WO2024035273A1

WO2024035273A1 - Metallic thermal insulation

Info

Publication number: WO2024035273A1
Application number: PCT/RU2022/000355
Authority: WO
Inventors: Борис Владимирович КРАЙНОВ
Original assignee: Борис Владимирович КРАЙНОВ
Priority date: 2022-08-10
Filing date: 2022-12-05
Publication date: 2024-02-15

Abstract

The present metallic thermal insulation is comprised of thermally insulating blocks. Each block is filled with filtered air and contains a set of uniform coaxial self-fastening cylindrical membranes made of stainless steel sheet with a thickness of 0.07-0.1 mm. A cover and side walls of the blocks are made of stainless steel with a thickness of 0.2-0.4 mm, and a bottom has a thickness of 0.1-0.2 mm. The membranes form air gap chambers in the blocks, said chambers having a thickness of less than 15 mm. The surfaces of the membranes are arranged so that they curve through a uniform moveable positioning mesh made of wire and having moveable hollow cylindrical calibrating members fixed thereon. This relieves the membranes to the greatest possible extent of the effect of temperature and stresses. The side walls of the covers of adjacent blocks are connected to one another by lugs fastened to the corners of the walls of the covers of the blocks. When four adjacent sectors of such lugs are joined together, a single solid of revolution is formed which seals itself into a removable clamping head. The side walls of the bottoms of four adjacent blocks are connected to one another with the aid of cylindrical guide pins which are fastened to the bottoms of the blocks and fit snugly into four recesses in a metallic centering socket. The thickness of the thermally insulating blocks is reduced from 160 mm to 96 mm and at the same time radiation shielding from gamma radiation is increased.

Description

Metal thermal insulation (MIT)

The invention relates to thermal insulation technology, and more specifically to the designs of thermal insulation of pipelines and cylindrical vessels of nuclear thermal power plants (NPP).

Removable thermal insulation is known, containing thermal insulation blocks of block removable thermal insulation (hereinafter referred to as BTI) placed on the outer surface of heat-insulated equipment close to each other, joined together by longitudinal side walls and including boxes made of stainless steel and filled with thermal insulation material (see Russian patent RU2716771C2 - 2020, application RU No. 2017111880 dated 04/07/2017). This patent (with explanations of the BSTI material) is taken as a prototype.

The disadvantage is that the patent uses a heat-insulating material made of fiberglass in its design. When the primary circuit decompresses, the possibility of glass fiber entering the reactor core cannot be ruled out.

The relatively thick-walled cover of the heat-insulating block (hereinafter referred to as TB) BSTI, 1 mm thick, is made to avoid decompression of the TB and burns when fastening by welding tight lever locks that tighten the TB together. Lever turnbuckles are attached to the BSTI TB covers using studs that are welded to the TB covers by melting the pins at a current of 10,000 amperes. The MTI locks proposed in the application are located on the corner sections of the TB covers and are attached to local pads by conventional welding without the use of reflow. All TB BSTI covers contribute 29.5t to the total weight of BSTI insulation, equal to 66.96t. All MTI TB covers contribute 10.2 tons to the total MTI insulation weight of 34.79 tons. The reduction in the overall weight of the MTI was achieved due to the smaller thickness and height of the side walls, the reduced thickness of the TB covers, the locks securing the TB, and the exclusion of 25 tons of fiberglass with clips from the BSTI composition. By recalculating the load on the walls of the TB MTI, in comparison with the load on the walls of the TB BSTI, the thickness of the walls of the TB MTI is equal to 0.247 mm. In strength and weight calculations, the thickness of the MTI walls, conservatively as a reserve, was taken to be 0.3 mm. The maximum static load on the walls of the BST, with a wall thickness of 0.5 mm, is 0.0134 kg/cm ² . The maximum static load on the walls of the MIT, with a wall thickness of 0.3 mm, is 0.00977 kg/cm ² .

The objectives of the proposed invention are: to create thermal insulation that is more advanced than block removable thermal insulation (BRI) installed at the Tianwan NPP (PRC), at the Kudankulam NPP and at most nuclear power plants in the Russian Federation, to exclude fiberglass from the insulation composition and replace it with atmospheric air, reducing the thickness of the walls of the TB to 0.3 mm, ensuring the optimal height of the heat-insulating block while maintaining its thermophysical characteristics, reliable fastening of membranes, fastening adjacent module bottoms to each other with a constant tight connection during operation, creating locking connections of block covers with self-sealing during seismic, vibration, temperature and other fluctuations, reducing the weight of thermal insulation by a total of 32.17 tons (48%). The metal set inside the housing devices (VKU), similar to the device of a multilayer metal thermos, consists of self-attaching unified membranes made of elastic stainless steel sheet with a thickness of 0.07-0.1 mm.

The main solution of the invention is to reduce the thickness of the side and end walls of the heat-insulating block BSTI and, as a consequence, reduce heat transfer through them by conduction. As the thickness of the block walls decreases, the length of heat transfer by thermal conductivity decreases, and, as a result, the thickness and weight of the thermal insulation as a whole decreases.

Metal thermal insulation (MTI), containing heat-insulating blocks placed on the outer surface of the heat-insulated equipment close to each other, including boxes joined together by longitudinal side walls, made of stainless steel and filled with filtered atmospheric air.

The cover and side walls of the blocks are made of stainless steel sheets with a thickness of 0.2-0.4 mm, the bottom - with a thickness of 0.1-0.2 mm, sets of membranes are made of self-attaching sheets of stainless metal with a thickness of 0.07-0.1 mm, located between the walls of the block and adjusted to size in place during assembly.

The membrane row of TBs is made using unified elastic membranes with the same cylindrical curvature equal to the curvature of the TB bottom, the surfaces of the membranes are made convexly directed through a unified movable coordinate wire grid, with fixed movable hollow cylindrical gauges, towards the TB cover. The seal between the air gap chamber and the side wall of the block body is made of a longitudinal wavy strip, which is a continuation of the membrane on the longitudinal edge, bent at an angle of more than 90 degrees. The seals between the air gap chambers and the end walls of the TB are made using membranes and the butt ends of strips of cylindrical plinths, adjusted in place during the assembly of the TB and secured by welding corners with the side walls of the TB.

Thin-walled membranes form chambers of air layers of the block with a thickness of less than 15 mm. The dimensions of the membranes increase from the bottom to the lid in proportion to the lengths of the arcs of each subsequent row by the amount:

. _tZitApY

^db = -360'- ^g ® ^:

AL - increase in the arc length of the membrane surface of the subsequent row;

A p - the gap from the surface of the previous row of membrane to the surface of the membrane of the next row, is in the range of 5 - <15mm;

Y is the angle between the contact elements of flexible membranes with the walls of the block.

A thermostatic gap, <15mm thick, as the primary insulating air layer of the ring section, is installed between the bottom and the heat-insulated body using sockets.

The side walls of the covers of adjacent blocks are connected to each other using tip-hooks attached to the corners of the walls of the block covers and made in the form of a separate identical sector of the fourth part of the body of rotation: a ball or an ellipsoid in such a way that when four adjacent sectors are assembled, a single body of revolution is formed, self-sealing in a removable funnel-grabber; in the working position of the funnel-grabber, elastic petals provide tight compression of the hook tips, and when the hook tips pass the neck of the grab funnel under the action of an applied force, the ability to elastically unclench and then return to its original position. A detachable elastic ring is additionally mounted on the grab funnel, providing additional compression.

The side walls of the bottoms of four adjacent blocks are connected to each other using guide cylindrical pins attached to the bottom of the block and fit tightly into the four sockets of the centering metal socket.

Access to possible sensors located on the equipment under thermal insulation is achieved using cylindrical penetrations. The seal between the air gap chamber and the side wall of the block body can be made with a longitudinal flat strip, which is a continuation of the membrane on the longitudinal edge, bent at an angle of more than 90 degrees.

Hollow gauges can be made into rectangular or triangular trapezoids with a height of < 15mm.

Thus, the patented MIT has the following differences from the prototype:

1. The reduced thickness and height of the walls and cover of the TB, as well as reduced heat transfer by thermal conductivity, optimize the thickness of the thermal insulation blocks from 160 mm to 96 mm.

2. Fiberglass was replaced with atmospheric air. The penetration of glass fiber into the coolant circuit and the reactor core is excluded.

3. Calibration between unified membranes that perform thermal insulation functions is carried out uniformly and maximally relieves the membranes from the effects of temperature and force factors.

4. Thermal insulation of MTI when replacing thermal insulation materials with atmospheric air is lighter by 32.17 tons (48%) compared to the currently used block removable thermal insulation (BRI) at modern nuclear power plants in the Russian Federation, China and India. MTI blocks, consisting of thin-walled and axially symmetrical coaxial membranes, have low metal consumption and the most favorable physical properties for tensile and compression, evenly distributed bending moment forces along the perimeter and length of the heat-insulated surface.

5. Due to the tight connection of adjacent covers and bottoms of blocks using sealing locks and sockets, self-compensation of locking connections of block covers during sharp seismic, vibration, temperature and other fluctuations, the opening of thermal gaps between the side faces of heat-insulating modules is excluded.

6. Placing flexible locks in the corners at the intersection of MTI surfaces completely eliminates numerous local marking, fitting and welding work when installing 6000 locks on the thermal insulation of the object.

7. Increase in the composition of thermal insulation of radiation protection material (MIT metal membranes) from gamma radiation on equipment and pipelines of the reactor compartment without increasing the total weight of the insulation.

8. Increasing the efficiency and reliability of safety systems in case of accidents associated with decompression of the primary circuit.

Table of comparative characteristics of BSTI of Kudankulam NPP and MIT

There are three types of heat transfer: conduction, convection and radiation.

In the invention of thermal insulation, the leader in the thickness dimension of the MTI is the thermal conductivity of the side and end walls of the block, which determines the height of these walls and, as a consequence, the thickness of the thermal insulation as a whole, selected in accordance with the requirements of regulatory documentation. Thermal bridges are significant - the joint junction of four adjacent TBs, their intersections, which increase the local total thickness of the side walls.

Fourier's law of thermal conductivity in integral form:

P is the total power of thermal transfer; x - thermal conductivity coefficient;

S - cross-sectional area;

AT - temperature difference;

1 - length of the heat-conducting body.

Source: Dictionaries and encyclopedias on Academician.

From the linear Fourier law of heat transfer by thermal conductivity it follows that with identical parameters of the total heat transfer power, thermal conductivity coefficient, temperature difference between BSTI and MTI, the heights of the walls of BSTI blocks and MTI blocks will be proportional to the cross-sectional areas of the walls, that is, the wall thicknesses. The maximum thickness of BSTI blocks is 160mm at wall thickness 0.5mm. With a wall thickness of the MTI block equal to 0.3 mm, the maximum thickness of the MTI block is 96 mm, which is confirmed experimentally.

It has been experimentally proven that thinner layers, in which the air can be considered almost motionless, have a lower thermal conductivity coefficient than thicker layers with convection currents arising in them. The thermal conductivity coefficient of a layer of air up to 15 mm thick is 0.035. An air gap up to 15 mm thick can be considered an insulator with a fixed layer of air, Source: Technical Encyclopedia. Volume 4 - 1928

Installing one screen between two parallel walls reduces heat transfer by radiation by approximately two times. The design of seven thin air layers with fixed layers of air, edged with polished steel membranes, can reduce heat transfer by radiation by more than 100 times.

A cascade of metal membranes shields the outer surface of the MTI from radiant heat transfer, and practically motionless air is a good insulator from thermal conductivity from the membranes of hotter air layers.

Figure 1 shows an MIT TB with a closed case;

Figure 2 shows a fragment of the cross section of TB MIT;

Figure 3 shows a wire frame lattice;

Figure 4 shows a top and end view of the wire frame lattice;

Figure 5 shows a hollow cylindrical gauge;

Figure 6 shows the mechanical seal of the membrane using a plinth;

Figure 7 shows a membrane with sealing strips;

Figure 8 shows a hook tip;

Figure 9 shows a capture funnel;

Figure 10 shows the fastening of the covers and bottoms of the MTI blocks;

Figure 11 shows a schematic fastening of adjacent MTI blocks with locks;

Figure 12 shows the fastening of the bottoms of the MTI blocks.

Figure 1 shows an MTI TB, consisting of a cover, position 1, two side walls, position 2, located at an angle Q to each other, two end walls, position 3, made in the form of flat annular sectors, and a cylindrical bottom, position 4. resting through pins pos. 15 and sockets pos. 16 on the heat-insulated surface pos. 5. The thermostatic gap pos. 9, thickness < 15 mm, as the primary insulating air layer of the annular section, is installed between the bottom pos. 4 and the heat-insulated body pos. 5. At the corners of the end and side walls of the cover there are hook tips, position 18, for connecting the TBs to each other using a funnel-grabber, position 19. The thermostatic gap pos. 9, <15 mm thick, as the primary insulating air layer of the ring section, is installed between the bottom pos. 4 and the heat-insulated body pos. 5 in thickness using sockets pos. 16.

Figure 2 shows a cross-sectional fragment of a part of the MTI TB. Membranes pos. 6 are installed without gap with the walls of the block. The package of six membrane assemblies is finally secured by a welded connection of longitudinal channels pos. 8 and stiffeners pos. 26, cover pos. 1, bottom pos. 4 with side and longitudinal walls. Membranes pos. 6 form chamber air layers pos. 17 with a layer thickness < 15 mm, in which the air is stationary and there are no convective currents. The membranes are calibrated with each other using hollow cylindrical gauges pos. 25 with a height of less than 15 mm, providing a gap D between the membranes. The thickness of TB MTI ranges from 72mm to 96mm depending on the temperature of the heat-insulated body. The curvature of the cylindrical surface of the membranes decreases with increasing surface radius. Inside, the housing device of the TB membrane series is made using unified elastic membranes with the same greatest cylindrical curvature equal to the curvature of the TB bottom, that is, the contacting surfaces of the membranes with hollow cylindrical gauges are made, providing in normal mode a number of contacting spring-loaded surfaces, starting with the first membrane closest to the bottom and having the greatest curvature of the row, reinforcing the cylindrical surface of the subsequent membrane, which has a unified bottom curvature before installation and is restored naturally during installation using hollow cylindrical gauges to a curvature corresponding to the curvature of the radius of the installed membrane. When restoring the surface of the membrane from greater to lesser curvature, due to the elasticity of steel, the membrane works as a kind of shock-absorbing spring and a series of elastic membranes with hollow calibers are obtained, directed by a reinforcing force to the cover of the TB and unloading the bottom of the TB.

Figure 3 shows an isometric view of the wire frame lattice. The grid cell pitch, depending on the size of the corresponding membrane, is in the range of 150-250mm. Solid steel stainless wire pos. 23 with a diameter of 0.5-1.5 mm, passing through holes with a diameter of 0.6-1.6 mm, made in hollow cylindrical gauges pos. 25, connects the movable gauges, forming a coordinate movable lattice. Thus, a unified movable wire grid with movable gauges makes it possible to calibrate a sheet surface of any volumetric curvature with any geometric outline of the sheet perimeter using a wire frame. The unification of the membrane is based on the fact that, with membrane sizes of 1000x1000 mm (the average dimensions of the outer surface of the fuel tank at Kudankulam NPP and Tianwan NPP) and the height of the membrane row in the tank up to 100 mm for a given radius of the heat-insulated body, cantilever deviations relative to the longitudinal axis of symmetry of the tank the very first and very last membranes of the row differ by 3.5% (which corresponds to the angle of deviation of the half-arc of the membrane by 2°). Taking as a basis a unified membrane with the greatest curvature, that is, the membrane closest in the TB series to the heat-insulated body, during installation using equal-height hollow gauges, the curvature of each mounted membrane is restored to the corresponding deflection angle of up to 2°, while maintaining the gap D p along throughout the air gap chamber within acceptable limits.

Figure 4 shows a top and end view of a movable wire grill. Hollow cylindrical gauges pos. 25 without fixation slide coordinately along the wire frame pos. 23.

Figure 5 shows a hollow cylindrical caliber rose 25. To coordinately fix the gauge using a sealer, simple deformation of the wire, pos. 27, is used at the point of contact with the gauge. For example, a wire with a diameter of 1mm is deformed to a size of 0.4x1.96mm. At the end sections, the wire is cut and a bend is made, position 28, along the surface of the gauge. The ends of the gauge are made with a curvature equal to the curvature of the corresponding membrane. The hollow cylindrical gauge, depending on the geometric outline of the membrane perimeter, can be made into a rectangular or triangular trapezoid.

Figure 6 shows the sealing of the wall, pos. Figure 7 shows the membrane pos. 6 with sealing strips pos. 7 and pos. 11. The width of the strips is in the range of 5-10mm. The sealing strip can be made in a wavy version, pos. 7, and in a flat version, pos. 11. The bend angle q of the sealing strip must be greater than 90°.

Figure 8 shows the hook tip pos. 18 with a radius of curvature of 1*1. The hook tips are turned on a lathe and cut into 4 equal parts. Installation is carried out and argon arc welding is used to connect pos. 10 to the cover pos. 1.

Figure 9 shows a removable funnel-grabber pos. 19, which is the counterpart of the hook tips pos. 18. Its elastic part is made of longitudinal petals pos. 20 in the form of a thin-walled body of rotation, with a neck - the narrowest point of compression of the longitudinal petals. To increase elasticity when connecting the covers of large blocks, an open elastic ring, pos. 12, is additionally mounted on the neck of the unified gripper funnel, which is secured to the gripper funnel with clamps pos. 13 using resistance welding. The elastic part of the grab funnel is fixed to the cylindrical shell pos. 21 using contact welding. The elastic funnel-grabber pos. 19 is designed in such a way that in its working position the elastic petals of pos. 20 are designed to compress the tip-hooks pos. 18, and when the tip-hooks pass the neck of the funnel-grab - the narrowest point of compression of the longitudinal petals, under the action of the applied force, the petals elastically unclench and then return to their original position.

Figure 10 shows the fastening of the covers and bottoms of the MTI blocks. Shown is the standard assembly of hook tips, pos. 18, with a radius of curvature n of adjacent heat-insulating blocks with a removable elastic funnel-gripper, pos. 19.

Funnels-grabs are made with bottoms pos. 22. The bottoms of four adjacent blocks are connected to each other using cylindrical guide pins pos. 15, which fit tightly into the four sockets of the centering socket pos. 16.

Figure 11 shows a schematic fastening of MTI blocks with locks in the angular junctions of the boundaries of the blocks, position 14. Angular fastening of blocks allows avoiding adjustment and welding of ~ 6000 locks with TB covers when installing locks in the nuclear power plant area.

Fig. 12 shows the connection with the bottoms of the TB, pos. 4, of the guide cylindrical pins, pos. 15, with the centering socket, pos. 16, resting on the heat-insulated body, pos. 5. Tight connection of the TB bottoms using sockets is very important because any cylindrical surface of the heat exchange shell has a natural permissible ellipse. When the TB is assembled into a ring around a heat-insulated body, uncontrolled ellipse also occurs on the inner surface of the TB. With an unfavorable, especially perpendicular coincidence, of the above-mentioned surface ellipses, gaps and unacceptable decompaction of the TB bottoms arise, which lead to a deterioration in the thermal insulation properties of the MTI TB.

Estimated calculation of block cover thickness

When using reinforcement of the cover with ribs 14 mm high and 0.3 mm thick, the following data are obtained:

The thickness of the stainless thin-walled steel shell of BSTI is equal to Sf = kiD P/[6]J The thickness of the stainless thin-walled steel shell of MIT is equal to S ₂ = kg d P/[6] ;

51 kiD VP/[6] kiD

5 ₂ k ₂ dVP/[6] k ₂ d , canceling the radicals, we find that Si kg d 1.0 x 0.56 x 200

S ₂ = - = - = 0.26 mm, where: kiD 0.43 x 1000 d - step of the cell for reinforcing the ribs of the MTI cover, equal to 200 mm;

D - size of the BSTI block cover, equal to 1000 mm;

Si and S ₂ - thicknesses of stainless thin-walled steel covers BSTI and MIT; ki and k ₂ are coefficients that take into account the method of securing the edges of facing steel shells. The formulas for calculating the thickness of the covers of TB MTI and TB BSTI are taken as a conservative reserve, as for a flat bottom operating under external pressure.

Source: “Standards for strength calculations of equipment and pipelines of nuclear power plants.” PNAE G-7-002-86. Moscow, 1989

Taking into account the thickness of the BSTI cover equal to Si = 1.0mm, ki = 0.56, D = 1000MM, k ₂ =0.43, 1 = 200mm, we obtain a preliminary equal-strength thickness of the stainless thin-walled cover equal to S ₂ =0.26MM. Taking the thickness of the stainless thin-walled cover of the MTI TB equal to S ₂ = 0.3 mm, we obtain a safety margin of the MTI TB cover for external uniform loads that is 1.15 times greater than that of the BSTI TB cover. According to calculations of bending moments, the safety factor is even higher since the linear dimensions in the formulas are included in quadratic ratios.

Approximate weight calculation for MIT

The number of membranes and chambers in the MTI block depends on the total power, the heat flow from the surface of the thermally insulated body and the difference in the temperature difference of the diesel engine between the surfaces of the thermally insulated body and the outer surface of the MTI. For an approximate estimate of the weight of the MTI, a variant of the MTI block with an integral heat flux density from the module surface of no more than 290 W/m ² , with six membranes 0.1 mm thick, seven chambers of air layers, with a distance between the membranes p = 14 mm, with wall thickness and block covers 0.3mm, bottom thickness 0.1mm. The diameter of the wire frame is 1.0mm, the gauge thickness is 0.2mm and the gauge diameter is 10mm according to GOST 9941-81. The total weight of the MTI per 3758 ^m2 (the outer area of the entire BST of the Kudankulam NPP, India) is 34.79 tons.

The weight of the MTI is equal to: 10.2t (sum of weights of all covers with reinforcements of 10 ribs S=0.3MM, 200mm pitch)+2.83t (sum of weights of all walls)+16.2t (sum of weights of all membranes)+1.8t ( sum of weights of wire frames with hollow cylindrical gauges) + 2.4 t (bottom weight) + 0.86 t (sum of weights of all locks and sockets) + 0.5 t (sum of weights of all skirting boards, fastening angles and sealing strips) - 34.79 t Average height of MTI = 80.02 mm.

The weight of the BST is equal to: 30.0t (the sum of the weights of all covers) + 7.88t (the sum of the weights of all walls) + 25.0t (the weight of all the glass fabric of the BST) + 1.68t (the sum of the weights of all locks) +2, 4t (the weight of the bottom ) = 66.96t. Average height of BSTI = 133.6 mm.

BSTI parameters for Kudankulam NPP for calculating the average height

The reduction in the weight of the entire thermal insulation of MTI per one NPP Unit, according to an approximate estimate, compared with the weight of the existing BTI of the Kudankulam NPP - India (66.96 tons), is 32.17 tons (48%).

Specifying terms

1. Cover

2. Side wall of the block

3. End wall of the block

4. Bottom

5. Heat insulated body

6. Membrane

7. Wavy stripe

8. Longitudinal channel

9. Thermostatic gap

10. Argon arc welding

11. Sealing strip

12. Elastic ring

13. Clamp

14. Block border

15. Guide pin

16. Centering socket

17. Air gap chamber

18. Tip-hook

19. Capture funnel

20. Petal

21. Shell

22. Donyshko

23. Wire frame

24. Cylindrical plinth

25. Hollow cylindrical gauge

26. Cover stiffener

27. Deformable part of the wire

28. Bent part of deformable wire

29. Mounting corner

Claims

Claim

1. Metal thermal insulation (MTI) contains heat-insulating blocks placed on the outer surface of the heat-insulated equipment close to each other, including boxes joined together by longitudinal side walls, made of stainless steel and filled with filtered atmospheric air; the cover and side walls of the blocks are made of stainless steel sheets with a thickness of 0.2-0.4 mm, the bottom - with a thickness of 0.1-0.2 mm, sets of membranes are made of self-attaching sheets of stainless metal with a thickness of 0.07-0.1 mm, located between the walls of the block and adjusted to size in place during assembly; the TB membrane series is made using unified elastic membranes with the same cylindrical curvature equal to the curvature of the TB bottom, the surfaces of the membranes are made convexly directed through a unified movable coordinate wire grid, with fixed movable hollow cylindrical gauges, towards the TB cover; the seal between the air gap chamber and the side wall of the block body is made of a longitudinal wavy strip, which is a continuation of the membrane on the longitudinal edge, bent at an angle of more than 90 degrees; seals between the chambers of the air gaps and the end walls of the TB are made using membranes and butt ends of strips of cylindrical plinths, adjusted in place during the assembly of the TB and secured by welding corners with the side walls of the TB; thin-walled membranes form the chambers of the air gaps of the block with a thickness of less than 15 mm; the dimensions of the membranes increase from the bottom to the lid in proportion to the lengths of the arcs of each subsequent row by the amount:

AL - increase in the arc length of the membrane surface of the subsequent row;

D r - the gap from the surface of the previous row of membrane to the surface of the membrane of the next row, is in the range of 5 - <15mm;

Y is the angle between the contact elements of flexible membranes with the walls of the block; a thermostatic gap, <15 mm thick, as the primary insulating air layer of the ring section, is installed between the bottom and the heat-insulated body using sockets; the side walls of the covers of adjacent blocks are connected to each other using hook tips fixed to the corners of the walls of the block covers and made in the form of a separate identical sector of the fourth part of the body of rotation: a ball or ellipsoid in such a way that when the four adjacent sectors are assembled, a single body of rotation is formed, self-sealing in a removable funnel-grabber; in the working position of the funnel-grabber, the elastic petals provide tight compression of the hook tips, and when the hook tips pass the neck of the grab funnel under the action of an applied force, the ability to elastically unclench and then return to its original position; a detachable elastic ring is additionally mounted on the grab funnel, providing additional compression; the side walls of the bottoms of four adjacent blocks are connected to each other using guide cylindrical pins attached to the bottom of the block and fit tightly into the four sockets of the centering metal socket; access to possible sensors located on the equipment under thermal insulation is carried out using cylindrical penetrations.

2. Metal thermal insulation (MTI) according to claim 1, characterized in that the seal between the air gap chamber and the side wall of the block body made by a longitudinal flat strip, which is a continuation of the membrane on the longitudinal edge, bent at an angle of more than 90 degrees.

3. Metal thermal insulation (MTI) according to claim 1, characterized in that the hollow calibers are made of rectangular or triangular trapezoids with a height of <15mm.