US3362359A - Grease burner - Google Patents

Description

Jan, 9, 1968' E. 1.. KELLS ETAL GREASE BURNER 3 Sheets-Sheet 1 Filed April 1965 Jan. 9, 1968 v E. L. KELLS ETAL 3, I

I 4 GREASE B RNER Filed April 9, 1965 v 5 Sheets-Sheet 2 Jan. 9, 1968 E. L. KELLS ETAL 7 3,362,359

Filed April 9, i965 GREASE BURNER 3 Sheets-Sheet 3 Zzward Z. fife/8 v $1 57 5 Wasfibzzrzz United States Patent Oiiice 3,362,359 Patented Jan. 9, 1968 3,362,359 GREASE BURNER Edward L. Kells, Batavia, and Billy S. Washburn, West Chicago, Ill., assignors, by mesne assignments, to Chicago Bridge dz Iron Company, Chicago, 11]., a corporation of Illinois Filed Apr. 9, 1965, Ser. No. 446fi 13 (Ilaims. (Cl. 110-8) The present invention relates to a burner for disposing of greasy skimmings obtained in the course of the disposal of sewage and the following disclosure thereof is offered for public dissemination upon the grant of a patent therefor.

Sewage includes, depending upon the location, substantial amounts of grease. The disposal of this grease can be a diificult problem. This is discussed in greater detail in patent application No. 312,658, filed Sept. 30, 1963, now abandoned, the disclosure of which is incorporated herein by reference.

The principal object of the present invention is to provide a method of, and an apparatus for, burning waste grease which is relatively simple and foolproof. Embodiments of the present invention can be satisfactorily operated by a relatively untrained employee, having no special knowledge or skills. There are no unusual maintenance problems since the apparatus is relatively simple, with the operating parts being, in the main, standard items of manufacture. At the same time the burning does not create air pollution problems, which is becoming a more and more important factor to the large communities.

Further objects and advantages will become apparent from the following description taken in conjunction with the drawings, in which:

FIGURE 1 is an elevational view showing in vertical section a portion of a building with an embodiment of the present invention installed therein;

FIGURE 2 is a partial vertical section as viewed at line 22 of FIGURE 1;

FIGURE 3 is a horizontal-section as viewed at line 33 of FIGURE 2;

FIGURE 4 is a diagrammatic illustration of the burning action achieved through the use of the present invention;

FIGURE 5 is a partial vertical section of an alternate embodiment; and

FIGURE 6 is a partial vertical section of a second alternate embodiment.

Although the following disclosure offered for public dissemination is detailed to ensure adequacy and aid understanding, this is not intended to prejudice that purpose of a patent which is to cover each new inventive concept therein no matter how others may later disguise it by variations in form or additions or further improvements. The claims at the end hereof are intended as the chief aid toward this purpose; as it is these that meet the requirement of pointing out the parts, improvements or combinations in which the inventive concepts are found.

Furnace construction The furnace is annular in configuration being formed by a cylindrical shell 10, a base 11 and a roof 12. Extending upwardly from roof 12 is a stub chimney 13 which enters into the main chimney 13'. The interior of the furnace has a suitable firebrick lining 14 which, across the base, defines a hearth 15. Insulation (not shown) is provided between the metal shell and the lining 14. The metal shell also defines an intake air plenum 16. Air is delivered to plenum 16 under pressure through a pipe 17 from the discharge of a blower 18. The intake for the blower is defined by a pipe 19.

A plurality of tubes 22 forming nozzles extend through roof 12 from plenum 16. Through tubes 22, air jets are directed at hearth 15 at an angle to the surface of the hearth (FIGURES 2 and 4) all in the same rotational direction and with a component generally tangent to a circle 23 on the hearth (FIGURE 3). Thus, for example, the air jet from one of the tubes 22 traverses a path 24 somewhat as depicted in FIGURES 2 and 3, except that after being reflected from the hearth, the air goes up in a circular pattern about the central body of flame. This positioning of the air jets in the furnace is important to set up a burning configuration as discussed in connection with FIGURE 4. A plurality of tubes 25 extend through stub chimney 13 and are in communication with plenum 16. These tubes 25 likewise are positioned so as to impart a whirling motion to the air and other gases traversing stub chimney 13. As hereinafter described, stub chimney 13 thus forms an afterburner to completely consume the combustible material exiting through the stack. Additional air is introduced into the main chimney 13' through intake pipe 26.

Grease is introduced into the furnace through a distributor formed by conduit 27 having a discharge opening at 28. Conduit 27 has a vertical portion 27a and a horizontal portion 2712. Vertical portion 27a is connected by a slip joint 29 to a feed pipe 30. It is journaled in bearings 31 and has a sprocket 32 afiixed therto. Sprocket 32 is driven by a chain 33 connected to the output sprocket of a speed reducer 34 which, in turn, is driven by a motor 35. Vertical portion 27a of the conduit extends through a sleeve 36 secured to the bottom of the furnace. A cap 37 attached to portion 27a of the conduit prevents material from falling down through between the sleeve and the conduit.

Conduit 27 is formed with a cut out 38 to facilitate cleaning of the conduit should any material become lodged therein. A removable section 39 in one wall of the furnace forms an access door. By stopping the outer end of conduit 27 at a location adjacent removable section 39, it is possible to insert a rod through opening 38 in the conduit to dislodge any accumulated material therein.

A rabble 42 is secured to conduit 27 by chains 43. The rabble drags behind the conduit and pushes accumulated ash toward a discharge pipe 44 extending downwardly through the hearth 15. Sight glasses are mounted in tubes 45 extending through the Wall of the furnace. Rabble 42, chains 43 and conduit 27 are formed of stainless steel.

A blower 46 has its discharge tube 47 extending through the wall 10 of the furnace. A gas feed line 48 enters discharge tube 47 and has a discharge opening or gas burner 49 inside the discharge tube to preheat the furnace to a suitable temperature for burning of the greasy skimmings. Electric ignition means (not shown) is provided for the gas burner.

Material feed The preparation of the greasy skimmings is very important. It is necessary that there not be large pockets of water incorporated into the skimmings. Any such large pockets of water reduce the temperature in the furnace and may even cause a flameout. To prevent this the greasy skimmings are first decanted to eliminate the majority of the water therefrom. The grease along with the remaining water is then homogenized, blended or emulsified so as to thoroughly mix the remaining water with the grease. When so homogenized, the material has the appearance and texture of a dirty mayonnaise.

The apparatus for suitably conditioning and feeding the greasy skimmings is illustrated in FIGURE 1. After decanting, the greasy skimmings are fed by a pump, not shown, through a pipe 50 to the intake of a hammer mill 51 havingabout A" slots. The hammer mill grinds up any solid foreign material that may not have been previously eliminated. In addition, it does a rather effective job of emulsifying the grease and the remaining water. From the hammer mill the skimmings are discharged into a holding tank 52. A propeller type blender in tank 52 is driven by a motor 53. The blender, by its agitation, maintains an emulsion in the holding tank. Should the blender not be operating, the materials in tank 52 again will tend to separate with some decanting of the water therein. A valve 54 communicates with the bottom of tank 52 and is positioned above a drain 55 so that any accumulated water in the bottom of the tank can be drawn off.

Intake pipe 57 of a pump 58 communicates with tank 52 slightly above the bottom thereof. The discharge of pump 558 communicates with feed line 30. It also communicates with a pipe 59 through a valve 60. Pipe 59, in turn, is connected to intake pipe 50. This permits a recirculation of the skimmings through hammer mill 51 to tank 52 when necessary or desirable. Immediately adjacent the furnace, feed pipe 30 'has a T 61 (FIGURE 2) to which is connected a valve 62 and a return line 63. Return pipe 63 communicates with tank 52 adjacent the top thereof as best seen in FIGURE 1.

Operation To start the furnace, it is first preheated by the use of the gas burner 4% and blower 46. After it has been preheated to a suitable temperature (e.g. 15 F.), the feeding of skimmings through conduit 27 is commenced. After the temperature rises to about 1900 F., the gas is turned off but the blower 46 remains running so that no fumes back out through the blower. During the feeding of the skimmings the conduit is rotated, preferably at a speed of about 32 r.p.m. While the speed is not particularly critical, relatively high speeds introduce bearing problems. Also, it has been found that speeds too low to give a dosing frequency of about 6 seconds, i.e. below about 10 r.p.m. in the case of single outlets, do not produce such a distribution of the skimmings as will create an even burning in the furnace. The furnace temperature usually runs between about 2l002300 F., the principal variable being the amount of water in the skimmings. Automatic controls are provided to restart gas burner 49 if the temperature goes below 1900 F. and to shut down the material feed if the temperature goes above about 2300 F.

The general pattern of the flame in the furnace is illustrated in FIGURE 4. Except adjacent the hearth, the flame is confined to a central body of flame which is rotating very rapidly producing a vortex of flame. The air jets from tubes 22 rebound from the hearth in such a fashion that they create an annulus of air rotating about the central body of flame. This has effects which are important to the operation of the furnace. The confining of the combustible gases to a central area results in a very high temperature being achieved. There is a complete destruction of the mercaptans, carbons, etc., which otherwise cause air pollution problems. Sufficient air surrounds and impinges upon this body of flame so that all of the combustible materials will burn. The injected air stirs and aerates the combustible vapors. It also has a protective cooling effect on the hearth and distributor and prevents heavy clinker formation. A further major advantage of the FIGURE 4 type of flame formation is that the walls of the furnace are washed with cool air rather than flame. Thus, the furnace linings have a much greater life than would be the case were they in direct contact with the high temperature body of flame achieved to destroy the air pollution materials.

Due to the rotation of the distributor 27 and the deposit of the skimmings in a ribbon 65 about the periphery of the hearth, the flame arises and burns from all sides of the hearth. In effect there is no wasted hearth space in the furnace. Of course, as the ribbon of skimmings is heated on the hearth, it flows outwardly from the initial point at which it was deposited. The water is promptly boiled off and the grease is vaporized. The grease should be introduced at a rate at which the burning rate is about 280,000 B.t.u.s per cubic foot of furnace volume per hour. The total volume of air introduced should be at a rate in excess of the stoichiometric amount (as related to the amount of combustible material) without being so excessive so as to cool the furnace below about 1800 F. The fact that some of the air is introduced into the afterburner assists in preventing over-cooling of the furnace proper. While the furnace could be other than round in cross section, this would just result in unused corners which would fill up with ash, etc., resulting in a substantially round hearth. Furthermore, it would be more difficult to obtain the whirling air and flame pattern of FIGURE 4 with other than a round furnace.

The afterburner section defined by the short stack portion 13 is important to obtaining complete combustion. In this section additional air is injected into and about the flame pattern to make sure that complete combustion occurs. Additionally, the upwardly movement of the air jets cause them to aspirate gases out of the furnace thus reducing the air pressure in the furnace proper. This results in an easing of the sealing problems about any openings and reduces the possibility of gases, etc., escaping through openings in the furnace proper.

A substantial amount of the ash produced is very fine and will be carried up through the short stack 13. A wet scrubbing or electrostatic precipitator means (not shown) should be provided to remove this fly ash before the combustion products are discharged into the atmosphere. The remaining ash and slag is dragged to discharge conduit 44 by rabble 42.

When the furnace is to be shut down, the feed of material to conduit 27 first is discontinued. When the furnace temperature drops to about 1900 F., gas burner 49 is automatically ignited. This then supplies heat to clean up the hearth 15. Thereafter, motor 35 and burner 49 are shut down.

Alternate forms of grease distribution FIGURE 5 illustrates an alternate form in which the hearth 70 is formed by a horizontal rotating table having a metal bottom 71 with a firebrick cover thereover. Bottom 71 is supported on bearings 72 and is rotated by a shaft 73 secured thereto. An ash opening 74 is provided in the hearth and at one point in its circle of revolution the ash opening is above a disposal pipe 75. A valve plate 76 closes opening 74 except when it is above disposal pipe 75. A feed conduit 77 extends through wall 10 of the furnace. As the hearth 70 rotates, a ribbon 73 of skimmings is deposited on the hearth through the downwardly positioned discharge opening of conduit 77. A rabble 79 is pivotally mounted on a pin 80 and is positioned so that the ash moving along hearth 70 will be pushed into open ing 74 FIGURE 6 illustrates an embodiment similar to FIG- URE 2 except that the distributor is in the form of a slinger which will throw the skimmings by centrifugal force outwardly against wall 10 of the furnace where it slumps into a ribbon 81 at the base of Wall where the wall meets hearth 15. The slinger includes a vertical rotating pipe 82 which substantially corresponds to vertical portion 27a of the distributor of FIGURE 2. A lower horizontal plate 83 is secured to pipe 82. A plurality of radial vanes 84 are fastened to plate 83 and an an upper plate 85 is attached to the vanes. The greasy skimmings are ejected at the top of pipe 82 in the space defined by the inner ends of the vanes 84. The skimmings flow. out through the space between the vanes and are ejected by centrifugal force to fly toward the wall 10 of the furnace. Of course the slinger must be rotated at a sufficiently high speed so as to obtain this centrifugal distribution. As seen in a plan view, plates 83 and 85 would be circular with vanes 84 evenly spaced about the axis of shaft 82 and extending radially outward from'the central space defined by their inner ends.

We claim:

1. A burner for disposing of the grease obtained as skimmings from a sewage disposal plant, said burner including: a furnace comprising a generally cylindrical wall positioned with its cylindrical axis vertical and a hearth at the bottom of said wall; means to continuously deposit a ribbon of grease about said hearth adjacent the cylindrical walls, said means including a rotating distributor conduit having a discharge end adjacent said cylindrical walls from which end said ribbon is extruded and means to rotate the conduit with respect to the furnace; and a device including a plurality of nozzles extending into said furnace and means to introduce air into said nozzles under pressure.

2. A burner for disposing of the grease obtained as skimmings from a sewage disposal plant, said burner including: annular furnace walls formed about a vertical axis; a closed bottom for said walls and including a hearth member; an air jet device to direct air under pressure into said furnace in a plurality of streams, said streams being directed downwardly toward said hearth member at an angle to the hearth member and with a component tangent to a circle on said hearth member; a grease introduction conduit member having a discharge opening immediately above said hearth member from which opening said grease is extruded, said opening being positioned some distance from said axis; one of said members being rotatable about said axis with respect to the other; power means connected to said rotatable member to rotate the same; and pump means connected to said conduit to introduce grease into the conduit to be fed into said furnace through said opening; said members being so arranged that the grease forms a ribbon on said hearth which ribbon is outside of said circle.

3. A grease burner as set forth in claim 2, wherein said hearth member is rotatable.

4. A grease burner as set forth in claim 2, wherein said conduit member is rotatable.

5. A grease burner as set forth in claim 4, wherein said conduit member includes an impeller rotated by said power means at sufiicient speed to centrifugally impel said grease outwardly therefrom.

6. A grease burner as set forth in claim 4, wherein said conduit member has a downwardly discharge opening immediately above said hearth member with the conduit extending straight approximately from said axis to a downwardly turned portion above said opening, said condu'i having a cleanout opening in said downwardly turned portion.

7. A grease burner including: annular furnace walls formed about a vertical axis; a closed bottom for said walls and including a hearth member, said hearth member having an ash opening extending downwardly therethrough; an air jet device to direct air into said furnace in a plurality of streams, said streams being directed downwardly toward said hearth member; a grease introduction conduit member having a discharge opening immediately above said hearth member, said opening being positioned some distance from said axis; one of said members being rotatable about said axis with respect to walls; power means connected to said rotatable member to rotate the same; pump means connected to said conduit to introduce grease into the conduit to be fed into said furnace through said opening; and a rabble mounted on the conduit member and adapted to drag on said hearth member.

8. A burner for disposing of the grease obtained as skimmings from a sewage disposal plant, said burner including: annular furnace walls for-med about a vertical axis; a closed bottom adjoining said walls and including a hearth member; a chimney extending upwardly from said walls, the opening within said chimney being substantially smaller in horizontal cross-section than is the opening within said walls; an air jet device to direct air into said furnace in a plurality of streams, said streams being directed downwardly toward said hearth member, said device also introducing air directly into said chimney in a plurality of jets; a grease introduction conduit member having a discharge opening immediately above said hearth member from which opening said grease is extruded, said opening being positioned some distance from said axis; one of said members being rotatable about said axis with respect to walls; power means connected to said rotatable member to rotate the same; and pump means connected to said conduit to introduce grease into the conduit to be fed into said furnace through said opening.

9. A grease burner including: annular furnace walls formed about a vertical axis; a closed bottom adjoining said walls and including a hearth member; a chimney extending upwardly from said walls, the opening within said chimney being substantially small in horizontal crosssection than is the opening within said walls; an air jet device to direct air into said furnace in a plurality of streams, said streams being directed downwardly toward said hearth member at an angle to the hearth member and having a component tangent to a circle on said hearth member in a given rotational direction, said device also introducing air directly into said chimney in a plurality of jets, said chimney jets being directed upwardly and in said rotational direction; a grease introduction conduit member having a discharge opening above said hearth member and some distance from said axis; one of said members being rotatable about said axis with respect to walls; power means connected to said rotatable member to rotate the same; and pump means connected to said conduit to introduce grease into the conduit to be fed into said furnace through said opening.

10. A grease burner including: annular furnace walls formed about a vertical axis; a closed bottom joining said walls and forming a hearth, said hearth having an ash disposal opening extending downwardly therethrough, a chimney extending upwardly from said walls, the opening within said chimney being substantially smaller in horizontal cross-section than is the opening Within said walls; a grease introduction conduit extending upwardly through said bottom at said axis, outwardly to a point adjacent said walls and then downwardly and terminating in a discharge opening above said hearth, said conduit being rotatable with respect to said bottom; means connected with the conduit externally of said bottom to introduce grease under pressure into said conduit; power means connected to said conduit to rotate said conduit; a rabble connected to said conduit and adapted to drag on said hearth; and an air jet device to direct air into said furnace in a plurality of streams, said device also introducing air directly into said chimney in a plurality of jets, said chimney jets being directed upwardly and in a rotational direction.

11. In the method of burning grease included in a mixture of grease and water obtained from sewage in a furnace having a hearth, the improvement comprising: separating the majority of the water from said grease; blending the remaining water and grease; continuously depositing said grease in a generally circular ribbon on said hearth; and blowing air for combustion in a plurality of spaced jets directed downwardly toward said hearth at an angle thereto and having a component tangent to a circle concentric with and inside of said ribbon.

12. In the method of burning the thick grease obtained as skimmings from a sewage disposal plant in a furnace having a hearth and a chimney about a vertical axis and extending upwardly from the furnace, the improvement comprising: continuously depositing said grease about said hearth in a generally circular ribbon about said axis; blowing combustion air under pressure in a plurality of spaced jets directed downwardly toward said hearth at an angle thereto and in a given rotational direction about said axis whereby a vortex of flame rotating in said given directon is created in said furnace as said grease burns; and blowing air under pressure into said chimney in an upwardly direction and rotationally about said axis in said given direction.

13. In the method of burning the thick grease obtained as skinirnings from a sewage disposal plant in a furnace having a hearth, the improvement comprising: continuously depositing said grease in a generally circular ribbon about said hearth; and blowing combustion air under pressure in a plurality of spaced jets directed toward said hearth at an angle thereto and having a component tangent to a circle concentric with said ribbon, said ribbon of grease being deposited between said circle and the periphcry of the hearth.

References Cited UNITED STATES PATENTS Heath 15 8-4 Thornton 15 84 Arnold 15828 Pecker 1108 McConechy 1 10-8 Peter 15 891 Breese 15 891 Ree d 1 108 Hanley et al. 15 8-4 FREDERICK L. MATTESON, JR., Primary Examiner.

15 H. B. RAMEY, Assistant Examiner.

Patent No. 3,362,359

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION January 9, 1968 Edward L. Kells et a1.

It is certified that error appears in the above identified patent and that said Letters Patent are hereby corrected as show below:

Column 1, lines 18 and 19, cancel "now abandoned,";

line 20, after "reference." insert Patent 3,312,183 issued April 4, 1967 on an application filed June 10, 1965 as a continuation of that application. Column 6, line 19, "small" should read smaller Signed and sealed this 16th day of December 1969.

(SEAL) Attest:

Edward M. Fletcher, Jr.

Attesting Officer Commissioner of Patents WILLIAM E. SCHUYLER, JR.

Claims (1)

1. A BURNER FOR DISPOSING OF THE GREASE OBTAINED AS SKIMMINGS FROM A SEWAGE DISPOSAL PLANT, SAID BURNER INCLUDING: A FURNACE COMPRISING A GENERALLY CYLINDRICAL WALL POSITIONED WITH ITS CYLINDRICAL AXIS VERTICAL AND A HEARTH AT THE BOTTOM OF SAID WALL; MEANS TO CONTINUOUSLY DEPOSIT A RIBBON OF GREASE ABOUT SAID HEARTH ADJACENT THE CYLINDRICAL WALLS, SAID MEANS INCLUDING A ROTATING DISTRIBUTOR CONDUIT HAVING A DISCHARGE END ADJACENT SAID CYLINDRICAL

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