US 3826208 A
The disposal of hydroscopic combustible material, such as scrap wood and bark, needs to be carried on at a temperature of about 600 DEG F. or somewhat lower to prevent flashing off certain volatiles which at or above that temperature level cause the formation of a noxious blue smoke. The system and apparatus is caused to move a large volume of air through a furnace to provide the needed heat for drying the material to a state where it can be consumed by serving as a fuel. The air volume so moved is dust laden, and the apparatus concentrates the dust and particulate material for burning, and effectively mixes the combustible products with cleansed air to produce a source of heat at a controlled temperature level.
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Description (OCR text may contain errors)
United States Patent [1 1 Williams [111 3,826,208 [451 July 30, 1974  inventor: Robert M. Williams, Ladue, Mo.
 Assignee: Williams Patent Crusher and Pulverizer Company, St. Louis, Mo.
 Filed: Aug. 6, 1973  Appl. No.: 385,984
Primary Examiner-Kenneth W. Sprague Attorney, Agent, or FirmGravely, Lieder & Woodruff  ABSTRACT The disposal of hydroscopic combustible material, such as scrap wood and bark, needs to be carried on at a temperature of about 600 F. or somewhat lower to prevent flashing off certain volatiles which at or above that temperature level cause the formation of a noxious blue smoke. The system and apparatus is caused to move a large volume of air through a furnace to provide the needed heat for drying the material to a state where it can be consumed by serving as a fuel. The air volume so moved is dust laden, and the apparatus concentrates the dust and particulate material for burning, and effectively mixes the combustible products .with cleansed air to produce a source of heat at a controlled temperature level.
sum 10F a mQv PAIENTEDNLBOW PAIENIEnJuwmsn APPARATUS AND SYSTEM FOR DISPOSING OF COMBUSTIBLE AND WASTE MATERIAL THE BACKGROUND OF THE INVENTION The invention, hereinafter set forth in more detail, is directed to apparatus for disposing of combustible and waste material, and in which the components of the apparatus are connected up in a unique system for drying the material to prepare it for use as a fuel and for also utilizing portions of the material as a fuel to produce the drying heat for other portions.
The present apparatus relates to disclosure of apparatus in my prior patent application, Ser. No. 251,182, filed May 8, 1972, and entitled Material Reducing System and Apparatus, but is now arranged to make better use of the components so that a higher percentage of materials can be used as a source of fuel to develop drying heat as well as having the good result of disposing of the material.
The invention herein has as one of its objects the arrangement of a cyclone separator, bag separator and vortex furnace in a system with a material reducing mill to reduce the size and, hence, cost of the bag separator by concentrating material fines in a conduit in by-pass of the bag separator and consuming the fines in the vortex furnace which has a banner capable of using the tines and dust from the bag separator as its fuel.
It is another object of this invention to provide a vortex furnace for burning the material fines as its source of heat, and to control the amount of air supplied to support combustion in the range of about percent excess oxygen, and to allow the bag separator to be sized for the discharge of moisture laden air or gas from the system.
A further object of this invention is to apply a vortex furnace as the heat source and to make use of the cyclonic action in the furnace for retaining oversized particles in the combustion flame until completely consumed, and to have the vortex furnace serve as a trap for unburnables which are then periodically discharged.
Still another object is to apply the apparatus in a system where after an outside source of gas or oil fuel has established a combustion flame condition in the vortex furnace, that fuel source can be cut off and the combustion cycle continued on the combustibles extracted from the material introduced to the system.
Another object of this invention is to provide the primary separator in the system with means that can control the extraction of fines in the material admitted to the cyclone, and cause the fines to pass out with the normal air flow, thereby enhancing the separation of fines from the product that is discharged at the bottom outlet from the cyclone and collected for treatment to convert it to a fuel or for other purposes.
BRIEF DESCRIPTION OF THE DRAWINGS The apparatus which is exemplary of the present invention is shown generally in schematic arrangements to illustrate the manner in which system components are caused to cooperate to achieve the objects above set forth, and wherein:
FIG. I is a schematic view of one embodiment of apparatus and system for disposing of combustible and waste material such as wood, bark, coal, and the like;
FIG. 1A is a fragmentary sectional view taken at line lA-lA of FIG. 1;
FIG. 2 is a fragmentary sectional view of a rotary valve providing means for leaking ambient air into the primary separator to increase the'amount of fines passing over with air;
FIG. 3 is a schematic view of only a portion of a complete system, as depicted in FIG. 1, for the purpose of disclosing a modified arrangement of apparatus; and
FIG. 4 is a schematic view of a system of apparatus similar to FIG. 1, but differing in the character of reducing mill for the material.
DETAILED DESCRIPTION OF THE APPARATUS Reference will now be directed to FIG. 1 of the accompanying drawing where there is schematically shown apparatus for practicing the invention heretofore briefly summarized. The primary arrangement of apparatus includes a suitable conveyor 10 for bringing the wood chips, bark, coal, and other material to be reduced to a hopper 11 which directs the material into a feed unit 12 of conventional feed screw construction having a driving motor 12A. Any feed means can be used, but it is preferred in this instance to use a screw feed mechanism and to operate the unit 12 with the hopper 11 continually filled so as to exclude as much as possible the inflow of ambient air. The screw feed unti l2 delivers the material into an upwardly directed passage 13 which opens at the upper end into an expansion chamber 14. The passage l3'includes a portion having a venturi throat 15 which is both an outlet and an inlet for a suitable mill M having a rotor 17 which is operable to run in either direction.
The expansion chamber 14 above the passage 13 opens into a conduit 18 which delivers material tangentially into a conventional cyclone separator 19 where the material flowing in the airstream is separated out through a rotary valve 20 and is collected in a suitable bin B, while the air carrying dust and fines is delivered through conduit 21 to the suction side of a blower 22. The conduit 23 from the outlet of the blower 22. The conduit 23 from the outlet of the blower 22 returns the air to the mill M at passage 13 below the venturi 15.
The apparatus of FIG. 1 is designed to reduce friable material such as wood chips and bark to a uniform product which is delivered into the bin B. The wood chips and bark, delivered to the hopper 11, are conveyed by the screw feed unit 12 into the passage 13. The blower 22 is, of course, operated to create a circulation or flow of air upward through the venturi l5 and around the circuit including the expansion chamber 14, the cyclone separator 19 and the return conduit 21 to the blower 22. A damper 24 is operably mounted in the conduit 21 near the suction inlet of the blower 22 so that the velocity of the circulating air through the venturi 15 can be regulated as desired. The material delivered to the passage 13 contains a certain percentage of dust and fines along with the larger chips, chunks and pieces. The flow through'the venturi 15 is, therefore, regulated by the damper 24 so that the fines are caused to float upwardly into the expansion chamber 14 while gravity causes the larger and heavier particles and pieces to fall through the venturi 15 where it is ground and reduced by the hammer rotor 17 and flung backwardly through the venturi 15, and exhausted by the flow being delivered through the conduit 23 below the venturi 15. The flow through the passage 13 and expansion chamber 14 will contain a fluid medium composed of dust and fines suspended in air and this medium will traverse the conduit 18 to the cyclone separator 19 where a desired separation occurs and airborne dust and fines are delivered through the top outlet conduit 21 while the material separated out is collected in the bin B.
Control over the amount of dust and fines carried out of cyclone separator 19 through the air exhaust box 25 is provided by means of a hinged skimmer vane 26 (FIG. 1A) which may be adjustably positioned more or less into the vortex flow entering the cyclone 19 from the inlet conduit 18. The vane 26 is positionable to skim out the finer or smaller portions of the material entering the cyclone 19 for flow through the exhaust box 25 and into the exit conduit 21 and delivery to the blower 22. The delivery side of blower 22 is subject to suction at the connection of conduit 27 which is connected to a bag separator 28, and the separator 28 is under suction from blower 29 through conduit 30. The portion of the material skimmed out by the vane 26 for delivery to the separator 28 and eventual delivery through a rotary valve 31 to a screw conveyor device 32 driven by motor 33 to conduit 34 is conducted to the burner 35 of a furnace 36. Thus the fines extracted by the skimming vane 26 will be consumed in the fur nace 36 to act as fuel and furnish heat for drying purposes. At the same time selective portions of the material delviere'd to the cyclone separator 19 will be collected in the closed bin B.
FIG. 1A illustrates one means for selective extraction of the dust and fines from the chamber of the cyclone separator 19. If the skimming vane 26 is not desired, the same effect can be obtained by creating the unusual leakage of ambient air into the cyclone chamber through the rotary valve 20. For this purpose, the valve (FIG. 2), driven by suitable motor means A, has its multi-bladed rotor 20A enclosed between opposed side walls 208 adjustably mounted by bolts 20C to the side plates 20D (one being seen) of the valve housing mounted at the apex of the cyclone chamber 19A. The side walls 208 can be adjusted toward or away from the path of motion of the valve blades 20A to vary the ambient air leakage into the cyclone chamber apex. The air leaking into the cyclone is greatest, and the result is that dust and fines reaching the apex zone are whisked upwardly to the outlet conduit 18 while the desired larger particles are exhausted through the rotary valve to the bin B.
Returning to FIG. 1, the apparatus is arranged with a furnace 36 which is provided with a standard wood fuel burner 35 to which an outside source of oil or gas fuel is connected at pipe 37. Combustion air is supplied into conduit 34 by conduit 38 from the blower 39. The furnace 36 has a cyclone chamber 40 lined with a suitable refractory. The cyclone chamber has an inlet at conduit 41 to deliver the hot gases through conduit 43 into conduit 23 at a junction adjacent the mill M. The furnace inlet 41 receives a supply of combustible material from conduit 44 which is connected to conduit 27 in by-pass of the bag separator 28, and a suitable valve 45 is placed in the by-pass conduit 44. A supply of combustion air for the furnace is obtained through conduit 46 controlled by valve 47. The amount of air admitted In employing the furnace 36 with a cyclone chamber 40, the non-burnables, such as sand, rock and the like, work their way along the bottom wall and can be exhausted through a dump chute 50 having a rotary valve 51. The material so dumped can be collected by a suitable belt conveyor 52 for movement to a disposal station.
The system of FIG. 1, is especially unique because it allows the use of a smaller and less expensive bag separator 28 than would otherwise be needed, and it allows the by-passing in conduit 44 of fines and the like to be used as fuel in the vortex of the cyclone chamber. Further, the system provides a way to dispose of the fines and dust extracted by the bag separator as a source of fuel for the burner 35, thereby gaining heat for drying purposes. The burner 35 does not permit the passage of large amounts of air and requires the fuel to be burned in a controlled amount of air which is normally in the range of fourteen percent excess oxygen.
The operation of the system of FIG. 1 is to produce drying heat for the incoming material, and to use portions of that material as a fuel to produce the heat for drying the product portions not used in this system as a fuel. Thus, the incoming material at passage 13 undergoes a first sorting step where the tines capable of floating in a controlled air stream are moved along to a cyclone separator 19. The larger portions of the incoming material pass by gravity to the mill M for reduction before being returned to passage 13. The second sorting step takes place in the cyclone separator 19 where the dust and fines are intentionally passed into the cyclone outlet conduit 21, thereby keeping this portion of the material out of the product portion that is discharged to the bin B. The second sorting step is accomplished either by using the adjustable skimmer vane 26 (FIG. 1A) to direct the dust and fines into conduit 21 through the exhaust box 25, or by closing the vane 26 and adjusting one or both of the rotary valve side walls 203 (FIG. 2) to allow leakage of ambient air through the product outlet to sweep the dust and fines upwardly in the cyclone 19 to the exhaust box 25. The product collected in bin 20 may be further treated to convert it to a gaseous fuel.
The flow of dust and fines in the carrier air stream in conduit 21 and blower 22 is subjected to the suction effect at the connection of conduit 27 to the outlet conduit 23 of blower 22. The dust and fines are drawn off in conduit 27 to the bag separator 28 by reason of the operation of blower 29 connected to the bag separator. The air and moisture therein is discharged to atmosphere at conduit 48, and the fines and dust are discharged by the bottom rotary valve 31 into a screw conveyor 32 which delivers the material into conduit 34. The material flow in conduit 34, along with ambient air from blower 39 is fed to the burner 35 of the furnace 36. The burner 36 is of the type that does not 7 allow the passage of a large quantity of air, so the fuel is, therefore, burned in a controlled air volume, normally in the range of about 14 percent percent excess oxygen. Because of this feature of the burner 36, and the permissible reduction in size of the bag separator 28, about percent of the air, fines, and dust is bypassed at conduit 44 directly to the furnace inlet 41. The entrance of air, fines, and dust is directed tangentially of the furnace wall, and refractory lining is used to reduce abrasion and heat effect on the furnace shell. The furance 36 acts like a cyclone and the dust and fines are concentrated toward the flame issuing from the burner where they are consumed to produce the heat that is conveyed by the air out to conduit 43. The exit heat level is maintained at about 600 F. by adjusting the air admitted at conduit 46 past valve 47.
It has been noted that the material carried into the furnace 36 contains non-combustible material. This material is moved by the cyclone action to the exhaust chute 50 where it is discharged by the rotary valve 51 onto the carry-over conveyor 52. Also, any oversize particles of material received therein remain for the time required to effect complete combustion, as such material is effectively trapped by the cyclone action and moved into the flame area under violent mixing conditions. When the burner flame has been established in the furnace 36, the outside fuel source is cut off, and the dust and fines needed to continue combustion can be supplied in sufficient amounts by adjusting the skimmer vane, or by adjusting the rotary valve side walls 20B to the desired leakage condition.
A modification of the apparatus of FIG. 1 is seen in FIG. 3 where similar parts and components are similarly enumerated so that only the additional parts and components will be described. As shown the heat outlet from the cyclone furnace 36 is conduit 43A which is connected directly to a cyclone chamber 53 where the heat level can be more closely controlled, and any particulate material carried out of the furnace 36 will have a chance to separate out and be discharged through rotary valve 54. The control of the temperature level is partly obtained by leading a portion of the exhaust flow of blower 29 through conduit 55, controlled by valve 56, to the cyclone chamber 53. The hot gas (air) issuing from the chamber 53 is led by conduit 57 into a junction (not seen but similar to FIG. 1) with conduit 23 of blower 22 adjacent the mill M.
In the operation of the system of apparatus seen in FIG. 1, the temperature of the hot gases (air) at the furnace outlet conduit 43 is desired to be of the order of 600 F. so as to be below the flash temperature of the volatiles in the wood waste. The temperature is regulated by the quantity of air brought in at conduit 46. In FIG. 2, the cyclone furnace 36 can operate at a higher temperature for better consumption of the burnable material. While the temperature of the gases issuing from furnace 36 at conduit 43A can be considerably higher than 600 R, such gases are led into the chamber 53 and mixed with clean air from conduit 55 so the final gas temperature at conduit 57 is at the desired level. Further, the cyclone action in chamber 53 throws out of the gases substantially all of the particulate material that might be carried out of the furnace.
Turning to FIG. 4, the system of apparatus is similar to that shown and described in FIG. 1, except that the hammer mill M has now been replaced with a rotary mill RM. This modified system is suitable for handling such material as coal. The difference is in the way the hot gases (air) are fed to the mill RM. A rotary or roller mill RM has the grinding rolls 58 connected to a vertical shaft 59 driven through a reduction gear train 60 and a belt drive 61 from the motor 62. The motor 62 and drive is disposed in a suitable foundation 63 which supports the scroll casing 64 surrounding the grinding chamber of the mill RM. The casing 64 has a plurality of inlets 65 opening to the grinding chamber, while the casing 64 is connected to the end of conduit 23. The hot gas supply conduit 43 is joined into conduit 23 adjacent the inlet 65. The forced flow of hot gases in the scroll casing 64 flows intothe grinding chamber and carries the material upwardly past the drive shaft 59 and into the venturi throat 15 of passage 13 in opposition to the fall of the heavy material through the venturi throat.
The mill RM is provided with a dump chute 66 opening from the bottom of the grinding chamber to the outside of the foundation 63 where the material incapable of being easily reduced is collected on a suitable conveyor 67. A valve 68 normally closes the chute outlet to avoid impairing the function of the flow of air to the venturi throat 15.
From the foregoing description it should be apparent that the apparatus, in any of its embodiments, is adapted for the efficient disposal of combustible material without generating and releasing to the atmosphere noxious fumes, or polluting the atmosphere with particulate material. In the broad view of the apparatus, it is directed to means for disposing of combustible material by processing the material in a first circulating system which includes a material reducing mill, a cyclone separator and a blower for circulating air as the carrier medium for the reduced material and for dust and fines that are inherently associated therewith. The apparatus also includes a second circulating system connected into the first system and including a separator for extracting dust and fines, a furnace in which the dust and fines are consumed by combustion, and means for returning the heat of the combustion to the first system for effectively drying the moisture that may be contained therein. The apparatus is provided in the second circulating system with means for discharging the moisture to ambient atmosphere at a temperature that is below the level that could cause noxious fumes to be released to atmosphere.
This invention is intended to cover all changes and modifications of the example of the invention herein chosen for purposes of the disclosure, which do not constitute departures from the spirit and scope of the invention.
What is claimed is:
1. In apparatus for disposing of combustible material the improvement of a mill for reducing the size of the material, conduit means to feed material into said mill, an air circulating system connected across said mill and conduit means to move reduced material and dust and fines away from said mill, separator means connected into said circulating system to remove the fines and dust from the reduced material, a drying heat producing system connected into said circulating system between said separator and mill for effecting the drying of the material in said air circulating system, said heat system including a dust and fines separator, a furnace, fuel supply means to initiate furnace operation, means connected between said dust and fines separator and said furnace to supply dust and fines into said furnace for combustion to continue furnace operation, the heat of said furnace being delivered to said mill, and means in said heat producing system to supply ambient air to regulate the temperature of the heat of said furnace.
2. The apparatus of claim 1 wherein first mentioned separator includes means for discharging reduced material from the air circulating system and for removing the tines and dust from the reduced material.
3. The apparatus of claim 2 wherein said means for removing the fines and dust is constituted by a skimming vane in said first mentioned separator.
4. The apparatus of claim 2 wherein said means for removing the fines and dust is constituted by said reduced material discharge means having a housing with a rotary valve operable in said housing, and an adjustable wall enclosing siad rotary valve with a leak passage for ambient air flow into said first mentioned separator.
5. In apparatus for disposing of combustible material and for producing a product substantially free of dust and fines, the improvement which consists of: a first circulating system having a material inlet passage connected into a material reducing mill and leading to a cyclone separator to deliver reduced material, fines and dust to said cyclone separator, a primary blower having a suction connection to said cyclone separator and a delivery connection to said miil and inlet passage, said primary blower causing the movement of reduced material, fines and dust into said cyclone separator, valve means connected to said cyclone separator to discharge the reduced material as the product, and means at said cyclone separator to remove the fines and dust from the reduced material discharged by said valve means; a second circulating system having an inlet connection adjacent said blower delivery connection and an outlet adjacent said reducing mill, said second system including a secondary blower, a bag separator connected on one side into the suction of said secondary blower and connected on the other side to said inlet connection for said second system, said bag separator having an outlet for the fines and dust, a furnace having a combustion chamber and a fuel burner connected to said chamber, means to conduct the fines and dust from said bag separator outlet into said fuel burner, means in by-pass of said bag separator to supply fines and dust into said combustion chamber for burning as a fuel, and means connecting said combustion chamber to said first circulation system adjacent said mill to supply heat for drying the combustible material introduced at said inlet passage.
6. ln apparatus for disposing of combustible material the improvement which consists in: a first circulating system having a blower to propel air as a carrier medium in said first system, a material reducing mill in said first system, means to feed material into said first system adjacent said mill for reduction in said mill and flow with the air in said first system, a cyclone separator in said first system having an outlet connected into the suction side of said blower and an inlet connected to receive reduced material from said mill along with fines and dust in said first system, and said cyclone separator having a discharge for reduced material that is substantially free of fines and dust; and a second circulating system having an inlet connection adjacent the delivery side of said blower, separator means for fines and dust connected to said second system inlet, a second blower hving a suction connection at said separator means and an outlet to atmosphere, a furnace connected into said second system beyond said separator means in the flow direction to receive the fines and dust drawn into said second system by said second blower and dispose of them by combustion, and conduit means connected to said furnace and to said first system adjacent said mill to deliver furnace heat into said first system for material drying purposes.
7. The apparatus of claim 6 wherein means is connected into said furnace to admit ambient air to regulate the temperature of the furnace delivery.
8. The apparatus of claim 6 wherein said conduit means to deliver heat into said first system includes a cyclone chamber having its inlet connected to said furnace and its outlet connected to said first system, and
a conduit connection between said second blower outlet and said cyclone chamber to supply air for regulating the temperature of the air delivery into said first system.
9. The apparatus of claim 6 wherein said cyclone separator includes valve means in said discharge to release the reduced material, and other means to effect the separation of the fines and dust from the reduced material released by said valve means.
10. The apparatus of claim 9 wherein said other means includes a casing for said valve means, and a movable component for said casing to produce a leak age passage through said valve means fro the ingress of ambient air.
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