US2353087A - Combustion apparatus - Google Patents

Description

July 4, 1944. I c. SCHOLL ETAL COMBUS T ION APPARATUS Filed Nov. 12, 1940- v n I l I l l I 1 l I l I I I I. I. m l n lllll/l/ll/l/l/l/A Patented July 4, 1944 COMBUSTION APPARATUS Clark Scholl and Delmond L. Getz, Springfield,

Ohio, assignors ing Company, of Ohio to The Steel Products Engineer- Springfield, Ohio, a corporation Application November 12, 1940, Serial No. 365,168

' (c1. na -4.5)

6 Claims.

This invention relates to combustion apparatus and more particularly to retorts for the burning of solid fuel.

It is a principal object of the invention to provide a construction of retort for use in the buming of solid fuel which provides for the burning thereof in such manner that objectionable formation of coke trees is avoided and a smooth and regulated combustion is secured.

It is a further object to provide a retort into which the solid fuel such as bituminous coal is fed from below in a section of predetermined form and shape such that air supplied thereinto,

which the upward feed of fuel is not materially obstructed, but is arranged to flow smoothly and uniformly into the retort, and in which the tuyeres that supply combustion air are so arranged and located that they are not adversely affected by the heat of the combustion.

Other objects and advantages will be apparent from the following description, the accompanying drawing, and the appended claims.

In the drawing,

Fig. 1 is a plan view of a retort constructed in accordance with the present invention;

a Fig. 2 is a vertical sectional view thereof on the line 2--2 of Fig. 1; and

Fig. 3 is a sectional view on the Fig. 1.

In the combustion of solid fuel, and more particularly in the case of under-feed stokers such as those utilized in the household heating field, a, body of fuel is supplied upwardly into a retort, where air is made available for purposes of combustion. When the fuel, particularly soft or bituminous coal, is supplied in a body of substantial size or thickness, it is sometimes found that an objectionable coking tendency takes place, that is, there is a failure to secure complete combustion throughout the body of the fuel. That portion of the body of fuel which is not properly supplied with combustion air is nevertheless highly heated, and this heating results in distillation and drivline 33 of ing off of the volatile gases of such portion of the fuel body, producing an action equivalent to an actualcoking operation. The fuel in this zone thus forms into a more or less solid mass, and one having substantial structural strength so that it may tend to build up, and form what is referred to in the trade as a coke tree. When the formation reaches such a point that'it can no longer supportitself, it falls and this results in an uneven and undesired supply of fuel, such formation and the resulting inequality of burning being more objectionable during periods of moderate temperature where only infrequent or intermittent operation of the furnace is required. This results in unnecessary supply of fuel under conditime not regulated by the normal furnace controls, reducing the efficiency and effectiveness of the combustion operation.

In accordance with the present invention, a construction of retort is provided which substantially avoids or eliminates objectionable formation of coke deposits so that proper and regulated operation of the stoker may be secured under both high and low rate conditions. In accordance with this invention the body of fuel supplied into the combustion zone is regulated to havea predetermined form and shape such that its sec- .tion is relatively thin. Combustion air is then supplied to the section of the fuel, and made effective upon both sides thereof, the relation between the fuel body and the supply of combustion air being such that the air is made effective from the two sides of the body of fuel to secure substantially complete combustion through the entire section thereof. Preferably the fuel is fed into the retort by a feeder which produces feed impulses such as to cause agitation of the body of fuel tending to assist in the breaking up thereof, In this way the entire body of fuel is actually consumed and this objectionable coking tendency in the interior part of a body of fuel which is not properly supplied with combustion air, is avoided. Further the arrangement is such that the tuyeres through which the air is introduced are properly supported and protected against excess temperature conditions such as might result in the fusing or burning away thereof; and a properly balanced and well regulated supply of fuel is afforded without materially increasing the obstruction to the fuel feed.

, Referring to the drawing which discloses a preferred embodiment of the invention, the retort structure is indicated generally at 10, and includes a supporting casing or chamber II which is supplied with combustion air under pressure from a suitable source. This casing, thus forms a plenum chamber from which air is supplied through openings in the tuyres into the combustion zone.

The fuel supply conduit is shown at l2 leading from a. suitable source of fuel supply, and having a feed worm I3 therein suitably driven. As an example of a satisfactory form of drive, that shown in Scholl Patent No. 2,145,943, owned by the assignee of this case, may be used. That drive provides timed feed impulses each of substantially the same magnitude to actually lift the fuel bed and assist in the breaking up of fuel bodies, and with provision for predetermining the length of the intervals between impulses to vary the actual rate of feed.

The conduit I Zopensinto a feedpassage member I preferably formed as a casting, having a forwardly and upwardly curved passage l6 projecting forwardly beyond the end of the feed worm. It is also provided with a forwardly eX- tending top portion I! the lower side of'which is given a generally semi-cylindricalcurvature as shown in Fig. 3 so as to deflectthe upwardly moving body of fuel to either side thereof with a minimum of frictional resistance andwith the avoidance of dead feed zones. This topportion I1 is an integral part of the fuel supply conduit and thus: is in direct heat transfer relation withthe .entire mass thereof. Itterminates-short of the .forward wall l6 leaving an open feed'zone l8 of curved shape. At either side of this. portion I! the walls ofconduitl5 divergequpwardly as shown at I9, leaving atpair of side passages 20,

indirect and .continuous communication :with passage I8, and providing for ,theunrestricted and regulated upward flow of fuel. Flanges 2! are formed at the uppersurfaceofiportions I! and IQ for receivingcooperatingparts of the :tuyeres thereon in interlocked but readilyremovable manner.

As will be apparent from. Fig. 1;. the 'shape .of

the combined passages. l8 and 20 is substantially c-shaped in cross section, and the relative. areas of the several portions. ofthe section areusuitably regulatedso as to provide for substantially uniform flow of thefuel throughout the; entire arcuate extent of the feed passage sothat proper and regulated distribution is obtained into a parts of the combustion Zone.

A plurality of tuyeres '22 are'mounted-on the upper end of the feed passage, being provided with a locking portion 23 received on flanges 2! to be guidedandsupported in proper positioning thereonand providing for individual removal and replacement thereof if necessary. 'Thesetuyeres are so formed that in the assembled form'they constitute a substantially complete ring, sloping outwardly and upwardly, and providing forsupplying combustion air to the fuel in the course of its upward travel, through several series of openings 24 which are in direct'communication with the plenum chamber.

An additional set-of tuyeres is supported upon the section l1, this group comprising a pair of complementary tuyre sections 26 suitably supported upon the member I! was to be in heattra'nsferring relation therewith'throughout their entire length. The forwardendsfl of these ner periphery of the bodyof fuel, the lowermost "such openings preferably being located at a *somewhat lower level than those of the outer series of tuyres 22, and the uppermost'openings being located below the level of the uppermost openings 24. This provides for locatingthe entire tuyeresections 26 at alower -l'evel'*and'thus not'in the "highest heat zone.

From the foregoing it will be seen that this construction provides for introducing into the combustion zone a body of fuel all portions of which are adapted to be properly supplied with combustion air, being of relatively narrow cross section throughout, the section being such that under ordinary combustion conditions, the supply of combustion air from both the outer and inner peripheries would normally result in securing substantially complete combustion throughout the entire section. In this way the combustion is carried forward substantially completely, and the tendency to the formation of coke trees islargely overcome and rendered unobcoke which may tend to form being such that it does not haveinherent structural strength and under the actual conditions of combustion will break down and be consumed. Also the mechanicalagitation afforded by the feeding impulses Lil assists in overcoming the tendency for the fuel to form into such bodies, the mechanical agitation afforded by the feeding stroke being substantially the'same at high feed .as at low feed since the magnitude of the impulses-is not changed.

It will'be further noted that the inwardly projecting tuyres 26 are indirect air and heat-transferring relation with the remainder of the retort Whilethe form of apparatus herein described constitutes a preferred embodimentb'f the invention, it is to be understood that'theinventionis not limited to this precise-form of. apparatus,

::and that: changes may bemade therein without departing-from. the scope .of the invention which is defined inthe appended claims.

What is claimed is:

1. A retort of the'characterdescribed for burning solid-fuel substantially uniformly and-without objectionable formationof coke deposits comprising a fuel feeding passage, means overlying one end of said passage forming a substantially C-shaped combustion zone for receiving and burning the fuel, the combustion Zone being continuousand uninterrupted from one'end 'to the other, a'first group of tuyres around the outer periphery of said c'ombustion'zonefor supplying combustion air into the outersurface of the 1 body of fuel as it'flows upwardly into and through the combustion zone, and another groupof tuyeres projecting toward theinterior of said com- -bustion zone from the opposite side thereof to supplycombustion-air thereto from the opposite side tosecuresubstantially complete combustion of the entire'section of the fuel body, said other group of tuyres being located directly above said end of'said fuel feedingpassage, and means for feeding fuel from beneath said other group of tuyres in the direction toward said first group of tuyeres to supply fuel to the more remote portions of said fuelbodyby'direct upward travel and to -the less remote portions of said fuel body --by deflected upward travel.

"2. A retort-0f the character described for burning solid fuel substantiallyuniformly and without objectionable formationofcoke'deposits comprising a fuel supplyconduit, said conduit having an upwardly curved open" passage at its forward end an'd'having a centrally located forwardly extendingtop portion terminating short of the opposite wall of said passage forming a pair of supply passages at either side thereof in direct communication with said upwardly curved passage, tuyeres mounted around the outer periphery of said passage and upon said forwardly extending portion providing for supplying combustion air to the body of fuel from both sides thereof as it travels upwardly through said retort, and

fuel feed means extending forwardly beneath said top portion for delivering fuel substantially uniformly by direct upward flow to the more remote upwardly curved passage and by laterally deflected flow under said top portion to said less remote side passages.

3. A retort of the character described for burning solid fuel substantially uniformly and withsaid tuyeres being arranged in an outer generally arcuate manner extending from one of said side passages to the other and defining an arcuate retort for supplying combustion air to the outer surface thereof, and additional tuyres located on said forwardly extending portion for supplying combustion air to the body of fuel inwardly of the ends of said arcuate fuel body and cooperating with said first mentioned tuyres for assuring substantially complete combustion of the entire section of the fuel body.

4. A retort of the character described for burning solid fuel substantially uniformly. and without objectionable formation of coke deposits comprising a fuel supply conduit, said conduit having an upwardly curved open passage at its forward end and having a centrally located forwardly extending top portion spaced from the end of said conduit forming a pair of supply passages at either side thereof in direct communication with said upwardly curved passage, a feed worm for feeding fuel through said conduit, said ing solid fuel substantially uniformly and without feed worm extending toward said upwardly curved passage and located directly beneath said top portion to provide for positive upward feed of fuel in a forward direction into said more remote upwardly curved passage and with a deflected flow under said top portion into said side passages, and tuyeres mounted above said top portion and said conduit and arranged in an outer generally circular manner extending from one of said side passages to the other for supplying combustion air to the inner surface of said :body of fuel and to the outer periphery thereof to provide for substantially complete combustion of the entire section of the fuel body.

5. VA retort of the character described for burnobjectionable formation of coke deposits comprising a fuel supply conduit, said conduit having an upwardly curved open passage at its forward end and having a centrally located forwardly extending top portion spaced from said end of the conduit forming a pair of supply passages at either side thereof in direct communication with said upwardly curved passage, means posithe periphery of said passage and on said forwardly extending portion for supplying combustion air to both the inner and outer surface of said body of fuel to secure substantially complete combustion thereof.

6. A retort as recited in claim 3 in which said additional tuyeres are constructed to supply the combustion air at a level below that supplied by said first mentioned tuyeres, said additional tuyres being located out of the highest heat zone.

CLARK SCHOLL. DELMOND L. GETZ.

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