EA010712B1 - Chain for chained curtain of clinker-calcining rotary kiln - Google Patents

Abstract

The invention relates to inner-furnace heat-exchange devices used in cement industry used in cement industry, in particular to chained curtains of clinker-calcining rotary kilns. The chain in said curtains comprises round or oval links having flat surfaces and outer and inner end surfaces, the outer end surface has a shape of round cylinder surface, wherein each link in coupling areas its side surfaces with the outer end surface is embodied with lying opposite and opposite directed edges inclined at 40-50° in projection of link cross section to the plane, and the inner end surface is embodied curved.

Description

The invention relates to intrahepatic heat exchangers of aggregates of the cement industry, namely to chain curtains of clinker baking rotary kilns.

Chain curtains are a necessary element of the kilns in the cement technology of the wet production method, which serve to improve heat use, intensify heat exchange between hot gases and the calcined material. Along with this, the attachment of chains, acting as a filter, to a certain extent plays the role of a dust collector of gases passing through it in the area of wet material. Heat exchange chains, being one of the main heat engineering elements of chain curtains, largely determine the economic efficiency of the latter, depending mainly on the size of the outer surface of a unit of length and mass of the chain, based on which the diameter of the chain link and its shape are selected. It also evaluates the adhesive and cohesive properties of the sludge, i.e. sticking it to the chains and its critical viscosity, as well as the ability to break and abrasion of the granules of the material being calcined.

For chain curtains in the domestic cement industry, mainly welded (less commonly cast) chains are used, consisting of round or oval links (GOST 13237-67), having a cross section in the form of various ovals (8I 330321, 27.12.1966, 8I 450947, 12.03.1973 ). In the foreign industry, both welded and cast chains with round or oval links are used in chain curtains, in which the cross section can be made, for example, elliptical, or in the form of a figure eight, or T-shaped (V.I. Satarin and others. The cement industry abroad, Gosstroyizdat, Moscow, 1963, p. 113, I8 3427801, 18.02.1969, OB 1100831, 01.24.1968).

Known chains of welded links of round or oval shape with their relatively low price do not efficiently perform their technological purpose in furnaces - their round (or oval) section limits the heat exchange surface, forcing to increase the calculated curtain density. At the same time, such chains are not rational from the point of view of self-cleaning of sludge and preventing the formation of sludge rings, and cast chains with an elliptical link form, although more durable with hinged abrasion of links, are slightly higher than the welded chains in terms of heat and mass transfer in all zones of rotary kilns, before total in the areas of drying, heating and decarbonization of raw materials. In addition, all these chain designs do not allow to intensify the heat and mass transfer processes associated with the further expansion of the chain curtain, to the hot end of the furnace.

According to its technical essence, the analogue of the prototype closest to the present invention is a chain for a chain curtain of a clinker roasting kiln containing round or oval links with flat side surfaces and with internal and external end surfaces, of which the latter has the shape of a circular cylinder surface (I8 34424987, 06.05). 1969).

This known chain, which was used for chain curtains, especially in large-diameter furnaces in the heating and decarbonation zones, confirmed its main disadvantages: limited durability and the inability to increase the heat transfer coefficient without a significant increase in the size and weight of the links.

The objective of the invention is the creation of new designs of chains with improved strength and heat engineering characteristics at the optimum ratio "heat exchange surface - the mass of a single chain link".

This problem is solved by the fact that in a chain for a chain curtain of a clinker kiln containing round or oval chains with flat side surfaces and with internal and external end surfaces, of which the latter has the shape of a circular cylinder surface, each link around the perimeter at the interface points of its side surfaces with the outer end surface is made with opposite and oppositely directed faces with an inclination at an angle of 40-50 ° in the projection of the cross section of the link on the plane, and the inner end face The surface is curved.

In the known technical solutions are not found these distinctive features in their entirety.

The invention is illustrated by drawings, in which:

in fig. 1 schematically shows a fragment of a chain with round links;

in fig. 2 - a single circular link (plan view);

in fig. 3 is a section along A-A in FIG. one;

in fig. 4 is a section according to BB in FIG. one;

in fig. 5 is a view of section B along A-A in FIG. 3;

in fig. 6 — chain fragment in the variant with oval links;

in fig. 7 - single oval link (plan view);

in fig. 8 is a cross section along L-D in FIG. 7;

in fig. 9 is a section along d-d in fig. 6 and in FIG. 10 is a view of E in section G-D in FIG. eight.

The chain contains links of round 1 or oval 2 forms. The side surfaces 3 and 4 of each link are flat, and the inner 5 and outer 6 end surfaces are made, respectively, by curved lines

- 1 010712 nymi and in the form of the surface of a circular cylinder. Links 1 and 2 along the perimeter in the places of conjugation of their side surfaces 3 and 4 with the outer 6 end surface are made with opposite and oppositely directed faces 7 and 8. The latter have an inclination at an angle of 40-50 °. The specified interval of angles of inclination of the faces of the side surfaces is optimal when calculating the heat exchange surface of the link and its mass for the chains of the corresponding technological zone of the furnace. The ratios of the dimensions of the structural elements of round or oval links (Ό, b, b, h, k, b, γ) are given in the table.

ϋ or E AT n TO. B Have 2 ... 5 V one 0.5 ... 2 V 1 ... 2.5 V 0.1 ... 0.3 V 40 - 50 °

Chains with known forms of links and chains with forms of links made in accordance with the invention, having equal dimensions, have almost the same contact wear resistance at the junction points of the links in the chain. However, the new configuration of the outer end surface of the links allows to significantly increase their heat exchange surface (by more than 30%), which, while optimizing clinker burning, allows reducing heat loss and intensifying heat transfer from the gas flow to the material.

At the same time, the sludge film sticking to the chains is more easily separated from the surface of the links, because in the relief of the film (repeating the relief of the outer end surface of the links) there are multidirectional forces of breaking and separating from the links, which contributes to fast self-cleaning of the chains before decarbonization zone and preventing excessive deformation of the material granules.

Thus, a more developed heat exchange surface of the proposed chains using appropriate heat-resistant steels allows placing the chain curtain in the heat-stressed parts of the hot end of the furnace with temperatures up to 1100-1200 ° С, which makes these chains universal for hanging in all technological zones of the clinker-burning furnaces.

Claims (1)

CLAIM Chain for chain curtain of clinker-burning rotary kiln, containing round or oval links with flat side surfaces and with internal and external end surfaces, of which the latter has the shape of a circular cylinder surface, in which each link around the perimeter at the interface of its side surfaces with an external the end surface is made with opposite and oppositely directed faces with an inclination at an angle of 4050 ° in the projection of the cross section of the link on the plane, and the inner end overhnost is curved.