Technical solutions on designs of the elements of the kiln channel of a circular tunnel kiln

Abstract

The kiln channel of a circular tunnel kiln for heat treatment of refractories is formed by a circular tunnel and a rotating hearth.The channel is the main element of the kiln and, in turn, consists of individual elements including the shell of the kiln channel, the circular hearth, the hearth drive, the hydraulic seal, and the lining of the kiln channel.The optimum designs of the elements are their technical solutions* [1][2][3][4][5].Shell of the Kiln Channel.The shell serves as the base of the kiln channel, the supporting portion' of the circular tunnel, and the base for the support and thrust rollers and the base of the rotating hearth, that is, it receives all of the static and dynamic loads occurring in operatin of the kiln channel.The general form of the shell and its cross section are shown in Fig. i.The basis of development of the technical solutions on design of the shell was a module system of dimensions in the horizontal plane along the axis of the kiln channel and similarity of the elements in all cross sections and along the length of the channel. As the axis of the kiln channel was taken a circumferencewith the mean diameter of the channel, the center of which is the base point.The base dimensions are the mean diameter and the length of a position.As the module was taken the length of a single position along the axis of the kiln channel, the dimension of which is expressed in linear and angular dimensions.The shell is a steel structure assembled from individual elements, the support beams I, the outer 2 and inner 3 columns, the supporting beams 4, the cross ties 5, the wall 6 and abutment 7 beams, and the housing 8. The support beams 1 and the supporting beam 4 with the outer 2 and inner 3 columns and the cross ties 5 form transverse frames and are placed on the foundation and connected to each other along the length of the kiln channel by the wall and abutment beams.The distance between the adjoining transverse frames along the axis of the kiln channel is a multiple of the length of a single position.The housing 8 is fastened to the outer columns 2 and the wall 6 and abutment 7 beams.The elements of the shell are joined by welding.The wall beams 6 are welded only in the center portion to the supporting beams 4 of the support frmmes to eliminate deformation of them under thermal actions.All of the elements of the shell are made of rolled steel.The Circular Hearth.The circular hearth is the supporting element of the rotating hearth, which fulfills the functions of creating the kiln channel and movement of the refractories in it.During operation the circular hearth is subjected to the action of alternating sign loads as the result of movements and stoppages of it and heatings and coolings.In heat treatment of refractories the frequency and intensity of the loads are significantly less than in heating of steel parts, which is responsible for the possibility of development of a circular hearth of lighter construction.A general view and the cross section of the hearth are shown in Fig. 2.The improved cir...