RU2788574C1 - Multilayer thermal screen-vacuum protection of high-temperature vacuum elevator, shaft and bell furnaces - Google Patents

Abstract

FIELD: thermal power engineering.

SUBSTANCE: invention relates to multilayer thermal insulation of high-temperature vacuum elevator, shaft and bell furnaces. The insulation consists of a heating block with heater strips, the body of which is attached to the furnace vacuum casing by means of brackets with adjusting screws, while the strip heaters are suspended on hangers mounted on metal studs through an insulator with a gap, a thermal block consisting of a casing and multilayer screens, made of overlapping plates, which hung on studs fixed in the body of the thermal block, while the distance between the plates is fixed by cups put on the studs and, additionally, by brackets in the form of channels between the studs, while holes are made in the body of the thermal block and screens through which current leads are introduced into the working volume and hearth supports, while the hearth and arch multilayer screens are made of layers consisting of round plates, fixed with pins, and part of the screens facing the working volume have a diameter smaller than the inner diameter thermal block, for entering the thermal block with providing a thermal lock, while the distance between the layers of the plates is fixed by cups put on the studs, and, additionally, by brackets in the form of channels installed between the studs.

EFFECT: technical result consists in increasing the operational stability of the thermal insulation of high-temperature vacuum elevator, shaft and bell furnaces.

1 cl, 8 dwg

Description

The invention relates to the field of thermal power engineering and is intended for use in high-temperature vacuum electric furnaces.

From document RU 103900 U1, publ. 04/27/2011 a heat-insulating screen made in the form of a multilayer system, including sequentially installed monolithic layers of carbon-containing material, while the layer located on the side of the high-temperature surface is made of heat-resistant composite carbon material, the layer in contact with it is made of low-density porous carbon material, and the outer layer is made of carbon fiber.

Also known from the prior art is a heat shield that contains an inner shell (1) in the form of a prefabricated frame, the shaped parts (2) of which consist of planks (4) interconnected by fastening rings 5 and studs 6 to form a cylindrical wall (7) with closed surface (3) of four layers of composite carbon material, and is characterized by heat resistance in an inert environment of 2500-3000°C. Each subsequent layer of the inner shell (1) is made tightly adjacent to the previous one with the possibility of creating a rigid structure. The first inner layer (8) is made of heat-resistant composite carbon-carbon material with a density of 1.8-1.9 g/cm3. The second layer (9) is made of thermally expanded graphite. The third layer (10) is made of heat-insulating non-woven highly porous carbon felt with a surface density of 80-120 g/m. The fourth layer (11) is made of structural graphitized carbon fabric with a surface density of 1000-1200 g/m (see EA 30577 B1, publ. 08/31/2018).

From the document SU 1515022 A1, publ. 10/15/1989 known lining, made of separate three-layer blocks with heat-insulating outer, working and intermediate layers, and the working and outer layers are rigidly connected to each other by means of an intermediate layer. The heat-insulating and working layers are made in the form of plates and are offset relative to each other, and the intermediate layer is equal in size to the size of the connected surfaces of the heat-insulating and working layers. high temperature composition.

The technical result consists in increasing the operational stability of the thermal insulation of high-temperature vacuum elevator, shaft and bell furnaces.

The technical result is achieved using multilayer thermal screen-vacuum protection of high-temperature vacuum elevator, shaft and bell furnaces consisting of:

- a heating unit with tape heaters, the body of which is attached to the vacuum casing of the furnace through brackets with adjusting screws, while the tape heaters hang on hangers mounted on metal studs through an insulator with a gap;

- a thermal block consisting of a body and a multilayer protection containing screens made in the form of plates that are overlapped and hung on studs to the body of the thermal block, the distance between the plates is fixed by cups put on the studs and, additionally, brackets in the form of channels between the studs , at the same time, current leads and hearth supports are introduced into the working volume through the body of the thermal block and screens through holes made in the body of the thermal block and screens,

and bottom and arched screen-vacuum protection, made of round-shaped plates fixed on studs, and part of the screens facing the working volume have a diameter smaller than the diameter of the internal thermal block to enter the thermal block, providing a thermal lock, the distance between the layers of the plates is fixed by cups , put on the studs and, additionally, brackets in the form of channels between the studs.

In FIG. 1 is a perspective view of the multilayer thermal screen-vacuum protection of high-temperature vacuum elevator, shaft and bell furnaces, in FIG. 2 - segment of the top view of the furnace in section; in fig. 3 - bracket for fixing the heating block; in fig. 4 - diagram of fastening of the thermal block, top view; figure 5 is a side view in section; figure 6 is a view of the hearth support in section; figure 7 - current lead with an insulator; in fig. 8 - bottom and arched screen-vacuum protection in section.

In the figures, positions 1-8 indicate:

1 - Flange of the vacuum body of the heating unit

2 - Vacuum body of the furnace

3 - current lead

4 - Fastening in the form of a hairpin of multilayer protection

5 - Tape heater

6 - Hearth table of the furnace

7 - Thermal block housing

8 - Sleeve

9 - Hairpin

10 - Staples in the form of channels

11 - Grooves

12 - Multi-layered protection

13 – Cups

14 - Suspension

15 - Hearth support

16 - Hole in the body of the thermal body

17 - Washer

18 - Insulator

19 - Plates of bottom and arched screen-vacuum protection

The heating block is made with band heaters 5. The material of the heaters depends on the operating temperature of the furnace. For temperatures up ^to 1100 ° C, they are made of high-temperature nichrome, for temperatures up ^to 1700 ° C - from lanthanated molybdenum or niobium, and for temperatures up ^to 2500 ° C - from tungsten. The heaters hang on hangers 14 mounted on metal studs 9 through an insulator 18, with a gap compensating the thermal expansion of the heaters.

The body of the heating block is mounted on brackets (figure 3) through the adjusting screws. The brackets are fixed to the vacuum body 2 of the furnace through the grooves 11 of the heating block with tape heaters 5, the body of which is installed through the grooves 11 on the adjusting screws in the brackets of the vacuum body, which during the assembly process allows you to combine the lower point of the axis of the thermal block with the axis of the chamber.

The thermal block consists of a housing 7 and multilayer screens made in the form of overlapping plates 12. When installing the thermal block, the adjusting screws allow the top point of the thermal block axis to be aligned with the axis of the furnace chamber. The thermal block is installed on the adjusting bolts through the grooves 11 (Fig. 4). Due to the grooves 11, the lower point of the axis of the thermal block is aligned with the axis of the chamber. Then, with the help of adjusting screws, the point of the axis of the thermal block is aligned with the axis of the chamber.

Thus, in the process of thermal deformations, the thermal body freely expands and narrows in diameter, and its axis relative to the installation body remains in place.

The top of the thermal block is not attached in any way, which allows it to expand freely in this direction.

The material of the screens and their number depend on the operating temperature of the oven. The screens are made in the form of separate plates, which are suspended only on two studs 4 installed in the body of the thermal unit. The holes in the plates are in the form of a groove, their axes are oriented perpendicular to the installation axis.

The distance between the layers of plates is fixed by cups 13 put on pins 9 and, additionally, by brackets in the form of channels 10 in the middle of the plates. This design allows the plates to freely expand and contract in all directions, but at the same time, retain their spatial position, which increases the service life of the screens several times.

Studs 9 are attached to the body of the thermal block section in bushings 8. The contact thermal resistance of such a connection reduces heat losses through studs 9 by several times compared to the welding connection option.

Current leads 3 and bottom supports 15 are introduced into the working volume through the body of the thermal block and screens. For this purpose, holes 16 are made in the body of the thermal block and screens much larger than the dimensions of the current leads and supports.

The resulting gap makes it easier to assemble and compensates for inaccuracies in the manufacture of parts, and also takes into account thermal deformations of the thermal block body and screens during operation. Washers 17 are installed on the support to eliminate heat losses through the gap formed on the support. Washers 17 are installed on the hearth supports 15 with a minimum gap and are located between the screens, so they do not prevent the movement of the thermal block body and screens relative to the supports 15 during thermal deformations, but completely cover the thermal radiation losses through the gap.

Current leads 3 are introduced into the working volume through insulators 18, excluding their electrical contact with the body of the thermal block and screens. Washers 17 are installed on current leads 3 similarly to bottom supports 15, only not on current lead 3, but on insulator 18.

Hearth and dome screen-vacuum protection, includes hearth and dome screens 19, which are made in the form of round plates. These plates are fixed on several studs 9, similarly to the screens of the thermal block. The screens are put on the central stud 9 without a gap, since it fixes their axis, and on the peripheral studs 9 through the grooves 11, made in the radial direction and allowing the hearth and arched screens to expand/contract freely during thermal deformations, while their axis remains on place.

Part of the hearth and dome screens 19, facing the working volume, have a diameter smaller than the inner diameter of the thermal block. The diameter of the remaining hearth and dome screens is larger. When assembling, plates with a smaller diameter fit into the inner diameter of the thermal block, thus providing a thermal lock that prevents heat loss. The distance between the layers of the hearth and dome screens is fixed by special cups 13, put on the studs 9 and, additionally, brackets 10 in the form of channels between the studs 9. This design allows the hearth and arch screens to expand and contract freely in all directions, but at the same time, retain their spatial position, which increases the service life of the screens several times. Studs 9 are attached to the section body in bushings 8.

The contact thermal resistance of such a connection reduces heat losses through the studs 9 by several times compared to the welding connection option.

Thus, the claimed solution provides an increase in the operational stability of the thermal insulation of high-temperature vacuum elevator, shaft and bell furnaces.

Claims (4)

Multilayer thermal insulation of high-temperature vacuum elevator, shaft and bell furnaces, consisting of: a heating unit with tape heaters, the body of which is attached to the vacuum casing of the furnace by means of brackets with adjusting screws, while the tape heaters are suspended on hangers mounted on metal studs through an insulator, with a gap, thermal block, consisting of a body and multilayer screens made of overlapped plates, which are suspended on studs fixed in the body of the thermal block, while the distance between the plates is fixed by cups put on the studs and, additionally, brackets in the form of channels between the studs, with At the same time, openings are made in the body of the thermal block and screens, through which current leads and bottom supports are introduced into the working volume, at the same time, the hearth and arched multilayer screens are made of layers consisting of round plates fixed with pins, and part of the screens facing the working volume have a diameter smaller than the inner diameter of the thermal block, for entering the thermal block with providing a thermal lock, while the distance between the layers of the plates is fixed by cups put on the studs, and, additionally, by brackets in the form of channels installed between the studs.

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