US2349755A - Furnace construction - Google Patents

Description

y 3, 1 v e. P. PRATHER 2,349,755

FURNACE CONSTRUCTION Filed Feb. 3, 1943 t INVENTOR.

GRAHAMPP'PA 7715?.

12M OWJ QW ATTORNEVJ Patented May 23, 1944 UNITED FURNACE CONSTRUCTION Graham P. Prather, Teaneck, N. J., assignor to Nichols Engineering & Research Corporation, New York, N. Y., a corporation of Delaware Application February 3, 1943, Serial No. 474,504

3 Claims.

This invention relates to furnace constructions and more particularly to arrangements for rotatably mounting the rabbling structure in furnaces such as of the type disclosed for example in U. S. patent to Charles W. Nichols, No. 2,232,556, granted February 18, 1941. In furnaces of such type, a hollow perforated structure such as a cone, accompanied if desired by rabble arms or the like, is mounted to rotate in the fire bed above a hearth, the interior of the structure being connected to an air supply whereby air is distributed through the perforations into the material being burned, while at the same time the material is agitated or advanced over hearth and grate areas.

- The objects of the present invention include the provision of improved supporting and bearing constructions and arrangements for such rotatable structures, which will be relatively inexpensive and easier to construct and erect, and more dependable in use.

Various further and more specific objects, features and advantages will more clearly appear from the detailed description given below taken in connection with the accompanying drawing which forms a part of this specification and illus trates merely by way of example, a preferred form of the invention. The invention consists in such novel features, arrangements and combinations of parts as may be shown and described in connection with the apparatus herein disclosed.

The drawing comprises a vertical sectional view of the present preferred embodiment of the invention.

A central circular fixed hearth area is shown at In which may be surrounded by a grate area, portions of which are shown at H, formed if desired of movable sections. Material which is to be heated or burned, such for example as waste material which is to be incinerated, is charged on to the hearth area ill so as to cover and surround an upstanding generally sonically shaped rotatable hollow member as at l2. This member may have attached thereto a pair of generally tangentially extending arms as at I3 and I4, rotatable with the member It for agitating the material being burned or treated and for gradually advancing the same from the hearth area II] on to the grate areas H, as is more fully explained in the above mentioned Nichols patent.

While the invention will be described with particular reference to the type of furnace disclosed in said Nichols patent, it will be understood that the principles of the invention are applicable for the support of the rotating rabbling structure of various other types of furnaces having one or more hearths.

For supporting the rotatable assembly, an upstanding rigid hollow post-like member I5 is provided having a heavily flanged base It adapted to be bolted to portions of a platform, foundation or other structure as at ll. The lower end of this post is arranged to communicate with a pipe H! which extends from a suitable source, not shown, for supplying a current of air flowing up through the post into the member 12 and out through perforations or apertures as at l9, and if desired also, out through apertures in the arms l3, Hi, into the material being burned or treated, the directions of the air currents being as indicated by the arrows on the drawings.

The exterior surfaces of the'post l5 as shown may be formed with upper and lower journal bearing areas as at 20, 2|. A rotatable hollow cylinder or shaft 22 is adapted to slide down into position over these journal bearing areas. The upper end of the shaft 22 may be welded or other wise secured to a protrudingflange 23, which flange in turn may be removably secured as by bolts 24 to an inwardly protruding annular flange area 25 formed within the base of the cone member I2. Th same bolts 24 may also be used to secure to the upper surfaces of the flange 25 an annular thrust bearing plate 25 formed with a bearing raceway 21 and for cooperating with an annular inwardly extending flange 28 having a complementary bearing raceway as shown, the flange 23 being formed integral with the upper end of the post member l5. annular cavities of semi-circular cross section may be formed at the abutting surfaces of the bearing flanges 26 and 28, inside th raceway as shown at 29, for receiving a suitable packing ring such as one formed of graphite and asbestos.

To facilitate removal of the bolts 24 without breakage after considerable heating and use, these bolts instead of being formed with conventional heads are preferably formed with slots to receive wedge members as at 30. Thus to separate the cone structure I 2 from the flange 23 and from the thrust bearing plate 26, it is merely necessary to knock out the wedges 3B, whereupon the parts may be readily slid off the bolts.

It will be apparent that the above described thrust bearing structure will serve to support all or a greater part of the weight of the rotatable structure, and since this is an annular bearing with a relatively large current of air flowing therethrough, the bearing will at all times be susceptible to adequate cooling by the air current.

In order to maintain proper lubrication of the journal bearings 29, 2 i, as well as the thrust bearing at 21, two or more grease pipes as at 3! may extend up into the hollow post 22 and be brought into communication with the bearings as by coupling means 32. Since all portions of these grease pipes and couplings which might otherwise become heated, are located within the air stream, they may therefore be effectively cooled by the Complementary l air, thus preventing too ready flow or destruction of the lubricant. At the same time, the rigid hollow supporting post l5 will serve to enclose and protect the grease connections against any possibility of injury such as when the rotatable renairs.

Power for rotating the above described rotatable structure may be supplied by a shaft 33 connected to a suitable source of power, not shown, and carrying a bevel gear 34 for cooperating with a large bevel gear 35 clamped or otherwise mounted on the exterior of the hollow cylinder or shaft 22. To compensate for the upward thrust of the bevel gear 34 against one side of the gear 35, a conical roller 36 may be mounted at the opposite side of the gear 35 having supporting engagement with a conical peripheral area 31 on the gear 35.

One of the important considerations with the bearing structure for furnaces of this type is the matter of excluding dust, fine ashes or the like from entrance into the bearings. With the above described arrangement it will be noted that the hollow cylindrical rotatable member 22 effectively serves as a housing, preventing the entrance of any falling dust into journal bearings 20, 2 l Also the above described flanged connection structure at the top of the post l5 serves as a housing enclosing the thrust bearing at 21. The pressure of the air streams further serves to force outwardly through any crevices between the flanges, dust which otherwise might enter the bearings. To further insure against entry of dust into the bearings, an annular ring of asbestos or other suitable packing material may be provided as at 38 encircling the rotatable cylinder 22. The lower side of this packing may be held in place as by an annular plate 39 bolted as shown, or otherwise secured to supporting bars as at 40 or other parts of the hearth [0. The outer edges of the packing ring 38 may be retained by a cylindrical sheet metal member as at 4| formed as shown with an inturned flange adapted to be secured by the bolts 24 in between flanges 23 and 25. The cone structure l2 may also be formed at its base with air outlets as at 42, so positioned as to direct jets of air outwardly from the base of the cone to thereby cool the thrust bearing externally, and blow dust away.

To further protect the bearing structures and the gearing against access of dust, ashes, etc., an enclosing housing as at 43 may be provided beneath the hearth Ill.

In erecting the structure shown, it will be apparent that the housing 43 and the hearth and grate areas l3 and II may first be put in place. Then the post l5 may be bolted in position, al though, its exact position with respect to the hearth does not have to be determined with precision. Thereafter the rotatable structure (except for the gear 35) may be lowered into position as an assembled unit. Or if the hearth areas are installed afterwards, the rotatable structure including the gear 35 may all be lowered into place as an assembled unit. Since all of the stationary bearing surfaces for both the journal bearings and the thrust bearing, are integral with the post I5, no difliculties of aligning the bearings are involved. Formation of all of the stationary bearing surfaces integral with the one supporting post I5 also simplifies and ministructure is being put into place or removed for mizes the expense of the bearing manufacture and simplified the problem of using the stream of cooling air for purposes of cooling the bearings.

The above described arrangement of the journal bearings also makes it possible to use these bearings as an effective double seal against the escape of air under pressure from between the rotatable parts and the stationary supporting structure. Thus the use of any separate rotatable sealing means for conducting the air into the rotatable structure is avoided, as the accurately fitted bearing areas at 20, 2| themselves will eifectively provide a double seal.

This novel bearing arrangement has the further advantage that all of the stationary bearings being integral with the post l5, may be rigidly supported directly fromthe floor or foundation structure of the furnace quite independent of the hearth and grate areas. This not only makes for a more rugged construction, but permits the hearth and grate areas to be easily repaired or replaced if desired without disturb ing the rotatable structure.

While the invention has been described in detail with respect to a particular preferred example, it will be understood by those skilled in the art after understanding the invention that various changes and modifications may be made without departing from the spirit and scope of the invention, and it is intended therefore in the appended claims to cover all such changes and modifications. i

What is claimed as new and desired to be secured by Letters Patent is:

1. In a furnace construction, a stationary upstanding hollow post, a rotatable tubular member journaled thereon, a hollow rabbling and air distributing device fixed upon the upper end of said tubular member to rotate therewith, means for supplying a stream of cooling air up through said post into said device, whereby such streamalso serves to cool the post and the journal bearings thereon, and grease conduit means extending up within said post to such bearings, whereby said conduit means are also cooled by said stream.

grease conduit means extending up within said post to said bearing whereby said conduit means is cooled by said stream.

3. In a furnace having a hollow rotatable apertured cone-like structure with rabbling meansmounted in the fire bed for agitating same and distributing air therein, a stationary upstanding hollow supporting post beneath said structure,

and communicating with the hollow space therein for providing an air supply thereto, the upperend of said post being formed with a thrust bearing raceway, an annular flange detachably secured within the bottom of said structure and formed with a complementary raceway, and annular journal bearing means detachably secured to the under side of the bottom of said structure and rotatably embracing said post.

GRAHAM P. PRATHER.

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