WO2024172692A1 - Aerosol flooding fire-extinguishing device - Google Patents

Abstract

The invention relates to an aerosol flooding fire-extinguishing device for suppressing a fire at source through the action of an aerosol medium that is formed upon combustion of a solid charge of an aerosol-forming composition. The device comprises a housing having a bottom and a nozzled cap, an aerosol-forming charge in the form of a non-perforated pellet, a protective anchoring layer, an auxiliary combustion chamber formed inside the housing, a triggering assembly mounted in the cap, and an ejection head connected to the housing. Formed in the centre part of the end surface of the charge facing the bottom of the housing is a cavity that is filled with a fire-extinguishing agent. The nozzled cap is provided with nozzles that have a critical cross-section and is further provided with a heat shield that extends into the housing. The nozzles are configured such as to pass through the cap with the heat shield and to extend from the outer surface of the cap. The device contains an anti-adhesive separation layer which is applied to the inner surface of the lateral wall of the housing and is situated between the protective anchoring layer and said surface, wherein the protective anchoring layer is configured such that the outer lateral surface of the heat shield of the cap is in contact therewith.

Description

DEVICE FOR VOLUMETRIC AEROSOL FIRE EXTINGUISHING

Field of technology

The invention relates to fire-fighting equipment, namely to devices for volumetric aerosol fire extinguishing, which ensure suppression of a fire by exposing the source to an aerosol environment formed during the combustion of a solid charge of an aerosol-forming composition (AFC).

Prior art

A device for extinguishing fires is known (patent RU 2116090 C1, published 27.07.1998), which contains a heat-protected housing, an initiation means and an axially sequentially located pyrotechnic charge, a combustion chamber, a cooling cylinder inside the combustion chamber filled with a gas-permeable ablative layer and closed with a cover in the form of a truncated cone with outlet openings distributed on its side surface for forming a jet flow of aerosol.

The disadvantage of the known device is that when passing through the coolant layer, some of the active condensed aerosol particles settle on the surface of the coolant layer and, accordingly, do not enter the protected volume, which leads to a decrease in the fire extinguishing capacity of the generator.

A fire extinguishing device with a highly effective fire extinguishing aerosol is also known (CN 107519602 A, 29.12.2017), which includes: a shell divided into upper and lower parts, a heat-insulating insert, a launch unit, an aerosol-forming charge, a block with a composite material containing ceramic fiber and a cooling agent, a mesh screen, an insert with channels for jets, sealing films, one of which is glued to the insert, and the other is glued to the lower top cover surface, block with cooling ultrafine powder, and top cover with Laval nozzles.

The known device has the same significant drawback as the device according to patent RU 2116090 C 1, and it contains two blocks with a cooler, the presence of which leads to a decrease in the fire extinguishing capacity of the device, one block includes a composite material containing ceramic fiber and a cooling agent for reducing the temperature of the aerosol jets, and the other - a cooling ultrafine-grained powder.

The closest analogue (prototype) of the proposed device is the solution according to patent RU 2767755C1, published on 21.03.2022, which discloses a device for volumetric aerosol fire extinguishing, which contains a housing equipped with a bottom and a nozzle cover, an aerosol-forming charge made in the form of a channelless checker and fixed inside the housing with a protective-fastening layer from the side surface, an afterburning chamber formed inside the housing, a launch unit installed in the cover, and an ejector nozzle connected to the housing. At the same time, in the central part of the end surface of the charge on the bottom side, a cavity filled with a flame extinguishing composition is made. The nozzle cover is equipped with nozzles with a critical section and thermal protection from the inside. Moreover, the nozzles are made in such a way that they pass through the cover with thermal protection and protrude outward from the outer surface of the cover. The known device provides high fire extinguishing capacity, including in large-volume premises. The disadvantage of this design is that high-temperature gases moving from the burning end of the checker can penetrate into the area of the upper part of the body and the place where it connects with the lid, which together can lead to intense heating and deformation of this part of the device, as well as damage to the paint layer. Disclosure of invention

The problem that the present invention is aimed at solving is to expand the range of volumetric aerosol fire extinguishing devices used, among other things, in rooms with large volumes.

The technical result of the proposed invention consists in ensuring the effective performance of the product under conditions of prolonged thermal exposure to structural elements.

To solve the problem and achieve the technical result, a device for volumetric aerosol fire extinguishing is proposed, comprising a housing equipped with a bottom and a nozzle cover, an aerosol-forming charge made in the form of a channelless pellet, a protective-fixing layer (PFL), an afterburning chamber formed inside the housing, a launch unit installed in the nozzle cover, and an ejector nozzle connected to the housing. At the same time, in the central part of the end surface of the charge on the bottom side, a cavity is made filled with a flame-extinguishing composition, the nozzle cover is equipped with nozzles with a critical section and thermal protection protruding into the housing. The nozzles are made in such a way that they pass through the nozzle cover with thermal protection and protrude outward from the outer surface of the nozzle cover. In this case, the device contains an anti-adhesive separating layer applied to the inner surface of the side wall of the housing and located between the protective-fastening layer and the said surface, wherein the protective-fastening layer has such a configuration that the outer side surface of the thermal protection of the nozzle cover contacts it.

A mixture of organosilicon compound with a cold-curing catalyst and mineral filler, including glass microspheres, is used as a protective-fastening layer. The checker is made from a composition with a negative oxygen balance, and potassium acid carbonate or azo compounds, or sulfonyl hydrazines, or nitroazo compounds, or acid azides, aluminum sulfate or its crystal hydrate or other compounds that release water vapor and other non-flammable gases during endothermic decomposition are used as a flame-extinguishing composition.

The cavity in the central part of the end surface of the charge from the bottom side is made cylindrical or conical.

The design of the proposed device ensures a jet flow of aerosol, in which individual jets do not merge with each other and do not intersect with the inner surface of the ejector nozzle, which ensures the absence of aerosol losses on the elements of the device design, as well as maintaining the temperature at the generator outlet at an acceptable level.

Brief description of the drawings

The invention is illustrated by a drawing which shows a general view of the device in section.

Embodiments of the invention

The device comprises a housing 1 provided with a bottom 2 and a nozzle cover 3, an aerosol-forming charge 4 made in the form of a channelless cartridge. The said cartridge is secured inside the housing by a protective-fastening layer 5 on the side of the side surface (this layer holds the charge in the housing and ensures combustion of the charge only from one end - from the side of the nozzle cover), an afterburning chamber 6 formed inside the housing 1, a launch unit 7 installed in the cover 3, and an ejector nozzle 8 connected to the housing. The afterburning chamber 6 is formed between the cover 3 and the charge 4. In this case, in the central part of the end surface of the charge 4 on the side of the bottom 2, a cavity 9 is made filled with a flame-extinguishing composition, i.e. a substance that decomposes with the absorption of heat and the formation of products that do not support combustion. The nozzle the cover 3 is provided on the inside with thermal protection 10, protruding inside the housing and nozzles 11 with a critical section. The nozzles 11 are made in such a way that they pass through the cover 3 with thermal protection 10 and protrude outward from the outer surface of the cover 3 in order to move high-temperature regions of the aerosol flow away from the cover 3 and reduce the level of its heating. Each nozzle 11 has a channel with a critical (smallest) section, made, for example, in the outlet part of the nozzle. The length of the nozzle section with the smallest section can be equal to approximately 0.5d, where d is the diameter of the critical section. The diameter of the critical section of the nozzle determines the length of the initial high-temperature region of the aerosol jet and its largest dimension should not exceed 10 ... 15 mm. The number of nozzles is determined depending on the total area of the critical sections required to ensure the operation of the device and design and technological considerations in the layout of the generator. The fastening of cover 3 to the body is ensured by a threaded connection, or by bendable elements, or by the use of expansion locking rings or rivets.

The aerosol-forming charge 4 is surrounded by a protective-fastening layer 5, which, in turn, contacts the thin-walled metal housing. The charge 4 and housing 1 are rigid elements, the ZKS 5 has a certain elasticity. The temperature coefficients of each of these elements are different. With temperature fluctuations, the elasticity of the ZKS 5 may be insufficient to compensate for the deformations that arise, and then delamination may occur either along the "charger-ZKS" boundary or along the "ZKS-housing" boundary. In this case, delamination along the "charger-ZKS" boundary is unacceptable. To prevent this delamination, before filling the gap between the wall of housing 1 and the fuel charge with the material of the protective-fastening layer 5, it is proposed to apply an anti-adhesive separating layer 15 to the inner surface of the side wall of the housing. Polyethylene film can be used as such a layer, various lubricants, for example: antifriction multipurpose lithium grease of the CIATIM-201 brand or similar, or a special separating lubricant based on wax or silicone. Thus, when manufacturing the proposed device, first an anti-adhesive separating layer 15 is applied to the inner side surface of the wall of the housing 1. Then a charge is installed in the housing 1 and the protective-fastening layer is poured directly into the housing 1 with the installed charge 4, wherein the configuration of the ZKS 5 is formed so that the thermal protection 10 of the cover 3 protruding into the housing contacts the ZKS 5 with its outer side surface (when the device is assembled), and the ZKS 5 reaches the place where the cover 3 is installed. In this case, "contacts" means that there is no technological gap between the thermal protection 10 of the cover 3 and the protective-fastening layer 5, however, the manufacturing accuracy does not always allow for full contact, and at some points of the contacting elements 10 and 5 there may be a minimum gap, the value of which should not be more than 2 mm. The absence of a gap means that hot gases will not have a strong thermal effect on the area where the body and cover meet, which increases the reliability of sealing this joint and, accordingly, prevents the cover and the part of the body near the cover from heating up and becoming deformed.

For example, marble dust and glass microspheres are used as mineral filler of the protective-fixing layer. Glass microspheres are inert, spherical particles based on, for example, sodium borosilicate glass, filled with air, characterized by high hardness, the bulk density of which is about 180...200 kg/ ^m3 . The mass of the ZKS using glass microspheres as mineral filler can be reduced by about 2.5 times.

Thermal protection 10 of cover 3 can be made of any non-flammable and heat-insulating material resistant to temperatures of about 1000°C material, for example, from a tablet coolant (based on basic magnesium carbonate), which can be retained by a cap 12 made of steel sheet connected to the lid, or by any other known method.

The installation and fastening of the device can be carried out using bracket 13. Metal ring 14 forms the volume of the combustion chamber and additionally provides thermal protection for the housing wall in the combustion chamber area.

The proposed device operates as follows. The launch unit 7 is triggered automatically by the fire protection system or is activated manually. The charge 4, located in the housing 1, is ignited. The end combustion of the charge 4 occurs in the direction from the cover 3 to the bottom 2. When the generator operation is completed, the cavity 9 is opened, and the substance enters into a reaction, which decomposes with the absorption of heat and forms products that do not support combustion, due to which the process of afterburning of underoxidized products formed when using AOS formulations with a negative oxygen balance is excluded after the end of the GOA operation. The flow of combustion products occurs in the direction from the burning end of charge 4 through the afterburning chamber 6 to the nozzles 11. The products formed during the combustion of charge 4 flow out through the nozzles 11 into the protected volume. With the proposed design of the nozzles, the aerosol streams do not intersect each other, each of them retains its characteristics, including the short length of the high-temperature initial section. The distance between the outlet sections of the nozzles and the surface of the cover, together with the thermal protection 10, as well as the presence of contact between the thermal protection of the cover and the protective-fastening layer, prevents the heating of the cover and the part of the body near the cover and their deformation.

Aerosol jets, passing through the cylindrical ejector nozzle 8, cool, mix with incoming air from outside and enter the protected volume, suppressing the source of the fire. Tests of the prototype device and the proposed device were conducted. The results are given in the examples.

Example 1.

The device, the design of which is described in the prototype, was tested to protect a room with a volume of up to 125 ^m3 with a fuel charge weight of 5 kg, an operating time of 115 s, and a generator housing diameter of 172 mm. The tests were conducted according to the ISO 15779 standard, the model fire source is a square steel tray measuring 500x500 mm, filled with n-heptane. The model fire source was successfully extinguished.

However, during the tests, a dangerous increase in pressure in the combustion chamber was observed. Analysis of the results showed that the most likely cause of this was local detachment of the ZKS from the side surface of the grenade. Also, after completion of the work, there were cases of burning of the paint coating on the body in the area of its connection with the nozzle cover.

Example 2. The design of the device according to the invention with a fuel charge weight of 5 kg, an operating time of 115 s, a generator housing diameter of 172 mm, was tested to protect a room with a volume of up to 125 m ³ . The charge used was a composition with a negative oxygen balance (composition of the KEP), containing (% by weight): potassium nitrate 70.4, dicyandiamide - 16.5, epoxy resin 5.2, iditol - 6.5, technological additives - 1.4. Aluminum sulfate crystalline hydrate, decomposing with heat absorption and formation of products that do not support combustion, was used as a flame-extinguishing composition located in a cavity formed in the central part of the end surface of the charge on the bottom side. The protective and fastening layer was made of a mixture of an organosilicon compound with a cold curing catalyst and a mineral filler with a dispersion of < 0.6 mm. During the manufacture of the proposed device, an anti-adhesive separating layer in the form of a silicone-based lubricant was applied to the inner side surface of the housing wall, and then a charge was installed in the housing and the protective coating was poured in. of the fastening layer directly into the housing with the installed charge, ensuring such a configuration of the ZKS that the thermal protection of the cover contacts it. The test was carried out according to the ISO 15779 standard, the model fire source is a square steel tray measuring 500x500 mm filled with n-heptane. The model fire source was successfully extinguished. There was no afterburning of gases when the device was stopped. No dangerous increase in pressure in the combustion chamber was observed. There was no burning of the paint coating on the housing in the area of its connection with the nozzle cover.

Example 3.

The design of the device according to the invention was tested with a fuel charge weight of 3 kg, an operating time of 80 s, a generator housing diameter of 172 mm, to protect a room with a volume of up to 60 m ³ . The charge was used as in Example 2, the protective and fastening layer was made of a mixture of organosilicon compound with a cold-curing catalyst and a mineral filler in the form of glass microspheres, which made it possible to reduce the weight of the product by 1.3 kg. The test was carried out according to the ISO 15779 standard, as in Example 2. The model fire was successfully extinguished. There was no afterburning of gases when the device was stopped. No dangerous increase in pressure in the combustion chamber was observed. There was no burning of the paint coating on the housing in the area of its connection with the nozzle cover.

As the test results show, the proposed design ensures stable and effective performance under conditions of long-term (more than 40 s) thermal impact on structural elements in protected areas of various volumes, including large ones, without combustion of gases flowing out of the nozzles of the device at the final stage of its operation, without deformation of the device, and also without damage to the paint layer.

Claims

Invention formula 1. A device for volumetric aerosol fire extinguishing, comprising a housing provided with a bottom and a nozzle cover, an aerosol-forming charge made in the form of a channelless pellet, a protective-fastening layer, an afterburning chamber formed inside the housing, a launch unit installed in the nozzle cover, and an ejector nozzle connected to the housing, wherein in the central part of the end surface of the charge on the bottom side there is a cavity filled with a flame-extinguishing composition, the nozzle cover is provided with nozzles with a critical cross-section and thermal protection protruding into the housing, the nozzles are made in such a way that they pass through the nozzle cover with thermal protection and protrude outward from the outer surface of the nozzle cover, characterized in that the device contains an anti-adhesive separating layer applied to the inner surface of the side wall of the housing and located between the protective-fastening layer and the said surface, wherein the protective-fastening layer has such a configuration that the outer side surface of the nozzle cover thermal protection contacts it. 2. The device according to item 1, characterized in that a mixture of an organosilicon compound with a cold-curing catalyst and a mineral filler, including in the form of glass microspheres, is used as the protective-absorbing layer. 3. The device according to item 1, characterized in that the checker is made from a residue with a negative oxygen balance, and the flame-extinguishing residue is potassium acid carbonate or azo compounds, or sulfonyl hydrazines, or nitroazo compounds, or acid azides, aluminum sulfate or its crystal hydrate or other endothermic compounds that release water vapor and other non-flammable gases upon decomposition. 4. The device according to item 1, characterized in that the cavity in the central part of the end surface of the charge from the bottom side is made cylindrical or conical.