RU183578U1 - ELECTRIC FURNACE FOR FIRING BULK MATERIALS - Google Patents

Abstract

The utility model relates to the field of building materials, namely to technological equipment for the production of expanded vermiculite, perlite sand and other thermally activated materials. The electric furnace for firing bulk materials, contains baking sheets made of refractory material and installed in relation to each other at an angle that provides the pouring of raw materials during the firing process from one to the other, equipped with electric heaters made in the form of tapes placed under the covers on the surface of the baking sheets longitudinally mounted on a rib and mounted on heads having parallel faces; the furnace contains electric heater coating plates made of non-conductive refractory material mounted on the surfaces of the baking sheets, longitudinal grooves are made on the lower surface of the coating plates, in which electric heaters are located, and ridges and grooves are made on the lateral surfaces, which are part of one another. Effect: increase the reliability of the electric furnace for firing bulk materials. 3 ill.

Description

The utility model relates to the field of building materials, namely to technological equipment for the production of expanded vermiculite, perlite sand and other thermally activated materials.

Known electric furnace for firing vermiculite (RU No. 161281, IPC F27B 15/00, published 04/20/2016), including baking sheets with lids, baking sheets are made of refractory material and are installed in relation to each other at an angle that ensures the pouring of raw materials in the firing process with one on top of the other, and electric heaters placed longitudinally under the baking sheets and fixed on heads with parallel faces to ensure their parallel installation. Electric heaters are made with consoles and are located above the surface of the pan with a gap, while the consoles of electric heaters are suspended from the bottom of the pan on pivoting earrings mounted pivotally through ceramic insulating sleeves on rods mounted on the covers of the pan.

The common features of the claimed utility model with the analogue considered are covers and baking sheets made of refractory material and installed with respect to each other at an angle that provides for the pouring of raw materials during firing from one to the other, electric heaters are placed longitudinally under the covers and mounted on heads with parallel facets;

The specified furnace has the following disadvantage. Despite the fact that electric heaters are located above the surface of the pan with a gap, during the movement of the fired bulk material, finely dispersed particles of vermiculite and especially perlite sand adhere (burn) to the surface of electric heaters heated up to 750 ... 850 ° C and gradually form a carbon crust . This leads to a deterioration in the conditions for the removal of thermal energy from electric heaters, to their even greater heating up to 1000 ° C and more degrees, a gradual overheating, melting and burning out. And, as a result, to the failure of the furnace with its further cooling and repair associated with the replacement of burned-out electric heaters and cleaning carbon deposits of surviving electric heaters. The reliability of such a furnace, especially when firing perlite sand, is very low, its work is accompanied by frequent failures, downtime and laborious repairs.

Also known is a kiln for firing vermiculite concentrates (RU No. 2351862, IPC F27B 9/00, published April 10, 2009), including baking sheets made of refractory material and installed in relation to each other at an angle that ensures that the raw material is poured during firing from one on the other, equipped with electric heaters, located on the surface of the baking sheets under the covers and made in the form of ribbons mounted on a rib longitudinally.

Common features with the claimed utility model are covers with baking sheets; the latter are made of refractory material and are installed in relation to each other at an angle that ensures the pouring of raw materials during the firing process from one to the other, and electric heaters, made in the form of tapes, are mounted on a rib and placed longitudinally on the surface of the baking sheets under the covers.

Said furnace has the same drawback. During the movement of the fired bulk material, its finely dispersed particles adhere (burn) to the surface of hot electric heaters and gradually form a carbon crust, which impairs heat removal from electric heaters, leads to even more heating, gradual overheating, melting and burning out. And this inevitably leads to the failure of the furnace and the need for repairs associated with the replacement of burned out and cleaning the surviving electric heaters.

The prototype is an electric vermiculite kiln (RU No. 128706, IPC F27B 15/14, published May 27, 2013), which contains lids with baking sheets. The latter are made of refractory material and are installed in relation to each other at an angle that ensures the pouring of raw materials during the firing process from one to another. Electric heaters made with a variable cross section, placed longitudinally under the covers on the surface of the baking sheets and made in the form of ribbons, are mounted on the rib. At the same time, electric heaters are mounted on heads having parallel faces to ensure their parallel installation.

Common signs of the claimed utility model with the prototype are covers, baking trays made of refractory material and installed in relation to each other at an angle that provides the pouring of raw materials during the firing process from one to the other, and electric heaters placed longitudinally under the covers on the surface of the baking sheets and made in the form of tapes; in this case, electric heaters are mounted on a rib and mounted on heads having parallel faces to ensure their parallel installation.

The disadvantage of the prototype is the same as that of the analogs discussed above: when moving along baking sheets, finely dispersed particles of fired bulk material (vermiculite, perlite sand, etc.) adhere (burn) to the surface of hot electric heaters and form a deposit that impairs heat removal from the surfaces of electric heaters . This leads to a gradual overheating, melting and burning out of nichrome electric heaters, furnace failure and the need for its repair, associated with the replacement of burned out and cleaning the surviving heaters.

The objective of the claimed utility model is to create an electric furnace for firing bulk materials, which eliminates failures due to sticking or burning to the hot electric heaters finely divided particles of fired bulk material, their overheating, melting and burning.

The technical result of the utility model is to increase the reliability of the electric furnace for firing bulk materials by eliminating furnace failures due to overheating, melting and burnout of electric heaters.

The specified technical result is achieved in that the electric furnace for firing bulk materials containing baking sheets made of refractory material and installed in relation to each other at an angle that provides the pouring of raw materials during the firing process from one to the other, is equipped with electric heaters made in the form of tapes placed longitudinally under the covers on the surface of the baking sheets, mounted on the rib and mounted on heads having parallel faces, according to the utility model, additionally neighs the cover plates of electric heaters made of non-conductive refractory material, installed on the surfaces of the baking sheets, longitudinal grooves are made on the lower surface of the coating plates, in which electric heaters are located, and ridges and grooves are made on the side surfaces, which are part of one another.

During the firing process, the flow of bulk material moves along the inclined upper surfaces of the coating plates, heated to the required temperature (depending on the type and dimension of the fired bulk material, for example, 550 ... 650 ° C), heated to 750 ... 850 ° C (and, if necessary, more ) by electric heaters and poured from one baking sheet to another. In this case, the fired bulk material and its finely dispersed components do not come into contact with electric heaters, since even the gaps between adjacent coating plates are overlapped by ridges entering the grooves of adjacent coating plates.

Due to the sufficient temperature of the upper surfaces of the coating plates, vermiculite or perlite sand (or other materials) is expanded, and due to the elimination of the contact of bulk material with incandescent electric heaters, overheating, melting and burning out of electric heaters, and as a result, furnace failures, are eliminated.

Distinctive features of the claimed utility model from the prototype is that the furnace contains electric heater coating plates made of non-conductive refractory material mounted on the refractory surface of the baking sheets, and longitudinal grooves are made on the lower surface of the coating plates, in which electric heaters are located, and on the side surfaces ridges and grooves made one in the other are made.

The presence of distinctive features allows us to conclude that the claimed utility model meets the patentability condition of “novelty”.

In FIG. 1 shows a diagram of an electric furnace for firing bulk materials.

In FIG. 2 shows a baking sheet of an electric oven (in horizontal position).

In FIG. 3. shows a cross section of a coating plate with electric heaters (r is the interval between electric heaters).

The electric firing furnace for bulk materials shown in FIG. 1, contains a raw material hopper 1, a metering drum 2 and a guide tray 3. In the frame 4 of the electric furnace, there are baking sheets arranged at an angle with respect to each other, ensuring that the calcined bulk material is poured from one to another. The baking sheets are equipped with lids 5 and electric heaters 6, placed on the surfaces of the baking sheets under the covers 5. Electric heaters are mounted on the heads 7 with parallel faces.

Under the covers 5, electric heaters 6, mounted on the heads 7 (Fig. 2), are mounted on the rib and placed on the surface of the baking sheets under the cover plates 8 (Figs. 2 and 3) made of non-conductive refractory material. The heads 7 are fixed on the corner 9 with the help of pins 10 through electrical insulating gaskets 11. The corner 9 is fixed on the corner 12 of the pan frame 13 with the adjusting screw 14. At the corner 15 of the pan frame 13, an emphasis 16 is fixed that holds the refractory bricks 17 and 18 when the pan is inclined. The same emphasis 16 holds against displacement of the coating plate 8. In the coating plates 8 in the lower part there are longitudinal grooves 19 (Figs. 2 and 3).

An electric furnace for firing bulk materials is as follows. Raw material from the hopper 1 is fed by a metering drum 2 along the guide tray 3 to the surface of the coating plates 8 in the upper part of the upper baking sheet (Fig. 1). Moving under the action of gravity on the surface of the coating plates 8, heated to the required temperature (for example, 550 ... 650 ° C) heated to 700 ... 800 ° C and located in the grooves 19 of the coating plates 8 by electric heaters 6, FIG. 3, the intumescent particles of vermiculite or perlite sand are poured from one baking sheet to another, exposed to thermal radiation coming from the surfaces of the coating plates 8. In the lower part of the casing 4 (Fig. 1), expanded vermiculite or perlite sand leaves the furnace.

To compensate for the thermal expansion of the coating plates 8, a gap a is provided, and to allow extension of the electric heaters 6 when they are heated, a gap in (Fig. 2) is provided.

If necessary, change the surface temperature of the coating plates 8, using a thyristor controller (not shown in the figures), change the temperature of the electric heaters 6. So the electric furnace is adjusted to the desired temperature regime.

To reduce heat loss, the lid 5 has a thermally insulating layer, for example, of mullite-siliceous felt.

If necessary, adjust the position of the electric heaters 6 using an adjusting screw 14 having a groove. When the screw 14 is turned, the corner 9 and the head 7 with electric heaters rise or lower.

Due to the fact that the fired bulk material moves along the surface of the coating plates 8 and does not come into contact with the surfaces of the electric heaters 6, overheating, melting and burning out of the electric heaters 6 are eliminated, and as a result, furnace failures are eliminated.

This achieves the technical result of a utility model: improving the reliability of an electric furnace for firing bulk materials by eliminating furnace failures due to overheating, melting and burning out of electric heaters.

Claims (1)

An electric furnace for firing bulk materials, containing a frame in which baking sheets with frames and covers are placed, made of refractory material and installed at an angle to each other to ensure that the bulk material is poured during firing from one baking sheet to another, electric heaters in the form of tapes, longitudinally located on the surface of baking sheets under the covers, mounted on a rib and fixed by means of heads with parallel faces on the corners of the baking sheet frames, characterized in that it is provided with a plate and coatings of electric heaters made of non-conductive refractory material, mounted on the surface of the baking sheets under the covers and having flanges and grooves on one of the sides, and refractory bricks located on the frames of the baking sheets to ensure that they are held by stops, while on the lower surface the plates have longitudinal grooves in which said electric heaters in the form of tapes are located.

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