US2990790A - Stoker - Google Patents

Description

y 1961 G. N. MILLER 2, ,7

STOKER Filed Sept. 24, 1959 2 Sheets-Sheet 1 INVENTOR.

Fly GEORGE N. MILLER 1 M ATTO R N EYS July 4, 1961 G. N. MILLER 2,990,790

STOKER Filed Sept. 24, 1959 2 Sheets-Sheet 2 INVENTOR. GEORGE. N. MILLER k iii? ATTORNEYS United States Patent 1 This invention relates to automatic stokers for coalfired boilers. More specifically, this invention relates to an improvement of the stoker disclosed in US. Patent No. 2,563,688, granted to me on August 7, 1951.

The stoker disclosed in my previous patent provided an automatic mechanism for feeding pulverulent coal into a furnace in measured amounts calculated tomaintain a predetermined pressure in the associated boiler. This is accomplished by a reciprocating pusher which is actuated by a steam engine to carry coal frorn a hopper to iadistributing plate positioned in [the furnace whenever the pressure in the boiler falls below a predetermined level.- ;,The mechanism also includes steam jetpipes positioned adjacent the top surface of the distributing plate.

for blowing the coal from the plate over the fireibed and distributing it in a uniform manner.

.While the described mechanism was effective to distribute coal in an improved manner over the fire bed of a furnace, the structure possessed certain limitations which affected the operation and versatility of the apparatus, and which contributed to maintenance and repair costs. r t

-More particularly, there were no means provided in my earlier structure for preventing the two center jet pipes or nozzles from rotating out of their optimumposition in which coal would be blown over the bed in the -most effective fashion. I have found through continued operation of the stoker that occasionally the nozzles do rotate from their optimum position thereby resulting poor distribution and combustion. Heretofore, it has been necessary to either withdraw the stoker from the I furnace or manually adjust the jet pipes in order to return 7 the nozzles to their proper location.

Means for axially adjusting the center jet pipes, in-

cluding packing glands and sleeves surrounding the center pipes, were provided in my earlier apparatus. However, these means have not provided the degree of adjustability required when the stoker is used to fire a furnace having a long bed, thus making it necessary to blow the 'coal a considerable distance. Moreover, the packing glands have been found to have a relatively short life, and therefore serve to increase the maintenance costs.

Another disadvantage of my previously disclosed stoker construction is that the distributing plate which is bolted to the front wall of the furnace can not readily befreplaced. The difficulty in replacing the distributing plate whenit has become eroded by the impingement of the of a stoker such as disclosed in U.S. Patent 2,563,688 by 13 divides the furnace space into the customary fire box providing a removable distributing .plate and eliminatingotherimpenmanent Other objects and advantages of the present invention will become readily apparent as the same becomes better understood when considered in connection with the fol-f lowing detailed description and the accompanying drawings wherein:

and associated furnace. I

FIGURE 2 is a view taken along the line 22 of FIG.

1, looking in the direction of the arrows, with parts of the apparatus being eliminated for the sake of clarity. the distributing plate FIGURE 3 is a front view of taken in the plane of line 3--3 of FIG. 2.

FIGURE 4 is a fragmentaryfront view of a portion of the apparatus, the view being taken along the line 4-4 V of FIG. 2.

FIGURE 5 is an isometric view ing the jet pipes.

FIGURE 6 is a fragmentary isometric view of a portion of the apparatus showing rotation of the center jet pipes.

Referring now to FIG. 1, there is shown a boiler furnace 10 having a front wall 11 and a boiler 12. A grate the means for preventing 14 and ash pit 15.

The base plate, which serves as the main supporting structure for the apparatus, is supported at its outer end by form a tunnel-like structure finely divided coal and the steam jets has, resulted in relav tively expensive maintenance costs and longer shut-down times than are desirable.

,A generalobject of the present invention is to provide A an improved stoker which is capable of distributing coal v a uniform manner rein which pulverulent coal is blown over the bed of a furnace by steam issuing from the pipes.

Another object of the inventionis to provide a means for preventing the steamnozzles of the stoker disclosed;

in US. Patent 2,563,688 from rotating out of an optimum position in which coal is blown over the bed of a i furnace in the most efficient manner to promote combustion.

Still another object is to reduce the maintenance costs I side plates 21 and top plate a post 20 while the other end extends through opening 16 to a point substantially flush with the inner surface,

of front wall 11. The undersideof plate 17 is cored out at 18 to form depending flanges 19.

The inner portion of the base plate 1'7, together with 22, arranged and secured in the manner described in the tube. A coal hopper 24 and chute to the top plate 22 outside of the front wall 11, provide a means by which finely divided coal can be introduced 1 into the coal inlet tube.

Coal fed downwardly from the hopper through chute 23 is pushed along the coal inlet tube into the furnace by the reciprocating pusher is a single casting cored out on its underside to flanges 26. The pusher further includes pusher 25. In the form illustrated, the

form depending a top horizontal surface 27 and an upstanding leg 28 at its outer end. Preferably, the pusher 25 operates on a wear plate 31 which is secured to the horizontal surface The wear plate 31 is fastened to of the base plate 17. the base plate by screws or bolts (not shown) and may be readily replaced as it becomes worn.

A steam engine 32 havingits piston rod 33 connected.

to the leg 28 is provided for reciprocating the pusher 25.

Steam for operating the engine is tapped from the boiler 12 and passes through a pipe 35 which leads to the steam chest 34. A conventional olf-and-on regulator 36 having a weighted arm disposed in the drops below a level determined through adjustment of the weighted arm, the regulator opens to permit steam to 37 to determine its operating pressure is enter the steam chest thereby operating the engine to feed coal to the furnace. As the pressure in the boiler rises above the predetermined level, the regulator 'closes to shut ofi? the supply of steam to the engine.- A valve 38, serving as a throttle valve for the engine 3'2, is alsoar;

ranged in pipe 35.

: 7 Coal fed through the coal chute by the pusher onto a'distributin'g plate 43 in the manner illustrated in Patented July 4, 1961 FIGURE 1 is a vertical sectional view of the stoker of a slide for adjust- H above-identified patent, which serves as a coal inlet.

23, suitably secured pipe 35. When the pressure in the boiler FIG. 1. As shown, the distributing plate includes a horizontal, semicircular coal receiving surface 44 and an integrally joined, upstanding flange 45. The distributing plate is secured to the front flanges 19 of the base plate 11 by means of boltsor rivets 46 which pass through the flange 45. The construction is such that the distributing plate can be readily replaced when it becomes worn with a minimum amount of shut-down time and expense by simply elevating the base plate andwithdrawing it' from the opening 16; It will be apparent to those skilled inthe art that this form of construction constitutes a decided improvement over the structure in which the distributing plate was bolted directly to the inner surface of front wall 11, and thus was relatively inaccessible.

Positioned above the surface 44 of the distributing plate and extending through apertures in flange 45 to a point. outward of wall 11 are a plurality of jet pipes for blowing the coal from the distributing plate over the fire bed of the furnace. Four such pipes are shown, the outer two being designated by reference numerals 52 and the inner two by numerals 53.

Each of theouter pipes 52 is provided with a manually controlled valve 54, and has its outer end directly connected into a steam manifold 40. Steam for blowing and distributing the coal is supplied to the manifold by means of a pipe 39 which is in turn tapped into line 35 in the manner shown in FIG. 1.

In order that coal may be properly distributed over the fire bed regardless of its length, the center or inner pipes 53 are made axially adjustable. While all of the jet pipes may be made adjustable, I have found that movement of the inner pipes is adequate to assure optimum distribution of coal and proper combustion in furnaces of any depth. To this end, the closed outer ends of pipes 53 are connected to individual slides 55 which are movable toward and away from wall 11. As shown in FIG. 5, each slide consists of a rectangular casting having a handle 56 depending from one end, and an apertured bracket 57 for receiving the closed end of pipe 53.

Each pipe 53 is connected to the manifold 40 by means of a flexible line 60 tapped into the pipe at a point adjacent its closed end through a suitable fitting 61. The other end of the flexible line leads to a manually operated valve 62 which is connected to a short pipe 63 extending from the manifold 40. It will now be apparent that the jet pipes 53 can be quickly and conveniently adjusted longitudinally of the furnace by simply moving the associated slides to the proper position. The arrangement in which the pipes 53 are connected by flexible lines to the manifold instead of being connected directly thereto eliminates the necessity of employing the impermanent packing glands and the associated relatively complex structure such as was disclosed in my prior patent. Moreover, the present construction provides greater extensibility of the pipes than was heretofore possible.

As shown in FIGS. 1, 2 and 4, the manifold 40 is shown as being mounted on the upper surface of the post 20 between side flanges 19 of base plate 17. The slides 55 are also supported by post and are reciprocally received within grooves 58 formed in the bottom of the manifold. Set screws 59 threaded through the upper surface of post 20 into engagement with the slides serve to maintain the slides in their adjusted position.

Referring now to FIG. 6, it will be observed that the inner end of each pipe 53 is threadedly engaged in a collar 64 as is a short pipe 67 having a flattened end portion 68 which serves as a nozzle. Each collar includes a cylindrical body portion 65 having an integral slide or key portion 66. Each key portion is slidably received in a slot 70 formed in surface 44 of the distributing plate. The co-operating slots and keys serve to prevent the nozzles 68 from rotating out of their desired location when positioned in the furnace, and also to hold the associated pipes 53 in a straight horizontal line. The

7 of the coal over the fire bed by adjusting the longitudinal position of pipes 53 through the agency of slides 55. At the same time the nozzles 68 are rotated to secure the correct lateral distribution of the coal, and the keys 66 positioned in slots 70. When subsequent adjustment of pipes 53- becomes necessary, the set screws 59 need only to be loosened, the slides moved to their desired positions, and the screws retightened.

Having thus adjusted the various parts of the stoker, the operation of the pusher, together with the supply of steam to the jet pipes, is automatically controlled by the pressure regulator in response to the boiler pressure.

Various modifications are contemplated and obviously will be resorted to by those skilled in the art without departing from the spirit and scope of the invention as defined by the appended claims.

What is claimed is:

1. A steam boiler comprising a boiler unit, a fire box, a front wall having an opening communicating with said fire box, an elongated base plate having an inner end sub stantially flush with the inner surface of said wall and an outer end extending beyond the outer surface of said wall, a post supporting said outer end of said base plate, a coal hopper and chute supported by said base plate, a distributing plate positioned within said fire box, said distributing plate having a horizontal coal-receiving surface and an integrally joined, upstanding flange formed with horizontal apertures therethrough, said flange being secured to the inner end of said base plate, a coal pusher reciprocally mounted on said base plate for pushing coal from said chute to said distributing plate, means for operating said pusher, a plurality of steam jet pipes for blowing coal from said distributing plate, said pipes being horizontally disposed below said base plate and having inner ends extending through said apertures in said flange, a collar threaded on the inner end of at least one of said pipes, a key mounted on said collar, at least one longitudinally extending groove formed in said coal-receiving sunface for slidably receiving said key, a nozzle fastened to said collar in coaxial alignment with said one pipe, a steam manifold supported by the post, connecting means between said pipes and said manifold, said connecting means between said one pipe and the manifold comprising a flexible steam line, a slide connected to the outer end of said one pipe, said slide being reciprocally mounted on said post below the manifold for movement toward and away from said wall, and steam supply means for said manifold.

2. A steam boiler comprising a boiler unit, a fire box, a front wall having an opening communicating with said fire box, an elongated base plate having an inner end substantially flush with the inner surface of said wall and an outer end extending beyond the outer surface of said wall, a post supporting said outer end of said base plate, a coal hopper and chute supported by said base plate, a distributing plate positioned within said fire box, said distributing plate having a horizontal coal-receiving surface and an integrally joined, upstanding flange formed with horizontal apertures therethrough, said flange being secured to the inner end of said base plate, a coal pusher reciprocally mounted on said base plate for pushing coal from said chute to said distributing plate, means for operating 'said pusher, a plurality of steam jet pipes for blowing coal from said distributing plate, said pipes being horizontally disposed below said base plate, and having inner ends extending throughsaid apertures in said flange,

a steam manifold supported by the post for supplying steam to said pipes, at least one of said pipes having its outer end terminating short of said manifold, connecting means between said pipes and said manifold, said conneoting means between said one pipe and said manifold comprising a flexible steam line, a slide connected to said one pipe, said slide being reciprocally mounted on said post below said manifold tfOI' movement toward and away from said wall, and steam supply means for said manifoldl 3. In a steam boiler having a boiler unit, a fire box, a front wall having an opening communicating with said fire box, an elongated base plate positioned in the bottom of said opening, said base plate having an inner end sub stantially flush with the inner surface of said wall and an outer end positioned beyond the outer surface of said wall, a post supporting said outer end 01f said base plate, a coal hopper and chute supported by said base plate, and a pusher reciprocally mounted on said base plate for pushing coal from the end of said chute to the inner end of said base plate, the improvement comprising a distributing plate in said fire box, said distributing plate having a horizontal coal-receiving surface positioned below the inner end of said base plate and an integrally joined, upstanding flange fastened to the inner end of the base plate, said flange being formed with horizontal apertures therethrough, said distributing plate being supported independently of said wall whereby said distributing plate can be easily removed from said fire box by withdrawing said base plate from said opening, a plurality of steam jet pipes for blowing coal from said coal-receiving surface, said pipes being horizontally disposed below said base plate and having inner ends extending into said fire box over said coal-receiving surface through said apertures in said flange, a collar threaded onto the inner end of at least one of said pipes, a steam nozzle threaded into said collar in coaxial alignment with said one pipe, a key mounted on the outer surface of said collar, and at least one longitudinally extending groove formed in said coalreceiving surface for slidably receiving said key for preventing lateral movement of said inner end of said one pipe and for preventing rotation of said collar, the outer end of at least said one pipe being connected to a slide reciprocally supported on said post whereby said one pipe may be removed longitudinally of said fire box, and steam supply means for supplying steam to all of said pipes.

References Cited in the file of this patent UNITED STATES PATENTS 2,034,590 Myers Mar. 17, 1936 2,281,765 Hanna May 5, 1942 2,563,688 Miller Aug. 7, 1951 2,807,223 Miller et a1. Sept. 24, 1957

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