US2165098A - Stoker - Google Patents

Description

J. R. GRAVES STOKER zal Patented July 4, 1939 UNITED sTA'rEs PATENT oFFIcE s'roKEa of Delaware Application August 5,

13 Claims.

This invention rel'ates to stokers of the type employing a conveyor screw for delivering coal to a distributing device positioned at an-openng in a furnace wall.

It is the prncipal object of this invention to prolong the life of vital stoker parts upon which coal lies in certain dormant zones during passage of the bulk of the coal to the distributing device, and in which dormant zones the corrosive action of the coal causes such vital stoker parts to deteriorate rapidly.

More specifically, the invention contemplates the provision of guard plates which are in a novel I relation With the stoker conduit and vital parts 15 of the distributing device whereby the objectionable dormant zones of coal and the attendant dificulties are eliminated.

As a further object thereof, the invention |consists in the provision of guard plates which constitute forward extensions of a cylindrical conduit at the juncture thereof with a conduit discharge mouth which is of somewhat angular configuration in transverse cross section.

Other' objects are to provide the novel guard plates, their mode of attachment to the distributor head and their novel relation with vital stoker parts.

In the drawing:

Fig; 1 is a Vertical longitudinal section through the delivery end of a stoker and the adjacent portion of a furnace showing the invention as applied thereto;

Figs. 2, 3 and 4 are views in section taken along the lines 2 2, 3-3, and 4-4, respectively, of Fig. 1; and A Fig. 5 is a fragmentary view similar to Fig. 4, illustrating a modification.

Referring `to the drawing, there is shown at a portion of an upstanding wall of a boiler firebox 8 having a firing opening 1| therein to which fuel is advanced by the conveyor screw 12. The screw 12 is housed within the inclined stoker conduit 13 which opens endwise into the firing opening I I. At its forward end the stoker conduit 13 is provided With a mouth portion 14 extending across the lower portionvof the firing opening. Any preferred construction may be employed to attach the conduit 13 to the wall 111 for the purpose of maintaining the conduit mouth portion 14 in communication with the firing opening 1 I. In transverse cross section, rearward of its mouth portion, the interior of the conduit 13 is circular in cross section. Immediately forward of its circular portion, the conduit changes abruptly to an inverted U-section, and in its for- 1936, Serial No. 94,357

ward extent changes gradually to the rectangular cross section, as illustrated in Figures 4, 3 and 2. a

Forward of its circular portion, the bottom of the stoker conduit 13 is open between the side walls 15, 16. A distributor member or head 1'1 having a flat upper surface is detachably disposed, as will presently appear, in the opening 9 at the upper forward end of the stoker conduit 13 to form a floor portion for the delivery end of the conduit. It will be observed that 'the distributor head 11 extends beyond the conduit mouth portion into the firing opening 11 to a point intermediate the inner 'and outer surfaces of the firebox wall 10. At its forward end the distributor head 1'1 detachably supports the table 18. a

A plurality of vertically spaced horizontal rows of jet openings 19 extend across the upright face 20 of the distributor head 11. These jet openings communicate with one or more chambers 2| formed within the distributor head 1'1 beneath the upper surface thereof. Steam or any other suitable pressure fiuid is supplied to the chambers 21 through intake openings such as 22. Fuel advanced by the conveyor screw 12 is moved over the upper surface of the distributor member 11 into the zone of action of the pressure fluid blasts discharging from the jet openings 19, which blasts serve to project the fuel across the table 18 for distribution over the firebed in the firebox. Adjustable defiector vanes 23,24 constitute forward continuations of the conduit side walls 15, 16, respectively, and they are mounted upon pivot pins such as 25 whereby -each may be set at any desired angle with respect to the upright face 20 of the distributor head 11 for the purpose of controlling the delivery of fuel to the distributing device.

The distributor head 11 is seated upon ledges 26 which extend inwardly from the side walls 15, 16 and ledges 26a extending forward of the' transversely disposed boss 2'1 depending from the lower forward edge of the tubular portion of the stoker conduit, said side walls and boss 21 defining the opening 9 in the bottom of the stoker conduit 13. Adjacent the boss 21, each side wall 15, 16 has threaded thereinto a screw 28, the tapered inner portion 29 of which is arranged' to press firmly against the upper surface of the distributor head 1'1 and also against a lug such as 30 whereby upward and fore and aft movement of the distributor head 1'1 is restrained during normal operation of the stoker. 'Whenever itis desired to remove the distributor head 1'1 from its position over the opening 9, the screws 28are threaded outwardly a distance to clear the lugs 30,, Whereupon the mechanic may remove the head by drawing the same forwardly and upwardly into the firebox a slightdistance. stood that the firedoor 3| is thrown open during thisl operation.

Due to the fact that the change in cross sectional configuration of the stoker conduit from its circular portion to its inverted U-shaped portion is abrupt, a certain amount 'of coal, heretofore, in passing from the circular section into the inverted U-shaped section, would remain dormant along the side walls |5, |6 of the stoker conduit |3 and also along the lateral sides of the upper surfacev 32 of the distributor head H. This dormant zone of coal extends a substantial disancelorward of the circular section of the conuit It has been experienced in actual service of the described stoker device, prior to this invention, that the coal lying more or. less dormant along the lateral sides of the distributor head |'l will `cause corrosion of its surface 32. ,Furthermore, since the coal along the corroded portions of' the surface 32 is not subject to the direct impelling action of the'conveyor screw |2, whatever forward movement of the coal in these zones occurs is accompanied by a sliding action of the coal lumps along the corroded portions of the surface. The coal sliding, or'being pushed, slowlyalong the aifected portions of the surface'32 is under greater pressure at these zones than at other portions of the stoker conduit |3; consequently, greater friction results so -that within a comparatively short time the surface 32 wears 'through to van extent that,.the cored chambers -an inclined rearward surface portion 40 and a forward surface portion 4| at a lesser angleof inclination with respect tothe horizontal than surface portion 40. On the outer-portions of the forward surface por-tion 4| areformed ridges 42 and 43 constituting prolongations -of the rear- 'ward surface. portion 40, the ridges'42 and 43 having plane upper surfaces in the plane of the rearward surface portion 40. Each guard plate 33 has a plane under surface providing surface contact between the aforesaid under'surface of the guard-platesf33 on the one hand' and the v rearward surface portion 40 and' the surfaces of the ridges 42 and 43 of the distributor. head |1 on the otherhand. Each guard plate 33 has an arcuate-shaped wall 34, the radius of vcurvature of which approximates that of the`circular portion of the stoker conduit. At its rearmost porltion, the upper edge 35 of leach arcuate 'wall' 34 extends to a maximum above the upper surface of the surface ``'32, and is inclined toward its lower edge- The .upper edge 35 of each arcuate wall 3-4 throughoutthe' length thereof contacts the respective side walls |5, IG of the stoker conduit.-

The guard plate may be constructed, if desired, with the arcuate walls 34 thereof joined at their It will be under-v ,Thisinner portions, or, as shown in Fig. 5, these arcuate walls 34a may be made integral with the upper surface 32a of the distributor head I'Ia. However, it is preferred that ythe arcuate walls 34 at the sides of the stoker conduit |3 be mader 5 v separable from`each other in order to facilitate their application tol` the distributor head l'l.

As illustrated in Figures 3 and v4=, each guard plate 33 is provided at its under side with an enlarged portion such as 36 into each of which a fscrew 31 is threaded. Each screw 31 passes through the upper surface 32 of the distributor head |1 and detachably secures each guard plate to the distributor head ll. Before securing the guard plates 33 to the distributor head l'l, the former are'each fitted into the stoker conduit |3 and their Vpositions carefully scribed .upon the 'upper surface 32.

Whereupon, the distributor head |.1 is removed form the stoker conduit in the heretofore described manne'r, the guard plates 33 placed upon their scribedroutlines and holes drilled in the distributor' head I'l and tapped in the guard plates 33 whereby the screws 31 are passed through the head" and threaded into the guard plates for ,securing they latter to the former. V

From the foregoing, it will be apparent that the herein describedi construction prolongs the life of the distributor head I'l by insuring that coal is moved constantly therealong because the zones where coal may lie dormant have been effectively eliminated..

'I claim the following as new and useful:

-1. A pressure fluid distributor head for ai stoker comprising a fiat upper surfacenmeans providing ya plurality lof pressure fiuid chambers `underneath said upper surface; a wall depending from one end of saidupper surface and having a plurality 'of pressurefluid discharge orifices therein communicating with said chambers,'and an arcuate wall at each side of said upper surface extending upwardly therefrom, said arcuate -walls extending forwardly from the end of said upper surface remote from the said depending wall and being spaced inwardly from the side edges o f said upper surface at the last named end thereof and diverging to the side edges of saidupper -surface at they extend forwardly.

2. A pressure fluid distributor head' for a Vstoker' comprising a flat' upper surface, means providing a plurality of pressure fluid chambers under-neath said upp'er surface, a wall depending from one end of said upper surface and having a plurality of pressure'fiuid discharge orifices therein communicating with said chambers,

. and an arcuate wall at each side of said upper surface formed integrally therewith and extending upwardly therefrom, said arcuate walls extending forwardly from the end of said upper surface remote from said depending' wall and being spaced inwardly from the side edges of said top surface at the last named end thereof and diverging to the side edges of said .upper surface as they extend forwardly.

, 3. A guard plate for a stokerdistributor head comprising an' arcuate wall having the same `radius of curvature throughout its length, the

bottom of said arcuate wall throughout the length -thereof having a plane surface, said arcuate wall at one end of said guard plate being at a maximum 'distance above the aforesaid plane of said bottom surface and thence sloping to- Ward said bottom surface, said bottom surface being provided with threaded .openings.

. 4. In combination with a stoker conduit having a tubular portion provided with a bottom wall. the inner surface thereof bing arcuate in transverse cross section, and a delivery portion immediately forward of said tubular portion, said delivery portion including upright side walls, a distributor head detachably disposed in said delivery portion between the lower ends of said side walls and immediately forward of the tubular portion of said conduit, said distributor head including a fiat upper surface constituting, a support for coal passing through said conduit, and an upstanding wall located within and at each side o-f said'delivery portion immediately forward of the tubular portion of the stoker conduit, said upstanding walls being disposed on the upper surface of said distributor head spaced inwardly at their lower edges from the side walls of said delivery portion and extending upwardly to said side walls. v v

5. In combination with a stoker conduit having a tubular portion provided with a bottom wall, the inner surface thereof being arcuate in transverse cross section, and a delivery portion immediately forward of said tubular portion, said de-I livery portion including upright side walls, a distributor head detachably disposed in said delivery portion between the lower ends of said side walls and immediately forward of the tubular portion of said conduit, said distributor head including a fiat upper surface constituting a support for coal passing through said conduit, and an upstanding arcuate wall located Within and at each side of said delivery portion immediately forward of the tubular portion of the stoker conduit, said arcuate walls being disposed on the upper surface of said distributor head spaced inwardly at their lower edges from the side walls of said delivery portion and curving upwardly and outwardly to said side walls.

6. In combination with a stoker conduit having a tubular portion provided with a bottom wall, the inner surface thereof being arcuate in transverse cross section, and a delivery portion immediately forward of said tubular portion, said delivery portion including upright side walls, a distributor head detachablydisposed in said delivery portion between the lower ends of said side walls and immediately forward of the tubular portion of said conduit. said distributor head including a fiat upper surface constituting a support for coal passing through said conduit, and a separable upstanding wall located within yand at each side of said delivery portion immediately forward of the tubular portion of the stoker conduit, said f upstanding walls being detachably secured on the upper surface of said distributor head spaced inwardly at their lower edges from` the side walls of said delivery portion and extending upwardly to said side walls.

7. In combination with a stoker conduit having a tubular portion provided With a bottom wall, the inner surface thereof being arcuate in transverse cross section, and a delivery portion immediately forward of said tubular portion, said delivery portion including upright side walls, a

distributor head detachably disposed in said delivery portion between the lower ends of said side Walls and immediately forward of the tubular portion of said conduit said distributor head including a fiat upper surface constituting a support for coal passing through said conduit; and a separable arcuate upstanding wall located within and at each side of said delivery portion immediately forward of the tubular portion of the stoker conduit, said arcuate walls being detachably secured on the upper surface of said distributor head spaced inwardly atfitheir lower edges from the side walls of said delivery portion and curving upwardly and outwardly to said side walls.

8. In combination with a stoker conduit having a tubular portion provided with a bottom wall, the inner surface thereof being arcuate in transverse cross section, and a delivery portion immediately forward of said tubular portion, said delivery portion including upright side walls, a distributor head detachably disposed in said delivery portion 'between the lower ends of said side walls and immediately forward of the tubular portion of said conduit, said distributor head including a fiat upper surface constituting a support for coal passing through said conduit, and an arcuate wall located within and at each side of said ldelivery portion immediately forward. of the tubular portion of the stoker conduit, said arcuate walls being integrally fcrmed with the upper surface of said-distributor head spaced inwardly at their lower edges from the side .walls of said delivery portion and curving upwardly and outwardly to said side walls.

9. In combination with al stoker conduit having a tubular portion provided with a bottom wall, the inner surface thereof being arcuate in transverse cross section, and a delivery portion immediately forward of said tubular portion, said delivery portion including, upright side walls, ledges extending laterally inward of the lower ends of said upright side walls and forward of the lower forward end of said tubular portion, a distributor head seated on said ledges between the lower ends of said side walls and immediately forward of the lower forward end of said tubular portion, said distributor head including a fiat upper surface constituting a support for coal passing through said conduit, and an upstanding wall located within and at each side of said delivery portion immediately forward of the tubular portion of the stoker conduit, said upstanding walls being disposed on the upper surface of said distributor head spaced inwardly at their lower edges from the side Walls of said delivery portion and extending upwardly to said side walls.

10. In combination with a stoker conduit having a tubular portion provided with a bottom wall, the inner surface thereof being arcuate in transverse cross section, and a delivery portion immediatelyforward of said tubular portion, said delivery portion including upright side walls, ledges extending laterally inward of the lower ends of said upright side walls and forward of the lower forward end of said tubular portion, a distributor head seated on said ledges between the lower ends of said side lwalls and immediately forward of the lower forward end of said tubular portion, said. distributor head including a fiat upper surface constituting a support for coal passing through said conduit, and an upstanding arcuate wall located vvithin and at each side of said delivery portion immediately forward of the tubular portion of the stoker conduit, said arcuate walls being disposed on the upper surface of said distributor headspaced inwardly at their lower edges from the side walls of said delivery portion and curving upwardly and outwardly to said side Walls.

11. In combination With a stoker conduit having a tubular portion provided with a bottom wall, the inner surface thereof being arcuate in tranverse cross section, and a delivery portion immediately forward of said tubular portion, said delivery portion including upright side walls; 'w

ledges 'extending laterally inward of the lower ends of said upright side walls and forward of the lower forward end of said tubular portion, a distributor head seated on said ledges between the lower ends of said side walls and immediately forward of the lower forward end of said tubular 'portion,- said distributor head including a flat upper surface constituting a support for coal passing through said conduit, and a separable upstandingvwall located within and at each side of said delivery portion immediately for- Ward of the tubular portion of the stoker conduit, said upstanding walls being detachably sec'ured on the upper surface of said distributor head spaced inwardly at their lower edges from the side walls of said delivery portion and extending upwardly to said side walls.

12. In combination with a stoker conduit having a tubular portion provided with a bottom wall, the inner surface vthereof being arcuate in transverse cross section, and a delivery portion immediately forward of said tubular portion, said delivery portion including upright side walls, ledges extending laterally inward of the lower ends of said upright side walls and forward of the lower forward end of said tubular portion, a distributor head seated on said ledges between the lower ends of said side walls and immediately forward of the lower forward end of said tubular portion, said distributor head including a fiat upper surface constituting a support for coal passing through said conduit, and a separable 4 aieaoee arcuate upstanding wall located within and at each side of said delivery portion immediately forward of the tubular portion of the 'stoker conduit, said arcuate walls beingdetachablysecured on the upper surface of said distributor v head spaced inwardly at their lwer edges from the side walls of said delivery portion and curving upwardly and outwardly to said side walls.

13. In combination with a stoker conduit having a tubular portion' provided' with a bottom wall, the inner surface thereofl being arcuate in transverse cross section, and a delivery portion immediately forward of said tubular portion, said delivery portion including' upright side walls, ledges extending laterally inward of 'the lower ends of said upright side walls and forward of the lower forward 1 end of said tubular portion, a distributor head seated on said ledges between the lower ends of said side walls and immediately forward of the lower forward end of said tubular portion, said distributor head including a fla-t upper surface constituting a support for coal passing through said conduit, and an arcuate wall located within and ``at each side of said delivery portion immediately forward of the tubular portion of the stoker conduit, said arcuate walls beingintegrally formed with the upper surface of said. distributor head spaced inwardly at their lower edges from the side walls of said delivery portion and curving upwardly'and outwardly to said side walls.

JOHN R.. GRAVES.

Images