U.S. patent application number 10/448867 was filed with the patent office on 2003-12-04 for protector for chemically treated wooden utility pole and surrounding environment.
Invention is credited to Docter, Lloyd W..
Application Number | 20030221390 10/448867 |
Document ID | / |
Family ID | 30000440 |
Filed Date | 2003-12-04 |
United States Patent
Application |
20030221390 |
Kind Code |
A1 |
Docter, Lloyd W. |
December 4, 2003 |
Protector for chemically treated wooden utility pole and
surrounding environment
Abstract
The invention provides a utility pole that comprises an upper
end and a lower end, with the lower end having a butt end. The butt
end of the pole is encased in a substantially non-corrodible
metallic cladding, that is formed from a sheet of the metal, so
that the cladding protects the buried end of the pole from attack
by microorganisms in the surrounding soil, when the pole end is
buried. Further, the metallic cladding substantially prevents
migration of any biocidal chemicals from the pole into the
surrounding environment. In certain embodiments, the metallic
cladding may also be connected, through a ground conductor, to form
an electrical grounding means for the pole.
Inventors: |
Docter, Lloyd W.; (Tacoma,
WA) |
Correspondence
Address: |
STOEL RIVES LLP
900 SW FIFTH AVENUE
SUITE 2600
PORTLAND
OR
97204
US
|
Family ID: |
30000440 |
Appl. No.: |
10/448867 |
Filed: |
May 29, 2003 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
60385112 |
May 30, 2002 |
|
|
|
Current U.S.
Class: |
52/835 |
Current CPC
Class: |
E04H 12/2292
20130101 |
Class at
Publication: |
52/736.4 |
International
Class: |
E04C 003/30 |
Claims
1. A utility pole comprising: (a) an upper end and a lower end, the
lower end comprising a butt end; and (b) a substantially non
corrodible, snug fitting, metal cladding, the cladding surrounding
the butt end of the pole; wherein, when the butt end of the pole is
buried, the metal cladding substantially prevents migration of
chemicals from the pole into surroundings, and the metallic
cladding protects the butt end of the pole from attack by
microorganisms.
2. The utility pole of claim 1, wherein the metallic cladding
comprises copper or tin.
3. The pole of claim 1, wherein the metallic cladding has a
thickness ranging from about 0.025 mm to about 6.35 mm.
4. The pole of claim 2, wherein the cladding comprises copper, and
the cladding has a thickness from about 0.025 mm to about 6.35
mm.
5. The pole of claim 4, wherein the cladding is in the range from
about 0.275 to about 0.55 mm thick.
6. The pole of claim 1, further comprising a grounding element
extending from the upper end of the pole to the cladding so that
the cladding is an electrical ground for the pole.
7. A utility pole comprising: (a) an upper end and a lower end, the
lower end comprising a butt end; and (b) a snug fitting, metal
cladding comprising copper or tin, the cladding having a thickness
in the range from about 0.025 mm to about 6.35 mm, the cladding
surrounding the butt end of the pole; and (c) a grounding element
extending from the upper end of the pole to the cladding so that
the cladding is an electrical ground for the pole; wherein, when
the butt end of the pole is buried, the metal cladding
substantially prevents migration of chemicals from the pole into
surroundings, and the metallic cladding protects the butt end of
the pole from attack by microorganisms.
8. The pole of claim 7, wherein the cladding comprises copper.
9. The pole of claim 7, wherein the cladding comprises tin.
10. A utility pole comprising: (a) an upper end and a lower end,
the lower end comprising a butt end; and (b) a substantially non
corrodible, snug fitting, metal cladding, the cladding surrounding
the butt end of the pole, the cladding of sufficient thickness to
retain integrity over an expected lifespan of the pole; wherein,
when the butt end of the pole is buried, the metal cladding
substantially prevents migration of chemicals from the pole into
surroundings, and the metallic cladding protects the butt end of
the pole from attack by microorganisms in soil.
11. The pole of claim 10, wherein the metal comprises copper or
tin.
12. The pole of claim 10, further comprising a grounding element
extending from the upper end of the pole to the cladding so that
the cladding is an electrical ground for the pole.
13. The pole of claim 10, wherein the metallic cladding comprises
copper and the thickness of the cladding is in the range about
0.025 mm to about 6.35 mm
Description
RELATED APPLICATIONS
[0001] This application claims priority from U.S. application
Serial No. 60/385,112 filed May 30, 2002.
COPYRIGHT NOTICE
[0002] .COPYRGT. 2003 McFarland Cascade, Inc. Tacoma Washington. A
portion of the disclosure of this patent document contains material
which is subject to copyright protection. The copyright owner has
no objection to the facsimile reproduction by anyone of the patent
document or the patent disclosure, as it appears in the Patent and
Trademark Office patent file or records, but otherwise reserves all
copyright rights whatsoever. 37 CFR .sctn.1.71 (d).
TECHNICAL FIELD
[0003] This invention relates to the fields of utility poles used
to support electrical and telecommunication lines, and also to the
protection of the environment, when these poles are treated with a
leachable chemical compound. In particular examples, portions of
chemically treated wooden utility poles that are to be buried are
provided with a partial casing to protect the wood, prevent
migration of chemicals from the wood into the environment, and to
provide the possibility of being used as an electrical grounding
means.
BACKGROUND OF THE INVENTION
[0004] A modern industrial society requires a reliable electrical
supply, and also a reliable means of telecommunication. Typically,
electrical supply is by means of electrical cables, that are either
run underground or supported overhead on utility poles. Similarly,
telecommunications cables are either underground, or supported on
utility poles, frequently the same poles that carry the electrical
power supply cables. These utility poles can be made from a variety
of materials, including concrete, steel, and wood. The use of
wooden poles continues to be a standard, and literally millions of
these poles are used throughout North America.
[0005] Wooden utility poles are subject to deterioration in the
environment through contact with moist earth that harbors
microorganisms that attack and cause the wood to rot or otherwise
deteriorate. In order to prevent such premature deterioration,
wooden utility poles are commonly treated with chemicals. These
chemicals are biocides, intended to kill those microorganisms that
are likely to attack the wood, and are also potentially toxic to
humans in sufficiently high dosage. However, while these chemicals
have proved to be effective in prolonging the useful life of
utility poles, they may also pose an environmental hazard in that
there is a possibility that biocidal chemicals would migrate from
the wood into the surrounding earth. As a consequence, it would be
desirable to find ways preventing the leaching of biocidal
chemicals from the wood into the environment.
SUMMARY OF THE INVENTION
[0006] The invention provides a utility pole that comprises an
upper end and a lower end, with the lower end having a butt end.
The butt end of the pole, the portion of the pole that is to be
buried, is covered with a substantially non-corrodible metallic
cladding, that is formed from a sheet of the metal, so that the
cladding protects the butt end of the pole from attack by
microorganisms in the surrounding soil. Further, the metallic
cladding substantially prevents migration of any biocidal chemicals
from the pole into the surrounding environment. In certain
embodiments, the metallic cladding may also be connected, through a
ground conductor, to form an electrical grounding means.
[0007] Additional aspects and advantages of this invention will be
apparent from the following detailed description of preferred
embodiments, which proceeds with reference to the accompanying
drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0008] FIG. 1 is a schematic diagram of an embodiment of the
invention illustrating a utility pole equipped with a substantially
non-corrodible metallic cladding at its butt end;
[0009] FIG. 2 is an enlarged view of the butt end of the utility
pole of FIG. 1;
[0010] FIG. 3 is a cross-sectional view of the butt end of the pole
of FIG. 2;
[0011] FIG. 4 is a schematic diagram illustrating an embodiment of
the invention wherein the non-corrodible metallic cladding is
electrically connected to form an electrical ground;
[0012] FIG. 5 is a cross section through FIG. 4 at 5-5, as shown;
and
[0013] FIG. 6 is a partial side view of an embodiment of the
invention showing a utility pole, with butt end buried in the
earth, and with multiple sheets of cladding of a non corrodible
metal.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
[0014] In accordance with the invention, utility poles, especially
wooden utility poles, are provided with a casing or cladding that
surrounds the butt end of the pole to reduce or prevent attack from
agents in the environment, such as microbes, fungi, moisture, and
the like. Further, the casing substantially prevents any migration
of biocidal chemicals from the utility pole to the environment, by
providing a barrier.
[0015] Preferably, the metal used in the cladding that surrounds
and encases the butt end of the pole should be substantially
non-corrodible. The term "substantially non-corrodible" means that
when the metal is placed in the environment in which the pole butt
end is buried, namely in the earth, the metal does not corrode
through in a time frame that should be within the expected lifespan
of the pole. However, the metal may be subject to formation of a
thin film (for example, and oxidation film) on its surface,
localized etching, and other surface deterioration, without a
significant degree of perforation through the cladding during the
reasonably expected lifetime of the utility pole. It should also be
understood that the metallic cladding should be of a sufficient
thickness to prevent through corrosion, as discussed below, since
metal thickness also effects the ability of the cladding to retain
its integrity for the duration for the lifespan of the pole.
[0016] The cladding, in accordance with an embodiment of the
invention, may cover the butt end of the pole and extend upward
along the length of the pole, to the point of penetration of the
pole into the earth, or beyond. In other embodiments, the cladding
may not extend along the entire submerged or buried portion of the
utility pole. Preferably, the cladding does not encapsulate or seal
off the lower sawn off end of the pole, which is exposed to prevent
or reduce wood degradation.
[0017] To the extent that the cladding covers buried surface area
of the pole, that would normally be in close contact with the
environment, the cladding acts as a shield between the environment
and the buried pole portion. Thus, the cladding potentially
prevents migration of biocidal treatment chemicals, impregnated in
the wooden utility pole, from the pole into the environment.
[0018] The term "substantially prevents migration of chemicals"
means that the migration of chemicals is reduced by at least about
50% relative to the rate of migration without the cladding around
the butt end of the utility pole. Clearly, 100% cessation of
chemical migration may ordinarily not be preventable because of
some moisture seepage between the pole and the cladding, and
communication of this seeped water back into the environment. Thus,
in accordance with the invention, there is a substantial prevention
of migration, but not always a total prevention of migration.
[0019] The invention may be better understood with reference to the
appended figures. Referring to FIGS. 1, 2 and 3, a utility pole 10
has an upper end 12 to which is affixed structure 14 for supporting
utility and/or electrical cables. The pole 10 has a lower end 16,
that is submerged or buried within the earth 18. A butt end 22 of
the pole 10 is clad with a sheet of non-corrodible metal 20. The
metal sheath extends along a length h of the pole. The length h may
extend from the buried butt end 22 of the pole to the point at
which the pole 10 enters the earth 18, and beyond, as shown in FIG.
1.
[0020] FIG. 6 shows another embodiment in which the cladding 20 is
applied in multiple layers, on above the other, with some overlap
at adjacent edges possible, so that narrower strips of metal can be
used rather than one broad strip that extends from pole base to
point of earth entry or exit.
[0021] Referring to FIGS. 4, and 5, a ground wire 24 on the support
structure 14 is connected by a ground connector 26 to the cladding
20. This connection of the cladding 20 to the ground wire 24
effectively permits the cladding 20 to act as an electrical
grounding means for the utility pole 10. More than one layer of
cladding can be used, as shown in FIG. 5, for example. Clearly, the
cladding 20 is useful, even without connection through the ground
conductor to the ground wire to act as an electrical grounding
means, as explained above.
[0022] The preferred cladding material is copper, tin, or alloys of
these metals, but other non corrodible metals may also be used.
Copper is particularly preferred. Copper is useful not only because
it is non corrodible, as defined herein, but also because it is a
good electrical conductor. So, it allows use of the cladding as an
electrical grounding element.
[0023] The cladding should preferably be of a sufficient thickness
to retain its integrity under environmental conditions for the
expected lifespan of the utility pole, which is typically around
100 years for treated wooden poles. This will eliminate the need
for costly retrofits at later stages. In the case of a copper
cladding, the cladding should have a thickness in the range from
about 0.0216 inches (0.55 mm) to about 0.0108 inches (0.275 mm) for
a lifespan of 100 years, and preferably about 0.0108 inches (0.275
mm). Of course, other cladding thickness may be used for other
desired useful lives of the pole, for example thickness of in the
range from about 0.001 (0.0254), to about 0.250 (6.35) inches (mm)
and the like within or outside this range.
[0024] It will be obvious to those having skill in the art that
many changes may be made to the details of the above-described
embodiments without departing from the underlying principles of the
invention. The scope of the present invention should, therefore, be
determined only by the following claims.
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