US2836903A - Slurry heat exchanger - Google Patents

Description

June 3, 1958 N, E, ANDERSEN 2,836,903

SLURRY HEATr` EXCHANGER Filed Jan. 16, 1957 FG. I

INV NTOR United States Patent O SLURRY HEAT EXCHANGER Niels Edvard Andersen, Copenhagen-Valley, Denmark, assignor to F. L. Smidth & Co., New York, N. Y., a corporation of New Jersey Application January 16, 1957, Serial No. 634,481

Claims priority, application Great Britain January 23, 1956v 4 Claims. (Cl. 34-199) This invention relates to apparatus for heating raw material slurry by means of hot gases preliminary to a nal heating operation, as, for example, the burning of the slurry in the wet process of cement manufacture. More particularly, the invention relates to an improved form of known slurry heating equipment, which is more durable and less liable to damage from stresses arising from temperature differences and the weight of the equipment than the constructions previously used.

One known form of apparatus for heating raw material slurry by hot gases comprises a tubular shell or drum mounted for rotation on an axis, which is horizontal or approximately so, and has its interior divided into compartments overlapping lengthwise of the drum. The compartments are open at opposite ends and each one is defined by an end wall transverse to the shell axis and by chambers, each formed of a pair of side walls lying between the end walls. The chambers are connected rigidly at their inner ends adjacent the shell axis. The chambers may contain charges of loose bodies and, in their passage through the shell, the slurry and hot gases pass in opposite directions through the chambers from one compartment to the other. The apparatus may be constructed as a separate unit supplied with hot gases from the kiln, in which the nal heating operation is performed, or the apparatus may be combined with the kiln with the compartments formed near the upper end of the kiln.

The slurry heating apparatus described is effective for its intended purpose but, when the shell is rotated during the heating operation, its cross-sectional shape changes continuously and the rigidly connected chambers are subjected to varying stresses, which cause deformation and ultimate damage to the chamber walls.

The present invention is, accordingly, directed to an improved form of the slurry heating apparatus comprising a shell with compartments formed by chambers, as described, and the new apparatus is so constructed that damage to its structure from stresses arising from heating and the weight of the shell is avoided. In the new apparatus, each chamber is rigidly secured to the shell wall and the inner ends of the chambers are formed to resist distortion. The compartments within the shell are then formed by end walls transverse to the shell axis, the chambers, and flexible connections between the inner ends of the chambers, which complete the definition of the compartments and permit such rotative movement of the inner ends of the chambers as is necessary to prevent damage to the structureY under stresses resulting from temperature changes and the Weight of the shell.

For a better understanding of the invention, reference may be made to the accompanying drawing, in which:

Fig. l is a view in elevation with parts broken away of one form of the apparatus of the invention; and

Fig. 2 is a sectional view on the line 2-2 of Fig. l.

The apparatus has been illustrated as installed in the upper end of a rotary kiln, which comprises a tubular shell 1G having tires 'li supported on rollers l2 with its 2,836,903 Patented .lune 3, 1958 ICC ends lying within upper and lower hoods 13, 14, respectively. The hood 13 has an outlet 15 for hot gases and the slurry to be heated is introduced into the end of the kiln through the upper hood 13 by a pipe 16. The kiln is tired by fuel fed through a burner pipe 17 projecting through the lower hood 14 and into the kiln and the burned product discharged into hood 14 is disposed of in any of the usual ways, as, for example, the hood may have a discharge opening near its lower end, through which the material passes to enter a cooler, as shown in the United States patent to Vogel-Jorgenson 2,275,116, issued March 3, 1942, or to fall upon a surface leading to a conveyor.

Near its upper end, the kiln is subdivided into compartments 1S, 19, and 20, which overlap lengthwise of the vkiln, the compartments 18 and 19 being of quadrant cross-section and the compartment 2t) being made up of two sub-compartments 20a, 2Gb of quadrant cross-section connected at the axis of the kiln. The compartments 1.3 and 19 are closed at their upper ends by Walls 21, 22 and the sub-compartments 20u, 2Gb of compartment 2S are closed at their lower end by walls 23, only one of which is shown.

The compartments are further deiined by chambers 2d, which include side walls 24a lying parallel to a radius of the kiln shell and on opposite sides of the shell axis. The chambers are closed at their ends by one or the other of walls 21, 22, or 23 and each chamber extends through an opening in the kiln and has flanges Zdb, by which the chamber is rigidly secured to the shell. At its inner and outer ends, each chamber has end closures 25, 26, which are semi-cylindrical to provide rigidity. The outer closure 25 has a removable door 25a through which a charge 26a of loose bodies may be introduced into each chamber. The portions of the side walls 24a of the chambers, which lie within the kiln shell, have apertured sections formed in any convenient manner as by spaced rods 2de.

In the construction illustrated, there are four chambers 24 arranged in pairs with the members of each pair lying diametiically alignedacross the kiln and the members of the two pairs lying at right angles to each other. To complete the definition of the compartments, the inner end closure of each chamber 24 is connected by a flexible connection 27 to a chamber of the other pair lying at right angles to the lirst.

ln the operation of the apparatus, the slurry introduced into the upper end of the kiln through the pipe 16 runs down the kiln and enters the sub-compartments 29a, 2012 of compartment 20 through the upper open ends thereof. As the kiln rotates, the slurry passes through the apertured sections of the chambers defining the sub-compartments and coats the loose bodies, if any, in the chambers. At the same time, hot gases traveling up the kiln iow into the lower ends of compartments 18, 19 and enter the chambers defining those compartments as the kiln rotates. rl`he gases and slurry pass through the chambers in opposite directions, so that a good heat transfer eect is obtained.

During operation, the cross-sectional shape of the kiln shell supported on the rollers continuously varies under its own weight and the shell is exposed to varying amounts of heat, so that it undergoes temperature changes leading to further changes in shape. In the present apparatus, stresses which develop as a result of the changes in shape of the shell, do not atleet the chambers, since they are rigidly mounted at their outer ends in the kiln shell and move with it and, at their inner ends, are flexibly connected to adjacent chambers. As a result, damage to the chambers resulting from changes in shape of the kiln shell are avoided.

I claim: Y

l. Apparatus'for heatingtslurryrtby means of gases, which Vcomprisesa tubular shell mounted for rotation with itsVV axis approximately horizontal, Ymeans for feeding slurry into the shell at onev end, means for supplying hot Ygases to the shell at the other end, the heated slurry 1 issuing from the shell at the end to which the gases are` supplied, partition means dividing the interior of the Y shell into. at least two compartments open at opposite ends and overlapping lengthwise of the shell, tlte:pz1rtiY tion means including end Walls transverse to the shell axis andY closing opposite ends of the compartments and at least two'pairs'rof spaced side walls connecting the end a walls, the' side walls of each pair being'rigidly secured to the wall ofthe shell and having a closure at their inner endsgand apertured sections within the shell, the' side Walls, end closures andend walls deriing chambers,

*Y through Vwhich thev gases vandslnrr-y pass in opposite, di-

rections in passing between compartments, aV charge of loose bodies'in each compartment, and flexible connect- 0 ingVmeansV-between the inner ends ofthe chambers and Y partly dening the compartments. u

12,836,903 e it 2. The' apparatus of 'claim' 1,v iri which the chambers t `are in diametrically aligned pairs with their inner ends.

lying on opposite sides of the shell axis and the inner end closures are semi-cylindrical. K i

3` The apparatus of claim V2, Vin which there are two pairs of chambers and the 'innerend of each chamber'is connected to theinnerrend of a chamber of the other pan'. Y

4. The apparatus of claim l, in which thehside Wallsof Y AndersenA V MarflZ, 1957 FOREIGN PATENTS V86,930 Ysweden Y May 2o, 1936

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