RU35422U1 - ELECTRIC FURNACE FOR CHEMICAL AND THERMAL PROCESSING OF PRODUCTS - Google Patents

Description

2003124239

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ELECTRIC FURNACE FOR CHEMICAL AND THERMAL PROCESSING OF PRODUCTS

The utility model relates to the field of heating thermal equipment and can be used for gas chemical-thermal treatment of small-sized metal billets and parts, for example, hardware, screws, etc.

A known furnace for chemical-thermal processing of products according to the patent of the Russian Federation No. 2044241, M1ZH7 F27B 5/04, 09/20/95, containing a housing in which a muffle with a heater is installed, a working chamber with a lid, to which the reaction gas supply line and the exhaust pipe are connected exhaust gas. Moreover, an acoustic oscillation generator is installed on the reaction gas supply line in the working chamber.

The disadvantages of this device include the fact that gas treatment is carried out outside the zone of the working chamber, which complicates the device. In addition, the supply of reaction gas on top of the device, i.e. where it is diverted, reduces the coefficient of its use and leads to uneven processing of the charge.

Known electric furnace according to the utility model of the Russian Federation No. 31164 IPC 7 F27B 3/08, C21D 9/00, 06/20/03 containing a furnace block with electric heaters, a working cavity, a gas pipeline, upper and lower gas distribution grids forming a gas treatment zone filled with a catalyst, while the upper gas distribution grid is equipped with a heat-insulating partition. A cover with a gas tight shutter is placed in the upper part of the furnace block, in which a heat-resistant channel for the afterburning of gaseous products of chemical-thermal treatment is made.

The disadvantages of this furnace include the heterogeneity of the treatment of the charge, since its lower layers are in contact with a gas having a higher concentration than the upper ones, since when passing through the working chamber from the bottom up, the gas activity is lost. This utility model solves the problem of ensuring uniform

chemical-thermal treatment (heat treatment in a protective atmosphere, cementation, nitrocarburizing, nitriding, etc.) in bulk cages of small-sized metal billets.

The problem is solved in that in an electric furnace for chemothermal treatment of products containing a furnace block, electric heaters, a retort forming a working chamber, lower and upper gas distribution grills located in the lower part of the working chamber and forming a cavity for placing a catalyst, connected by a gas supply to the reaction supply line gas, a cover with a gas tight shutter and an exhaust gas channel, the electric furnace is equipped with a removable cylindrical container with a blank bottom and perforated holes forged walls. Moreover, the container is installed with a gap relative to the side walls of the working chamber and the upper gas distribution grill, while a perforated pipe is connected inside the container coaxially to its side walls, connected to the exhaust gas channel, and forming an annular working area with the side walls of the container to accommodate the workpieces.

In order to simplify the removal of the cages, the blank bottom of the container is removable.

For the purpose of temperature separation of the cavity for placing the catalyst from the working chamber, the upper distribution grid is equipped with a heat-insulating partition.

In order to simplify the device, the perforated side walls of the container can be made of mesh.

In order to ensure the afterburning of the residues of gaseous products of chemical and chemical-thermal treatment directly on the furnace, the exhaust gas channel is heat-resistant.

,

2 Perforated pipe may be provided with a shutter blocking

top to bottom part of its holes.

In order to increase the uniformity of the treatment of the charge, taking into account the degree of decrease in the activity of the reaction gases, the holes on the side surface of the container can be made with an increase in their density per unit surface from bottom to top.

The utility model is illustrated in the drawing of FIG.

The electric furnace for chemical-thermal treatment of products contains a furnace block 1, in the side walls of which are installed controlled working electric heaters 2, and in the lower part - the hearth - controlled hearth electric heaters 3. Inside the furnace block 1 there is a retort 4 forming a working chamber 5. In the lower parts of the working chamber 5 are placed lower 6 and upper 7 gas distribution lattices, forming a cavity 8 for accommodating the catalyst. The cavity 8 is connected by a gas supply 9 to a line (not shown) for supplying a reaction gas, for example, hydrocarbon, and forms a gas preparation zone.

The upper part of the retort 4 is provided with a lid 10c with a gas tight shutter and an exhaust gas exhaust channel 11, which can be made of heat-resistant material.

In addition, the electric furnace is equipped with a removable cylindrical container 12 with perforated side walls and a blind bottom 13, which can be made removable. Moreover, the container 12 is installed with a gap of its side walls relative to the side walls of the working chamber, formed by the surface of the retort 4, and its blind bottom 13 with the upper gas distribution grid 7. At the same time, a perforated pipe 14 with holes 15 is fixed inside the container 12 coaxially with its side walls. the channel 11 of the exhaust gas, and forming with the side walls of the container an annular working area 16 for accommodating the workpiece 17.

3 Holes 15 in perforated pipe 14 are made to a height

the side walls of the container 12, and can overlap from above to the height of the cage, for example, by means of an additional pipe - a valve (not shown) installed inside the perforated pipe 14 with the possibility of axial movement.

Hearth electric heaters 3 are controlled by a thermocouple 18 located in the gas preparation zone, and working electric heaters 2 are controlled by a thermocouple 19 located in the working chamber 5 in the gap between the retort 4 and the container 12.

The upper distribution grid 7 may be provided with a heat-insulating partition 20.

The claimed furnace operates as follows.

Previously, the workpieces 17 are filled in the annular working zone 16 of the container 12. Rigid assembly: cover 10, central perforated pipe 14, rigid blind bottom 13 of the container 12 and the container 12 itself are placed in the working chamber 5, maintaining a gap with the side walls of the working chamber 5 and the upper gas distribution grill 7. Gas tight shutter 1 flash 10 provide sealing of the working chamber 5.

By means of a hearth heater 3 controlled by a thermocouple 18, uniform constant heating is carried out throughout the volume, to approximately 950 ° C, of the cavity 8 of the gas preparation zone where the catalyst is located. In the gas treatment zone 8, the reaction gas supplied through the gas supply 9 is decomposed without planting gas distribution channels.

In the working chamber 5, the temperature regime is maintained by working electric heaters 2 by the signal of a thermocouple 19. Due to the presence of a heat-insulating partition 20 in the upper distribution grid 7 in the working chamber 5, if necessary, the temperature regime can be set independently of the gas preparation zone 8 in the range from 500 ° C to 1100 ° C.

4 The process of chemical-thermal treatment of parts is carried out

in the following way. The heated reaction gas from the gas preparation zone 8 through the upper gas distribution grill 7 enters the gap between the side walls of the working chamber 5 and the perforated walls of the container 12. Next, the reaction gas radially flows through the cage layer to the perforated central pipe 14 through its openings 15 over the entire height of the container 12 and further to the exhaust gas channel 11. When the channel 11 is made of a heat-resistant material, an afterburning torch of residues of gaseous products of chemical-thermal treatment is formed directly in it.

Due to the fact that the concentration of reactive gas along the height of the working chamber 5 is the same, and in the radial direction of the cage 17 to the central perforated pipe 14, with a slight change in the gas concentration, its volume per unit volume of the cage increases, uniform processing of the machined parts 17 is ensured.

After carrying out the chemical-thermal treatment of parts 17, the container 12 is removed, then its dead bottom 13 is disconnected and the charge is unloaded.

The claimed electric furnace makes it possible to ensure uniform chemical thermal treatment throughout the volume of bulk cages of small-sized metal billets.

5

Claims (8)

1. An electric furnace for chemical-thermal treatment of products containing a furnace block, electric heaters, a retort forming a working chamber, lower and upper gas distribution grills located in the lower part of the working chamber and forming a cavity for accommodating the catalyst, connected by a gas supply to the reaction gas supply line, a cover with a gas tight shutter and an exhaust gas channel, characterized in that the electric furnace is equipped with a removable cylindrical container with a blank bottom and perforated side walls installed with a gap relative to the side walls of the working chamber and the upper gas distribution grill, and a perforated pipe is fixed inside the container coaxially to its side walls, connected to the exhaust gas channel and forming an annular working area with the side walls of the container to accommodate the workpieces. 2. An electric furnace according to claim 1, characterized in that the blank bottom of the cylindrical container is removable. 3. An electric furnace according to claim 1, characterized in that the exhaust gas channel in the lid is heat-resistant. 4. The electric furnace according to claim 1, characterized in that the upper distribution grid is provided with a heat-insulating partition. 5. An electric furnace according to claim 1, characterized in that the pipe is perforated to the height of the side walls of the container. 6. An electric furnace according to claim 1 or 4, characterized in that the perforated pipe is equipped with a valve that overlaps part of its openings from top to bottom. 7. An electric furnace according to claim 1, characterized in that the side walls of the container are made of mesh. 8. An electric furnace according to claim 1 or 6, characterized in that the holes on the side surface of the container are made with increasing their density per unit surface from bottom to top.