RU2295369C2 - Collapsible protective structure and method for inflammable matter reservoir storage - Google Patents

Abstract

FIELD: fire prevention, containment or extinguishing specially adapted for highly-inflammable materials.

SUBSTANCE: composite protective structure comprises load-bearing case, heat-resistant heat insulation layer and protective-and-decorative facing. Load-bearing case consists of longitudinal and annular members and is closed with ropes connected to pole rings. Each annular member has upper and lower flanges. Lower flange is made as two semi-rings connected with each other. Upper flange is formed of two steel strips concentrically mounted on lower flange semi-rings by means of pins to create integral H-shaped semi-ring. Heat-resistant heat insulation layer includes outer fabric layers and intermediate heatproof one. One fabric layer surface facing fire is covered with swelling material. The heat-resistant heat insulation layer is formed as separate flat mats connected to the case. Reservoir storage method involves assembling collapsible structure around reservoir by installing longitudinal and annular members of load-bearing case and placing flat mats of heat-resistant heat insulation layer between the members, wherein the mats are retained by case ropes; mounting protective-and-decorative facing over the load-bearing case. Heat-resistant heat insulation layer includes outer fabric layers and intermediate heatproof layer. Surface of one outer fabric layer, which faces fire, is covered with swelling material. The swelling material may be converted into heat-resistant coked cellular material under fire action, wherein the coked cellular material has low heat conductivity and forms fire-barrier layer. Gap is left between protective-and-decorative facing and heat-resistant heat insulation layer. Gap thickness depends on swelling material type and is selected to provide full space filling with above fire-barrier layer without void space forming.

EFFECT: increased assembling and disassembling speed, as well as enhanced reliability and extended service life.

7 cl, 9 dwg

Description

The invention relates to fire-retardant fire fighting means and can be used for storage tanks for combustible gases and liquids at excessive internal pressure, liquefied gases at cryogenic temperatures installed in an open area under a canopy or indoors.

Various methods and structures are known for ground storage of flammable liquids. One of such systems is the design adopted by Pat. US 5564588 from 10/15/1996, in which the inner shell of the tank, having a cylindrical shape, is surrounded by an outer shell, while a refractory protective material is placed between the two shells. Moreover, in one embodiment, the known device is implemented in the form of three shells. The main disadvantage of such structures is the lack of the ability to dismantle the containment and, therefore, the additional cost of transporting a bulky structure if necessary to deliver it to remote areas. Known fire-retardant structures, made in the form of a large container, in which a tank with a flammable substance is placed, while on top of the container is closed by a removable lid (US Pat. US 5884709, from 03.23.1999). Transporting such containers is also time consuming.

In addition, various embodiments of collapsible heat-shielding constructions are known, which are intended primarily for shipping containers with substances whose temperature differs significantly from ambient temperature. Such structures are made, for example, in the form of heat-shielding panels mounted by means of longitudinal and transverse elements around the tank and covered with an external cladding (see, for example, US 3800970, 04/02/1974 and US 4050609, 09/27/1977). However, such devices are not intended for ground storage of tanks with flammable substances, and therefore do not contain fireproof layers.

The task underlying the proposed technical solution is the creation of a fireproof collapsible design and a method for storing tanks with flammable substances, ensuring quick assembly and disassembly, and at the same time having high reliability and durability.

The problem is solved in the proposed collapsible protective structure for storing tanks with flammable substances, containing a supporting frame, heat-resistant heat-insulating layer and a protective and decorative lining, while the supporting frame consists of longitudinal and ring elements, and is closed by cables connected to pole rings, each the annular element consists of upper and lower shelves, the lower of which is two half rings interconnected, and the upper is made of two steel strips, on-center mounted on the half rings of the lower shelf by means of pins to form a single I-half half-ring, and the heat-resistant heat-insulating layer consists of external woven layers, on the surface of one of which, facing the fire effect, a layer of intumescent material is applied, and an intermediate heat-resistant layer and is made in the form of fixed in frame flat mats.

It is advisable that the flat mats abut against the studs with guaranteed compression, which is achieved by choosing the width of the elements of the heat-resistant heat-insulating layer, and be fixed by ropes of the supporting frame.

Preferably, the flat mats have a decreasing thickness on two opposite edges, which is formed by sections having a wedge-shaped cross section, and at one end of the mat, the thickness decreases from the inner surface to the outer, and at the opposite end, from the outer surface to the inner, so that the edges of adjacent the mats are overlapped at the installation sites of the longitudinal elements of the frame.

The studs are preferably mounted with an inclination relative to the radius of the half rings of the annular element.

Four recesses with two grooves for installing longitudinal elements can be made in the upper shelf of the half-ring of the annular element, and each longitudinal element is made in the form of a wave-like bent profile and has two protrusions in section corresponding to the indicated grooves of the recess.

Sheets of protective and decorative lining and mats of a heat-resistant heat-insulating layer have cutouts for protruding elements of the tank.

The problem is also solved in the proposed method for storing tanks with flammable substances, which consists in installing a collapsible structure around the tank, in which longitudinal and annular elements of the supporting frame are installed, between which flat mats of a heat-resistant heat-insulating layer are placed, which are fixed by the frame cables, and then installed on top of the frame the supporting frame of the protective and decorative cladding, and the heat-resistant heat-insulating layer is made of an intermediate heat-resistant layer and external woven layers, on the surface of one of which, facing the fire effect, a layer of intumescent material is applied, which, when exposed to fire, is converted into a heat-resistant low-heat foam foam coke, forming a fire-resistant layer, while a gap is left between the protective and decorative lining and the heat-resistant heat-insulating layer, the size of which depending on the type of intumescent material, it is determined on the basis of ensuring that the specified gap is completely filled with the fire-resistant layer formed in it without azovaniya cavities.

The invention is illustrated by drawings, which represent:

figure 1 and 2 is a General view of a collapsible protective structure for storage of tanks; figure 3 is a cross-sectional shape of the longitudinal elements of the supporting frame; figure 4 and 6 - the design of the ring elements of the supporting frame; figure 5 is a method of attaching cables fixing a heat-resistant heat-insulating layer of the bottoms; Fig.7 is a cross section of the wall of the tank with a protective structure along the generatrix of the shell in the initial state; on Fig - section of the wall of the tank with a protective structure along the generatrix of the shell when the fire impact on the outer surface of the protective and decorative cladding; figure 9 - the design of the holes in the protective and decorative cladding.

The following is a more detailed description of the invention with reference to the position of the drawings.

The main elements of a collapsible protective structure for storage of tanks are:

a) heat-resistant insulating layer 3 with intumescent (thermally expanding) coating 22;

b) supporting frame 2;

c) protective and decorative cladding 4.

Protective and decorative cladding 4 has the following functions:

a) protecting the fibrous materials of the heat-resistant heat-insulating layer 3 from atmospheric precipitation (water penetration);

b) reflection of solar radiation and thermal radiation of the flame;

c) protect the heat-resistant heat-insulating layer from mechanical damage;

d) protection of the foam coke 23, which is formed during thermal exposure to the intumescent coating of the heat-resistant heat-insulating layer from erosion damage under the influence of wind, convective flows or turbulent vortices arising in the flame;

d) giving the design a proper appearance.

In the proposed protective structure, a closed-type supporting frame is used, consisting of longitudinal elements 1; ring elements 2, cables 5 and pole rings 6.

The ring elements 2 are formed by two half rings of an I-beam cross section. The lower shelf 11 of the annular element is bent from a steel strip with a section size of 2 × 20 mm in the form of a half ring with a radius corresponding to the outer surface of the shell of the tank. The upper shelf 9 of the annular element is made of a steel strip with a cross-sectional dimension of 0.8 × 80 mm. The top shelf is mounted concentrically on the bottom with a uniform gap equal to the design thickness of the heat-resistant heat-insulating layer. The connection of the lower and upper shelves of the annular element with each other and, thus, the formation of a single I-beam half-ring is carried out using studs 10 with a diameter of 03 mm The studs 10 are oriented with an inclination relative to the radius of the annular element. In the upper shelf of the semicircle of the annular element there are four recesses with two grooves for installing and securing the longitudinal elements. The size of the recess is 10 mm, which eliminates the elevation of the surface of the longitudinal element above the outer dimension of the annular element. The studs are installed in pairs in the region of the recesses under the longitudinal elements with a mirror orientation, which ensures the stiffness of the ring element when shifted in the tangential direction. In addition, there are two studs located in the connection areas of the half rings (at both ends of the upper shelf), the arrangement of which is also mirror.

Ring elements are installed on the surface of the shell with a pitch of 400 ... 800 mm. The connection of two half rings into a single annular element mounted on the surface of the shell is carried out by means of two bolts 7 and nuts 8, tightening the lower shelves 11 for free edges.

Longitudinal elements are slats with overall dimensions of a cross section 10 × 100 mm wide. They are made of steel sheet with a thickness of 0.5-1 mm in the form of a wavy curved profile and have two protrusions in cross section corresponding to the indicated grooves of the recess.

The cross-sectional shape of the longitudinal element is shown in figure 3.

Longitudinal elements are installed along the generatrix of the shell in the recesses in the upper shelves of the annular elements and are fixed using screws with nuts or self-tapping screws. In the embodiment of fastening the longitudinal elements to the ring elements with screws and nuts, holes in the form of grooves are provided in both structural elements of the supporting frame. The location of the grooves in the longitudinal elements is longitudinal, and in the ring elements - perpendicular to them, which facilitates the collection of this design.

The longitudinal elements are located in the axial direction with a step close to uniform, the value of which is in the range of 400-800 mm.

The frame is closed on the surface of the heat-resistant heat-insulating layer of the bottoms using steel cables 5 with a diameter of 1-4 mm. As the closing elements of the frame, rings 6 are used, which together with the cables 5 fix the heat-resistant heat-insulating layer of the bottoms. Pole rings can be made of a steel bar with a diameter of 5-8 mm or of a steel cable with a diameter of 2-5 mm, the ends of which are fastened with a clamp 12. The cables are fastened with a loop around the pin or passed through a hole in the pole ring using screw clamps 12 according to GOST 13186-67 or similar other standards (180, AK81, VTK).

In the heat-resistant heat-insulating layer of the shell and the bottoms on the outer layer facing the fire effect, an intumescent (thermally expanding) coating is applied, applied to the glass fabric.

The heat-resistant heat-insulating layer of the shell is made of flat mats with cutouts for protruding elements of the tank, such as pipes 20, manhole 19, supports 21. They are installed between the ring elements. Their edges abut the studs 10 with guaranteed preload, and the free ends are connected with an overlap over a length of 150-250 mm. Guaranteed preloading of the edges to the studs is achieved by choosing the width of the elements of the heat-resistant heat-insulating layer of the shell, the value of which exceeds the distance between the ring elements by 5-10%. Depending on the size of the outer diameter of the shell, one or two mats can be installed between the two ring elements. In the overlap zone, the ends of the mats are fastened together. Silica tapes mounted on the mat surface from the side of the protected object serve for their fastening. Tapes located at opposite ends are connected by tying or by means of locks mounted on them such as a carbine with a loop (preliminary fixation).

In overlaps, the thickness and structure of the mat is the same as in continuous sections. This is achieved by the fact that at both ends of the mat mounted on the shell, at a distance of 150-250 mm, the thickness linearly disappears. Moreover, at one end, a decrease in thickness occurs from the inner surface to the outer, and at the opposite end, from the outer surface to the inner.

The final fixation of all mats mounted on the shell is carried out using a steel cable 5. This cable is installed by lacing, around the diagonally located (offset by a pitch of longitudinal elements) studs of adjacent ring elements, so that reactive forces at the contact points of the cable with the studs are caused by the first pulling force is directed towards the surface of the shell, and thus the force causes additional compression of the mats to the surface of the shell.

The shape of the mats installed on the tank bottoms corresponds to the shape of the surface to be protected, and when installed they do not form closed cavities.

The mats mounted on the bottoms of the tank are fixed with the help of a pole ring 6 and steel cables 5 extending from it.

Elements of the heat-resistant heat-insulating layer of fire protection of the shell and bottoms (mats) consist of outer woven layers 17, 18, on the surface of one of which, closest to the fire 24, a layer of intumescent composition 22 and an intermediate heat-resistant layer 16 are applied.

The outer layers are made of fiberglass with a surface density of 200-600 g / m, and the intermediate heat-resistant one is made of piercing material based on basalt fibers with a diameter of 5-25 μm and a density of 80-120 kg / m ³ . The intumescent coating layer thickness is 1-2 mm.

The layers are bonded to each other through a cross-sectional point cross stitch made of glass or silica threads.

During fire exposure, the intumescent coating 22 is converted into a heat-resistant low-heat foam coke 23, forming a fire-resistant layer, the thickness of which can exceed the thickness of the original coating by 20-50 times and is controlled by the distance to the protective and decorative lining 4.

The thickness of the heat-resistant layer is in the range of 20-60 mm, and fire-resistant - 15-50 mm.

The gap between the surface of the intumescent coating and the protective and decorative lining is determined by the distance between the shelves 9 and 11 of the annular element 2 and the thickness of the mats in the initial state.

To form a protective and decorative lining 4, which protects the heat-resistant heat-insulating layer of the shell and the bottoms from atmospheric precipitation and mechanical damage, galvanized steel sheets with a thickness of 0.5-0.8 mm are used. Elements 14 are cut from the sheets, having the required overall dimensions and cutouts for nozzles, manhole, supports, etc. In addition, holes are provided in the upper part of the lining connecting the cavity bounded by the surfaces of the intumescent coating and the protective-decorative lining with the atmosphere. The holes are protected from atmospheric precipitation (Fig.9).

Elements of protective and decorative facing of the shell and bottoms are attached to the upper shelf of the ring elements using self-tapping screws 13.

Neighboring elements are installed with an overlap. Sealant 15 is used to eliminate gaps in the overlapping places. The shape of the elements of the weather-resistant layer of the bottoms can be either flat or correspond to the shape of the surface to be protected. In the case when the protective and decorative lining of the bottoms is flat, the formed cavity between it and the surface of the heat-resistant heat-insulating layer is filled with superthin basalt fiber.

The shape of the elements of the protective and decorative lining of the bottoms can be either flat or correspond to the shape of the surface to be protected. A gap is maintained between the surface of the intumescent coating and the lining, the minimum value of which (with a flat version) corresponds to the difference in the distance between the shelves of the ring elements and the thickness of the mats installed on the bottom.

Claims (7)

1. A collapsible protective structure for storing tanks with flammable substances, containing a supporting frame, a heat-resistant insulating layer and a protective and decorative lining, while the supporting frame consists of longitudinal and ring elements and is closed by cables connected to the pole rings, and each ring element consists of the upper and lower shelves, the lower of which is two interconnected half rings, and the upper is made of two steel strips concentrically mounted on the half rings the lower shelf by means of pins to form a single I-half half-ring, and the heat-resistant heat-insulating layer consists of outer woven layers, on the surface of one of which, facing the fire effect, a layer of intumescent material and an intermediate heat-resistant layer are applied and made in the form of flat mats fixed in the frame. 2. The construction according to claim 1, in which the flat mats abut against the studs with guaranteed compression, which is achieved by choosing the width of the elements of the heat-resistant heat-insulating layer, and are fixed by cables of the supporting frame. 3. The construction according to claim 1, in which the flat mats have a decreasing thickness on two opposite edges, which is formed by sections having a wedge-shaped cross section, and at one end of the mat, the thickness decreases from the inner surface to the outer, and from the opposite - from the outer surface to the inside, so that the edges of adjacent mats are overlapped at the installation sites of the longitudinal elements of the frame. 4. The design according to claim 1, in which the studs are installed with an inclination relative to the radius of the half rings of the annular element. 5. The construction according to claim 1, in which four recesses with two grooves for installing longitudinal elements are made in the upper shelf of the half-ring of the annular element, each longitudinal element is made in the form of a wavy curved profile and has two protrusions in section corresponding to the indicated grooves of the recess. 6. The construction according to claim 1, in which the sheets of protective and decorative cladding and mats of the heat-resistant heat-insulating layer have cutouts for the protruding elements of the tank. 7. A method of storing tanks with flammable substances, which consists in installing a collapsible structure around the tank, in which the longitudinal and annular elements of the supporting frame are installed, between which flat mats of a heat-resistant heat-insulating layer are placed, which are fixed by the cables of the frame, and then installed on top of the supporting frame is a protective decorative lining, and the heat-resistant heat-insulating layer is made of an intermediate heat-resistant layer and the outer woven layers, on the surface of one of the In the case of fire, a layer of intumescent material is applied, which, when exposed to fire, is converted into a heat-resistant low-heat-conductive foam coke, forming a fire-resistant layer, while a gap is left between the protective and decorative lining and the heat-resistant heat-insulating layer, the value of which is determined based on the type of intumescent material from ensuring complete filling of the specified gap with the fire-resistant layer formed in it without the formation of cavities.

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