SU672218A1 - Tubular electric furnace - Google Patents

Description

(54) TUBULAR ELECTRIC OVEN

one

The invention relates to electrothermal, in particular, tubular electric furnaces of continuous resistance.

A high-temperature resistance furnace is known, comprising a heat treatment chamber in which a graphite pipe is located — a heater installed on water-cooled graphite supports — electrical leads 1.

The graphite pipe is made with rounded ends (current-carrying portions) and a thin-walled middle part (heat emission and a plot). Such a pipe configuration provides for the release of the main amount of heat in the thin-walled section, which determines the position of the final and preliminary sintering zones.

The material to be processed is loaded into graphite containers, which are moved by means of tachchatel through the pipe heater of the heat treatment chamber.

The disadvantage of this furnace is that, due to the low resistivity of graphite, for normal operation of the furnace, the current must reach large values (tens and hundreds of thousands of amperes). The application of a current of force leads to large losses of heat and electrical energy, a reduction in cos p, and the complication of electrical equipment of the installation.

With increasing electrical resistance

pipes - heaters due to thinning of its wall thickness or using a material with a higher electrical resistivity, shunting of the heat-generating section of the heater-tube located in it by graphite containers or blanks is observed. Thus, in this furnace it is impossible to reduce the magnitude of the supply current.

Also known is a tubular electric furnace containing a working chamber, a heating element and current leads. The working chamber is formed by a pipe-heater installed on water-cooled graphite supports — current leads 2J.

A disadvantage of the known furnace is that simultaneously with an increase in the electrical resistance of the heating element, its thermal conductivity decreases, the heat transfer from the heating element to the working chamber deteriorates, which

leads to a decrease in the operating temperature of the furnace and an increase in electricity consumption.

 The invention is an increase in the operating temperature of the furnace while simultaneously reducing power consumption.

This centering is achieved by the fact that the heating element is designed in the form of bends, covering the heat treatment chamber, with one current lead connected to one of the outer rings, and the other current lead connected to two to;) single rings. Such a design of the heating element makes it possible to improve the heat transfer from the heating element to the heat treatment chamber, and such a design of the current lead eliminates the possibility of shunting the heating element with products that are located in the working chamber.

FIG. I shows the oven in section; in fig. 2 same, cross section;

in fig. 3 - Zeitra, 1N portion of the heat treatment chamber of a horizontal furnace; in fig. 4 - the central portion of the heat treatment chamber of a vertical furnace.

The furnace contains a heat treatment chamber 3 enclosed in a housing 1 and surrounded by a black heat insulation 2 formed by a graphite pipe eo through a channel serving to move the graphite containers 4 contained in it. On the side of the loading end of the heat treatment chamber, the pusher 5 is dismounted, lock chamber 6 with valves 7 and 8, a lift 9 and a port 10. From the discharge end of the heat treatment chamber, there is a slotted chamber 11 with valves 12 and 13, a lift 14 and a socket 15, between the current supply sections. 16 and 17 of the chamber Ots 3 exchanged graphite rings 18-21.

The two extreme rings 18 and 19 of the furnace | eilei directly on the current lead in the first sections, 16 and 17 of the chamber 3 heat treatment. Between the rings 18 and 19 and the central ring 20 there are placed rings 21 pressed against each other, having a diameter greater than the diameter of chamber 3. A current lead 22 attached to the central ring 20, insulated from the heat treatment chamber 3 with a thermal insulation layer 2, and from the steel case 23. The outer rings 18 and 19 directly or through conductive sections 16 and 17 of the chambers1 1 3 heat treatment are connected to a current lead 22. The conductor conduit sections 16 and 17 of the working chamber 3 are electrically short-circuited to each other and connected to a grounded steel casing I.

To inspect the furnace and change the insulating scientific research institutes in the housing 1, there are 24 holes.

To adjust the co-motivation, pressed against each of the D |. rut. The zinc is tral (co-feed ring 20 can be made of separate segments, having in its shape a wedge.

With a vertical oven, the portion of the heat treatment chamber between the rings 18 and 20 may be absent.

Oven) works as follows.

The next container 4 is installed on the lift 9 and the valve 7 is closed. The lock chamber 6 is exhausted with nitrogen, after which the valve 8 is opened and the container is pressed into the channel.

Containers 4 pushes 5 periodically push to a distance corresponding to the length of one container. After the end of the heat treatment process, the containers are discharged as follows. Arrived on the lift 14, the container 4 is lowered into the power chamber 11, then the valve 13 is closed, the valve 12 is opened and the container is removed from the lock chamber 11.

In order to cool the hot containers and use the heat stored in them 1 to preheat the cold, nitrogen is fed into the furnace through the nozzle 15, which is discharged through the nozzle 10.

The voltage to the furnace is supplied to the electrical power supply 22, while the current flows from the central ring 20 through the rings 21 pressed against each other, the current-carrying sections 16 and 17 of the heat treatment chamber 3 and the conductors 25 to the grounded housing 1.

If it is necessary to change the resistance value, the pressing force of the current leads 22, the force from which is transmitted to the half rings 20, by means of which the adjustment of the pressing of the rings 21 is performed, is carried out.

Performing a heating element (1) () element in the form of rings, covering the heat-treating chamber, allows one heat transfer from the fuel cell, 1 foot of heat to heat treatment, will increase the operating temperature of the furnace and reduce energy consumption. The heat treatment chamber, containers, loading and unloading units, as well as the furnace casing have odipak potential and are fixed, which makes the furnace completely safe and does not require the use of additional extraordinary insulation of the working parts of the loading and unloading units.

(scar electric furnace, soda) of the heat; l slave (to the premier. heating and current traps, disconnected, a (: so that. for the purpose of drinking the operating temperature is not fourteen seconds) D1; ()

electrical charge, the heating element is made in the form of a switch, covering the chamber tsmmoob), and one current lead is connected to the other side of the single gauge, and the other current lead is connected to the two outer rings.

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Sources of information taken into account in the examination

1. USSR Author's Certificate No. 465271, F27 5/06, 1973.

2. Author's certificate C ((L No. 345637, F 27 D 11/02, 1969.

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