US2666403A - Corncob burner - Google Patents

Description

Jan. 19, 1954 w; POL 2,666,403

CORNCOB BURNER Filed July 13, 1951 2 Sheets-Sheet l INVENTOR WALTER C. Q -K BY MW A WORNEYS Jan. 19, 1954 w, c, POLK 2,666,403

CORNCOB BURNER Filed July 13, 1951 2 Sheets-Sheet 2 LO '1 Q5 8 Fig.2

INVENTOR WALTER C. PoLK Patented Jan. 19, 1954 2,666,403 CORNCOB BURNER Walter 0. Polk, Fort Branch, Ind. Application July 13, 1951, Serial No. 236,580

2 Claims- (Cl. 110- 18) This invention relates to improvements in forced draft incinerators for waste materiaLand more particularly to an improved corn cob burner, the primary object of the invention being to provide a more practical and efficient device of this kind which lasts longer than conventional incinerators of this type,'is easier and less expensive to operate, substantially eliminates smoke and soot discharge, produces substantial- 1y less ash and residue to be cleaned out, and which can be constructed more quickly and with less expense for materials and labor.

Another important object of the invention is to provide an incinerator of the above-indicated character which produces more rapid and com- Dlete combustion .of the material being incinerated at substantially lower than usual wall temperature through provision for a cooling air blanket 'indrawn from the outside through wall openings and rising along the interior wall surfaces by reason or" the forced draft tuyere grate arrangement provided and by the natural rise of heated air in the interior of the incinerator due to combustion. l

A further important object of the invention is to provide a hollow, vertical, open-top, cylindrical incinerator of the character indicated above, wherein the forced draft burner tuyere grate is located at the center of the incinerator,

away from the walls thereof, and provision is made for supplying the material tobe incinerated to the center of the incinerator immediately above the grate in an arrangement such that the material is burned almost immediately and the burned material is deposited on the floor of the incinerator in an easily removable slag form in a circle around and concentrically spaced from the grate, due to discharge of combustion air by the grate in both upward and lateraldirections.

Other important objects and advantageous fea-,

Figure 5 is a fragmentary, transverse, vertical section taken on the line 5-5 of Figure 2.

Referring in detail to the drawings, wherein like numerals designate 'lze parts throughout the several views, the illustrated corn cob incinorator comprises a fireproof housing l, cylindrical in shape, its diameter and height to vary with the burning capacity required, comprising a poured reinforced concrete outer wall a fire brick liner 9, with asbestos mortar insulation iii between the brick and concrete, and with a screen I! made of No. 9 galvanized wire in tension covered with small galvanised wire cloth l2 overthe top to arrest sparks arising as a result of both natural and forced drafts, and designed principally for the safe and effici nt burning of corn cobs at handling and shipping points. She forced draft is applied in the center of the housing 7 at ground line 63 by a blower is located outside the housing, through a duct id installed below the dirt floor it of the housing, ex-

hausting through a cast tuyere grate ll, causing better combustion and more rapid combustion. Air is also drawn by the effects of the natural and forced drafts through vertically spaced rows of holes I8 in the walls, which rises around the interior surfaces of the walls and reduces the temperature against the walls. Cobs to be incinerated are supplied through a declining spout ill in an opening Zil in the wall arranged to deposit the cobs near the center of the housing and over the tuyere grate ll. At least one of the vertically spaced rows of openings 58 is disposed above the level at which the lower end of the spout enters the housing, and at least one other such row is disposed below this level and between it and the top of the grate i l.

The concrete outer wall 8 is preferably only six inches thick, and the fire brick liner 9 is tures of the invention will be apparent from the following description and the accompanying drawings, whereinior present purposes of i1lustration only, a specific embodiment of tion is set forth in detail.

In the drawings:

Figure 1 is a side elevation, partly broken away and partly in vertical section, to show interior structure:

Figure 2 is an enlarged, fragmentary, top plan v1ew;

Figure 3 is a fragmentary, horizontal section taken on the line 33 of Figure 1;

Figure 4' is a horizontal section taken on the line 4-4 of Figure 1; and I the invenpreferably only four and one-half inches thick, with'one-half inch of asbestos mortar It between the concrete and brick, making a total wail thickness of eleven inches. This compares with the general practice of having walls 32 1 inches thick at the bottom. Some of the advantages of this reduction in wall thickness are lower first cost both of materials and labor, and better radiation of heat, thus reducing the high internal wall temperature which otherwise causes the walls to crack.

The tuyre grate H has a series of holes 21 in its horizontal top 22 for vertical discharge of air and is positioned above the floor I 5, and has side openings 23 providing for horizontal discharge of air. This delivery of oxygen will cause more perfect and more rapid combustion and also cause the "hot spot of the fire to be in the center of the housing away from the walls. This offers these advantages over the present system of burning cobs. The hot spot is at the center of the housing, while in the conventional type it occurs at the walls, and this excessive heat at the walls damages them, even getting so hot that it will melt the fire brick. Also the combustion is more nearly perfect, reducing the amount of ashes approximately 90 per cent, and burning these ashes into a hard clinker. This clinker forms around the tuyere grate ll without touching it, because of the lateral air blast blowing the molten material away from the grate ll. This clinker resembles the crater of a volcano, attaining a thickness of about 12 inches and a diameter of approximately five feet in three full days of burning. It is a very hard, glassy mass, easily broken up for removal. This reduction in ashes is advantageous because the burner does not have to be cleaned of ashes or residue so often, and each days burning starts with practically a clean burner. The above-described forced draft also makes the combustion more rapid and burns the cobs practically as fast as they are supplied to the incinerator, thus avoidng any large accumulation of cobs in the incinerator. Another benefit of the more nearly perfect combustion thus attained is the elimination of practically all smoke and obnoxious gases which otherwise result from the slow imperfect combustion in the conventional incinerators. This is a very important advantage, especially in cities having smoke ordinances with smoke spotters on the job. The blower forcing in a supply of fresh cool air also keeps the tuyere grate at an outside air temperature and prevents it from burning out,

The location of the forced draft in the center of the housing '5, together with the natural heat draft, creates a siphon jet action which draws cool air into the interior of the housing 7 through the holes 15 in the wall. This cool air rises so as to form a curtain of cool air near the wall and diminishes the heat on the walls, thus prolonging the life of the housing i. type of incinerators, the hot air from the hot spots around the wall rises along the wall and heats it, causing the lining to expand and exert a pressure against the outer wall, causing it to crack and even in some instances bursts the steel bands placed around the housing at different levels.

The insulating liner it, formed preferably of one-half inch of asbestos mortar, located between the brick liner 9 and the outside concrete wall 8, is provided to insulate the heat from the concrete wall 8, and to provide a cushion for the fire brick liners 9 to expand into, when heated, thereby diminishing the outward pressure on the concrete wall 8.

The preferably e k-inch thick fire brick liner 9 is formed of bricks laid in a continuous spiral from the bottom to the top, with no mortar in the cross joints, the fire bricks to have only one side dipped in a fluid fire clay mortar at time of placing in the wall. This contrasts with the usual practice of having fire brick liners ranging from 18 inches thick at the base to nine inches thick at the top, with resultant saving in much of the material and labor costs.

In the conventional cob incinerator the air for combustion is drawn through holes in the wall near the bottom. This causes slow combustion at the start and allows excessive quantities of cobs to accumulate in the incinerator, which in time, after burning well, make a very hot fire pro- In the conventional ducing an excessive amount of heat in the housing, due to the quantity of cobs burning. Because of the location of these holes, the hottest spots are at the holes where the oxygen supply is greatest. This is a great detriment to the housing, since it'applies excessive heat to the walls, causing them to crack, burst and burn out. Also, on account of the poor combustion in this type of burner, excessive amounts of smoke and obnoxious gases are given off, and cross winds blowing through the vent holes above the fire pass out on the opposite side of the burner carrying smoke with them which smokes the walls. In the present invention these faults are eliminated by transferring the hot spot to the center of the housing by means of the blower Hi, duct l5 and tuyere burner grate l1, using the holes it in th walls merely to supply cool air to bathe the walls and keep them cooler. In the drawings only three rows of vent holes are shown which were suiiicient to prevent any smoke on the walls of a test apparatus. Due to the upward rush of heat through the center of the housing drawing air in through the vents It, the outside of the apparatus remains clean. 7

The screen I I on top of the housing is formed by stretching No. 9 galvanized wires 25 from pins 25 placed in the top of the concrete wall while it is being poured. These wires 25 are placed cif center so as to avoid building up at the center of the housing 1. Also, these wires 25 being on a chord of the circle, the tension on the housing wall is nearer an end pull than a cross pull, avoiding a strain that would be produced by a right angle mes-h tension which would cause vertical checks on the outside concrete wall On top of this No. 9 galvanized wire support I lay strips 2! of small mesh galvanized wire cloth if? to arrest sparks from discharging from the top of the housing. The advantages of this type of screen are ease of installation, lower cost both of materials and labor, and being flush with the top of the housing wall makes all air and heat di charge vertically instead of having part of it subject to horizontal air currents through vertical sections of the screen projecting above the housing, as is the case in most conventional burners. Due to the turbulence of the air caused by the cool air rushing in through the outside vents l8 and the amount of air supplied by the blower M blending with the heated air from combustion in the center of the housing, the heat is so reduced when it reaches the screen i l, which is preferably 34 feet above the earth fioor it, that it does not even effect the galvanizing on the wire of the screen II.

A banked dirt fill 28 is placed on the dirt floor l6 around the lower end of the housing wall, except at the location of the clean-out opening which is provided in the housing wall at ground level. Ventilating and cooling holes iii surround the opening 20 through which the charging spout l9 enters the housing 7, the inner end of the spout [9 being flush with the interior surface of the housing wall, this arrangement being provided to prevent fire from traveling up the spout 59.

The shelling of 12,000 bushels of corn produces about 82 tons of cobs, which, when dui rped into a conventional burner in a days run, will sometimes fill such burner approximately half full. Since the-charge burns at first at the top, the complete burning of the charge into the night before a really hot and efficient fire develops, which requires watching. This contrasts with the operation of the present invention,

5 wherein the cobs are burned almost as quickly as they are charged into the burner and do not accumulate to any great extent in the burner.

What is claimed is:

1. man incinerator, a vertical cylindrical hollow housing having a substantially plain cylindrical sidewall and being open at its upper end, a bottom wall closing the lower end of said housing, a tuyere grate mounted on and rising above said bottom wall and concentrically spaced from said sidewall, said grate being provided with side openings and with top openings, means connected to said grate for supplying air under pressure to said grate to discharge air laterally toward the housing sidewall at the lower end of the housing and upwardly in the housing, a declining charging spout having a lower end traversing the housing sidewall and entering the interior of the housing adjacent to the lower end of the housing and on a level above said grate, the housing sidewall being provided with a plurality of horizontal rows of circumferentially spaced outside air intake openings, one of said rows of air intake openings being located on a level between the lower end of the charging spout and said grate, and another row of air intake openings being located on a level immediately above the lower end of the charging spout.

2. In an incinerator, a vertical cylindrical hollow housing having a substantially plain cylindrical side wall and being open at its upper end, a bottom wall closing the lower end of said housing, a tuyre grate mounted on and rising above said bottom wall and concentrically spaced from said sidewall, said grate being provided with side openings and with top openings, means connected to said grate for supplying air under pressure to said grate to discharge air laterally toward the housing sidewall at the lower end of the housing and upwardly in the housing, a declining charging spout havhig a lower end traversing the housing sidewall and entering the interior of the housing adjacent to the lower end of the housing and on a level above said grate, the housing side wall being provided with a plurality of horizontal rows of circumferentially spaced outside air intake openings, one of said rows of air intake openings being located on a level between the lower end of the charging spout and said grate, and another row of air intake openings being located on a level immediately above the lower end of the charging spout, the sidewall of the housing being otherwise imperforate,

WALTER C. POLK.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 198,343 Bryan Dec. 18, 1877 413,905 Blanchard Oct. 29, 1889 711,026 Updike Oct. 14, 1902 880,442 Colq-houn Feb. 25, 1908 1,019,837 Revell Mar. 12, 1912 1,303,108 Oehmen May 6, 1919 1,462,720 Rees July 24, 1923 1,494,039 Thomas May 13, 1924 1,496,900 Mitchell June 10, 1924 1,520,539 Duckett Dec. 23, 1924 1,553,008 Stoddard Sept, 8, 1925 1,978,602 Sargent Oct. 30, 1934

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