US2486570A - Spreader stoker fuel feeding mechanism - Google Patents

Description

Nv. l, 1949. D. J. MossHART ETAL 2,486,570

SPREADER STOKER FUEL FEEDING MECHANISM Filed Oct. 18, 1946 28 Z wlTNEssEs: Z a INVENTOR s M Down/ D :JI Moss/HART. /E 2 :fof/N .5. HsRw/CK.

ATTORNEY Patented Nov. l, 1:949

SPREADER STOKER FUEL FEEDING MECHANISM Donald J. Mosshart, Ardmore, and John S. Herwick, Philadelphia, Pa., assignors to Westinghouse Electric Corporation, East Pittsburgh, Pa., a corporation of Pennsylvania Application October 18, 1946, Serial No. 704,160

4 Claims. (Cl. 110-115) This invention relates to stokers, more particularly to those of the spreader or sprinkler type, and has for an object to provide improved apparatus of this character.

In spreader stoker apparatus, where the fuel is fed rearwardly over the discharge end of a spill plate, for gravitational feed to impeller mechanism, the fuel so fed frequently falls in large masses or chunks from the rear end of the spill plate to the impeller therebelow. This condition is aggravated when the fuel is wet, and even With dry fuel the fuel falls from the spill plate in sufficiently uneven quantities and at such uneven rates that the feeding thereof by the impeller to the interior of the furnace is generally erratic. Where the fuel falls uniformly from the spill plate to the impeller, the impact between the impeller and the fuel is substantially uniform, but where the fuel falls in irregular or small masses there is a cushioning effect resulting in non-uniform distribution of the fuel by the impeller.

In lcopending application, Serial No. 504,395, for Spreader stoker mechanism, led September 30, 1943, now Patent No. 2,423,110 granted July 1, 1947, and assigned to the assignee of the present invention, there is disclosed apparatus for overcoming this difficulty and which apparatus involves a corrugated plate extending transversely of the spreader mechanism, with the corrugations extending vertically, the plate being so disposed that reciprocation thereof causes the ribs of the corrugations to rub upon the fuel as the latter approaches the discharge end of the spill plate, thereby reducing the size of the mass of fuel by a grating or shredding action, the grated or shredded particles of fuel falling uniformly to the impeller therebelow.

It has been found that, under certain conditions, this equalizing plate, which is mounted for pivotal movement about a horizontal axis so that the lower edge thereof may be forced away from the spill plate rear discharge edge by the fuel pushing thereagainst, is sometimes pushed away from the spill plate by a large lump of coal or foreign matter which opens a gap between the equalizer plate and rear discharge edge through which an excessive quantity of fuel may cascade to the impeller therebelow. Also, where a plurality of rams or equivalent structures are operating out of phase to push fuel rearwardly over the spill plate and against the equalizing plate, the action of the rearmost ram may swing the equalizing plate away from the rear discharge edge` of the spill plate thereby opening an excessive gap all along the spill plate rear edge, resulting in an undesirable cascading of fuel to the impeller.

The present invention eliminates this difficulty by providing an equalizing plate structure in which a plurality of plate elements are mounted on a horizontal axis for independent pivotal movement thereablout so that any one plate element can move away from the rear spill plate discharge edge and the remaining plate sections remain` adjacent thereto. Preferably, the plate elements correspond in transverse location to the fuel-pushing rams, paddle wheels or other mechanisms for feeding the fuel from the hopper to the rear spill plate discharge edge.

Accordingly, another object )of the invention is to provide, in spreader stoker apparatus, means for effecting a uniform feed of fuel to the impelling structure.

These and other objects are effected by the invention as will be apparent from the following description and claims taken in connection with the accompanying drawing, forminga part of this application, in which:

Fig. 1 is a longitudinal sectional view through spreader stoker apparatus embodying the principles of the present invention; and,

Fig. 2 is a transverse sectional view taken along the line II-II of Fig. 1, looking in the direction indicated by the arrows. Y

Referring now to thek `drawing more in detail, the reference character I0 indicates, in its entirety, spreader mechanism for feeding fuel rearwardly through the opening I I inthe front Wall I2 of the furnace I3, for distribution thereof on the gratestructure I4, at the bottom of the furnace. Fuel is fed by gravity fromthe hopper I6 to the bottom plate I'I of the ram box structure I8 where a pair of rams I9, disposed in side-byside relation, push the fuel rearwardly. The rams I9 may be reciprocated by any suitable mechanism (not shown) and which derives its power rfrom the engine 20 (Fig. l). Preferably, the ram-reciprocating mechanism is so arranged that the two rams I9 operate out -of phase by approximately l degrees with the result that while one ram is moving rearward the other ram is moving forward.

Reciprocation of the rams I9 pushes the fuel from the hopper I 6 rearwardly over the spill plate 23 for gravitational discharge over the rear edge 2'4 thereof to the rotary impeller 26 positioned therebelow. The impeller 26 is mounted on a horizontal shaft 21 and carries a plurality of blades 28 adapted to strike the fuel falling from 3 the rear discharge edge of the spill plate and to project it rearwardly through the furnace wall opening H to the grate structure I4.

In order to vary the trajectories of the fuel leaving the rotary impeller 26, the spill plate preferably is arranged for longitudinal reciprocation, such movement being imparted thereto by rods 29, 4links 30 and cranks 3|, the latter being xed on the shaft 32 Which may be oscillated in any desired manner, one such means being fully disclosed in copending application, Serial No. 549,848, filed August 17, 1944 and assigned to the assignee of the present application.

The equalizing mechanism, indicated in its entirety by the reference character 35, for preventing lcascading of large quantities of fuel from the rear discharge edge 24 of the spill plate, includes a pair of plate members 36 pivotally mounted at their upper edges on a horizontal transversely-extending shaft 31 with the lower edges 36 of the plates disposed close to the spill plate rear discharge edge 24.` The hollow beads 39 at the upper edge of the plates 36, through which the shaft 31 passes, project laterally beyond the side wal-1s 4| of the spreader casing, as at 42, with arms 43 rigidly secured to the projecting portions 42.

A pair of wires 44 are connected at one end, through turn-buckle structures 45, with the free ends of the arms 43, these wires 44 passing around a pair of pulleys 46 carried by brackets 41 secured to the angle iron 43 on the furnace front wall l2. The other ends of the wires 44 are secured to opposite ends of the tension spring 49 which results in forces being applied to the two plate sections 36 which forces urge the plate lower edges 38 into contact with the rear discharge edge 24 of the spill plate 23.

It will be apparent that, if either plate section 36 is swung rearwardly due to the pushing action thereagainst of fuel moved rearwardly by the ram aligned therewith, the corresponding end of the wire 44 will be pulled forwardly through the turn-buckle mechanism 45, thereby increasing the tension in the spring 43 which in turn will increase the force upon the other plate section 36 urging it even more` firmly into engagement with the rear discharge edge 24 of the spill plate, thereby preventing accidental cascading of excessive quantities of fuel past the other plate section 36 upon rearward movement of the first plate section.

As in the construction disclosed in the rstmentioned copending application, means are provided for transversely reciprocating the equalizing plate structure to impart a shredding or grating action to the fuel pushed thereagainst by the rams. In the present construction, this reciprocating mechanism comprises extensions I on the horizontal shaft 31 which supports the equalizer plate sections 36. These extensions 5l are supported by pairs of vertically-spaced rollers `52 carried by brackets 53 and 54. Limited reciprocating movement of the shaft 31 is eected by lever 55 and links 56 and 51, the link 56 connecting the upper end of the lever 55 to one end of the shaft 31 and link 5lconnecting the lower end of the lever 55 to an eccentric 58 .carried by the output shaft of a gear box 59 whose input shaft pulley 6| is driven by the belt 62, through the pulley 63 on the rotary impeller shaft 21, which may be driven from any suitable source (not shown).

To avoid any possibility of breakage of thereciprocating mechanism due to jamming of the y spill plate sections 36, the pivot 64 of the lever is carried by a support 65 which floats between a pair of opposed coil springs 66, as shown at the left of Fig. 2.

Preferably, vertical ribs 61 are provided on the forward face of the equalizer plate sections 36 to increase the grating action of the reciprocating plate sections on the fuel pushed thereagainst by the rams I9.

While the invention has been shown in but one form, it will be obvious to those skilled in the art that it is not so limited, but is susceptible of various changes and modifications without departing from the spirit thereof.

What is claimed is:

l. Spreader stoker mechanism comprising an impeller; fuel-supporting structure having a rear discharge edge positioned for gravity feed of fuel therefrom to said impeller; means for feeding fuel rearwardly along the fuel-supporting structure to the rear discharge edge thereof; a pair of plates disposed 'adjacent the fuel-supporting structure rear discharge edge and adapted for pivotal movement relative to a horizontal axis parallel to said rear discharge edge; and means iasing said plates towards engagement with said rear discharge edge, said last-mentioned means including mechanism Ifor increasing the biasing force on either of said plates when the other plate is moved against its biasing force.

2. Spreader Stoker mechanism comprising a fuel impeller; structure providing a fuel-supporting surface having a rear discharge edge positioned for gravitational feed of fuel therefrom to said impeller; means for feeding fuel rearwardly along said fuel-supporting surface to said rear discharge edge; wall structure including a pair of vertically-extending sections mounted for independent pivotal movement about an axis above and approximately parallel to said rear discharge edge; and an energy-storing device connected with both of said wall sections for continuously exerting on said sections forces tending to pivot the latter into positions retarding gravitational discharge of fuel from the fuel-supporting surface rear discharge edge, movement of either section away from discharge-retarding position effecting increase in the force exerted on the other section by the energy-storing device.

3. Structure as specified in claim 2, wherein the energy-storing deviceincludes a tensioned spring with @opposite ends connected to the two wall sections whereby movement of either of the wall sections away from fuel-discharge-retarding position effects increasein the tension of the spring with consequent increase in the force exerted fon the other section by said spring.

4. Spreader Stoker mechanism comprising a fuel impeller; structure providing a fuel-supporting surface having a rear discharge edge positioned for gravitational feed of fuel therefrom to said impeller; a pair of first members for feeding fuel rearwardly along said fuel-supporting `surface in a pair of parallel paths with one of said rst members lagging the other in fuelfeeding action; a pair of barrier members each mounted for movement independent of the other toward and away from said rear discharge edge within predeterminedlimits in response to pushing action of the respective streams of fuel thereagainst, said barrier members normally being positioned in close proximity to said rear discharge edge and across the parallel paths of fuel feed, and means responsive to movement of either of the-barrier members away from the fuel-support- DONALD J. MOSSHART. JOHN S. HERWICK.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,163,825 Bros June 27, 1939 2,423,110 Mosshaxt July 1, 1947

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