US1959061A - Drier - Google Patents

Description

May 15, 1934.

P. R. PERKINS DRIER Filed June 16, 1955 'n'bRNEv Patented May 15, 1934 UNITED STATES PATENT! OFEICE Claims.

This invention relates to driers and relates particularly to driers designed and adapted for drying materials having a high moisture content, of the general type which forms the subject- 5 matter of U. S. Letters Patent No. 1,098,402, dated June 2, 1914.

Stated generally, a principal object of the invention is to provide a drier of the general type specified adapted for effectively and economically drying sewage sludge and similar materials, which tend to form into balls as the material is fed through the drier shell-which frequently are of considerable size and to the interior of which the heat penetrates very slowly, thus delaying the l drying operation and increasing the cost thereof.

Specifically, an important object of the invention is to provide a drier construction whereby, in operation, the material being treated will be subjected to a more effective cascading or tumbling action during its passage through the drier, than occurs in any present drier of this type of which I have any knowledge, which will operate to break up balls which may form therein, in opera! tion, into relatively small parts or fragments,

which will permit the heat to act thereon more directly and effectively than heretofore, correspondingly reducing the time and expense of drying said material.

A further object of the invention is to effect a more uniform distribution of the hot gaseous fluids or products of combustion throughout the portion of the drier shell traversed thereby, and a more intimate contact thereof with the materialbeing treated, thereby further reducing the time required for and the expense of drying the material.

Still a further object of the invention is to provide a construction and arrangement, whereby material delivered into the drier shell-having a maximum moisture content-will be exposed both to the direct action of the hot gaseous fluids and products of combustion from the furnace, and

also to radiant heat emanating from the heated' shell and associated parts of the drier; while adjacent the discharge end of the drier the partly dried or dehydrated material, normally will be subjected to radiant heat only, thus insuring against overheating of the material and the possibility of ignition and combustion thereof;a but of, a drier embodying my invention and improvements comprises the various features, combinations of features and details of construction hereinafter described and claimed.

In the accompanying drawing in which the invention is fully illustrated, Fig. 1 is a central, longitudinal, vertical sectional side view of a drier embodying my invention and improvements; and r Figs. 2 and 3 are, respectively, enlarged sec- 6 tional elevations of the drier shell on the lines 22 and 33 of Fig. 1.

Describing the invention with reference to the drawing, the drier, designated as a whole A, comprises a cylindrical shell 1 rotatably mounted at l an angle to the horizontal, with its feed end somewhat higher than its discharge end, in a usual manner. As shown, the drier shell is rotatably mounted by usual tire bearings designated as a whole a, a, 76

and, in operation, rotation is imparted to said shell by means of a gear and pinion drive desig- 'nated as a whole b, the pinion of which, as shown,

is secured directly to the shaft of an electric motor designated as a whole 0.

As shown, also, the front end of the drier shell 1 is closed by a vapor bonnet 2 the interior of which is connected by a pipe or conduit 3 with the eye of a fan exhauster d and the rear end of said shell extending intoa fixed hood designated as a whole e provided in its lower end with a discharge opening 4.

Material to be dried is adapted to be delivered into the shell 1 of the drier'A by means of a screw conveyor designated as a whole 1 operatively supported on the vapor bonnet 2, said screw conveyor being provided at its front end with a hopper 5 and its rear end extending through the vapor bonnet and discharging into the feed and of the drier shell, as shown.

As shown, also, a section of the drier shell 1 adjacent its feed end is enclosed by a furnace setting designated as a whole B, provided in its end walls with holes or openings through which the drier shell extends, and which comprises a fire-box designated as a whole G, and a chamber for the hot gaseous fluids and products of combustion, which is divided by a transverse arch into a lower compartment '9 which communicates directly with the fire-box an'lan upper compartment 9 in which the drier shell 1 is exposed directly. As shown, also, the furnace arch comprises a front imperforate section 7 and a rear section 8 provided with holes or openings 9 through which the hot gaseous fluids and products of combustion pass 119 from the lower chamber g to the chamber 9' in which the furnace shell is exposed, the holes 9 in the section 8 of said arch preferably being than would occur if said holes'were all of the same size.

In accordance with present common practice, also, a cascading or tumbling movement is imparted to the material as it is fed through the drier shell 1, by flights 10 secured to the inner surface of said drier shell, said flights comprising impeller flights 10' at the extreme front end of the drier shell, to which the material to be dried will be delivered by the screw conveyor 1, and which will deliver said material to the first flights 10 and'prevent it from entering and possibly obstructing the vapor bonnet 2;

Driers embodying all of the foregoing features and details of construction are old and well known to persons familiar with such structures and can be readily supplied without the exercise of invention.

In accordance with the present invention, my improved drier comprises a plurality of flues 11, of relatively small diameter, supported within and which extend lengthwise of the drier shell 1, the front ends of said flues being closed and terminating at a distance from the front end of said drier shell, and their rear ends, as shown, being connected to and being in open communication with a header 12, supported in said drier shell at a short distance from its rear end.

As shown, the front ends of the flues 11 are supported by and in open communication with the compartment 9' of the furnace setting B-in which the drier shell 1 is exposed, as heretofore explainedby means of open-ended pipe sections 13, opposite ends of which are secured in holes formed in the drier shell 1 and in the flues 11, respectively.

As shown, the header 12 is supported on the drier shell 1 by brackets 14, and, for reasons presently explained, comprises a relatively small, tubular extension 12', supported directly by brackets 15. The rear end of said extension 12' is open and is controlled by a damper 16 secured to a rod 1'1 slidable endwise in bearings formed in a spider 18 secured in the header extension 12' and in the rear wall of the discharge hood e. As shown, a flange 19 is formed at the rear end of the header extension 12', said flange comprising an inner, plane section 20, which forms a seat for the damper l6 and an outer rearwardly flared section 21, to prevent fed material from entering said housing. As shown, the damper 16 is controlled to open and close the same by a pivoted handle 17' to which the rod 17, to which the damper 16 is secured, is connected.

The flues 11 are provided with ports 22, through which, in operation, hot gaseous fluids and products of combustion pass from said flues into the drier shell 1, a circulation of hot gaseous fluids and. products being maintained, in operation, from the furnace G through the compartments g, g, the pipe sections 13, the flues l1, and the ports 22, into the interior of the drier shell and frontwards in said shell, into and through the vapor bonnet 2 and pipe or conduit 3 to the fan exhauster d and thence to atmosphere or elsewhere, To prevent fed material from falling into the flues 11 through the ports 22, flared guards 23 of suitable sheet metal are secured to said flues in position to extend over said ports, as shown. In the preferable construction shown, the ports 22 are arranged ingroups, each flue being provided with a plurality of such ports spaced lengthwise thereof and the ports or groups of ports of adjacent flues being staggered or arranged out of line with each other transversely.

In what I now consider preferable construction, the drier comprises four flues 11 arranged symmetrically with reference to the axis of the drier shell, the diameter of said flues, respectively, being approximately one-eighth A) the diameter of the drier shell 1, and being arranged with their centers in -a circle described from the center of the drier shell, on a radius approximately equal to one-half the length of the radius of said drier shell. I do not, however, desire to limit myself to the exact dimensions or relation described, as these admit of a wide range of variation within the scope and contemplation of the invention, as definedin the appended claims.

As shown, the flights 10 may be described as scoop-shaped, their outer edges being angularly inclined relative to their attached portions in the direction of rotation of the drier shell, the relation being such that material elevated thereby will all be discharged therefrom as the advancing edges of said flights, respectively, approach a vertical plane through the center of the drier shell, when passing through an are at the top of said drier shell, and attain a position in which material falling therefrom by gravity, will impinge upon a flue 11 approaching a vertical plane through the center of the drier shell, at the lower side of said drier shell, which, with a drier shell having a diameter of approximately 8 feet or more, will produce an impact sufficient to break up any balls which may be formed as the material is fed through the drier shell, thus affording effective access of heat to all parts of the material.

With a drier having the construction described, it is obvious that material traversing, the shell from its feed end to a point therein in line with the ream-most port or group of ports 22 in any of the flues 11 will be subjected to the direct action: first, of the hot gaseous fluids and products of combustion traversing the drier shell from said ports or groups of ports to the vapor bonnet; and second, to radiant heat emanating from the drier shell 1 and from the flues 11, whereby material delivered into the drier shell and having the maximum moisture content will be subjected to maximum temperatures;

That, due to the use of a plurality of relatively small flues 11 with the ports 22 arranged as described, the heat will be very evenly distributed in all parts of the drier shell, and all material therein will be subjected to substantially the same treatment;

It is also obvious that rearward from the last port or group of ports 22where the moisture content of the material is relatively much smaller than when delivered into the drier shell, the material will be subjected to the action of radiant heat emanating from the drier shell 1, the "dead ends of the flues 11 adjacent the header 12, and. said header, including the extension 12' thereof--excepting when it is found that the material is being discharged too wet, and the damper 16 145 is opened to permit a circulation of hot gaseous fluids and products of combustion through the entire length of the flues 11 and header 12 to further dry the material by direct action of said circulating hot gases and products of combustion.

. combination of a shell, means for rotatably mounting said shell, means for rotating said shell, means for delivering material to be dried to, feeding it through, and discharging it from said shell, a plurality of flues supported within said shell eccentric to its axis of rotation, the front ends of said flues being closed and their; rear ends open, damper means applied to the rear ends of said flues for opening and closing the same, a furnace setting which encloses a section of said shell comprising a fire-box and a.

chamber for hot gaseous fluids and products of combustion, open-ended pipe sections which connect said drier shell with the flues supported therein, respectively, arranged to permit hot gaseous fluids and products of combustion to pass from the furnace into said flues, said flues also being provided with ports for the passage of hot gaseous fluids. and'products of combustion therefrom to the interior of the drier shell, means for imparting a cascading or tumbling movement to material contained in said shell, in operation, and an exhauster for producing a current of hot gaseous fluids through said shell towards and discharging the same at its front end.

2. A rotary drier of the type specified in claim 1, in which a header is mounted within the drier shell adjacent its rear end with which the rear ends of the flues mounted in the drier shell communicate, said header being provided with an opening in its rear side, and a damper which controls saidopening.

3. The rotary drier specified in claim 1, which comprises a header mounted within the shell of the drier adjacent its rear end with which the rear ends of the flues mounted in the drier shell communicate, and which comprises an openended rearward extension, and a damper for opening and closing said extension. I

4. The drier specified in claim 1, in which the flues mounted in .the drier shell are proportioned and arranged to provide passageways between said flues through which, in operation, material contained in said shell may fall through substantially its full diameter.

5. The drier specified in claim 1, in which the ports in adjacent flues mounted in the drier shell h are arranged out of line with each other, transversely of the shell.

PHILIP R. PERKINS.

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