US 2380630 A
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Description (OCR text may contain errors)
July 31 1945 R. c. cRoss 2,380,630
EMERGENCY GRATE Filed OGL. 8.; 1942 2 Sheets-Sheet 2" Patented July 3l, 1945 EMERGENCY GRATE Robert C. Cross, Riverside, Ill., assignor to Sears, Roebuck and Co., Chicago, Ill., a corporation of New York Application October 8, 1942, Serial No. 461,296
This invention relates to emergency grates such as those employed in converting oil burners to use with coal or other solid fuel burners.
The term furnace is hereinafter used for convenience to denote heating plants generally, whether they be hot water or steam heating boilers or warm air furnaces.
It is an object of the invention to provide a conversion grate so constructed as to lbe usable in hea-ters or heating plants Varying widely in furnace chamber sizes.
A further object is to provide a plurality of interchangeably interiitted grate parts whereby a grate may be assembled in various Shapes and sizes and installed inany of a variety of furnace chamber shapes and sizes.
An additional object is to provide a conversion grate having frangible or severable portions enabling the grate to be reduced in size by breaking off sections to fit a selected size of furnace chamber.
Another object is to provide a conversion grate unit constructed to enable the fuel to be burned i well beyond the re bed area of the original oil burner element but instead more totally extensive with the walls of the furnace chamber.
Further objects and advantages of the invention will appear as the description proceeds.
The invention will be better understood upon reference to the following description and accompanying drawings in which:
Fig. 1 is a fragmentary vertical sectional view taken as indicated by the line I-I in Fig. 2.
Fig. 2 is a plan sectional View taken as indicated by the line 2 2 in Fig. 1.
Fig. 3 is a fragmentary plan view of separated complemental grate parts appearing in assembly in Fig. 2.
Fig. 4 is a vertical sectional view taken as indicated at 4 4 in Fig. 3 and showing how the complemental parts may be brought into assembly.
Fig. 5 is a sectional View taken as indicated at 5-5 in Fig. 3.
Fig. 6 is a sectional view similar to Fig. 5 but shows the parts assembled.
Fig. 7 is a fragmentary plan view, similar to Fig. 2 but without the spacer or leaf, and with the parts reduced in area to t a smaller furnace chamber.
Fig. 8 is an enlarged fragmentary sectional view taken as indicated by the line 8-8 in Fig. 7. l
Fig. 9 is a fragmentary inverted plan View of the grate shown in Fig. 7.
Fig. 10 is an enlarged fragmentary sectional view taken as indicated by the line I -I0 in Fig. 2.
Fig. 11 is a side elevation of the leaf inserted casting taken as indicated by the line II-II in Fig. 2.
Fig. 12 is a transverse sectional view showing a blower in an installation equipped with one embodiment of the invention.
Fig. 13 is an enlarged fragmentary end elevational view taken as indicated by the line I3-I3 in Fig. 2, but with certain of the parts separated.
Fig. 14 is a view similar to Fig. 3 but of a modication.
Referring now more particularly to the drawings, the grate structure in accordance with my invention may comprise a pair of substantially semicircular members I5. Each member I5 may be of stepped, cascaded or terraced formation, comprising an upper central portion I6, and circuxnferential steps I8 of progressively increasing diameter downward, terminating at the outer periphery in a depending flange I9. The outer peripheries of the steps are selected in accordance with standard furnace chamber dimensions, the construction being such that, as will appear, the size may be readily reduced to the desired area by the user.
For the introduction of primary air to the fuel adapted to be burned over the grate, each grate member is provided with numerous openings. Said openings may be disposed in any desired location and arrangement, that disclosed here being illustrative. 'I'he openings 2I in the relatively horizontal portions of the steps are preferably arranged to provide at suitable intervals bridging portions 22 having score grooves or weakening notches 24, said notches being sufficiently deep and said portions being sufficiently short so that the user, with the aid of a chisel, can readily sever each portion thus weakened, and by repeating this operation at every such portion yin the same circumferential series remove the portion outward of such series. This operation may be performed on each grate casting or forging, whereupon the members may be readily inserted into the users furnace and assembled over the oil burner combustion chamber (Fig. 7).
The diametral margin of each member I5 comprises two portions 28 and 29, offset from each other, both vertically and horizontally, affording a recess 3| over the portion 28, said recess terminating inwardly at a wall 32 adjacent but short of the center of the member. The free edge 33 of said wall 32 may be ush with the free edge 35 of the depressed portion 28 and terminates on the other side of the center a distance substantially equal to the distance of said recess 3l from the center, at a horizontally offset shoulder 38 forming the inner terminus of the undepressed mar ginal portion or lip 29. The free edge 39 of the lip 29 and the side wall 4I of the depression 3I are disposed on opposite sides of and equi-distant from the diametral plane containing the edges 33 and 35.
A hole 43 may be formed in one of the marginal portions, such as the portion 28, and a pin 45 formed in the lip 29. In assembling the members, they are disposed with their diametral margins crossed (Fig. 4) in such manner that each lip 29 overlies the depressed portion 28 of the companion member, with the pins 45 slightly entered or disposed to readily enter the cooperating holes 43. Then, as the members are relatively swung to lie ush with each other, the lip 29 of each comes to rest in the depression 3| of the other and the respective pins are fully entered in the respective holes, so that the members are locked together as a unit operative just as though they were cast in one piece, except for necessary clearance between pins and holes.
If desired, the pins 43 and holes 45 may be omitted, in which event the members may be placed on the support in the furnace and simply slid into assembly, the lip 29 of each member telescopically entering the depression 28 of the other until the members are in abutment as in Figs. 2 and '1.
Each member I5 may be provided with reinforcing ribs 46 reinforcing the various steps I8, and with additional ribs 41 reinforcing the top I6. The edge flange I9 serves the purpose among others, of preventing warp of the outer portion of the casting and affording edge reinforcement therefor in service. i,
The openings 2l servenot only to weaken the steps I8, but to admit air for combustion of the solid fuel supported by the grate. Additional openings 48 at the junctures of the steps I8 and Y openings 49 in the top I6 are provided to insure an adequate air supply.
' Furnace retort openings and oil burner combustion chambers are conventionally round, obround, square or rectangular. The round grate just described may be suitable for any furnace wall and combustion chamber shapes.
For an elongated furnace, or one having an elongated combustion chamber, I may provide, in addition to the aforesaid semicircular members I5, interchangeable leaves or spacers 5I of generally rectangular form, each leaf being formed at each of its longitudinal margins with a lip 29 and a depression 3I in conformity with the aforesaid margins of the semicircular grate members I5, the margins being interchangeable. Thus if only one such spacer is used it can be assembled with each of the semi-circular members I5 in exactly the manner described above (Fig. 2). If two or more leaves are to be employed, it is obvious how they may be readily assembled with one another and with the semi-circular members l5.
It will be observed thatlike the end members I5, the spacers 5I are formed with holes 2l, 48 and 49 for admitting primary air supply and with frangible portions 53 adapted to form continuations of the series of such portions 22 in the members I5, so that the spacer per.pheries may be broken olf in conformity with the reduction in size of the end members I5, whereby the spacers in assembly with the end members may provide a. continuous periphery. The spacers may be provided with holes 43 and pins 45, or these may be cordance with my invention may be installed for use. To this end, I have shown a furnace combustion chamber having a wall 5S and an oil burner combustion chamber 68 which is converted to use with solid fuel such as coal. Accordingly, the oil burner electrode-and-nozzle assembly are removed, and the oil pump and ignition wiring disconnected, leaving the air tube 69 equipped with a `fan 1I for blowing primary air into the oil burner combustion chamber. Suitable heat insulation 12, such as rock wool or other material, is packed in the space between the furnace foundation wall or ash pit 66 and the oil burner combustion chamber, an annular sheet 14 of asbestos, metal, or other suitable material being applied to the top of the insulation and oil burner combustion chamber wall to provide a Vfloor or support for the grate. If desired, the floor may be formed by a cement covering over the rock Wool or other filler, and substantially flush with the top of the oil burner combustion chamber.
The parts of the grate, reduced to the desired size if necessary, that is, the maximum size to which it can be reduced and still fit in a given furnace chamber, as explained above, are then inserted through the fire door or other suitable opening and assembled as explained above. The assembled grate unit is then adjusted so that its periphery is substantially uniformly spaced from the interior wall 11 of the combustion chamber. Refractory cement or clay 18 is then applied at the periphery of the grate to seal its juncture with the floor 14, so that excess leakage of primary air from the plenum space 19 beneath the grate will be precluded and at the same time the grate will be retained in the desired position. If the grate is not reduced, its depending peripheral flange I9 will rest on the floor 14 as shown in Fig. l. If the grate is of reduced size lFigs. 7 and 8), the outermost horizontal portion 83 of the grate may be spaced from the door 14 by the depression 28 and pins 85, Fig. 9, formed on the bottoms of the steps, the bottoms of the pins being in the same planes as the respective bottom surfaces of the depression 28 formed on the same member.
1n use, solid fuel such as coal is fed onto the grate, and inasmuch as the grate has openings therethrough substantally to the outer periphery thereof, the primary air blown in by the fan will mushroom from the top of the oil burner cornbustion chamber, and reach all of the coal on the grate through said openings and thus all of the coal on the grate will be burned evenly. Accordingly, my invention affords in effect a plenum chamber extending a substantial distance laterally beyond the rim of the oil burner combustion chamber.
This is a substantial improvement over past grates in this respect, such grates providing for the burning of only that portion of the coal which is directly over the oil burner combustion chamber.
The two end members being identical, and
therefore interchangeable, and the same being true for the spacers, and in view of the formation of the parts which adapts them to form units to t various sizes of furnace Walls, it is apparent that I have provided a conversion grate con struction of extremely low cOst which makes it a simple and inexpensive matter in .a time of economic shortage, to convert oil burners to solid fuel burners. Y
For reconversion to oil burning, it is an easy matter to remove the refractory, separate and remove the grate parts and Ireinstall the oil burner apparatus.
Various modications coming Within the spirit of my invention may suggest themselves to those skilled in the art, and hence I do not wish to be limited to the specic form shown or uses mentioned, except to the extent indicated in the appended claim, which is to be interpreted as broadly as the state of the art will permit.
A solid fuel conversion grate, comprising a pair of semi-circular castings, each having two edge formations oppositely offset from a diametral line `constituting a median junction between said castings and meeting at a midpoint of said line, one of said edge formations of each casting being throughout recessed to receive the non-recessed edge formation of the other of said castings during intertting placement of said castings one with the other, a series of cascaded semi-circular sections integral with each of said castings having progressively larger diameters and progressively loWer planes in horizontal correspondence, said edge formations defining said cascaded sections,
v and an optionally insertible intermediate casting having edge formations complementary to those of its adjacent semi-circular casting and correspondingly oiset so as to afford elongation to said conversion grate in a direction transverse of said diametral line.
ROBERT C. CROSS.