US1986662A - Furnace - Google Patents

Description

Jan. 1, 1935. E G, BA|LEY` 1,986,662

' FURNACE Original FiledMarch 17, 1928 5 Sheets-Sheet l ATTORN EYS 3 Sheets-Sheet 2 INvr-:NToR

ATTORNEYS A E. G. BAILEY FURNACE Original Fi led March 1'7, 1928 Jan. 1, 1935.

Jan. l, 1935. E. G. BAILEY 1,986,662

i FURNACE Original Filed March 17.11928 3` Sheets-Sheet 3 INVENTOR Erl/in G.' Bailey BDERXM ATTORNEY pulverized coal, which in burning forms slag,`

Patented Jan. l, 1935 UNITED STATES PATENT OFFICE' FUBNACE Ervin G. Bailey, Easton, Pa., assignor to Fuller Lehigh Company, Fullerton, Pa., a corporation of .Delaware Application March 167,

1928, Serial No. 262,363

Renewed October 7, 1932 22 Claims.

trouble has been experienced in disposing of the slag which is depositedvin the bottom of the furnace directly from the burning fuel, or else gathers on the walls of the furnace and runs down onto the floor.

The accumulation of slag on the floor is added to by chunks`of slag which may collect in the furnace above the floor and then drop down when they become loosened from the'tubes. The slag on the floor, when it becomes cool, fornis a solid mass of extremely refractory material which is difficult to remove, and it is to the removal of such slag that m`y invention ls directed.

f In the accompanying drawings, in which I have shown a selected embodiment of the invention:- Fig. 1 is av vertical sectional view through the lower part of a furnace, constructed according to my invention. i

Fig. 2 is a fragmentary section line 2'2-2 -of Fig. 1.

Fig.- 3 is a fragmentary elevation on an enlarged scale, and showing the interior of the furnace wall at the slag tapping opening.

Fig. 4 Vis a sectional view through the slag tapping opening, being taken on theV lines 4-4' of Figs. 2 and 3.

Fig. 5is a fragmentary elevation ofthe outer taken on the face of the furnace'wall at the slag tapping and access openings, and taken on the line 5--5 of Fig. 2.

Fig. 6 is a section on the line 6-6 of Fig. 4.

Fig. 7 is a sectional elevation illustrating the furnace shown in Figs. 1-6 as incorporated in a steam generator or boiler;

For the purposes of illustration, I have shown my invention 4as applied to `a furnace having substantially vertical walls, of whch` are shown three, 1, 2 and 3, each of which is formed by vertically extending waterI tubes 4, 5 and 6, re-

spectively, connected at their lower ends to headers 7, 8 and 9 to which an appropriate covering may be applied. 'I'he upper ends ofthe water i tubes are connected vto theusual -upper headers (see Fig. '7) Normally water is admitted to the lower header rising through the tubes in the wall' where some steam will be formed. Steam and water are discharged from the upper header. Such furnace walls would normally form part of a steam boiler and as such are ltermed water walls.

AIt will be noted that` each of the lower headers,

is independent of the others, whereby eachwall may expand and contract in a vertical direction independently of the others, and the lower headers are preferably carried on spring supports 10. The covering for the wall tubes may comprise individual tile or blocks 11, which are best shown in Figs. 4 and 6, these blocks being formed with refractory faces 12 and metallic backings 13 which are in close engagement with the tubes, where 'they are held by suitable clamps 14. The details of the blocks and clamping means have been omitted from Fig. 2,'forv the sake of clearness. andbecause of the small scale' of this figure.

The floor of the furnace is supported upon suitable beams 15 and sometimes-comprises a single course of brick 16, although in the illustrated embodiment two courses are shown. Upon this course is preferably placed a layer of dolomite 17, and the course of brick is preferably laid loosely on the supporting plates 18 disposed on the beams15.

Adjacent the edges of the floor, the plates 18 upon which the brick work is supported, extend substantially into `contact with the side walls, as best shown in Fig. 4. The brick work course 16 is provided with expansion joints 19, which are covered by a plurality of courses 20 extending along the walls.

In one or more of the side walls is disposed a burner indicated generally at 21, and which is preferably adapted to burn pulverized coal. The

burner should preferably be one which will give great turbulence to the incoming fuel, and it will be noted that the burner is so arranged as to project a flame horizontally and relatively close to the floor. 4

Y In the embodiment shown, I contemplate placing a burner in each wall substantially in the posi- Jtion shownfso that the flamestherefrom will intersect within the furnace and in such a. way as to cause still greater turbulence than is present in the individual streamsof fuel, thus providing thorough'mixture of the air and fuel, and comi plete combustion of the fuel.

The burning fuel will form slag, as is wen known imity of the streams of burning fuel which, as,

noted above, are relatively close to the floor, and therefore maintain the temperature of the slag on the floor sufllciently high, to keep it in its molten state.

`The slag is preferably tapped through a suitable opening in one of the fluid cooled walls indicated at 22, from which .it runs down a spout 23 associated with the opening 22. This spout is preferably formed of two sections, as best shown in Fig. 4, one section being supported between ears 24 and the other being pivoted at 25 upon these ears 24, and being provided with an apron 26 which, when the outer section 23' is lifted, will close the end of the inner section of the spout.

Tapping of slag is intermittent, and between tapping periods the level of the slag pool rises, thereby completely submerging the floor and whatever may be upon it. By the rising and falling of the slag level the contents may be thoroughly mixed in a molten condition through a process of liquid diffusion.

The tapped slag may be permitted to run into a sluiceway, where it may be subjected to jets of water which will break it up and carry it away, or it may be tapped directly into a stream of running water. Again, it may be run on to the floor and quenched, or may be handled in any'other suitable way. The slag at the opening 22 forms a crust of chilled slag which may be easily broken by a bar, in order to permit the flow of slag, and then the slag may be permitted to run until the crust forms again and there is insufcient pressure behind it to break it, or if desired, the hole may be plugged, to stop the ow of slag before the crust would form by itself. In this connection, it should be noted that the spout forms a convenient guide and rest for a bar used in working at the tap hole.

Adjacent the tap hole, I preferably provide an access door indicated at 27. Normally, this door is bricked up as shown in Figs. 1 and 2, the brick being removed when it is desired to enter the furnace through the door.

Disposed in front of the two openings formed by the door and the tap hole, and spaced from the wall of the furnace, is a transversely extending header box 28. 'Ihis box preferably extends beyond both openings and is connected to the wall tubes above these openings, these tubes being bent outwardly as best shown in Fig. 4, and expanded.

into the box.

Disposed beneath the door 27 is a second transversely extending header box 29, connected by nipples 30 to the header 8. The boxes 28 and 29 are connected by nipples 31 disposed on opposite sides of the door 27. Disposed on opposite sides of the tap hole are two nipples 32, which connect the header 8 to the box 28. By the above arrangement, a convenient disposition of the access door is provided, and proper circulation of water past both the access door and'tap hole is also obtained. At the same time, the tubes are disposed far enough from the tap hole to prevent their chilling the slag and thus preventing or hindering its ow.

Air may be introduced -beneath thev iioor through the conduit 33, to aid in maintaining the floor and the supporting steel work relatively cool.

In operation, the furnace is started and as the slag accumulates on the floor, it is maintained in a molten condition by the intense heat of the fire which is relatively close to the floor. It will be noted that the dolomite covering forming part of the floor is extended upwardly toward the walls, as best shown in Fig. 1, this material being installed loose.

As the slag accumulates and reaches a point above the tap hole, it may be tapped off if found desirable.' If it is vintended to use the slag for manufacturing purposes, as an ingredient in a composition of matter for which it may be suitable, any desirable material may be added to the pool of slag before tapping. For example, limestone or feldspar .are substances which may be -to cause such slag to solidify in the openings.

Lacasse added, although of course I do not intend to limit myself to those substances alone. rial may be introduced through the usual observation doors, not shown.

As the molten slag accumulates, a pressure is exerted laterally against the walls of the furnace, and this pressure may be taken up by the sliding expansion joint between the oor and the walls. Similarly, the heat from the burning fuel may cause expansion of the walls, and this action may take `place against the opposition of the resilient supports 10. It will be observed that the spout 23 is adapted to move'with the wall upon expansion or contraction of the wall, as just described.

The heat from the pool of molten slag will aid materially in maintaining a high furnace temperature, and the heat is partly carried to the wall tubes by means of the heat conducting tile supported on the tubes, the tubes maintaining the walls cool, so that the high temperature generated by the burning fuel and the pool of slag does not destroy them. The walls are preferably made of the heat conducting tile indicated in Fig. 4,` except at the two openings where a magnesite or other suitable brick may be employed instead of the tile. Such brick are easily replaceable when burned.I out. By this means, a high furnace temperature may be maintained Without damage to the walls, the heat passing through the tile which are of high conductivity, and thence into the water or other medium circulating in the tubes in the walls. Thus, the walls are not only maintained in the presence of a high furnace temperature, but the heat is put to a useful purpose. At the same time, ample provision is made for expansion and contraction of the walls.

It will be noted that the refractory and metal parts of the furnace bottom are arranged to insure that there will be no leaks of slag therethrough. By a leak, I mean a slag iiow at a place other than that at which the slag is intentionally permitted to flow from the furnace, at which place, of course, Aproper provision will be made against damage from such ow. If such a leak were permitted, the stream of liquid slag owing through such a leak, would soon cut the refractory and even the metal parts, by dissolving and eroding the materials along which the slag iiows. This is not true, however, of casual openings extending only -partially through the oor. The heat from the slag which would ilow into such openings may be conducted away with the floor coolingprovisions described fast-enough In other words, a continuous flow of slag will cut, whereas quiescent slag has little or no effect in this respect.

Similarly, the flow of -uid slag down the side walls of the furnace would soon cut these walls,v

were it not for the cooling of these walls by the tubes, which keeps the wall surfaces below the temperature necessary to cause the materials thereof to enter into solution in the slag. This is aided by any layer of solidified or semi-solidified slag which may adhere to such surfaces.

'In the construction described, the-slag from the side walls flows out on the furnace oor, where it joins the slag deposited directly on the oor from the combustion space to form a fluid mass. The joint between the sides of the floor and the side walls is kept tight enough to insure that the slag will not leak through at this point. the angle iron connected to the lower part of each wall, on which plate 18 rests, forming an effective seal for this purpose. By carrying the water tubes well below the top of the floor, protection of all parts of the wall which may be contacted with fluid slag is insured.

The maintenance of the furnace floor' in a relatively cool condition by supplying cooling air in contact therewith cools the lower layer of slag on the floor and renders that portion ofthe slag when the furnace is used in connection with a boiler, there may be lay-over periods during which the combustion rate may be so low that there will not be a suilioientlyhigh furnace'temperature to maintain the slag on the floor molten. As soon as the combustion rate is increased, however, to put the boilerinto full operation, the increased temperature of the furnace will first put the upper part of the accumulated slag into a condition in which it may flow from the furnace. Therefore, when I Adescribe the slag as being maintained in a molten condition, I do vnot intend that it'must be in such condition at all times, but only at such times as the furnace is in normal operation.

Moreover, it is to be understood that, even when the slag is flowing through the tap hole 22 or other outlet opening, there is a pool of slag maintained, even if such opening is never closed, because 'the molten slag flowing over-the floor will keep a layer of molten slag on the floor to prevent any-hardened layer on the top of the iloor from melting, which would permit the floor to be "cu by the owing slag. Where the slag is tapped intermittently, as in my preferred form, this protection is insured by locating the bottom of the said chamber having a substantially horizontal slag receiving floor and side walls held in contact with the sides of the floor and arranged to prevent slag leaking therebetween, and vertical water tubes in said side walls and extending below the top of said floor, the faces of said side walls being formed of heat conducting blocks attached to and i in close thermal contact withsaid tubes, some of said blocks contacting with the sides of said floor,

s aid chamber having an opening through which molten slag may flow and said burner being constructed to impart suilicient heat to slag on said floor vto maintain at least its surfacev in a fluid condition. a

3. In a furnace, a combustion chamber, a burner to burn a slag-forming fuel in said chamber,

said chamber having a substantially horizontal slag receiving floor and side walls held in contact with the sides of the iloor'and arranged tov prevent slag leaking therebetween, and vertical water tubes in said side walls and extending below the top of said floor, said chamber having an opening through which molten slag may flow and said burner being constructed to impart su'flicient heat to slag on said oor to maintain at least its surface in a fluid condition, said floor having a relatively thick. layer of ceramic material and a'metal supporting plate therefor.

4. In a furnace, a combustion chamber, a burner to burn a slag-forming fuel in said chamber, saidl chamber having a substantially horizontal slag receiving floor and side' walls held in contact with the sides of the floor and arranged toprevent slag leaking therebetween, .and vertical water tubes in said side walls and extending below the top .of said floor, said chamber having an opening through which molten slag may ow and said burner being constructed to impart sufli cientheat to slag on said oor to maintain at least its surface in a fluid condition, said floor having a relatively thick layer of ceramic material and a metal supporting plate therefor, said floor having a space beneath said plate, whereby heat therefrom may be conducted slowly away.

5,'In a furnace, means for burning a slagforming fuel, a floor constructed to support a pool of molten slag, water cooled walls contacting with the edges of said floor, and means permitting relative horizontal and vertical movement between said walls and said floor, in combination with a spout coacting with a slagtap opening in one of said walls above the level of said oor and movable therewith upon movement of said wall.

6. In a furnace, means for burning a slag-forming fuel, a floor constructed to supporta pool .l

of molten slag, water cooled walls surrounding said floor, and resilient means supporting said walls independently of said floor, in combination with a spout associated with an opening in one of said Walls and adapted to move therewith upon expansion or contraction of the wall.

7. In a furnace; means for burning a slag-forming fuel, water cooled walls, and a floor having a refractory covering, said floor being constructed to support a pool of molten slag, in combination with means for sealing the joint between the water cooled walls and floor.

8. In a boiler furnace, means for burning a slag-forming fuel, water vcooled walls, and a floor constructed to support a pool of molten slag, said floor having a support independent of the walls Aand movable relatively thereto; in combination with means forming a seal between said walls and said floor, said means preventing passage of slag between said floor and s'aid walls upon relative movement between said walls and said floor, substantially as described.

9,. In a furnace, means for burning a slag-- forming fuel; a floor constructed to support a pool of molten slag, water cooled walls surrounding said floor, and resilient means supporting said, walls independently of said floor, in combination,

with a spout associated with an -opening above the floor in one of said walls and adapted to move therewith upon expansion orcontraction of the wall, said walls being constructed and arranged so that slag may drain from said'walls to said floor.

10. In combination, a furnace, water circulating tubes inthe walls thereof, means for burning fuelin said furnace, means for maintaining a pool of molten materialwithin thefurnace, means from the molten pool to the water circulating tubes in the walls, and means for introducing an for applying the heat from the burning fuel and independent cooling iiuid beneath the oor of said furnace to aid in cooling the same.

11. A furnace comprising walls and a floor, water cooling means forI the walls only, said door being constructedto support a pool of molten slag, and means for projecting a slag-forming fuel substantially horizontally close to the floor.

12. A furnace comprising walls and a door, water cooling means for the walls only, said floor being constructed to support a pool of molten slag, and a turbulent burner of high capacity arranged to project a slag-forming fuel substantially horizontally close to the floor.

13. In a furnace, a combustion chamber, a burner to burn a slag-forming fuel in said chamber, said chamber having a substantially horizontal slag receiving :door and side walls held in contact with the sides of the iioor and arranged toprevent slag leakage therebetween, and vertical water tubes in said side walls extending below the top of said floor, said chamber having an opening through which molten slag may flow, and said burner being constructed to impart sufficient heat to slag onv said oor to maintain at least its surface in uid condition, said floor having a relatively thick layer of refractory material and a metal supportingplate therefor, said floor also having space beneath said plate whereby heat therefrom may be conducted away.

14. A boiler furnace, a floor therefor having metal supporting parts andv a solid protective layer arranged to support a pool of moltenslag, means for fluid cooling said metal oor parts, means for feeding nely-divided slag-forming fuel and air into the furnace and arranged to maintain a pool of molten slag overlying substantially all the solid protective layer, said furnace having a slag tap-hole, side walls adjacent to theslag pool, all of said side walls having metal conduits, and connections for circulating cooling liquid through said metal conduits.

15. A boiler furnace, a oor therefor having metal supporting parts, blocks carried by the metal supporting parts and forming a solid protective layer arranged to support a pool of molten slag, means for fluid cooling said metal oor parts, means for feeding4 finely-divided slag-forming fuel and air into the furnace and arranged to maintain a pool of molten slag overlying substantially all the solid protective layer, said furnace having a slag tap-hole, side walls adjacent to the slag pool, all of said side walls having metal conduits, and connections for circulating cooling liquid through said metal conduits.-

16. A boiler furnace, a oor therefor having metal supporting parts and a solid protective layer arranged to support a pool of molten slag,

means for iluid cooling said metal oor parts, v

means for feeding nely-divided slag-forming fuel and air into the furnace and arranged to maintain a pool of molten slag overlying substantially all the solid protective layer, said furnace having a slag tap-hole, side walls adjacent to the slag pool, all of said side walls having metal conduits. forming spaced water tubes in said side walls and closure means for closing the spaces between said tubes andin thermal contact therewith, and connections for circulating cooling uid through said metal conduits.

17. A boiler furnace, a oor therefor having metal supporting parts and a solid protective layer arranged to support a pool of molten slag, means for fluid cooling said metal floor parts, means for feeding finely-divided slag-forming fuel and air into the furnace and arranged to maintain a pool of molten slag overlying substantially all the solid protective layer, said furnace having a slag taphole, side walls adjacent to the slag pool, all of said side walls having metal conduits forming spaced water tubes in said side walls and closure means for closing the spaces between said tubes, said closure means having metallic parts in thermal contact with said tubes and refractory on said metallic parts, and connections for circulating cooling liquid through said metal conduits.

18. A boiler furnace, a :door therefor having metal supporting parts and a solid protective layer arranged to support Aa pool of molten slag, means for fluid cooling said metal floor parts, means for feeding finely-divided slag-forming fuel and air into the furnace and arranged to maintain a pool of molten slag overlying substantially all the solid protective layer, said furnace having a slag tap- -hole, side walls adjacent to the slag pool, all of said side walls having metal conduits forming spaced water tubes in said side walls and closure means for closing the spaces between said tubes and in thermal contact therewith, said water tubes being arranged for less cooling in some side wall areas than in others, and connections for circulating cooling liquid through said metal conduits. I

19. In a pulverized fuel fired furnace, the combination of a combustion chamber having a bottom and side walls adjacent to a slag pool on said bottom, all of said side walls having uid cooling tubes and a lining for said tubes constructed and arranged to'retain a pool of molten slag overlying substantially all of said combustion chamber bottom, and means for feeding pulverized fuel and air into said chamber arranged to-produce slag liquefying temperature in said slag pool.

20. A boiler furnace, a :door therefor having metal supporting parts and a solid protective layer arranged to. support a pool of molten slag, means for fluid cooling said metal oor parts, said furnace having a slag tap-hole, side walls adjacent to the slag pool, all of said side walls having metal conduits, a burner between certain of the metal conduits and arranged to maintain a pool of molten slag overlying the solid protective layer -of the oor, and connections for circulating cooling liquid through said metal conduits.

21. A boiler furnace, a oor therefor having metal supporting parts and a solid protective layer arranged to support a pool of molten slag, means for fluid cooling said metal floor parts, said furnace having a slag tap-hole, side walls adjacent to the slag pool, all of said side walls having metal conduits located above the furnace bottom, a burner between certain of the metal conduits and arranged to maintain a pool of molten slag overlying the solid protective layer of the oor, and connections for circulating cooling liquid through said metal conduits.

22. In a steam generator, a furnace having a pulverized fuel burner, a bottom, side walls and an upper gas outlet, a steam generating tube bank arranged to receive heating gases from said out-` ERVIN G. BAILEY.

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