US2348446A - Rotary cooler - Google Patents

Description

Patented May 9, 1944 UNITED STATES PATENT OFFICE ROTARY COOLER George D. Becker, Wauwatosa, Wis., assignor to Allis-Chalmers Manufacturing Company, Milwaukee, Wis., a corporation of Delaware Application August 9, 1943, Serial No. 497,916

12 Claims. (Cl. 263-44) This invention relates to conveyors and indi rect coolers for hot materials and their combination with furnaces discharging hot materials.

It is well known in the art to indirectly cool hot materials issuing from a furnace by feeding them into a header from which they are conveyed through material cooling tubes passing through a cooling space within a drum-like conduit. It is also well known to divide the cooling space into two or more stages and to conduct heated cooling medium from one or `more of said stages to said furnace to support combustion, the cooler being arranged to keep dust from the material being cooled from mingling with the cooling medium. It is also well known to conduct cooling medium within the drum but out of contact with the cooling tubes lto a highly heated point in said cooling space near the header and feed ends of the tubes.

This invention concerns an improved cooler in which the feed header is provided with a double tube sheet wall, that is, a shallow space is walled off from the cooling space proper adjacent the feed header plate, and a stream of cooling air is supplied to said space independently of the air supply to the cooling space proper, to cool the tube sheet or header plate and tube ends where they are in contact with hot material in the header, and provide a fluid current to carry away materials which might tend to leak from the feed header and for cooling medium which might leak from the cooling space proper into the header. This invention thus improves cooling of the header plate'or tube sheet and tube ends and also aids in preventing dust from entering the furnace either through the hot material conduit carried by cooling air leaking into the header, or through the combustion air supply proper carried by the main stream of cooling air.

An object of this invention is to secure improved cooling of a cooler header plate.

A further object is to secure improved safeguard against carrying of dust from the cooler into a calcining furnace.

Other and further objects will appear in the following description with reference to the accompanying drawing in which:

Fig. l is `a fragmentary vertical longitudinal sectional view of a cooler and furnace embodying the invention;

Fig. 2 is a fragmentary view to an enlarged scale of the feed header end of the cooler of Fig. l;

Fig. 3 is a cross section taken on the line III- III of Fig. 2; and

Fig. 4 is a view similar to Fig. 2 of a modified cooler feed header structure. 1

Similar reference characters refer to similar parts throughout the several figures of the drawing.

In Figs. l, 2 and 3 of the drawing is shown the discharge and firing end of a kiln or calcining furnace I having a hot material discharge opening 2 and a combustion air inlet 3. A cooler 4 is rotatably supported on bearings 5. A feed conduit 6 is arranged to conduct hot material discharged from furnace I into a feed header section I0 atl one end of the cooler drum or shell 9. Feed header III is :provided with a refractory lining I I. The feed header I0 may be considered as including as an outer wall, a portion of the drum or shell 9. The feed header plate I2 and the division plate I3 maybe considered as spaced tube sheet walls separating the interior of header I0 from the interior of the drum 9 to the right of division plate or tube sheet wall I3, and enclosing a shallow space between them. Openings I4 are provided in the section of the drum shell 9 forming the outer wall of Vthe feed header III. These openings I4 communicate with the shallow space between spaced tubesheet walls I2 and I3 for a purpose to -be described hereinafter.

Muie tubes or `irnperforate hot material conveying and cooling tubes I6 have their ends supported ,in spaced relation in said tube sheet walls I2 and I3. These muflle tubes extend through spaced tube sheet walls I2 and I3` and open into the interior or material-receiving space of header I. The portion ofthe cooler to the right of tube sheet wall` or division plate I3 is briey described hereinafter, and more fully described in A. J. Roubal United States Patent No. 2,283,129, dated May l2, 1942, in connection with a similar structure.

Muilie tubes I6 extend longitudinally through drum 9 in a concentric row and pass in sealed relation through the header plate I1 opening into discharge header or hood structure I8. Mule tubes I6 also are supported by and eX- tend through a division plate or partition I9. A central air tube 20 having a closed end 2l extends through division plate I9 and is supported within the drum as described in said Roubal Patent 2,283,129, but with its closed end 2| spaced from tube sheet I3. Air 0r other cooling fluid is conducted to air tube 20 through conduit 22 and to the space surrounding air tube 2| through conduit 23 extending through discharge header or hood I8 and header plate II as in Roubal Patent 2,283,129. Apertures 24 are provided in air tube III As shown in Figs. 1 and 2 the feed header plate or tube sheet wall I2 may be provided with an annular flange 3| and mountedin relatively slidable sealing relation with the inner surface of header section I of drum shell 9.

The interior of the drum 9'to the right of feed header division plate I3 is seen to be divided into a precooling chamber 36 extending to division plate I9 and a nal cooling chamber 31 extending to discharge header plate I1.

A modied form of header is shown in Fig. 4. In this form, an inner cylindrical header wall 32 is radially spaced inwardly from outer wall 9.

The feed header takes the form of an inner tube sheet wall I I2 circumferentially attached to inner header wall 32. 'I'he tube sheet wall or division plate I3 is spaced from the header or tube sheet wall II2 and attached circumferentially to the drum shell 9. The space between walls I I2 and I3 is now seen to be extended to include the annular space between drum shell 9 and inner header wall 32. Apertures II4 are header section I0 of drum shell 9.

A blower 33 driven by a motor 35 may be prcvided and may be connected to a semiannular air chestv 34' partially surrounding header I0 and communicating with apertures I4, or I I3. The blower arrangement is shown in Figs. l, 2 and 3 but may be modified in an obvious manner to be applied to the modified header of Fig. 4.

The operation of the device as to the portion to the right of the tube'sheet or division plate I3 is similar to'that of the device disclosed in the Roubal Patent 2,283,129. Combusion air for furnace I enters air tube 2I and flows through aperures by suitable baiiles, and passes out apertures 26 through housing 8 and conduit 'I to furnace air inlet 3. This air is highly heated by the time it reaches the vicinity of tube sheet Vwall I3 and apertures 25. Final cooling air enters through conduit 23V and flows around air tube 2l and around the mule tubes I6 guided by suitable baffles and is exhausted through apertures 21 to a stack or other means. not shown, connected to collector 29. Cooling of the header plate or tube sheet wall I2, and the extreme ends of muiile tubes I6 which are in direct contact with the hot material from the furnace and improved cooling of tube sheet wall or division plate I3 at the hottest part of the material cooling space proper are specially provided for byvthis invention. The shallow space between the tube sheet walls I2 and I3 (and the space in Fig. 4 surrounding inner 'header wall 32 and extending between tube sheet walls II2 and I3), forms a special separate space for independent cooling of the hottest header parts. Air ilowV through apertures i# (I I4) will be induced by gravity due to the hot parts bordering the enclosed shallow space and this air is fresh cool air which has not passed through the cooler body prior to its entry through openings I4 (I I4),

provided in 24 around the muille tubes I6, being guided If gravity flow is insufcient, a blower 33 may be used to augment flow.

The flow of air between walls I2 and I3 (I I2 and I3) and discharged to atmosphere has a sealing function in addition to its cooling function. Joints where the tubes I6 are passed through tube sheet walls I 2 and I3 and joints between these walls I2 and I3 and the drum shell 9 (and inner wall 32 in Fig. 4) are diicult to keep tight. In a single walled structure like that of Roubal 12,283,129, dust from the interior of the material receiving chamber (26 in the Roubal patent) l which might leak through the header plate (l1 in the Roubal patent) will be carried by the flow of cooling and combustion-supporting medium into the furnace I. Also cooling and combustionsupporting medium which might, in such a structure, leak past the header plate (11 in Roubal) will stir up and carry dust from the material receiving chamber (26) to the furnace (I) through the furnace discharge (3). In the device of this invention any leakage of dust from feed header I0 through tube sheet Wall I2 will be discharged through apertures I4 without entering the furnace I. Also any leakage of cooling medium through tube sheet Wall I3 will be discharged through apertures III without entering the material receiving space in the header.

Undue strain on the tube sheet wall I2 due to expansion and contraction of the ends of tubes I6 is avoided by use of a slidable joint with the drum shell as shown at 3 I.

The invention is of general application and although it has been disclosed in connection with a muille tube cooler of the type shown in Roubal 2,283,129,it should be understood that it is not intended to limit the invention to the exact details of construction and mode of operation herein shown and described. Such modifications and equivalents `as may readily occur topersons skilled in the art are intended to be included' within the scope of the invention as defined by the appended claims.

It is claimed and desired to secure by Letters Patent:

1. A cooler for indirect cooling of hot materials comprising a substantially horizontal elongated rotary drum, a feed header plate closing said drum adjacent one end, a discharge header plate closing said drum adjacent the other end, a plurality of spaced imperforate material conveying and cooling tubes extending between and connecting said header plates, a division plate in said drum adjacent said feed header plate and transversely enclosing a shallow space adjacent said feed header plate and surrounding the walls of said tubes adjacent their feed ends, means effecting flow of a stream of cooling air in the interior of said drum between said discharge header plate and said division plate, and means effecting flow of a separate stream of cooling air through said shallow enclosed space adjacent said feed header plate, said streams of cooling air being in non-mixing relation andfree of contact with heated material in said cooler.

2. A cooler for indirect cooling of hot materials` comprising a substantially horizontal elongated rotary drum,' a feed header plate closing said drum adjacent one end, a discharge header plate closing said drum adjacent the other end, a plurality of spaced imperforate material conveying and cooling tubes extending between and connect ing said header plates, a division plate in said drum adjacent said feed header plate and transversely enclosing a shallow space adjacent said feed header 'plate and surrounding the wallsof saidtubes adjacent their feed ends, means effecting flow of a stream of cooling air in the interior of said drum between said discharge header plate and said division plate, and -a plurality of peripheral apertures in said drum between said division plate and said feed header for effecting flow of a separate stream of cooling air through said shallow enclosed space adjacent said feed header plate in non-mixing relation to 'saidrst stream and free of contact with heated material in said cooler.

3. The cooler of claim 2, said drum `having its feed header plate axially slidable in sealing relation with the inner surface of said drum, and said division plate being rigidly secured in sealing relation with said drum and the outer walls of said tubes.

4. A cooler for granular materials comprising chamber and through said division plate into said precooling chamber, at least one imperforate muflle tube connecting said headers and extending through said precooling and final cooling chambers, means including said central air tube for effecting a flow of separate streams of cooling air through said precooling and final cooling chambers, and means for effecting flow of still another separate stream of cooling air through said shallow space between said spaced tube sheet walls.

5. In combination with a furnace, means for conveying and cooling the hot material discharged from said furnace, comprising an elongated drum, a feed header enclosing one end of said drum for receiving and transmitting said hot material, a discharge header enclosing the other end of said drum, a plurality of spaced material conveying tubes connecting said headers and eX- tending longitudinally therebetween through the said drum, means for effecting a flow of combustion-supporting cooling medium through the interior of said drum between said headers and externally of said tubes, fluid conduit means for conducting at least a part of the combustion-supporting cooling medium from the interior of said drum to said furnace to support combustion therein; said feed header having spaced parallel tube sheet walls enclosing a fluid cooling space surrounding the said tube walls adjacent their ends, and means to effect a flow of cooling fluid through said space between said tube sheet walls entirely independent of the flow of cooling medium through the interior of said drum and furnace.

6. In combination with a furnace, means for conveying and cooling the hot material discharged from said furnace, comprising an elongated drum, a feed header enclosing one end of said drum for receiving and transmitting said hot material, a discharge header enclosing the other end of said drum, a plurality of spaced material conveying tubes connecting said headers and extending longitudinally therebetween through the said drum, means for effecting a flow of combustion-supporting cooling medium through the in terior of said drum between said headers and externally of said tubes, fluid conduit means for conducting at least a part of the combustionsupporting'cooling medium from the interior of saiddrum to said furnace to support Combustion therein; said feed header having spaced parallel tube sheet walls enclosing a fluid cooling space surrounding the said tube walls adjacent their ends, and means to effect a flow of cooling fluid through said space between said tube sheet walls entirely independent of the flow of cooling medium through the interior of said drum and furnace, said tube sheet wall facing the interior of said drum being rigidly attached to the periphery of said drum, and said other tube sheet wall facing the header chamber engaging the inner surface of said drum in slidable sealing relation.

'7. A `header for a plurality of hot material conveying tubes comprising a drum-like box, closely spaced parallel tube sheet walls Asurrounding `the walls of said tubes adjacent one end thereof and enclosing a shallow space therebetween, and means effecting a flow of cooling fluid directly to, transversely through, and from, said shallow space between said spaced parallel tube sheet walls in non-contacting relation to said hot material.

8. In a cooler for hot materials, a rotating drum with its axis slightly inclined to the horizontal, a feed end sealing header plate closing said drum at the higher end thereof, a plurality of spaced imperforate material conveying tubes opening through said feed end header plate and extending longitudinally of said drum toward the lower end thereof, a discharge header plate closing the drum at the discharge end thereof between said tubes, means to effect a flow of cooling air through a portion of the enclosed space within said drum between said hot material conveying tubes throughout a major portion of the length thereof, means transversely dividing said enclosed space immediately adjacent said feed end header plate, and means to effect a flow of cooling air through the space VIbetween said feed end sealing header and said division means free of contact with said hot material and in independent non-mixing relation to said first mentioned flow of cooling air.

9. A cooler for indirect cooling of hot materials, comprising a substantially horizontal elongated rotary drum, a feed header closing said drum adjacent one end, a discharge header closing said drum adjacent the other end, a plurality of spaced imperforate material conveying and cooling tubes extending between and connecting said headers, a division plate in said drum adjacent said feed header and transversely enclosing a shallow space adjacent said header and surrounding the walls of said tubes adjacent their ends, said drum being constructed and arranged to provide an annular cooling space surrounding said header and freely communicating with said shallow space adjacent said header, means effecting ow of a stream of cooling medium in the interior of said drum between said discharge header and said division plate, and means effecting flow of a separate stream of cooling fluid through said shallow enclosed space and said annular cooling space, said streams of cooling fluid being in non-mixing relation and free of contact with heated material in said cooler.

10. A cooler for indirect cooling of hot materials, comprising a substantially horizontal elongated rotary drum, a feed header closing said drum adjacent one end, a discharge header closing said drum adjacent the other end, a plurality of spaced imperforate material conveying and cooling tubes extending between and connecting said headers, a division plate in said drum adjacent said feed header and transversely enclos-- ing a shallow space adjacent said'header and surrounding the walls of said tubes adjacent their ends, said drum being constructed and arranged to provide an annular cooling space surrounding said header and freely communicating with said shallow space adjacent said header, means effecting flow of a stream Vof cooling medium in the interior of said drum between said discharge header and said division plate, and a plurality of peripheral apertures in said drum communicating with said shallow enclosed space adjacent said feed header and said annular space surrounding said feed header for effecting flow of a separate stream of cooling uid therethrough in non-mixing relation to said first mentioned.v

stream and free of contact with the heated material in said cooler.

11.'A header for a' plurality of hot material conveying tubes comprising a drum like box havingv radially spaced inner and outer walls, spaced parallel tube sheet walls surrounding the walls of said tubes adjacent their ends, and connected respectively to said radially spaced inner and outer walls to define a cooling space, and means effecting a ow of cooling fluid through said cooling space.

12. A header for a plurality of hot material conveying tubes comprising a drum like box having radially spaced inner and outer walls, spaced parallel tube sheet walls surrounding the walls of said tubes adjacent their ends, and connected respectively to said radially spaced inner and g outer walls to define a cooling space, and aper-

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