EA041086B1 - REINFORCED REMOVABLE THERMAL INSULATION (ASTI) - Google Patents

Description

The invention relates to thermal insulation technology, and more specifically to thermal insulation structures of pipelines and cylindrical vessels.

From the prior art, a prefabricated heat-insulating structure is known, containing, tightly enclosing the pipeline, a cylindrical shell of sections arranged in series along its length and interconnected, each of which is made of joined and interconnected N-heat-insulating elements with a cross section in the form of an annular sector (see patent RU-U1 - No. 40433,2004).

Known block removable thermal insulation (hereinafter - BSTI) (prototype), which is a box made of steel. The cavity of the box is filled with heat-insulating material. Mats made of glass or basalt staple fiber are used as heat-insulating material. From movements inside the box, the heat-insulating material is fixed with the help of special pins and clips. After laying the heat-insulating material, the box is closed with pocked stainless foil, which is welded on the inside of the block. All elements of the block are fastened together by contact welding. The blocks have the ability to repeat the surface of the heat-insulated equipment. Fastening of the BTI on equipment and pipelines is carried out using special tension locks, pre-installed on blocks of about 60%, and the remaining 40% of the locks are fastened by welding at the installation of the BTI (http://aozio.ru/nuclear/oborudovanie-dlyaatomnoj-energetiki/ blochnaya-syomnaya-teplovaya-izolyacziya.html).

The disadvantage is that the thick-walled steel of the BSTI box (1.0 and 0.5 mm), due to the strength characteristics due to the large dimensions of the blocks and the fastening of a large number of tight tension locks on their surface, leads to the irrational use of steel and heat-insulating material.

The ratio of the weight of the heat-insulating material to the weight of the BSTI blocks is 31.3% (19 tons - heat-insulating material and 41.7 tons - steel), which leads to the conclusion that the presence of steel (68.7%) in the heat-insulating structure of the blocks is not rational.

The presence of tight tension locks on the surface of the blocks leads to a large thickness of the box steel and to the occurrence of moments of forces that tend to unscrew the blocks due to bending moments and open the gaps of the surfaces of the blocks facing the heat-insulated surface, which can lead to an additional increase in temperature and deterioration of the thermal insulation properties of the BST.

The invention is aimed at solving the problem of reducing the weight of stainless steel heat-insulating blocks and creating guaranteed minimum gaps on the side surfaces of the blocks that shield the heat emissions of equipment.

The problem is solved due to the fact that the reinforced removable thermal insulation (hereinafter referred to as ASTI) contains heat-insulating blocks placed close to each other on the outer surface of the heat-insulated equipment, joined together by longitudinal side walls and including boxes made of stainless steel and filled with heat-insulating material, while the structure of the box is made in the form of a joint consisting of a strong reinforcing frame lattice and a thin-walled stainless steel facing sheet, forming an ASTI block, while the reinforcing frame lattice can be made with a three-, four-, five- and hexagonal cell, the ASTI blocks are fastened together with the help of locks-latches installed at the corner intersections of the outer and inner bases, mating ASTI blocks to each other, and consisting of portable grips and fixed hook chambers placed inside ASTI blocks, the grips are made in the form of rounded flexible and elastic plates with the possibility of their compression, each hook is made in the form of stamped walls, fixed to the frame of the block with the help of stiffeners and a stainless plate, the walls of the hook form sections with plane e, mutually in contact with the surface of the elastic plates of the grip with a rounding, placed coaxially with the line of the joints of the corners side walls, the grippers are interconnected by an annular spring fastened to the elastic gripper plates and connecting them symmetrically with respect to the gripper symmetry axis to form a compensated flexible tension.

The reinforcing frame grating is made of rods with a diameter of 0.2-0.5 mm, and is made of rods of round cross section or rods of another profile equivalent in strength to them.

The connection of the box is additionally provided with stamped corrugated washers with grooves with a narrowing of the inlet part for joining with the intersections of the bars of the reinforcing frame lattice, which, at the same time, is fastened with shelves of corrugated washers to a thin-walled stainless steel sheet by contact welding.

The reinforcing frame grating is connected to a thin-walled stainless steel cladding sheet by means of electric welding without corrugated washers.

As part of the reinforcing frame lattice, there is one reinforced bar profile, located with a linear dimension parallel to the axis of the cylindrical surface of the heat-insulated equipment and connected by a contact method to the second bar of the reinforcing frame lattice, which makes it possible to unify the assembly of the supporting frames of ASTI blocks for thermal insulation of the surface of any curvature of the heat-insulated equipment.

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The proposed design of the assembly of the lock-latch with an annular spring makes it possible to ensure reliable contact of the surfaces of the ASTI blocks due to the guaranteed tightness in the inaccessible inner part of the contacting side faces of the blocks to ensure their tight fit with each other. For further clarity, we define that the inaccessible base of the block facing the heat-insulated surface is taken as the internal base of the heat-insulating block, and the colder, serviced base of the heat-insulating block is considered the outer base.

The use of locks-latches in heat-insulating blocks allows saving the weight of stainless metal of thermal insulation, increasing the strength of heat-insulating blocks, maximally eliminating the opening of thermal gaps between the side faces of heat-insulating blocks from the side of inaccessible internal bases of thermal insulation, as well as increasing heat-insulating reliability achieved by reliable contact of the side faces of heat-insulating blocks due to the use of guaranteed tightness between the hooks of heat-insulating blocks and the grips of latch locks with a guaranteed tightness, simplifies the design and reduces the number of tension locks by half.

Placement of hooks in the corners at the intersection of the side faces of the ASTI block in the factory eliminates numerous fitting work and welding ~ 6400 tension locks on the surface of the ASTI blocks, installed individually in place during assembly and assembly work on the equipment.

When placing the hooks inside the ASTI heat-insulating blocks, there is no deformation of the hooks during the transportation of removable heat-insulating blocks in cramped conditions during the initial installation, dismantling and during operation, as well as during scheduled inspections and control of the metal of heat-exchange surfaces of nuclear power plants.

The invention is illustrated by drawings.

In FIG. 1 shows the components of the frame, made of stainless grating with a square cell.

In FIG. 2 shows the component parts of the frame with corrugated washers installed at the crosshairs of the lattice.

In FIG. 3 shows the frame parts of the heat-insulating block, lined with a thin-walled stainless steel shell with an allowance along the perimeter, and welded to the shelves of corrugated washers by contact welding.

In FIG. 4 shows an ASTI hollow block assembled and welded by resistance welding on the allowances of a thin-walled stainless steel shell without thermal insulation and a final internal base made of stainless steel blistering sheet.

In FIG. 5 shows a view of the hollow block ASTI from the side of the inner base.

In FIG. 6 shows a corrugated washer.

In FIG. 7 shows a three-dimensional view of a corrugated washer.

In FIG. 8 shows the capture of the lock-latch

In FIG. 9 shows a three-dimensional view of the catch of the lock-latch.

In FIG. 10 shows a three-dimensional view of the latch hook mounted on a triangular plate.

In FIG. 11 shows a top view of a hook attached to an ASTI block.

In FIG. 12 shows the docking of ASTI heat-insulating blocks and fixing them with a latch-lock.

In FIG. 13 shows the hooks mounted on the blocks.

In FIG. 14 shows the frame of the block, made of a grating with profile reinforcement of one bar and the second bar-strip, connected by a contact method.

ASTI contains heat-insulating blocks placed close to each other on the outer surface of the heat-insulating equipment, joined together by longitudinal side walls. The blocks include boxes made of stainless steel and filled with heat-insulating material. The design of the box is made in the form of a joint consisting of a strong reinforcing frame lattice 1 with side walls 2 and front walls 3 (Fig. 1), made of rods 20 fixed to each other (Fig. 2) of a round or equivalent in strength bars of a different profile section, thin-walled stainless facing sheet 5 (Fig. 4), from stainless stamped corrugated washer 4 (Fig. 2, 5) with shelves 7 for contact welding, gutters 8 with a slight narrowing of the inlet for docking with crossroads of bars of the reinforcing frame lattice 1, which shelves corrugated washers 4 (Fig. 6, 7) fastened with a thin-walled stainless steel facing sheet 5 with a thickness of 0.1-0.4 mm (Fig. 3) using contact welding, forming an ASTI block.

The reinforcing frame lattice 1 (Fig. 1) in the initial state for convenience and clarity of the image is selected with a square cell and a round section of the rod, completely flat on both sides. However, it can be made with three, five, hexagonal and rectangular cells and different sections of the rod 20 (Fig. 2). It is preferable to use a grating with a round bar section.

The stainless steel reinforcing frame grating can be pre-bonded with the stainless steel shell by electric welding without knurled washers.

The bars of the reinforcing frame lattice 20 (Fig. 2) can be made of a material different from stainless steel and of various profiles, but not inferior in strength to stainless steel bars and connected to a stainless facing sheet using corrugated washers.

Corrugated washers 4, made by stamping, have a design that allows, when assembling them with cross nodes of the reinforcing frame lattice, to be fixed and installed with shelves 7 (Fig. 6) flush with the plane of the lattice. To do this, the entrance part of the gutters 8 has a slight narrowing. Shelves 7 are used for resistance welding of corrugated washers 4 with a thin-walled steel shell of the block. With a reinforcing frame lattice of small curvature, which is typical for thermal insulation of equipment of large diameters, corrugated washers are almost flat, while with small diameters of heat-insulated pipelines, when stamping corrugated washers, the curvature of the pipeline surface should be taken into account.

After mounting the corrugated washers 4 on the reinforcing frame lattice 1, the lattice and the stainless metal thin-walled steel shell 6 are bent according to the template. When this stainless metal thin-walled steel shell 6 is selected with the appropriate allowance around the perimeter. With the help of a bar with a channel profile, a brand and other profiles 21 (Fig. 14) connected to a bar - strip 22, the lattice is bent with minimal effort and the bars are connected using profile corrugated washers 4 with the shape of grooves 8 corresponding to the shape of the reinforcing frame lattice 1, which makes it possible to assemble the supporting frame of the ASTI block in a unified manner for thermal insulation of any curvature of the equipment surface without the use of additional structural parts.

The frame reinforcing lattice 1 can be made of a reinforced bar profile of various modifications. In the manufacture of a lattice with a corresponding step d of the reinforced profile of the rod 21 (Fig. 14) and the rod-strip 22 and the linear dimensions of the lattice l1 and l ₂ , where l ₁ is the height of the radial rod of the front side surface of the frame of the block, coinciding with the thickness of the heat-insulating layer of the block minus two thicknesses of facing steel, and l ₂ is the linear length of the ASTI block, parallel to the axis of the insulated body or pipeline. Having made a cut of the reinforcing profile shelves (channel, brand, etc.) at the border of sizes l1 and l ₂ , bending the profile strip at this border at an angle of 90 ° and connecting the cut profile shelves together by contact method, a preliminary blank for the frontal frame is obtained side surface of the block. To obtain the final front surface, the lattice strips 22 are cut in an appropriate way, connecting the radial blanks of the reinforced rod 21, the lattice is bent along the outer surface in accordance with the required curvature of the ASTI block, and the cut lattice strips are fixed to each other by contact, thus obtaining the front side surface block frame. Do the same with the front side surface on the other side of the block. By bending the frame lattice strips at the required angle, two adjacent side surfaces are obtained, adjoining the front side surfaces, which are then contact-connected to each other, fixing the entire side surface of the block frame.

The design of the reinforcing frame lattice 1 with bars 21 of different profiles, which makes it possible to carry out the supporting frame of the ASTI block of any curvature, leaving the design cells of the outer surface of the frame constant and the same in pitch and size, reducing, conservatively, in margin of safety, the step and dimensions of the cell of the inner surface of the frame block ASTI. This design creates a predetermined unification of the supporting frame of almost any ASTI block.

The ASTI blocks are fastened together with the help of locks-latches installed at the corner intersections of the outer and inner bases of the mating ASTI blocks and consisting of portable grippers 10 and fixed chambers of hooks 12, placed inside the ASTI blocks.

The lock - latch consists of a fixed part - a hook 12 and a portable part - a grip 10 (Fig. 8, 10). The latch lock is installed at the intersections of ASTI blocks, that is, one lock per intersection or one lock per one ASTI block.

The hook 12 (Fig. 10) is made in the form of stamped walls and with the help of stiffeners 13 and argon-arc welding is attached to the triangular plate 14 perpendicular to its bisector 15 of the right angle. Then, before filling the hollow ASTI block with heat-insulating material, using argon-arc welding, the hook 12 is attached to the frame of the block. It should be noted that, with small dimensions of the hook (25 mm in height and 20x30 mm in width and length), after its installation from above, it is necessary to install additional local thermal insulation.

Dimension a is the distance along the bisector of the angle from the lower joint block and is measured from the top of the angle to the near wall of the chamber 19 of the hook 12, with which the surface of the elastic wall of the grip 18 interacts (Fig. 8). This distance is a constant dimension.

Dimension b is the distance from the axis of symmetry of the grips 17 to the surface of the elastic wall of the grip 18, which interacts with the wall of the openings of the chamber 19 of the hook 12. This is a changing size that occurs due to the torsion of the section and the elastic tension of the annular spring 9.

Dimension c is the distance of guaranteed tightness, considered in statics before the interaction (docking) of the grip and the hook.

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Size c = a-b - guaranteed tightness, compensated in the process of interaction (docking) of the grip 10 and the hook 12 due to the deformation of the annular spring 9, forming a flexible feedback during thermal expansion or cooling of the heat-insulated body. Dimension c is obtained by joining as a result of sliding of the grip petals 10 (Fig. 8) with a rounding of radius R along the inclined plane e of the hook chamber and the interaction of the surface of the elastic wall of the grip with the wall of the hook chamber.

An annular spring 9 (Fig. 8), passing through the bases of the grips and serving to tension the grips and create a stable rigidity of the grips assembly with the spring, can be made flat, cylindrical or other shape, with or without a connector. In the normal mode, the tension of the grip occurs due to the resulting elastic deformations: bending of the grip plates, elastic torsion and straightening of the arcs of the one-piece spring between the bases of the grip of the ASTI blocks, since the chord is always less than the length of the arc of the circle connecting the chord. In the design of a latch-latch with three grips in the limit tension, the one-piece spring takes the form of a triangle, with four grips the shape of a square or rectangle, and so on.

Due to the compensated guaranteed flexible tightness, tight contact and fixation of the side faces of the ASTI heat-insulating blocks is ensured, forming a flexible feedback during temperature fluctuations of the heat-insulated surface of the equipment.

The angle of inclination of the plane e of the hook chamber depends on the angle of coverage of the surface of the ASTI block of the heat-insulating surface.

The hook chamber 12 (Fig. 10) has openings 19, passing through which, when docking, the petals 10 and the surface of the elastic wall 18 of the grip fix the movable hook relative to the first ASTI block. The movable grip is in contact with the bases of the heat-insulated surface of the body. After its docking with the hook, a 3-5 mm isothermal gap appears between the heat-insulated body and ASTI blocks, excluding local thermal stresses on the surface of the body. The second block, docked with the capture of the same lock-latch, repeats the previous operation. In the same way, the third and fourth blocks are joined with one latch lock. The fifth, sixth and so on ASTI blocks are identically joined. Closing along the perimeter of the cylindrical part of the pipeline or cylindrical apparatus, ASTI blocks form a closed chain of blocks, self-retaining them on a heat-insulated surface.

If a latch-latch is installed from the outer base of the ASTI blocks, that is, the latch-latch moves to the removable heat-insulating blocks to fix them, then the inclined plane e at the hook chamber becomes vertical. In this case, all considerations regarding the dimensions a and b, as well as the dimension c, remain the same.

After the production of the structure, the installation of the hook 12 and resistance welding on the allowances of the facing sheet, the hollow block ASTI 16 (Fig. 11) is filled with heat-insulating material, and then a stainless steel sheet is fixed on the allowances using resistance welding.

For example, the calculation of a reinforced frame lattice with a bar diameter of 2 mm (for comparison, the thickness of the stainless steel of the BSTI box is 1 mm) and a square cell pitch of 60 mm, a steel shell 0.2 mm thick, corrugated washers 0.5 mm thick, 15 mm in diameter blocks of ASTI of the following data are obtained.

The thickness of the stainless thin-walled steel shell of the BSTI is equal to

Si=kiD Vp/[6]

The thickness of the stainless thin-walled steel shell ASTI is equal to

S ₂ =k ₂ dVP/[6] _ k _± D “ k ₂ djP/[a] “ k ₂ d

S _± k ₂ d ⁼ k _± D ⁼

1.0x0.56x60 0.43x1000

0.078 mm where d is the cell pitch of the frame reinforcing lattice of the ASTI block, D is the maximum size of the shell of the BSTI block; S1 is the thickness of the thin-walled stainless steel shell BTI; S ₂ is the thickness of the thin-walled stainless steel shell of the ASTI; k1 - coefficient taking into account the method of fastening the edge of the box plate BST*, k ₂ - coefficient taking into account the method of fastening the edge of the cladding plate ASTI*.

*(Standards for calculating the strength of equipment and pipelines of nuclear power plants. PNAE G7-002-86. Moscow, 1989).

The formulas for calculating the thickness of the ASTI and BSTI shells are taken conservatively as for a flat bottom operating under low external pressure, which most realistically reflects the geometry and operating modes of the blocks;

Taking into account the thickness of the outer base of the BST equal to S1=1.0 mm, k1=0.56, D=1000 mm, k ₂ =0.43, t=60 mm, we obtain a preliminary equal-strength thickness of the stainless thin-walled steel shell S ₂ = 0.078 mm. Assuming the thickness of the stainless steel shell is 0.2 mm, we obtain a margin of safety

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Claims (6)

equal to 2.56, that is, the shell of the ASTI block is 2.56 times stronger than the shell of the BTI. According to the calculations of bending moments, the safety factor is even higher, since the linear dimensions in the formulas are included in square ratios. When calculating the weight of ASTI blocks, a reinforcing steel lattice with a square cell with a step 60 mm and a lattice bar diameter of 2 mm. The calculated weight of stainless steel of BSTI blocks is 41.7 tons. The calculated weight of stainless steel of ASTI blocks is 15.0 tons. Savings of stainless steel is 26.7 tons. The weight of the thermal insulation material in both versions is 19.0 tons. The relative percentage of the share of heat-insulating material in the BSTI blocks is 31.3%, the share of stainless metal is 68.7%. The relative percentage of the share of heat-insulating material in ASTI blocks is 55.9%, the share of stainless metal is 44.1%. The savings in stainless steel is 64.0%. The estimated cost of ASTI blocks will be at least two times cheaper. Taking into account the use of corrugated steel washers for fastening the reinforcing frame lattice with a thin-walled stainless steel shell using contact welding, it is possible to successfully replace the steel of the reinforcing lattice rod with a non-metallic material that is larger in cross section, but equal in cross section strength, which will lead to even greater savings in stainless steel . CLAIM 1. Reinforced removable thermal insulation (ASTI), containing heat-insulating blocks placed close to each other on the outer surface of the heat-insulated equipment, docked together by longitudinal side walls and including boxes made of stainless steel and filled with heat-insulating material, characterized in that the design of the box is made in the form of a joint consisting of a strong reinforcing frame lattice and a thin-walled stainless steel facing sheet, forming an ASTI block, while the reinforcing frame lattice can be made with a three-, four-, five- and hexagonal cell, the ASTI blocks are fastened together with locks - latches installed at the corner intersections of the outer and inner bases, mating with each other ASTI blocks, and consisting of portable grips and fixed hook chambers placed inside ASTI blocks, the grips are made in the form of rounded flexible and elastic plates with the possibility of their compression, each the hook is made in the form of stamped walls fixed to the frame of the block with the help of stiffeners and a stainless plate, the walls of the hook form sections with plane e, mutually contacting when docked with the surface of the elastic plates of the gripper with a rounding, placed coaxially with the line of joints of the corners of the side walls, the grippers are connected between an annular spring fastened to the elastic plates of the grip and connecting them symmetrically with respect to the axis of symmetry of the grips with the formation of a compensated flexible tension. 2. Reinforced removable thermal insulation (ASTI) according to claim 1, characterized in that the reinforcing frame lattice is made of bars with a diameter of 0.2-0.5 mm. 3. Reinforced removable thermal insulation (ASTI) according to claim 1, characterized in that the reinforcing frame lattice is made of rods of round cross section or rods of another profile equivalent in strength to them. 4. Reinforced removable thermal insulation (ASTI) according to claim 1, characterized in that the connection of the box is additionally equipped with stamped corrugated washers with grooves with a narrowing of the inlet part for joining with crossroads of bars of the reinforcing frame lattice, which, at the same time, is fastened with shelves of corrugated washers to thin-walled stainless steel shell by contact welding. 5. Reinforced removable thermal insulation (ASTI) according to claim 1, characterized in that the reinforcing frame lattice is connected to a thin-walled stainless steel facing sheet by electric welding without corrugated washers. 6. Reinforced removable thermal insulation (ASTI) according to claim 1, characterized in that the reinforcing frame lattice contains one reinforced rod profile, located in a linear dimension parallel to the axis of the cylindrical surface of the heat-insulated equipment and connected by a contact method to the second bar of the reinforcing frame lattice for a unified assembly of supporting frames of ASTI blocks for thermal insulation of the surface of any curvature of heat-insulated equipment. -