US3413938A - Stoker construction - Google Patents

Description

Dec. 3, 1968 M. DVIRKA v 1 STOKER CONSTRUCTION Filed April 12, 1967 6 Sheets-Sheet 2 fll/ Muzo Dvu zxA ATTORNEY 5 M. DVIRKA Dec. 3, 19 8 STOKER CONSTRUCTION 6 Sheets-Sheet 3 Filed April 12, 1967 INVENTOR ATTORNEYS Dec. 3, 1968 Filed April 12, 1967 M. DVIRKA STOKER CONSTRUCTION 6 Sheets-Sheet 4 INVENTOR Muao bvuzmx JZMW ATTORNEYS M. DVIRKA STOKER CONSTRUCTION 6 Sheets-Sheet 5 Dec. 3, 1968 Filed April 12, 1967 ITUHIII INVENT OR M nae b VI RKA BY m Q $OILJ#MUJUIQQ M me.

ATTORNEYS Dec. 3, 1968 M. DVIRKA 3,413,938

STOKER CONSTRUCTION Filed April 12, 1967 I 6 Sheets-Sheet 6 88 INVENTOR 1 M l 2.0 DvuaK ATTORNEYS United States Patent 3,413,938 STOKER CONSTRUCTION Miro Dvirka, Long Island City, N.Y., assignor to Hagan Industries, Incorporated, Corona, N .Y., a corporation of New York Filed Apr. 12, 1967, Ser. No. 630,412 6 Claims. (Cl. 110-38) ABSTRACT OF THE DISCLOSURE A stoker construction for burning refuse in an incinerator including a plurality of stationary grates and a plurality of movable grates arranged along an inclined plane, which grates coact upon reciprocating the movable grates to cause a tumbling action of the refuse as it is conveyed from the charging end of the stoker to the ash removal end thereof, thus exposing and subjecting a maximum area of such refuse for reduction by combustion.

Background of the invention This invention relates to a stoker construction and more particularly to a reciprocating type of stoker construction.

In the prior art most reciprocating type stoker constructions have been provided with a plurality of movable grates arranged along a line of travel in an incinerator, which are reciprocated to convey refuse from the charging end of the stoker to the ash removal end thereof. The reciprocating action of the grates primarily serves a two-fold purpose in stoking the refuse and conveying it through the incinerator. Reciprocating stokers have proven relatively effective in burning refuse, in that the refuse is upset as it is conveyed through the incinerator, thus exposing and subjecting otherwise inaccessible portions of the refuse to combustion.

It has been found, however, that although conventional stokers have been satisfactory in providing a fairly effective stoking action for burning small masses of refuse, such stokers have not been effective in satisfactorily stoking relatively large masses of refuse and particularly compacted or interwoven masses of refuse which commonly are charged into large capacity incinerators such as commercial, industrial and municipal incinerators. Large compacted or interwoven masses of refuse charged into incinerators provided with conventional type reciproeating stokers, usually are conveyed from the charging end to the ash removal end of the stokers without burning completely. This has resulted in large ash residue, which is undesirable. Such large ash residue presents problems in the disposing of the residue, and also in possible damage to conveyors and other mechanisms utilized for ash removal.

Objects of the invention The principal purpose of the present invention is to provide the novel stoker construction.

Another object of the present invention is to provide a novel reciprocating type of stoker construction.

A further object of the present invention is to provide a novel reciprocating stoker construction suitable for use in incinerators for stoking and conveying large masses of refuse which is effective in exposing and subjecting maximum areas of such masses for burning.

A still further object of the present invention is to provide a novel reciprocating stoker construction which is effective in stoking compacted or interwoven masses of refuse.

Another object of the present invention is to provide a novel reciprocating stoker construction which is effective in tumbling refuse as the refuse is conveyed from the charging end to the ash removal end of the stoker.

A further object of the invention is to provide a novel reciprocating stoker construction which is effective in exposing and subjecting a maximum area of refuse for maximum reduction of the refuse by burning, thus eliminating or at least significantly reducing the amount" of large masses of ash residue.

A still further object of the present invention is to provide a novel reciprocating stoker construction which is relatively simple in construction, comparatively inexpensive to manufacture and operate, and comparatively inexpensive to maintain.

Other objects and advantages of the invention will become more apparent to those persons skilled in the art, from the following description of a. practical embodiment thereof, when taken in conjunction with the accompanying drawings which form a part of this specification.

Brief description of the drawings FIGURE 1 is a top plan view of an embodiment of the invention, having a portion thereof broken away.

FIGURE 2 is a cross-sectional view taken along line 2-Z in FIGURE 1.

FIGURE 3 is a cross-sectional view similar to FIG- URE 2, illustrating certain components of the embodiment in sequential positions.

FIGURE 4 is a cross-sectional view taken along line 4-4 in FIGURE 2.

FIGURE 5 is an enlarged cross-sectional view taken along line 55 in FIGURE 2, wherein certain grates have been omitted for the purpose of more clearly il' lustrating certain interior portions of the embodiment.

FIGURE 6 is a perspective view of a subassembly of the embodiment, illustrating the mounting of the stationary and movable grates relative to each other.

FIGURE 7 is a perspective view of a pair of grates utilized in the embodiment.

FIGURE 8 is a perspective view of a modified construction of the grates utilized in the embodiment.

FIGURE 9 is an enlarged cross-sectional view taken along line 9-9 in FIGURE 8.

Description of the preferred embodiment Briefly described, the present invention relates to a stoker construction generally comprising a support means, a plurality of stationary grates mounted on the support means, spaced along an inclined plane, a first plurality of movable grates, spaced along the inclined plane of the stationary grates and disposed between a first set of alternate spaces between the stationary grates, a second plurality of movable grates, spaced along the inclined plane of the stationary grates fand disposed between a second set of alternate spaces between the stationary grates, wherein movable grates are disposed above and below each stationary grate and means for reciprocating the movable grates. Inithe preferred embodiment of the invention, the stationary grates lie in parallel planes, the first and second pluralities of movable grates are reciprocated in opposite directions simultaneously, in planes parallel to the planes of the stationary grates, and the forwardly disposed ends of each of the movable grates is movable along a line of travel between the forwardly disposed ends of successive stationary grates whereby traveling steps elfectively are produced along the length of the stoker, thereby causing refuse charged onto the stoker to tumble as it is conveyed from the charging end to the ash removal end of the stoker.

Referring to the drawings, there is illustrated the preferred embodiment of the invention. FIGURE 1 illustrates a support frame structure mounted within an incinerator which includes a front wall 11, a rear wall 12 and spaced parallel side walls 13 and 14 having longitudinally inclined upper edges. The side walls 13 and 14 are provided with buttress support by means of reinforcing brackets 15 and 16. Mounted along the upper edges of side walls 13 and 14 are sets of transversely spaced brackets 17 on which there are rigidly mounted transversely disposed, longitudinally spaced beams 18, As best illustrated in FIGURES 2 and 3, the beams 18 lie in a longitudinally inclined plane.

Disposed below the rigidly secured cro s beams 18 and between the side walls 13 and 14 of the support frame, is a first carriage assembly 19. This assembly is dispo ed in a longitudinally inclined plane substantially parallel to the plane in which the cross beams 18 lie, and includes a pair of longitudinally dispo ed beam members 20 and 21 interconnected by means of a plurality of cross beam members 22. Mounted on the longitudinally disposed beam members 20 and 21 are longitudinally spaced, upstanding brackets 23 which support a plurality of transversely extending, longitudinally spaced CIO'TS beam members 24. The cross beam members 24 also lie in a longitudinally inclined plane disposed parallel with the plane in which the rigidly secured cross beam members 18 lie.

The carriage assembly 19 also is provided with longitudinally spaced pairs of shoes 25 which are slidably mounted on longitudinally spaced pairs of support brackets 26 which are rigidly secured to the side walls 13 and 14 of the support frame, as best illustrated in FIGURES 2, 3 and 5. Each of the support brackets 26 is provided with an inclined support surface 27 on which a sliding planar surface 28 on a corresponding shoe 25 is seated. The support surfaces 27 are substantially parallel and lie in parallel planes intersecting the longitudinally inclined plane in which the rigid cro s beam members 18 lie. It will be appreciated that upon applying a force along the longitudinal direction of the carriage assembly 19, the assembly 19 will be caused to move as a unit along a line of travel substantially parallel to the support surfaces 27 on the support brackets 26 as a result of a camming action.

Similarly disposed below the rigidly secured cross beams 18 and between the side walls 13 and 14 of the support frame is a second carriage assembly 29. This asiembly is disposed in a longitudinally inclined plane substantially parallel to the planes in which the cross beams 18 and the first carriage assembly lie, and includes a pair of longitudinally disposed beam members and 31 interconnected by means of a plurality of cr0*s beam members 32, as best illustrated in FIGURE 4. It further will be noted in FIGURES 2, 3 and 4 that the carriage assembly 29 is disposed below and lies within the lateral dimension of the carriage assembly 19. Mounted on the longitudinally disposed beam members 30 and 31 are longitudinally spaced, upstanding brackets 33 which support a plurality of transversely extending longitudinally spaced cross beam members 34. The cross beam members 34 also lie in a longitudinally inclined plane disposed parallel to the plane in which the rigidly secured cross beam members 18 lie. In addition, the rigidly mounted cross beam members 18 and the movable cross beam members 24 and 30 are disposed substaitially parallel to each I ther.

Similar to the carriage assembly 19, the carriage assembly 29 is provided with longitudinally spaced pairs of shoes 35 which are slidably mounted on longitudinally paced pairs of support brackets 36 rigidly secured to the side walls 13 and 14 of the support frame, as best shown in FIGURES 2, 3 and 5. The support brackets 36 are provided with inclined support surfaces 37 on which sliding planar surfaces 38 on corresponding shoes 35 are seated. The support surfaces 37 are substantially parallel and lie in parallel planes intersecting the longitudinally inclined plane in which the rigid cross beam members 18 lie. The inclined surfaces 37 also are substantially parallel to the inclined surfaces 27 On support brackets 26. It will be noted that upon applying a force along the longitudinal direction of the carriage assembly 29, the assembly will be caused to move as a unit along a line of travel substantially parallel to the support surfaces 37 on the support brackets 36.

Mounted on each rigid cross beam member 18 is a set of stationary grates 39. Each set of grates 39 consists of a plurality of grates 39a which extend across the entire width of the stoker, as best illustrated in FIGURE 1. Mounted on each of the movable cross beam members 24 of the carriage assembly 19 is a set of movable grates 40. The sets of movable grates 40 are disposed in a first set of alternate spaces between the sets of stationary grates 39. Each set 40 consists of a plurality of grates 40a which are disposed along the entire width of the stoker, as illustrated in FIGURE 1. Each grates 40a is interpcsed between successive stationary grates 39a, is supported at the rearward end thereof on a cross beam member 24, and is seated at its forward end on a stationary grate 39a. This is best illustrated in FIGURES 2, 3 and 6.

Similarly mounted on each movable cross beam member 34 is a set of movable grates 41. The set of movable grates 41 are disposed in a second set of alternate spaces between the sets of stationary grates 39, each consisting of a plurality of movable grates 41a disposed across the entire width of the stoker, as illustrated in FIGURE 1. Each grate 41a is interposed between successive grates 39a, is supported at the rearward end thereof on a movable cross beam member 34, and is supported at the forward end thereof on an adjacent stationary grate 39a. AS can be seen in FIGURES 2 and 3, the sets of stationary grates 39 are spaced along an inclined plane, the sets of movable grates 40 are disposed in a first set of alternate spaces between the sets of stationary grates 39, and the sets of movable grates 41 are disposed in a second set of alternate spaces in the sets of stationary grates 39.

The carriage assemblies 19 and 29 are adapted to be reciprocated by means of driving mechanisms 42 and 43. The driving mechanism 42 consists of a fluid cylinder assembly, including a cylinder member 44 pivotally mounted between two laterally spaced brackets 45 and 46 rigidly secured to the rear wall 12 of the support frame, and a rod member 47 which extends through an opening in the rear wall 12 of the support frame and is pivotally connected at the forward end thereof to the carriage assembly 19. The drive mechanism 43 is disposed below the mechanism 42 and also consists of a fluid cylinder assembly, including a cylinder member 48 pivotally secured to the brackets 45 and 46, and a rod member 49 which extends through an opening in the rear wall 12 of the support frame and is pivotally connected at its forward end to the carriage assembly 29.

The cylinder members are connected to a source of fluid under pressure by means of suitable fluid lines, including controls, whereby the driving mechanisms 42 and 43 can be operated to reciprocate the carriage assemblies 19 and 29 in opposite directions simultaneously. Referring to FIGURE 2 of the drawings, the carriage assembly 19 is illustrated in its forwardmost position. The sets of movable grates 40 simultaneously are in their forwardmost positions with their sloping front face surfaces disposed in alignment with the sloping front surfaces of alternate sets of stationary grates 39, beginning with the first set of grates 39 at the lower right end in FIGURE 2. Also referring to FIGURE 2, the carriage assembly 19 is illustrated in its rearmost position, wherein the sets of movable grates 41 correspondingly are in their rearmost positions with their sloping front surfaces disposed in alignment with the sloping front surfaces of alternate sets of stationary grates 39, beginning with the third set of stationary grates 39 from the lower right end of the support frame illustrated in FIGURE 2. It will be noted with the sets of movable grates positioned as illustrated in F1G- URE 2,a series of steps or a cascaded configuration will be formed along the length of the stoker. These steps also will lie along a longitudinally inclined plane.

FIGURE 3 illustrates the carriage assembly 19in its rearmost position and the carriage assembly 29 in its forwardmost' position. Under such conditions, the sets of movable grates 40 will be in their rearmost positions with their sloping front surfaces disposed in alignment with the sloping front surfaces of alternate sets of stationary grates 39, beginning with the second set of stationary grates 39 from the lower right end ofthe stoker. Simultaneously, the sets of'movable grates 41 will be in their forwardmost positions with their sloping front surfaces disposed in alignment with the sloping front surfaces of alternate sets of stationary grates 39, beginning with the second .set of alternate grates 39 from the lower right end of the stoker. With the carriage assemblies positioned as illustrated in FIGURE 3, the sets of movable and stationary grates form a series of steps along the length of the stoker, which are displaced longitudinally relative to the series of steps formed when the carriages are in the positions illustrated in FIGURE 2. By reciprocating the carriage assemblies in opposite directions simultaneously, the alternate series of steps along the length of the stoker are formed. As a result of the formation of these alternateseries of steps, refuse deposited on the stoker will be caused to cascade and tumble along the length of the stoker from the charging end to the discharge end thereof. This tumbling action of the refuse is caused by the formation of the series of steps along the length of the stoker and the force of gravity.

It will be appreciated that as the drive mechanisms 42 and 43 reciprocate the carriage assemblies in opposite directions simultaneously, the carriages will be moved along lines of travel disposed substantially parallel to the surfaces 27 and 37 on support brackets 26 and 36. Simultaneously, the sets of movable grates 40 and 41 are movable between successive sets of stationary grates 39 along lines of travel disposed substantially parallel to the surfaces 27 and 37 of support brackets 26 and 36. It also will be noted that the sloping front surfaces of each set 1 of movable grates moves along a line of travel between struction to a movable grate 41a. The stationary grate 39a-includes a top wall 50, a rear end wall 51, a front wall 52, having a sloping front surface 53 and a rearwardIy projecting bottom flange 54, and a pair of longitudinally disposed, spaced webs 55 and 56. As shown in FIGURES 2 and 3, the bottom edge of rear wall 51 is adapted to be seated on a rigid cross beam member 18 and the bottom surface of flange 54 is adapted to be seated on the top wall of a movable grate 40a or 41a. As best seen in FIGURE 6, each of the rigid cross beam members 18 is provided with a pair of flanges 57 and 58, defining a transversely disposed slot therein, in which the rear end walls 51 of the stationary grates 39a are seated. The, flange 58 is provided with slots along the length thereof to accommodate the rearmost portions of the flanges 55 and 56 of the stationary grates.

Each movable grate 40a consists of a top wall 59, a rear end wall 60 having a sloped portion 61, a front end wall 62 having a sloped front surface 63 and a rearwardly projecting bottom flange 64, and a pair of longitudinally disposed, spaced webs 65 and 66. When the grate is installed in the stoker, as illustrated in FIGURE 2, the rear end wall 60 is adapted to be seated on a rigid cross beam member '24, and the bottom surface of flange 64 is adapted to be seated on-the top wall 50 of a stationary grate 39a. Each of the rigid cross beam members 24 is provided with a pair of transversely disposed flanges 67 and 68, defining a transverse channel or slot in which the rear end walls 60 of the movable grates 48 are seated. The flange 68 also is interrupted with slots for receiving the rearward portions of the flanges 65 and 66 when the rear end wall 60 of each stationary grate 40 is seated in the channe between the flanges 67 and 68.

The movable grates 41a are constructed similarly to the movable grates 40a. Each grate 41a also is mounted in the stoker with the rear end wall thereof seated on a movable cross beam member 34 and a forwardly disposed bottom flange seated on the top wall 50 of a stationary grate 39a. Each of the movable cross beam members 34 also is provided with a pair of transversely disposed flanges 69 and 70, forming a channel or slot for receiving the rear end wall of the movable grates 41a. In addition, the flange 70 is provided with suitable slots for accommodating the webs on the grates 41a when the grates are seated on the cross beam member 34.

Referring to FIGURE 6, illustrating the stationary grates 39a mounted on rigid cross beam member 18, movable grate 40a mounted on movable cross beam member 24 and movable grates 41a, mounted on movable cross beam member 34, in assembled relation, it will be noted that the movable grates 40a and 4101 are disposed above and below the stationary grates 39a and are adapted to reciprocate in substantially parallel planes, in opposite directions simultaneously, to form the steps along the length of the stoker, as previously described. The mounting of the rear end walls of the grates in the transverse slots on the rigid and movable cross beam members are effective in providing a suitable operative connection therebetween, thus permitting the reciprocating motion of the movable cross beam members to be transmitted to the movable grates. The seating arrangement of the stationary and movable grates on the cross beam members also .prevents any longitudinal or lateral displacement of the grates. It further will be appreciated that individual defective grates can be replaced with little effort and without disassembling any major portion of the stoker.

Referring to FIGURES 8 and 9, there is illustrated modified stationary and movable grates 39b and 40b. The grate 3% consists of a top wall 71 having a plurality of longitudinally disposed ribs 72 forming longitudinal guideways 73, a rear end wall 74, a front end wall 75 having a sloped front surface 76 and a rearwardly projecting bottom flange 77 provided with a plurality of longitudinally disposed guideways 78, and reinforcing webs 79 and 80. With the exception of the longitudinal ribs 72 formed on the top wall 71 and the longitudinal slots or guideways 78 formed in the bottom flange 77, the grates 3911 are identical to the previously described grates 39a and are mounted in the stoker illustrated in FIGURE 2 in the same manner as the grates 39a. Each of the movable grates 40a consists of 'a top wall member 81, having a plurality of longitudinally disposed ribs 82 forming longitudinal slots or guideways 83, a rear end wall. 84, a front end wall 85 having a sloped front surface 86 and a rearwardly projecting bottom flange 87 provided with a plurality of longitudinally disposed slots or guideways 88, and longitudinally disposed, spaced reinforcing webs 89 and 90. The movable grate 40b is similar in construction to the movable grates 40a and 41a, with the exception of the longitudinal ribs 82 on the top wall 81 andthe longitudinal slots or guideways 88 formed in the bottom flange 87 thereof. Also, the grates 40b are adapted to be mounted in the stoker illustrated in FIGURE 2 in a manner similar to that of movable grates 40a and 41a.

When the grates 39b and 40b are assembled in the stoker illustrated in FIGURE 2, the guideways 88 in grate 40b will receive the longitudinal ribs 73 of the grate 3% when the front end of the grate 40b is seated on the top wall 71 of grate 3%, as illustrated in FIGURES 8 and 9. In assembled relation in the stoker, the ribs 82 of movable grates 4011 will be received in the slots or guideways 78 of adjacent stationary grates 39b. It will be appreciated that the interrelationships between the grates 39b and 40b will accurately guide the movable grates 40b as they are reciprocated relative to the stationary grates 39b, and furthermore, will prevent refuse from being drawn between stationary and movable grates, which would tend to impair the operation or cause damage to the stoker.

Referring to FIGURES 2 and 3, the stoker is operated by first charging refuse into the incinerator 91, whereby the refuse is guided along a charging chute 92 onto the upper end of the stoker grates. As soon as an initial load of refuse has been deposited on the upper end of the grates, the drive mechanisms 42 and 43 are actuated to move the carriage assembly 19 rearwardly and the carriage assembly 29 forwardly, as illustrated by the arrows in FIGURE 3. As such action takes place, the movable grates 40 will be retracted and moved rearwardly while the movable grates 41 will be extended and moved forwardly to form a new series of steps along the length of the stoker. The new series of steps formed, as illustrated in FIGURE 3, are longitudinally displaced relative to the series of steps formed when the movable grates 40 are extended and the movable grates 41 are retracted, as illustrated in FIGURE 2.

As the carriage assemblies 19 and 29 move in opposite directions from their positions, as illustrated in FIGURE 2 to their positions as illustrated in FIGURE 3, and a new series of steps is formed along the length of the stoker, refuse deposited on the stoker will be caused to tumble along the length of the stoker from the charging end to the discharge end thereof. The tumbling action is caused by a combination of the stoking action of the grates and the force of gravity. The tumbling of the refuse on the stoker will result in greater areas of the mass of refuse being exposed for burning. Interwoven masses of refuse will be caused to separate, thus exposing additional areas for burning.

The reciprocating motion of the carriage assemblies 19 and 29 can be either continuous or intermittent, as desired. In addition, the speed of the moving carriage assemblies can be regulated by operation of the control means included in the fluid supply circuits for the drive mechanisms 42 and 43. Other types of drive means also can be employed for reciprocating the carriage assemblies. For instance, gear and rack type mechanisms can be employed, in lieu of the fluid cylinder assemblies, for reciprocating the carriage assemblies.

The operating components of the stoker construction are adapted to be readily assembled and disassembled. In assembling the stoker, the carriage assembly 29 is first lowered between the side walls 13 and 14 of the support frame and seated on the support brackets 36. The rearward end of the carriage assembly 29 is connected to the drive assembly 43. Next, the carriage assembly 19 is lowered between the side walls 13 and 14 and seated on the support brackets 26. The rear end of the carriage assembly 19 is connected to the drive assembly 42. With the carriage assemblies thus positioned in place, the stationary and movable grates are installed.

The installation of the grates begins at the lower end of the stoker by installing a first set of stationary grates 39 which are mounted in the stoker, bridging the first rigid cross beam member 18 and a transverse ledge member 93 mounted on the upper end of the front wall 11. After the first set of stationary grates 39 is set in place, the first set of movable grates 40 is installed so that the rearward end of each grate is supported on the movable cross beam member 24 and the forward end thereof is seated on a stationary grate 39. A second set of stationary grates 39 are then installed, whereby each stationary grate 39 is mounted at its rear end on the second rigid cross beam member 18 and is mounted at its forward end on a movable grate 40. Next, the first set of movable grates 41 is installed, so that the rear end of each grate is supported on the first movable cross beam member 34 and the front end thereof is seated on a stationary grate 39 of the second set of stationary grates. The remaining stationary and movable grates are installed in a similar arrangement until the assembly is Completed. To disassemble the stoker, the aforementioned procedure essentially is reversed. It will be appreciated, however, that any individual defective grate can readily be removed and replaced simply by lifting the grate next above the defective grate, removing the defective grate by slightly lifting the rearward end thereof and sliding it forwardly, inserting a new grate so that the rear end wall thereof is supported on a cross beam member and the front end thereof is supported on the adjacent grate disposed therebelow and lowering the next above grate. In installations where the nature of the refuse would have a tendency to be drawn between the grates, the modified forms of grates illustrated in FIGURES 8 and 9 can be used.

From the foregoing detailed description it will be evident that there are a number of changes, adaptations and modifications of the present invention which come within the province of those skilled in the art. However, it is intended that all such variations not departing from the spirit of the invention be considered as within the scope thereof as limited solely by the appended claims.

I claim:

1. A stoker construction comprising a support means, a plurality of stationary grates mounted on said support means, spaced along an inclined plane, a first plurality of movable grates, spaced along said inclined plane and disposed between a first set of alternate spaces between said stationary grates, a second plurality of movable grates, spaced along said inclined plane and disposed between a second set of alternate spaces between said stationary grates, wherein movable grates are disposed above and below each stationary grate in slidable engagement therewith, means for reciprocating said movable grates, and successive movable and stationary grates having cooperative guide means.

2. A stoker construction according to claim 1, wherein said cooperative guide means comprise registrable longitudinal slots and ribs.

3. A stoker construction comprising a support frame, a plurality of stationary grates mounted on said frame, spaced along an inclined plane, a first carriage mounted on said frame, a first plurality of movable grates mounted on said first carriage for movement therewith and spaced along said inclined plane, said first set of grates being disposed in a first set of alternate spaces in said plurality of stationary grates and movable in planes intersecting said inclined plane of said stationary grates, a second carriage mounted on said frame, a second plurality of movable grates mounted on said second carriage for movement therewith and spaced along said inclined plane, said second plurality of movable grates being disposed in a second set of alternate spaces in said plurality of stationary grates and movable in planes intersecting said inclined plane of said stationary grates wherein movable grates are disposed above and below each of said stationary grates in slidable engagement therewith, means operatively connected to said carriages for reciprocating said carriages and, correspondingly, said movable grates along their lines of movement intersecting said inclined plane of said stationary grates, and successive movable and stationary grates having cooperative guide means.

4. A stoker construction according to claim 3, wherein said cooperative guide means comprise registrable longitudinal slots and ribs.

5. A stoker construction comprising a support frame, a plurality of transversely extending, longitudinally spaced beams rigidly mounted on said frame, lying in an inclined plane, a set of stationary grates mounted on each of said rigidly mounted beams, a first carriage mounted on said support frame, said first carriage having a first plurality of transversely disposed, longitudinally spaced beams mounted thereon and disposed below said plurality of rigidly mounted beams, a first set of movable grates mounted on each of said movable beams and movable therewith, said first sets of movable grates being disposed in a first set of alternate spaces in said sets of stationary grates, a second carriage mounted on said support frame, said second carriage having a second plurality of transversely disposed, longitudinally spaced beams mounted thereon and disposed below said plurality of rigidly mounted beams, a second set of movable grates mounted on each of said second movable beams and movable therewith, said second sets of movable grates being disposed in a second set of alternate spaces in said sets of stationary grates wherein sets of movable grates are disposed above and below each set of stationary grates in slidable engagement therewith, each of said movable carriages having surfaces engageable with camming surfaces on said support frame whereby upon predetermined relative reciprocating movement therebetween each set of movable grates mounted thereon will be caused to reciprocate along a predetermined line of travel between successive sets of stationary grates, means operatively References Cited UNITED STATES PATENTS 3,126,846 3/1964 Wagner 110-38 FOREIGN PATENTS 461,849 6/ 1928 Germany.

JAMES W. WESTHAVER, Primary Examiner.

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