US1731771A - Stoker - Google Patents

Description

Oct. 15, 1929. R. A. FORESMAN 13 7 STOKER Filed Nov. 11, 1926 2 Sheets-Sheet 1 R.A.Frcsman WITNESSES: v INVENTOR 6% BY a ,6

' ATTORNEY Oct. 15, 1929. R. A. FORESMAN STOKER Filed Nov. 11, 192

2 Sheets-Sheet 2 WITNESSES 2 741.20%)

ATTORNEY Patented Oct. 15, 1929 I ROIBERT A. FORESIVIAN, OF MOORES, PENNSYLVANIA, AS SIGNOR IO WESTINGHOUSE PATENT oFFrcE ELECTRIC & MANUFACTURING COMPANY, A CORPORATION OF PENNSYLVANIA STOKER Application -filed November 11, 1926. Serial No. 147,810.

My invention relates to stokers, more particularly to stokers of the progressive fee d type having associated therewith a clinker pit for receiving the refuse from the fuel after ts passage through the stoker, and has for 1ts object the provision of an improved grate section for a stoker of the class described, efi'ective for producing a more thorough combustion of the fuel in its final stages of combustion. 0

A further object of my invention is the provision of an overfeed section ad acent the clinker pit of a stoker of the class described and effective to break up the refuse and shove it down into the pit in the final stages of combustion and which shall be free from danger of overheating inoperation. These and other objects are attained by apparatus made in accordance with my invention and illustrated in the accompanying drawings wherein, L Fig. 1 is a longitudinal sectional view of a stoker having my improved grate applied thereto; I

- Fig: 2 is a detailed sectional view showing the construction of the overfeed' section; and Fig. 3 is a plan view of the overfeed section shown in Fig. 2. r

Difficulties have been encountered in the operation of stokers of the progressive feed type having clinker pits associated therewith, due to 'difliculties in effecting breaking up of the slagging mass of fuel in its finalstages of combustion and in supplying sufiicient air for combustion of the fuel in the final stages' thereof. Furthermore, where means for agitating the grate section adjacent the clinker pit are employed, difliculties have been encountered due to the burning off of the grate clinker pit and by. providing for said over feed grate section a combined oscillatory and reciprocatory motion. The final grate of the series, or the grate adjacent to the clinker pit, is provided with a relatively large cooling surface area in proportion tothe surface sub.- jected to the heat of the fire and as a result it is not ,in danger of overheating due to its coming in contact with the burning refuse. Further novel features of the grate structure res1de 1n the provision of an air sealing member beneath the final grate member and in the disposal of the air sealin member in such. a manner as to cause any siftingswhich might pass through the grate to be moved rearwardly into the clinker pit. 7

Referring now to the'drawings for a better understanding-of my invention I show in Fig. 1 a stoker of the progressive feed type having associated therewith 'a clinker pit 11 for the reception of refuse from the fuel after tuyere banks 12 and 13, respectively, comprising an underfeed section. Disposed between the underfeed section and the clinker pit 11 is my improved overfeed grate structure.

The overfeed grate structure includesan oscillatin grate 15 which in turn includes a hollow frame member 16 rigidly-secured to a rock shaft 17, as by means of, U bolts 18.

On the forward end qf the frame member 16 is a cover 19 having a rounded outer contour fitting into a similarly formed recess 20 formed in the rearward end of the casting supporting the tuyere bank 13.

The cover 19 is provided with a suitable number of slots 21 for the passage of air from an air box 22 intov the interior of the frame member 16. Extending across the top of the frame member 16 is an upper grate member 23. The grate member 23 is secured to the frame 16 by means of bolts 24. The underside of the grate. member 23 is provided with a suitable number of slots or grooves 25 I for the passage of air to the fuel above the grate. Adja'cent the grate member 23 are .a pair of grate members 26 and 27. The grate members 26 and 27 are secured to the frame 16 inpairs by means of lugs 28 formed on their underside'and into which pins 29 are inserted. The pins 29 pass through suitable holes formed in said frame member and are held in place by cotter pins 31. The grate members 26 and 27 are provided with slots or indentations 32 on their under, rearward, sides for the passage of air from the interior of the frame member to the fuel above them.

The overfeed grate structure includes inaddition to the oscillating grate 15, just described, a plurality of final grate members 33, which are pivotally connected at 35 to the grate member 15. These grate members 33 extend across the width of the grate 15 as shown. The grate members 33 are each provided on their underside with a web portion a 34 which strengthens them and adds to their cooling surface area. In the lateral edges of each of the grate members 33 are provided suitable grooves such as 36 for the passage of zfiirlfrom beneath the grate member to the 7 ue In the operation of the stoker, air enters through the passage 21 and passes through the frame member 16 to the space beneath the grate members 33. In order to prevent a leakage of air from beneath the grate members, away from the fire, and in order to provide for the disposal of any ashes which might shift downwardly between the grate members, I provide a sealing member 37 The sealing member 37 is hinged to the lower side of the frame member 16 at 38 so that it may oscillate about the hinged point 38 as an axis. The rearward end .of the sealing mem-- ber 37 rests on the edge of the clinker pit at 41 and extends beyond the ends of the grate members 33.

It will be apparent from the foregoing description that, when the shaft 17 is oscillated, the grate 15 oscillates about said shaft as an axis taking with it the grate members 33 which oscillate about their hinges or pivots 35 asaxes. The rear ends of the grate members 33, together with the sealing member 37, slide back and forth on the support 41 so that they have a'combined oscillatory and,re-ciprocatory motion. .The motion just referred to serves to break up the fuel bed immediately above the overfeed grate section and ,to shove the broken up refuse downwardly into the clinker pit 11. The sealing member .37 is given a downward slope toward the clinker pit so that any siftings of ashes through the grate members .33 are carried downwardly into the clinker pit.

Any suitable means may be employed for imparting motion to the overfeed grate seo tion. For example, I show in dotted lines in 1, as being beyond the furnace, a cylan arm 54 secured to the shaft 17. As the piston 52 reciprocates back and forth, the frame 19 and its associated grate members is oscillated about the shaft 17 as an axis causing a movement of the rear thereof in an arcuate path, carrying with it the forward ends of the grate members 33. As the forward ends of the grate members 33 are raised and lowered by the rear of the frame member19, the rear ends of the grate members 33 are given a reciprocatory motion.' Fuel in the final stages of combustion is thus broken up by the vertical component of motion given-to the overfeed grate section, while the refuse is shoved downwardly into the pit by the reciprocatory motion of the grate members 33.

The action just described insures that the refuse shall bebroken up into relatively small pieces and shall entirely fill the pit leaving no voids adjacent the walls of the pit which would be conducive to the admission of an excess of cold air into the rear of the furnace which could serve no useful purpose in supporting combustion. Such voids would also allow the small particles of combustible matter which lie on top of the non-combustible matter in the pit to trickle through the pit and be lost in the ash. The elimination of these voids, it is plain, would result in less loss of carbon in the as From theforegoing description, the operation of apparatus made in accordance with my invention will be apparent. Fuel is fed continuously into the stoker in 'a-suitable manner, not shown, and passes through the underfeed section comprised of the alternate retorts and tuyere banks 12 and 13 from whence it is finally discharged onto any improved ove'rfeed grate-section. On passing onto the overfeed grate section the oscilla tion of the shaft 17 raises and lowers the rearward end of the frame member 16 and this final combustion passes to the fuel thro gh the rear of the-frame member 16 and through the grooves 36 and is prevented from leaking away from the fire by means of the sealing member 37 beneath the grate 33. Ashes sifting down through the link grates 33 are moved downwardly to the end of the clinker pit by means of the agitation of the sealing member 37. 4

From the foregoing, it will be apparent that I have devised animproved overfeed grate section for a stoker effective for eflicient burning of fuel in the final stages of combustion effective for breaking up the clinkers into small particles formed in said process and for pushing the clinkers rearwardly into the clinker pit without forming objectionable voids.

While I have shown my invention in but one form, it will beobvious 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, and I desire, therefore, that only such limitations shall be placed thereupon as are imposed by the prior art or as are specifically set forth in the appended claims.

What I claim is:-

1. In combustion apparatus, the combina-' ,tion of a clinker pit; an overfeed grate secher and pivotally connected to the frame member; said plate member extending rearwardly and beyond the rear grate, member;

means adjacent the edge of the clinker pit for supporting the rear grate member and the plate member; and'means providing for the movement of said frame member about its pivotal support.

2. In a furnace, the combination of an overfeed grate section comprising a relatively wide grate pivotally supported at its forward end and a plurality of relatively narrow grate members arranged in side-by-side relation and pivotally connected at their forward ends to the rear end of the relatively wide grate; means for sealing the underside of the relatively narrow grate member against air leak-' age away from'the fuel bed; means for slidably supporting the narrow grate members; and means for moving the wide grate member about its pivotal support.-

3. In a furnace, the combination with progressive underfeed 'stoker section, and a clinker pit; of an overfeed grate section extending from the discharge end of the under feed section to the clinker pit and comprising a forward hollow grate pivotally supported at its forward end and a rear grate member pivotally connected at its forward end to the rear end of the hollow grate; the forward hollow grate and the rear grate being provided tending underneath the rear grate; means for slidably supporting the rear grate and the air seal member; and means for moving the hollow grate about its pivotal support. I

4. In a furnace, the combination of an overfeed grate section comprising a relatively wide hollow grate having air supply passages in its fuel-supporting surfaces and being pivotally supported at its forward end, a lurality of relatively narrow grate mem ers having air passages therethrough and being disposed in side-by-side relation and being pivotally supported at their forward ends to the rear end of the hollow grate, and means for admitting air to the interior of the hollowsv 8 of grate members detachably mounted on the grate frame and disposed in overlapping relation to one another; the overlapping portions of the grate members" being provided with grooves communicating at their inner ends with the interior of the hollow grate frame to provide air passages; and a plurality of relatively narrow, downwardly-curved grate members disposed in abutting side-by-side relation and each pivotally connected at one of its endsto the end of the hollow grate opposite the pivotal support of the latter; the relatively narrow grate members having grooves formed on their, abutting facesito provide air passages.

In testimony whereof, I have hereunto subscribed my name this tenth day of November,

ROBERT A. FORESMAN.

with air passages for supplying air for supporting combustion to the interior of the furnace; an air seal member pivotally connected to the underside of the hollow grate and ex-

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