Abstract:
An apparatus, method of producing, method of operation and method of construction for producing a decoratively colored finish ground wood material includes providing a hopper adjacent a conveyor mechanism for maintaining and dispensing dry colorant onto a primary ground wood material. Further, providing and arranging a liquid dispensing mechanism adjacent an opening of a receptacle of a communition apparatus and dispensing liquid to wet the coated primary ground wood material. Lastly, grinding the wetted primary ground wood material with the comminution apparatus into a finish ground material of a lesser size than the primary ground wood material.

Description:
REFERENCE TO CO-PENDING APPLICATION  
       [0001]    This application claims the benefit of U.S. Provisional Patent Application Serial No. 60/450,730, filed on Feb. 28, 2003. 
     
    
     
       BACKGROUND OF THE INVENTION  
         [0002]    It is known in the art to prepare ground wood product chips from spent wood pallets, wood debris, or the like which have been colored by application of a liquid-borne dye for use as landscape mulch, and the like.  
           [0003]    In all known processes and equipment for coloring wood chips, the liquid dye is applied either to the finished ground wood chips as they are augered along a screw conveyor into a pile, as disclosed in U.S. Pat. No. 5,358,738, or another approach is to add both dry colorant and water combinatively into the grinding stage of a tub enclosed hammer mill or like mechanism during which the chips are colored. Finally, another known approach is to add dry colorant to a pile of ground wood chips and then to mix them together manually, such as by repeatedly scooping and dumping the material with a front end loader, a pitchfork, or the like, after which the material is introduced to a secondary grinding operation.  
           [0004]    Many of these known techniques have difficulty producing a final end product with consistent, uniform color, having no good way of metering the colorant and thus applying too much, too little or inconsistent distribution of coloring throughout a batch. Some of these processes apply dry colorant in an open air atmosphere such that the colorant is prone to being blown away by the wind. Another disadvantage is that if the dry colorant is added during or after the final grind, there may be insufficient time allotted or means for thoroughly mixing the end product material and the dry colorant for an even distribution throughout. Consequently, even if such surfaces are colored, they may be only lightly covered and may not have a uniform appearance with the rest of the product surfaces and will be prone to fading or discoloring non-uniformly with respect to the rest of the surface of the product. Likewise, applying the liquid coloring during a primary grind stage could result in subsequent uncolored or non-uniform colored surfaces of the product which are exposed in secondary grinding operations, leading to non-uniform, inconsistent product.  
           [0005]    It is an object of the present invention to overcome or greatly minimize the foregoing disadvantages of the known prior art.  
         SUMMARY OF THE INVENTION  
         [0006]    This invention is directed to methods of constructing a system used for producing colored wood chip material and to methods for coloring ground wood chip material. One method of constructing a comminution and coloring system having a dry colorant application system and being capable of grinding or chipping wood material to produce a decoratively colored finish ground material provides a container for maintaining dry colorant particles, with an opening in the container for dispensing the dry colorant particles onto a primary ground wood material of an initial size as the chips exit a grinder or chipper. The method includes maintaining the container adjacent an outlet conveyor mechanism of the communition apparatus to provide for disbursement of dry colorant particles from the container onto the primary ground wood material transferring along the outlet conveyor mechanism. Further, the method includes providing a liquid dispenser or a spigot adjacent a receptacle of communition apparatus functioning as a secondary grinder and dispensing water through the spigot into the receptacle at a controlled rate to wet the primary ground wood material that has been uniformly coated with dry colorant particulate. The wetted primary ground wood material is then further ground into a finish ground chip material of a lesser size than the primary ground wood material during which steps the dry colorant particulate is impregnated within the finish ground wood chip material, thereby altering the visual appearance of the primary ground wood material to take on the desired decorative color.  
           [0007]    Another aspect of the invention includes providing a method for producing a decoratively colored finish ground wood material utilizing a comminution apparatus. The method includes providing a primary ground wood chip material of an initial size and conveying the primary ground wood chip material along a path. Further, the method comprises dispensing dry colorant particulate substantially uniformly onto the primary ground wood chip material as it is being conveyed. Next, it involves transferring the primary ground wood chip material with dry colorant particulate disbursed thereon into the receptacle of a comminution apparatus. Next, water is sprayed onto the primary ground wood chip material with dry colorant particulate dispersed thereon. Finally, the wetted primary ground wood chip material with colorant particulate thereon is further size reduced to impregnate the dry colorant uniformly within the ground wood chip material to produce the decoratively colored finish ground wood chip material of lesser size desired.  
           [0008]    One advantage of the invention is that it provides a method and apparatus for producing a uniformly colored finish ground wood chip material.  
           [0009]    Another advantage of the invention is that the method and apparatus produce a colored ground chip material that resists fading.  
           [0010]    Another advantage of the invention is that the method and apparatus minimize dry colorant particulate waste during the manufacture of the colored ground wood chip material.  
           [0011]    Another advantage of the invention provides a method and apparatus for producing a uniformly colored ground wood chip material at a variable production rate.  
           [0012]    Another advantage of the invention provides a system allowing an operator to control and meter the dry colorant particle disbursement rate and the water disbursement rate to produce a uniformly colored ground wood chip material.  
           [0013]    Another advantage of the invention provides a dry colorant system that is adaptable to a variety of standard comminution machines.  
           [0014]    Another advantage of the invention provides a comminution apparatus that can be operated with or without operation of a dry colorant system.  
           [0015]    Another advantage of the invention provides a method and apparatus permitting utilization of a single comminution apparatus to produce a colored ground wood chip material.  
           [0016]    Another advantage of the invention provides a relatively simple and economical method and apparatus for producing colored ground wood chip material.  
           [0017]    It should be recognized that one ordinarily skilled in the art will recognize other advantages of this invention by viewing the complete disclosure herein, and that the above represents only a partial listing of advantages provided by this invention. 
       
    
    
     THE DRAWINGS  
       [0018]    The presently preferred embodiment is disclosed in the following description and in the accompanying drawings, wherein:  
         [0019]    [0019]FIG. 1 is a partial perspective view of a comminution apparatus having a colorant system constructed according to one presently preferred embodiment of the invention;  
         [0020]    [0020]FIG. 2 is a partially broken away side elevation view of the comminution apparatus of FIG. 1;  
         [0021]    [0021]FIG. 3 is a partial plan view looking in the direction of arrow  3  of FIG. 2;  
         [0022]    [0022]FIG. 4 is an exploded perspective view showing a dry colorant hopper of the apparatus of FIG. 1;  
         [0023]    [0023]FIG. 5 is an assembled perspective view of the dry colorant hopper with a cover in an open position;  
         [0024]    [0024]FIG. 6 is an enlarged fragmentary perspective view showing a portion of a control mechanism of the colorant system;  
         [0025]    [0025]FIG. 7 is a fragmentary perspective view of a conveying system of the colorant system;  
         [0026]    [0026]FIG. 8 is a fragmentary perspective bottom view of a portion of the colorant system;  
         [0027]    [0027]FIG. 9 is a schematic diagram illustrating another embodiment of the presently preferred method for producing a colored ground wood chip material; and  
         [0028]    [0028]FIG. 10 is a flow chart illustrating a control system for producing the colored ground wood material. 
     
    
     DETAILED DESCRIPTION  
       [0029]    [0029]FIGS. 1 and 2 illustrate a comminution apparatus, for example, and without limitation, a tub grinder  10  incorporating a dry colorant system  12  for applying a dry colorant particulate, referred to as dry colorant  11  hereafter, to a primary ground wood material  13  (FIG. 9), which may be wood chips ground from spent wood pallets, wood chip products or debris, or the like. The ultimate object is to produce a uniformly colored wood chip material  15  (FIG. 9) using either a secondary reducing grinder, represented here as a tub grinder  10 ′ or returning the primary ground wood chip material  13  to the tub grinder  10  for a secondary grind to produce the finish ground wood chip material  15  which is lesser in size than the primary ground wood chip material  13 . It should be understood that the invention contemplates the use of a variety of types of wood grinders, other than tub grinders, such as but not limited to horizontal feed wood grinders, gravity feed wood grinders, and the like, incorporated herein by reference.  
         [0030]    The tub grinder  10  which may be of the construction shown in Morbark&#39;s U.S. Pat. No. 5,419,502 issued May 30, 1995 which is incorporated herein by reference, has a tub or chamber  14  in which an operator places wood material, such as scrap wood pallets, wood debris or the like, for grinding the material into the primary ground wood material  13 . The chamber  14  has an outer cylindrical wall  16  arranged for rotation relative to a base  18  (FIG. 3). Still referring to FIG. 3, the rotating wall  16  may be suitably driven by a rotary hydraulic motor  20  which may be driven by a pump driven by a diesel engine, or could be mechanically coupled to the diesel engine (not shown). An output shaft  22  of the motor  20  mounts a sprocket  24  which, via a chain  26  revolves a pair of idler sprockets  28  on idler shafts  29 . As the motor  20  operates to rotate the sprocket  24 , the chain  26  engages a series of arcuate racks  30  fixed around the circumference of the wall  16 . Accordingly, the wall  16  is caused to rotate relative to the generally fixed base  18  about a central axis  32  of the wall  16 .  
         [0031]    Still referring to FIG. 3, the base  18  of the tub  10  has an opening  34  wherein a hammer mill  36  is supported by an elongate shaft  35  within a housing (not shown) for rotation with the shaft  35 . As the hammer mill  36  rotates, a plurality of hammers  37  attached to the hammer mill  36  forcefully engage the wood material rotating about the axis  32  in the chamber  14  to cut or grind the material against an anvil  38  typically supported by the base  18  adjacent at least one side of the opening  34 . As shown in FIGS. 1, 2,  7  and  9 , upon the material being chipped or ground, the material is discharged from the tub  10  into a bottom feed auger-type screw conveyor  40 , represented here as a pair of rotating augers  42 ,  43  driven preferably hydraulically in opposite directions in a material channel or trough  44 .  
         [0032]    As shown in FIG. 9, upon initially grinding the raw wood material into the primary ground wood material  13 , typically the wood chip material  13  is between three inches by five inches (3″×5″) to four inches by six inches (4″×6″) in size. The primary ground wood material  13  is transferred by the augers  42 ,  43  along the trough  44  from beneath the opening  34  toward an outlet or discharge end  46  (FIG. 1) where the primary ground wood material  13  is discharged onto a belt conveyor  48 . The belt conveyor  48  carries the primary ground wood material  13  upwardly and then discharges the material from the conveyor  48  into a storage pile  50 , as desired.  
         [0033]    The apparatus  10  described may be of the type manufactured by the assignee of the present invention, such as the Morbark 1300 Tub Grinder available from Morbark, Inc. of Winn, Mich. Other primary grinders that may be used includes the Morbark 4600 Wood Hog, and Morbark 1300 HMV also available from Morbark, Inc. It should be understood that the above grinders may also be used for a secondary grind operation with a screen change to provide a mesh with smaller openings to produce the final ground wood chip material  15 , as discussed in more detail hereafter. It should also be recognized that the screw-type augers  42 ,  43  are presently preferred, but other conveying mechanisms may be used to convey and mix the primary ground wood material  13  and the dry colorant  11 , such as belt conveyers for example, and the like.  
         [0034]    As shown in FIG. 1, it should be understood that the apparatus  10  may incorporate an operator&#39;s cab  52 , wherein an operator may remotely control the function of the individual mechanisms operably attached to the apparatus  10 . Preferably, the cab  52  has a plurality of actuatable switches or levers, wherein at least one lever  54  operably communicates with the chamber  14  to control the rate or angular velocity at which the chamber  14  rotates relative to the base  18 . When the tub grinder  10  is to function also as the secondary grinder, another lever  55  is preferably incorporated and operably communicates with a primary vessel  58  to control the flow rate at which water is discharged from the vessel  58  (discussed il more detail hereafter). Yet another lever  56  is preferably incorporated to operably communicate with dry colorant containing container or hopper  60  to control the discharge rate of the dry colorant  11  from the hopper  60  (discussed in more detail hereafter). It should be understood that the levers  54 ,  55 ,  56  may be used to manually control their respective functions independently of one another, or their respective functions may be communicated through a central processing unit (CPU)  63  so that the functions are automatically adjusted relative to one another (FIG. 10), generally dependant upon the rate at which the chamber  14  rotates. It should also be understood that the levers  54 ,  55 ,  56  communicate with the chamber  14 , the primary vessel  58  and the hopper  60 , respectively, through any suitable control mechanism, such as for example, hydraulic controls, pneumatic controls, radio frequency controls, electromechanical controls, and the like.  
         [0035]    Upon the raw wood material being ground into the primary ground wood material  13 , the primary ground wood material  13  falls through the opening  34  of the chamber  14 , through a set of grates having openings of a desired size (not shown) and onto the augers  42 ,  43 . The primary ground wood material  13  travels along the trough  44  and generally beneath the hopper  60  where the dry colorant  11  is discharged at a controlled rate onto the primary ground wood material  13  by the dry colorant system  12 .  
         [0036]    The dry colorant system  12  communicating with the apparatus  10  is operative to apply the dry colorant  11 , for example and without limitation, red, black or green in color, to the primary ground wood material  13  before any secondary grinding operations are performed on the primary ground wood material  13 . The system  12  preferably has the hopper  60  mounted on a support frame  62  (FIG. 7) in a position generally over the conveyor  40  or augers  42 ,  43 . As best shown in FIGS. 4 and 5, the hopper  60  preferably has a hinged lid  64  which, when opened, allows the dry colorant  11  to be charged into the hopper  60 . The hopper  60  preferably has a tilted or slanted floor  66  which gravitationally directs the colorant  11  toward an opening  68  in a bottom surface  69  of the hopper  60 .  
         [0037]    As best shown in FIGS. 4, 6 and  8 , to control the discharge rate of the dry colorant from the hopper  60  onto the primary ground wood material  13 , the hopper  60  is generally equipped with a metering system  70 . As best shown in FIG. 6, preferably the metering system  70  is driven by a hydraulic motor  72  that is coupled by hoses  74  to a hydraulic control system  76 .  
         [0038]    As best shown in FIGS. 4, 5 and  8 , the metering system  70  communicates with an auger  78  operably connected to the hydraulic motor  72 . The auger  78  is rotatably received along the length of the opening  68  in the hopper  60 . The auger  78  may be constructed in any suitable manner, and is shown here having a bead  80  of material bonded to a generally cylindrical length of rod material  82 , wherein the bead  80  is in a generally helical configuration. In addition, at least one,. and shown here as a pair of compliant seals  83 , preferably constructed from a rubber or plastic material, are attached adjacent the opening  68  of the hopper  60  and generally engage the auger  78  to facilitate regulating the discharge rate of the dry colorant  11  from the hopper  60 . The metering system  70  controls the rate of feed of dry colorant  11  in accordance with the speed of augers  42 ,  43  and the quantity of primary ground wood material  13  traveling along the conveyor  40  in order to produce an optimal coverage of dry colorant  11  on the primary ground wood material  13  and to reduce waste of the dry colorant  11 . Preferably, as shown schematically in FIG. 10, the discharge rate of dry colorant  11  from the hopper  60  is automatically adjusted by the CPU  63  or may be manually set by the operator via lever  56 . Desirably, the CPU  63  adjusts the discharge rate of dry colorant  11  to coincide with the rate of rotation of the chamber  14  and speed of rotation of augers  42  and  43 . Additionally, upon the level of dry colorant  11  within the hopper  60  reaching a low level condition, preferably, a sensor  65  operates to send a signal to the operator in the cab  52 . Desirably, the sensor  65  illuminates a light, or rings an alarm (not shown) within the cab  52 . It should be recognized that other mechanisms may be used to indicate to the operator that a low dry colorant level condition exists within the hopper  60 , such as, for example and without limitation, a window  67  (FIGS. 4 and 5). The window  67  allows the operator to view inside the hopper  60  to readily see the dry colorant  11  in the hopper. As such, when the level of dry colorant  11  within the hopper reaches a low level condition, the operator may visually see the low level condition.  
         [0039]    Upon having dry colorant  11  discharged onto the primary ground wood material  13 , the material  13  travels along the trough  44  where the augers  42 ,  43  operate not only to distribute the dry colorant  11  uniformly over the outer surfaces of the primary ground wood material  13 , but also to impregnate the dry colorant  11  into the primary ground wood material  13 , thereby reducing the possibility of the dry colorant  11  not adhering to the primary ground wood material  13 .  
         [0040]    Upon churning and blending the dry colorant  11  with the primary ground wood material  13  via the augers  42 ,  43 , the material  13  is preferably discharged onto the belt conveyor  48 , where the material  13  is preferably conveyed to a storage pile  50 . Once the primary ground wood material  13  having dry colorant  11  uniformly distributed thereon is in the storage pile  50 , the material  13  may be stored for several hours or days before further processing, or it may be immediately fed directly in line to a secondary grind process, discussed in more detail hereafter. It should be recognized that the primary ground wood material  13  with dry colorant  11  uniformly distributed thereon may be routed back into the chamber  14  of the same comminution apparatus  10  that produced the primary ground wood material  13 . In this case, only one apparatus  10  is required to produce the finished and colored ground wood material  15 . The supply of dry colorant  11  is first deactivated and the water supply to the tub  14  is activated to spray a predetermined volume of water upon the revolving mass of first stage chips returned to the same tub grinder  10 . The tub grinder  10  may be operated at an increased speed and may have replaced screens with a reduced mesh size (not shown) beneath the hammer mill  36 . New surfaces will be cut in this reducing action which have not been coated with dry colorant.  
         [0041]    The water is maintained in the vessel  58  and communicated to the primary ground wood material  13  in the chamber  14  via a hose or conduit  86 . Desirably, the conduit  86  is coupled to an outlet or spigot  84  to facilitate dispensing the water uniformly on the primary ground wood material  13 . As shown in FIGS. I and  2 , the vessel  58  can be attached to the frame of the comminution apparatus  10  so that water supply can be transported along with the comminution apparatus  10 . Otherwise, it should be recognized that a secondary vessel  90 , or other source of water supply, such as, for example and without limitation, a well, containing water may be operably connected to the apparatus  10  via a secondary conduit  92  either connected to the vessel  58 , as shown, or directly to the spigot  84 , not shown.  
         [0042]    As shown in FIGS. 1 and 2 wherein the coarse grinder or tub grinder  10  is also used as the reducing grinder or secondary grinder and like numerals are used to designate the water supplying elements, the water flow rate from the spigot  84  is desirably regulated by a water metering device  88  operably communicating with the chamber  14 . The water metering device  88  may be in communication with the CPU  63  so that the CPU  63  can regulate the discharge rate of water from the spigot  84  in proportion to the rate at which the chamber  14  rotates or may be manually controlled by the operator directly or remotely so that lever  55  will control the flow rate according to the speed of the chipper. As such, an optimal amount of water can be dispensed onto the material  13  to obtain an optimal mix of water and colorant bearing primary ground wood material  13 .  
         [0043]    Desirably, the water metering device  88  is also able to detect the water level within the vessel  58 . As such, when the water level in the vessel  58  reaches a low level condition, a signal can be sent to the operator in the cab  52 . Desirably, the signal illuminates a light or rings an alarm (not shown) in the cab  52 . As best illustrated in FIG. 10, it should be understood that the operator within the operator&#39;s cab  52  can either control the rate at which the chamber  14  rotates, thereby automatically controlling the rate at which water discharges from the valved spigot  84  via the CPU  63  controlling the positions of the spigot valve, or the operator may manually override the water metering device  88  and the CPU  63  to have the water discharge from the spigot  84  at some other desired rate or closed off.  
         [0044]    Once the supply of primary ground wood material  13  having dry colorant  11  uniformly distributed thereon is combined with the water in the chamber  14 , and upon being reduced to the final ground wood material  15 , the final ground wood material  15  is further churned by the augers  42 ,  43 . As such, the dry colorant  11  is further impregnated within the final ground wood material  15 , thereby further improving and enhancing the useful life of the final product  15 . The finished ground wood material  15  is carried to a secondary belt conveyor  48 ′ where the final ground wood material  15  may be discharged to a final storage pile.  
         [0045]    Referring now to FIG. 9 wherein an alternative reducing grinder or secondary grinder is used, the primary ground wood material  13  having been uniformly coated with dry colorant  11  may be charged to a secondary comminuting apparatus, which as mentioned, may be another tub grinder  10 ′ (FIG. 9) of the same construction as in the primary grind process described. Upon charging a chamber  14 ′ with the primary ground wood material  13  having the dry colorant  11  uniformly covering and impregnating its exposed surfaces, the material  13  is reground in a secondary hammer mill  36 ′ with an adjacent finer mesh screen than in tub grinder  10 . Prior to regrinding the primary ground wood material  13  into the finish ground chip material  15 , typically having a reduced chip size approximately three inches by five inches (3″×5″), and more typically on the order of about two inches by three inches (2″×3″), water is introduced into the chamber  14 ′ to at least partially wet the primary ground wood material  13 .  
         [0046]    The final ground wood material  15  having colorant  11  uniformly impregnated in all its surfaces may either be packaged immediately, or remain in the final storage pile  94  indefinitely. Further, it should be recognized that the final ground wood chip material  15  may be transported along the belt conveyor  48 ′ for immediate packaging, and thus not be transported to the final storage pile  94 .  
         [0047]    As mentioned above, it should be understood that the comminution apparatus  10  described above in connection with the primary grind operation may be used for the secondary grind, but with operation of the dry colorant system  12  closed down.  
         [0048]    The above represents presently preferred embodiments of the invention, and those skilled in the art will appreciate that the same or equivalent constructions and processes can be adapted to any of a number of grinding systems presently known or yet developed and the invention is not to be limited by the particular embodiments described above. For example, while a dual auger screw  42 ,  43  conveyor has been described in connection with the primary grinder and is preferred, a single auger screw or other types of conveyors which would act to blend the dry colorant  11  with the primary ground wood material  13  prior to introduction to the secondary grind operation could be employed and are contemplated by the present invention. Also, any of a number of different known or yet to be developed metering systems which could effectively supply the dry colorant  11  to the primary ground wood material  13  during its conveyance for uniform blending are contemplated and incorporated herein by reference. Also, while hydraulics have been described as the means of driving the augers  42 ,  43  of the primary grinder  10  and dry colorant metering system  70  coupled by a suitable hydraulic control system, other types of drives such as chain or belt drives, electric motors, pneumatic drives and the like now in existence or yet to be developed could be employed and are incorporated herein by reference, provided they achieve substantially the same result of controlling the relative application of the colorant  11  in relation to the feed of the primary ground wood material  13  for metered application and blending of the dry colorant  11  with the primary ground wood material  13 .  
         [0049]    It is to be further understood that the term “dry colorant” means a concentrate of the coloring material prior to adding the water or other liquid carrier solution (i.e., non-water solvents, such as alcohol or the like) used in the secondary grind stage to ultimately “color” the finished ground wood material  15 . The dry colorant  11  can be in any particulate form in which it will adhere to the wood chips.  
         [0050]    It is understood that the disclosed embodiment is representative of a presently preferred form of the invention and that others that accomplish the same function are incorporated herein within the scope of the claims that follow. The term grinder system as used in the claims refers to either grinder  10  as shown in FIG. 1 when the coated primary chips are returned to housing elements  36  or to a combination of grinders  10  and  10 ′ in the FIG. 9 embodiment when the primary grind is passed on to grinder housing elements  36 ′ and the water is introduced to tub  36 ′.