US2231249A - Heat exchange apparatus - Google Patents

Description

Feb. M, 1941. T R, BROWN 2,23L249 HEAT EXCHANGE APPARATUS Filed June 5, 1939 Fig:

. 1N VENTOR. THG/M f?. BRO W/V @M WA4/Lw M Patented F eb. 1l, 1941 UNITED STATE PAT NT OFFCE 7 Claims.

This invention relates to an improved means for cooling materials, particularly improvements in means for removing heat from roasted ores or the like.

In certain industrial processes, solid materials in divided forms are heated or roasted as part of their processing and require subsequently to be cooled. This is particularly true in certain mining and milling operations Where ores require roasting as a step in the separation and recovery of their valuable constituents. Such -ore requires removal of some orall of the heat retained by the ore after leaving the roaster, to facilitate subsequent steps in its reduction and recovery treatment.

Various types of devices have been used for removing excess heat from roasted ores or the like, but the devices of the prior art have been limited in their eiciency by reduced surface contact of the receptacle containing the hot ore, with the cooling medium. Certain prior devices have also been limited in. their operating results by lack of provisions for properly stirring and/r tumbling the hot ore so as constantly to bring such ore in Contact With or in proximity to surfaces of the ore container that are adjacent the cooling medium.

It is a principal object of the present invention to provide an improved means for removing excess heat from ore or the like, with an unusually high degree of efliciency.

Another and more particular object of the invention is to provide a cooler or heat exchange apparatus having passages for the ore, Which present a relatively large surface area to a cooling medium.

Still another object is to provide such passages in a heat exchange device that will hold the material being cooled in heat-exchanging proximity to a cooling medium for a relatively long period of time.

A still further object is to provide rotary passages for the reception of material to be cooled, having noncircular cross sections of a particular shape inv order to subject the material therein to a desirable tumbling and rolling action While it is being advanced therethrough.

A still further object is to provide in a device of this character, means for supplying and regulating a cooling medium. i

@ther objects and advantages reside in details of design and construction which will be more fully disclosed in the following description and in the drawing vvherein` like parts have been similarly designated and in which:

(Cll 257-90) Figure l is a plan view of a cooler or heat exchange device that embodies the present inventive concept and is Well adapted to perform the present improved method;

Figure 2 is a central longitudinal section of l5 the same;

Figure 3 is a cross sectional vievv taken along the line 3 3 of Figure 2`; and

Figure 4 is a cross sectional View corresponding to Figure 3 and illustrating a modified form of 'l0 the present invention.

The improved apparatus embodying the present inventive concept includes means for subjecting divided materials to a progressive movement through or along heat-conductive surfaces l5 contacting a fluid heat exchange medium, While simultaneously rotating such surfaces to intermittently submerge the same into the heat exchange medium in a cyclic movement. By virtue of this complete submersion of such surfaces, 20 heat exchange is effected in at least two directions. In addition to the progressive movement and the rotation, the material is subjected to unsymmetrical tumbling or rolling movement so as constantly to present different surfaces of 25 the material toward the heat exchange medium.

While the present inventive concept could 'oe embodied in various types of apparatus, a typical reduction to practice is illustrated and will be explained in detail in order to provide a clearly 30 understandable disclosure. The present exam.- ple is not intended to express or imply any limitation to the scope of the present invention.

Referring first to Figure 1, reference character I2 denotes a tank-like container for the cooling 35 medium. The tank preferably is made of ooncrete and the preferred cooling medium is Water as indicated at I3. A cylindrical housing or shell I 4 is provided with hollow trunnions I5 and I6 which are journaled in suitable bearings 40 at opposite ends of the tank I2 to provide for rotation of the shell I4 Within said tank and at least partially submerged in the cooling medium I3. The trunnions are preferably provided with y packing glands adjacent their respective bear- 45 ings in order to prevent the cooling medium from escaping therealong.

The shell may be rotated through the nterinediary of a gear Il thereon, which in turn is driven by a prime mover such as motor I8, 50 through suitable speed reducing mechanism. Preferably, the shell I4 should be rotated at relatvely low R.. P. M. in order to avoid any centrifugal action upon the material therein that is being cooled.

The water or other liquid cooling medium may conveniently be supplied from any source not shown, through the perforated pipe I9 positioned above the tank I2 and the shell I4 The cooling medium may be sprayed through the perforations of the pipe I9 downwardly onto the rotary shell I 4, The cooling medium accumulates in the tank I2 up to a level that may be optionally governed by an overflow Weir 20.

In the form of the invention illustrated in Figures 1, 2 and 3, the interior of the cylindrical housing or shell I4 is sub-divided into three longitudinal passages indicated respectively at 2 I, 22 and 23. The ends of these passages are defined by plates 24 and 25, which close the space between said passages, leaving both ends of all said passages open into the respective end zones 26 and 21 within the shell I4. A series of openings Illa through the cylindrical walls of the shell I4 provide passages whereby the liquid cooling medium I3 may freely enter and leave the space between the passages 2| 22 and 23 that is closed by end plates 24 and 25. No cooling medium whatever is permitted to enter passages 2|, 22 and 23 at any place.

As illustrated, the cross sectional shape of each passage 2|, 22 and 23 is generally elliptical and is therefore effective for improved results as will be hereinbelow set forth. Each passage 2 I, 22 and 23 is provided with helical or angular flights indicated generally by reference character 28 so that material may be longitudinally advanced as a result of rotation of the shell I4.

The feed trunnion I5 may be provided with a feed chute 29 and when desired, a stationary end plate may be arranged around the chute in abut ting relation to trunnion I5. The discharge trunnion I6 is preferably provided with helical flights 30 lto facilitate discharge of material therefrom. The discharge end of the shell I4 is provided with a cone 3| to facilitate discharge of material from the passages 2|, 22 and 23 into and through discharge trunnion I6.

Operation In use, divided ore or other material having excess heat to be removed, is fed through feed chute 29 into end zone 26 within the shell I4, while said shell is being rotated at a relatively low speed by the mechanism hereinabove set forth. Ore or other material being cooled, as represented by reference character 32, advances into the longitudinal passages 2 I, 22 and 23, particularly as they move in rotation to their lowermost positions. Upon entrance into said passages, the flights 28 therein tend to advance the ore or other material, longitudinally of the shell I4 as indicated generally by arrow 32.

By referring to the passages 2 Ia. and 22a of Figure 4 and the passages 2|, 22 and 23 of Figure 3,it will be seen that as these passages undergo angular movement due to the rotation of the shell I4, the material 32 therein will be thoroughly rolled and tumbled constantly to present different portions thereof to the inner surfaces of the passages. Obviously, the material of which the shell I4 and the passages 2 I, 22 and 23 are constructed, preferably is heat-conducting metal such as sheet steel.

The entire exterior surface of each passage 2|, 22 and 23 is completely immersed in the cooling medium I3 at each revolution of the shell I2, as best illustrated in Figure 3. By the combined effects of the total immersion of the' entire exterior surface of each passage 2| 22 and 23, together with the improved rolling and tumbling action of the material therein, extremely high efficiency in heat exchange is effected.

Heat is conducted from the material 32 that is in the passages` 2|, 22 and 23, through the walls of said passages inclusive of portions of the walls of the cylindrical shell I4, into the cooling medium I3, which constantly may be renewed by controlled input and overflow thereof. The particular elliptical cross sectional shape of each passage 2 I 22 and 23 so rolls and tumbles material therein that different portions thereof are constantly being brought into contact with or in proximity to the cooled surfaces of the passages.

The sprays projected from pipe I9 onto the rotary shell I4 may be dispensed with if desired. They are not essential to good cooling results with the present invention, but under some circumstances, they are desirable. Obviously, water sprayed upon the rotating shell I4 absorbs heat therefrom both in equalizing the temperature of the shell with that of the coolant and also by evaperation of the water from the outside surface of the shell, rendering some of the heat latent.

Means other than the perforated conduit I9 may be used for renewing the supply of water in the tank I2. Under some circumstances, the body of water I3 in tank I2 may remain static but ordinarily an input and an overflow are to be preferred.

As the material in the passages 2|, 22 and 23 advances longitudinally thereof, it is nally discharged through discharge trunnion I6 for further processing` The percentage of heat removed from the hot ore or other material being cooled, may be varied within reasonable limits by the temperature of the coolant and by the speed of rotation of the shell I4. Obviously, the slower the speed of rotation of the shell, the -greater will be the heat exchange. The buoyant effect of the liquid in tank I2 helps to Sustain the weight of the shell I4 and its contents, thus relieving the pressure in the bearings. By optionally governing the depth of the liquid in the tank by relative coordination of the fluid input and the fluid discharge at weir 26, this buoyant effect upon the shell .I4 may be optionally controlled and the exchange of heat between the shell I4 and the uid body may be varied within reasonable limits.

M o difi cations The modified form of the present invention as illustrated in Figure 4, is generic to the above outlined construction and operating principle, but only two longitudinal passages are sub-divided along the interior o-f the rotary shell I4 as indicated at 2Ia and 22a. The cross sectional shape of passages 2|a and 22a is similar to that of passages 2|, 22 and 23 hereinbefore fully described, and they are provided with internal flights preferably on opposite interior surfaces, to move the ore progressively from the feed end to the discharge end thereof. Obviously, any desired number of longitudinal passages may be provided as desired, those illustrated merely being preferred examples.

In all forms of the cooler, the heat exchange is a function of the area of the heat exchange surfaces, a function of the rolling and tumbling of the material in the cooler, and a function of the length of time the material is in the cooler. The temperature, depth, nature and circulation of the coolant, obviously, are other factors. 'The apertures |4a through the cylindrical walls of the rotary shell I4 also permit circulation of atmospheric air into and through the space between the various longitudinal passages. Some heat is absorbed and dissipated by such circulation of air, and the liquid coolant adhering to the interior surfaces may partially be vaporized by coming in contact with the atmosphere thus to further facilitate absorption of excess heat.

The stated objects of the present invention are fully accomplished by the apparatus herein illustrated and described, and While this specification discloses preferred means for reducing the present invention to practice and a preferred ernbodiment of the invention, changes may occur to those skilled in the art and may be made within the scope of the appended claims, without departing from this inventive concept.

What I claim and desire to secure by Letters Patent is:

1. Apparatus of the character described comprising a tank for a cooling liquid, a rotary shell at least partly submerged in the cooling liquid, heat-conductive walls dividing the interior of the shell into a plurality of spaced pas-sages having angular extremities in cross section to impart a tumbling action to matter therein during rotation of the shell, means for feeding loose material to be cooled to the respective passages, and means for inducing a progressive movement of the tumbled material therethrough, there being openings in the shell communicating with the space between the passages, said openings being substantially restricted whereby liquid entering through said openings is carried up and circulated across said passage-defining walls during each revolution.

`2. Apparatus of the character described comprising a tank for a cooling liquid, a rotary shell at least partly submerged in the cooling liquid, heat-conductive walls` dividing the interior of the shell into two spaced passages having angular extremities in cross section to impart a tumbling action to matter therein during rotation of the shell, means for feeding loose material to be cooled to the respective passages, and `means for inducing a progressive movement of the tumbled material therethrough, there being openings in the shell communicating `with the space between the passages, said openings being substantially restricted whereby liquid entering through said openings is carried up and circulated across said passage-dening walls during each revolution.

3. Apparatus of the character described comprising a tank for a cooling liquid, a rotary shell at least partly submerged in the cooling liquid, heat-conductive walls dividing the interior of the shell into three spaced passages having angular extremities in cross section to impart a tumbling action to matter therein during rotation of the shell, means for feeding loose material to be cooled to the respective passages, and meansI for inducing a progressive movement of the tumbled material therethrough, there being openings in the shell communicating with the space between the passages, saidopenings being substantially restricted whereby liquid entering through said openings is carried up and circulated across said passage-defining walls during each revolution.

4. Apparatus of the character described comprising a tank for a cooling liquid, a rotary shell at least partly submerged in the cooling liquid, heat-conductive partitions dividing the interior of the shell into a plurality of elliptical materialconducting passages having angular extremities in cross section to impart a tumbling action to matter therein during rotation of the shell, means for feeding loose material to be cooled to the respective passages, and means for inducing a -progressive movement of the tumbled material therethrough, there being openings in the shell communicating with the space between the passages, said openings being substantially restricted whereby lquid entering through said openings' is carried up and circulated across said passagedefining walls during each revolution.

5. Apparatus of the character described comprising a tank for a cooling liquid, a rotary shell at least partly submerged in the cooling liquid, heat-conductive partitions dividing the interior of the shell into a plurality of non-circular material-conducting passages having angular extremities in cross section to impart a tumbling action to matter therein during rotation of the shell, means for feeding loose material to be cooled to the respective passages, and means for inducing a progressive movement of the tumbled material therethrough, there being openings in the shell communicating with the space between the passages, said openings being substantially restricted whereby liquid entering through said openings is carried up and circulated across said passage-defining walls during each revolution.

6. Apparatus ofA the character described comprising a tank for a cooling liquid, a rotary shell at least partly submerged in the cooling liquid, heat-conductive walls dividing the interior of the shell into a plurality of spaced passages having angular extremities in cross section to impart a tumbling action to matter therein during rotation of the shell, means for feeding loose material to be cooled to the respective passages, and means for inducing a progressive movement of the tumbled material therethrough, there being a lengthwise extending row oi openings in the shell communicating with the space between the passages, said openings being substantially restricted whereby liquid entering through said openings is' carried up and circulated across said passagedening walls during each revolution.

7. Apparatus of the character described oomprising a tank for a cooling liquid, a rotary shell at least partly submerged in the cooling liquid, heat-conductive walls dividing the interior of the shell into a plurality of spaced passages having angular extremities in cross section to impart a tumbling action to matter therein during rotation of the shell, means for feeding loose material to be cooled to the respective passages, and means for inducing a progressive movement of the tumbled material therethrough, there'being rows of openings in the shell communicating with the space between the passages, said openings being substantially restricted whereby liquid entering through said openings is carried up and circulated across said passage-defining walls during each revolution.

THOMAS R. BROWN.

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