US2059661A - Rotary grate - Google Patents

Description

NOV. 3, C. M, SHOTT ROTARY GRATE Filed Sept. 8, 1934 2 Sheets-Sheet l C. M. SHOTT ROTARY GRATE Nov. 3, 1936.

2 sheets-sheet 2 Filed Sept. 8, 1954 h CMSWZ Patented Nov. 3, 1936 UNITED STATES PATENT OFFICE Kleenburn Stoker Corporation,

Kleenburn,

Wyo., a corporation of Wyoming Application September 8, 1934, Serial No. 743,270

7 Claims.

This invention relates to the class of fuel grates and pertains particularly to an improved rotary grate structure.

The primary object of the present invention is to provide a novel type of rotary grate in which air may be fed through the grate to the fuel thereon but without permitting any of the fuel to pass through the grate structure.

Another object of the invention is to provide 10 an improved form of grate made up of a plurality of coaxially arranged elements of constantly decreasing diameter and maintained in vertically spaced relation so that air may be fed therethrough to fuel deposited upon the surface,

without permitting any of the fuel or ash from falling through into the underlying air supply chambers.

A further object of the invention is to provide an improved grate structure which is designed for rotation to effect a progressive feeding of air therethrough from a point of supply, in which a novel retainer unit is employed for removably supporting the sectionally constructed grate units.

'I'he invention will be best understood from a consideration of the following detailed description taken in connection with the accompanying drawings forming part of this specication, with the understanding, however, that the in- Vention is not confined to any strict conformity with the showing of the drawings but may be changed or modified so long as such changes or modifications mark no material departure from the salient features of the invention as expressed in the appended claims.

In the drawings:-

Figure l is a vertical section on the line I--I of Figure 2, showing the grate structure embodying the present invention with a portion of the grate unit removed and with the structure disposed in the lower part of a conventionally illustrated furnace.

Figure 2 is a view in top plan of a major portion of the grate structure showing sections oi 4 the grate unit removed.

Figure 3 is a sectional View taken upon the n through the grate unit only on the line 'I-'I in Figure 2.

Referring to the drawings, the numeral I indicates the lower portion of a conventionally illustrated furnace structure within which the grate 5 structure embodying the present invention is shown.

The present grate structure comprises a central air supply unit 2 which consists of a lower casing 3 into the side wall of which an air sup- 10 ply pipe 4 extends which may receive air under pressure from any suitable mechanism such as a fan or the like. The casing 3 has an inwardly extending annular top flange 5, and resting upon this flange is the vertically disposed hollow cylin- 15 der 6, which has an outwardly extending surrounding base flange 'I which rests upon the flange 5 and is bolted thereto in the manner illustrated. Surrounding the cylinder 6 and resting upon the flange 'I is an annular bearing metal ring 8, the purpose for which will be hereinafter set forth. The wall of the cylinder 6 is provided with a series of apertures S which extend circumferentially thereof and are of graduated 25 heights from one end of the series to the other so that the amount of air passing through these apertures in progressing from one end of the series to the other, is gradually cut down.

Surrounding the air cylinder 6 is a grate re- 30 taining unit indicated generally by the numeral IU. This unit comprises a circular base plate or floor I I which is centrally apertured to receive the cylinder 6 and is provided at its under side around the central aperture with the thickened 35 bearing portion I2 which rests upon and turns on the ring 8.

Formed integral with the grate retainer unit floor I I is a series of vertically disposed partitions or Webs I6 which extend radially, terminating 40 at their outer ends short of the outer edge of the floor and at their inner ends being spaced to form the necessary .central yunobstructed area into which theair cylinder 6 must extend. The inner edges of these webs or partitions I3 are formed 45 to conform closely to the surface contour of the cylinder 6 and at the center of the retainer unit and above the cylinder 6, they are integrally joined to and connected by the head or cap I4, which rests upon the topof the cylinder 6, as 50 shown in Figure 1 and which has formed integral therewith the upwardly extending central post I5. This post I5 is upon the vertical axis of the cylinder 6 and forms an axis or pivot for the grate structure and for retaining in position thereover the fuel feeding mechanism hereinafter described.

The top edge of each of the walls or partitions I3 is cut out in stepped formation, as indicated at I6, for the purpose of better retaining in position the hereinafter described grate units.

Surrounding the bottom or floor plate I I of the grate retainer unit is a sectional expansion ring I1, the sections of which are joined in overlapping relation, as indicated at I8 in Figure 2. As illustrated in Figure l, a portion of this expansion ring overlies and rests upon the top surface of the floor plate II and at intervals the ring Il has extending inwardly from each of its sections the integral ears I9 which are bolted to the floor plate II, as indicated at 20 in Figure 6.

The expansion ring I'I is formed to provide about its outer edge the upwardly inclined lip 2| which coacts with the adjacent portion of the furnace structure to maintain the fuel and ash on the grate structure. This lip also corresponds with the formation of portions of the grate unit to form the completed grate structure, as will be more fully described.

The grate unit is indicated generally by the numeral 22 and comprises a plurality of annular plates 23, which are coaxially arranged and of varying diameters so that when disposed one above the other with the plate of largest diameter at the bottom of the series, they form an approximately conical structure. These annular plates 23 may be and are illustrated as divided into a number of segments, the number here illustrated being four, although it is to be understood that the plates may be divided into a greater number of segments or need not be divided at all if their assembly and use as an integral unit is found feasible.

For the purpose of maintaining the plates 23 in coaxial relation and in the spaced relation in which they are shown in Figure l, there is joined therewith, or cast integral therewith, the radially disposed ribs 24, 25 and 26. The ribs 24 are relatively wide and heavy, as illustrated in Figure 3,

`- while the ribs 25 are narrower or of less depth and have their under edges cut out or formed in stepped design to conform with and rest upon the steps of the grate retainer webs or partitions I3. Between the ribs 24 and 25 are located the ribs 26 which, as shown in Figure 2, are relatively short, extending radially of the grate unit only a portion of the distance which the other ribs extend.

In the present illustration of the grate unit structure, the same is divided into four sections and in assembling these sections upon the grate retainer I0, the adjoining or abutting edges are formed to provide the coacting channel and tongue 2l and 28, respectively, to form the overlapping joint illustrated in Figure 4.

The ribs 24, 25 and 26 which connect the divided annular grate plates together serve also, as previously stated, to maintain these plates in vertically spaced relation so as to provide the air passageways 29 between the plates. Through these passageways, the air is forced from the areas or chambers formed between the partition plates I3 of the grate retainer structure, and as will be readily apparent, as the grate is rotated, each of certain of these areas between the partitions I3 will receive a different amount of air from the others because of the varying sizes of the air openings 9 formed in the wall of the cylinder 6, before which openings the partitions pass.

As illustrated in Figures l and 2, each of the annular plates 23 of the grate structure has an upwardly inclined top surface extending to its outer edge from a line lying slightly beyond the periphery of the next overlying plate, thus forming a peripheral lip 30. These lips 30 of the grate plates together with the lip 2I of the expansion ring, serve to retain in place fuel which is discharged onto the grate by forming what amounts to a series of annular pockets. In these annular pockets, the fuel lodges and is burned.

In order to further assist in retaining the joined grate plates in position, the bottoms thereof are provided at intervals with downwardly projecting lugs 32 which, as shown in dotted lines in Figure 2, oppose the inner edge of the expansion ring Il, so as to prevent any radial movement of the sections into which the joined grate plates may be divided.

While any satisfactory means of discharging fuel onto the grate may be employed, it is preferred that an endless feed arrangement of the character illustrated in Figure l be used. This feed comprises a tube or casing 33 which is provided with an outlet or discharge opening 34 over the grate and which has at its inner end the ring 35, which receives the post I5. Within the tube 33 is a screw conveyor 36 by which the fuel in the proper condition of neness is fed through the opening 3d. Extending downwardly from the fuel conducting tube 33 is a sweep apron 31, which has its lower edge in close proximity to the grate surface and which serves to wipe off the ash before fresh fuel is added to the grate.

Any suitable means may be employed for rotating the grate structure such, for example, as the annular gear 38 secured to the under side of the grate retainer unit and connected with a pinion 39 which is driven in any desired manner through the medium of the shaft 40.

The fuel feed means, driving means and graduated air supply means here illustrated forms the subject-matter of prior Patent 1,914,873.

What is claimed isz- 1. In a grate structure, a plurality of coaxially arranged annular plates of different diameters arranged in superposed xed relation to form an f approximately conical structure, each of said plates which lies beneath an adjacent plate being of an interior diameter materially less than the outside diameter of the overlying plate whereby an overlap of the plates is formed, and means connecting and securing the plates` in vertically spaced relation whereby horizontal air passages are formed therebetween, each of said annular plates having a top area which is upwardly and outwardly inclined to form a fuel retaining lip, said lip being formed throughout the circumferential extent of the plate and having an interior diameter slightly greater than the overall diameter of the superimposed plate.

2. In a rotary grate structure, a grate unit retainer, comprising a base plate having a central aperture, a plurality of vertically disposed partitions each having a lower edge joined throughout its length with said plate and disposed about and radiating from the aperture and terminating adjacent to the outer edge of the plate, the top edges of said partitions being outwardly and downwardly inclined and in stepped formation, a cylindric vertical structure projecting upwardly through the aperture of said plate and constituting a pivot about which the plate may be rotated,

said partitions abutting and moving about the cylindric structure with the plate, and a grate unit comprising a plurality of vertically spaced coaxially arranged annular members disposed in coaxial relation with the plate and resting upon the stepped surfaces of said partitions.

3. In a rotary grate structure, a grate unit retainer, comprising a base plate having a central aperture, a plurality of vertically disposed partitions disposed about and radiating from the aperture and joined throughout their radial extent with and terminating adjacent to the outer edge of the plate, the top edges of said partitions being outwardly and downwardly inclined and in stepped formation, a cylindric vertical structure projecting upwardly through the aperture of said plate and constituting a pivot about which the plate may be rotated, a plurality of segments of annuli disposed in coaxial stepped relation on the stepped surfaces. of said partitions and coaxial with said base, said segments uniting to form annular members, and rib members connecting said segments and maintaining the same in vertically spaced relation to form air passageways therebetween and against relative movement.

4. In a rotary grate structure, a grate unit retainer, comprising a base plate having a central aperture, a plurality of vertically disposed partitions integral with said plate and disposed about and radiating from the aperture, the top edges of said partitions being outwardly and downwardly inclined and in stepped formation, a cylindric vertical structure projecting upwardly through the aperture of said plate and constituting a pivot about which the plate may be rotated, a grate unit comprising a plurality of vertically spaced coaxially arran-ged annular plates disposed in coaxial relation with the base plate and resting upon the stepped surfaces of said partitions, and a sectional ring encircling said base plate and the outer ends of said partitions and secured to the base plate adjacent the periphery of the same, said ring facilitating expansive movement of the parts without breakage.

5. In a grate structure, a vertically disposed body of circular cross section having an encircling ange at its lower end, a circular plate having a central opening through which said vertical body projects and having a bearing surface upon its under side encircling the opening and resting upon said flange, a plurality of vertically disposed partitions joined to and carried by said plate and extending radially thereof and each having an inner vertical edge in wiping contact with said vertical bodyl and further having its top edge inclined downwardly toward the outer edge of the plate and formed into a series of steps, said plate having its periphery beyond the outer edges of the partitions, a plurality of grate plates of annular configuration, disposed coaxially with one another and with the vertical body, said plates being of different diameters and resting upon the stepped top edges of said partitions to form a substantially conical structure, means securing said grate plates together in vertically spaced overlapping relation, and means for rotating the base plate and elements supported thereby about the vertical body, said vertical body being formed to facilitate the discharge of air therethrough into the areas between the said partitions.

6. In a grate structure, a vertically disposed body of circular cross section having an encircling flange at its lower end, a circular base plate having a central opening through which said vertical body projects and having a bearing surface upon its under side encircling the opening and resting upon said flange, a plurality of vertically disposed partitions carried by said plate and extending radially thereof and each having an inner vertical edge in wiping contact with said vertical body and further having its top edge inclined downwardly toward the outer edge of the plate and formed into a series of steps, a plurality of grate plates of annular configuration and of different diameters, disposed coaxially with one another and with the vertical body and resting upon the stepped top edges of said partitions to form a substantially conical structure, means securing said grate plates together in vertically spaced overlapping relation, means for rotating the base plate and elements supported thereby about the vertical body, said vertical body being formed to facilitate the discharge of air into the areas between the said partitions, and an upstanding lip formed at the outer edge of each grate plate and projecting upwardly to a plane lying above the bottom of the next overlying grate plate.

7. In a grate of the character described, a vertically disposed central body of circular cross section and having a surrounding flange at its lower end, a circular base plate having a central opening through which the vertical body projects, having a bearing surface on its under side and surrounding the aperture and resting upon said flange, a segmental annulus secured to the top of said plate about its outer edge, a plurality of vertically disposed partitions carried by the plate and extending radially thereof from the central body and having wiping contact with the latter, each of said partitions being of gradually decreasing height from its inner to its outer end, a, grate unit comprising a plurality of sections each consisting of a series of arcuate grate plates of different diameters arranged in overlapping vertically spaced relation about a common axis and means securing the grate plates together in spaced relation whereby the unit assumes a substantially conical form, said sections being supported upon said partitions and joined to .form a coaxially arranged series of annular members, means forming a part of each section having abutting relation with the said segmental annulus for retaining the sections in position and means for rotating the partition supporting plate, said central body being adapted to facilitate the discharge of air into the areas between the partitions.

CHRISTIAN M. SHOTT.

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