Apparatus for comminuting solid waste

Abstract: Apparatus for crushing, grinding and shredding solid waste material in which two interacting stacks of cutting and shredding elements are positioned on two substantially parallel shafts (29,30) and mounted transversely with respect to the directions of waste material fed into the apparatus. Cutting members (26) on one stack interact with cutting members on the other stack. In each stack adjacent cutting members are spaced from each other by a spacer (28). The spacers (28) in the apparatus differ from those used in prior comminutors of this type in that they also have cutter elements (39) on their periphery and thereby serve as cutters or shredders as well as spacers. This double function of the spacers increases the efficiency of the comminuting apparatus. Most importantly there are cutting edges from the bottom to the top of each stack so that there are no intermediate elements on which strings or wires can be wrapped without encountering a cutting edge. While this is important in the shredding of relatively soft or easily shredded material, this is even more important in the comminuting of tires which have been reinforced with nylon cord or steel wire which have a tendency to wind around sections not having cutting edges. The process of effecting the difficult task of comminuting automobile and truck tires is also described.

Description: The invention relates to an apparatus for comminuting solid waste material. More specifically it relates to an apparatus according to the preamble of claim 1. An apparatus of that kind is known from DE 39 30 041. Various types of solid waste material have been the object for comminution in various types of apparatus. The comminuted material may be used for various purposes or used as land fill. Recently there has been interest in comminuting discarded tires. Huge piles of tires have accumulated in various areas which present fire hazards. Once a pile of tires catches fire, either accidentally or intentionally to dispose of the tires, the burning is difficult to extinguish and the combustion fumes or products are very damaging to the environment. To dispose of these discarded tires attempts have been to use them as land fill. One practice is to deposit garbage and solid waste to the depth of 152,4 cm (5 feet) or more and then a layer of comminuted tires is imposed. Over this layer of comminuted tires there needs to be placed a layer of dirt to a depth of 10,16 cm (4 inches) or more. In the comminution of tires the nylon cord or steel wire reinforcement used in most tires has a tendency to wrap around any rotating elements that may be in the comminuting apparatus. Therefore, apparatus of increased efficiency for cutting these cords or wires is desired. Moreover, heavy truck tires have a steel bead sometimes of 1,27 cm (0.5 in) diameter running on the inside rim of the tires which presents a drastic challenge to the comminuting capability of the apparatus. The interest in devices for comminuting waste material is evidenced by the number of patents granted for this purpose, for example, Patents Nos. 1,477,502; 3,151,645; 3,529,782; 3,664,592; 3,695,520; 3,738,582 and 4,046,324. Patent No. 4,046,324 describes two vertically arranged shafts. The cutters in each column are separated from each other by spacers which have a smaller diameter than the diameter of the cutters and which provide enough space between two adjacent cutters to allow a cutter from the other stack to enter a portion of the space between the cutters on the first stack. U.S. Pat. No. 85,067 shows apparatus for cutting straw involving a number of circular saw blades designed to cut the straw or similar fiber material. The saw blades are spaced from each other by spacers and have different diameters. A large diameter saw blade on one shaft is meshed between two blades of smaller diameter on the other shaft. Between each two large diameter saw blades there are two small diameter saw blades and each is separated from the adjacent saw blades by spacers. U.S. Pat. No. 219,170 describes circular saw blades used to disintegrate paper stock with blades of large diameter on one shaft and blades of smaller diameter on a second shaft. There is no indication of the blades meshing and the blades are separated from the adjacent blades by washers or spacers. In applicant's parent application Serial No. 07/432,198, applicant's claims were rejected on the basis of above cited U.S. Pat. No. 4,046,324 and also on 4,165,043, 4,709,197 and West German Pat. No. 2,831,953. Pat. No. 4,609,155, Japanese Pat. No. 52,269, British Pat. No. 2,026,342 and Danish Pat. No. 18,722 were also cited. The above-cited devices are shown capable of performance on easily comminuted materials, such as straw, sewage, etc. None of these have been shown capable of comminuting tires which are difficult to comminute and which have nylon or steel wire reinforcement therein and particulary huge truck tires which have a steel bead of about 12.7 mm diameter running along the inside rim of the tires. The disposal of tires has become a major problem in most areas of the United States. It is estimated that approximately 250 million tires are discarded each year. These present environmental and ecological problems. Each tire gives an average of approximately 5.7 dm 3 (l) of oil and 28.3 dm 3 (l) of combustible gas. The amount of combustible materials therein presents the danger of catching fire and difficulty in subduing the fires. In addition to the combustible nature of the materials, piles of tires are often so high and of such considerable area that it is difficult to attack the fire in such piles. Attempts have been made to use tires without comminution in land fill. When the tires are used as such with trash and garbage, the tires eventually work their way to the surface. It is found necessary therefore to comminute the tires before using in land fill. A number of states have passed legislation regulating the disposal of tires. For example, Florida, where approximately 17 million tires accumulate per year, has legislated that a disposal fee of one dollar per tire is to be paid upon the purchase of new tires. Eighty percent of the funds thus collected goes back to the respective counties for the purchase and maintenance of tire shredding equipment. These shredders, generally of the hammermill type, cost approximately US $ 175,000 or more each. This state regulates that shredded tires having no pieces of more than 5,08 cm (2 inches) in its greatest dimension may be used as land fill. In the general practice of land fill, garbage must be covered at the end of each day with a layer of at least 152,4 mm of dirt and then treated with a stabilizer or hardening material so that by the next day the dumping trucks will be supported on this surface. However, when a covering of 50 mm on comminuted rubber and 101,6 mm of dirt is used, the surface layer is sufficiently stabilized to support the trucks. This state also has anti-littering law which punishes a person found throwing away tires of 20.4 kg or more by a fine and possible confiscation of the person's vehicle. With more states growing more conscious of the necessity of regulating tires disposal, the development of more efficient equipment and processes for the comminution of tires becomes a very important factor. It is an object of this invention to nearly double the service life which is limited by the interval in which the shafts on which the cutters including the cutting means are mounted have to be dismounted for sharpening the cutting means. It is also an object of this invention to improve the efficiency of comminuting apparatus so that it may be made capable of performing more difficult tasks such as the comminuting of automobile and truck tires. It is also a special object of this invention to design equipment capable of comminuting tires having reinforcing cord or wire therein. It is also an object of this invention to design comminuting equipment capable of comminuting truck tires having steel rim beads of approximately 12.7 mm in thickness. Other objects will become obvious upon reading the detailed description of the invention as given hereinafter. In accordance with these objects the apparatus of this invention is characterized in that the driving means is capable of reversing the direction of rotation, each cutting means on the cutters and the spacer-cutters, respectively, is capable of cutting regardless of the direction of rotation of the cutters and the spacer-cutters, respectively, the apparatus being disconnectable and turnable 180° and the leads being reversible. When tires are to be comminuted by the apparatus of this invention, a feeding apparatus is used in which the tires are laid horizontally on the rollers of a conveyor system. The conveyor system initially has two sets of horizontal rolls, preferably with a downward slope to the conveyor so that by the force of gravity the tires will move downward and along the conveyor. One set of these rollers is gradually converted from its horizontal position to a vertical position so that the tires are turned from their sidewall side to their outer circular, tread side. This represents the narrowest width of the tire which is the preferred manner of feeding the tires in between the two rotating stacks of cutters. Any other manner of feeding will present problems in the comminution. This device facilitates the feeding of tires into the comminutor regardless of whether the shafts for the stacks of cutters extend vertically or horizontally. Moreover, this conveyor system keeps the operator at a greater distance from the comminutor and reduces the possibility of accidents. The dimensions of the cutters and spacer cutters may be varied somewhat in accordance with the waste material being processed. The size and shape of the teeth may also be varied somewhat in accordance with the desired results. The conditions of operation in the cutting and grinding may be varied in many ways, for example, the speed of rotation of the elements, the use of fluid for transporting material to, through and from the apparatus, periodic reversal of direction of rotation of the grinding and cutting elements, etc. The shafts on which the cutters and spacers are arranged may have cross-sections of various shapes such as hexagonal, square, rectangular, triangular, etc. The hexagonal shape is preferred. Shafts of circular cross-section may be used with one or more slots for keys to be inserted in the slots to prevent the cutters and spacers from slipping or sliding on the shafts. Circular cross-sections with one or more projections thereon could also be used. However, such circular shafts would offer more problems than the other shapes mentioned. The cutters and spacers have corresponding openings in their centers so that they can be fitted onto the shafts, preferably with the centers of the cutters and spacers coinciding with the linear or longitudinal axis of the shaft on which they are assembled. The shafts are advantageously operated at different speeds and at approriate times are counter-rotated and reversed in direction to give maximum cutting and shearing action. The apparatus of this invention can be used on various types of waste material. This may be fluid material either heavily or lightly loaded with solid material. It may also be dry solid material. A number of such cutting apparatus units may be used together either in series or parallel arangement. In most cases the apparatus is set up so that the shafts are in vertical position with the flow of waste material being effected horizontally through the cutters entering at one side of the apparatus and exiting from the opposite side. In other cases, particularly, when the waste material is dry, the shafts may be positioned horizontally and the waste material fed into the cutters by gravity flow. It is also possible to feed dry material into the cutter arrangement on vertical shafts using a chute or a conveyor belt to feed the dry material. In a preferred arrangement, a motor is positioned above the vertically arranged shafts and rotary force transmitted to one of the shafts. This is referred to as the drive shaft. Gears are positioned above the two shafts so that the two shafts are rotated at different speeds and in opposite directions, one being rotated clockwise and the other counterclockwise. Preferably the drive shaft is rotated at 60 revolutions per minute (RPM) and the driven shaft is rotated at 30 RPM. One way to effect this is with a motor giving 1750 RPM and a gear reduction of 29 to 1. The motor can be equipped so that when the cutters are jammed or over-worked by an object or piece difficult to cut, the rise on the ampere reading will effect a reversal of the motor's direction of rotation and with it the direction of rotation of the cutters. This option may be effected on a control panel (not shown). Then after a short period the motor will be turned back to its original rotation. If there is still jamming or over-working to reach the same level of ampere reading the reversal procedure will be repeated. This backward and forward procedure may be repeated a certain number of times and if the problem is not cured by a certain number of repetitions, an alarm may be sounded and/or the apparatus shut down until an attendant can clear the apparatus. If the teeth on the cutters show wear, it is possible to disconnect the apparatus, turn the apparatus 180° and reverse the leads in the motor so the cutters will rotate in the opposite directions. This makes it possible to use both sharp cutting edges on the cutting elements. It is preferred to have the teeth on the cutters aranged in vertical lines parallel with the axis of the shafts. However, where desired it is also possible to have these teeth in a spiral or helical arrangement around the shaft. This can be done by having the hexagon of the cutter turned and positioned one sixth of the hexagon from the cutter just previously positioned on that shaft. The cutting apparatus of this invention can be inserted in an arrangement with pipes through which fluid waste material is or will be flowing. In such case flanges are provided on two sides of the apparatus so that flow will be through the apparatus preferably through the lowest of the cutters and through a substantial number of cutters. The size of pipe and the size of the flanges and openings provided will vary in accordance with the type and amount of material to be processed through the apparatus. In other cases the apparatus may be set in a channel along which the waste material is flowing. In such case, flanges need not be provided but it is desirable to have the flow of fluid restricted so that it must flow through the apparatus. The description of the invention is facilitated by reference to the drawings. Fig. 1 is a side view of a preferred modification of the apparatus of this invention with a motor, jaw coupling and gear reducer mounted on top. Fig. 2 is a front view of the apparatus of Fig. 1 with the motor, jaw coupling and gear reducer removed from the top of the apparatus with a cross-section taken vertically at the middle of the apparatus going downward starting with the top housing and an open section shown in the upper part of the apparatus. Fig. 3 is an enlarged view of the seal assembly portion at the bottom of the driven shaft in Fig. 2. Fig. 4 is a cross-sectional view of the cutters and spacer-cutters portion of Fig. 2 taken at line 4-4. Fig. 5 is a similar cross-sectional view as shown in Fig. 4 in which the cutting elements of the cutters and of the spacer-cutters have a different shape form that shown in Fig. 4. Fig. 6 is a side view of a cutter with a spacer-cutter positoned thereon. Fig. 7 is a side view of a combination of a cutter and a spacer-cutter in one integral piece with a cut-away section showing the integral structure. The side view of Fig. 1 shows motor 1, jaw coupling 2 and gear reducer 3 mounted on top of the reducer adapter 5 by bolts 4 and the reducer adapter 5 is attached to housing adapter 7 by bolts 6. Housing adapter 7 is positioned above and fastened to top housing 9 with bolts 6 and top gasket 8 to effect a tight seal. Side rail 11 is fastened to the housing by bolts 10. Flanges 35 are provided so that the apparatus may be connected in a pipe line through which a fluid carrying solid waste is flowing. Coverplates 33 are fastened by bolts 34 to cover cleanout openings. Bottom cover plate 14 is bolted by bolts 15 to bottom housing 12 with bottom gasket 13 to effect a seal. In the front, partial cross-sectional view of Fig. 2, jaw coupling 16 is shown inside reducer adapter 5. The cross-sectional view is taken downward at the middle of the apparatus starting from just above the gears 18 and 18'. Gear 18 ist locked onto shaft 30 by key 36 and is driven by driving shaft 30 and gear 18 has teeth 32 wich engage gear teeth 21 to rotate driven shaft 29. With a gear ratio of 15 teeth in gear 18 and 30 teeth in gear 18' the speed of driven shaft 29 is considerably reduced from that of driving shaft 30. Various other rations may be used. In the blow-up shown in Fig. 3 the seal assembly area is identified as 24 in Fig. 2. The seal assembly is positioned below flat washer 25. This assembly comprises O-ring 24A, mating ring 24B, primary sealing ring 24C, spring 24D, and spring holder 24E. Bearing 23 is positioned below spring 24D, and above flat washer 38 which is retained in position by nut 31. In the cross-section shown in Fig. 4, cutter 26 on driving shaft 30 has teeth 27 and cutting edges 40. Above this cutter 26, spacer-cutter 28 is shown with teeth 39 and cutting edges 41. The opposite cutter 26 driven on driven shaft 29 is on approximately the same level as spacer-cutter 28 on the other shaft. The cutter on the driven shaft also has teeth 27. A spacer-cutter on this side is shown below the cutter by dotted lines. The flanges 35 provide a means for connecting the apparatus into a pipe system carrying a solid waste-bearing fluid. Fig. 5 is a similar view of apparatus in which the teeth on both the cutter and the spacer-cutter have flat side surfaces instead of the concave side surfaces shown in Fig. 4. In Fig. 5, the cutter is 26' with teeth 27' and cutting edges 41'; the shafts are 30' and 29' respectively ; the spacer-cutter is 28' and its teeth are 39' with cutting edges 40'; and the flanges are 35'. In Fig. 6 the side view of cutter 26 has three teeth 27 showing with cutting edges 40. Positioned on the cutter is spacer-cutter 28 also with three teeth 39 showing with cutting edges 41. The cutter - spacer-cutter combination may be provided in one integral unit as shown in Fig. 7 where broken section 42 shows this structure. Such units may be stacked to provide the desired arrangements of cutters and spacer-cutters. Where it is desired to have a cutter at both the top and bottom of the stack, an individual cutter disk may be added to the stack in any appropriate arrangement. Or, where it is desired to have a spacer-cutter at both the top and bottom of the stack, the unit as shown in Fig. 7 may be inverted and an individual spacer-cutter may be added in any appropriate arrangement. With the cutter - spacer-cutter arrangement of this invention there is a maximum use of cutter facitilities. There are no washers or spacers (without teeth) between teeth bearing elements. Consequently, the full length or heigth of the cutting part of this apparatus is used in the comminuting function. For most standard units the preferred dimensions for various parts of the apparatus are: cutter outside diamter (including teeth) 120.65 to 152.4 mm; cutter-spacer outside diameter (including teeth) 82.55 to 114.3 mm; inside diameter of both cutters and spacer-cutters 2" hexagon (distance from one flat side to the opposide flat side); thickness of cutter 5.588 mm to 127 mm; thickness of spacer-cutter 5.84 to 13.2 mm; thickness of teeth preferably same as cutter or spacer-cutter to which attached. Generally the teeth extend about 127 mm from the main body portion of the cutter-spacer and have a width (in the outer circumference) of about 6.35 to 127 mm. Also the clearance between a cutter on one shaft and a cutter-spacer in the other shaft is about 1.58 to 6.35mm. Larger industrial units, such as for comminuting tires, have corresponding dimensions of: cutter outside diameter 355.6 mm to 406.4 mm; cutter inside opening of 101.6 mm to 203.2 mm hexagon and cutter thickness of 44.45 mm to 76.2 mm; and spacer-cutter outside diameter of 177.8 mm to 254 mm; inside opening of 101.6 mm to 203.2 mm hexagon; and thickness of 48.26 mm to 78.74 mm; and clearance between a cutter on one shaft and opposing spacer-cutter on the other shaft of about 38.1 mm to 101.6 mm. It is desirable to have clearance between overlapping cutters of at least 0.254 mm. This is achieved by using spacer-cutters with a slightly larger thickness than that of the cutters. However, it is desirable to have a minimum of open space in the comminuting chamber that is around and between the cutter and spacer-cutter blades and between the cutting apparatus and the surrounding casing wall. The integral cutting unit as shown in Fig. 7 has a first substantially circular section and a second substantially circular section, each of the substantially circular sections having teeth extending radially from the outer periphery of the circular section, these teeth having cutting means or edges thereon, the diameter of the second circular section being substancially smaller than the diameter of the first circular section and sufficiently smaller so that the teeth extending from the outer periphery of the second circular section do not extend beyond the outer periphery of the first circular section, the integral cutting unit having an opening preferably hexagonal, at the center thereof passing through both the first and second substantially circular sections and concentric with the first and second substantially circular sections, this opening having a size and shape suitable for mounting on a shaft whereby the unit will be capable of being rotated about its center upon rotation of this shaft about its longitudinal axis. This integral cutting unit has a thickness in the second substantially circular section slightly greater than the thickness of the first substancially circular section, preferably at least 0.254 mm greater.

Claims: Apparatus for comminuting solid waste material comprising: a) a casing defining therein a comminution compartment with inlet and outlet ports (35, 35') disposed on opposite sides of said comminution compartment and adapted for the flow of solid waste therethrough; b) a first shaft (30, 30') and a second shaft (29, 29'), said first and second shafts each having an upper region and said shafts being substantially parallel to each other and positioned in said comminution compartment; c) an arrangement of cutters (26, 26') mounted on said first shaft (30, 30'), the cutters on said first shaft being adapted to be rotated upon the rotation of said first shaft upon its linear axis and said cutters on said first shaft being spaced from each adjacent cutter on the said first shaft; d) an arrangement of cutters (26, 26') mounted on said second shaft (29, 29'), the cutters on said second shaft being adapted to be rotated upon the rotation of said second shaft upon its linear axis and said cutters on said second shaft being spaced from each adjacent cutter on the said second shaft, the spacing of the cutters (26, 26') on the respective shafts (30, 30'; 29, 29') being such that the cutters on one shaft can be overlapped with the cutters on the other said shaft, with the spacing of said first shaft from said second shaft being appropriate to permit such overlapping; the said cutters (26, 26') each having cutting means (27, 27') thereon; e) a driving means (1) for providing rotational force to said first shaft (30, 30') and said second shaft (29, 29'), said second shaft being driven in a direction opposite to the rotational direction of said first shaft; f) an arrangement of spacer-cutters (28, 28') mounted between the respective cutters (26, 26') on the said two shafts (29, 29',30, 30'), one spacer-cutter being positioned between each pair of adjacent cutters on each respective shaft, each spacer-cutter comprising a spacer means to provide the appropriate space between adjacent cutters to allow the overlapping of a cutter in one said cutter arrangement with a cutter in the other said shaft arrangement; and each spacer means having cutting means (39, 39') positioned on the periphery of said spacer means characterized in that said driving means (1) is capable of reversing the direction of rotation, each cutting means (27, 27', 39, 39') on said cutters (26, 26') and said spacer-cutters (28, 28'), respectively, being capable of cutting regardless of the direction of rotation of the said cutters (26, 26') and the said spacer-cutters (28, 28'), respectively, the apparatus being disconnectable and turnable 180° and the leads being reversible. The apparatus of claim 1 in which said arrangement of cutters (26, 26') and spacer-cutters (28, 28') on said first and second shafts (30, 30', 29, 29') are arranged continuously from one linear end to the other linear end of each said arrangement whereby there are no spaces free of cutters in the length of each said arrangement on which spaces strings can be wound. The apparatus of claim 2 in which said driving means (1) applies the rotational force to said first shaft (30, 30') and said first shaft transmits rotational force to said second shaft (29, 29') through a pair of meshing gears (18, 18'). The apparatus of claim 3 in which said meshing gears (18, 18') have a different number of teeth in the respective gears whereby the said first shaft (30, 30') and said second shaft (29, 29') are rotated at different rates of speed. The apparatus of claim 3 or 4 in which said driving means (1) applies rotational force to said first shaft (30, 30'), said first shaft has affixed thereto one of said pair of meshing gears (18) and is capable of rotating said meshing gear, said second shaft (29, 29') is affixed to the other of said pair of meshing gears (18') whereby upon the meshing of said two gears the rotation of said first shaft will effect the rotation of the second shaft in the opposite rotational direction. The apparatus according to one of the preceding claims in which each of said cutters (26, 26') comprises a disc having teeth (27, 27') protruding radially from the periphery of said disc, said teeth having cutting edges (40, 40') thereon. The apparatus of claim 6 in which each of said spacer-cutters (28, 28') comprises a disc of smaller diameter than the disc of said cutter (26, 26'), said spacer-cutter discs having teeth (39, 39') protruding radially from the periphery thereof, said teeth having cutting edges (41, 41') thereon. The apparatus according to one of the preceding claims in which the cutters (26, 26') and spacer-cutters (28, 28') are arranged so that there is a minimum of space between the respective elements when in an overlapping arrangement, said first (30, 30') and second (29, 29') shafts being disposed between an upper (9) and a lower (12) housing. The apparatus according to one of the preceding claims further comprising (a) bearing means (23) for facilitating the rotation of said shafts (30, 30', 29, 29') in said housings (9, 12); and (b) fastening means for securing said housings to said casing. The apparatus of claim 1 in which said driving means (1) is an electric motor. The apparatus of claim 10 in which the said motor (1) is adapted to reverse direction of rotation when the number of amps required to drive the said motor reaches a preset limit. The apparatus of claim 11 in which the said motor (1) is automatically turned off when the present number of amps has been reached a preset number of times. The apparatus according to one of the preceding claims in which the said cutters (26, 26') mounted on said first (30, 30') and second shafts (29, 29') are individually combined with an adjacent unit of said spacer-cutters (28, 28') also mounted on said first and second shafts to form an integral unit of cutter - spacer-cutter.

Inventors: FLAMENT GREGORY J, FLAMENT, GREGORY J.
Applicants: FLAMENT GREGORY J, FLAMENT, GREGORY J.
Application year: 1991
Main classification: B02C18
IPC codes: B02C18, B29B13, B29B17