RU2822833C1 - Net cassette for installation of combined fire extinguishing with air-mechanical hybrid foam of medium expansion or sprayed water and method of its production - Google Patents

Abstract

FIELD: fire-fighting equipment.

SUBSTANCE: group of inventions relates to a mesh cassette for a combined fire extinguishing of air-mechanical foam of medium expansion or sprayed water, comprising a housing, a mesh cassette installed in the housing, a shaft and means for supplying a foaming agent solution or water to the mesh cassette and into the shaft under pressure, and to a method of making such a mesh cassette, which is made with a through hole in the grids for placing the barrel in it and contains coaxially installed one inside the other annular inner rim, containing an annular cage with a through hole for placing a barrel in it, an intermediate rim and an outer rim and two grids located with a gap relative to each other, one of which, the first mesh, is fixed by the edges in the gap between the mating side surfaces of the inner and intermediate rims, and the other, second mesh is fixed by its edges in the gap between the mating side surfaces of the intermediate and outer rims, note here that said meshes have coaxial holes that are commensurate with cage through hole with mesh edges locked on said cage by means of circular washers and screws. Mesh cassette is made by laying meshes, laid between coaxially installed relative to each other inner, intermediate and outer rims and by means of axial movement of the rims one net is pulled on the bottom of the inner rim and the second net is pulled on the top of the intermediate rim and the edges of the second net are fixed in the gaps between the mating side surfaces of the rims.

EFFECT: invention discloses a cassette of grids for a combined fire extinguishing installation with an air-mechanical hybrid foam of medium expansion or sprayed water and a method of its production.

13 cl, 25 dwg, 1 tbl

Description

Technical field

The invention relates to fire-fighting equipment, to manual and stationary devices for generating air-mechanical hybrid foam of medium expansion or sprayed water and can be used in the manufacture of fire-technical equipment used in extinguishing various forestry, emergency transport, emergency industrial and other large-scale fires fires, in particular when extinguishing fires of flammable and combustible liquids, liquefied natural and hydrocarbon gases (LNG and LPG), solid combustible materials, vehicles and industrial technical equipment, as well as for creating heat shields and cooling with sprayed water in areas of accidents and disasters , natural disasters, for degassing and decontamination, camouflage of civil and military objects.

State of the art

It is known that the most effective modern fire extinguishing agent is the air-mechanical hybrid foam of medium expansion, previously proposed by the applicant’s authors, consisting of polydisperse bubbles with a thickened (watered) shell - reduced (low) expansion foam, and bubbles with a thinned (dehydrated) shell - high foam (medium) expansion, forming, when mixed in the process of joint movement, a hybrid foam of medium expansion [RU 2757106, A62C 5/02, publ. 10/11/2021, BI 29; RU 2757479, A62C 5/02, publ. 10/18/2021, BI 29].

There are known generators of air-mechanical foam of medium expansion in portable and stationary design options, however, most of the well-known generators of medium expansion foam by other authors provide foam jets with a range of up to 10 m, which limits their use when extinguishing large-scale fires due to the high risk of working in the area fire personnel of fire departments.

A mobile multi-purpose foam generating unit is known for generating foam mainly at nuclear fuel cycle facilities, including a container for water or a foam concentrate solution, a pump with an electric motor, a comb for connecting air-foam generators (foam generators) with an average expansion rate of K = 20-200 and fire nozzles, pipelines, hoses and fittings, is additionally equipped with low expansion foam generators (K<20) and high expansion foam (K=200-1000), working with two types of mesh (conventional - flat or metal fabric - volumetric weaving), and a valve is installed on the comb, allowing smoothly regulate the flow of the foaming solution supplied to the high-expansion foam generator at a flow rate of 0.5-10 l/min. In addition, the container is equipped with a lid designed to seal it when creating a pressure of up to 6 atm. These features provide increased versatility of the installation [RU 2308996 A62S 27/00, A62S 5/02, publ. 27.10.2007].

The disadvantage of the device according to RU 230899 is its significant weight and dimensions, low performance and the impossibility of its use when extinguishing fires in industrial and low-rise buildings in urban and rural settlements, extinguishing forest and landscape fires.

A device previously developed by the applicant’s authors for forming a jet of medium expansion foam with increased range is known, according to which, in order to increase productivity, economy and increase the efficiency of fire extinguishing by creating a combined jet of foam of medium expansion and increasing the range of the jet of medium expansion foam up to 20 m, a foaming agent solution is supplied to the mesh in the body of the foam generator to produce a jet of foam of medium expansion with increasing expansion and decreasing density in the direction from the center to the periphery by means of a means or means located on the mesh or inside the mesh cassette for redistributing the amount of foaming solution on the surface of the mesh, made in the form of a ring, rings, ring nozzles or other means located inside the mesh cassette and/or on the surface of the mesh or mesh cassette on the supply side of the foaming solution jet or on the foam outlet side. The body of this foam generator is made in the form of a hollow cylinder, to which a nozzle or other means of forming a jet of foam solution is attached on the supply side of the foam agent solution, and a mesh is attached inside the body on the foam outlet side. The body of the foam generator has a length of 0.3 to 1.5 times the distance from the means for forming a jet of foam solution to the mesh. The foam generator additionally contains a diffuser in the form of a hollow cylinder, fixed in the body of the foam generator directly behind the mesh on the foam outlet side and made with a length of 0.1 to 0.9 times the diameter of the diffuser and a free cross-sectional area less than the cross-sectional area of the mesh [RU 2170123 A62C 5/02 , publ. 07/10/2001].

The disadvantages of the device according to RU 2170123 are the complexity of the design of the means or means for redistributing the amount of foaming solution on the surface of the mesh, as well as the lack of information about the features of fastening the mesh in the device and the design of the mesh cassette.

There is a known method, previously developed by the authors of the applicant, of forming a jet of medium-expansion foam with increased range and a device for its implementation, according to which increasing the productivity, economy and efficiency of fire extinguishing with combined medium expansion foam while simultaneously simplifying the manufacture, transportation and use in fire extinguishing systems, when receiving a jet of foam, a jet of foam concentrate solution is supplied to the mesh in the foam generator body under pressure RP in front of the nozzles from 0.4 to 1.2 MPa. In a device for forming a jet of medium expansion, containing a housing and a mesh located in the housing, the body of the foam generator is made in the form of a hollow cylinder or two or more half-cylinders connected to each other by planes, while a mesh is fixed inside the body on the foam outlet side, the body of the foam generator has a length from 0.3 to 1.5 distances from the means for forming a jet of foaming agent solution to the mesh, and the means for forming a directed jet of foaming agent solution is made in the form of a nozzle or nozzles or other means for forming a directed jet or jets, located or located at a distance from the mesh, determined by formula , where A is the distance from the center of the nozzle or other means of jet formation to the mesh, m; Rs - radial mesh size; tgα/2 is the tangent of half the opening angle of the foam solution jet; α is the angle of opening of the foam solution jet at the exit from the nozzle or other means of forming a directed jet [RU 2180607, A62C 5/02, publ. 03/20/2002, Bulletin. No. 8].

The disadvantages of the device according to RU 2180607 and other known foam-generating devices are the lack of information about the features of fastening the mesh in the device, about the design and manufacturing technology of the mesh cassette as a determining design factor of reliability and influence on the quality of the resulting foam.

The closest in technical essence and achieved technical result (prototype) is the medium-expansion foam generator GPS-600 in accordance with GOST R 50409-92, containing a conical generator body made of cast aluminum alloy AK7 or other alloys with a nozzle on the foam outlet side and a conical collector (confuser) from the supply side of the sprayed foam solution to the grids, a grid cassette in the form of a ring, covered along the end planes with a metal mesh with a cell size of 0.8-1 mm, a vortex-type centrifugal sprayer with a GM-70 connecting head attached to the body by means of three stands [GOST R 50409-92 Medium expansion foam generators. Technical conditions. Official publication. Gosstandart. Moscow, 8 p. (prototype)].

The GPS 600 generator (prototype), according to its operating principle, is a portable water-jet ejector apparatus.

The nozzle in the GPS-600 generator is designed to form a foam flow after a grid cassette into a compact jet and increase the flight range of medium-expansion foam up to 10 m.

The vortex-type sprayer in the GPS-600 generator has six windows located at an angle of 12°, which causes swirling of the flow of working fluid and ensures that a sprayed stream of foam solution is obtained at the output, covering the entire surface area of the grid cassette.

The GPS-600 generator (prototype) functions as follows: The sprayed stream of foaming agent solution emerging from the atomizer, due to ejection and the reduced pressure created inside the housing, sucks in atmospheric air through a conical collector (confuser) and mixes with it in the housing.

A mixture of droplets of foaming solution and air falls on the mesh cassette.

On grids, deformed drops form a system of stretched films, which, enclosed in limited volumes, form first elementary (in the form of individual bubbles) and then mass foam.

With the energy of newly arriving droplets and air, the mass of foam is pushed out of the foam generator and with the formation of a jet of air-mechanical foam of medium expansion with a multiplicity of 100 + 30, obtained as a result of intensive mixing in the GPS-600 generator in a certain proportion of three components: water, foaming agent and air [Moiseev Yu.N., Kharlamov R.I., Kolbashov M.A.. Fire-technical and emergency rescue equipment. Tutorial. - Ministry of the Russian Federation for Civil Defense, Emergency Situations and Disaster Relief. Federal State Budgetary Educational Institution of Higher Education Ivanovo Fire and Rescue Academy of the State Fire Service. Ivanovo, 2017, pp. 36-38].

The main technical disadvantage of the GPS-600 generator (prototype) is the insufficient (only about 8-10 m) range of medium expansion foam supply, as well as insufficient operational reliability. In particular, the probability of failure-free operation of GPS-600 for 50 hours of operation, or failure-free operation of GPS-2000 for 25 hours of operation, specified in GOST R 50409-92 (p. 7, clause 2.19) is 0.993 at a nominal pressure of the foam concentrate solution in front of the sprayer of 0.0, 4-0.6 MPa (4-6 kg/cm ² ) proves the relatively low reliability of GPS foam generators, due to the possible destruction of the grid cassette with the tearing of the grids from their fastening points and the cessation of their normal operation as a result of the dynamic pressure of the flows acting on the grids. This significantly limits the scope and effectiveness of the GPS-600 generator and increases the risk of danger for fire personnel.

A common disadvantage of the known water-foam fire extinguishing devices is that the known stationary and mobile devices for generating medium-expansion foam with relatively low reliability and the inability of normal operation at high pressure of the foam solution or water supplied to them have a relatively low operating efficiency due to insufficient range and generation productivity and supplying medium expansion foam.

At the same time, in the well-known publicly available sources of information about medium-expansion foam generators, there is practically no information about the design features and manufacturing technologies of mesh cassettes or mesh packages and fastening in the mesh body, which are the main working element of medium-expansion foam generators, loaded by the dynamic pressure of the flow of foam concentrate solution or water.

Problem solved and technical result

An inventive problem that has not been properly resolved to date, hindering the increase in productivity and efficiency of modern fire extinguishing technologies and equipment, is that the known foam generators of medium expansion or bulky, complex and low-tech to manufacture, or do not provide the required efficiency in extinguishing large and fast-moving fires. reasons for insufficient performance and range, since it is known that when extinguishing large-scale industrial, forest, emergency transport and emergency industrial fires, controlled, rapid and uniform coverage of the entire fire-hazardous area with fire extinguishing agents is required, preferably air-mechanical foam of medium expansion from the most remote positions.

The technical problem to be solved by the claimed invention is the need to quickly prevent fires and explosions, reduce the intensity of combustion and extinguish large-scale fires through the rapid formation and long-range distribution of air-mechanical foam of medium expansion or sprayed water over large areas of fire of flammable liquids, solid combustibles materials, liquefied natural and hydrocarbon gases (LNG and LPG), when and where to prevent fires and extinguish fires, prompt coverage of the entire fire-hazardous area with a fire extinguishing agent is required, as well as cooling and fire protection of buildings, structures, machinery, equipment, flammable and adjacent to the fire explosive materials. This is possible only if there is and use of a sufficient number of structurally simple and technologically advanced, but convenient and effective in operation, long-range devices for generating medium-expansion foam or atomized water in manual and stationary installations of various designs, which is not observed at present.

The technical result achieved by implementing the claimed invention is to increase the efficiency of extinguishing emergency transport, forest, industrial and other fires through the creation, mass production and widespread practical use of structurally simple, technologically advanced and reliable in operation combined hybrid extinguishing installations medium expansion foam or sprayed water with increased range.

Disclosure of the invention

The problem (task) is solved and the required technical result is achieved by the fact that according to the invention, a grid cassette for installing combined fire extinguishing with air-mechanical hybrid medium-expansion foam or sprayed water, containing a housing, a grid cassette installed in the housing to form medium-expansion foam or sprayed water, a barrel for forming low-expansion foam or sprayed water and a means of supplying a foaming agent solution or water under pressure to the grid cassette and into the barrel, made with a through hole in the grids to accommodate a barrel of low-expansion foam or sprayed water and contains coaxially installed rings, one inside the other, with cylindrical side surfaces, an inner rim containing an annular holder with a through hole installed in it by means of flat, parallel to the direction of movement in the housing flows of a foaming agent solution or water in the fin installation housing, an intermediate rim and an outer rim and two meshes located with a gap relative to each other, one of which, the first mesh, is fixed by its edges in the gap between the mating side surfaces of the inner and intermediate rims, and the other, the second mesh, is fixed by its edges in the gap between the mating side surfaces of the intermediate and outer rims, while There are holes in the meshes in front of and above the hole in the cage, and the edges of the meshes near the through hole of the cage are fixed by means of ring washers fastened to the cage.

In this case, the outer contour of the mesh cassette is made of an oval shape with semicircular side edges and a flat top and a flat bottom mating with them, the inner and intermediate rims with the edges of the first mesh fixed in the gap between their mating side surfaces are installed one inside the other with interference and are additionally fixed with each other each other by spot welding, and the intermediate and outer rims with the edges of the second mesh fixed in the gap between their mating side surfaces are coaxially installed one inside the other with interference and are additionally fixed to each other by spot welding.

In this case, the mesh cassette is made with the possibility of forming a combined flow (jet) of air-mechanical hybrid foam of medium expansion or sprayed water, obtained as a result of turbulent shockless mixing in the process of joint co-movement of jets of air-mechanical foam of medium expansion or sprayed water formed on the grids and in contact with them from below a jet of low expansion air-mechanical foam or sprayed water formed in the barrel.

The posed problem (task) is solved and the required technical result is also achieved by the fact that when manufacturing the above-described grid cassette for installing combined fire extinguishing with air-mechanical hybrid foam of medium expansion or sprayed water containing a housing, a cassette of grids installed in the housing for forming medium expansion foam or atomized water, a barrel for forming low-expansion foam or sprayed water and a means of supplying a foaming agent solution or water under pressure to the grid cassette and into the barrel, according to the invention, the grid cassette is made with a through hole in the grids to accommodate a barrel of low-expansion foam or sprayed water containing coaxially installed one inside the other, annular, with cylindrical side surfaces, an inner rim containing an annular holder with a hole for a barrel of low-expansion foam or sprayed water installed in it by means of flat, parallel to the direction of flow of foam solution or water flows in the fin installation body, an intermediate rim and an outer an annular rim and two meshes located with a gap relative to each other, one of which, the first mesh, is fixed by its edges in the gap between the mating side surfaces of the inner and intermediate rims, and the other, the second mesh, is fixed by its edges in the gap between the mating side surfaces of the intermediate and outer rims, in this case, holes are made in the first and second grids under and above the through hole of the cage, and the edges of the first and second grids near the through hole of the cage are rigidly fixed by means of ring washers fastened to the cage.

When manufacturing a mesh cassette, the first mesh is placed between an inner rim coaxially installed relative to each other, containing an annular holder with a hole for placing a barrel of low-expansion foam or sprayed water, and an intermediate rim, and by means of axial movement of the inner rim relative to the intermediate rim, the inner rim is pushed in with interference inside the intermediate rim with pulling the first mesh onto the bottom of the inner rim and fixing the edges of the first mesh in the gap between the mating side surfaces of the intermediate rim and the inner rim,

then a second mesh is placed on top of the inner and intermediate rims combined with each other with the first mesh stretched over the bottom of the inner rim, the outer rim is coaxially installed above them and by means of axial movement of the outer rim relative to the intermediate and inner rims aligned with each other with the inner rim stretched over the bottom the first mesh is used to push the outer rim onto the intermediate and inner rims aligned with each other, with the second mesh stretched over the top of the intermediate rim and the edges of the second mesh secured in the gap between the mating side surfaces of the outer and intermediate rims,

after that, on the outer sides of the mesh above and below the through hole in the cage, holes are cut out in the mesh for a barrel of low-expansion foam or sprayed water, washers with holes are placed above them to accommodate a barrel of low-expansion foam or sprayed water, and the washers are fastened with screws to the edges of the cage with tightly fixing the edges of the holes in the first and second mesh around the hole in the cage to obtain a through hole in the cassette for subsequent placement of a barrel of low-expansion foam or sprayed water in it.

In this case, in the process of manufacturing a mesh cassette, after stretching the first mesh onto the bottom of the inner rim, the edges of the first mesh protruding above the rims are cut off and the position of the inner and intermediate rims relative to each other is fixed by spot welding, and after stretching the second mesh onto the top of the intermediate rim, the edges of the second mesh protruding above the rims cut off and fix the position of the outer and intermediate rims relative to each other by spot welding, or after pulling the second mesh onto the top of the intermediate rim, the edges of the second mesh protruding above the rims are bent along the side surface of the outer rim and spot welding fix the position of the outer and intermediate rims relative to each other to obtain options design of the mesh cassette described above.

Brief description of drawings

The invention is illustrated by drawings, where in FIGS. 1-25 the design and manufacturing technology of the proposed grid cassette for the installation of combined fire extinguishing with air-mechanical hybrid foam of medium expansion or sprayed water is disclosed in detail, the design of the installations for which it is intended and in which the proposed grid cassette can be used is shown, examples of various options for implementing combined installations are presented. fire extinguishing with examples of their practical real use in extinguishing various fires.

In FIG. 1, 2 and 3 show a side view, a top view and a general view of a combined fire extinguishing installation of air-mechanical hybrid foam of medium expansion or sprayed water of the type produced by the applicant of UKTP PURGA 20, 30 or 40 installations, in which the proposed mesh cassette can be used, and where position numbers indicate: nozzles 1 for supplying a fire extinguishing agent (foaming agent solution or water) to the grids for forming air-mechanical foam of medium expansion or sprayed water; barrel 2 low expansion foam or sprayed water; an oval-shaped body 3 with semicircular side and mating flat upper and lower surfaces, on which, on the side of the exit of foam or sprayed water from the grid cassette 4, there is an annular protrusion 6 concave into the surface of the housing 3, and on the side of the means for supplying the fire extinguishing agent to the grid cassette, there is an annular protrusion 5 convex to the outside of the housing surface; installed inside the housing with an emphasis on the protrusion 6 concave inside the housing, a cassette of grids 4 for forming air-mechanical foam of medium expansion or sprayed water; stops 7 for rigidly fixing the relative position of the housing 3 and the distribution manifold 19 with nozzles 1; means of supplying the fire extinguishing agent to the nozzles 1 and to the barrel 2 by means of a distribution manifold 19 and a means of connecting to the supply pipeline of the fire extinguishing agent 20 in the form of a quick-release/detachable connection with rotary eccentric clamps of the camlock type, or a standard connecting head, or a flange with holes for bolting; protective plastic rims 8 along the edges of the body 3 washers 16 and screws 17 securing the edges of the mesh on the mesh cassette installed inside the mesh cassette by means of ribs 18 with a hole in it for a barrel 2 of low expansion foam or sprayed water; folding handle 21 for controlling the generator in its manual version.

In fig. 4-7 show diagrams of the manufacturing stages, the intermediate and final design of the grid cassette 4, containing an internal annular rim 10, inside of which, by means of flat ribs 18, a holder 9 is installed with a hole for placing a barrel 2 of low-expansion foam or sprayed water; intermediate rim 11; outer rim 12; first grid 13; second grid 14; places for fixing by spot welding 15 the relative position of the rims 10, 11 and 12 after their coaxial installation with interference into each other with fixation of the edges of the meshes 13 and 14 in the gaps between their side surfaces;

In FIG. Figure 4 shows a diagram of the 1st stage of manufacturing a mesh cassette with stretching the first mesh 13 onto the bottom of the inner rim 10 with fixing the edges of the mesh 13 between the side surfaces of the inner 10 and intermediate 11 rims and spot welding 15 for additional fixation of the inner 10 and intermediate 11 rims to each other and the edges mesh 13 between their side surfaces.

In FIG. Figure 5 shows a diagram of the 2nd stage of manufacturing a mesh cassette with stretching the second mesh c14 onto the top of the intermediate rim 11 with fixing the edges of the mesh 14 between the side surfaces of the intermediate 11 and outer rims 12 and spot welding 15 for additional fixation of the intermediate 11 and outer 12 rims to each other and the edges mesh 14 between their side surfaces.

In FIG. 6 shows a diagram of the 3rd stage of manufacturing a grid cassette with cutting out holes in the grids 13 and 14 above and below the through hole in the cage 9 installed by means of the ribs 18 in the inner rim 10 and fixing the edges by fixing the edges of the holes in the grids 13 and 14 on the cage to the cage 9 using washers 16 and screws 17.

In FIG. 7 shows a diagram of a design option for a net cassette with additional wrapping of the edges of the mesh 14 on the sides of the outer rim 12 to strengthen the fastening of the mesh 14 in the net cassette.

In FIG. 8 and 9 photos of the installation with a grid cassette in stationary and mobile versions with manual control.

In fig. 10 and 11 – photos of the installation with a grid cassette in the form of an attachment to an auto-foam lifter, respectively, without rotation units and with rotation units and . remote control.

In FIG. 12 – photo of the installation with a net cassette in the form of an attachment to a remote-controlled car lift.

In FIG. 13 – photo of an installation with a remote-controlled net cassette in a stationary version on a fire truck.

In FIG. 14 – photo of the installation with a grid cassette in a mobile (portable) version with manual control, oscillator and quick-release connection.

In FIG. 15 – photo of the installation with a grid cassette in a stationary explosion-proof design with remote control.

In FIG. 16 – photo of the installation with a net cassette in the form of an attachment to a stair lift with a remote control.

In FIG. 17 – photo of the installation with a net cassette on a fire boat.

In FIG. 18 and 19 irrigation map and operating radius of the installation with a grid cassette.

In FIG. 20, 21, 22, 23, 24 and 25 – photos of examples of practical application of the installation with a net cassette.

Carrying out the invention

The grid cassette proposed by the invention is intended for possible use in various design installations for combined fire extinguishing with air-mechanical hybrid foam of medium expansion or sprayed water, used in extinguishing various forest, emergency transport, emergency industrial and other large-scale fires, in particular when extinguishing fires of flammable and combustible liquids, liquefied natural and hydrocarbon gases (LNG and LPG), solid combustible materials, vehicles and industrial technical equipment, as well as for creating light and heat shields and cooling in areas of accidents, disasters, natural disasters, for degassing and decontamination, camouflage of civilian and military objects.

Characteristic structural, causally related to the achieved technical result, distinctive features of the use of the proposed mesh cassettes with the possibility of their installation in installations for combined fire extinguishing with air-mechanical hybrid foam of medium expansion or sprayed water, containing a housing, a mesh cassette installed inside the housing and a means supplying a fire extinguishing agent (foaming agent solution or water) to the mesh cassette, as well as a means of connecting to the pressure pipeline for supplying the fire extinguishing agent (aqueous solution of foaming agent or water), are:

- The ability to simply and reliably fix a grid cassette in the installation body;

- The possibility of manufacturing and using almost the same simple and technologically advanced, but convenient and effective to use design of a mesh cassette, suitable for installation in manual and stationary installations of various performance and design;

- Possibility of installing and fixing a grid cassette inside the generator housing at an optimal distance from the means of supplying the fire extinguishing agent to the grid package;

- Possibility of manufacturing a mesh cassette, structurally formed by three coaxial outer, intermediate and inner ring rings located with interference one inside the other and two tightly and evenly stretched meshes located at an optimal distance from each other (about 20 mm), tightly and securely fixed edges in the gaps between these three rims with possible additional fixation by spot welding of both said annular rims to each other and said meshes to the rims.

This original design of the mesh cassette provides not only a tight, uniform tension of the meshes, rigid and reliable fixation of the meshes in the cassette and the mesh cassette inside the installation body at an optimal distance from the nozzle, but also ensures the effective formation of two long-range combined jets of medium expansion foam or sprayed water by two meshes located with an optimal gap relative to each other, as well as a jet of low expansion foam or sprayed water in contact with them to obtain a single combined jet of air-mechanical hybrid foam or sprayed water;

- The ability to place a mesh cassette inside the unit body so that the mesh fixed between the outer and intermediate rims is facing the nozzle, and the mesh fixed between the intermediate and inner rims is facing towards the exit of the foam jet, which allows not only to significantly increase the reliability of the design and long-term normal operation of the grid cassette in foam generators under extreme conditions, even with a pressure at the inlet of the fire extinguishing liquid above 1.2 MPa (12 kg/cm ² ), but also to ensure the formation and supply of a combined jet of hybrid foam of medium expansion or sprayed water with increasing expansion and decreasing density in the direction from the center to the periphery at a distance of more than 40-55 m.

All this proves the confident achievement of the required technical result in the implementation and use of the invention, namely, the implementation of the invention provides the opportunity to increase the efficiency of extinguishing emergency transport, forest, industrial and other fires through the creation, mass production and widespread practical use of structurally simple, technologically advanced manufacturing and reliable operation of the mesh cassette proposed according to the invention in medium expansion foam generators with increased range.

As shown in the drawings, almost the same design of a mesh cassette can be used in various design installations for combined fire extinguishing with air-mechanical hybrid foam of medium expansion or sprayed water in manual and stationary versions, with oscillating devices and with remote control in fire extinguishing systems, in design for fresh and sea water.

Installations for combined fire extinguishing with air-mechanical hybrid foam of medium expansion or sprayed water using the proposed mesh cassette can be equipped with standard quick-release connections (type TZA, Kamlok, flange connections, etc.), allowing them to be installed and used on all types of domestic and foreign fire equipment.

Standard and specially designed connections ensure quick and easy installation of the foam generator with the proposed mesh cassette on stationary and mobile equipment and in fire extinguishing facility systems, as well as the possibility of using them either as barrels with GM connecting heads in accordance with GOST R 53279-2009, or as nozzles on stationary and auto-mechanical ladders, or as attachments for auto-foam lifts, or as stationary installations with flange connections, etc.

If there are rotation units, installations with the proposed grid cassette can be produced with manual control, with wired or radio remote control for turning the generator in horizontal and vertical planes; with combined switchable manual and remote control.

The proposed mesh cassette can be mounted both on manual installations of various designs, and in installations placed on mobile hand carts, cars and car trailers, sea vessels, industrial premises, public and residential buildings, etc. in stationary version.

Thus, all individual essential features and the totality of essential features of the invention shown in detail in the drawings and in the description are essential and are in a cause-and-effect relationship with the technical result obtained from the use of the invention.

Structurally, the proposed grid cassette contains three coaxially installed with interference one inside the other and the inner 10, intermediate 11 and outer 12 ring rims and two tightly stretched grids located with a gap relative to each other, one of which 13 is fixed by the edges in the gap between the outer and intermediate rims, and the other mesh 14 is fixed by its edges in the gap between the intermediate and inner cylindrical annular rims.

In this case, an annular holder 9 with a through hole to accommodate a barrel of low-expansion foam or atomized water is installed and secured in the inner rim by means of flat ribs 18 parallel to the direction of movement of the foam solution or water flows in the housing (Fig. 4-7).

The proposed mesh cassette is manufactured as follows (diagrams of sections at individual stages of its production in Fig. 4-7):

The first mesh 13 is placed between the inner rim 10, installed coaxially relative to each other, containing an annular holder 9 with a hole for placing a barrel 2 of low-expansion foam or sprayed water in it, and an inner rim, inside of which, by means of flat ribs 18, a holder 9 with a hole for placing it contains 2 barrels of low expansion foam or sprayed water.

By axial movement of the inner rim 10 relative to the intermediate rim 11, the inner rim 10 is pushed with tension inside the intermediate rim 11 with the first mesh 13 stretched onto the bottom of the inner rim 10 and the edges of the first mesh 13 fixed in the gap between the mating side surfaces of the intermediate rim 11 and the inner rim 10.

Then, a second mesh 14 is placed on top of the inner 10 and intermediate 11 rims aligned with each other with the first mesh 13 stretched over the bottom of the inner rim 10, the outer rim 12 is coaxially installed above them, and by axial movement of the outer rim 12 relative to the intermediate 11 and aligned with each other of the inner 10 rims with the first mesh 13 stretched over the bottom of the inner rim, push the outer rim 12 onto the intermediate 11 and inner 10 rims aligned with each other, pulling the second mesh 14 onto the top of the intermediate rim 11 and fixing the edges of the second mesh in the gap between the mating side surfaces of the outer 12 and intermediate 11 rims.

After this, on the outer sides of the meshes 13 and 14 above and below the hole in the cage 9, holes are cut out in the meshes for the barrel 2 of low-expansion foam or sprayed water, washers 16 with holes for placing the barrel 2 of low-expansion foam or sprayed water are placed above the holes cut in the meshes and by means of screws 17, washers 16 are fastened to the edges of the cage 9 with tight fixation of the edges of the holes in the first 13 and second 14 grids around the hole in the cage 9 to obtain a through hole in the cassette for subsequent placement of a barrel 2 of low expansion foam or sprayed water.

In this case, in the process of manufacturing a mesh cassette, after pulling the first mesh 13 onto the bottom of the inner rim 10, the edges of the first mesh 13 protruding above the rims 10 and 11 are cut off and the position of the inner 10 and intermediate 11 rims relative to each other is fixed by spot welding, and after pulling the second mesh 14 onto the top of the intermediate rim 11, the edges of the second mesh 14 protruding above the rims are cut off and the position of the outer 12 and intermediate 11 rims relative to each other is fixed by spot welding, or after pulling the second mesh 14 onto the top of the intermediate rim 11, the edges of the second mesh 14 protruding above the rims 11 and 12 are bent along the side surface of the outer rim 12 and spot welding fix the position of the outer 12 and intermediate 11 rims relative to each other, obtaining design options for the mesh cassette described above.

The proposed mesh cassette can use a mesh with nominal dimensions of the sides of the cells in the clear 0.8-1.12 mm in accordance with GOST 3826, made of wire with a diameter of 03.04 mm from high-alloy steel, or a mesh in accordance with GOST 6613 from semi-pompak wire with the same dimensions cells and wire diameter.

The installation of combined fire extinguishing (UKTP) with air-mechanical hybrid foam of medium expansion or sprayed water, using the example of the UKTP PURGA 30 produced by the applicant, with the proposed grid cassette is manufactured as follows (Fig. 1-3):

A rectangular blank is cut out of a thin-walled metal sheet of predominantly stainless steel or ordinary painted steel, from which a cylindrical body 3 of the required dimensions is made by bending and welding, on which on one side (from the side where the foam stream exits) an annular protrusion 6 with a radius, concave into the body 3, is formed from 3 to 5 mm, and on the other side (from the side of subsequent installation of the nozzle 4) an outward convex annular protrusion 5 with a radius of 3 to 5 mm is formed

A grid cassette 4, prefabricated using the technology described in detail above, is installed inside the housing 3 on the side of subsequent installation of injectors 1 with an emphasis on the annular protrusion 6 concave inside the housing so that the mesh 13, fixed by the edges between the outer 12 and intermediate 11 rims, faces the direction of subsequent installation of injectors 1, and the mesh 14 fixed by the edges between the intermediate 11 and inner 10 rims (Fig. 6, 7) was turned towards the exit of jets of foam or sprayed water, which ensures maximum reliability, strength and durability of the normal functioning of the mesh.

The grid cassette 4 in housing 3 is fixed from the outside with screws or self-tapping screws.

Then protective plastic hoops 8 are put on the edges of the body 3, stops 7 are screwed to the body and screws or self-tapping screws 19 are screwed to the distribution manifold 19 with a means of connection to the fire extinguishing agent supply pipeline 20, made in the form of a quick-release/detachable connection with rotary eccentric camlock type clamps, or a standard connection head, or a flange with holes for bolting to the fire extinguishing agent supply line.

The figs shown in the photo are manufactured in a similar manner. 8-17 design options for the installation with the proposed mesh cassette and with various means of connecting the installation to the pressure pipeline for supplying the fire extinguishing agent solution in the form of a foaming agent solution or water.

Individual parts and assemblies of the inventive grid cassette and installations using it can be made from structural elements and materials commonly used in fire-fighting technology, on conventional equipment, using conventional technologies known and used in the field of modern fire-extinguishing and fire-explosion prevention technology.

An installation for combined fire extinguishing with air-mechanical hybrid foam of medium expansion or sprayed water (UKTP) with the proposed grid cassette, using the example of the type produced by the applicant as UKTP PURGA 30, functions as follows (Fig. 20-25):

A solution of foaming agent or water from the pressure pipeline is supplied to nozzles 1, from where, under a working pressure of 0.8-1.2 MPa, it is supplied to the central zone of the grid cassette 4 and to the barrel 2.

At the same time, due to the ejection effect and vacuum created by a conical flow of foaming agent solution or water, expanding in the direction of movement from the nozzles to the grid cassette, atmospheric air is sucked into the peripheral zones of the grid cassette.

Inside the grid cassette between grids 13 and 14, drops of a foaming agent solution or water and peripheral air flows are mixed to produce a combined jet of medium expansion foam or sprayed water at the exit from the grid cassette and from the diffuser with increasing expansion and decreasing density in the direction from the center to the periphery.

As a result, at the exit from housing 3, two streams of combined air-mechanical foam of medium expansion are formed, consisting of polydisperse bubbles with a thickened (watered) shell located in the central part of the flow - foam of reduced expansion, and bubbles with a thinned (dehydrated) shell located in the peripheral parts of the flow. shell - foams of increased expansion, which, when further mixed in the process of joint movement, form a hybrid foam of medium expansion with increased fire-extinguishing properties and an increased supply range.

At the same time, a jet of low-expansion foam or sprayed water is formed in barrel 2, which, in contact with the jets of medium-expansion foam emerging from the mesh cassette during their joint co-movement, forms and provides a remote supply of a single combined jet of hybrid foam of medium expansion or sprayed water.

Flows of hybrid foam of medium expansion or sprayed water with increasing expansion and decreasing density in the direction from the center to the periphery, formed by installations with the proposed grid cassette, have a significantly increased range compared to homogeneous flows due to the presence in the central part of a flow with increased density and increased kinetic energy .

It is known that foam is the most effective and widely used fire extinguishing agent, which is a dispersed system consisting of cells - air (gas) bubbles, separated by films of liquid containing a foaming agent [GOST R 50588-2012. Foaming agents for extinguishing fires. General technical requirements and test methods].

The ratio of the volumes of the gas and liquid phases (per unit volume) of the foam determines the structure and its properties. If the volume of the gas phase _Vg exceeds the liquid volume _Vg by no more than 10-20 times (low expansion foam), the foam cells filled with gas have a spherical shape. In such foams, gas bubbles are surrounded by liquid shells of relatively large thickness. Spherical foams are characterized by a high liquid content and, therefore, low stability. Therefore, they are classified as metastable (conditionally stable).

In unstable foams, the so-called Plateau effect is observed: the liquid phase is removed from the partitions, flowing out under the influence of gravity, and rapid coalescence occurs (from the Latin coalesce - merging, uniting) - the merging of touching gas bubbles. In foam, a gas bubble cannot move freely in either a vertical or horizontal plane. It is as if “sandwiched” by other bubbles adjacent to it.

With an increase in the V _g /V _l ratio, the thickness of the liquid film separating the gas volumes decreases, and the gas cavity loses its spherical shape. Medium expansion foams, in which the V _g / V _l ratio is several tens or even hundreds, have a multifaceted shape. Moreover, the shape of polyhedra can be different - triangular prisms, tetrahedrons, irregularly shaped parallelepipeds. During the aging process of the foam, the spherical shape of the cells becomes multifaceted. Multifaceted foams are characterized by a low liquid phase content and are characterized by high stability. In such foams, individual bubbles are brought together and separated by thin “stretched elastic films.” These films, due to their elasticity and a number of other factors, prevent the coalescence of gas bubbles. As the separating films become thinner, the bubbles come closer together, adjacent to each other and acquire a clear polyhedral shape [Bobkov S.A., Baburin A.V., Komrakov P.V. Physico-chemical foundations of the development and extinguishing of fires: textbook. manual / M.: Academy of the State Fire Service of the Ministry of Emergency Situations of Russia, 2014. - 210 pp.].

The main physical and chemical properties of the foam are:

Multiplicity - the ratio of the volume of foam to the volume of the foaming agent solution contained in the foam;

Dispersity – the degree of refinement of bubbles (size of bubbles);

Viscosity - the ability of foam to spread over a surface;

Resistance is the ability of foam to resist the process of destruction [ibid.].

Depending on the expansion ratio (K), foams are divided into four groups:

Foam emulsions, K < 3;

Low expansion foams, 3 < K < 20;

Medium expansion foam, 20 < K < 200;

High expansion foams, K > 200 [ Sharovarnikov A.F., Sharovarnikov S.A. Foaming agents and fire extinguishing foams. Composition, properties, application. M.: Pozhnauka, 2005. - 335 p.].

The dispersion of the foam is inversely proportional to the average diameter of the bubbles.

It is known that the higher the dispersion, the higher the foam resistance and fire extinguishing efficiency. The degree of foam dispersion largely depends on the conditions for its production, including the characteristics of the equipment. The expansion ratio and dispersion of the foam determine the insulating ability of the foam and its fluidity. [Bobkov S.A., Baburin A.V., Komrakov P.V. Physico-chemical foundations of the development and extinguishing of fires: textbook. manual / M.: Academy of the State Fire Service of the Ministry of Emergency Situations of Russia, 2014. - 210 pp.].

The fire extinguishing properties of foam are:

Insulating effect - preventing the entry of flammable vapors, gases or air into the combustion zone, causing the cessation of combustion;

The cooling effect is due to the presence of a significant amount of liquid in predominantly low expansion foam.

The cooling effect of foam is due to the water released from the foam.

The insulating effect is due to the formation of a foam layer that prevents oxygen from reaching the fire zone, including:

The separation effect consists of isolating the liquid from the vapor phase;

The displacement effect causing the isolation of the flammable substance from the air;

A blocking effect in which foam prevents the evaporation of a flammable liquid.

Low expansion foams (3 < K < 20) Due to the significant amount of water in the interbubble partitions (in the Plateau-Gibbs channels), they predominantly exhibit a cooling fire extinguishing effect, which is caused by the cooling effect of the foam itself and the water released from the foam.

Medium expansion foam (20 < K < 200) Due to the smaller amount of water in the interbubble partitions (in the Plateau-Gibbs channels), they predominantly exhibit an insulating fire extinguishing effect, caused by the creation of an atmosphere depleted in oxygen and saturated with water vapor above the combustion zone, which helps slow down and completely stop the combustion.

At the same time, due to the larger amount of water present in low-expansion foam and, accordingly, the greater density (weight per unit volume), low-expansion foam compared to medium-expansion foams can be supplied from longer distances, which significantly affects the safety of fire personnel during large-scale and explosive accidents with liquefied gases.

A characteristic distinctive feature of the proposed technical solutions is the production and use of hybrid water-air foam with an expansion ratio of 30 to 70 based on synthetic hydrocarbon foaming agents.

The authors in the applicant’s laboratory have experimentally established and theoretically substantiated that hybrid water-air foam with an expansion ratio of 30 to 70 is significantly different in its structure, viscosity, dispersity, rheological, thixotropic and other properties significant for explosion prevention and fire extinguishing from the known properties of foams of low and medium expansion by based on hydrocarbon and fluorine-containing foaming agents.

It was revealed that as a result of turbulent shockless mixing of low-expansion foam bubbles and medium-expansion foam bubbles in the hybrid foam, average-sized foam bubbles are formed, larger in comparison with low-expansion foam bubbles, but with thicker water-containing Plato channels compared to medium-expansion foams -Gibbs.

As experimentally established by the authors, the structure of a hybrid foam with a multiplicity of 30 to 70 with water-air bubbles unique in its structure and fire-extinguishing properties allows not only to better contain the high temperature of the flame without significant destruction of the volume of the hybrid foam itself, that is, to more effectively isolate the fire surface, but also to deliver jets of hybrid foam over significantly longer distances compared to jets of medium expansion foam or combined jets of low expansion and medium expansion foam.

The authors also experimentally established that when a hybrid foam with a multiplicity of 30 to 70 is exposed to the surface of a liquefied natural or hydrocarbon gas spill, a synergistic effect is manifested due to the simultaneous influence of several factors - cooling, dilution of atmospheric water vapor in the zone of evaporation and combustion of gas, thermal insulation and sharp reducing the concentration of gas and vapor of flammable liquids above the foam layer in the combustion zone until the rate of the chemical reaction decreases and the subsequent decrease in the flame temperature to the extinction temperature.

This is due to the average dispersion and thickening of the water-containing Gibbs-Plateau channels of the hybrid foam compared to low- and medium-expansion foams or compared to foam in combined low- and medium-expansion foam jets.

Full-scale tests of installations with the proposed grid cassette under the conditions of practical extinguishing of various real fires (Fig. 20-25) show a confident solution to the formulated problem (posed inventive task) and the real achievement of the required technical result - increasing the efficiency of extinguishing emergency transport, forest, industrial emergencies and other large-scale fires as a result of the creation, manufacture and practical use of the proposed installation, which is structurally simple, manufacturable and reliable in operation, and also proves:

- Simplicity and manufacturability of manufacturing, preparation for use, use, assembly/disassembly and repair of the proposed grid cassette for medium expansion foam generators;

- Simplicity and efficiency of operation;

- High reliability of operation for a long time (up to 7 years);

- Possibility of generating a jet of air-mechanical hybrid foam of medium expansion or sprayed water with high productivity and sufficient for safe work for fire personnel (40-55 m), which are most effective for extinguishing and preventing the spread of most fires;

- Possibility of manual and stationary use of installations with the proposed grid cassette with the possibility of manual and automatic control, the ability to create automatic oscillatory movements in various angular ranges, ensuring prompt, fast and uniform coverage of the entire surface of the fire with hybrid foam of medium expansion or sprayed water.

Comparative tests of the medium expansion foam generator GPS-600 (prototype) and the medium expansion foam generator type UKTP PURGA 30 produced by the applicant in the basic design with the proposed grid cassette showed the following main technical and operational parameters and indicators, listed in Table 1.

Table 1

The name of indicators GPS-600
according to GOST 50409-92
(prototype) Medium expansion foam generator type UKTP PURGA 30 with mesh cassette
according to the invention Water capacity (foaming agent aqueous solution) [l/s] 4.8-6 thirty Distance of mid-expansion foam jet [m] 10 45-50 Height of medium expansion foam jet [m] 5 20-27 Inlet pressure [MPa (kg/ ^cm2 )] 0.6 (6) 0.8-1.2 (8-12) Foam ratio 100 + 30 30 + 10 dimensions Length 610 1255 Width 350 625 Height, diameter of the body at the location where the grids are installed 310 590 Weight [kg] 4.45 40-50

As field tests have shown, the use of the proposed grid cassette in installations for combined fire extinguishing with air-mechanical hybrid foam of medium expansion or sprayed water, in comparison with known fire extinguishing agents with medium expansion foam, is most promising in the process of eliminating large-scale fires:

at enterprises of the fuel, chemical, oil refining industries;

at enterprises of the forestry, woodworking and pulp and paper industries, in forests and on agricultural land;

when extinguishing post-accident fires of air transport on the ground, accidents, disasters in non-railway, sea and river transport;

when neutralizing and disposing of potent toxic substances.

The use of the proposed grid cassette in medium-expansion foam generators makes it possible to implement new modern technologies for producing and supplying hybrid medium-expansion foam or sprayed water with increased range and spreading speed over the combustion surface, which allows:

reduce fire extinguishing time compared to traditional means in warehouses of ammunition and highly toxic substances;

significantly reduce the number of firemen directly involved in fire extinguishing;

reduce the risk to human health and life, since fire extinguishing can be carried out at a considerable distance from the burning object;

increase mobility and mechanization of the process of delivering water and foam to the combustion zone.

Taking into account the novelty of individual and aggregate essential features, the technical solution to the problem, the inventive step and the materiality of all general and particular features of the invention, disclosed in detail in the description and shown in the drawings, the technical feasibility and industrial applicability of the invention proven in the section “Implementation of the invention”, a confident solution to an actual problem , it has been proven that the required technical result has been confidently achieved in the implementation and use of the invention - increasing the efficiency of extinguishing emergency transport, forest, industrial and other fires through the creation, mass production and widespread practical use of structurally simple, technologically advanced and reliable in operation combined extinguishing with medium expansion foam or sprayed water with increased range.

This also proves that the proposed technical solutions to the current problem comply with all established patentability requirements for inventions, and also proves that the essence of the claimed invention is disclosed in the application documents with completeness sufficient for the implementation of the invention.

The analysis also shows that all the general and specific features of the invention are essential, since each of them is necessary, and together they are not only sufficient to achieve the purpose of the invention, but also allow the invention to be implemented industrially.

In addition, an analysis of the totality of essential features of a group of inventions and the single technical result achieved by using them shows the presence of a single inventive concept, a close and inextricable connection between the medium expansion foam generator grid cassette and the method of its manufacture. This makes it possible to combine inventions in one application, that is, to ensure compliance with the requirements of the unity of invention criterion.

Claims (47)

1. A grid cassette for installing combined fire extinguishing with medium-expansion air-mechanical foam or sprayed water, containing a housing, a grid cassette installed in the housing, a barrel and means for supplying a foam solution or water under pressure to the grid cassette and into the barrel, characterized by the fact that the grid cassette is made with a through hole in the grids to accommodate the barrel in it and contains coaxially installed one inside the other annular inner rim containing an annular holder with a through hole for placing the barrel in it, an intermediate rim and an outer rim and two grids located with a gap relative to each other, one of which, the first mesh, is fixed by its edges in the gap between the mating lateral surfaces of the annular inner and intermediate rims, and the other, the second mesh, is fixed with its edges in the gap between the mating side surfaces of the annular intermediate and outer rims, At the same time, the meshes have holes coaxial and commensurate with the through hole of the cage, with the edges of the meshes fixed to the frame by means of ring washers and screws. 2. Mesh cassette according to claim 1, characterized in that the inner and intermediate rims with fixed edges in the gap between their mating side surfaces with a mesh are installed one inside the other with interference and are additionally fixed to each other by spot welding. 3. Mesh cassette according to claim 1, characterized in that the intermediate and outer rims with fixed edges in the gap between their mating side surfaces with a mesh are coaxially installed one inside the other with interference and are additionally fixed to each other by spot welding. 4. Mesh cassette according to claim 1, characterized in that made with the ability to form, when a foaming agent solution is supplied under pressure, to a grid cassette and into the barrel of a combined air-mechanical foam of medium expansion, obtained as a result of turbulent shockless mixing in the process of joint co-movement of jets of air-mechanical foam of medium expansion formed on the grids and in contact with them from below a jet of low expansion air-mechanical foam formed in the barrel . 5. Mesh cassette according to claim 1, characterized in that contains annular inner, intermediate and outer rims with cylindrical side surfaces. 6. Mesh cassette according to claim 1, characterized in that The outer contour of the cassette contains semicircular side edges and a flat top and a flat bottom mating with them. 7. Mesh cassette according to claim 1, characterized in that an annular holder with a through hole for placing the barrel in it is installed and secured in the inner rim by means of flat ribs parallel to the direction of movement of the foam agent solution or water in the body. 8. A method for manufacturing a grid cassette for installing combined fire extinguishing with medium-expansion foam or sprayed water, containing a housing, a grid cassette installed in the housing, a barrel and means for supplying a foam solution or water under pressure to the grid cassette and into the barrel, characterized by the fact that a mesh cassette is made with a through hole in the mesh to accommodate the barrel, for which an annular inner rim is installed coaxially inside the other, containing an annular holder with a hole for the barrel, an annular intermediate rim and an annular outer rim, and placed on the indicated rims with a gap relative to each other mesh, one of which, the first mesh, is fixed with its edges in the gap between the mating side surfaces of the annular outer and intermediate rims, and the other, second mesh is fixed with its edges in the gap between the mating side surfaces of the annular intermediate and inner rims, in this case, holes are made in the meshes coaxially to the opening of the cage with fixation of the edges of the meshes on the frame using screws and ring washers. 9. A method for manufacturing a mesh cassette according to claim 8, characterized in that the first mesh is placed between an inner rim coaxially installed relative to each other, containing an annular holder with a hole for accommodating the barrel, and an intermediate rim, and by means of axial movement of the inner rim relative to the intermediate rim, the inner rim is pushed with tension inside the intermediate rim with the first mesh stretched onto the bottom of the inner rim and the edges of the first mesh fixed in the gap between the mating side surfaces of the intermediate rim and the inner rim, then the second mesh is placed on the top of the inner and intermediate rims aligned with each other with the first mesh stretched over the bottom of the inner rim, the outer rim is installed coaxially above them and by means of axial movement of the outer rim relative to the intermediate and inner rims aligned with each other, with the first mesh stretched over the bottom of the inner rim, the outer rim is pushed onto the intermediate and inner rims aligned with each other, with the second mesh stretched onto the top of the intermediate rim and fixing the edges of the second mesh in the gap between mating side surfaces of the outer and intermediate rims, after that, on the outer sides of the meshes, coaxially to the opening of the cage, ring washers with holes for the barrel are attached by means of screws, with the first and second meshes being fixed with screws between the ring washers and the cage, after which the mesh is cut along the contour of the holes of the ring washers and the cage to form a through hole for the barrel in the mesh cassette. 10. Method for manufacturing a mesh cassette according to claim 9, characterized by the fact that After stretching the first mesh onto the bottom of the inner rim, the edges of the first mesh protruding above the rims are cut off and the position of the inner and intermediate rims relative to each other is fixed by spot welding. 11. Method for manufacturing a mesh cassette according to claim 9, characterized by the fact that After stretching the second mesh onto the top of the intermediate rim, the edges of the second mesh protruding above the rims are cut off and the position of the outer and intermediate rims relative to each other is fixed by spot welding. 12. Method for manufacturing a mesh cassette according to claim 9, characterized by the fact that after stretching the second mesh onto the top of the intermediate rim, the edges of the second mesh protruding above the rims are folded along the side surface of the outer rim and the position of the outer and intermediate rims relative to each other is fixed by spot welding. 13. A method for manufacturing a mesh cassette according to claim 8, characterized in that a mesh cassette is manufactured according to any one of claims. 1-7.