U.S. patent application number 10/206160 was filed with the patent office on 2003-01-30 for structural members fabricated from waste materials and method of making the same.
Invention is credited to Leon, Joseph.
Application Number | 20030019946 10/206160 |
Document ID | / |
Family ID | 23196413 |
Filed Date | 2003-01-30 |
United States Patent
Application |
20030019946 |
Kind Code |
A1 |
Leon, Joseph |
January 30, 2003 |
Structural members fabricated from waste materials and method of
making the same
Abstract
The structural member and fabrication thereof may be formed by
mixing wood products chemically treated for durability and
thermoplastics products. The fabrication process may included
processing the products to a desired particle size; mixing the
particles; processing the mixture in a high intensity processor and
then processing the mixture in an extruder to obtain a molten state
for forming the structural element in a mold. It is emphasized that
this abstract is provided to comply with the rules requiring an
abstract that will allow a search or other reader to quickly
ascertain the subject matter of the technical disclosure. It is
submitted with the understanding that it will not be used to
interpret or limit the scope or meaning of the claims.
Inventors: |
Leon, Joseph; (Bakersfield,
CA) |
Correspondence
Address: |
Law Offices of DENNIS W. BEECH
Landmark Building - Newland Center
19900 Beach Blvd., Suite C-2
Huntington Beach
CA
92648
US
|
Family ID: |
23196413 |
Appl. No.: |
10/206160 |
Filed: |
July 25, 2002 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
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60309039 |
Jul 30, 2001 |
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Current U.S.
Class: |
238/84 |
Current CPC
Class: |
E01B 3/10 20130101; E01B
3/44 20130101 |
Class at
Publication: |
238/84 |
International
Class: |
E01B 003/00 |
Claims
I claim:
1. A method for manufacture of structural members from existing
wood and thermoplastic products and materials, comprising the steps
of: selecting a wood product that has been chemically treated for
durability; processing said wood product in a grinder to form
chemically treated wood particles; selecting a thermoplastic and
processing said thermoplastic in a chipper to form thermoplastic
particles; mixing said chemically treated wood particles and said
thermoplastic particles in a mixer to form a mixture; processing
said mixture in a high intensity processor to further mix and
preheat said mixture; processing said mixture in an extruder to
compress and heat said mixture to form a molten mixture; placing
said molten mixture into a mold for forming a structural member;
and removing from said mold after cooling has occurred said
structural member.
2. The method as in claim 1 wherein said wood product chemical
treatment is creosote oil.
3. The method as in claim 1 wherein said wood product is selected
from the group of a wood railroad tie, a wood utility pole and a
wood sign post.
4. The method as in claim 1 wherein said thermoplastic is selected
from the group of a polyethylene and a polypropylene.
5. The method as in claim 1 wherein said chemically treated wood
particles are processed to a size to be a diameter of approximately
one to forty millimeters.
6. The method as in claim 1 wherein said thermoplastic particles
are processed to a size to be a diameter of approximately one to
twenty millimeters.
7. The method as in claim 1 wherein processing said thermoplastic
is performed in a densifier.
8. The method as in claim 1 wherein said wood product is a waste
material.
9. The method as in claim 1 wherein said thermoplastic is a waste
material.
10. The method as in claim 1 wherein said mixture is comprised of
approximately ten to seventy percent by weight of said
thermoplastic and approximately thirty to ninety percent by weight
of said wood product.
11. The method as in claim 1 wherein processing is said high
intensity processor further reduces the size of said thermoplastic
particles and said chemically treated wood particles.
12. The method as in claim 1 wherein said extruder heats said
mixture to approximately a temperature of 150 degrees Centigrade to
230 degrees Centigrade.
13. The method as in claim 1 further comprising the step of adding
a fire retardant substance during the mixing step.
14. A structural member produced according to the method of claim
1.
15. A method for manufacture of structural members from existing
wood and thermoplastic products and materials, comprising the steps
of: selecting a wood product that has been chemically treated for
durability; processing said wood product in a grinder to form
chemically treated wood particles of a diameter of approximately
one to forty millimeters; selecting a thermoplastic and processing
said thermoplastic in a chipper to form thermoplastic particles of
a diameter of approximately one to twenty millimeters; mixing said
chemically treated wood particles and said thermoplastic particles
in a mixer to form a mixtures comprised of approximately ten to
seventy percent by weight of said thermoplastic and approximately
thirty to ninety percent by weight of said wood product; processing
said mixture in a high intensity processor to further mix and
preheat said mixture; processing said mixture in an extruder to
compress and heat said mixture to approximately a temperature of
150 degrees Centigrade to 230 degrees Centigrade to form a molten
mixture; placing said molten mixture into a mold for forming a
structural member; and removing from said mold after cooling has
occurred said structural member.
16. A structural member produced according to the method of claim
15.
17. A structural member comprising: a mixture of a wood product
chemically treated for durability and a thermoplastic; wherein said
mixture is comprised of ten to seventy percent by weight of said
thermoplastic and thirty to ninety percent by weight of said wood
product; and wherein said mixture has been compressed and heated to
allow said thermoplastic to penetrate in said wood product having
molds therein.
18. The structural member as in claim 17 wherein said wood products
are chemically treated with creosote oil.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application claims the benefit of U.S. Provisional
Application Serial No. 60/309,039 filed Jul. 30, 2001.
BACKGROUND OF THE INVENTION
[0002] The present invention generally relates to materials used
for the fabrication of structural members. More specifically, the
present invention relates to processing chemically treated wood
products and wood waste and fabricating such products and waste,
along with waste thermoplastic, into useful structural members.
These chemically treated wood products, wood waste and waste
thermoplastic otherwise must be disposed, which is expensive and/or
difficult.
[0003] Many wooden materials used as structural members must be
chemically treated to render the wood suitable for the particular
use or purpose. For example, wooden poles, posts and cross-members
used for supporting utility lines, railroad cross-ties, and signs
are usually pressure treated with creosote oil, which acts as a
fungicide, germicide and insecticide to protect those members from
various forms of fungal, bacterial and insect attack. Other
chemicals are used to accomplish these purposes.
[0004] The benefits of chemically treated wooden structural members
are well documented. For example, the life expectancy for untreated
railroad ties installed during 1900 was four to six years. However,
the life expectancy for ties treated with coal tar creosote is
approximately thirty years. Nevertheless, because of the tremendous
amount of railroad track in service, railroads in the United States
replace millions of railroad ties every year. The life expectancy
of a railroad tie remains relatively short because the ties are
subject to substantial compressional and impact stresses as train
cars travel over the rails. Because the pressure treatment does not
penetrate the entire matrix of a wooden structural member, cracking
of the outside structure can provide a pathway for water and
microorganisms to invade untreated wood within the tie. The wood
ultimately rots and deteriorates under train traffic. These same
types of problems exist for other creosote treated wooden members
which, according to the particular use, experience various types of
environmental exposure and are subject to dynamic loading and the
related stresses. Because these members have a limited life span,
there is an ongoing demand for these structural members for
application in both new and existing installations. The demand is
aggravated by diminishing natural resources, including the hardwood
from which most of these products are manufactured.
[0005] In addition to a supply shortage, an additional problem
exists regarding chemically treated wooden members. Because a
tremendous number of these members must be replaced each year,
disposal is required for the removed members. However, because of
the chemical treatment of these members with creosote oil and other
substances that have been classified as hazardous substances,
disposal of these items can be difficult and expensive. Various
solutions have been proposed for disposal of the chemically treated
wood as opposed to landfill disposal. Railroad crossties are
commonly used for building retaining walls, raised gardens and
other landscaping projects. Another proposed solution is to reduce
the wooden members to mulch like material and use the material as
fuel in wood fired boilers to generate electricity. There have also
been proposals for recycling the wooden members to be reused for
the same purpose. While these proposals seemingly solve two
problems at once, to date none have widely been accepted. Part of
the problem is that transporting the used materials for processing
is itself prohibitively expensive. Regarding recycling members, the
known processes result in a laminated final product that raises
concerns about the integrity of the member at the layer
boundaries.
[0006] In addition to disposing of chemically treated wooden
structures, disposal of plastic structures and plastic waste is an
ongoing problem. Plastic structures and plastic waste can be bulky
and consume valuable landfill space. Although the recycling of
plastics has been increasing, depending upon the particular
application, some plastics are not acceptable.
[0007] The disclosed structural members solve the above problems.
The disclosed process for manufacturing the structural members may
be located on site or located immediately adjacent to a railroad
siding, thereby eliminating or greatly reducing the transportation
costs of other methods. The disclosed structural members may have
no layering but rather have a uniform matrix. The disclosed process
uses recycled thermoplastics to fabricate the disclosed structural
members, thereby having the added benefit of providing an
alternative used for plastics which might otherwise be
discarded.
SUMMARY OF THE INVENTION
[0008] The present invention may be directed to a structural member
which may be manufactured from previously chemically treated wood
or other waste wood, which has the structural integrity to be used
as a structural member for utility lines, railroads, pier
construction, and other applications where strength may be
required, where there may be exposure to bacterial and insect
attack, and where long life may be necessary because, among other
reasons, repair expense may be prohibitive because of the expense
of taking the particular system out of service to effect the
repair.
[0009] The present invention further comprises a method of
producing the disclosed structural members from chemically treated
wood which otherwise must be disposed of at considerable expense.
Such treated wood may include wood that has been painted, laminated
wood, Formica, utility poles and cross-members, railroad ties, etc.
The disclosed method may further comprise the processing of the
members being replaced, thereby eliminating or reducing the
disposal costs for the old structural members. The method of
processing may be configured to be mobile, thereby allowing the
structural members to be manufactured onsite and reducing or
eliminating handling and transportation expenses for the materials
being replaced. The disclosed method may further comprise the use
of recycled thermoplastic, the thermoplastic acting as both a
binder and an encapsulator. Both polyethylene and/or polypropylene,
as well as other thermoplastics may be used in the process.
[0010] These and other features, aspects and advantages of the
present invention will become better understood with reference to
the following drawings, description and claims.
BRIEF DESCRIPTION OF THE DRAWINGS
[0011] FIG. 1 illustrates a flow diagram outlining the disclosed
method and shows a resulting product according to an embodiment of
the invention.
DETAILED DESCRIPTION
[0012] The following detailed description represents the best
currently contemplated modes for carrying out the invention. The
description is not to be taken in a limiting sense, but is made
merely for the purpose of illustrating the general principles of
the invention.
[0013] Referring now to FIG. 1, waste wood, such as
chemically-treated railroad ties utility poles, etc., may be placed
within a grinder 10 or chipper to obtain a chip size ranging from
one to forty millimeters in diameter, the grinder 10 or chipper may
be of the type which may be portable and towable. The ideal chip
size may range from ten to forty millimeters. One suitable grinder
may be a CBI Magnum Force Series 6000 Hz Hog manufactured by
Continental Bio-Mass Industries, Inc.
[0014] Waste thermoplastic, including polyethylene and/or
polypylene or other readily available thermoplastic may also be
chipped to obtain a chip or particle size ranging from one to
twenty millimeters in diameter. Thermoplastics soften when heated,
but harden when cooled. Plastic drums, containers, and plastic
structures may be processed through a chipper 20 machine to obtain
the desired chip or particle size. Depending upon the
thermoplastic, instead of a chipper, a densifyer may be used to
cause the plastic to consolidate into the desired particle size.
For example, plastic shopping bags cannot be chipped and may
instead be processed with a densifyer to consolidate the plastic
and obtain plastic particles. The thermoplastic chips may act as
binder and as an encapsilator of the wood chips contained within
the matrix of the new structural member.
[0015] After the desired range of chip sizes has been achieved for
the waste wood and the waste thermoplastic, the plastic chips and
wood chips may be mixed together, such as in a conventional drum
mixer 30. An acceptable mix ratio may be ten to seventy
percent-by-weight plastic corresponding to thirty to ninety
percent-by-weight wood chips.
[0016] The resulting mixture from the mixer 30 may then be fed into
a high-speed blender also known as a high intensity processor 40.
An acceptable high-speed blender may be that manufactured by Lex
Technologies, Inc. of Ontario, Canada. The high-speed blender may
have high-speed blades that may impart a shearing force to the
mixture that imparts friction to the wood and plastic chips, which
may thoroughly mix the wood and plastic chips together and heat up
the chip mixture by the friction of the blades. The heated
thermoplastic chips, becoming softer, fill the interstitial space
between the wood chips, forming a binding agent for adjacent wood
chips. In addition the high-speed blender may further reduce the
size of the wood chips and plastic chips, resulting in a more
consolidated and cohesive mixture.
[0017] After the desired consistency is achieved with the
high-speed blender, the mixture may be fed into an extruder 50 that
may be of the ram or single or twin screw type having the
capability to heat the barrel. The extruder 50 compresses the
mixture, thereby heating the mixture to a temperature in a range
from 150 degrees to 275 degrees Centigrade. A molten mixture may be
pumped or pulled from the extruder 50 into molds that are specially
prepared according to the specific size and shape of the member
required. Following cooling, the plastic-wood members may be
removed from the molds, inspected, stored for curing and then
installed as desired. The new structural members may have a uniform
dispersion of creosote oil or other substance that were used for
treating the source wood, showing a further benefit of the
disclosed invention. As discussed above, because pressure treatment
is unable to reach the core of the wooden members with the treating
substance, wooden members may be vulnerable to fungal, bacterial
and insect attack if the inner untreated core is exposed through
fracturing or cracking. However, the members formed through the
disclosed process may take advantage of any prior treatment
compounds used in the source wood and equally dispense those
compounds throughout the new structure. If desired, additional
treatment chemicals may be added during the mixing stage to achieve
desired properties. For example, in addition to creosote oil, it
may be desirable to add fire retardant or other substances.
[0018] While the invention has been particularly shown and
described with respect to the illustrated embodiments thereof, it
will be understood by those skilled in the art that the foregoing
and other changes in form and details may be made therein without
departing from the spirit and scope of the invention.
* * * * *