RU2157959C2 - Ring furnace - Google Patents

Abstract

FIELD: manufacture of building materials. SUBSTANCE: raw blanks with through holes are used in roasting, thus forming passages in change for effective heat exchange between heat- transfer agent and articles to be roasted. Roasted circular passage has rectangular section, 0.5 to 1.5 m in height; each chamber is equipped with sectional floor and sectional hearth which may be laid on bottom of chamber together with charge and unloaded from it together with finished articles. Structural modifications made in ring furnace make it possible to mechanize processes of charging the raw material and unloading the finished product under conditions favorable for operating personal. EFFECT: enhanced efficiency of manufacture of building materials of high quality at low consumption of heat and power; low cost of product. 3 cl, 2 dwg

Description

 The invention relates to the building materials industry, specifically to technological equipment for the production of building products.

The use case of a ring brick kiln for producing expanded clay is known. From the ability to swell clay on the press belt, blanks were formed in the form of raw brick. Without making changes to the design of the furnace, a rarefied cage was made from these blanks. Firing was carried out at 1100 ^o C and expanded clay was obtained, however, its porosity in the height of the cage was uneven (see Evorenko GI "Building Materials of Transbaikalia", Chita Book Publishing House, Chita, 1961).

 Known annular furnace containing zones of heating, firing and cooling, stationary walls and a vault. The furnace is equipped with a movable hearth and a pusher. The arch and the pusher are made in the form of a comb, forming a multi-channel system, with the heating and cooling zones located in the extreme channels, and the firing zones in the middle ones (SU 1037036, F 27 B 13/00, 1983).

 Clay tunnel expansion furnaces are known, which are continuously operating thermal installations consisting of a direct channel along a rail laid inside of which a train of trolleys with heat-resistant forms mounted on them in which the clay to be expanded is embedded is moving. There are options for laying clay directly on under the trolleys, heated from below, regardless of heating clay from above in the furnace channel. The calcined hot material moves toward the exit of the furnace, and cold air passes towards it, which, cooling the material, heats up and gets hot in the burners. In this zone, the temperature reaches a maximum. Gases, combustion products, pass into the front part of the kiln in the direction of the material to be fired - the heating zone, where trolleys with freshly loaded material are met and heated before firing. Flue gases are sucked out of the furnace with a smoke exhaust or chimney. Pushers that are hydraulic, mechanical or chain are used to move the train of trolleys in the tunnel (see A. Voznesensky, Thermal Installations in the Production of Building Materials and Products. I., Gosstroyizdat, 1958).

 The closest in terms of economy and technical essence to the claimed invention is a continuous ring furnace, invented in 1858 by Hoffmann, further improved by the author himself and other specialists (V.Ya. Yasinsky. How to burn brick in Hoffmann kilns. State ed. Of local industry M., 1939, p.31-41).

 The main element of the furnace is a closed oval annular channel with a width of 3.0 ... 5.5 m and a height of 2.5 ... 3.0 m. To open the furnace with raw material and unload finished products after firing, there are holes in the outer walls of the burning channel - walkers, which are covered with masonry for the duration of the firing, the portion of the burning channel corresponding to the distance between the two walkers is conventionally called the "camera".

 The raw material charge in the ring furnace is one of its structural parts, it creates favorable conditions for heat exchange between the brick and the gases washing it, the rational filling of the volume of the burning channel with the brick, and the uniform distribution of the coolant in the furnace create favorable conditions for the technological process. In a ring furnace, a predetermined temperature regime can be ensured when burning solid, liquid or gaseous fuels. To remove the products of fuel combustion in the middle part of the furnace there is a chimney connected to a smoke exhauster and a chimney, and each chamber is connected to a chimney by separate chimneys-eyeglasses. To separate the flue from the firing channel of the furnace, special cones are installed in the path of the gases when they exit the flue, which allow you to adjust the draft by reducing or increasing the opening of the chimney. In order to rationally use the heat of cooling chambers, they are connected to the chambers using a Schmauch channel, through which air heated by a brick cooled is moved (see Rogovoy M.I. "Thermotechnical equipment of ceramic plants", M., Stroyizdat, 1983).

 Analogs have a number of significant drawbacks that complicate and increase the cost of the process, reduce the effect of clay expansion, and therefore the quality of the products. The heat exchange between the heat carrier gas and clay in the stationary raw billets and in the embankment is slow. The trolleys of the tunnel kilns and the rail track are very metal-intensive, they work in adverse conditions, their maintenance is difficult.

 The disadvantages of the prototype include the high height of the burning channel, due to which the charge is high and there is uneven burning due to the temperature difference in height. In a ring furnace, a significant part of the work has to be done manually at high temperature.

 The invention solves the problem of using the principle, advantages and basic structural solutions of a ring furnace when creating an installation for the production of effective porous products from clay raw materials.

 The stated problem is solved by using raw billets with through holes that are laid in the cage so that the holes form channels in the cage directed along the course of the fire and serve as ways of moving the coolant. The burning channel has a rectangular cross-section at a height of 0.5 ... 1.5 m, which is formed by longitudinal walls laid on the bottom of the chamber by the hearth, made in the form of a heat-resistant carrier panel, and precast panels to overlap the chamber, laid on the longitudinal walls. Under each overlap is a load that has the ability to reciprocate vertically and be locked in the extreme upper and lower positions. The sub is made in the form of a heat-resistant carrier panel, which, depending on the technological need, can be laid on the bottom of the chamber, or removed from it together with the cage. The walls, weights and hearths facing the inside of the burning channel of the surface are coated with a material that prevents the burning products in contact with them from sticking to them.

 In FIG. 1 is a plan view schematically showing an annular furnace; figure 2 in cross section shows a burning channel.

 The annular furnace is a stretched calcining annular channel 1, bounded by two longitudinal walls 2, conditionally divided into 12 ... 36 cameras. In a cross-section, the calcination channel has the shape of a rectangle formed by longitudinal walls 2, laid on the bottom of the chamber bottom 3 and laid on the longitudinal walls by floor panels 4. Under each panel of overlapping the camera there is a load 5, which has the ability to reciprocate vertically using special lifting mechanism and be fixed in extreme upper and lower positions. The planes of the walls 2, the hearth 3, the floor 4 and the load 5 facing the inside of the burning channel 1 have a coating of material that prevents the fired products being in contact with them in a pyroplastic state from sticking to their surface 6.

 An annular furnace operates as follows. When removed from the intended for loading camera overlap 4, remove from it under 3 and lay it near the camera. On the under lay a cage of raw billets with through holes so that the holes form channels in the cage along fire and smoke. Under the hoist with the cage laid out, a lifting mechanism is installed in the chamber, which is closed by the floor panel 4 with a load 5 located under it. Heated air is supplied from the chilled chambers to the specified technological mode, then the billets are fired until they are expanded, then the load 5 is lowered and molded products. Then they are cooled according to a regime that minimizes thermal destructive changes in products. After the products are cooled, the overlap, together with the load, is removed from the chamber, underneath it is removed from the chamber, unloaded, cleaned and placed under load, the technological process is repeated in the described sequence. Despite the fact that each furnace chamber in thermal terms operates on a periodic cycle, the whole furnace as a whole, due to the movement of zones sequentially from the chamber to the chamber, operates continuously.

Claims (3)

 1. An annular furnace, including an annular channel bounded by two longitudinal walls, conventionally divided into chambers, which allows the brick to be heated to sintering temperature when burning fuel, characterized in that the calcining channel has a rectangular cross section at a height of 0.5 - 1.5 m, formed by longitudinal channel walls laid on them by prefabricated floor panels and hearths.  2. The annular furnace according to claim 1, characterized in that the under is made in the form of a plate that can be removed from the chamber for laying out the cages from raw billets, then returned to heat treatment and again removed to unload the finished products.  3. The annular furnace according to claim 1, characterized in that the surfaces of the walls, floors, and hearths facing the burning channel are coated with a material that prevents contact of the burning products from sticking to them.

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