US1540546A - Underfeed mechanical stoker - Google Patents

Description

June 2, 1925.

W. J. H. DIPLOCK UNDERFEED MECHANICAL STOKER Filed May 5, 1924 Patented June 2, 1925.

"UNITED STATES 7 WILLIAM JOHN HUBER! DI'QPLOCK, or CRQYDON, ENGLAND; ASSIGNOR- or QNET H'ALE To ERITHS ENGINEERING BRITISH COMPANY,

COMPANY; LIMITED, KINGSW A-Y ENG-LAND; A

vnnERrEr-n na omnman s oxaa applic ion filed Mar To all whom 2'6 may correc ive: 7

Be it lgnoivn that I, lVnJ n J on y HU- BERT DIPLOC1-Z, a subject of the King of Great Britain, residing at Ingleside, Barclay Road, Croydon, in the county of Surrey, England, have invented certain new and useful Improvements in or Relating to Undert'eed Mechanical Stoker's, of which the following is a specification.

This invention relates to mechanical stokers for boiler and other furnaces, and refers n'iore particularly to multiple retort underleed' stokers of the kind inWVlli'Ill the fuel is fed into a plurality of troughs or retorts by means of reciprocz'iting rams, and in which tuyeres or other air emission means are provided for the admission of forced draught air into the fuel-as it rises from the retorts and spreads over the tops ot'the tuyeres. V

In multiple retort stokersot this character the several troiighs or retorts arefarranged above a main air supply chamber to which full pressurevair. under the controlof a sin le ClHHlJl is del er d by a fan and overfeed or extension grates are usually provided at the rear ends of the retorts, through which asupplementary supply of air under control and at reduced pressure is admitted to the fuel so that the final stages of combustion are completed upon the extension grates before the fuel is discharged, either aijiton'iatically'. or otherwise, over dump plates or other similarly acting devices, to the ashpit.

It has been found in practice that combustion tends to proceed more rapidly at some than at other parts'of the fuel bed, this'uneven combustion being principally due to the fact that the thickness of the fuel bed varies from time to time over different parts of the stoker," and the air admitted through the tuyeres or other air emission means tends to take the line of least resistance and accordingly to provide-an excess of air to the thinnest part of the fuel bed and an insuflicient supply to the thickest parts and it isthe chief object of the present invention to pro-mote even combustion over the entire fuel bed. i

According to one feature of thepresent invention the main air chamber is divided 7 up by means of partition Walls into smaller chambers, each chamberbeing provldedvvith 1 2 a-mi ax miea damper by means of which the volume of a'iir'supplied thereto from the main air duct ortroma common air chamber. in communication therewith, can be regulated as desired. It, therefore, combustion should take place at a more rapid rate in any particular zone of the furnace than in others, or, it any zone not receivingan adequate supply of air to he moiable to inclined positions in order toldirect air from thetront compartment directly tothe tuelbed above the next sue-, ceed'ing compartment Insome instances, it isdesirabletoprovide a supplementary air member beneath the extension grate, and when this is done a damper may be provided therefor and may be located at substantially thesa'me level asthe damper in the partition walljust referred to, whereby the air may have a direct ooursefroin the front compartment to the supplementary chamber beneaththe extension grate, 7 The aforesaid improvements may be applied to stokers provided with variable, strokepushers located withinithe retorts with, or Without moving retort side ivallstor the purpose of advancing and slicing the fuel or to stokers provided with agitating devices and \vith'or Without s nfaplementary air emission means.

i In order that the invention may be understood and readily carried intoetfect, the same ivillnovv beexplained more fully ini connection with the accompanying draw} ings, inifavhich, i

Figure l isa diagrammatic longitudinal section of a Stoker showing the invention applied thereto, and V Figure 2 is a transverse section of the same, taken on the line 4-t of Figure '1.

'teferring to the drawings, the invention is shownapplied more or less diagrammatically to a multiple retort under-feed Stoker,

blower, not shoWn.-- An air chamber-is ar-' ranged beneath the retorts M and tuyeres N, in the present instance, and is divided by a transversely disposed vertical partition 1-.[ into a front compartment G and a rear com partment G Air from the duct Gris admitted at the desired pressure through a damper I to the compartment G and part of it passes from the conipartment G "at the desired pressure through a damper H 1 to the compartment G J and J are convenient arrangements of links and levers by which the dampersI and H can be adjusted :as re quired.

It will be noted that the partition 11 is disposed adjacent the forward end of the main air chamber andsubstantially under that portionof the retorts where the fuel bed is usually thicker and humps up due to the fuel feeding mechanism.

It will be obvious that, as shown diagrammatically by the dotted lines in Figure 1, the fuel as it is fed into the stoker humps up and is thicker at the 1 front portion of the fuel bed, above the compartment G so that in order to penetrate the increased thickness of the fuel at this'point and promote perfect combustion, air should be supplied at a greater pressure than is required at the lower points of the fuel bed above the compartment where the fuel bed is thinner. Such adjustment as willberequired can be readily effected by the arrangement above described. 7

As is the usual practice in stokers, a supplementary air chamber or compartment K is provided beneath the extension grates K and a damper K is provided for regulating the amount of air entering this supplementary chamber. This damper K is shownf as being arranged at substantially the same level .as the, damper H ,so that when both of these dampers are open, the current of air from the front compartment G will pass more or less directly to the chamber K 'It will be obvious that instead of a single transverse partition H two or more partitions disposed at suitable distances apart and provided with dampers, may be provided so as tojfurther control the supply of air admitted at different points to the fuel bed;

'while the air instead of passing successively through the several chambers can, if 'de-.

sired, be conducted fromthesource of air supply through a longitudinally disposed duct to each of such other chambers.

In lieu of a single damper H as shown,

two or more dampers may also be employed,

while in order to direct the air upwardly into the compartment G a curved deflector plate L may be provided atthe baseof this air compartment. Shoots, riddling hoppers or other suitable means, not shown, having exit openings may b'e provided to facilitate the removal of any riddlings which may collect at the baseof the compartments (P and G, j Y I lVliat I claim and-desire to secure by Letters Patent of the United States is j 1. An underfeed stoker comprising an underfeed retort, an air chamber beneath said retort, tuyer'es located at. the sides of said retort foradmitting air into the fuel as it rises from the retort, a partition wall exbed for dividing the chamber into front and rear compartments, and a damper in said partitionwall' adjacent the top thereof and movable to deflecting positions to direct air from the front compartment directly to the fuel bed above the rear compartment. I

2. An underfeed stoker comprising an underfee'd' retort, an air chamber beneath said retort, tuyere-s located at the sides of said retort, a partition wall extending transversely in the chamber and arranged beneath. the forward end of the retort where the fuel bed thickest for dividing the chamber into two con'ipartments, and adamper' hinged at its loweredge to the upper portion of said partition, said damper being movable to in clined positions to direct air from the front compartment directly torthe fuel bed above the compartment beyond the partition.

An underfeed stoker comprising an underfeed retort, an extension grate at the rear end of said retort, a main air chamber beneath said retort, a supplementary air chamberrbeneath said extension grate, tuyeres located at the sides ofsaid retort for admitting air into the fuel as it rises from the retort, a partition wall extending transversely of said main air chamber and dividing the same into two compartments, a damper hinged at its lower edge adjacent the top of said partition wall, and a second damper for the supplementary air chamber arranged at substantially the same level as said first damper.

WILLIAM JOHN HUBERT DIPLOCK.

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