RU2632049C2 - Chamber furnace with roll-out hearth - Google Patents

Abstract

FIELD: metallurgy.

SUBSTANCE: chamber furnace comprises an end wall which is the roll-out hearth made with side framing and a knife with bevelled edge horizontally installed, and a thermal gate installed under side framing of the hearth. The thermal gate is made in form of bearing surfaces, between which there is a base with sealing material placed layer-by-layer therein, and configured to enter between the layers of said knife. The roll-out hearth comprises a load-bearing transverse beam which is fastened to the side frame of the hearth and to which said knife is welded. The end wall of the furnace comprises a discharge arch with ceramic fibre blocks lined thereunder. The sealing material is fixed on the bearing surfaces by a stainless circle to prevent it from falling out during return movement of the hearth.

EFFECT: improved reliability of the furnace hearth end sealing.

4 cl, 2 dwg

Description

The invention relates to the field of construction of chamber furnaces with a rolling hearth, performing reciprocating motion in a horizontal plane relative to the furnace frame and used in the heat treatment of metals.

Known furnace with a rolling hearth, containing a thermal shutter mounted on the frame of the furnace box, a knife attached to the bottom of the furnace, and a seal, fixed along the entire length of the knife, made in the form of a free-hanging asbestos fabric, reaching the bottom of the box [1].

The disadvantage is the inability to use a thermal shutter to seal the end of the furnace hearth, since the claimed shutter can only work with the longitudinal movement of the seal relative to the axis of the box. With transverse movement of the seal, i.e. when located at the end of the hearth, the reliability of the seal is reduced. This is due to the fact that during the transverse movement of the seal, it breaks, which leads to the destruction of the seal.

A known hearth furnace in the form of a seal of the perimeter of the furnace, containing a stationary box with a heat-insulating hollow elastic element and a knife located in it, the seal is equipped with a horizontal partition installed inside the heat-insulating hollow elastic element, dividing the cavity of the element into two parts. In this case, the seal has a cylinder installed in the box, associated with the depressurization cavity, and the partition is made with a rod that can be moved in the cylinder [2].

However, the reliability of the seal is reduced. This is due to the presence of a significant amount of a soft hose insulated with fibrous materials, which gradually collapse upon constant contact with a steel knife, which leads to untimely supply of compressed air to the soft hose and, as a result, to the uninterrupted operation of the vacuum pump. Violation of the vacuum pump leads to failure of the seal and the breakthrough of combustion products in the sub-subspace.

The closest solution to the proposed technical essence is a furnace with a roll-out hearth, containing an end wall and a roll-out hearth, made with a side frame and a horizontally mounted knife with a beveled edge [3].

The disadvantage of this device is that the seal is a set of molded parts: cast movable knife with eyes, rollers, complex molding, some of which rotate in an atmosphere of high temperature and dust, which will inevitably lead to malfunctioning of the seal, resulting in reliability of the seal declining. Also, the issue of overlapping the gap between the bottom of the hearth and the end wall of the furnace is not resolved due to the inability to ensure a tight fit of the hearth to the lining of the end wall without destroying the lining and plate. Through leaks, the combustion products of the fuel will damage the protective plate due to its thermochemical corrosion and, further, the cast movable knife and its hinge connection with the cast supporting structure. As a result of the destruction of these elements, the combustion products inevitably penetrate into the under-water space and disable the metal structures and the hearth chassis, as well as the rail track.

The present invention solves the problem of increasing the reliability of sealing the end of the hearth by protecting against breakthrough of combustion products in the under-subspace of the furnace.

The problem is achieved in that in a chamber furnace with a roll-out hearth containing an end wall and a roll-out hearth, made with a side frame and a horizontally mounted knife with a beveled edge, according to the invention, the furnace is equipped with a thermal shutter installed under the side frame of the hearth and made in the form of load-bearing surfaces, between which a base is installed with a sealing material layer-by-layer laid in it with the possibility of entry between its layers of said knife by means of a beveled edge, while The underside contains a supporting transverse beam fastened to the side frame of the hearth and to which the aforementioned knife is welded, and the end wall of the furnace contains an unloading arch with ceramic-fiber blocks lined under it, and the upper part of the said blocks is displaced relative to the working surface of the hearth and hangs over it when placing the hearth in the working position inside the furnace, and the lower part comes into close contact with the side frame of the hearth, while the sealing material is fixed on the bearing surfaces with stainless steel ogom to prevent its loss during the return movement of the hearth.

In this case, the base is made of channel.

In this case, the bearing surfaces are made of steel sheet.

At the same time, ceramic fiber is used as the sealing material.

The content of the furnace end wall under the unloading arch with ceramic-fiber blocks lined under it, the upper part of which is offset from the working surface of the hearth and hangs over the working surface of the hearth when the hearth is placed in the working position inside the furnace, and the lower part comes into close contact with the side frame of the hearth allows you to form self-clamping labyrinth seal between the hearth and end wall without destroying the lining due to the elastic properties of the ceramic fiber and thereby prevent breakthrough combustion products, which increases the reliability of sealing the bottom of the furnace hearth.

The implementation of the thermal shutter in the form of bearing surfaces, between which a base is installed with sealing material layered in it with the possibility of entering between its knife layers due to a beveled edge, contributes to additional protection of the under-water space, which eliminates the breakthrough of combustion products into the sub-water space through the gap between the end face and the end wall of the furnace.

Due to the beveled edge, the knife enters between the layers of sealing material and forms a “response” surface in it, which, due to the specific properties of ceramic fiber, retains its shape and provides a stable density of compaction.

Welding the knife to the supporting transverse beam of the hearth fastened with the side frame creates its reliable fixation against the bearing surfaces of the thermal shutter and excludes the presence of rotating parts in the thermal shutter, provides a stably reliable seal, resistant to high temperatures and mechanical stresses.

The installation of a thermal shutter under the side frame of the hearth eliminates the penetration of combustion products into the under-water space, increases the reliability of sealing the end of the hearth of the furnace.

The use of ceramic shutter thermal seal as a sealing material and its layer-by-layer laying contributes to the stable operation of the thermal shutter at various temperatures, the autoformation of the “mating” surface for the knife and its preservation for a long time, which excludes the penetration of combustion products into the subpod space.

The fixation of the sealing material laid between the base and the bearing surfaces of the hearth to the bearing surfaces with a stainless circle prevents the material from falling out during the return movement of the hearth, as a result of which the reliability of the sealing of the end face of the furnace increases.

The implementation of the basis of the channel provides reliable fixation of the thermal shutter to the frame of the furnace and its stable location relative to the knife.

The implementation of the bearing surfaces of the thermal shutter from a steel sheet provides support for ceramic fiber blocks and uniformity of packing of the sealing material.

The invention is illustrated by drawings, where:

in FIG. 1 - presents a chamber furnace with a rolling hearth, a cross section;

in FIG. 2 is a view A in FIG. 1, a thermal shutter installed under the side frame of the hearth is shown.

The following designations are accepted in accordance with the assembly sequence:

1 - end wall

2 - unloading arch

3 - blocks of ceramic fiber cloth

4 - the working surface of the hearth

5 - side frame of the hearth

6 - bearing surfaces

7 - base

8 - sealing material made of ceramic fiber

9 - shutter knife

10 - hearth crossbeam

11 - stainless circle.

The bogie-hearth chamber furnace comprises an end wall 1 of the furnace with an unloading arch 2 placed therein with ceramic-fiber blocks lined under it 3. Ceramic-fiber blocks 3 are mounted vertically on top of each other. The upper part of the ceramic fiber blocks 3 is offset relative to the working surface of the roll-out hearth 4 and hangs over it when the hearth 4 is placed in the working position inside the furnace. The lower part of the blocks 3 is in close contact with the side frame 5 of the roll-out hearth. The furnace is equipped with a thermal shutter installed under the side frame 5 of the hearth, made in the form of bearing surfaces 6. Between the bearing surfaces 6 of the thermal shutter a base 7 is installed with layer-by-layer sealing material 8 made of ceramic fiber. The knife 9 is welded horizontally to the supporting transverse beam 10 of the roll-out hearth, which is fastened to the side frame 5 of the hearth. Knife 9 has a beveled working edge in the form of a single or double-sided wedge, made of steel sheet, for example, sheet 20 St3, St5, St20, St09G2S. Due to the beveled edge, it is possible for the knife 9 to enter between the layers of the sealing material 8 and the formation of a “mating” surface in it. The "response" surface, due to the specific properties of ceramic fiber, retains its shape. The base 7 is made of steel, for example, channel No. 20U St3kp, St3ps, St3sp GOST 8240-97. Bearing surfaces 6 are made of steel sheet, for example, sheet 20 St3, St5, St20, St09G2S. The bearing surfaces 6 of the thermal shutter serve as a support for the ceramic fiber blocks 3, which are lined with the end wall 1 under the unloading arch 2. The sealing material 8 is fixed on the bearing surfaces 6 of the thermal shutter with a stainless circle 11 to prevent it from falling out during the return movement of the hearth. The sealing material 8 and blocks 3 are a ceramic fiber cloth, for example, of the type LYTX - 1427Z. The gap remaining between the ceramic fiber blocks 3 and the working surface 4 of the hearth is a labyrinth seal, preventing the breakthrough of the combustion products of fuel into the under-subspace of the furnace.

Chamber furnace roll-out hearth works as follows.

When the roll-out hearth is installed in the working position, the lower part of the ceramic fiber blocks 3 comes into contact with the working surface 4 of the hearth and the side frame 5, is deformed, takes the form of the surface of the frame and retains this deformation, and thus, the furnace’s working space is automatically densified. The knife 9, due to the beveled edge, enters between the layers of the sealing material 8 and forms a “mating” surface in it, repeating the configuration of the knife 9, which, due to the specific properties of ceramic fiber, retains its shape. With further reciprocating movements of the roll-out hearth in accordance with the production cycle, the knife 9 is located inside the "return" surface and provides a stably reliable seal against breakthrough of the combustion products into the sub-subspace, resistant to high temperatures and mechanical stresses.

Thus, the proposed chamber furnace with a roll-out hearth provides reliable protection against breakthrough of combustion products into the sub-sub-space, is easy to manufacture, contains a minimum of components and is devoid of rotating parts. The economic effect of the application of the invention is achieved by reducing the cost of repairing the end wall under the unloading arch and increasing the operational resource of the rolling hearth.

Information sources

1. USSR author's certificate No. 879223, IPC F27B 3/10, publ. 11/07/1981.

2. USSR Author's Certificate No. 920344, IPC F27D 1/18, F27B 3/10, publ. 04/15/1982.

3. USSR author's certificate No. 254031, IPC F27B 3/06, F27B 9/30, publ. 03.24.1970 - a prototype.

Claims (4)

1. Chamber furnace with a roll-out hearth, comprising an end wall and a roll-out hearth, made with an onboard framing and a horizontally mounted knife with a beveled edge, characterized in that it is equipped with a thermal shutter installed under the onboard framing of the hearth and made in the form of bearing surfaces between which a base is installed with the sealing material laid in layer-by-layer with the possibility of entry of said knife between its layers by means of a beveled edge, while the roll-out one contains a supporting transverse beam which is fastened to the side frame of the hearth and to which the knife is welded, and the end wall of the furnace contains an unloading arch with ceramic-fiber blocks lined under it, the upper part of the said blocks being offset from the working surface of the hearth and hanging over it when the hearth is placed in the working position inside the furnace and the lower part - comes into close contact with the side frame of the hearth, while the sealing material is fixed on the bearing surfaces with a stainless circle to prevent it from falling out tions during the return movement of the hearth. 2. Chamber furnace with a roll-out hearth according to claim 1, characterized in that the base is made of a channel. 3. Chamber furnace with a roll-out hearth according to claim 1, characterized in that the bearing surfaces of the thermal shutter are made of steel sheet. 4. Chamber furnace with a roll-out hearth according to claim 1, characterized in that ceramic fiber is used as the sealing material.

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