Apparatus and method for treating mulch

Abstract

An apparatus and method for treating mulch include a mobile facility that applies a treatment to wood fibers at an increased efficiency than conventional coloring or coating methods. The method includes the steps of introducing the wood fibers into a revolving tub, and transporting the wood fibers to a first treatment manifold. The first treatment manifold includes at least one inlet port to receive a first treatment and at least one discharge port to apply the first treatment to the wood fibers. The wood fibers are treated with the first treatment using the first treatment manifold. The apparatus includes a revolving tub and a first treatment manifold, which is preferably installed in the revolving tub in a first treatment area.

Description

BACKGROUND OF THE INVENTION

1. Field of the Invention

The invention generally relates to apparatus and method for coating treatment of wood fiber such as mulch or wood chips.

2. Description of Related Art

Landscaping materials, such as wood chips and wood mulch are currently available in their normal natural colors, and in some cases, are available colored in various colors, for example, in black, brown and red. The conversion of natural wood or other plant fiber-based substrates to colored substrates is currently a rather sloppy, inefficient, expensive, and, in some cases, environmentally unfriendly process. In the case of converting natural mulch to colored mulch, or natural chips to colored chips, the process is highly inefficient. In order to color mulch or chips, a producer of such colored product typically purchases a pigment suspension of an appropriate color. For example, if the suspension is carbon to produce a black product, it typically ranges from about ten pounds per gallon to about eleven pounds per gallon, and about twenty-five to fifty weight % carbon pigment. Typically, the carbon suspension is distributed in 55-gallon drums weighing approximately 500 net pounds and containing about 150 to 250 pounds of carbon. Currently, in order to apply this concentrated pigment dispersion to the substrate to be colored, the producer dilutes it with a substantial volume of water, up to a 60:1 dilution in some cases, bringing the final volume from 55 gallons to as much as 3300 gallons or more. The mulch is essentially then slurried in this highly diluted pigment dispersion. This results in a water saturated product which must be allowed to dry for extended periods of time before it can be used, and still may contain excessive water, adding significantly to the shipping weight and thus the shipping costs.

Some currently available mulch colorant devices can process mulch at the rate of 80-200 cubic yards per hour, consuming about 25-70 gallons of water per minute, or about 1,500-4,200 gallons of water per hour. This volumetric flow rate converts to about 15 to 20 gallons of water per cubic yard of mulch treated. At a mid-range black color level using a carbon black pigment dispersion, and 200 cubic yards per hour, 3.33 cubic yards per minute, the carbon dispersion feed rate is about 0.5 to 1.5 gpm, corresponding to about 5 to 15 pounds per minute of carbon dispersion or about 1.3 to 5.3 pounds of carbon pigment per minute, where the dispersion is approximately 25 to 35% carbon by weight. This corresponds to about 0.4 to 1.6 pounds of carbon pigment per cubic yard of mulch.

Assuming a pigment dispersion having 30 weight percent carbon pigment, in one hour, 200 cubic yards of mulch will be colored, using 3,600 gallons of water and 666 pounds of carbon dispersion (or 200 pounds of carbon pigment). Since the wet colored mulch weighs about 700 pounds per cubic yard, the total mass of mulch, wet, is approximately 140,000 pounds, including the added total weight of water of about 30,000 pounds, along with 666 pounds of carbon dispersion, or approximately 30,700 pounds total, added weight.

Depending on the substance or substances from which the mulch is made, the untreated mulch may contain anywhere from 10 weight percent to 75 weight percent moisture, from very dry pallet wood to mulch exposed to excessive rainfall. Where the moisture content of the mulch material is essentially about 60+ weight percent moisture, there is little capacity to absorb significant additional water, meaning that the colored water solution is mostly wasted.

If the mulch is able to absorb 10 percent moisture weight from the colored water solution, as an example, approximately 13,000 pounds of water would be absorbed and 19,000 pounds, 2278 gallons (60 percent), would be lost as overflow, runoff, or post-treatment bleeding. This is not only an inefficient use of materials, but, depending on the colorant being employed, may also be an environmental hazard.

Moreover the conventional methods of dying the mulch, woodchips etc., require substantial processing equipment. This typically necessitates a processing plant with specifically designed equipment for coloring mulch. Such plants are inefficient and expensive, adding to the cost of the final product.

SUMMARY OF THE INVENTION

An apparatus and method are described for treating mulch, where a mobile facility can apply a coating to wood fiber at an increased efficiency than conventional coloring or coating methods.

In one embodiment, the method of treating a plurality of wood fibers includes the steps of introducing the wood fibers into a revolving tub, transporting the wood fibers to a first treatment manifold, and treating the wood fibers with the first treatment using the first treatment manifold. The first treatment manifold is located within the revolving tub and includes at least one inlet port to receive a first treatment and at least one discharge port to apply the first treatment to the wood fibers. The first treatment manifold is preferably mounted to a floor of the revolving tub.

In another embodiment, the method further includes the steps of transporting the wood fibers to a second treatment manifold and treating the wood fibers with a second treatment using the second treatment manifold.

In yet another embodiment, the method further includes the step of grinding the wood fibers to a smaller nominal size.

In another embodiment, the method further includes the step of delivering a material to be used to treat the wood fibers to the first treatment manifold.

The treatment preferably includes a colorant, and the treatment is preferably provided as a foam.

In yet another embodiment, the method further includes, prior to treating the wood fibers with the first treatment, the steps of combining the first treatment, a foaming agent, and a solvent to form a landscaping composition and foaming the landscaping composition to form a delivery medium for delivering the first treatment to the wood fibers.

In another embodiment of the present invention, the apparatus for treating a plurality of wood fibers, includes a revolving tub and a first treatment manifold mounted to the revolving tub. The first treatment manifold includes at least one inlet port to receive a first treatment and at least one discharge port to apply the first treatment to the wood fibers.

The first treatment manifold is preferably mounted to a floor of the revolving tub. The first treatment manifold preferably has sloped sides for allowing the wood fibers to roll over the first treatment manifold.

The apparatus preferably includes a grinding machine having at least one tooth to grind the wood fibers into a plurality of smaller pieces. The grinding machine is preferably a grinding mill mounted to a floor of the revolving tub. The discharge port is preferably aimed toward the grinding mill. The grinding machine preferably also includes a cutting screen, with openings sized to match a desired particulate size for wood fibers particles.

In yet another embodiment, the apparatus preferably also includes a second treatment manifold in a second treatment area for treating the wood fibers with a second treatment. The second treatment manifold includes at least one inlet port to receive the second treatment and at least one discharge port to apply the second treatment to the wood fibers. The second treatment manifold treats the wood fibers after the wood fibers have been ground in the grinding machine.

The apparatus preferably also includes an engine coupled to the grinding mill and a hydraulic motor coupled to the revolving tub. The apparatus preferably also includes a transportable carrier, wherein the revolving tub is mounted on the transportable carrier.

The treatment is preferably provided as a foam, as a mist, or in water. The treatment is preferably at least one dye, at least one pigment, at least one oil, at least one fragrance, at least one insect repellent, at least one insecticide, at least one fungicide, at least one wood preservative, or any combination of these.

In another embodiment of the present invention, the method of treating a plurality of wood fibers includes the steps of introducing the wood fibers onto a feed table, conveying the wood fibers along the feed table to a first treatment manifold, treating the wood fibers with the first treatment using the first treatment manifold, and grinding the wood fibers in a grinding mill. The first treatment manifold includes at least one inlet port to receive a first treatment and at least one discharge port to apply the first treatment to the wood fibers. The wood fibers travel from the feed table over the manifold and into the grinding mill.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic illustration of a method and apparatus for coating and grinding wood fibers according to an embodiment of the invention.

FIG. 2 is a schematic illustration of an apparatus for coating and grinding wood fibers according to another embodiment of the invention.

FIG. 3A schematically illustrates the coating process according to an embodiment of the invention.

FIG. 3B schematically illustrates the coating process according to another embodiment of the invention.

FIG. 4A-1 is a schematic representation of a manifold in an embodiment of the present invention shown in planar (isolation) view.

FIG. 4A-2 is a schematic representation of the manifold of FIG. 4A-1 shown in side (elevation) view.

FIG. 4B shows a manifold installed on the floor of the revolving tub or tub grinder in an embodiment of the present invention.

FIG. 4C shows the injection ports to a manifold as viewed from the underside of the floor of the tub grinder.

DETAILED DESCRIPTION OF THE INVENTION

PCT application Publications WO/03103844A2, WO/03103840A1, WO/03084743A1, WO/03084670A1 as well as U.S. Published application No. US20030213168A1, filed by Applicant(s) are incorporated herein in their entireties as a part of the disclosure of the present invention.

An apparatus and method are described for treating mulch, where a mobile facility can apply a coating to wood fiber at reduced cost and increased efficiency than conventional coloring or coating methods. Preferred embodiments of the apparatus are capable of being operated with efficient water and pigment consumption, reduction of the moisture content of the coated product and environmental efficiency. Although several examples below describe apparatuses in which the treatment is a colorant, other treatments may be applied, as described further below.

In accordance with one embodiment of the invention, an apparatus for coating mulch includes a receiving tub or a “tub grinder” with a manifold and a grinding mill. The manifold is preferably armor-coated or armor-plated and made of heavy-duty hardened steel to withstand the force of the materials being dumped onto the top of the manifold. The manifold preferably has a sloped design to allow material to roll over the top of it. A sloped design also allows the materials to glide over it and into the mill without being or creating an obstruction. The manifold is preferably fabricated to extra heavy duty standards to withstand extreme impact, wear and abrasion as normally encountered on the floor of the tub grinder, where large tree stumps and other debris are routinely placed into the tub grinder. The fresh fiber includes, but is not limited to, the form of tree parts, stumps, pallets, post manufacturing wood waste, mulch or chip wood (collectively termed herein “wood fiber” and also known as landscaping material).

In a preferred embodiment, the wood fiber is deposited into the tub grinder, and the rotating tub directs the wood fiber particles to the grinding mill, which is located near an edge of the tub grinder floor. The manifold is preferably located near the feed opening of the grinding mill but toward the center of the tub floor. The manifold preferably includes multiple coating inlet ports and discharge ports. The nozzles of the discharge ports are preferably aimed in the direction of the grinding mill. The nozzles are preferably aimed at the fiber particles as they are pulled into the mill. In alternative embodiments, there may be only a single inlet port. The coating inlet ports are coupled to a colorant source by flexible hoses because the entire tub (floor and revolving outer wall) is hinged on one side of the trailer frame and hydraulic cylinders pivot the tub to a position more than 90 degrees (from horizontal to vertical position) to the side of the trailer frame, providing access to the grinding mill and to remove undesirable materials from within the tub. During the grinding process, the tub floor (horizontally positioned to the trailer frame) remains stationary as the outer drum or vertical wall of the tub revolves thereby directing the material within the tub to fall into the opening in the floor that is positioned above the grinding chamber inlet. The flexible hoses allow the tub to hydraulically pivot and the connection of the colorant source and the manifold inlet ports remain intact.

The wood fiber is brought into contact with, or in close proximity to, the discharge ports where they are substantially coated with the colorant. The distance between the wood fiber and the discharge port can vary, as long as the wood fiber is in close enough proximity to the discharge ports to receive a coating of colorant.

In preferred embodiments, the colorant is supplied in the form of foam. If the colorant is supplied as a foam, the amount of liquid absorbed by the wood fiber is substantially reduced, and the fiber essentially only receives a surface coating. This reduces cost, weight and subsequent drying time. In alternate embodiments, the colorant is supplied as a mist or as a dispersion in water.

Once coated, the wood fiber is transported from the coating area to the inlet of a grinding mill through the grinding chamber and onto a conveyor device. The conveyor device is preferably a collection auger or conveyor belt. The conveyor device transports the wood fiber to another location of the grinder where additional coating is preferably applied by a post-treatment manifold.

FIG. 1 is a schematic illustration of a method and an apparatus for coating and grinding wood fibers according to one embodiment of the invention. Referring to FIG. 1, the machine loading device 120 is shown loading the wood fiber 110 into the revolving tub 100. As discussed herein the term wood fiber is used to inclusively refer to mulch, wood chip, and any other fibrous or non-fibrous particles. As can be seen from the embodiment of FIG. 1, the revolving tub 100 is coupled to an engine 105 and mounted on an over the road transportable carrier 107. Portability is particularly advantageous because it enables size reduction and coating of the wood fibers at the construction site instead of transporting the untreated material to a designated plant or remote location for further treatment or coating. A manifold 135 is installed onto the floor 111 of the revolving tub 100. The nozzles of the outlet ports 137 are aimed at the grinding mill 150. Once the wood fibers 110 enter the revolving tub 100 (also known herein as the tub grinder, and the terms are used interchangeably herein), the wood fibers are directed (see direction 130) over the manifold 135 to the coating area 140. The coating area 140 is preferably located in the proximity of the manifold 135 and prior to the inlet of the grinding mill 150.

The grinding mill 150 preferably serves multiple purposes. It acts as a conveyor device for transferring wood fiber particles to the conveyor auger 155. In addition, it reduces the size of the larger wood fiber particles into smaller particles for a desired application. During the size reduction process, new facets are uncoated and revealed in the wood fiber particles 310 and an additional coating procedure or post treatment processing is preferably used to complete the uniform coating. Suitable sized wood particles exit the cutting screen 230 and the auger 155 transports the partially coated wood fibers to the post-treatment manifold 160. The inclusion of post-treatment processing provides consistent coating of the wood fiber. Thereafter, the wood fiber 540 (now thoroughly coated) is transported on-the conveyor 535 for final use or packaging.

FIG. 2 is a schematic illustration of a horizontal grinder for coating and grinding wood fibers according to one embodiment of the invention. Referring to FIG. 2, the wood fiber 110 is loaded by the machine 120 onto the feed table 301. The feed table 301 acts as a conveyor belt to transport the wood fiber 110 to the manifold 135 for coating. The hold down roller 305 is positioned to regulate the volume of material entering into the grinding mill 150. In a preferred embodiment, the manifold 135 is placed immediately below the hold down roller 305. Wood fibers pass over the manifold and are coated in the area 140 prior to entering the inlet of the grinding mill.

In situations where certain wood fiber particles may be too large for a particular application, the grinding mill 150 is positioned to receive the particles immediately after they are coated. The grinding mill 150 includes cutting teeth 225 and a cutting edge 235. As the grinding mill 150 rotates, cutting teeth 225 force the wood fiber particles 110 against the cutting edge 235 to reduce the particle size. The cutting screen 230 is positioned below the grinding mill 150 to sieve wood particles. Varying the size of the openings in the screen 230 for a particular application provides wood fibers of the desired size particulate. Wood particles too large to sieve through the screen 230 are retained in the grinding mill 150, reintroduced by cutting teeth 225, and re-ground against the cutting edge 235 in subsequent rotations.

In the embodiment of FIG. 2, the post-treatment manifold 160 provides a coating to the fresh cut facets of the wood fiber particles 310 created by the grinding mill 150. Notably, the wood fibers being treated by the post-treatment manifold 160 include the fresh cut uncolored wood fiber 310 as well as the previously coated wood fiber as coated by the manifold 135.

FIG. 3A schematically illustrates the coating process according to one embodiment of the invention. Referring to FIG. 3A, the wood fiber 110 travels in a direction as indicated by 303. The wood fiber is directed over the manifold 135, which is preferably fastened to the tub floor 111 with thru-bolted mounting hardware 420. The sides 325 of the manifold 135 are sloped to allow material to roll over the top of the manifold without being or creating an obstruction. The coating material 555, for example foam, is delivered to the manifold 135 by one or more hoses 510 and injected through one or more discharge ports 405 of the manifold 135. The discharge ports 405 are aimed toward the grinding mill 150. The wood fiber 110 is coated in the coloring area 140 and fed to the grinding mill 150 where the cutting tooth 225 grinds the particles against the cutting edge 235 producing smaller wood fiber particles. Fresh cut and uncolored fiber particles 310 are added to the particles sieved through the cutting screen 230 and transported by the conveyor belt 320.

Although not shown in the embodiment of FIG. 3A, the grinding mill 150 optionally has several cutting teeth 225 attached thereto for continuous grinding. It should also be noted that the embodiment of the invention is not limited to a grinding mill and that other devices for solid particle size reduction can be utilized without departing from the spirit of the invention.

In the embodiment of FIG. 3B, the post-treatment manifold 160 is positioned above the conveyor 535 to provide coating to the fresh cut facets of the wood fiber particles 310 created by the grinding mill 150. Notably, the wood fibers being treated by the post-treatment manifold 160 include fresh cut uncolored wood fiber 310 (shown in FIG. 3A) as well as the previously coated wood fiber as coated by the manifold 135. The wood fiber 540 (now thoroughly coated) is then preferably transported on the conveyor 535 for final use or packaging.

FIG. 4A-1 and FIG. 4A-2 are schematic representations of a manifold shown in its isolation and elevation views. The manifold 400 is shown to have discharge ports 405 arranged on one side and inlet ports 410 from the underside along with a provision for mounting hardware 403 to secure the base of the manifold to the host machinery. Colorant or other coating material is supplied to the inlet ports 410 and dispensed onto the substrate through the discharge ports 405. The sides 425 of the manifold 400 are sloped to allow material to roll over the top 430 of the manifold 400 without being or creating an obstruction.

FIG. 4B shows an armor-plated manifold 400 secured to the base 111 of a revolving tub (or grinding tub) with several bolts 403. FIG. 4B shows the relative size of an exemplary manifold 400 as compared with common construction objects. The top 430 and one of the sloped sides 425 of the manifold 400 are visible as well.

FIG. 4C shows the injection ports 410 to a manifold 400 as viewed from the underside of the tub grinder floor 111. Particularly, FIG. 4C depicts four flexible hoses 510 that supply colorant or other coating material to the inlet ports 410 of the armor-plated manifold 400.

The principles of the invention can be implemented with devices from different manufacturers. For example, tub grinders from the following suppliers can be used: Models 950, 1000, 1100, 1200XL, 1300, 1400, 1500, 3600, 4600, 5600, 6600 or 7600 grinders by Morbark, of Winn, Mich. Other tub grinders may be utilized, such as those sold by Diamond-Z Manufacturing of Caldwell, Id., Duratech Industries, International, of Jamestown, N.D., Hogzilla Grinder by CW Manufacturing, of Sabetha, Kans., Jones Manufacturing, Precision Huskey Corp, of Leeds, Ala., Vermeer Manufacturing Company, Inc., Pella, Iowa, Peterson Pacific of Eugene, Ore., Bandit Industries of Remus, Mich., and others. The novel embodiments disclosed herein are particularly advantageous in that the delivery system can be attached to the inside floor of a tub grinder to supply FlashFoam™ dispersion as well as aqueous dispersions.

Advantages of the novel method and apparatus disclosed herein (and variations thereof) over the conventional methods will be readily apparent to those skilled in the art. For example, the apparatus according to some embodiments of the invention enable treating mulch with any color or other coating with only one pass through the tub grinder resulting in significant efficiency and cost savings while eliminating the need for expensive colorizing plants. Upon treatment, the coated mulch is dry and colorfast, enabling producers to immediately utilize the processed mulch.

Moreover, the colorants do not require special handling needed with the standard dry products and can be delivered directly to the mulch, producing vibrant, long-lasting colors. Unlike other color products, the manifold disclosed herein does not spill, blow away or leach colorant into the ground and cause environmental concerns. Further, since treatment can be done onsite, the embodiments yield substantial savings on labor, processing and curing times, and transportation and storage cost.

Although examples are described in which the surface coating applied to the fiber is a colorant, the apparatus and method described above may be used to treat the fiber with any of a wide variety of materials, such as any of the materials described in co pending U.S. patent application Ser. No. 10/405,046, filed on Mar. 31, 2003, and published as Published patent application No. US20030213168A1 which is incorporated by reference herein. These may include, for example, other treatments such as dyes or pigments, oils that enhance the appearance, fragrance and/or insect repellency of the landscape material, insecticides, fungicides, and wood preservatives.

For example, in one embodiment, the colorant is received from a foam injection system (not shown) coupled to a mixing bin (not shown) containing a foaming source (e.g. water plus surfactant), an air compressor fluidly connected to a foam tank. Alternatively, the carrier and surfactant may be in separate tanks which are fluidly connected to the foam injection system. Exemplary foaming systems may include the WizTech FlashFoam™ P-60 and P-45 systems, available from Wizard Technologies, Toms River, N.J.

In a preferred embodiment, a treatment is combined with a foaming agent and a solvent to form a landscaping composition. The landscaping composition is then foamed to form a delivery medium for delivering the treatment to the wood fiber. In this embodiment, the treatment manifold treats the wood fiber with the treatment using the delivery medium.

Accordingly, it is to be understood that the embodiments of the invention herein described are merely illustrative of the application of the principles of the invention. Reference herein to details of the illustrated embodiments is not intended to limit the scope of the claims, which themselves recite those features regarded as essential to the invention.

Claims

1. A method of treating a plurality of wood fibers, comprising the steps of: a) introducing the wood fibers into a revolving tub; b) transporting the wood fibers to a first treatment manifold, wherein the first treatment manifold is located within the revolving tub and comprises at least one inlet port to receive a first treatment and at least one discharge port to apply the first treatment to the wood fibers; and c) treating the wood fibers with the first treatment using the first treatment manifold.

2. The method of claim 1, wherein the first treatment manifold is mounted to a floor of the revolving tub.

3. The method of claim 1, further comprising the steps of: d) transporting the wood fibers to a second treatment manifold; and e) treating the wood fibers with a second treatment using the second treatment manifold.

4. The method of claim 1, further comprising the step of grinding the wood fibers to a smaller nominal size.

5. The method of claim 4, further comprising the steps of: d) transporting the wood fibers to a second treatment manifold; and e) treating the wood fibers with a second treatment using the second treatment manifold.

6. The method of claim 1, further comprising the step of delivering a material to be used to treat the wood fibers to the first treatment manifold.

7. The method of claim 1, wherein the treatment comprises a colorant.

8. The method of claim 1, wherein the treatment is provided as a foam.

9. The method of claim 1 further comprising, prior to step (c), the steps of: d) combining the first treatment, a foaming agent, and a solvent to form a landscaping composition; and e) foaming the landscaping composition to form a delivery medium for delivering the first treatment to the wood fibers.

10. An apparatus for treating a plurality of wood fibers, comprising: a) a revolving tub; and b) a first treatment manifold mounted to the revolving tub, the first treatment manifold comprising at least one inlet port to receive a first treatment and at least one discharge port to apply the first treatment to the wood fibers.

11. The apparatus of claim 10, wherein the first treatment manifold is mounted to a floor of the revolving tub.

12. The apparatus of claim 10, wherein the first treatment manifold has sloped sides for allowing the wood fibers to roll over the first treatment manifold.

13. The apparatus of claim 10, further comprising a grinding machine comprising at least one tooth to grind the wood fibers into a plurality of smaller pieces.

14. The apparatus of claim 13, wherein the grinding machine is a grinding mill mounted to a floor of the revolving tub.

15. The apparatus of claim 14, wherein the discharge port is aimed toward the grinding mill.

16. The apparatus of claim 13, wherein the grinding machine further comprises a cutting screen, with openings sized to match a desired particulate size for wood fibers particles.

17. The apparatus of claim 13, further comprising a second treatment manifold in a second treatment area for treating the wood fibers with a second treatment, the second treatment manifold comprising at least one inlet port to receive the second treatment and at least one discharge port to apply the second treatment to the wood fibers; wherein the second treatment manifold treats the wood fibers after the wood fibers have been ground in the grinding machine.

18. The apparatus of claim 10, further comprising an engine coupled to the revolving tub.

19. The apparatus of claim 10, further comprising a transportable carrier, wherein the revolving tub is mounted on the transportable carrier.

20. The apparatus of claim 10, wherein the treatment comprises a colorant.

21. The apparatus of claim 10, wherein the treatment is provided as a foam.

22. The apparatus of claim 10, wherein the treatment is provided as a mist.

23. The apparatus of claim 10, wherein the treatment is provided in water.

24. The apparatus of claim 10, wherein the treatment is selected from the group consisting of: a) at least one dye; b) at least one pigment; c) at least one oil; d) at least one fragrance; e) at least one insect repellent; f) at least one insecticide; g) at least one fungicide; h) at least one wood preservative; and i) any combination of (a) through (h).

25. A method of treating a plurality of wood fibers, comprising the steps of: a) introducing the wood fibers onto a feed table; b) conveying the wood fibers along the feed table to a first treatment manifold, wherein the first treatment manifold comprises at least one inlet port to receive a first treatment and at least one discharge port to apply the first treatment to the wood fibers; c) treating the wood fibers with the first treatment using the first treatment manifold; and d) grinding the wood fibers in a grinding mill; wherein the wood fibers travel from the feed table over the manifold and into the grinding mill.