US733397A - Underfeed mechanical stoker for fire-chambers of furnaces, &c. - Google Patents

Description

PATENTED JULY 14, 1903.

E. W. JONES. UNDBRFEED MECHANICAL STOKBR FOR FIRE CHAMBERS 0F FURNACES, 8w.

APPLICATION FILED JAN. 28. 1895.

N0 1mm.

2 SHEETS-SHEET l.

INVENTOR WITNESSES No. 733,397. PATENIED JULY 14, 1903.

E. w. JONES. UNDBRFEED MECHANICAL STOKBR FOR FIRE CHAMBERS OP FURNACES, 6w.

' APPLICATION FILED 1:311:28. 1895.

NO MODEL. 2 SHBETSSHEET 2.

INVENTOR "45 wnws. Finns no. mouYno.wAsmuutou, n. c.

UNITED STATES K Patented July 14, 1903.

PATENT OFFICE.

EVAN "W. JONES, OF PORTLAND, OREGON.

SPECIFICATION forming part of Letters Patent No. 733,397, dated July 14, 1903.

Application filed January 28, 1895. Serial No. 536,471. (No model.)

To (ZZZ whom it may concern.-

Be it known that I, EVAN WV. JONES, a citizen of the United States, residing at Portland, in the county of Multnomah and State of Oregon, have invented certain new and useful Improvements in Underfeed Mechanical Stokers for Fire-Chambers of Furnaces, &c.; and I do hereby declare the following to be a full, clear, and exact description of the invention, such as will enable others skilled in the art to which it appertains to make and use the same.

My invention relates to improvements in underfeed mechanical stokers of the type patented to myself by Letters Patent of the United States, No. 470,052, dated March 1, 1892.

The invention consists of the combination in a furnace of an underfeed fuel-magazine, a reciprocating plunger or ram for supplying the 'same with fuel, and fuel agitating and lifting devices mounted in said magazine and adapted to be operated by the reciprocating ram, so that the fuel is forced upward evenly along the entire length of the magazine, and means for operating the ram.

It also consists of the combination in a furnace of an underfeed fuel-magazine, a plunger or ram for supplying fuel to the same, twyer-pipes arranged along each side of the fuel-magazine and movably connected to the same, so as to be-capable of longitudinal expansion, removable twyer-caps attached to the tops of said pipes and provided with airpassages, and means for operating the ram.

It also consists of certain other novel constructions, combinations, and arrangements of parts, all of which will be hereinafter more particularly set forth and claimed.

In the accompanying drawings, forming part of this specification, Figure 1 represents a broken central vertical longitudinal section of my invention as applied to a boiler-furnace. Fig. 2 represents a transverse vertical section of the same on the line :0 a: of Fig. 1. Fig. 3 represents a transverse vertical section of my said devices on the line 1 y, Fig. 1. Fig. 4 represents a broken central vertical longitudinal section of my said invention, showing a slightly-modified arrangement of the twyer-pipes and their connection with the blower. Fig. 5 represents atop plan view of the same. Fig. 6 represents a vertical transverse section of the devices illustrated in Fig. 4.

A in the drawings represents afuel receiving and feeding magazine, into which the fuel is forced by a ram or plunger B. Said magazine is formed substantially, as shown in the drawings, with an air-tight bottom a and airtight upwardly and outwardlyinclined or flaring sides a, said inclined sides being either parallel to one another or slightly diverging from front to rear, and an upwardly and rearwardly inclined rear wall a a are provided with flanges e at their tops to facilitate their connection with tWyer-pipes G, which serve the double purpose of conducting the air to the discharging-orifices of twyer-caps c and forming a part of the side walls of the fuel-magazine when bolted, as shown, to the flanges e of said magazine, the inner walls of said twyer-pipes being inclined for this purpose.

The magazine A has an opening a at its front end, which opening receives the forward end of a plunger-cylinder B. The upper side of this plunger-cylinder is provided with an opening d through which the fuel is discharged into said cylinder from a feedhopper D, mounted upon the same just above said opening.

The plunger or ram B is reciprocated by any suitable and convenient power, either independent of or connected to the engine or boiler; but I prefer to use a small steam-engine, as shown at A in the drawings, for that purpose. The piston of this engine is connected to the plunger or ram by piston-rod a When the ram is Withdrawn back of the opening d, a portion of the coal discharges from the feed-hopper D into the cylinder B, and as said ram moves forward this coal is forced into the feed-magazine. The bottom of the magazine A is provided along its entire length with a groove (0, into which is loosely fitted a bar (P, which is adapted to reciprocate longitudinally in said groove. The forward end of this bar is secured in any substantial manner to the under side of the plunger or ram B, but preferably, as shown in the drawings, by bolts (9. The inner end of the cylinder B The side walls is enlarged, so as to make it approximately bell-mouthed. Through an opening in the flange that connect-s this cylinder with the flange on the magazine 13 the bar a passes before entering the groove a Along the under side of this cylinder B is a slot Z), in which an interposed plate 1) or an enlargement on the side of thebar a for connecting the bar and plunger is adapted to slide. The object of' connecting the bar a to the under side of the plunger or ram and causing it to work below and outside of the cylinder B is to prevent said bar from carrying the fuel backward during the back stroke of the plunger or rain. The bar a is prevented from rising out of its slot a by plates D, which are bolted to the bottom of the magazine transversely over the top of said groove at the desired intervals. At suitable points on bar (t are secured solid agitators orlifters D, having reversely-inclined sides. In practice when areciprocating motion is given to the plunger B for the purpose of feeding coal into the magazine A the same motion is imparted through bar a to the lifters D, and they loosen and lift the fuel from the magazine into the fire-box above, thus preventing the packing of fuel in the rear end of the magazine. By means of these lifters the fuel is elevated and fed to the fire-box evenly along the entire length of the magazine. It will be seen from this construction that I can make the magazine B of any desired length and secure to the bar (L5 a correresponding greater or less number of lifters D. These lifters are not depended upon to force the fuel back into the magazine, their function being, simply to loosen and lift the fuel from the bottom of the magazine and distribute it evenly. Tho plunger or ram B forces the fuel into the magazine from the feedhopper, and the lifters D then distribute and lift the'fuel out of the said magazine and over the tops of the twyer-pipes 0 onto the side plates E.

The twyer-pipes C are two independent pipesone on each side of the magazine. They extend the whole length of the magazine, forming a part of the side walls of the same, and pass out through the boiler-front, where they are connected together by pipe (3, that leads to'any suitable blower, (not shown,) the other ends of these twyer-pipes thus being left free to expand and contract because of the great heat to which they are subjected.

Said twyer-pipes are connected to the flanges of the magazine A by bolts which pass through elongated slots a in said flanges, and thus the expansion of said pipes is provided for.

In Figs. 4, 5, and 6 is shown a modification of the arrangement of air-pipe connection, in

which the branch air-pipe c connecting the twyer-pipes, is located at the rear end in the ash-pit. The forward end of the twyer-pipes in this case extend through the front of the furnace and are free to expand and contract and are provided with removable covers,

whereby the accumulated ashes and dust in said pipes may be blown or removed from the same. On the upper sides of the twyer-pipes are arranged a series of rectangular blocks or caps 0", each provided with a deep depression 0 on its upper surface. Each twyer-pipe has a partition 0 between each block to strengthen and support the upper side of said pipe and atthe same time provide a snug seat for said caps. The said caps have slotted openings 0 in their upper inner edges that permit air under pressure from the inside of the twyerpipes to enter the furnace, substantially as indicated by the arrows'in Fig. 6. The object of the depressions in the tops of the caps O is to provide a receptacle which will soon be filled with slag or cinder, whereby a protection is afforded for said caps against the great heat to which they are subjected.

I have illustrated two means for securing the caps G into the tops of the twyer-pipes. The first of these consists in providing said caps with staples or eyelets d and passing a rod (1 longitudinally through the twyer-pipes under the partitions in the tops of the same and through said eyelets or staples, as shown in Figs. 1 and 2. The second consists in providing each twyer-pipe internally with a longitudinal bar or strap (i and securing said caps to said strap by bolts (1 as shown in Figs. 4 and 6.

A deflecting-plate Gsupports the brickwork at the forward end of the magazine and acts as a dead-plate. Slides H (shown in dotted lines in Fig. 1) are provided on the outside of each of the twyer-pipes, so as to normally close openings h in said twyer-pipes. When these slides are withdrawn from over the openings h, any dirt or cinders that has found its way into the inside of the twyer-pipes can be blown or removed therefrom. The side deadplates E extend the whole length of the furnace and are used in some cases instead of the side grates. When the twyer-pipes are connected to the blower in the rear, as shown in the modified form of my invention, a damper or slide J is arranged in the pipe communicating with the blower, so that the amount of air admitted to the said twyerpipes can be regulated at will. This damper or slide is operated by a bell-crank leverj and connecting-link j in conjunction with an operating-rod i which passes forward to the front of the furnace, where it is notched, as at 7' so that it may be secured at this end in any adjusted position by said notches engaging, respectively, a cross-bar.

I find by experience in operating stokers of this type that in order to get the best results the fresh fuel should be discharged into the fire-box along the entire length of the same and that fresh fuel should constantly replace the fuel so discharged into the fire-box. I also find that it is an advantage where a large amount of fuel is to be burned that the firebox and fuel-feeding magazine be of considerable length in order to secure a long fire,

thereby spreading the fire over a considerable space, and thus providing an ample area for the introduction of air under pressure over the green fuel and under and through the burning fuel. Owing to the considerable length required for the fire-box and the fuel-magazine and the fact that the latter is supplied with fresh fuel through an admission-opening at the extremefront end, I find that the frictional resistance offered to the passage of the coal along the length of the magazine tends todeliver more fuel near the front of the fire-box than at the rear, thus causing an unequal distribution of the fuel. I also find that unless some provision is made for the expansion of the twyer-pipes under the great heat to which they are subjected they will ultimately split or crack, and thus become useless by allowing the air to escape therefrom at points where such an escape is useless and even harmful, as any air introduced into the green fuel below the tops of the twyer-pipes will cause combustion in said green fuel below the point that it is intended the combustion should begin.

In my construction of the twyer-pipes discharging at the top of the fuel-magazine the air issuing from said pipes is thoroughly commingled with the gases arising from the heated green fuel in the magazine and forced through the burning mass of fuel above the magazine, and thus said gases are thoroughly consumed and prevented from escaping and at the same time serve to promote the combustion of the burning fuel through which they pass.

It must be understood that in order to get the desired results the magazine A must necessarily be long and narrow for the reason that the space between the twyer-pipes is limited to the distance which the air undera low pressure can be forced through the burning fuel, as it is obvious that if this distance is so great that the air from the opposite twyerpipes will not meet in the center before it reaches the top of the mass of burning fuel green fuel will be forced up through the center of the mass of burning fuel, because it will not be provided with the air necessary to support its combustion, and one of the principal objects of this invention would be defeated. For this reason Iprovide my peculiar arrangement of elongated fuel-magazine with long twyer-pipes arranged on upper edges of same and means for distributing the fuel equally throughout the whole length of said magazine and means for the introduction of air directly over the green fuel but under and through the burning fuel.

I do not consider it to be broadly new with me to construct a mechanical stoker with a .retort or fuelmagazine having twyers to which air is supplied adjacent to its upper inner edges, associating a primary feed mechanism with said retort, and providing an auxiliary feed mechanism in the retort.

Having now described my invention, what I claim as new, and desire to secure by Letters Patent, is

1. In an underfeed mechanical stoker designed to force fresh fuel from belowinto' the burning fuel, an elongated fuel magazine having outwardly-flared sides and rear end, and provided at the top with slotted horizontal side flanges, twyer-pipes mounted on said flanges, and connected thereto by bolts which slide in the slots thereof, a reciprocating plunger or ram for supplying the same with fuel, agitating and lifting devices mounted in said magazine and connected to the plunger or ram, and a deflecting-plate arranged above the forward end of the fuel-magazine, substantially as described.

2. In an underfeed mechanical stoker designed to force the fresh fuel from below up into the burning fuel, an elongated fuel-magazine having outwardly-flared sides and rear end, and provided at the top with slotted horizontal side flanges, twyer-pipes mounted on said flanges, and connected thereto by bolts which slide in the slots thereof, agitating and lifting devices mounted in said magazine, a plunger or ram for supplying green fuel to the magazine and connected to the agitating and lifting devices, a deflectingplate mounted above the forward end of the magazine and side dead-plates adapted to receive the fuel discharged from the magazine, substantially as described.

In testimony whereof I hereunto affix my signature in presence of two witnesses.

EVAN W. JONES.

Witnesses:

J. O. RUTENIC, BEATRICE SWAIN.

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