US2218476A - Rotary cooler - Google Patents

Description

Oct. 15, 1940. R C. NEWHOUSE 2,218,476

ROTARY COOLER Filed July 5, 1940 2 sheets-shawl Oct. 15, 1940. R Q NEWHQUSE 2,218,476

ROTARY COOLER Filed July 5, 1940 2 Sheets-SheetZ Patented ct.`15, 1940` e UNITED STATES RoTAnY oooLE-R Ray C.- Newhouse, Wauwatosa, Wis., assignor tol VAllis-Chalnlers Manufacturing Company, Milwaukee, Wis., a corporation of Delaware Application July 5, 1940, Serial No. 343,935

16 Claims.

This invention relates generally to cooling apparatus and more particularly tothe construction and operation of rotary cooling apparatus adapted for use in cooling iron oxide, cement clinker, etc., hereinafter referred to as clinker.

The cooling of clinker with apparatus of this Y type is generally effected by passing air through `the interior of the rotary cooler in a counter flow direction with respect to the travel of the clinker therethrough. The cooling airwhich is heated in passing through the cooler is either all discharged into the usual kiln connected with the clinker inlet end of the cooler or a `portion of the air after leaving the cooler -is discharged into the kiln and the remainder is discharged to'at- Inosphere through an independent stack. 'Ihe usual practice is to effect a compromised con-` struction which dispenses vwith the use of an independent stack, but which necessitates employing far too much air for good combustion eiciency and not enough air for the desired degree of cooling. n

The discharge of all of thecooling air into the kiln results in either a great excess of air in the kiln and inefficient combustion or an-insufcient cooling of the clinker. For example, if the quantity of air normally required for cooling purposes is reduced so as to be commensurate with that required for efficient combustion within thekiln, the clinker is insufficiently cooled since the relatively small quantity of air required for eflicient combustion within the kiln is quickly heated sufciently upon entering the cooler to rei duce, to an undesirable degree, the difference in temperature between the air and the clinker to be cooled thereby. The air normally required for cooling purposes leaves the clinker inlet end of the cooler at a temperature of -a few hundred degrees F. and if all of this air enters the kiln, the ring rate must be materially increased in order to offset the cooling effect of the great excess of relatively cool air entering` the kiln, far

too much air is present for good combustion eff ficiency, andthe heat imparted tothe air in passing throughthe kiln is wasted since the air upon leaving the` kiln is discharged directly to atmosphere through a suitable stack structure. e

The division of the heated cooling air leaving the clinker inlet end of the cooler between Han ai independent stack and the kiln does avoid introducing an undesirable excess of air into the kiln, but the overall efficiency is not greatly `improved since the major portion of the air which has been heated to a temperature of few hundred degrees t? F. is wasted by being discharged through the 'stack to atmosphere, and the relatively smallpor- `tion of this air which enters the kiln is not heated when; it leaves the cooler to a temperature conducive to good combustion eliiciency andtherefore requires further `heating within the 5 clinker discharge or ringend of the kiln. More--` over, there is not a sufficient diiference between the temperature of the air and the clinker at the f clinker inlet end of the cooler to effect a sudden cooling or a chilling of the clinker at this point which is necessary in connection with the clinkering and cooling of iron oxide and similar substances in order to avoid overheating and damage to the clinker inlet end portion of the cooler.

An object of this invention is to provide an improved rotary coooler and kiln arrangement.

Another object of this invention is to provide an improved rotary cooler and kiln arrangement which is efficient and which adequately vcools the clinker without introducing excess air into the kiln.

Still another object of this invention is to provide an improved rotary cooler construction. Still another object of this. invention is to providel an improved arrangement for Vflowing air through a rotary type cooler in order to improve the eiiciency of the cooler.

Still another object of this invention is to pro- *vide an improved rotary cooler construction in `that an intermediate portion of the cooler embodies a novel and improved correlation of air passage and clinker conveying means. y

A further object of this invention is to provide an improved rotary cooler construction in that an intermediate portion ofthe cooler is provided with a partition means operable to prevent a continuous iiow of air throughout the length of the cooler and with an enclosed clinker conveying means operable to convey the clinker through said partition means;

The invention accordingly consists of the various features of construction, combinations of elements and arrangements of parts as more fully set forth in the appended claims and in the detailed description, in which: v 45 Fig. 1 schematically illustrates a rotary clinker cooler and kiln arrangement embodying the invention;

Fig. 2 is a detail view, partly in section, schematically illustratingthe arrangement of the enclosed clinker conveying and air withdrawal means;

Fig. 3 is a transverse section taken on line III- III of Fig. 2 with the clinker conveying means 55 omitted to better show the arrangement of the air withdrawal openings;

Fig. 4 is an axial perspective View of the interior of a section of the cooler taken on line IV--IV of Fig. 2;

Fig. 5 is a partial sectional View taken on line V-V of Fig. 4;

Fig. 6 schematically illustrates a modified rotary clinker cooler and kiln arrangement which also embodies the invention; and

Fig. 7 is a detail view, partly in section, schematically illustrating the arrangement of the enclosed clinker conveying and air Withdrawal and admission means shown in Fig. 6.

Referring to Fig. 1 it is seen that the arrangement which is particularly adapted for clinkering and cooling iron oxide and similar materials comprises an inclined rotary clinker cooler l, a kiln 2, a firing hood and clinker receiving means 3 for directing the hot clinker discharged from thekiln into the adjacent open end of the cooler lI, an air withdrawal means 4, a burner pipe 5,

a secondary air conduit 6, and a cooling air supply pipe 1.

The cooler i, which is supported for rotation about its longitudinal axis by means of the axially spaced supporting roller structures 8 and which is slowly rotated on said supports by means of a driving motor (not shown) yopera-` tively connected with the usual annular gear 9, includes, asbest shown in Figs. 2 4, inclusive, an intermediate portion provided with an annular series of circumferentially spaced air Withdrawal openings i@ and an enclosed clinker conveying means il. y

Acombined Astack and casing structure i2, which encloses the said intermediate portion of the cooler, is provided with a partition i3 dividing the interior of the stack and casing structure above the cooler into two upward extending ducts or passages tl and i5 which merge into a common passage prior to reaching the top oi the stack. The top portion of the stack is provided with a draft regulating damper i6. A blower l'l has its inlet i8 operatively connected with the v,duct l5 and its outlet t9 operatively connected to discharge the air withdrawn from the duct l5 through a fuel and air mixing device and through the secondary air pipe'. A

4suitable fuel is supplied to the mixing device 20 which is connected with the burner pipe 5, through a pipe 2l and the mixing device 2d and the pipe 5 are arranged in parallel flow arrangement with respect to the secondary-air pipe 6. Valves 22 are provided for separately varying the iioW of primary air to the mixing device 2t and the iiow of secondary air through the pipe The partition I3 is provided with a valve means 23 for increasing the quantity of relatively cool air which passes from the intermediate zone, through the openings lll and into the duct l5 which in turn permits the highly heated air from the clinker inlet end of the cooler, which has already been tempered to some degree in the said intermediate Zone by mixing with some of the relatively cool air coming from the clinker discharge end of the cooler, to be further tempered if necessary to the desired degree before enteringthe fan il. In this connection, it is preferable that the arrangement be such that, under normal conditions, the highly heated air from the clinker inlet end of the cooler be tempered suilcientlyin the said intermediate Zone to prevent overheating and damage to the blower and to'prevent preignition and burning of the combustible mixture within the mixing device and/or the burner pipe 5. However, in order to permit a variable tempering of the air within the duct i5 which may be necessitated due to Variable draft conditions, the provision of means such as the valve means 23 or any other functionally equivalent apparatus is desirable.

The enclosed clinker conveying means l l comprises a pair of axially spaced transversely disposed clinker retaining rings 24 defining therebetween a zone in which is disposed the air withdrawal openings it and a plurality, three in this instance, of circumierentially spaced closed clinker conveying tubes 25 of helical form which extend through said zone adjacent the inner surface of the cooler and through the clinker retaining rings 24. The inlet end portion of each tube 25 after passing through the partition nearest the inlet end of the cooler coacts with the outer surface thereof with respect to said Zone and with the inner surface of the clinker cooler, as best shown in Figs. 4 and 5, and forms therewith an enlarged inlet or scoop portion 25. The discharge end portion of each tube 25 after passing through the partition nearest the discharge end of the coolei` terminates closely adjacent the outer surfacethereof with respect to said zone, Vas best shown in Figs. l and 2. No enlargement of the discharge end of the closed clinker conveying tube is necessary.

The hot clinker entering the cooler moves slowly toward the clinker retaining ring 24 which is nearest the inlet end of the cooler and upon reaching this ring is scooped into the enlarged inlet portion 26 of the tubes 25 due to the rotation of the cooler. The inclination and rotation of the cooler and the helical formation of the tubes causes the clinker to thereafter pass through the tubes from which it is discharged at a point immediately rearward of the partition 24 which is nearest the discharge end of the cooler. The axially spaced rings 2d function to prevent unconned clinker from entering the Zone intermediate the said axially spaced rings and the only clinker entering the said Zone and passing therethrough is that which is confined Within the closed clinker conveying tubes 25. rlhe rate at which the clinker moves axially through the cooler is primarily dependent upon three factors, namely, (l) the inclination of the cooler, (2) the speed at which the cooler rotates, and (3) the type of clinker conveying means employed; i. e., the interior surfaces of rotary coolers are usually provided with clinker impelling projections or the like which have been omitted from the disclosure in the interest of simplicity. Consequently, the annular retaining rings 24 and the closed clinker conveying tubes 25 must be so spaced and dimensionecl, taking into consideration the above mentioned three factors, that the clinker does not pile up in front of the clinker retaining ring nearest the inlet end of the cooler and flow over this ring and into that portion of the cooler which is intermediate the axially spaced retaining rings 24 and which contains the air withdrawal openings I0. The proper arrangement and the dimensions of the air withdrawal openings IQ, the retaining ringsy 24 and the conveying tubes 25 are purely a matter of design which can be readily determined for any particular application by any one skilled in the art and further details in this connection or the dimensions actually used in a particular application are not deemed necessary for a complete understanding of the present invention. l

rIhe cooling air which enters the cooler through the open clinker discharge end thereof and that which enters the inlet end of the cool-er through the pipe 'I is caused to flow toward and into the zone which is intermediate t-he said :axially spaced retaining rings 2d land out through the :air withdrawal openings It :therein by the action of the stack structure I2 and by the opera-tion of the blower il. The ilow of lair into the cooler Ithrough Ithe pipe l, the primary function of which is to effect a sudden cooling or a chill-ing of .the incoming clinken may be effected entirely by the action lof the stack structure I2 and operation of the blower l 1 or if desired, this action may be supplemented lby .asecond blower (not shown) arranged to discharge air into the pipe l.

The simultaneous intro-duction of unheated air into the opposite ends ofthe cooler yand the withdrawal of the heated cooling air from a common zon-e intermediate the said ends effects a sudden cooling or chilling of the -clinker -as it enters the cooler thereby preventing *overheating and damage to the clinker inlet end of the cooler. 'The cooling air entering the clinker inlet end of the cooler becomes highly heated by the time it reaches the intermediate zone containing the air Withdrawal openings I6. Therefore some degree of tempering is usually necessary as previously mentioned in order to avoid loverheating and damage to the blower l1 and to prevent preigniton within the mixing device 2l] and/or burner pipe 5.

The tempered I'air which is withdrawn from the duct I5 by the blower VI is used as primary air in forming `a combustible mixture which is discharged through the burner pipe 5 land is burned within the kiln 2 :and las secondary lair which is discharged through the pipe Ci .and into the kiln 'to support `and complete .the combustion of the fuel and air mixture introduced .through the burner pipe 5. The quantity of secondary air is regulated by the valve 22 in the pipe E and also by the stack damper I6, the position oi which will also vary to some extent :the quantity of .tempered .air withdrawn lfrom the duct I5 in the stack structure I2 by the blower Il. rlhis ar- -rangement permits la proper regulation of the quantity oi primary and secondary air discharged into the kiln, which in turn permits the quantity of excess :air in the kiln to `be reduced tothe minimum commensurate withefhcient combustion under all operating conditions. The quan-- tity of air passing through the kiln is always a minimum and therefor-e the quantity of `highly heated ai-r which is discharged from the kiln through .the usual stack structure (not shown) and wasted is also -a minimum. Consequently, the overall efficiency of the disclosed rotary clinker cooler land kiln arrangement is materi- Ially increased. l l

Referring to Figs. 6 .and `'7, in which like numer als :are used to designate the same or similar parts, it is seen that this m-odincation, which is particularly adapted for clinkering `and cooling cement and similar material-s, differ-s from the arrangement shown in Figs. `l5, inclusive, in that .the lcooling air supply pipe 1, the stack partition I3, and the valve means 23 are omitted; in that cooling air is admitted to the clinker inlet end portion of the cooler I through an annular series of circumferentially spaced air inlet openings 2'! and flows forward through the clinker inlet end portion of the cooler, then into the er conveying tubes 25 which are also of helical form and arranged as described in connection with Figs. 1 5, inclusivegextend in sealed relation through the partition 28 so as toV prevent lair from flowing throughout fthe entire length of the cooler; and in that the combined stack and casing structure l2 encloses only that portion of the cooler which includes lthe heated air withdrawal zone 29.

'in this arrangement it is preferable that the design be such that the quantity of unheafted cooling air which enters through the openings 2l `and flows forward through the clinker inlet 'end portion of the cooler l :and then into the kiln 2 as secondary air is suliicient for good coin- Ibustion eiiiciency under :normal operating conditions. Consequently, except for variations in draft conditions which affect .-to some extent the quantity of air drawn into the cooler through the openings lll, the quantity of lair which leaves the clinker inlet end of lthe cooler :and enters the kiln las secondary `air is in most instances commensurate with eiiicient combustion requirements. However, if the draft conditions .should be such that the quantity of `secondary lair decreases, yadditional secondary :air can be introduced into .the furnace simply by regulating the valve 22 in the secondary fai-r conduit l5. All of the cool-ing air which enters the -clinker discharge end of the cooler i-s withdrawn through the openings I by ,the action of the stack structure t2 and by the operation of the blower i?, and the port-ion of this air which is withdrawn from the stack structure i2 by :the blower il is normally used only as primary lair to form a combustible mixture; i. e., the valve 22 in the secondary lair pipe t is usually maintained in its closed position. Ii necessary, however, secondary air to supplement the secondary air ysupply which enters the kiln 2 after passing through the clinker inlet portion of the cooler l may be introduced into the kiln through the pipe t simply by opening the vlalve 22 therein to the desired degree.

In this modioaton, the temperature of the air which leaves the clinker inlet end of the cooler and enters the clinker discharge or firing end of the kiln as. secondary air, is commensurate with good combustion eilciency andis materially higher than the temperature of the air leaving the clinker inlet end of the cooler in the knownY arrangements, i, e., arrangements in which all of the cooling air is discharged from the clinker inlet end of the cooler. Therefore, no fuel is wasted inlieating the secondary air to a temperature commensurate with -good combustion efficiency and since the quantity of air entering the kiln as secondary air is commensurate with good combustion efficiency under normal operating conditions, combustion eiiiciency is materially improved. The overall efficiency of the kiln is further improved due to the fact that the quantity of air passing through the kiln is always a minimum and therefore the quantity of highly heated air which is discharged from the kiln through the usual stack structure and wasted is also a minimum. Moreover, the temperature of the major por-tion of the cooling air which is withdrawn from an intermediate portion of the cooler and discharge through the stack structure i and wasted is materially less than the temperature oi the cooling air leaving the clinker inlet end of the cooler in the known arrangements and therefore the efiiciency of the disclosed clinkering and cooling arrangement is further improved in this respect; i. e., the air which is actually wasted contains less heat than the air which is wasted in the known arrangements. Consequently, with respect to known arrangements, this modification effects a greater increase in the eiiiciency of the cooler and in the overall eiiiciency of the rotary clinker cooler and kiln arrangement than does the arrangement shown in Figs. 1 5, inclusive, and is preferred for use in clinkering and cooling cement and similar materials. The particular construction and arrangement of the air withdrawal means, the air admission means and the closed clinker conveying means herein disclosed provides a durable and cheap construction which is of general application for eiecting the aforementioned im prove-d results,

The invention is obviously applicable to rotary coolers and to rotary coolers and kiln arrangem ments of general application, and it should be understood that it is not desired to limit the invention to the exact mode oi operation and to the exact details oi construction herein shown and described, as modifications within the scope of the claims may occur to persons skilled in the art.

It is claimed and desire-d to secure by Letters Patent:

l. In combination, a kiln, a rotary cooler arranged to receive and to conduct therethrough the clinker discharged from said kiln, said cooler having an intermediate portion provided with axially spaced clinker retaining rings, with one or more air passage openings in the wall of the cooler between said retaining rings, and with an enclosed clinker conveying means extending through said rings and the zone formed therebetween, means operable to introduce cooling air into a portion of said cooler remote from said openings, means including said openings operable to withdraw the air which has been introduced into said remote portion oi the cooler, and means operable to deliver Iair withdrawn through said openings into said kiln.

2. In combination, a kiln, a rotary cooler arranged to receive and to conduct therethrough the clinker discharged from said kiln, said cooler having longitudinally spaced portions into which cooling air is admitted, and an intermediate portion provided with axially spaced clinker retaining rings, with one or more air passage openings in the wall of the cooler between said retaining rings, and with an enclosed clinker conveying means extending through said rings and the zone formed therebetween, means including said openings operable to withdraw the air which has been introduced into said longitudinally spaced portions of the cooler, and means operable to deliver air withdrawn through said openings into said kiln.

3. In combination, a kiln, a rotary cooler arranged to receive and to conduct therethrough the clinker discharged from said kiln, said cooler having yan intermediate portion provided with axially spaced clinker retaining rings, with one or more air passage openings in the wall of the cooler between said retaining rings, and with an enclosed clinker conveying means extending through said rings :and the zone formed therebetween, means for introducing cooling air into said cooler adjacent the clinker inlet and discharge ends thereof, means operable to withdraw the air admitted to said cooler through said openings, and means for delivering air withdrawn from said cooler into said kiln.

Li. In combination, a kiln, a rotary cooler arranged to receive and to conduct therethrough the clinker 1discharged from said kiln, said cooler having an intermediate portion provided with axially spaced clinker retaining rings, with a partition means disposed between and in axially spaced relation with respect to said spaced retaining rings and dividing the interior of the cooler into non-communicating front and rear portions, with one or more air passage openings in the wall of the cooler between each clinker retaining ring and said partition means, and with an enclosed clinker conveying means extending through said rings and partition means and through the Zones formed therebetween, means operable to introduce air into the rear portion of said cooler at a point remote from said partition means and into the iront portion of said cooler through the opening disposed between said partition means and the clinker retaining ring disposed forwardly thereof, means including the opening in the rear portion of the cooler between said partition means and the clinker re.- taining ring ,disposed rearwardly thereof operable to withdraw the air introduced into the rear portion of-the cooler, and means operable to deliver air withdrawn through said openings into said kiln.

5. In combination, a kiln, a rotary cooler arranged to receive and to conduct therethrough the clinker discharged from said kiln, said cooler having an intermediate portion provided with axially spaced clinker retaining rings, with a partition means disposed between and` in axially spaced relation with respect to said spaced retaining rings and dividing the interior of the cooler into non-communicating front and rear portions, with one or more air passage openings in the wall of the cooler between each clinker retaining ring and said partition means, and with an enclosed clinker conveying means extending through said rings and partition means and through the zones formed therebetween, means operable to introduce air into the rear portion or said cooler at a point remote from said partition means and into the front portion of said cooler through the openings disposed between said partition means and the clinker retaining ring disposed forwardly thereof, and means including the opening in the rear portion of the cooler between said partition means and the clinker retaining ring disposed rearwardly thereof operable to withdraw the air introduced into the rear portion of the cooler.

6. In combination, a kiln, a rotary cooler arranged to receive and to conduct therethrough the clinker discharged from said kiln, said cooler having an intermediate portion provided with axially spaced clinker retaining rings, with a partition means disposed between and in axially spaced relation with resp-ect to said retaining rings and dividing the interior of the cooler into non-communicating iront and rear portions, with one or more air passage openings in the wall of the cooler between each clinker retaining ring and said partition means, and with an enclosed clinker conveying means extending through said `the clinker discharge end of the cooler and to 'rings and partition means and through the zones formed therebetween, means operable to introduce air into the cooler throughthe openings in the front portion of the cooler between said partition means and the clinker retaining ring disposed forwardly thereof and to cause the air thus admitted to flow forwardly through the front portion of the cooler and into said kiln, means operable to introduce air into azone in the rear portion of the cooler at a point remote from said partition means, and means including the opening disposed inthe rear portion of the cooler between said partition means and the clinker retaining ring disposed rearward thereof operable to withdraw the air introduced into the rear portion of the cooler.

7. In combination, a kiln, a rotary cooler arranged to receive and to conduct therethrough the clinker discharged from said kiln, said cooler having an intermediate portion provided with axially spaced clinker retaining rings, with a partition means V disposed between and in axially spaced relation with respect to said retaining rings and dividing the'interior of the cooler into noncommunicating front and rear portions, with one or more air passage openingsin the wall of the cooler between each clinker retaining ring and said partition means, and with an enclosed clinker conveying means extending through said rings and partition means and through the Zones formed therebetween, means operable to introduce air into the cooler through the opening in the front portion of the cooler between said partition means and the clinker retaining ring disposed forwardly thereof and to cause the air thus admitted to flow forwardly through the front portion of the cooler and into said kiln, means operable to introduce air into a zone in the rear portion of the cooler at a point remote from said partition means, means including the opening disposed in the rear portion of the cooler be,

tween said partition means and the clinker retaining ring disposed rearward thereof operable to withdraw the air introduced into the rear portion of the cooler, and means operable to deliver a portion of the air withdrawn through said opening into said kiln.

8. In combination, a kiln, a rotary cooler arranged to receive and to conduct therethrough the clinker discharged from said kiln, said cooler having an intermediate zone operatively connected with an air withdrawing means and means for confining and for conveying the clinker through the said intermediate Zone, means operable to introduce cooling air into the clinker inlet and discharge end portions ofthe cooler at points remote from said intermediate Zone, and

' having an intermediate portion provided with axially spaced openings in the wall thereof, with r a partition means disposed between said spaced openings and dividing the interior of the cooler l into front and rear portions each having an openycooler through the opening in said front portion and to cause air thus admitted to flow forward through the said front portion and into said kiln, and means operable to introduce cooling air into cause the air thus introduced to flow forwardly through said rear portion and out through thev opening in the forward end of the said rear portion.

10. In combination, a kiln, a rotary cooler arranged to receive and to conduct therethrough `means including a second opening in said rear portion operable to cause cooling air to now into the rear end of said rear portion, then forward toward said partition means and then out of the cooler 'through said second opening.

11. In combination, a kiln, a rotary cooler arranged to receive and to conduct therethrough the clinker discharged from said kiln, said cooler having an intermediate zone provided with an enclosed clinker conveying means extending therethrough, means including a first opening in the forward portion of said intermediate zone operable to cause cooling air to iiow into the forward portion of said zone and then forward through the cooler and into said kiln, and means including a second opening inthe rear portion of said intermediate zone operable to cause cooling air to flow into the clinker discharge end of the cooler, then forward toward the rear portion of said intermediate zone and then out of the cooler through said second opening.

12. A clinker cooler comprising a rotary shell having clinker inlet and discharge end portions and an intermediate portion provided with axially spaced clinker retaining rings, with one or more openings in the wall of the shell between said spaced clinker retaining rings, and withan enclosed clinker conveying means extending through said clinker retaining rings and the Zone formed therebetween, and means operable to cause cooling air to flow into the shell through said end portions and out through the openings in said intermediate portion.

13. A clinker cooler comprising a rotary shell having clinker inlet anddischarge end zones and an intermediate zone provided with one or more air passage openings and with an enclosed clinker conducting means extending through said intermediate zone, and means operable to cause cooling air to flow into the shell through said end zones and out through the openings in said intermediate zone.

14. A clinker cooler comprising a rotary shell having clinker inlet and discharge end portions and an intermediate portion provided with first and second air passage openings separated by a partition means dividing the interior of the shell into non-communicating front and rear portions and with an enclosed clinker conveying means extending through said partition means and beyond saidopenings, means including said first opening operable to cause cooling air to flow into the rear end of said front portion, forward therethrough and out through said inlet end, and means including said second opening operable to cause cooling air to flow into the rear end of said rear portion, then forward toward said partition means and out through said second opening.

15. A clinker cooler comprising a rotary shell having clinker inlet and discharge end openings, a partition dividing the interior of the shell' into non-communicating front and rear portions, and having an enclosed @linker conveying means extending frointhe rear end of said front portion, through said partition means and into the front end of said rear portion, means including a front opening in said shell operable to cause cooling air to flow into the rear end of said front portion, then forward toward said inlet end and then out of the shell, and means including a second openasians ing in said shell operable to cause cooling air to flow into the rear end of said rear portion, then forward toward said partition and then out of the shell.

16. A clinker cooler comprising a rotary clinker conveying shell having a partition dividing the interior of the shell into non-communicating front and rear portions, having means including openingsin said shell operable to cause a simultaneous ow of cooling air through said front and rear portions, and having an enclosed cinker conveying means extending through the said partition.

RAY C. NEWI-IOUSE.

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