-extinguishing particulate solids which are present in a sufficient concentration to increase the fireextinguishing effectiveness of said aqueous phase, said particulate solids having a particle size of less than about 200 microns, and said concentration being about 1060% by weight based on the saturated aqueous phase.
• an alkali metal salt selected from the group consisting of chlorides, phosphates, sulfates, carbonates, bicarbonates, and mixtures
• a method of extinguishing fires which method comprises the step of applying to a fire a fire-extinguishing aqueous dispersion as defined by claim 1.
• a method of extinguishing fires which method comprises the step of applying to a fire a fire-extinguishing aqueous dispersion as defined by claim 2.
• a method of extinguishing fires which method comprises the step of applying to a fire a fire-extinguishing aqueous dispersion as defined by claim 3.
• a method of extinguishing fires which method comprises the step of applying to a fire a fire-extinguishing aqueous dispersion as defined by claim 4.
• a method of extinguishing fires which method com-prises the step of applying to a fire a fire-extinguishing aqueous dispersion as defined by claim 5.
• a method of extinguishing fires which method comprises the step of applying to a fire a fire-extinguishing aqueous dispersion as defined by claim 6.
• a method of extinguishing fires which method comprises the step of applying to a fire a fire-extinguishing aqueous dispersion as defined by claim 7.
• a method of extinguishing fires which method 10 comprises the step of applying to a fire a fire-extinguishing aqueous dispersion as defined by claim 8.
• a method of extinguishing fires which method comprises the step of applying to a fire a fire-extinguishing aqueous dispersion as defined by claim 9.
• a method of extinguishing fires which method comprises the step of applying to a fire a fire-extinguishing aqueous dispersion as defined by claim 10.
• a method of extinguishing fires which method comprises the step of applying to a fire a fire-extinguishing aqueous dispersion as defined by claim 11.
• a method of extinguishing fires which method comprises the step of applying to a fire a fire-extinguishing aqueous dispersion as defined by claim 12.
• a method of extinguishing fires which method comprises the step of applying to a fire a fire-extinguishing aqueous dispersion as defined by claim 13.
• a method of extinguishing fires which method comprises the step of applying to a fire a fire-extinguishing aqueous dispersion as defined by claim 14.
• a method of extinguishing fires which method comprises the step of applying to a fire a fire-extinguishing aqueous dispersion as defined by claim 15.
• a method of extinguishing fires which method comprises the step of applying to a fire a fire-extinguishing aqueous dispersion as defined by claim 16.
• a method of extinguishing fires which method comprises the step of applying to a fire a fire-extinguishing aqueous dispersion as defined by claim 17.
• a method of extinguishing fires which method comprises the step of applying to a fire a fire-extinguishing aqueous dispersion as defined by claim 18.
• a method of extinguishing fires which method comprises the step of applying to a fire a fire-extinguishing aqueous dispersion as defined by claim 19.
• a method of extinguishing fires which method comprises the step of applying to a fire a fire-extinguishing aqueous dispersion as defined by claim 20.

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• Chemical & Material Sciences (AREA)
• Dispersion Chemistry (AREA)
• Chemical Kinetics & Catalysis (AREA)
• General Chemical & Material Sciences (AREA)
• Business, Economics & Management (AREA)
• Emergency Management (AREA)
• Fire-Extinguishing Compositions (AREA)

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Citations (4)

• 1964
  • 1964-04-17 FR FR971231A patent/FR85910E/fr not_active Expired
  • 1964-12-22 LU LU47637A patent/LU47637A1/xx unknown
  • 1964-12-31 SE SE15926/64A patent/SE309537B/xx unknown
• 1965
  • 1965-01-11 NL NL6500273A patent/NL6500273A/xx unknown
  • 1965-01-13 DE DES94999A patent/DE1218884B/de active Pending
  • 1965-01-27 GB GB3571/65A patent/GB1086583A/en not_active Expired
  • 1965-01-29 CH CH126465A patent/CH447829A/fr unknown
  • 1965-01-29 BE BE659055A patent/BE659055A/xx unknown
  • 1965-03-02 US US436642A patent/US3425939A/en not_active Expired - Lifetime

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