US1198841A - Furnace construction. - Google Patents

Description

J. L. HAND, 1n. FURNACE CONSTRUCTION. APPLICATION nuzo mmzo. I914.

1 1 98,84 1. Patented Sept, 19, 1916. 3 SHEETS-SHEET l.

I T I Jun-v21 New MQM / eff mac JLJYande/n 1. L. HAND, JR. FURNACE CONSTRUCTION. APPLICATION FILED MAR. 20, 1914.

Patented Sept. 19, 1916.

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Patented Sept. 19, 1916.

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M N r mm A 5 8 fl- V U W. 1 0 M k W M/ I JUDSON L. HAN'D, JR., 0F PELHAM, GEORGIA.

FURNACE CONSTRUCTION.

Specification of Letters Patent.

Patented Sept. 19, 1916.

Application filed March 20, 1914. Serial 1%. 826,062.

To all whom it may concern:

Be it known that I, J UDSON L. HAND, J r., a citizen of the United States, residing at Pelham, in the county of Mitchell and State of Georgia, have invented certain new and useful Improvements in Furnace Construction, of which the following is a specification.

The object of the invention is to provide for the relative protection of the rear-end construction of, furnaces, more especially of the continuous or moving grate type, and to provide means of protection of such a character as to conserve and utilize to the maximum extent the heat generated, and to econ omize in the consumption of fuel, while minimizing deterioration due to excessive local heating of particular elements, and fa cilitating the replacement or substitution of burned out elements.

With these objects in view,- the invention consists in the provision of means for inducing the circulation of a cooling agent, consisting of 'a combustion-supporting medium,

adjacent to the exposed surfaces of those elements of the furnace construction which are subjected to the heat and which are least protected by the refuse consisting of ash, etc.,' and minimizing the exposure of said parts to the direct radiant heat from the fire bed, and in utilizing the heat extracted from said furnace elements by returning it to the fire bed under such conditions as' will increase the supply of combustion-supporting medium; and while a preferred embodiment of the construction is illustrated in the accompanying drawing, it will be understood that various changes in the form, proportions and minor details of the construction may be resorted to without departing from the spirit of the invention.

In the drawings,Figure 1 is a general diagrammatic-view in longitudinal section of a boiler furnace embodying the inven- -tion; 2 is a detail sectional view of the inner or rear end portion of the furnace,-

. showing means for conducting the cooling agent, and the relation between the rear end furnace elements and the bridge wall; Fig. 3 is a plan view partly'in section of the dump plate and related parts, showing the means. for conveying the coohng agent;

Fig. 4; is a sectional view on the line H of Fig. 3; Fig. 5 is a. detall sectional view on the line 55 of Fig. 2, to show the sectional construction of the apron members.

As 1s usual in constructions of th s character, the parts are arranged 1n such' a way as 'to prevent the influx of air atthe rear end of the furnace, with the object of minimizing the heat at that portion of the furnace,

and to that end the girders 10 are disposed at such interval attheir lower portions as to provide for a substantially complete closure therebetween, when the dump'plate 11 is in its normal position, as illustrated in Fig. 2,

said girders supporting the aprons 12' which are arched to hold back the unconsumed fuel, while permitting the refuse, consisting of ash, etc., to pass .over into the pit or space between the girders and upon the. dump plate. As in the construction illustrated, the

apron may be pivotally mounted upon the upper edge of the girder and ride atits forward edge or nose upon the endless grate 13, or the same may be spaced and supported slightly above the surface of the grate, but suificiently close to the same to prevent refuse from passing thereunden The fuel may, as suggested in Fig. 1, be supplied by feed hoppers 14, while above the space between the girders is located the usualbridge wall 15, preferably of masonry.

Obviously, the upper portion of the apron (it being understood that the furnace may be constructed with a single grate, or may be.

arranged double, as illustrated in the drawing) will be protected to some extent by the I accumulation of refuse, but in order to protect to the greatest possible extent that portion of the apron and the girder below'the line at which the angle of repose of the refuse will. be tangential to the: apron, the bridge wall is corbeled, so that the projection therefrom lies on or above said line; and in order that the inward or exposed surfaces or walls of the apron, girder and dump plate may be kept at the minimum temperature, there is provided in the construction illustrated means whereby a forced circulation ofcooling agent may be induced. Preferably, thiscooling agent consists' of air, to the end that it may be utilized as (fisgplmbusi tion-su orting agent on being arge into th d fuel'bed, and also preferably the circulation of said cooling agent is induced by steam, and specially steam produced in the boiler of the furnace in question, to the end that the'heat of said steam thus utilized may be returned to the fire bed, and thus restored to the furnace in the interest of economy. In the illustrated embodiment of invention, the girder is provided with a large or major circulating chamber 16 into which the steam pressure induced air or cooling agent is forced and from which it passes through the reduced outlets, such as slots or openings 17, to a reduced or minor passage 18, located closeto the inner or exposed wall of the girder, whereby the rapidity of circulation of the cooling medium in contact with said exposed wall of the girder is vastly increased, with a commensurate increase in its cooling effect. From this restricted or minor passage 18 of the girder, the cooling agent passes through registering ports 19 and 20 into a correspondingly restrictedpassage 21, adjacent the inner or exposed wall of the apron, and around the forward edge of the diaphragm 22, forming one wall of said restricted passage 21, to the point of discharge into the fire bed. In the construction"illustrated, the cooling agent passes around the forward edge of the diaphragm 22 into an enlarged or major passagej 23j'fin the apron and is discharged through ports 24, against the movable grate, to assist incooling the latter, but it will be understood that the essential object of this feature of the construction is to return the cooling agent, after it has performed its function, to the fire bed, primarily to restore to the furnace the heat extracted from the furnace elements, and secondarily, to assist in supplying the furnace with a combustionsupporting' agent. Both of these objects are carried out, under the most favorable circumstances, by utilizing steam as the means of inducing the forced circulation of air through the passages formed in the girder and apron, for the reason that as the jet of steam enters the column of cool air, as for example,vin a Venturi blower, it is partly or wholly-condensed and is carried with the column of air in that condition, so that when this moisture-laden air comes in contact with the heated elements of the furnace, it is re-converted into steam, thereby increasing the heat-absorbing qualities of the cooling agent, and finally is discharged into the fire bed to assist in supporting combustion while restoring to a great extent, if not completely, the heat absorbed in its passage through "the furnace elements which have been cooled.

Similarly, the plate may be provid-j ed with a restricted passage or, conduit 25 for conducting the cooling agent to be suitablydischarged through ports 26, and the bridge wan may, as illustrated, be provided withthe passage 27, for a similar purpose.

In Figs. 3 and 4; and in dotted lines. in Fig. ,2," a conventional form of Venturi blower is illustrated at 28, suitable pipes 29 being employed to convey the blast to the various furnace elements, heretofore described.

An important advantage of the structure disclosed resides in the increased rapidity of movement of the column of cooling agent as it traverses the exposed" portions of the furnace elements, as compared with its motion in traversing the protected or less exposed portions of said elements, the object in providing for this action "being to increase the cooling effect thereof, by bringing a greater portion of the heat-absorbing agent into contact with said exposed surfaces. Moreover, the construction and relative arrangement of the parts, with special refer- {ence to the apron, are such as to provide for replacing them, by the suitable provision of outlets from the fire-box (not shown), when injured, burned out, or otherwise rendered unfit for service, without requiring the extinguishing'of the fire;

It will be understood that while in Fig. 1 there is illustrated a double furnace with the elements set back to back with an intermediate pit or Well for receiving the refuse, two

boilers being located respectively above said furnace members, the same principle of construction can be carried out in a sin-,

gle furnace having a wall or other masonry constructionclosing the rear thereof, but as this is an obvious modification, it 1s not deemed necessary to specifically illustrate the same.

It will also be observed that in order to avoid a large and heavy casting in the construction of the apron, with the consequent possibility of injury either to the apron or to the grate by reason of the weight thereof, it is preferable to construct the apron as illustrated in Fig. 4, as embodying a pl rality of apron elements capable of relative independent movement in riding over the grate or obstructions on the grate, and respectively supplied with the cooling agent from the trunk afforded by the hollow girder,

Moreover, these separate or independently movable apron elements are preferably of sectional construction,v as indicated in Fig. 4, and more particularly in detail sections, Fig. 5, wherein said sections 12 and 12 are secured together by means of transverse bolts 30, of which the heads and nuts are protected respectively by flanges 31 on the apron sections.

It will also be noted that while means have been shown and described for introducing a moisture-laden cooling agent to the furnace elements, it is intended to reserve the right to modify the same by using dry cooling agencies where the conditions necessitate or suggest the same.

7 What is-claimed as new is:

1. A furnace comprising means for suping a high velocity of the contents for cooling purposes, and the larger passage producing a low velocity to enable the contents to be heated to aid combustion, one of said passages delivering into the other.

2. A furnace comprising means for supporting a bed of fuel, and an element having its forward edge resting upon said means and be1ngsupported at its opposlte edge and having one side exposed to the heat of said fuel, said. element having reverse passages therein extending toward and from said forward edge and being of unequal capacity, the smaller passage producing a high velocity of the contents for cooling purposes, and the larger passage producing a low velocity to enable the con-- tents to be heated to aid combustion, one of said passages delivering into the other, said element also having an outlet whereby one passage can deliver the contents thereof to said fuel. a

3. A furnace having a moving grate and a hollow apron at the rear of said grate, said apron having its forward edge resting upon said grate, said apron having ,one side exposed to the heat of the fuel upon the grate and having an internal passage of relatively restricted dimensions extending along said side toward the front of the same, and having a second passage of rela tively larger dimensions extending in the opposite direction, the-first passage producng a high velocity of the contents for cooling purposes, and the second passage producing a lower velocity of the contents to enable the same tobe heated to aid combastion, said passages communicating adjacent the front of the apron, whereby the V first passage delivers into the second.

4. A furnace having a moving grate and a. hollow apron at the rear of said grate, sald apron havlng v1ts forward edge resting upon said grate, said apron havingone side exposed to the heat of the fuelupon the grate and having an internal passage of relatively restricted dimensions extending along said side toward the front of the same, and having a second passage of relatively larger dimensions extending in the opposite direction, the first passage producing a high velocity of the contents for cooling purposes, and the second passage producing a lower velocity of the contents to enable the same to be heated to aid combustion, said passages communicating adjacent the front .of the apron, whereby the first passage delivers into the second, said second passage having an outlet adjacent the rear of the apron, whereby the contents of said second passage can be delivered to said fuel.

A furnace comprising means for supporting fuel, a girder at one end thereof, means for discharging from said supporting means over and beyond the girder, said girder having an internal passage of relatively restricted dimensions extending on the exposed side and having a second passage communicating therewith, and extending in the opposite direction, said second passage being of relatively enlarged dimen-' sions, and means for delivering a cooling agent to said second passage, the first passage producing a relatively high velocity of said cooling agent for cooling purposes. Y} 6. A furnace having means for supporting fuel thereon, and containing a girder, said girder having reverse passages therein, ex:- tending between its lateral edges, said passages being of unequal capacity and the smaller passage being'adapted to produce a relatively high velocity of the contents forcooling purposes, one of said passages delivering into the other and said other passage also having an outlet from said girder,

and means for bridging the supporting means and girder.

7. A furnace having a dumping plate,-

members extending along the same and forming-side Walls therefor, said dumping plate; having achamber beneath the same with an outlet atone end and means for delivering acoolin agent'to the opposite end,

said .members aving, passages extending along their exposed faces, the passages in each of said members being of unequal capacity, and the smaller passage being adapted to produce a high velocity of the contents for cooling purposes, and having woutlets adjacent their upper edges and means for delivering cooling agent to said passages.

---8. A furnace of the moving grate type having a loosely supported hollow apron provided with passages, and means for producing a circulation of a cooling agent therethrough, the circulation adjacent to the fireexposed surfaces of said apron being at a greater velocity for cooling purposes, and the circulation adjacent to the less exposed surfaces, being at a smaller velocity for the purpose of heating and aiding combustion.

9. A furnace of the moving grate type having a loosely supported hollow apron provided with commumcating passages, and means for producing a forced circulation of a cooling agentwtlierethrough, the velocity of such circulation being increased adjacent to the exposed surfaces of said apron, for cooling purposes and decreased inthe remainder' of, said passages for the purpose of heating and aiding combustion.

' 10-. A furnaceof the moving grate type having a hollow apron provided with com municating passages for conveying currents of cooling agents in reversed directions, an

apron-supporting glrder having a passage in communicationwith a passage of said apron, and means for inducing the circulation of a" cooling agent in the girder, the passage in the girder and one of the passages in the apron producing a high velocity of said agent for cooling purposes, and the other passage in the apron producing a lower velocity for the purpose of heating and aiding combustion.

11. A furnace of the moving grate type having-a hollow apron'provided with com 'municating passages for conveying reversed currents of a pooling agent, an apron-supporting girder having communicating passages, one of which is in communication with a passage of said apron, said passage in the girder and the last named passage in the apron being for producing a high velocity of the contents for cooling purposes and the remaining passages in the apron producing a lower velocity of the contents for the purpose of heating and aiding conibustion, and means for inducing circulation of a cooling agent in said passages;

.12. A furnace of the moving grate type having a hollow apron provided with communicating passagesv for conveying reversed currents of'a cooling agent, an apron-sup.

porting girder having communicating passages, one of which is in communication with a passage of said apron, and means for inducing circulation of a cooling agent in said passages,'one of the passages of each of said elements being located parallel with the fireexposed surfaces thereof, the said last named passages being for producing a relatively high velocity of said agent for cooling purposes, and the remaining passages in the apron being for producing a lower velocity for the purpose of heating and aiding combustion.

13. A furnace of the moving grate type having a hollow apron provided with com municating passages for conveying reversed currents of a cooling agent, an apron-supporting girder having communicating passages, one of which is in communication with a passage of said apron, and means for in- 'ducing circulation of a cooling agent in said passages, one of the passages of each of said elements being located parallel with the fireexposed surfaces thereof, and being of less cross sectional area than the other-passage,

said passages of less cross sectional area producing a high velocity of the agent'for for the purpose of-heating and aiding combu'stion.

14:.- A furnace comprising a moving grate, an apron resting thereupon,- a girder sup.- porting said apron, said girder and said apron each having reversely extending passages, the passages in the apron cornmuni cating adjacent the forward end of. the apron and the passages in the girder communicating adjacent the lower part of the girder, means for delivering cooling agent to one of the passages in the girder, one of the passages in'the apron having an opening to discharge said agent below the grate, and the other passages in the girder and the apron being in communication with each other and being of relatively restricted dimensions, said last named passages producing a high velocity of the agent for cooling purposes, and the other passages in the apron for producing a low velocity to heat'the agent to aid combustion.

15. -A furnace comprising means for supporting fuel and a girder adjacent said means, said girder having reverse passages extending between its lateral edges and being of unequal capacity, the smaller passage being adapted to produce a relatively high velocity of the contents for cooling purposes, the larger of said passages delivering into the other passage ,and the smaller passage having an outlet from said girder, and means for bridging the girder and supporting means. 1

16. A furnace comprising means for supporting a bed of fuel thereon, a girder in said furnace and an apron having one side exposed to the heat of said furnace,and supported by said means and said girder, said girder and said apron having communi cating passages to permit the circulation of a cooling agent, said passages producing a high velocity of the agent for coolin purposes I 17. A furnace comprising means for supporting a bed of fuel, a girder and an apron, comprising a plurality of sections, each having one side exposed to the heat of the fuel,

and being supported by said means. and said JUDSON L. HAND, JR.

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