Title of Invention

"A PROCESS FOR THE PREPARATION OF IMPROVED FIRE EXTINGUISHER"

Abstract

This invention relates to an improved fire extinguishant for extinguishing fires such as A, B and C class of fires. The improved fire extinguishant has 70 to 80% of a single basic material. 13 to 17% of a filler. 2 to 5% of a dispersing agent and 2 to 5% of a coating agent. The fire extinguishant is prepared by heating a single basic material, filler, dispersing agent separately and then mixing and heating the same in said reaction vessel again followed by cooling and grinding. Heating said ground mixture again to obtain a reacted mixture. The mixture is reacted with a coating agent first at room temperature then at saturated steam temperature with simultaneous solvent recovery. The resulted reaction mixture is heated, cooled and sieved. The sieved reaction mixture is again heated at the temperature higher than that of the temperature followed by cooling.

Full Text

The present invention relates to an improved fire extinguishant. By way of example and without implying any limitation the fire extinguishant of the present invention can be employed for extinguishing the A, B and C class of fires. BACKGROUND OF THE INVENTION : The fire extinguishant formulations for extinguishing the A, B and C class of fires as known in the prior art, generally comprise of graphite and / or oxidised graphite. The disadvantages of such known fire extinguishant formulations, as stated above, is that the giuphite and / or oxidised graphite makes the fire extinguishant formulation conducting in nature at high applied voltaqe, which in turn makes the said formulation unsuitable for its application as fire extinguishant on the live electric wire or cable. The another type of fire extinguishant formulations for extinguishing the A, B and C class of fires as known in the prior art, generally comprise of aerosil. The disadvantages of such known fire extinguishant formulations comprising of aerosil, as stated above, is that the formulation thus resulted is very expensive, which in turn limits the application of the said products. Still another type of fire extinguishant formulations for extinguishing the A, B and C class of fires or any such fire, as known in the prior art, generally comprise of organic compounds, such as ethyl vinyl, polymers, copolymers etc. The disadvantages of such known fire extinguishant formulations comprising of organic compounds, such as ethyl vinyl, polymers, copolymers etc., as stated above, is that the decomposition products of the said formulations after extinguishing the fire of class A, B and C or any such fire thus resulted are harmful and not environment friendly, and the thermal characteristics of such fomulations are not better, which in turn limits the application of the said formulation products. Still further an another type of fire extinguishant formulations for extinguishing the A, B and C class of fires as known in the prior art, generally comprise of inorganic and / or organic silicates and / or siliconates, such as sodium aluminomethyl siloxanolates, sodium organosiliconates etc. The disadvantages of such known fire extinguishant formulations comprising of inorganic and / or organic silicates and / or siliconates, as stated above, is that the formulation thus resulted is very expensive, which in turn limits the application of the said formulation products. Yet another type of fire extinguishant formulations for extinguishing the A, B and C class of fires as known in the prior art, generally comprise of two active basic materials, such as sulphates and phosphates both. The disadvantages of such known fire extinguishant formulations comprising of two active basic materials, such as sulphates and phosphates both, as stated above, is that the formulations thus resulted in turn result in the decomposition products comprising of oxides of sulphur, which in turn are not environment friendly. i The fire extinguishant is expected to have properties, like electrical insulation, low or cold temperature resistance and as well suitable at high temperature, fire fighting efficiency and free flow characteristics, better non-hygroscopicity and still being non-toxic and resulting in the environment friendly decomposition products in addition being highly economical. The disadvantage of the fire extinguishanls known in the prior art, as described here in above, is that these do not have all these properties in one end use product. The drawback of the process of preparation of known such fire extinguishant formulations is that, these generally require heavy instrumentation and still resulting in the poor recovery of the solvent. The another drawback of process of preparation of known such fire extinguishant formulations is that, the temperature of the process of preparation is as high as 160°C or above, requiring higher amount of the energy. Still another drawbacks of known such processes having the requirements of heavy instrumentation and higher amount of energy and as well resulting in poor recovery of the solvent are that the cost of the process and hence of the end products is increased and this in turn again limit their wider applications / use of the end products among the masses. A primary object of the present invention is to propose an improved fire extinguishant, which can advantageously be employed for extinguishing fires such as of the A, B and C class of fires. Another object of the present invention is to propose an improved fire extinguishant which can advantageously be employed for extinguishing fires-' such as of the A, B and C class of fires and wherein the disadvantages and drawbacks of the prior art, as described herein above/ are eliminated totally or reduced to the major extent. Yet another object of the present invention is to propose an improved fire extinguishant which can advantageously be employed for extinguishing fires such as of the A, B and C classoffires which has better free flowing property and fire fighting efficiency, and better shelf life and high temperature and low temperature resistance. A further object of the present invention is to propose an improved fire extinguishant which can advantageously be employed for extinguishing fires such as of the A, B and C class of fires and wherein the use of graphite and / or oxidised graphite, and of aerosil, and of organic compounds, such as ethyl vinyl, polymers, copolymers etc., and of inorganic and / or organic silicates and / or siliconates, such as sodium aluminomethyl siloxanolates, sodium orrganosi1iconates etc., and active basic material, that is; sulphates are totally eliminated. A still futher • object of the present invention is to propose an improved fire extinguishant which can advantageously be employed for extinguishing fires such as of the A, B and C Class of fires and wherein the end use product is non-conducting in nature even at high applied voltage and can thus be advantageously employed for applications as fire extinguishant even on the live electric wire or cable. Yet a further object of the present invention is to propose an improved fire extinguishant which can advantageously be employed for extinguishing fires such as of the A, B and C class of fires which are not harmful and do not contain any corrosive chlorinated products and still have better thermal characteristics. Still a further object of the present invention is to propose an improved fire extinguishant which can advantageously be employed for extinguishing fires such as of the A, B and C class of fires wherein the decomposition of the extinguishant does not result in the oxides of sulphur. A further object of the present invention is to propose an improved fire extinguishant which can advantageously be employed for extinguishing fires such as of - the A, B and C class of fires wherein the yield, particularly the percent yield and purity of the extinguishant is higher. Another object of the present invention is to propose an improved fire extinguishant which can advantageously be employed for extinguishing fires such as of the A, B and C class of fires which has good anticaking and free flow p roperties. DESCRIPTION OF THE INVENTION: According to this invention there is provided an improved fire extinguishant for extinguishing such as A, B and C class of fires comprising 70 to 80% of a single basic material, 13 to 17% of a filler, 2 to 5% of a dispersing agent and 2 to 5% of a coating agent, and wherein the said fire extinguishant is prepared in the fol1 owing steps: a) heating a single basic material/ filler/ dispersing agent seperately and then mixed and heated in a said reaction vessel followed by cooling and grinding/ and again heating to obtain a reacted mixture, b) said -reacted mixture of step (a) being reacted with a coating agent first at room temperature then at saturated steam temperature with simultaneous solvent recovery, c) the resulted reaction mixture of step (b) being heated and cooled and sieved, d) the sieved reaction mixture from of step (c) being again heated at the temperature higher than that of the temperature of step (a) followed by cool ing. Further according to this invention there is provided a process for the preparation of a fire extinguishant which comprises in:- a) heating a single basic material, filler, dispersing agent seperately and then mixed and heated in a said reaction vessel followed by cooling and grinding and again heating to obtain a reacted mixture, b) said reacted mixture of step (a) being reacted with a coating agent first at room temperature then at saturated steam temperature with simultaneous sovent recovery. c) the resulted reaction mixture of step (b) being heated and cooled and sieved, d) the sieved reaction mixture from of step (c) being again heated at the temperature higher than that of the temperature of step (a) followed by cool ing. In accordance with this invention the improved fire extinguishant, particularly of an improved fire extinguishant formulation, more particular of an improved fire extinguishant formulation for extinguishing the A,B and C class of fires, even more particularly of an improved dry chemical powder fire extinuishant formulation for extinguishing the A,B and C class of fires comprises of single basic material, filler, dispersing agent and coating agent. The single basic material is preferably a phosphate, more preferably it is dibasic phosphate, even more preferably it is monoammonium dihydrogen phosphate. The dispersing agent comprises silica, which essentially is micronised precipitated silica, and is commonly available and cheaper material. The coating agent is preferably silicone oil having viscosity between 70 to 20 CST, preferably between 85 to 105 CST, and taken in the solvent, and the solvent is preferably organic solvent, more preferably is low molecular weight aromatic hydrocarbon and particularly toluene. The filler comprises a mixture of zircon sand powder and of barytes rock powder and both are individualy taken in 6 to 9.5% by weight of the total composition. The total percentage of the mixture of zircon sand powder and of barytes rock powder is maintained between 13 to 17% by weight. According to the preferred embodiment of the process of the presently disclosed invention the single basic material, filler and dispersing agent, as stated above are taken in the said composition, in percent by weight, in the reaction vessel having the arrangements of heating and cooling or in the reaction vessel placed on the heater, and first heated seperately, and then mixed and heated at the temperature of 80 to 100°C for preferably one hour to two hours under forced air circulation and followed by cooling to room temperature and the reasulted rection mixture is again heated at 80 to 100°C for preferably one to two hours essentially after grinding. The moisture contents are essentiaJly maintained at less than 0.5% by weight. According to the preferred embodiment of the process of this invention the grinding, as stated above is preferably done by maintaining the speed of the grounding device at 50 to 60 rpm to obtain particle size of the reaction mixture preferably of less than 120 urn. The grounded reaction mixture is reacted with homogenous solution of coating agent taken in the organic solvent, as stated above, first at room temperature preferably for 30 to 50 minutes and then at saturated steam temperature, preferably at 70 to 110°C. This reaction at saturated steam temperature is carried out under vacuum till complete dryness is obtained and {simultaneously the solvent is recovered. According to the preferred embodiment of the process of this invention the 70 to 125 g of coating agent is taken in 1.0 to 1.7 liters, preferably 1.1 to 1.3 liters of the organic solvent as stated above. The resulted reaction mixture after drying, preferably under vacuum is heated and dried further, preferably at temperature of > 100°C, particularly between the temperature of 120°C to 150°C. The dried reacted mass is cooled and sieved through 125 to 130 jim sieve, and again heated and dried at the same temperature, aa stated above, that is, preferably at temperature of > 10()°C, particularly between the temperature of 120°C to I50°c. The final product, that is, fire extinguishant formulation in accordance to the present invention is obtained on cooling this reacted mass. The yield of the final formulation ir; 'K) to 95%. The solvent recovery is observed 95 to 99%. The fire extinquishant obtainted according the above process, when subjected to physico-chemical characterisation and to the trial had shown the values as shown for each characteristic herein below : Property Analytical Value Bulk density (g/ml) 0.85-1.00 Sieve analysis Passes 100% from um and 90% from 75 um sieves Water repellency > 60 min Hygroscopicity Anticaking (Needle 'penetration test) > 15 mm Low temperature resistance at -80°C for 1 h Passes Heat test at 60°C for 7 days Passes' Thermal resistance •4- 160°C to - 90°C Electric insulation > 5KV Fire test Pasoes Toxicity Self life Non-toxic > 3 years It is clear from the foregoing description and the analytical data, as described above, the fire extinguishant, as disclosed in the present invention is definetely better and has all required characteristics. In addition it has been observed to have better free flowing and fire fighting characteristics, and shelf life. The thermally degraded products were free from any harmful constituent including chlorinated products and were environment freindly. The present invention is described through tho following working example, which is not intended to limit the scope of this invention. Example - 1 1875 g of monoammonium dihydrogen phosphate, 225 g of zircon sand powder mixed with 150 g of barytes rock powder and 125 g of micronised precipated silica, as stated above are taken in the reaction vessel having the arrangements of heating and cooling seperately and are heated at the temperature of 95°C for 1 hour under forced air circulation , and then mixed in one reaction vessel having the similar arrangements of heating and cooling, as stated above, are and heated at the same temperature, that is at the temperature of 95°C for one hour under forced air circulation. The moisture contents of the reaction mixture is maintained less than 0.5% by weight. The reaction mixture after second heating is allowed to cool to room temperature and the reasulted rectiori mixture is again heated at 95°C Cor one hour thirty minutes essentially after grinding at 50 to 60 rpm of the stirrer so as to get the particle size of the reaction mixture preferably of less than 120 um. The grounded reaction mixture? is reacted with homogenous solution of coating agent, which in-turn is prepared by dissolving 125 g of silicons oil of the selected viscosity in 1.5 litres of toluene, first; at room temperature for 35 minutes and then at saturated steam temperature of 100°C. This reaction at saturated steam temperature is carried out under vacuum till complete dryness is obtained and simultaneously the solvent is recovered. The resulted reaction mixture after drying under vacuum is heated and dried further at temperature of > 120°C for two horrs. The dried reacted mass is cooled and sieved through 125 um sieve, and again heated and dried at the temperature of > 120°C for 1 hour. 2375 g of the final product, that is, fire extiriguishant formulation is obtained on cooling this reacted mass. I CLAIM: 1. A process for the preparation of improved fire extinguisher composition for extinguishing A,B and C class of fires comprising of 70 to 80% of a single basic material as herein described, 2 to 5% of dispersing agent as herein described, 2 to 5% of a coating agent as herein described, characterised in that is 13 to 1 70/o of filler, wherein the process steps comprises of: a) heating the said single basic material, filler, dispersing agent separately at a temperature and tLen mixed and heated in a said reaction vessel followed by cooling and grinding, and again heating to obtain a reacted mixture, b) said reacted mixture of step (a) being reacted with said coating agent first at room temperature then at saturated steam temperature as herein described with simultaneous solvent recovery, c) the resulted reaction mixture of step (b) being heated, and cooled and sieved, d) the sieved reaction mixture from of step (c) being again heated at the temperature of 1200 C to 1500 C followed by cooling. 2. A process as claimed in claim 1 wherein the said single basic material is a dibasic phosphate. 3. A process as claimed in claim 2 wherein said phosphate is monoammonium dihydrogen phosphate. 4. A process as claimed in claim 1 wherein said filler is a mixture of zircon sand powder and barytes rock powder. b. A process as claimed in claim 4 wherein the said filler is 6 to 9.5% by weight of the total composition of zircon sand powder and barytes rock powder. 6. A process as claimed in claim 1 wherein said dispersing agent is silica, preferably micronised precipitated silica. 7. A process as claimed in claim 1 wherein said coating agent is silicone present in a solvent, said solvent being an organic solvent for example, a low molecular weight aromatic hydrocarbon, particularly toluene. 8. A process as claimed in claim 1 wherein said heating and cooling of said step (d) is carried out preferably at temperature of > 100CC, particularly between the temperature of 1 200C to 1 500C each time. 9. A process as claimed in preceeding claim 1 wherein the moisture contents is essentially maintained 0.5% by weight. 10. A process as claimed in claim 1 wherein the reaction of the mixture with said homogenous coating solution of said coating agent is first carried out at room temperature for 30 to 50 minutes and then at saturated steam temperature, preferably at 70 to 11 00C preferably under vacuum with simultaneous solvent recovery. 11. A process as claimed in claim 1 wherein 70 to 125 g of said coating agent is taken in 1.0 to 1.7 liters, preferably 1. 1 to 1.3 liters of said organic solvent. 12. A process for the preparation of an improved fire extinguisher composition substantially as herein described and illustrated in the examples.

Documents:

587-del-1997-abstract.pdf

587-DEL-1997-Claims.pdf

587-del-1997-correspondence-others.pdf

587-del-1997-correspondence-po.pdf

587-DEL-1997-Description (Complete).pdf

587-del-1997-form-1.pdf

587-del-1997-form-19.pdf

587-DEL-1997-Form-2.pdf

587-del-1997-form-3.pdf

587-del-1997-gpa.pdf