US1962178A

US1962178A - Combustion apparatus

Info

Publication number: US1962178A
Application number: US569343A
Authority: US
Inventors: Donald Archibald
Original assignee: Westinghouse Electric and Manufacturing Co
Current assignee: CBS Corp
Priority date: 1931-10-16
Filing date: 1931-10-16
Publication date: 1934-06-12
Anticipated expiration: 1951-06-12

Description

June 12, 1934.

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WITNESSE S A. DONALD COMBUSTION APPARATUS Filed Oct. 16, 1931 2 Sheets-Sheet l [N VENTOR firecmsnw DONALD.

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ATTORNEY A. DONALD COMBUSTION APPARATUS Filed Oct.

June 12, 1934.

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all a: M A TTORNEY Patented June 12, 1934 PATENT OFFICE COMBUSTION APPARATUS Archibald Donald, Moon-es, Pa'., assignor to West? inghouse Electric & Manufacturing Company,- a corporation of Pennsylvania Application October 16, 1931, Serial No. 569,343

7 Claims. (01. 110-44) My invention relates to combustion apparatus and more particularly to underfeed stokers, and it has for a broad object to provide apparatus of this character which is of improved construction and arrangement and which is highly flexible and efiicient in operation.

Most underfeed stokers, heretofore known to me, comprise an elongated retort or retorts and a grate or tuyere structure disposed at the upper lateral edges of the retort. The fuel bed lies over the retorts and tuyeres with the incandescent portions thereof at the top and over the tuyeres. The green coal is fed upwardly from the retorts into the incandescent portions of the fuel bed. The tuyeres, in addition to supporting portions of the fuel bed, furnish the air necessary for combustion.

As the coal nears the incandescent portions it becomes heated and as a, result, the volatile gases present in the coal are liberated and they pass upwardly through the fuel bed and combine with the air flowing through the tuyeres in regions over the fuel bed to effect combustion thereof. The remaining solid combustible or coke passes onto the tuyeres and there combines with air to complete combustion.

If the fuel bed on an underfeed Stoker exceeds a certain thickness sufficient air cannot pass through to eifect efficient combustion. Furthermore, if the bed becomes too thin the stoker parts become exposed and are very likely to burn out. It is, therefore, apparent that the mechanism for feeding the coal should be so designed and should operate in such a manner as to distribute the coal so as to keep the stoker structure covered and at the same time not feed too much coal to any particular region such as would result in a too thick fuel bed and inefiicient combustion in that region.

Primary feeding mechanism located exteriorly of the furnace is usually provided for forcing the coal into the ,ends of the retorts. Secondary rams reciprocating along the bottom of the retort are usually provided for feeding the coal alongthe bottom of the retort and at the same time upwardly into the fuel bed.

For some time, it has been appreciated by stoker manufacturers that if the secondary rams reciprocate at acute angles to the plane of the fuel bed the coal will be fed both longitudinally of the retort and at the same time upwardly into the active portions of the fuel bed. Practically all underfeed' stokers heretofore known to me, are constructed with the secondary rams -reciprocating at certain angles selected by their proponents as the proper angle to feed the coal.

However, considerable difiiculty has been experienced by the manufacturers, due to the fact that their stokers do not operate properly on all coals. Practically any one of the prior structures will operate properly on coals of a particular character, but difficulty in properly distributing the coals is experienced when operating with other types of coals.

From observation and experiment, I have found that the volatile content of the coal is the principal factor governing its feeding characteristics. I have also found that the size of the angles between the plane of the tuyere structure and the directions of reciprocation of the secondary rams have a definite bearing on the manner of feeding the coal. If the angle is relatively large, the ram produces more of a lifting effect and if the angle is relatively small it produces more of a pushing effect in the longitudinal direction of the retort.

I have also found that if the secondary rams of a stoker are arranged to operate at relatively small angles a coal having a relatively low volatile content can be properly fed, but considerable difficulty is experienced when a high volatile coal is so fed, this difficulty being that the tuyeres cannot be kept properly covered. Also, if the secondary rams of a stoker are arranged to operate at relatively large angles, satisfactory results are produced with a high volatile coal, but it is difficult 35 to feed properly a low volatile coal as the fuel bed becomes too thick and inefficient combustion results. These results follow because of variation in the residual mass after volatilization. With a high volatile coal, there is less mass left after volatilization; and, if 'the secondary rams operate at a relatively large angle, more of a lifting effect is exerted thereby and the tuyeres are kept properly covered. Onthe contrary, with a low volatile coal and with more residual solids left 9s after volatilization, less lifting effect is required to keep the tuyeres properly covered and, there fore, the rams should operate at a relatively small angle. It is, therefore, a further and more specific object of this invention to produce a stoker which is capable of being operated properly with all kinds of coal, and, at the same time, is no more expensive to manufacture than the previous designs of stokers. M

A further object is to provide a simple and effective means for angularly adjusting the secondary rams so as to produce the proper feeding action for any kind of coal.

These and other objects are effected by my 110 invention as will be apparent from the following description and claims taken in connection with the accompanying drawings forming a part of this application in which:

Fig. 1 is a longitudinal vertical sectional View of my invention as applied to the downwardlyinclined multiple-retort type of underfeed stoker;

Fig. 2 is an enlarged fragmentary view of a portion of the structure shown in Fig. 1; and,

Fig. 3 is an enlarged fragmentary sectional view taken on the line III-III of Fig. 2.

According to a preferred embodiment of my invention, I provide a stoker including a retort, a tuyere structure disposed at the upper lateral edges of the retort, a primary feeding mechanism for forcing green coal into one end of the retort, at least one secondary ram disposed at the bottom of the retort and reciprocating at an acute angle to the plane of the tuyere structure, and means providing for angular adjustment of the secondary ram so as to vary the size of the angle between the direction of reciprocation and the plane of the tuyere structure and thereby vary its feeding characteristics.

By reason of this structure, if it is desired to feed a coal having a relatively high volatile content the secondary ram may be adjusted to reciprocate at a relatively large angle to the tuyeres; and, if it is desired to use a low volatile coal, the ram may be changed to reciprocate at a smaller angle. Thus, I have devised a structure which can readily and easily be changed so as to feed properly any coal.

Referring now in detail to the structure illustrated in the accompanying drawings, it is to be observed that I have shown my invention as applied to an underfeed stoker of the downwardlyinclined multiple-retort type. The stoker is indicated in its entirety by the reference numeral 1 and it comprises a plurality of parallel spaced retorts 10 androws of overlapping tuyere blocks 11 disposed between and supported by the upper edges of the retorts.

A primary ram 12 reciprocating within a ram box 13 serves to feed green coal from a hopper 14 into the upper end of each of the retorts. A plurality of reciprocating secondary rams 15, 16, and 17 are arranged within the bottom of each retort, and serve to advance the coal along the retort, and at the same time force the coal upwardly and onto the tuyeres. The rams 15, 16, and 17 are driven from a rod 18, the latter having a variable lost motion connection 19, with the primary ram.

Air for combustion is supplied to the space beneath the tuyeres from a wind box 20. The air flows through the tuyere blocks and combines with the combustible in the coal to produce combustion in a manner well understood by those skilled in the art.

Each retort comprises a pair of spaced parallel supporting angle irons 21 and a pair of side walls 22 supported and secured to the upright legs of the angle irons. The secondary rams 15, 16, and 17 are disposed between the side walls 22 and are slidably supported by guide plates also disposed between the side walls; the ram 15 being supported at its forward and rearward ends respectively, by guide plates 23 and 24, the ram 16 being supported in a like manner by

guide plates

25 and 26, and the ram 17 by guide plates 27 and 28.

As will be observed, the secondary rams reciprocate in directions which are at acute angles to the general plane of the tuyere rows. As before stated, the reason for this is to provide both the lifting eifect to the coal and the pushing effect in the direction of extent of the retort.

Each of the

guide plates

23, 24, 25, 26, 2'7, and 28 is pivotally supported at the sides thereof by bearings 29 which are in turn bolted to the lateral web of a supporting angle iron 21. (See Figs. 2 and 3). Each guide is also supported by a pair of bolts 30 which are longitudinally spaced from the bearing blocks 29. The bolts 30 are hinged at their upper ends to their respective guide plates and are secured at their lower ends by

nuts

31 and 32 to the lateral web of the supporting angle iron. The lower ends of the bolts 30 extend through openings in the Web and the

nuts

31 and 32 are screwed to the bolt 30 at opposite sides of the Web and thereby serve to firmly secure the bolt and web. The angular position of each guide plate may be readily changed by a simple manipulation of the

nuts

31 and 32. Obviously, as the guide plates support the secondary rams, angular adjustment of the guide plates results in an angular adjustment of the secondary ram supported thereby.

It is to be observed that the

guide plates

23 and 25 are divided midway their length into two pieces, the forward pieces being firmly secured by the bearing blocks 29 and bolts 30 and the rearward piece being hinged to the forward piece and resting at its rear end on the top surface of the secondary ram. The reason for this construction is to prevent clearance between the top of the ram and the guide plate and thereby prevent sifting of the coal into the air chamber. The hinged rear ends perform this function irrespective of the angular position of the forward ends.

While I have shown my invention in but one form, it will be obvious to those skilled in the art that it is not so limited but is susceptible of various changes and modifications without departing from the spirit thereof, and I desire, therefore, that only such limitations shall be placed thereupon as are imposed by the prior art or as are specifically set forth in the appended claims.

What I claim is:

1. In underfeed stoker apparatus, the combination of an elongated trough or retort; air emitting grate structure at the upper lateral edges of the retort; primary feeding means for forcing solid fuel into one end of the retort; secondary feeding means reciprocating within the retort and at an angle to the longitudinal center line of the retort so as to force the fuel both longitudinally of the retort and upwardly onto 'the grate structure; and means for varying the angle with respect to said center line at which the secondary feeding mechanism re iprocates so as to vary the fuel feeding characteristics thereof.

2. In underfeed stoker apparatus, the combination of an elongated trough or retort; air emitting grate structure at the upper lateral edges of the retort; primary feeding means for forcing solid'fuel into one end of the retort; at least one secondary ram disposed Within the retort; supporting means for the secondary ram and providing for reciprocatory movement of said ram in a direction which is at an angle to the longitudinal center line of the retort so as to force the fuel both longitudinally of the retort and also upwardly over the sides thereof; and means I nation of an elongated trough or retort; air emitting grate structure at the upper lateral edges of the retort; primary feeding means for forcing solid fuel into one end of the retort; a plurality of secondary rams disposed within the retort; guiding and supporting means for the rams and providing for reciprocatory movement thereof in directions which are at angles to the longitudinal center line of the retort so as to force the fuel both longitudinally of the retort and upwardly over the sides thereof and onto the grate structure; and adjusting means for the guiding and supporting means whereby the angle with respect to said center line at which each ram reciprocates may be varied so as tochange the fuel feeding characteristics thereof.

4. In underfeed stoker apparatus, the combination with alternately arranged retorts and rows of tuyeres inclined downwardly from the fuel receiving end and primary feeding mechanism for forcing solid fuel into the fuel receiving end of the retorts; of reciprocatory secondary feeding mechanism disposed within each of the retorts and operating at acute angles with respect to the longitudinal center lines of their respective retorts for feeding the fuel both longitudinally of the retorts and upwardly and out onto the tuyere rows; and means providing for varying the angles with respect to said center lines at which the secondary feeding mechanisms operate so as to change the fuel feeding characteristics thereof to suit different fuels.

5. In underfeed stoker apparatus, the combination with alternately arranged retorts and rows of tuyeres inclined downwardly from the fuel receiving end and primary feeding mechanism for forcing solid fuel into the fuel receiving end of the retorts; of at least one secondary ram disposed within each of the retorts; means for supporting each of the rams so as to provide for reciprocatory movement thereof at an acute angle to the longitudinal center line of its respective retort; and means for adjusting the supporting means so as to vary the acute angle with respect to said center line of the retort at which the ram reciprocates.

6. In underfeed stoker apparatus, the combination with alternately arranged retorts and rows of tuyeres inclined downwardly from the fuel receiving end and primary feeding mechanism for forcing solid fuel into the fuel receiving end of the retorts; of a plurality of secondary rams disposed within each of'the retorts; supporting means for each of the rams and providing for reciprocatory movement of the latter at acute angles to the longitudinal center line of their respective retorts; and means for adjusting the supporting means so as to vary the acute angles at which the rams reciprocate.

7. In underfeed stoker apparatus, the combination with alternately arranged retorts and rows of tuyeres inclined downwardly from the fuel receiving end and primary feeding mechanism 100 for forcing solid fuel into the fuel receiving end of the retorts; of a plurality of secondary rams disposed within each of the retorts; supporting means for each of the rams and providing for reciprocatory movement of the latter at acute 105 angles to the longitudinal center lines of their respective retorts; and means providing for the adjustment of the supporting means for each of the rams so as to vary the acute angle of reciprocation of each of the rams with respect to the 110 others.

ARCHIBALD DONALD.