US2027059A

US2027059A - Combination drier and kiln unit

Info

Publication number: US2027059A
Application number: US665284A
Authority: US
Inventors: Ray C Newhouse
Original assignee: Allis Chalmers Corp
Current assignee: Allis Chalmers Corp
Priority date: 1933-04-10
Filing date: 1933-04-10
Publication date: 1936-01-07
Anticipated expiration: 1953-01-07

Description

Jan. 7, 1936. R. c. Nx-:wHoUsE COMBINATION DRIER AND KILN UNIT Filed April 10, 1935 Patented Jan. 7, 17936 VUNITED STATES PATENT OFFICE g 2,027,059 COMBINATION ninna AND KILN Unir Application April 10, 1933, Serial No. 665,284

12 Claims.

This .invention relates in general to apparatus for drying and h eat treating materials, and more particularly to rotary kilns of the type used for drying and burning such wet raw materials as slurry used in the process of manufacturing Portland cement or the like.

To increase the effectiveness of rotary kilns in drying wet material, chains or other heat transferring elements have been arranged within kilns in such manner that when the kiln is rotated the heat transferring lements are alternately plunged into the wet material and lifted out of it covered-with a coating of the material, thereby exposing a large surface area of the material to the hot gases passing through the kiln. The heat 'transferring elements also absorb heat from the hot gases and transfer the heat to the wet material when they are again plunged intoV it.

Chains or likeheat transferring elements used in this manner have been found to be highly beneficial and to increase materially the efficiency of heat utilization of a rotary kiln. However, the chains 'installed in rotary kilns of the usual type have been limited in extent to that portion of the kiln in which the material being dried is sufliciently wet to cling to and form a coating on the surface of the chains protecting them from the destructive action of the hot kiln gases. Also, thetotal amount of chains which limited because if a large amount of chain is used at the upper or inlet end ofthe kiln the Wet material will be heated by the upper chains to such extent that itI will dry quickly on the chains at the lower end of the kiln andl will not adhere to and protect the lower chains from destruction by the hot gases.

' A general object of this invention is to provide a rotary kiln that is highly eflicient in recuperating heat from combustion gases in the process of drying wet material.

Another objectof the invention is to provide a rotary kiln of the type utilizing chains or other heat transferring elements in which more than the usual amount of heat transferring elements may be utilized economically and with 'increased eflicien'cy.

Another object of the invention is to provide a rotary kiln for drying and burning wet material in which the portion of the -kiln performing the drying operation is formed separate from the portion thereof performing the burning/operation in order that each portion may be operated lndependently in the most efli'cient manner.

Another object of the invention is to provide may be utilized in a kiln has been definitely4 meansto prevent destruction by hot kiln gases of heat transferring elements within a kiln.

Anotherobject of the invention is to provide means for introducing part of the wet material to be dried in a kiln equipped with heat transl- 5 ferring elements directly on to the heat transferring elements exposed to the incoming hot kiln gases to protect these elements from the destructive action of the hot gases.

Another object of the invention is'to provide 10 means for spraying wet material into the discharge end of the drying drum of a kiln and upon the chains therein to reduce the temperature of the incoming kiln gases and to provide a protective coating on the chains.

A further object of the invention is to provide. means for maintaining a uniform ow of wet material 'to V a kiln and to provide adjustable spraying means for spraying' a selected portion of the uniform 4iiow of material on to the chains 20 at the discharge 'end of the drying drum of the kiln.

According-to the present invention, a rotary kiln apparatus for drying and burning such material as slurry for making cement is preferably 25 divided into two independent parts, a burning drum and a drying drum, although a unitary kiln may be utilized. The drying drum is provided with chains or other heat transferring elements arranged therein for agitating and transferring heat to the slurry being dried.v Means are arranged to providea uniform flow of slurry to the kiln and means .are provided for withdrawing a regulatable portion of the material flowing to the kiln and for spraying it into the lower or discharge end of the drying drum insuch manner that it impinges upon the lower chains of the drum to form a coating protecting them from being overheated and destroyed by the incoming hot kiln gases. The spraying apparatus is so ar- 40 ranged that any. desired portion of the material supplied to the kiln may,be sprayed upon the lower chains, the remaining material being fed intothe intake end of thekilnin the usual manner. By this apparatus it possible to utilize suflicient additional chains in the kiln to reduce theD temperature of the combustion gases discharged from the kilnI to 200 F. or lower, whereas the temperature of the combustion gases discharged from kilns of usual construction is ordinarily about 400Y or 500 F,

'I'he foregoing and other objects of this invention, will be more fully apparent upon reading 'the following Dart of this specication in conjunction with the accompanying drawing and may be performed by the particularfembodiment of the invention shown by way of illustration in the several views thereof which are as follows:

Figure 1 is a view partly in side elevation and partly in longitudinal section showing a two part rotary kiln constructed in accordance with this invention Figure 2 is a View in side elevation partly broken away on the line II-II of Figure 3 showing the slurry feeder for maintaining a uniform flow of material to the kiln;

Figure 3 is a plan View of the slurry feeder shown with the top removed; and

Figure 4 is a fragmentary showing in side elevation of a unitary kiln constructed in accord-L ance with this invention.

Referring more particularly to the drawing, the two part rotary kiln shown in Fig. 1 comprises essentially a rotary drying or head drum I and-arotary burning or -tail drum 2 each so mounted as to be rotatable independently of the other. The rotary head drum I. is supported upon a floor 3 by means of spaced supporting abutments 4.which carry pairs of spaced inclined rollers 5 that engage with cooperating riding rings 6 on the outer surface .of the drum.

.Another support may suitably carry a driving pinion 8 meshing with an external gear 9 fixed on the outer surface of the drum I, and whereby the head drum may be rotated at the proper speed to advance the material to be dried therein at the proper rate depending upon the inclination at which its axis may be directed.

The rotary tail drum 2 may similarly be rotatably supported through pairs of rollers II mounted on inclined supports III carried by the floor 3, which rollers rotatably` support the drum 2 through direct bearing of external rings I2 fixed4 to the drum 2, on the pairs of rollers II. Similarly, another support may carry a driving pinion I3 which meshes with an external gear I4 fixed on the external surface of the drum 2 and which provides means for likewise rotating the tail drum 2 at the proper speed for efficient advancement of the cement materials treated therein, depending upon the particular inclination of its axis. The upper or feed end I5 of the head drum I enters a housing I6 communicating through a conduit I8 with a chimney or stack I1, a blower I9 being provided for inducing a draft through the conduit I8. A Ferris wheel feeder 20 is suitably mounted on the housing I6 and is used to measure the entire amount of Vwet material admitted to the two drums, and dispenses a portion of this material against those chains located at the lower or discharge end 22 of the head drum I and simultaneously dispenses a further portion of this material directly into the head drum I through the feed end I5 thereof. The specific features of the novel Ferris Wheel feeder 20, used with both the alternative preferred two-drum kiln and the unitary kiln, in practicing this invention, will be considered in detail in later portions of the specification.

'I'he discharge or lower end 22 of the head drum enters an intermediate housing 23 forming in effect a connecting gas passage between the tail drum 2 and the head drum I. The inlet or feed end 24 of the tail drum 2 also enters the housing 23 and the lower portion of housing 23 is shown as providing a collector pocket 26 into which is discharged the dried material leaving the head drum I, performing the drying function, the material thus being in dry condition and in proper condition for admission to the tail drum said material.

2. The dried material kcollecting inthe collector y pocket 26 is transferred to a spout 30 and admitted into the feed end 24 of the tail drum 2 by means of an elevator 21 having elevating mechanism 28 including buckets 1 andr driving 5 gear and pinion 29. The lower or discharge end 25 of the tail drum 2 enters a firing hood 32 which provides a passage to a discharge bin 3| provided in the floor 3, for materials completely treated in the kiln.

A fuel injection device 33 has a nozzle 2| enter` ing the ring hood 32 and directed in approximate alinement with the axis of the tail drum 2, said `fuel injection device forming the means for burningfuel in the tail drum 2 resulting in the 15 hot combustion gases which move along the interior of the kiln or heating chamber in a direction opposite to that of the advance of thematerial therethrough and in direct contact with The hea`d drum I is provided with transverse, fiexible heat transferring members of metal as, for example, chains 34 which serve to provide the desired increased amount of heat absorbing surfaces for the adherence and heating of the wet 25 raw material to be directly exposed to the hot gases of combustion coming from the tail drum 2. The chains 34 immediately adjacent the point vof connection of the lhousing 23 and the head drum I are protected 'through spraying 30 `upon them a portion of the wet raw material,

in the form of slurry, as indicated, in the manner nowto be explained. l

'I'he Ferris wheel feeder 20 comprises a main receptacle 35 having a side wall a portion of 35 which forms also one wall of an auxiliary receptacle or supply sump 40. The supply sump 4II is in communication through an aperture 4I located in said common side wall with a hopper 42 disposed within the main receptacle 35 and carried 40 by the said common wall of the receptacles. 'I'his hopper 42 receives the wet raw material permitted to fall by gravity from the buckets 31 of the Ferris wheel 36, which is suitably carried by the other side wall of the main receptacle, as illus- 45 trated, and is rotated at the proper speed.v

The wet raw cement material or slurry, preferably of the highest workable consistency to keep as low as possible the amount of' heat to be exl pended in evaporating its water content while 50 within the drum I, is admitted into the main receptacle 35 through an inlet pipe 38. The elevation of the raw cement materials in the main receptacle 35 is primarily controlled by an outlet or overflow pipe 39 connecting into the interior 55 of the main receptacle, at the desired elevation. The sump 4U has a standpipe 43 therein, one branch 45 of which terminates in an end having a removable closure 46 provided for the insertion of proper tools to clear the passage from the (i0 standpipe 43 to its main branch 44, shouldl this passage become clogged. The main branch 44 serves as an inlet spout for the major portion of slurry admitted directly into the feed end I 5 of the head drum I in directionfcounter to the 65 flow of hot gas therethrough. The sump 40 further has a pipe 48 communicating with the interior thereof adjacent its bottom, which pipe aoaaoso of housing 23, and into the lower end of the head drum I in the same direction as the gas flow, so that the spray rst negotiates the gases traveling through the housing 23 and subsequently directly engages` those chains located nearest the discharge end of the head drum, for the purpose of coating these chains with the proper amount of wet slurry, particularly on the sides thereof first engaged by the hot gases, to prevent their rapid deterioration by the hot combustin gases leaving the housing 23, to which these chains are continuously subjected.

The function of the Ferris wheel feeder 20, is to handle all .the slurry which is ultimately introduced at the vdescribed places into the head drum and thereby supply the entire feed to the kiln at a uniform rate of iiow with constant* rotation of the Ferris wheel 36. The purpose of the hopper'42 is to receive the uniform flow of material, determined by the number of buckets on the Ferris wheel 36 and by the number of revolutions of the Ferris wheel 36, and

to feed the material uniformly through the opening 4I to the common sump 40. The arrangement in the sump 40 is such that with a certain head provided and maintained by the Ferris'.

wheel 36, the pump 41 will be able to supply a uniform portion of the slurry through the nozzle 50 onto the chains 34 at the lower end of the head drum I. The corresponding head on the standpipe 43 will effect the introduction of thel remaining portion of the slurry directly into the feed end I5 of the head drum I.", The effect -of the tempered gases upon the chains above these lower chains in the head drum I and beyond the range of the spray from nozzle 5l), is of little importance since the portion of the slurry admitted directly into the feed end I5 through the standpipe 43, will permit these chains to engage and intermingle with advancing wet slurry to keep them at the proper temperature. These actions simultaneously effect almost a complete drying of the advancing material as the range of the spray from nozzle 50 is approached. The action of the drying zone is such that the slurry will be in substantially dry condition as it leaves the head drum I, as above described.

Figure 4 illustrates the alternative application of the invention in a unitary kiln IOI having the defined burning and drying zones. The drying zone of the unitary kiln IUI illustrated fragmentarily in this figure is similarly provided with the chains 34 or other metallic heat transferring 'members for increasing the heating surface for this zone may also be provided with the rings 6 and with the ring gear9 contributing in the support and rotation respectively, of the unitary kiln. A portion of the slurry or other wet raw material may be dispensed into the feed end of the kiln IIJI, by means of the inlet' spout 44 of the Ferris Wheel feeder illustrated in Figs. l, 2 and 3 and described in connection with these figures.

In order to supply the desired portion of the wet raw material to the chains at the lower end of the drying zone, the pipe 49 connected to the discharge of the pump 41 of Fig. 1 is connected with a nozzle 50| through the intermediary of a further pipe 49 `provided with connections about to be described. For this purpose a pipe 6I may be extended through the wall of kiln I-IJI adjacent its feed end, which pipe 6I may be secured to said wall by means of a iianged member62. An axially positioned union 60 allows proper rotative movement of the pipe 6I with respect to an end of the described interrupted pipe 49. Beyond the interrupted pipe 49 the further pipe 49 is secured to the kiln IUI, and 5 one of the ends of this further pipe 49 is connected by means ofa union 63 with the outwardly projecting end of pipe 6I. The other end of the further pipe 49 is connected to the outward- 1y projecting end of the nozzle 50 I held by means 10 of another flanged member 62 fixedly with respect tothe kiln IIJI, by means of another union 63. The arrangement of the invention in the unitary kiln of Fig. 4 and the manner-in which the invention is practised therein should be clear l5 when the arrangement is referred to Fig. 1 and to the detailed description of the operation of the kiln shown in this figure.

It should-be understood that it is not intended to limit the invention to the constructions shown 20 and described for various modifications within they scope of the claims may occur" to persons skilled in the art.

It is claimed and desired to secure by Letters Patent:

l. A heater of the direct contact hot gas now type comprising means therein adjacent the material inlet end of said heater for increasing the surface area of contact for the material, means vfor introducing counter to the gas flow a portion of the material to be heated,'and means for introducing in the same direction as the gas ow another portion of the material to be heated.

2. A heater of the direct contact hot gas flow type comprising means therein adjacent the material inlet end of said heater for increasing the surface area of contact for the material, means for producing a ow past said area increasing means of a major portion of the material to be heated counter to the gas iiow, and 40 means for producing a ow past said areal increasing means in the same direction as the gas flow of a minor portion of the material to be treated.

3. In a rotary kiln having metallic members near its feed end and extending across the inner surface at said feed end, a supply for furnishing wet material to said kiln, an adjustable feeder device for feeding said supply with regulatable quantities of said Wet material, means for feeding a portion of said wet material to the feed end of the kiln and means for introducing a further portion of said wet material directly on to those metallic members nearest the discharge end of the kiln, each of said means including a supply conduit and said conduit originating at different head levels from said supply.

4. In a rotary kiln having metallic members near its feed end and extending across the inner surface thereat, means for supplying wet material to the feed end of the kiln, and means for `the introduction of a further portion of said wet material at a point adjacent those metallic members nearest the discharge end of the kiln, both -of said means connecting into a common sump and including conduits terminating at different head levels therein, said sump being supplied with regulatable quantities of said material by an adjustable feeder device, one of said means further including a forcing means the operation of which together with a given ldelivery of the feeder device determining the proportion of said material admitted to the kiln at the described points.

5. A rotary kiln for the burning and drying of 76 raw cement material introduced as slurry, comprising a rotary head drum, means for rotating said drum, a rotary tail drum, means for separately rotating said tail drum, means for introducing heat into said tail drum, means for introducing slurry into said head drum at the inlet end thereof, the drums being arranged and the arrangement cooperating with means communieating with said drums whereby the advance of the material being treated in the drums is in a direction opposite from the travel of the hot gases through the drums, and slurry conveying means connecting a portion of the means communicating with the drums and the means for introducing slurry into the head drum, for introducing a further portion of slurry into said head drum at the other end thereof, to provide an increased heat recuperation within the kiln.

6. A rotary kiln for the burning and drying of raw cement material introduced as slurry, comprising a rotary head drum, means for rotating said drum, flexible heat conducting members extending along and located transversely within said head drum, a rotary tail drum, means for separately rotating said tail drum, means for introducing heat into said tail drum, means for introducing slurry into said head drum a"t the inlet end thereof, the drums being arranged and the arrangement cooperating with means communicating with said drums whereby the advance of the materials being treated in the drums is in a direction opposite from the travel of the hot gases through the drums, and siun'y conveying means'connecting a portion of the means communicating with the drums and the means for introducing slurry into the head drum, for introducing a further portion' of slurry into said head drum and against the members at the other end thereof, to provide an increased heat recuperation within the kiln.

1. A rotary kiln for the burning and drying of raw cement material introduced as slurry,4 comprising a rotary head drum, exible heat conducting members extending along and located transversely within said head drum, means for rotating said drum, a rotary tail drum, means for separately rotating said tail drum, means for introducing heat into said tail drum at the discharge end thereof, means for introducing regulatable portions of slurry into the head drum at the inlet and discharge ends thereof, means communicating with the drums and forming a connecting passage for the travel of gases through the drums in a direction opposite from the passage of the material being treated therethrough, and means for conveying material discharged from the head drum, to the tail drum. Y

8. A rotary kiln for the burning and drying of raw cement material introduced as slurry, comprising a rotary head drum, flexible heat conducting members extending along and located transversely within said head drum. means for rotating said drum,` a rotary tail drum, means for separately rotating said tail drum, means for introducing heat into said tail drum at the discharge end thereof, means for introducing regulatable portions of slurry into the head drum at the feed and discharge ends thereof, means communicating with the drums and forming a connecting passage for the travel of the gases through the drums in a direction opposite from the po of the material being treated through the drums, means for conveying material discharged from the head'drum to the tail drum, the means for introducing slurry at the discharge end of the head drum including a nozzle effecting a spraying of wet material within said passage thus subjecting the moving gases thereat to temperature reductions and a spraying into the head drum and onto the flexible members therein located 5 and extended thereaiong by reason of their being within the range of cooling and coating influence of the slurry spray projected from said nozzle.

9. In combination, a pair of segregated, rotary drums for heat treating of wet material passed progressively and successively through the rotary drums, means providing heat liberating gases passing through the drums in a direction opposite from that of the material, means for regulating the entire feed to the drums, said means comprising a bucket wheel submerged in a container having provision for maintaining a substantially constant head of wet material therein, the buckets of said wheel emptying into a container provided with a ow passage to a sump, and separate conduits communicating at different points with said sump and directed into the ends of one of said drums.

10. In combination, a pair of segregated, rotary drums for drying and burning of wet cement raw material passed progressively and successively through the drums, means providing heat liberating gases passing through the drums in a direction opposite from that of the material, one of said drums being provided with heat conducting flexible members extending along and located transversely of the inner surface thereof and located intermediate the two ends thereof, means for regulating the entire feed to the drums, said means comprising a Ferris wheel feeder having a delivery sump and separate conduits communicang with the sump at different head levels and delivering to the ends oi.' the said drum provided with the flexible members, a pump being provided in the conduit leading to the discharge end 40 of the drum provided with the flexible members to provide a positive flowy of material through its conduit, the other conduit removing the excess material over that necessary to be supplied to the discharge end of the drum provided with the fiexible members, to carry out the temperature reductions of the gases and coating of the flexible members. for heat protection purposes as described, to the feed end of said drum provided with the exible members.

11. A direct contact heater, comprising a chamber, means for owing hot `gas through said chamber, heat absorbing elements disposed within said chamber, means for flowing material to be heated through said chamber in contact with said heat absorbing elements, and `means for pro- Jecting a portion of the material to be heated directly upon the heat absorbing elements first contacted by the intlowing hot gas in direction to impinge upon the sides of said elements irst en- 00 gaged by said gas to protect said elements from destruction by said hot gas.

12. A rotary kiln, comprising a rotatable casing, heat transferring means disposed within said casing, means for owing hot gases through said casing, means for flowing wet material to be heated through said casing in direction counter to the gas flow, and means for spraying a portion of said wet material to be heated in the direction of said gas flow on to the heat transferring means first contacted by the incoming hot gases to protect said means from being destroyed by said hot gases.

RAY C. NEWHOUBE. 7l

, CERTIFICATE o F CORRECTION.

'Patent No. 2,027,059. January 7, 1936.

` RAY o. NEwHoUs-E.

" 4It is hereby certified that error appears in the printed specification of the above Anumbered patent requiring correction as follows: Page E, secorlld column, line 56, p claim 3, for "conduit" read conduits; page 4, second column,

line 35, claim 10, for "Ferris" readwferris' and that the said Letters Patent should be read. with these oorrectiors 'therein that the same may conform to the record of the case in the Patent Office.

Signed. and sealed this 11th day of February, A.' D. 1936.

,Leslie Frazer (Seal) Acting Commissioner of Patents.