AU2019272058B2 - Fire extinguishing agent and fire extinguishing system - Google Patents

Abstract

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Description

FIRE EXTINGUISHING AGENT AND FIRE EXTINGUISHING SYSTEM

The present application claims priority to Chinese patent application No. 201810659753.1, filed on June 22, 2018 with the Chinese patent office, the disclosure of which is incorporated herein in its entirety by reference.

TECHNICAL FIELD

The present application belongs to the technical field of power transformation corollary equipments, for example, relates to a fire extinguishing agent and a fire extinguishing system.

BACKGROUND

A transformer is a power hub of a power energy source internet. A large amount of flammable insulating oil is contained inside a power transformer, and once a fire breaks out, a large-area and long-time power failure accident will occur, thereby causing a great property loss and even casualties. According to statistics, one of every 63 to 81 transformers will break out of fire during its 40-year service period. A total base number of the power transformer is large, and a transformer fire has become a serious disaster threatening safe supply of a power. For example, a transformer at a transformer substation in a province caught fire on June 18, 2016, and multiple transformers were burned down, fault loss loads were 243,000 kilowatts, the number of power failure users was 86,500 households, and the social influence was enormous. Therefore, there is an urgent need to develop an efficient fire extinguishing technology for transformer oil fire.

The addition of a water-based fire extinguishing agent to water can significantly improve the fire extinguishing effect of the water. However, fire extinguishing agents on the market are mainly for conventional fires, such as Class A fires of woods and plastics, as well as Class B fires of gasoline and diesel and the like. Transformer oil is a heavy oil with high viscosity and high calorific value, so its fire extinguishing principle is different from those of oil fires such as gasoline and diesel and the like. Therefore, traditional oil-based fire extinguishing fluids are difficult to apply to the suppression of a transformer oil fire. Moreover, for the traditional fire extinguishing fluids, an insulation problem is not considered, and the traditional fire extinguishing fluids adopt a large amount of conductive ionic compounds and cannot be applied to a charged environment. Therefore, there is an urgent need to develop a fire extinguishing fluid for transformer oil with strong insulation performance and high fire extinguishing efficiency.

Any discussion of documents, acts, materials, devices, articles or the like which has been included in the present specification is not to be taken as an admission that any or all of these matters form part of the prior art base or were common general knowledge in the field relevant to the present disclosure as it existed before the priority date of each of the appended claims.

Throughout this specification the word "comprise", or variations such as "comprises" or "comprising", will be understood to imply the inclusion of a stated element, integer or step, or group of elements, integers or steps, but not the exclusion of any other element, integer or step, or group of elements, integers or steps.

SUMMARY

The technical problem to be solved by the present application is to overcome the deficiencies and defects mentioned in the above background art, to provide a fire extinguishing agent with strong insulation performance and high fire extinguishing efficiency, and to provide a fire extinguishing system accordingly.

A technical solution proposed by the present application is as follows:

A fire extinguishing agent comprises, in parts by weight, components of:

20-30 parts of an oil-in-water emulsifier;

5-20 parts of a cloud point improver;

3-15 parts of a surface spreading agent;

1-5 parts of a combustion negative catalyst;

1-5 parts of a near-fire gelling synergist;

0.1-3 parts of a corrosion inhibitor; and

40-60 parts of water.

Transformer oil has higher viscosity, and its fire extinguishing principle is different from those of oil fires such as gasoline, diesel and the like. Traditional oil-based fire extinguishing fluids are difficult to apply to the suppression of a transformer oil fire. Researchers have found that the transformer oil is emulsified by the oil-in-water emulsifier to form an oil-in-water type specific emulsion, such that the flammability of fuel oil can be remarkably reduced, and efficient fire extinguishing can be achieved.

In an embodiment, in the above-mentioned fire extinguishing agent, the oil-in-water emulsifier is one selected from the group consisting of: polyoxyethylene oxypropylene oleate, polyoxyethylene sorbitol beeswax derivative, tetraethylene glycol monolaurate, polyoxyethylene lauryl ether, polyoxyethylene sorbitan monostearate, hexaethylene glycol monostearate, polyoxyethylene sorbitan monooleate, polyethylene glycol laurate, polyoxyethylene cetyl ether, polyoxyethylene sorbitan tristearate, polyoxyethylene sorbitan trioleate, polyoxyethylene lanolin derivative, polyoxyethylene monooleate, polyoxyethylene monopalmitate, alkylaryl sulfonate, triethanolamine oleate, polyoxyethylene monolaurate, polyoxyethylene alkylphenol, polyoxyethylene sorbitol lanolin derivative, polyoxyethylene alkyl aryl ether, polyoxyethylene monolaurate, polyoxyethylene lauryl ether, polyoxyethylene castor oil, polyoxyethylene vegetable oil, polyoxyethylene sorbitan monolaurate, polyoxyethylene esters of mixed fatty acids and resin acids, polyoxyethylene sorbitan monostearate, polyoxyethylene oleyl ether, polyoxyethylene stearyl alcohol, polyoxyethylene oleyl alcohol, polyoxyethylene fatty alcohol, polyethylene glycol monopalmitate, polyoxyethylene sorbitan monopalmitate, polyoxyethylene cetyl alcohol, polyoxyethylene oxypropylene stearate, polyoxyethylene sorbitol lanolin derivative, polyoxyethylene monostearate, and a combination of more selected therefrom.

In an embodiment, in the above-mentioned fire extinguishing agent, the cloud point improver is one or more selected from the group consisting of: fatty acid methyl ester ethoxylate, alkyl polyglycoside, and N-alkyl glucose amide. Under the influence of the molecular structure and the coexisting substance(s) of a surfactant, the emulsifier solution will appear turbid as the temperature increases, which will affect the performances of the emulsifier. The temperature at the transition of the emulsifier solution is a cloud point temperature. Since the fire extinguishing fluid needs to be placed at room temperature, if the cloud point temperature is too low, it will affect the use of the fire extinguishing agent. The cloud point temperature of the fire-extinguishing agent can be greatly improved by adding the fatty acid methyl ester ethoxylate, the alkyl polyglycoside and the N-alkyl glucose amide.

In an embodiment, in the above-mentioned fire extinguishing agent, the surface spreading agent is one or more selected from the group consisting of: fluorocarbon nonionic surfactants, and silicone-polyether copolymers. The type of the fluorocarbon nonionic surfactant includes XW-201 (a perfluorinated polyoxyethylene ether produced by Dongying Xinwang Chemical Co., Ltd.), XW-101 (a perfluorinated polyoxyethylene ether produced by Dongying Xinwang Chemical Co., Ltd.), FC-4430 (a fluorinated aliphatic polymer grease with a perfluorobutyl fluorocarbon surfactant, produced by the 3M company, containing 90% polymeric fluorochemical actives, 8% non-fluorochemical actives, and 2% of a co-solvent), FC-430 (a perfluoroalkyl ester, with the CAS number: 11114-17-3 and produced by the Morinaga Chemical Co., Ltd., Japan), RK-8317 (a perfluoroalkyl polyether produced by Shandong Yunqingxin Technology Development Co., Ltd.), FC-2 (a perfluoroalkyl betaine produced by Shanghai Yingzheng Technology Co., Ltd.) and RK-8316 (a perfluoroalkyl phosphate produced by Shandong Yunqingxin Technology Development Co., Ltd.), and the type of the silicone-polyether copolymer includes SPE (a polyether modified silicone oil produced by Dow Corning), DY-ET121L (a polyether modified silicone oil produced by Shandong Dayi Chemical Co., Ltd.), SH-300 (a polyether modified silicone produced by Hubei New Sihai Co., Ltd.), 600CS (a dimethicone with a viscosity of 600 cs) and 1000CS (a dimethicone with a viscosity of 1000cs). During the fire extinguishing process, whether the fire extinguishing agent can be quickly spread on the surface of the fuel oil is the key for ensuring the fire extinguishing effect of the fire extinguishing agent and preventing the re-ignition of the transformer oil. The spreading speed of the fire extinguishing agent on the surface of the transformer oil can be obviously improved by adopting the above-mentioned surface spreading agent, thus the ability of the fire extinguishing agent for preventing the re-ignition of the transformer oil is finally improved.

3A

In an embodiment, in the above-mentioned fire extinguishing agent, the combustion negative catalyst is one or more selected from the group consisting of: 4,4'-bis(a,a-dimethylbenzyl)diphenylamine, thiourea, methionine, cysteine hydrochloride, and catechol. The combustion process of organic compounds is a series of radical reactions. Under the action of heat, light or oxygen, the chemical bonds of organic molecules are broken to generate active radicals and hydroperoxide, and the hydroperoxide is decomposed to generate alkoxyl radicals and hydroxyl radicals. These radicals can initiate a series of radical reactions that result in a combustion change in the structure and properties of organic compounds. The combustion negative catalyst is a substance that can slow or inhibit chemical reaction processes, the action of which is contrary to that of a conventional catalyst. The conventional catalyst is a substance that can accelerate chemical reaction processes. The action of the combustion negative catalyst is to eliminate the radicals that have just been produced or to promote the decomposition of the hydroperoxide, thereby preventing combustion. The specific combustion negative catalyst described above has a combustion negative catalytic effect on the transformer oil fire.

In an embodiment, in the above-mentioned fire extinguishing agent, the near-fire gelling synergist is one or more selected from the group consisting of: hydroxyethyl cellulose, hydroxypropyl cellulose, and hydroxypropyl carboxymethyl cellulose. A water mist fire extinguishing process has a problem that: since mist droplet particles are relatively small (less than 400 microns (pm)), when the fire is very great, the mist droplet particles are substantially vaporized without being near a fire source, so the bestfire extinguishing effect cannot be achieved. How to control the evaporation speed of the fire extinguishing agent in mist droplets is a key issue to achieve an efficient fire extinguishing. Researches have found that hydroxyethyl cellulose, hydroxypropyl cellulose, and hydroxypropyl carboxymethyl cellulose may undergo high temperature gelling at temperatures up to about 80 celsius degree (°C) to form semi-solid gel. Therefore, based on the above researches, the present invention adds one or more of hydroxyethyl cellulose, hydroxypropyl cellulose, and hydroxypropyl carboxymethyl cellulose to the fire extinguishing agent. When the mist droplets of the fire extinguishing agent are close to the fire source, since the mist droplet is heated, the mist droplet particles will generate gelation, such that the evaporation rate of water will be reduced, and mist droplets may be allowed to get closer to the fire source and then to be evaporated or produce fire extinguishing effect, thereby significantly improving the fire extinguishing performance of the fire extinguishing fluid.

In an embodiment, in the above-mentioned fire extinguishing agent, the corrosion inhibitor is one or more selected from the group consisting of: mercaptobenzothiazole, sulfonated lignin, methylbenzotriazole, benzotriazole, mercaptobenzothiazole, tallow amine, hexadecylamine, octadecylamine, hydroxyethylidene diphosphonic acid, disodium hydroxyethylidene diphosphonic acid, polyacrylic acid, polyaspartic acid, and polyethyleneimine. The corrosion inhibitor can be divided into three types. The first type of the corrosion inhibitor is an adsorption film-type corrosion inhibitor with polar groups that may be adsorbed by the charge on metal surface to form a lay of monomolecular film throughout an anode region and a cathode region, thereby preventing or slowing the occurrence of electrochemical reactions. Such corrosion inhibitor includes tallow amine, hexadecylamine and octadecylamine. The second type of the corrosion inhibitor contains both hydrophilic groups and hydrophobic groups, and is nitrogen-containing, sulfur-containing or hydroxyl-containing surface-active organic compounds. The molecules of these compounds are adsorbed on the metal surface by hydrophilic groups to form a lay of dense hydrophobic film that protects the metal surface from water corrosion. Such corrosion inhibitor includes hydroxyethylidene diphosphonic acid, disodium hydroxyethylidene diphosphonate, polyacrylic acid, polyaspartic acid, and polyethyleneimine. The third type of the corrosion inhibitor can form complexes with metal, and then form a film on the surface. Such corrosion inhibitor includes mercaptobenzothiazole, benzotriazole, sulfonated lignin, methylbenzotriazole, benzotriazole, mercaptobenzothiazole and is a corrosion inhibitor for non-ferrous metals, especially copper. In order to reduce the corrosion of the fire extinguishing agent on equipments, the present application adopts a combination of multiple corrosion inhibitors in the fire extinguishing agent, such that the effects of various types of corrosion inhibitors may be superimposed on each other to achieve the best corrosion inhibition effect.

As a general technical concept, the present application also provides a fire extinguishing system, comprising a water storage tank , a fire extinguishing agent mixing device, afire extinguishing agent tank, a pump set pressure module configured to pump water in the water storage tank into the fire extinguishing agent mixing device, a partition control system configured to distribute a fire extinguishing agent in the fire extinguishing agent mixing device to multiple transformers, a sprinkler system configured to be disposed around the transformers (including multiple nozzles surrounding the transformers), and an automatic control-protection device configured to control the pump set pressure module to be started and shut down and to automatically protect the stability of the system, wherein the automatic control-protection device is connected to the pump set pressure module, the water storage tank is connected to an inlet of the pump set pressure module, an outlet of the pump set pressure module is connected to an inlet of the fire extinguishing agent mixing device, the fire extinguishing agent tank is also connected to the inlet of the fire extinguishing agent mixing device, and an outlet of the fire extinguishing agent mixing device is connected to an inlet of the partition control system, an outlet of the partition control system is in communication with the sprinkler system.

In an embodiment, in the above-mentioned fire extinguishing system, the fire extinguishing agent stored in the fire extinguishing agent tank is the above-mentioned fire extinguishing agent. Generally, the viscosity of the pure components of the fire extinguishing agent in the present application is large, and the concentration of the fire extinguishing agent actually used for fire extinguishing is less than 0.5%. The fire extinguishing agent in the present application is placed in the fire extinguishing agent tank, and a certain proportion of water needs to be added. The water in the water storage tank is, in the extinguishing agent mixing device, mixed with the fire extinguishing agent in the fire extinguishing agent tank via the pump set pressure module and then the mixture enters into the subsequent system to achieve the dilution of the fire extinguishing agent.

In the above-mentioned fire extinguishing system, the presence of the partition control system enables the above-mentioned fire extinguishing system to simultaneously serve multiple transformers. The partition control system is a set of valve banks, i.e., commonly used electric ball valves, and different transformers correspond to different electric ball valves. Provided that a set of fire-extinguishing system protects three transformers, and since the transformers are independent of each other, generally three transformers will not be ignited at the same time in a case where a fire occurs, usually one transformer is ignited. Partition control may be implemented for different transformers through the partition control system. When a certain type of transformer is ignited, it is only necessary to open the electric ball valve of this zone to extinguish the fire, thereby enabling a set of fire extinguishing device to cover multiple transformers.

In the above-mentioned fire extinguishing system, the presence of the automatic control-protection device protects the entire fire extinguishing system. If a water pressure in the pump set pressure module is too high, the pump set pressure module will be automatically shut down to protect the system; if there is no water in the water storage tank, the pump set pressure module will be automatically shut down to protect the pump set and the like.

In an embodiment, in the above-mentioned fire extinguishing system, the mist droplets of the water mist sprayed by the sprinkler system have a diameter of 200 m-400 m, a concentration of 20 g/(m2 -s)-100 g/(m 2 -s), and an average initial axial spraying speed of 6 m/s-20 m/s. The water mist having the above-mentioned physical properties has an insulation performance comparable to or better than the air.

In the above-mentioned fire extinguishing system, the mist droplet diameter and the mist droplet concentration of the water mist sprayed by the sprinkler system are obtained by performing relevant tests using the device shown in Figure 1.

The test device shown in Figure 1 comprises a power supply module, a water mist sprinkler, a measuring system for mist droplet diameter, an analog transformer bushing, and a conductivity measuring module. The power supply module can generate high voltage electricity, the measuring system for mist droplet diameter measures the mist droplet diameter of the water mist, the analog transformer bushing analogs a discharge body, and the conductivity measuring module measures the conductivity value of the water. At the beginning of the test, firstly, the conductivity of the water added to the fire extinguishing agent is measured, and then a charged breakdown test of water mist is carried out. The breakdown voltage test procedure of the test refers to the measuring method in artificial pollution tests on high-voltage insulators (GB/T 4584-2004/IEC 60507:1991), and the water mist breakdown voltage value is measured by a method of 50% withstand voltage. The discharge interval adopted by the charged breakdown test of water mist is 3 meters (m), and a breakdown voltage characteristic rule of water mist !0 under this working condition is obtained. Accordingly, parameter sections of the diameter and the concentration of the mist droplets suitable for charged fire extinguishment are obtained in the rule.

In the above-mentioned fire extinguishing system, the water mist is applied outdoors, and it is necessary to satisfy a certain windproof requirement. The wind resistance ability of the water mist can be studied by using the device shown in Figure 2. The test device shown in Figure 2 comprises a water pump, a water mist sprinkler, a mist droplet three-dimensional speed measuring system, and a wind tunnel. At the beginning of the test, the water pump is started and water mist is sprayed, and the speed of the mist droplets in a three-dimensional range is measured. Then, the wind tunnel is opened, the wind speed is controlled, and the changes in the o distance of the water mist sprinkler and the atomizing cone angle are observed. Researches have found that among various mist droplet physical properties and mist droplet three-dimensional speed parameters, the diameter and average initial axial spraying speed of the mist droplets determine the changes of the water mist spraying distance and the atomization cone angle. Therefore, it may be considered that the two parameters are the key factors influencing the wind resistance performance of the water mist. In the present application, test studies on the average initial axial spraying speed and wind resistance performance of different mist droplets are carried out in the range of 200 micron-400 micron of mist droplets , and researches have found that the average initial axial spraying speed of the mist droplet capable of resisting 5-level wind is 6 m/s-12 m/s.

In the above-mentioned fire extinguishing system, since the above-mentioned fire extinguishing agent with strong insulation performance (due to the use of a non-ionic substance) is adopted, and relevant parameters of the sprinkler system are controlled, such that the fire extinguishing system with high insulation performance and high fire extinguishing efficiency is finally obtained.

The fire extinguishing agent provided by the present application comprises a nonionic oil-in-water emulsifier, a cloud point improver, a surface spreading agent, a combustion negative catalyst, a near-fire gelling synergist, a corrosion inhibitor and water. The nonionic oil-in-water emulsifier reduces the flammability of fuel oil; the combustion negative catalyst achieves flame retardancy, prevents oil fire from being combusted, and rapidly extinguishes flame; the surface spreading agent prevents the re-ignition of the oil fire; the near-fire gelling synergist further improves the utilization rate of fire extinguishing components of the fire !0 extinguishing agent; and the cloud point improver and the corrosion inhibitor ensure the fire extinguishing effectiveness and the application range of the fire extinguishing agent. The above-mentioned various substances have weak electrical conductivity and strong insulation performance, and various substances collaborate with each other, such that the finally obtained composite fire extinguishing agent has the advantages of high insulation performance, high fire !5 extinguishing efficiency, and safe and reliable in electrification.

BRIEF DESCRIPTION OF DRAWINGS

Figure 1 is a schematic view of a water mist atomization insulation test device;

Figure 2 is a schematic view of a water mist wind resistance test device; and

Figure 3 is a schematic structural view of a fire extinguishing system in an embodiment.

Illustrations:

1. automatic control-protection device; 2. pump set pressure module; 3. water storage tank; 4. fire extinguishing agent mixing device; 5. fire extinguishing agent tank; 6. partition control system; 7. sprinkler system.

DETAILED DESCRIPTION

In order to facilitate the understanding of the present application, the present application will be described more fully and in detail below in conjunction with the drawings and examples, but the protection scope of the present application is not limited to the following specific examples.

Unless otherwise defined, all technical terms used hereinafter have the same meaning as commonly understood by those skilled in the art. The technical terms used herein are for the purpose of describing specific examples only and are not intended to limit the protection scope of the present application.

Unless otherwise specifically stated, various raw materials, reagents, instruments, equipments and the like used in the present application are commercially available or may be prepared by using existing methods.

Example 1:

A fire extinguishing agent for transformer oil comprises components of: 5 kilograms (kg) of polyethylene glycol laurate, 2 kg of N-alkyl glucose amide, 2 kg of a fluorocarbon surfactant (FC-4430), 1.0 kg of catechol, 300 g of hydroxypropyl cellulose, 50 grams (g) of mercaptobenzothiazole, 50 g of polyethyleneimine, and 15 kg of water. The preparation method of the fire extinguishing agent comprises steps of: firstly, 5kg of polyethylene glycol laurate, 2kg of N-alkyl glucose amide and 10kg of water are uniformly stirred in a 10 L glass stirred reaction kettle for 1 hour to obtain a mixture A; then, the mixture A is mixed with 2 kg of FC-4430, 1.5 kg of catechol, 300 g of hydroxypropyl cellulose, 50 g of mercaptobenzothiazole, !5 50 g of polyethyleneimine and 5 kg of water and meanwhile stirred for 1 hour to obtain a sample 1.

Comparative Example 1:

The fire extinguishing agent for transformer oil of this comparative example is different from that of Example 1 in that polyethylene glycol laurate is not added in this comparative example, and a sample 2 is obtained in this comparative example.

Comparative Example 2:

The fire extinguishing agent for transformer oil of this comparative example is different from that of Example 1 in that N-alkyl glucose amide is not added in this comparative example, and a sample 3 is obtained in this comparative example.

Comparative Example 3:

The fire extinguishing agent for transformer oil of this comparative example is different from that of Example 1 in that FC-4430 is not added in this comparative example, and a sample 4 is obtained in this comparative example.

Comparative Example 4:

The fire extinguishing agent for transformer oil of this comparative example is different from that of Example 1 in that catechol is not added in this comparative example, and a sample 5 is obtained in this comparative example.

Comparative Example 5:

The fire extinguishing agent for transformer oil of this comparative example is different from that of Example 1 in that hydroxypropyl cellulose is not added in this comparative example, and a sample 6 is obtained in this comparative example.

Application Example 1:

Firstly, an oil pan with a diameter of 100 centimeters (cm) is placed on a horizontal ground, 20 L of water is added to the oil pan (the water is used for cooling down and preventing the oil pan from being combusted), then 10 L of 25# karamay transformer oil is added, and finally 500 mL of gasoline is added for ignition. The fire is extinguished by using pure water and water with samples 1-6 added, and by using a high pressure water mist pump set and a sprinkler, where the pump set pressure is 12 megapascals (MPa) and the flow rate is 750 milliliter/minute (ml/min). A fire plate is ignited, firstly, a pre-combustion for 360 seconds (s) is carried out, then a water pump set is started, and a water pump pressure is increased, fire extinguishing is implemented; after an open flame is extinguished, the fire extinguishing agent is stopped to be sprayed and the fire extinguishing time is recorded. In order to ensure repeatability, each set of tests is performed at least twice and then the fire extinguishing times are averaged. The comparison of the effective fire extinguishing times of the above seven fire extinguishing agents is shown in table 1 below.

Table 1: the effective fire extinguishing times of the seven fire extinguishing agents in Application Example 1

Sample Pure Sample 1 Sample 2 Sample 3 Sample 4 Sample 5 Sample 6 water

Fire 100 25 46 28 30 68 72 extinguishing time (s) As can be seen from the table 1, the fire extinguishing effect of the sample 1 is the best, and the oil-in-water emulsifier, the combustion negative catalyst, and the near-fire gelling synergist are o three key components that determine the fire extinguishing performance of the fire extinguishing agent.

Application Example 2:

According to provisions in chapter 5.10.5.2 of National Standard GB15308-2005 "Foam Extinguishing Agent", a fire resistance test of the fire extinguishing agent is carried out. The time that 25% of a fuel area is ignited, that is 25% anti-combusting time, is recorded. The comparison of the 25% anti-combusting times of the above seven fire extinguishing agents is shown in table 2 below.

Table 2: the effective anti-combusting times of the seven fire extinguishing agents in Application Example 2

Sample Pure water Sample 1 Sample 2 Sample 3 Sample 4 Sample 5 Sample 6

Fire 3 7 7 7 3 8 7 extinguishing time (min)

As can be seen from the table 2, the surface spreading agent is a key component in determining the ability of the fire extinguishing agent to prevent re-ignition.

Application Example 3:

An electrified insulation test is set in accordance with the requirements specified in Article 7.13 of the National Standard GB4351.1-2005 "portable fire extinguisher Part 1: PERFORMANCE AND STRUCTURAL REQUIREMENTS". A metal plate of (10.025) m x (1+0.025) m is suspended perpendicularly on an insulating bracket, and the metal plate is connected to a transformer to establish a (36+3.6) kilovolt (kV) AC voltage between the metal plate and the earth. The impedance of this loop should be: when a voltage equal to 10% of the normal primary is applied to a primary circuit and a secondary circuit is shorted, a secondary current is not less than 0.1 milliamps (mA). Then, the fire extinguisher is fixed on the insulating bracket such that: the nozzle is kept Im from the center of the metal plate, and the nozzle is aligned with the center of the metal plate in a manner of being at right angles relative to the metal plate. The fire extinguisher is connected to the earth. For the fire extinguisher equipped with a spraying hose, the nozzle should be connected to a handle, and then connected to the earth. The metal plate is energized, the fire extinguisher is opened to spray, and the current flowing between the fire extinguisher and the earth is measured until the spraying is finished. The comparison of the effective fire extinguishing times of the above seven fire extinguishing agents is shown in table 3 below.

Table 3: the currents flowing between the fire extinguishing agent and the earth when the seven fire extinguishing agents are performed to extinguish fire in Application Example 3

Sample Pure Sample 1 Sample 2 Sample 3 Sample 4 Sample 5 Sample 6 water

Current 0.22 0.21 0.21 0.22 0.21 0.22 0.21 value (mA)

As can be seen from the table 3, since a nonionic compound component is adopted in this example, the fire extinguishing agent has good charging safety performance.

Application Example 4

15-20 ml of a fire extinguishing agent is weighed into a test tube, and is heated in water bath until the fire extinguishing agent becomes turbid. The fire extinguishing agent is stirred and meanwhile cooled by using a thermometer, and a re-clarified temperature point is determined, wherein the re-clarified temperature is a cloud point of the fire extinguishing agent. The cloud points of the above seven fire extinguishing agents are shown in table 4 below.

Table 4: the cloud points of the seven fire extinguishing agents in Application Example 4

Sample Pure Sample 1 Sample 2 Sample 3 Sample 4 Sample 5 Sample 6 water

Cloud 56 34 65 55 56 58 59 point (°C)

As can be seen from the table 4, the addition of the cloud point improver can significantly increase the cloud point of the fire extinguishing agent, and can maintain long-term stability at about 60 degrees, and can be used in various weather conditions.

Application Example 5:

Researches have found that a large air gap generated between the fine mist droplets of the water mist can improve the insulation performance of water, therefore the charged safety performance is relatively high. However, in terms of a transformer fire extinguishing systems for outdoor application, due to the influence of wind in the outdoor, it is also necessary to satisfy the wind resistance requirements in addition to satisfy the charged safety performance.

As shown in Figure 3, afire extinguishing system comprises a pump set pressure module 2, a water storage tank 3, a fire extinguishing agent mixing device 4, a fire extinguishing agent tank 5, a partition control system 6, a sprinkler system 7 configured to be disposed around the transformers (including multiple nozzles surrounding the transformers) and an automatic control-protection device 1 configured to control the pump set pressure module 2 to be started and shut down and to automatically protect the stability of the system. The automatic control-protection device 1 is connected to the pump set pressure module 2, the water storage tank 3 is connected to an inlet of the pump set pressure module 2, an outlet of the pump set pressure module 2 is connected to an inlet of the fire extinguishing agent mixing device 4, and the fire extinguishing agent tank 5 is also connected to the inlet of the fire extinguishing agent mixing device 4, an outlet of the fire extinguishing agent mixing device 4 is connected to an inlet of the partition control system 6, and an outlet of the partition control system 6 is in communication with the sprinkler system 7. In this application example, the fire extinguishing agent prepared in Example 1 is stored in the fire extinguishing agent tank 5, and the mist droplets of the water mist sprayed by the sprinkler system is controlled to have a diameter of 200 m-400 jm, a concentration of 20 g/(m 2 -s)-100 g/(m 2-s), and an average initial axial spraying speed of 6 m/s-20 m/s.

In this application example, the mist droplet diameter and the mist droplet concentration of the water mist sprayed by the sprinkler system are obtained by performing relevant tests using the device shown in Figure 1, and the wind resistance ability of the water mist can be studied by using the device shown in Figure 2. The test device shown in Figure 1 comprises a power source module, a water mist sprinkler, a measuring system for mist droplet diameter, an analog transformer bushing, and a conductivity measuring module. The power supply module can generate high voltage electricity, the measuring system for mist droplet diameter measures the mist droplet diameter of the water mist, the analog transformer bushing analogs a discharge body, and the conductivity measuring module measures the conductivity value of the water. At the beginning of the test, firstly, the conductivity of the water added to the fire extinguishing agent is measured, and then a charged breakdown test of water mist is carried out. The breakdown voltage test procedure of the test refers to the measuring method in artificial pollution tests on high-voltage insulators (GB/T 4584-2004/IEC 60507:1991), and the water mist breakdown voltage value is measured by a method of 50% withstand voltage. The discharge interval adopted by the charged breakdown test of water mist is 3m, and a breakdown voltage characteristic rule of water mist under this working condition is obtained. Accordingly, parameter sections of the diameter and the concentration of the mist droplets suitable for charged fire extinguishment are obtained in the rule.

The test device shown in Figure 2 comprises a water pump, a water mist sprinkler, a mist droplet three-dimensional speed measuring system, and a wind tunnel. At the beginning of the test, the water pump is started and water mist is sprayed, and the speed of the mist droplets in a three-dimensional range is measured. Then, the wind tunnel is opened, the wind speed is controlled, and the changes in the distance of the water mist sprinkler and the atomizing cone angle are observed.

The fire extinguishing system in the application example achieves the application of the emulsified, insulating and charged fire extinguishing agent for the transformer, and is suitable for wide popularization and application. In addition, the fire extinguishing system in the application example is not only suitable for the prevention and control of multiple voltage levels of transformer fires, but also can be widely applied to the prevention and control of fires of various types of oil insulated equipment and cable tunnel fires, and can be popularized to the protection of the fire in an ultra-high voltage valve hall, and the application potential is huge.

The water mist sprayed by the fire extinguishing system provided by the present application has strong insulation performance, can achieve charged fire extinguishment, and has outdoor wind resistance ability.

The fire extinguishing system provided by the present application has a simple structure, is easy to handle, and has a wide application range.

Claims (9)

What is claimed is:

1. A fire extinguishing agent comprising, in parts by weight, components of:

20-30 parts of an oil-in-water emulsifier;

5-20 parts of a cloud point improver;

3-15 parts of a surface spreading agent;

1-5 parts of a combustion negative catalyst;

1-5 parts of a near-fire gelling synergist;

0.1-3 parts of a corrosion inhibitor; and

40-60 parts of water.

2. The fire extinguishing agent of claim 1, wherein the oil-in-water emulsifier is at least one selected from the group consisting of: polyoxyethylene oxypropylene oleate, polyoxyethylene sorbitol beeswax derivative, tetraethylene glycol monolaurate, polyoxyethylene lauryl ether, polyoxyethylene sorbitan monostearate, hexaethylene glycol monostearate, polyoxyethylene sorbitan monooleate, polyethylene glycol laurate, polyoxyethylene cetyl ether, polyoxyethylene sorbitan tristearate, polyoxyethylene sorbitan trioleate, polyoxyethylene lanolin derivative, polyoxyethylene monooleate, polyoxyethylene monopalmitate, alkylaryl sulfonate, triethanolamine oleate, polyoxyethylene monolaurate, polyoxyethylene alkylphenol, polyoxyethylene sorbitol lanolin derivative, polyoxyethylene alkyl aryl ether, polyoxyethylene monolaurate, polyoxyethylene lauryl ether, polyoxyethylene castor oil, polyoxyethylene vegetable oil, polyoxyethylene sorbitan monolaurate, polyoxyethylene esters of mixed fatty acids and resin acids, polyoxyethylene sorbitan monostearate, polyoxyethylene oleyl ether, polyoxyethylene stearyl alcohol, polyoxyethylene oleyl alcohol, polyoxyethylene fatty alcohol, polyethylene glycol monopalmitate, polyoxyethylene sorbitan monopalmitate, polyoxyethylene cetyl alcohol, polyoxyethylene oxypropylene stearate, polyoxyethylene sorbitol lanolin derivative, and polyoxyethylene monostearate.

3. The fire extinguishing agent of claim 1 or claim 2, wherein the cloud point improver is at least one selected from the group consisting of: fatty acid methyl ester ethoxylate, alkyl polyglycoside, and N-alkyl glucose amide.

4. The fire extinguishing agent of any one of claims 1 to 3, wherein the surface spreading agent is at least one selected from the group consisting of: fluorocarbon nonionic surfactants, and silicone-polyether copolymers, wherein the fluorocarbon nonionic surfactant optionally comprises: a perfluorinated polyoxyethylene ether, a fluorinated aliphatic polymer grease, a perfluoroalkyl ester with CAS number: 11114-17-3, a perfluoroalkyl polyether, a perfluoroalkyl betaine, or a perfluoroalkyl phosphate, and the type of the silicone-polyether copolymer optionally comprises: a polyether modified silicone oil, a dimethicone with a viscosity of 600 cs or a dimethicone with a viscosity of 1000 Cs.

5. The fire extinguishing agent of any one of claims 1 to 4, wherein the combustion negative catalyst is at least one selected from the group consisting of: 4,4'-bis(a,a-dimethylbenzyl)diphenylamine, thiourea, methionine, cysteine hydrochloride, and catechol.

6. The fire extinguishing agent of any one of claims 1 to 5, wherein the near-fire gelling synergist is at least one selected from the group consisting of: hydroxyethyl cellulose, hydroxypropyl cellulose, and hydroxypropyl carboxymethyl cellulose.

7. The fire extinguishing agent of any one of claims 1 to 6, wherein the corrosion inhibitor is at least one selected from the group consisting of: mercaptobenzothiazole, sulfonated lignin, methylbenzotriazole, benzotriazole, mercaptobenzothiazole, tallow amine, hexadecylamine, octadecylamine, hydroxyethylidene diphosphonic acid, disodium hydroxyethylidene diphosphonic acid, polyacrylic acid, polyaspartic acid, and polyethyleneimine.

8. A fire extinguishing system comprising: a water storage tank, a fire extinguishing agent mixing device, a fire extinguishing agent tank, a pump set pressure module configured to pump water in the water storage tank into the fire extinguishing agent mixing device, a partition control system configured to distribute a fire extinguishing agent in the fire extinguishing agent mixing device to multiple transformers, a sprinkler system configured to be disposed around the transformers, and an automatic control-protection device configured to control the pump set pressure module to be started and shut down and to automatically protect the stability of the system, wherein the automatic control-protection device is connected to the pump set pressure module, the water storage tank is connected to an inlet of the pump set pressure module, an outlet of the pump set pressure module is connected to an inlet of the fire extinguishing agent mixing device, the fire extinguishing agent tank is connected to the inlet of the fire extinguishing agent mixing device, and an outlet of the fire extinguishing agent mixing device is connected to an inlet of the partition control system, an outlet of the partition control system is in communication with the sprinkler system; wherein the fire extinguishing agent stored in the fire extinguishing agent tank is the fire extinguishing agent of any one of claims 1 to 7.

9. The fire extinguishing system of claim 8, wherein the fire extinguishing system is used for a transformer, wherein the mist droplets of the water mist sprayed by the sprinkler system have a diameter of 200 m-400 jm, a concentration of 20 g/(m 2 -s)-100 g/(m 2 -s), and an average initial axial spraying speed of 6 m/s-20 m/s.