Patent RU-2731599-C1 (RU)
Title: Method of producing microencapsulated thermo-activated extinguishing agent
Inventor: Skirnevskij Denis Aleksandrovich
IPC: B01J13/02
Filed: 2019-07-17
Granted: 2020-09-04
Abstract: FIELD: fire-fighting equipment. 
     SUBSTANCE: invention relates to means of extinguishing fires in different volumes, specifically to a method of producing a microencapsulated thermoactivated extinguishing agent (hereinafter microcapsules) of a spherical shape of a given diameter and a stabilized activation temperature. Object of this invention is development of new microencapsulated thermoactivated agent in form of monotonous mononuclear microcapsules of spherical shape, specified diameter, thickness of shell, mass and temperature of pulse release of agent, as well as a novel method of producing microcapsules and fire extinguishing articles based thereon. Set task has been solved by developing a method of producing described microencapsulated heat-activated extinguishing agent, which consists in the fact that microcapsules are formed by injection-drop injection under pressure of heated extinguishing agent into the medium of cooled film-forming agent, placed under conditions of low pressure, for this purpose, components are mixed in reactor for preparation of concentrate of film-forming agent, obtained mixture is cooled at low pressure in reactor, then mixed and re-cooled to temperature required for formation of stabilized colloidal condition of film-forming agent concentrate, wherein the extinguishing agent is placed in the tank of the apparatus, the pressure required to remove the air bubbles is created, and with constant stirring, the agent is heated to a certain temperature depending on the preset microcapsule activation temperature, then the heated agent under pressure is supplied to the nozzles unit and the drops are injected into the reactor into the medium of the cooled film-forming concentrate for a certain period of time at the engine shaft rotation speed depending on the preset external diameter of the ready microcapsules, wherein each heated drop, falling in the medium of the film-forming agent concentrate, which is in the reactor at low pressure, expands and forms the primary sphere of the microcapsule nucleus, which becomes the center of activation of the process of hardening (polymerisation) of the film-forming agent, cooling microcapsule nucleus in the low-temperature medium of the reactor is actively compressed, uniformly compacted and creates after hardening a strong microcapsule with a spherical monolithic shell, after the injection cycle, the formed microcapsules are drained, filtered and dried at room temperature. According to the invention, it is desirable that in the reactor the film-forming agent concentrate is cooled to temperature of +10 - +15 °C at pressure of 0.1–0.5 Atm, then mixed and re-cooled to temperature of +8 - +18 °C. According to the invention it is desirable that the agent placed into the tank of the injection plant is heated to a temperature of +35 - +95 °C, then, under pressure of 2.0–4.0 atm, is fed into the medium of the cooled film-forming agent concentrate for not more than 20–30 minutes at the engine shaft rpm of 1500–2500 rpm. Additionally, it is desirable to use as a film-forming agent concentrate a mixture of epoxy resin, diethylene glycol and maleic anhydride, or a mixture of water, gelatine and sodium sulphate, or a mixture of water, polyvinyl alcohol and methanol. Besides, it is desirable to use dibromomethane, or perfluoroketone, or freon 114B2 as a fire extinguishing liquid. According to the invention, the microcapsules have an outer diameter in range of 50–1100 mcm, and the shell weight is 4–10 % of the weight of the microcapsule, and in one batch, not less than 90 % of microcapsules having homogeneous physicochemical indices are obtained. 
     EFFECT: technical result consists in improvement of efficiency of fire extinguishing in various local volumes and is achieved by maintaining physicochemical characteristics of the agent and uniformity of activation parameters by creating a homogeneous monolithic shell of microcapsules with given thickness. 
     12 cl, 3 tbl