US2087344A - Heat exchange apparatus - Google Patents

Description

July 20, 14937. A. HAssELBAcH 2,087,344

HEAT EXCHANGE APPARATUS Filed NOV. 13, 1934 :hanche-:wc tim mmm Patented July 20, 1937 YUNITED STATES HEAT EXCHANGE APPARATUS Alexander Hasselbach, Dessau, Germany, assignor to G. Polysius, Aktiengesellschaft, Dessau,

Germany, a firm Application November 13, 1934, Serial No. 752,872 In Germany November 15, 1933 Claims.

- This invention relates to heat exchange apparatus and is more particularly concerned with apparatus for the burning or calcining of cement and similar materials. It is the principal Aobject 5 of the invention to provide apparatus of this character which will improve the efficiency of conventional kilnsby utilizing a greater proportion of the heat introduced or developed in the kiln and which will deliver the material to the l0 kiln in a partly treated' or burned condition whereby the length of the kiln or the period of treatment of the material therein may be substantially lessened and a smaller quantity of fuel will suice.

It is a more specic object of the invention to provide, in combination with a kiln which may be of the usual rotary type, a device associated with the inlet end of the kiln but arranged exteriorily thereofnwithin which the material may be gas. In the preferred form of the invention this device comprises a support for the material which is mounted for rotation independently of the kiln and which is permeable to the gas, means -being provided to introduce the exhaust kiln gas above the material on the support and to withdraw the gas downwardly through the material and the support, whereby the material may be subjected directly to the action of the hot gas andl will at the same time protect the support from excessively high temperatures.

Further objects and features of the invention will b'e apparent from the following description taken in connection with the accompanying drawing, in which Figure 1 is a vertical sectional view of apparatus embodying the principles of the invention;

and

, Figures 2, 3, and 4 are sectional views of modied forms of the gas permeable support shown in Figure 1.

It will be observed that in the drawing the invention is illustrated as applied to a conventional rotary kiln a, this being the preferred embodiment of the invention. It will nevertheless be .understood that the application to other types of kiln is contemplated. A chamber d, within'which the material is subjected to preliminary treatment, is provided with a discharge chute c leading into the inlet end of the kiln, the chamber and chute being preferably stationary, conventional means being associated with the kiln and chute whereby the kiln may be rotated without the escape of gas except through the chute.

Within the chamber d is supported a drum b,

subjected tothe action of the hot exhaust kiln.

the drum having a gas permeable periphery and being preferably cylindrical in shape. The longitudinal axis of the drum is preferably disposed in a generally horizontal direction, the drum being supported, for instance, on a shaft e which may be rotated in any convenient manner. Extending through one end wall of the chamber d and drum b is an inlet chute g through which the material to be treated may be introduced into the drum.

At its lower side'the chamber d may be provided with a downwardly directed, generally conical portion f leading to a conduit i through which gas may be withdrawn from the chamber, a fan h or other suitable device being preferably associated with the conduit i for this purpose.

In View of the simplicity of the apparatus, the mode of operation will be quite apparent. The material to be treated, for instance raw cement material or the like, is introduced through the d inlet chute g, is deposited on the lower side of the gas permeable support or drum b and is gradually displaced toward the left-hand end from whence it is discharged through the chute c into the kiln a for the final burning. The hot exhaust gas from the kiln a passes' in the opposite direction through the chute c, the contraflow principle being thus employed, flows into the drum b immediately over the layer of material therein, and is drawn downwardly through the material and through the drum and discharged through the conduit z'. In this manner the material in the drum is subjected to the very high temperature of the exhaust kiln gas and heat which would otherwise be 4wasted is rendered effective for partial preliminary burning or calcining of the material. -Since the drum bis disposed exteriorly of the kiln a and since the peripheral wall of the drum is protected by the layer of material thereon, rapid destruction of i comprising a cylindrical -casing which is suitably perforated for the passage of gas, but it will be understood that a screen or wiremesh or other construction suited to the, material undergoing treatment may be employed.

Dealing nowwith Figure 2, it will be observed that exible metallic elements in the form of chains k are secured to the opposite end walls of the drum and dependent therefrom so as to sweep through the layer of material at the lower side of the drum when the latter is rotated. It will be appreciated that these chains absorb a considerable portion of the heat of the exhaust kiln gases and by passing through the material to be treated convey this heat to the material. Furthermore, it will be obvious that the chains are effective in preventing the formation of undesirable lumps of material and serve to spread the material out in a fairly thin layer and to facilitate the movement of the material from one end of the drum to the other. It will of course be appreciated that other devices of a structurally different nature but performing generally the same function as the chains specifically disclosed herein may be employed, for instance loosely disposed metallic elements or other well-known heat exchange or transmission bodies.

In Figure 3 an arrangement is illustrated in which the chains are supported at one end from the peripheral wall of the drum b at points spaced circumferentially and longitudinally thereof. In Figure 4 the chains are simply laid in the bottom of the drum. Various combinations of these arrangements of the chains are of course possible.

Having thus described the invention, what is claimed as new and desired to be secured by Letters Patent is:

1. In apparatus for effecting preliminary treatment of material to be burned in a kiln, the combination with the kiln, of a drum separate from and disposed exteriorly of said kiln and adjacent the inlet end of the kiln for rotation about a generally horizontal axis, said drum having a gas permeable yperipheral'wall affording a support for the material, means for discharging the material from the drum into the kiln and for conveying exhaust gas from the kilny into the drum, gas-tight means closely surrounding the peripheral wall of said drum above the normal level of the material therein, and means for withdrawing gas from the drum in a downward direction through the material and the peripheral wall of the drum.

2. In apparatus for making cement and similar products, the combination with a preburning chamber, of a gas permeable support Within said chamber, said support comprising a rotatable drum, the wall of said chamber closely surrounding the peripheral wall of said drum above the normal level of the material therein, a kiln ar- 'products, the combination with a preburning chamber, of a gas permeable support within said chamber, said support comprising a rotatable drum, the wall of said chamber closely surrounding the peripheral wall of said drum above the normal level of the material therein, exible heat I exchange members disposed within said drum, a kiln arranged to receive the material from said support for causing the burning of the material, said support being separate from and disposed outside said kiln, means whereby said material is delivered from the support to the kiln, and means for causing a current of hot gas to flow downwardly through said support and the material thereon to preburn the material.

4. In apparatus for burning cement and like material, the combination with a rotary kiln, of a preburning chamber separate from said kiln and disposed adjacent the kiln inlet and exteriorly of the kiln, a rotating gas permeable support for the material within said chamber, means for delivering material onto the support, means for discharging material from the support into the kiln and for conveying hot exhaust kiln gas from the kiln to a zone directly above the material on the support, means for inhibiting the passage of gas through the portion of said support not normally covered by said material, and means for withdrawing the exhaust gas downwardly through the material and the support.

5. In apparatus for effecting preliminary treatment of material to be burned in a kiln, the combination with-the kiln, of a drum separate from and disposed exteriorly of said kiln and adjacent the inlet end of the kiln for rotation about. a generally horizontal axis, said drum having a gas permeable peripheral wall affording a support for the material, means for discharging the material from the drum into the kiln and for conveying exhaust gas from the kilnr into the drum, gas-tight means closely surrounding the peripheral wall of said drum above the normal level of the material therein, means for withdrawing gas from the drum in a downward direction through the material and the peripheral wall of the drum, and chains secured to the drum and suspended therein.

ALEXANDER HASSELBACH.

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