U.S. patent application number 13/167870 was filed with the patent office on 2011-10-13 for continuously manufactured colored metallic products and method of manufacture of such products.
This patent application is currently assigned to ALLIED TUBE AND CONDUIT CORPORATION. Invention is credited to William Boyce, James Florek, James Hays.
Application Number | 20110250365 13/167870 |
Document ID | / |
Family ID | 34590708 |
Filed Date | 2011-10-13 |
United States Patent
Application |
20110250365 |
Kind Code |
A1 |
Florek; James ; et
al. |
October 13, 2011 |
Continuously Manufactured Colored Metallic Products and Method of
Manufacture of Such Products
Abstract
Metallic tube, pipe and conduit are made in a continuous process
that includes a zinc galvanization stage, a first passivation
stage, a second passivation stage and a third passivation stage. A
colorant is added to the tube, pipe or conduit during the
continuous manufacturing process, and the colorant imparts the
appearance of a color, such as red. The continuous movement of the
tube, pipe or conduit is not halted during normal operation of the
tube, pipe or conduit manufacturing and coloring process.
Inventors: |
Florek; James; (New Lenox,
IL) ; Hays; James; (Orland Park, IL) ; Boyce;
William; (Villa Park, IL) |
Assignee: |
ALLIED TUBE AND CONDUIT
CORPORATION
Harvey
IL
|
Family ID: |
34590708 |
Appl. No.: |
13/167870 |
Filed: |
June 24, 2011 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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10702625 |
Nov 6, 2003 |
7989028 |
|
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13167870 |
|
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60455933 |
Mar 19, 2003 |
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Current U.S.
Class: |
427/514 ;
427/239 |
Current CPC
Class: |
C23C 28/023 20130101;
C23C 28/3225 20130101; C23C 28/322 20130101; C23C 28/00 20130101;
F16L 9/02 20130101; B21C 37/06 20130101; C23C 28/3455 20130101;
B21C 37/09 20130101; B21C 37/30 20130101; B21C 37/0807 20130101;
Y10T 428/12486 20150115; C23C 28/025 20130101; C23C 2/26 20130101;
Y10T 428/12799 20150115; Y10T 428/12847 20150115; F16L 2201/60
20130101 |
Class at
Publication: |
427/514 ;
427/239 |
International
Class: |
B05D 7/22 20060101
B05D007/22; B05D 3/06 20060101 B05D003/06 |
Claims
1. A method for imparting a colorant to a metallic surface during a
continuous manufacturing process, comprising: moving a metal tube
in a continuous manufacturing process; applying a coating to an
inner surface of the metal tube; galvanizing an outer surface of
the metal tube; applying a chromate coating over the galvanized
surface, the chromate coating including a colorant; and applying a
clear organic polymer coating over the chromate coating.
2. The method of claim 1, wherein the colorant is a liquid
colorant.
3. The method of claim 1, wherein the movement of a steel tube in
the continuous manufacturing process has a rate of speed of more
than about six hundred feet per minute.
4. The method of claim 3, wherein the movement of a steel tube in
the continuous manufacturing process has a rate of speed of more
than about one thousand feet per minute.
5. The method of claim 1, further comprising curing the colorant
using ultraviolet light curing.
6. The method of claim 1, wherein the coating is a paint.
7. The method of claim 1, wherein the coating is a corrosion
resistant coating.
8. The method of claim 1, wherein the coating is an antibacterial
coating.
9. A method for imparting a colorant to a metallic surface during a
continuous manufacturing process, comprising: moving a metal tube
in a continuous manufacturing process; applying a corrosion
resistant coating to an inner surface of the metal tube;
galvanizing an outer surface of the metal tube; applying a first
passivation layer over the galvanized outer surface, the first
passivation layer including chromium and a colorant; and applying a
clear organic polymer coating over the first passivation layer.
10. The method of claim 9, wherein the colorant is selected from
the list consisting of pigment, powder, liquid, ink and identifying
lacquer.
11. The method of claim 9, wherein the movement of a steel tube in
the continuous manufacturing process has a rate of speed of more
than about one thousand feet per minute.
12. The method of claim 9, further comprising curing the colorant
using ultraviolet light curing.
13. The method of claim 9, wherein the continuous manufacturing
process occurs at a substantially constant rate of speed.
14. The method of claim 9, wherein the colorant comprises a
pigment, a powder, a liquid ink, or an identifying lacquer.
15. A method for imparting a colorant to a metallic surface during
a continuous manufacturing process, comprising: moving a metallic
tube in a continuous manufacturing process; applying a coating to
an inner surface of the metallic tube; galvanizing an outer surface
of the metallic tube; applying first and second passivation layers
over the galvanized outer surface; and providing a colorant on or
in the first passivation layer; wherein the first passivation layer
includes chromate, and the second passivation layer comprises a
clear organic polymer coating.
16. The method of claim 15, wherein a third passivation layer is
applied over the second passivation layer before the second and
third passivation layers set or fully dry so that said second and
third passivation layers intermingle to provide increased
interconnectivity there between.
17. The method of claim 16, wherein at least one of the first,
second and third passivation layers contains said colorant, and
said passivation layer containing said colorant is applied as a
pattern.
18. The method of claim 15, wherein the coating is an antibacterial
coating.
19. The method of claim 15, wherein the coating is a corrosion
resistant coating.
20. The method of claim 15, wherein the colorant comprises a
pigment, a powder, a liquid ink, or an identifying lacquer.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application is a continuation of U.S. Non-provisional
patent application Ser. No. 10/702,625, filed Nov. 6, 2003, which
is a non-provisional of U.S. Provisional Application Ser. No.
60/455,933, filed Mar. 19, 2003, the entirety of which applications
are incorporated by reference herein.
FIELD OF INVENTION
[0002] The present invention relates to shaped metallic products
such as steel pipe, tube or conduit made in a continuous
manufacturing process that incorporates coloration as a part of the
continuous process and relates to the method of manufacture of such
metallic products.
BACKGROUND OF THE INVENTION
[0003] The present invention concerns shaped metallic products such
as steel pipe, tube or conduit made in a continuous manufacturing
process that, along with forming the metallic shaped product, adds
color to the outer surface of the product. Metallic products such
as tubes, pipes and conduit containing the appearance of color are
extremely useful. Colored tubes may be used to designate the
purpose of the tube. For example, red-colored tube can be used to
contain the electrical wires for fire detection and response
systems; blue-colored tube can be used to contain drinking water or
coolant; yellow-colored tube can be used to contain and transport
hot water. The addition of color to tube assists in installation
and inspection of the tube and aids in easy identification of tube
that is used for a particular purpose.
[0004] Previously, manufacture of colored tube generally involved a
non-continuous process. In previous processes, metal strip was
formed into tube in one process and then removed from the forming
process. Color was then added to the tube in a different process.
The coloration process occurred at a separate location and a
separate time from the tube manufacturing process. The process for
making the tube and the process for adding coloration, in the
previous processes, were not part of the same continuous process.
The use of separate processes for making and adding color to tube
has the drawbacks of decreasing the efficiency and increasing the
cost of the process of creating colored tube, and preventing the
colorant from being added to the tube as part of the tube
manufacturing process
[0005] In the current invention, the addition of color to the tube,
pipe or conduit occurs in the same continuous process as that in
which the tube, pipe or conduit is formed. The coloration process
is part of the continuous manufacturing process. The tube, pipe or
conduit does not cease moving and is not cut until after the
coloration process in the current invention. It is understood that
while the word "tube" is frequently used in this description, the
description applies equally to pipe, conduit and other metallic
cylinders and columns as well as tube. In addition, while the
specific examples mentioned in the preferred embodiments frequently
refer to tube, the present invention includes pipe, conduit,
columns, cylinders, squares, rectangles, solids and non-solid
shapes (such as bars, beams, strips or other non-solid shapes) as
well as tube.
[0006] The current invention has many benefits, including increased
efficiency, decreased need for space for equipment, decreased labor
and decreased difficulties involved in transferring formed and cut
tube to a coloration station. The current invention provides for
clearly visible tube systems, eases and saves time with
installation and inspection, and assists with future upgrades and
maintenance of tube systems. The current invention decreases the
labor and material costs associated with painting and creates
greater system integrity.
BRIEF SUMMARY OF THE INVENTION
[0007] The present invention concerns shaped metallic products such
as steel tube made in a continuous process in which the addition of
color to the tube is a part of the continuous manufacturing
process, and concerns the process for making such tube.
BRIEF DESCRIPTION OF THE DRAWINGS
[0008] FIG. 1 is a block diagram of one embodiment of the
manufacturing process for a metallic tube of the present
invention.
[0009] FIG. 2 is a depiction of one embodiment of a finished
metallic tube of the present invention, showing layers of the
finished tube cut away.
[0010] Before the embodiments of the invention are explained in
detail, it is to be understood that the invention is not limited in
its application to the details of the method, or arrangement of the
components set forth in the following description or illustrated in
the drawings. The invention is capable of other embodiments and of
being practiced or being carried out in various ways. Also, it is
to be understood that the phraseology and terminology used herein
are for the purpose of description and should not be regarded as
limiting. The use of "including" and "comprising" and variations
thereof is meant to encompass the items listed thereafter and
equivalents thereof as well as additional items and equivalents
thereof.
DETAILED DESCRIPTION OF THE INVENTION
[0011] The following paragraphs describe a few of the embodiments
of the current invention. In one embodiment, coiled steel is first
obtained from an external or internal source. The coiled steel
typically is flat, cold rolled or hot rolled carbon steel. If the
steel is hot rolled, typically it also is pickled to remove the
scale, and then oiled and recoiled. The coiled steel typically
comes from one of numerous industry sources as flat rolls of steel
weighing in excess of 1,000 lbs. The rolls typically are more than
three feet wide upon receipt and contain flat rolls of steel of
approximately 2,000-3,500 feet in length.
[0012] The coiled steel is slit to obtain an appropriate width
strip for the outer diameter or shape of the final product that
will be manufactured. After being slit, the coiled steel is drawn
off the roll and may be placed into an accumulating station. The
accumulating station connects the ends of flat strips of steel from
different coils into a continuous flat strip.
[0013] The steel is then subject to a cleaning process to remove
oil and other contaminants. In the cleaning process, the steel is
typically subjected to a series of alkaline cleaners, high-pressure
water and a squeegee blow-off stage.
[0014] As shown in FIG. 1, in one embodiment of the invention,
after being cleaned the steel [10] begins a continuous
manufacturing process. In the first stage [12] of the continuous
process, the steel is formed. In this stage, the steel is rolled or
molded from its flat shape and into the desired shape. Common
desired shapes include tubes, squares, rectangles and non-solid
shapes.
[0015] After the steel is formed to the desired shape, it is
subjected to a welding process which forms the steel into a
continuous surface. If the desired shape is a non-solid, the
welding process is not used. The welding process typically creates
a seam or weld [31] where the steel has been connected to itself.
Welding may be done by any common method, such as natural
resistance, electrical resistance and high frequency welding.
[0016] In some embodiments, before the steel reaches the welding
point, a paint lance may be inserted into the interior of the
steel. If the steel has been formed into a tube, the paint lance is
inserted inside the tube. The paint lance has a paint head that is
down-stream from the insertion point of the lance. By the time the
steel has progressed to the point where the paint head is located,
it has cooled sufficiently to allow paint to be applied to the
inner surface of the tube. The paint lance then sprays paint, a
coating, such as an antibacterial coating, a corrosion-resistance
material or some other covering onto the interior of the steel.
[0017] In some embodiments, after being welded, the outer surface
of the steel is smoothed [32]. Again, if the desired shape is a
non-solid and no welding process is used, there is no need to
employ a smoothing process and therefore this smoothing stage is
avoided. Frequently, a roughened or bumpy surface exists at the
site of the weld after the welding process. The smoothing process,
which may involve wire brushing, removes the rough or bumpy
areas.
[0018] In some embodiments, after being smoothed, the steel is
again cleaned [34] with a typical cleaner, such as an alkaline
cleaner. The steel is then subjected to an acid bath [36], which
contains an acidic substance such as hydrochloric acid, which
removes oxide from the steel surface. The steel is then rinsed [38]
with a rinsing agent such as water and subjected to pre-heating
[50]. In the pre-heating stage, the temperature of the steel is
raised to the point that it may be subjected to rapid
galvanization.
[0019] After pre-heating, the steel is galvanized [52]. In some
embodiments, the galvanization can be accomplished by any method
that is standard for the industry. One of these methods involves
passing the steel through a zinc pot. The zinc pot contains high
levels of molten zinc. When the steel passes through the molten
zinc, some of the zinc may react with and adhere to the steel. The
method by which such galvanization takes place is well-understood
in the industry.
[0020] After galvanization, the steel is subjected to a blow-off
stage [54], which removes excess zinc through blown air, vibration
or contact removal. The steel then passes through a liquid
quenching stage [56] in some embodiments, which lowers the
temperature of the steel and sets the zinc into the steel. Common
quenching methods include passing the tube through a bath of
temperate water. After being quenched, the steel is sized [70]. In
this stage the steel is subjected to sizers, such as rollers and
molders, which form the steel into the exact desired outer diameter
or shape.
[0021] Different outer diameters and shapes are used for different
applications. Tube with an outer diameter of a maximum of 1.740,
1.510, 1.163, 0.922 or 0.706 inches is useful for applications that
benefit from tube with a smaller diameter, such as carrying small
amounts of electrical wire, water or compressed air. Tube with an
outer diameter of a minimum of 2.197, 2.875, 3.5, 4.0 or 4.5 inches
is useful for applications that benefit from tube with a larger
diameter, such as carrying larger amounts of electrical wire, water
or compressed air. Different gauges of tube are involved in the
present invention. In one embodiment, the final manufactured tube
has a gauge approximately between 8 and 18.
[0022] In the embodiment of the invention shown in FIG. 1, the
steel is then subjected to passivation. In the passivation stage
[72], a barrier is bonded (through physical and/or chemical
bonding) on the outer zinc surface. Passivation can be accomplished
through a reactive process, a non-reactive process or a combination
of reactive and non-reactive processing. The passivation barrier
may decrease interactions between outside moisture or air and the
zinc layer or the underlying steel and may form a coating. The
barrier may limit white rust or other contamination occurring on
the surface of the zinc. The barrier also can provide corrosion
resistance. One method of passivating the zinc is to pass the
zinc-coated steel through a bath that includes hexavalent chromium.
Other passivation methods, including the use of non-chromium
coatings, also can be used.
[0023] In the embodiment shown in FIG. 1, after the first
passivation stage, the steel may be subjected to a second
passivation stage [74]. In the second passivation stage, a second
barrier is placed over and bonded (through physical and/or chemical
bonding) to the first barrier. The second passivation stage can
employ reactive processes, non-reactive processes or a combination
of reactive and non-reactive processes. The second passivation
barrier may form a coating and may assist with corrosion resistance
and inhibit air and moisture from interacting with the first
barrier, the zinc layer and/or the steel.
[0024] In the embodiment shown in FIG. 1, after the second
passivation stage, the steel may be subjected to a third
passivation stage [76]. In the third passivation stage, a third
barrier is placed over and bonded (through physical and/or chemical
bonding) to the second barrier. The passivating substance used in
the third passivation stage may mix or intermingle with the
passivating substance in the second passivation stage prior to
either substance fully setting or drying. The resulting bonds that
are formed create increased interconnectivity between the second
and third passivation stage. In other embodiments (e.g., where the
distance between the second passivation stage and the third
passivation stage is large or where the second passivation
substance(s) dries quickly), the third passivation substance does
not mix or intermingle with the substance over which it is
applied.
[0025] The third passivation stage can employ reactive processes,
non-reactive processes or a combination of reactive and
non-reactive processes. The third passivation barrier may form a
coating and may assist with corrosion resistance and may inhibit
air and moisture from interacting with the second barrier, the
first barrier, the zinc layer and/or the steel. Additional
passivation stages beyond the third passivation stage, placing
additional barriers over the metallic substrate, also may be
used.
[0026] In one embodiment, the method used for the passivation
stage(s) involves passing the tube through a bath of the
passivating substance. Another embodiment involves a flood and wipe
method that involves passing the steel tube through a bath that
includes a lacquer or other passivating substance, and excess
passivating substance is then wiped from the tube as it nears the
end of the passivation stage. In another embodiment, the method
used in the passivation stage(s) involves a vacuum coating method
that involves passing the steel through a vacuum chamber and
spraying the passivating substance, such as a lacquer, on the
steel. Excess substance is then vacuumed off the exterior of the
tube. Additional embodiments of the present invention involve
application of passivation substances through other methods, such
as conventional spray, electrostatic spray, fluidized bed, and a
combination of two or more of these methods.
[0027] The passivation substances and passivation barriers may form
complete barriers or may form only partial barriers. In some
embodiments, the passivation substances are applied as uniform
coatings that fully coat the underlying layer or tube. In other
embodiments, the passivation substances are applied as patterns and
only partially coat the underlying layer or tube. In these later
embodiments, the partial coating of the passivation substance does
not provide a uniform barrier between the outside air and the
underlying layers and tube, and the ability of the substance to
assist with corrosion resistance and inhibit air and moisture from
interacting with the underlying layers and steel may be further
limited or eliminated altogether.
[0028] In one embodiment, the method used for application of the
passivation substance(s), especially in the third passivation
stage, involves spraying and curing or drying. The steel tube
passes through a spray station in which several nozzles spray the
passivation substance(s), in a liquid form, onto the exterior of
the pipe and underlying coatings. The nozzles are easily
adjustable. The size of the particle that leaves the nozzle can be
adjusted by adjusting the size of the nozzle orifice through which
the passivation substance passes. The volume of the flow of
material through the nozzle also can be adjusted. In some
embodiments, a nozzle orifice size of between approximately 0.01
and 0.02 inches is preferred and a nozzle orifice of approximately
0.015 inches more preferred. A decrease in the size of the particle
that is sprayed on the tube makes the coating on the tube more
even. Through this spraying method, a uniform amount of the
passivation substance(s) is applied to the exterior.
[0029] In another embodiment, the method used for application of
the passivation substance(s) especially in the third passivation
stage, involves a vacuum coating method. In this method, the steel
tube passes through a vacuum chamber. The passivating substance is
sprayed onto the steel while it is in the chamber. Excess substance
is then vacuumed off the exterior of the tube. Through the method
of vacuum coating, a substantially uniform amount of passivation
substance is applied to the exterior of the tube.
[0030] Numerous other passivation methods are common in the
industry for the passivation stage(s). Each of the passivation
methods described herein can be used for the first, second, third,
or subsequent passivation stages.
[0031] Substances involved in the passivation process include
urethanes, acrylic compounds or epoxies, which are often contained
in lacquers or powders, all of which are commonly available in the
market. These passivation substances may be solids, water based or
solvent based, and may be cured in standard manners, including
ultra violet light, induction, infrared, conventional, air and
electron beam curing. These passivation substances also may contain
polymer resins, organics, chromium or solvents. Where the
passivation substances contain organics, the coatings they form may
be referred to as organic coatings. These passivation substances
can contain materials such as chromium, sec butyl alcohol,
propylene glycol, propylene glycol n-propyl ether, 2-butoxy
ethanol, triethylamine and other materials. The passivation
substances form a bond, physical or chemical, with the layer
beneath them, and may or may not be involved in chemical reactions
with the underlying layer(s), the underlying zinc or the underlying
metal. In some embodiments the passivation substances may contain
no less than 60% water. In some embodiments the passivation
substances may contain no more than 20% solids. The level of solids
and/or level of water in the passivation substances can assist the
ease of the application of the passivation substances and can
promote uniform coating.
[0032] In one embodiment, the passivation substance used in one or
more stages includes a colorant. This colorant may be any substance
that imparts the appearance of a color, shade, value or hue to the
outer surface of the metal, such as a pigment, powder, liquid, ink
or identifying lacquer. Numerous colors can be used with the
colorant, including red, green, yellow, blue, orange, purple,
brown, white, black and other colors. This colorant remains with
the tube or other shape after the continuous manufacturing process
is completed.
[0033] Care must be taken when using a flood and wipe method to
apply colorant. This method can cause streaking of the color and
make the pipe visually unappealing if not closely monitored. In the
flood and wipe method, the wipe cloth may need to be changed
frequently (every 10 minutes) to avoid streaking. Applying colorant
as part of a spraying process, as described above, assists in
eliminating such streaking. Applying colorant in the spraying
process also applies a thinner color than is applied in the vacuum
coating process. This thinner color is more easily applied in a
manner that keeps the color somewhat transparent.
[0034] The passivation stages and passivation substances previously
described each are optional. In one embodiment of the present
invention, three or more passivation stages are used. In another
embodiment, only one passivation stage is used. In another
embodiment, there is no passivation stage.
[0035] The present invention also encompasses colorant being
applied to the tube or other shape at one or more of several
different phases in the continuous manufacturing process. In one
embodiment, colorant is added in the third passivation stage. If an
earlier passivation substance includes chromium, the colorant added
to the third passivation stage may need to be compatible with
chromium. In other embodiments, the colorant is added in the first
or second passivation stage. In another embodiment, the colorant is
added in the sole passivation stage. In another embodiment, the
colorant is added as part of the galvanization stage. Colorant
added in the galvanization stage must maintain its integrity at the
temperature of the galvanization stage. In other embodiments, color
is added before the first passivation stage, after the last
passivation stage, or in several passivation and/or non-passivation
stages.
[0036] One method of adding a colorant to the metal during the
galvanization stage involves including a colorant in the quench
material that is applied to the tube after it leaves the
galvanization stage. Such colorants are readily available and
include pigments, powders, liquids, inks or identifying lacquers.
The quench material used may be water or some other solvent
(organic or inorganic), and the colorant is combined with this
material prior to the quenching of the steel. The quench material,
including the colorant, forms a bond with the galvanized tube and
imparts the appearance of color to the tube.
[0037] In another embodiment of the present invention, colorant is
added before the first passivation stage or after the final
passivation stage. Prior to the first passivation stage or after
the final passivation stage, an additional substance, such as a
coating, paint, resin, powder or lacquer, is applied to all or a
portion of the tube. This substance contains a colorant, which
imparts the appearance of color to the tube. This substance can be
applied to the tube through numerous well-known processes such as
spray (e.g., electrostatic spray or conventional spray), fluidized
bed, powder or vacuum coating. The colorant may be applied to the
entire tube, or may be applied to a portion of the tube in a
pattern, such as a stripe, spiral, text, dots or other pattern.
[0038] After leaving the third passivation stage, in some
embodiments, the tube enters a drying stage [80]. In the drying
stage the final passivation substance is cured and/or dried to the
point that the tube can be touched by a bounce limiter or other
device after leaving the drying stage without rubbing off a portion
of the passivation substance.
[0039] In some embodiments the drying stage can take the form of an
induction box [82] followed by a drying tunnel [84]. The induction
box [82] may consist of a pipe of non-magnetic material that is
approximately 3-7 feet long and wider than the tube being
manufactured. A coil is wrapped around the pipe and a current is
passed through the coil creating a magnetic field and a heating
area for objects that pass within the pipe. The tube then passes
through the pipe and is heated. An air source also is connected to
the pipe to pass air through the heating area. In some embodiments
the air moves at a rate of approximately 1500-2500 cfm. The air is
generally approximately 20-50 degrees Fahrenheit warmer than
ambient air. Tube moving at a rate of 600 ft./min. passes through
an induction box with a length of approximately 3-7 feet in
approximately 0.3-0.7 seconds.
[0040] In some embodiments the induction box is followed by a dry
tunnel [84]. The dry tunnel [84] is a pipe that that is wider than
the tube being manufactured and is approximately 6-10 feet long. An
air source is connected to this pipe, which passes air through the
pipe at a rate of approximately 1500-2500 cfm. The air is generally
approximately 20-50 degrees Fahrenheit warmer than ambient air. The
tube being manufactured passes inside this pipe and is contacted by
the blowing air. Tube moving at a rate of 600 ft./min. passes
through a dry tunnel with a length of approximately 6-10 feet in
approximately 0.6-1 second. In some embodiments, when the tube
leaves the dry tunnel, the third passivation substance has dried to
the point that the tube can be touched without marring the surface.
In these embodiments, the third passivation substance dries or
cures within approximately between 0.9 and 1.7 seconds after it is
applied to the tube.
[0041] In some embodiments, the steel may be subject to additional
heating, cooling and/or drying. In some embodiments, bounce
limiters [86] are installed after the drying stage(s). At the end
of the manufacturing process, the steel is cut to the desired
length with a blade or other cutting device [102]. The blade may
include a sharp device that swings through the tube at desired
intervals. The cutting process may cause the steel to bounce
somewhat. The cutting blade may cause the steel to slow its
forwarded advancement slightly when the steel is cut. When the
forward advancement is slowed, the steel bounces in a vertical
direction to maintain its continuous advancement. This bouncing can
have deleterious effects on the outer surfaces of the steel and can
negatively impact the continuous manufacturing process. To limit
this bouncing, bounce limiters [86] are installed in the continuous
manufacturing process to be available to contact the steel after it
has been dried and before the cutting stage.
[0042] Bounce limiters in some embodiments diminish the amplitude
of bouncing of the tube caused by cutting and limit the propagation
of large bounce amplitudes backward along the continuous
manufacturing process. In some embodiments bounce limiters can
include bounce rolls that are made of polyethylene, polypropylene,
other plastic, metal or other formative substance. Bounce limiters
can incorporate springs or other shock mechanisms that will assist
in at least partially absorbing and dissipating the bounce of the
tube. These springs or shock mechanisms are optional and the bounce
limiters can function without them in some embodiments. The bounce
limiters may be connected to a stationary material that does not
move in a vertical direction.
[0043] Bounce limiters can be placed underneath the tube to limit
the tube from traveling downward from its manufacturing path.
Bounce limiters also can be placed above the tube to limit the tube
from altering its manufacturing path and moving upward. In one
embodiment, bounce limiters have no spring mechanism and take the
form of a pair of cylindrical rolls that roll with the tube when
the tube is in contact with them and prevent the tube from moving
in a downward direction. Bounce limiter pairs may be horizontally
staggered so that one bounce limiter is further downstream in the
manufacturing process than the other bounce limiter of the pair.
Due to the dryness of the tube after the drying stage(s) the bounce
limiters have very limited effect on the appearance or
functionality of the outer coating on the tube.
[0044] After passing through the bounce limiters, the steel is cut
in the cutting stage [100] that includes a blade or other cutting
device [102]. The blade may be a metal object that swings through
the tube very quickly. The blade also may be incorporated into a
mechanism that briefly attaches to the tube prior to cutting,
travels with the tube during cutting and then detaches from the
tube. The blade may include a sharp device that swings through the
tube at desired intervals.
[0045] The present invention imparts color to galvanized tube in
some embodiments. Due to its galvanized nature, the tube may be
rippled with markings referred to in the industry as galvanization
ripples, air rings or water quench rings. The present invention
imparts color to the tube regardless of this rippling. The present
invention also imparts color to the tube regardless of whether the
tube has been buffed or polished or otherwise smoothed.
[0046] During the continuous manufacturing process, in one
embodiment, the steel moves at a substantially constant rate of
speed. This rate is preferably more than one hundred feet per
minute, more preferably more than three hundred feet per minute,
even more preferably more than six hundred feet per minute, and
most preferably more than one thousand feet per minute. The steel
moves from the forming stage through the final passivating stage
and to the cutting stage in a continuous process. The steel is not
stopped at any normal operating time, but continuously moves
through each stage of the entire process.
[0047] An additional embodiment of the present invention involves
the use of pre-galvanized steel in the continuous manufacturing
process. In this embodiment, rather than beginning the process with
cold or hot rolled steel that has been cut and cleaned, but not
galvanized, the process begins with steel that already has been
subject to galvanization. In this embodiment, the steel is
pre-galvanized before it begins the continuous manufacturing
process.
[0048] In one embodiment of the present invention, a flat strip of
pre-galvanized steel is subjected to the continuous forming process
and the welding process as described above. After being welded, the
tube or other solid shape of pre-galvanized steel will have an area
at the weld in which the galvanization has been removed. The zinc
galvanization is replaced on this area through numerous methods
well known in the art, such as by arc flash or vaporization of zinc
wire at the site of the weld. Through this process, additional zinc
is placed or sprayed onto the weld area, thereby replacing the zinc
that was removed during the welding process. If the desired end
shape is a non-solid, the welding and zinc galvanization
replacement stages are not used.
[0049] After the galvanization replacement stage, this tube or
other shape may go through one or more of the stages described
above, including the passivation stages. A colorant also may be
added to this tube or other shape through the methods described
above.
[0050] In another embodiment of the present invention, the steel is
never galvanized. The galvanization stage described above may be
replaced with a galvalum or galvanealing stage. Galvalum and
galvanealing processes are well known in the art. The galvanization
stage also may be replaced with a process that hardens and
strengthens the metal and lowers its ductility.
[0051] FIG. 2 shows one embodiment of the present invention with
layers of steel tube cut away. The first and innermost layer is the
steel itself [110]. The next layer is a zinc galvanization layer
[112]. The next layer is a first passivation layer [114]. A second
passivation layer [116] also may be included over the first
passivation layer. A third passivation layer [118] also may be
included over the second passivation layer. The first, second and
third passivation layers may contain any or all of the passivation
substances described above and/or chromium.
[0052] The processes described above may be used to create
different types of tube, including Electrical Metallic Tubing,
Intermediate Metal Conduit and tube that meets the specifications
set forth by standardization organizations, such as the
Underwriters Laboratories, Inc. and American National Standards
Institute, including UL 797, UL 1242, ANSI C80.3 and ANSI C80.6,
each of which is enclosed and incorporated by reference in this
application. In a preferred embodiment, the process described above
is used to make Electrical Metallic Tubing.
[0053] In one embodiment, tube made from the process described
above may be used to enclose and protect electrical wire. Such
electrical wire is placed within the tube subsequent to manufacture
of the tube and installed with a corresponding electrical system.
This tube also can be used to house other substances such as
liquids, water for sprinkler systems or gases.
[0054] After the tube has been manufactured, it may be installed.
Different colors of the tube can be installed for different
applications. In one embodiment, to install this tube, colored tube
made from the continuous process described herein is placed in or
near a building. Electrical wires that are part of or related to
the building's fire alarm detection and/or response systems are
then placed within the tube. These wires may be connected to the
building's central computing system or systems. One method of
placing the wires in the tube is to blow a lead string through the
tube. This string is attached to the wires and by pulling the
string from one end of the tube, the wires are pulled through the
tube. Other methods of placing the wires in the tube are well
understood in the industry.
[0055] The electrical wires within the colored tube are easily
locatable in this embodiment. For fire alarm detection or response
systems, tube with a red color can be used. By locating the
red-colored tubes, one has located the electrical wires for the
fire alarm detection and response system.
[0056] This same installation method can be used for other
applications with tube containing different colors. Tube made using
the process described herein and containing another color, such as
green or yellow, may be installed in or near a building. Electrical
wire for other applications, such as computing applications,
security, lighting, motion tracking, ventilation, air conditioning,
and heating is then placed within the tube and may be connected to
the building's central computing or data collection system.
[0057] In this manner, the wire for these applications can be
easily located in times of need by locating tube with the
appropriate color. Additional systems, such as sprinkler systems or
gas systems containing gases such as oxygen or compressed air, can
be incorporated into tube made according to the invention described
herein and containing a different color, such as blue, orange, or
other color, and that has been installed in or near a building.
[0058] A particular building may contain two or more separately
colored tubes. Each separately colored tube contains wires or other
substances for distinct applications. For example, a particular
building may contain red tube for fire detection and treatment
wires and substances, green tube for computing wires, yellow tube
for electrical wires related to lighting, blue tube for a water or
a sprinkler system, and orange tube for motion tracking devices.
The wires or other substances in one or more of the tubes may be
connected to the building's central computing system or systems.
This central system may consist of one or more computers or
computing devices. This central system may be used to collect the
information provided by and coordinate the activity of the
substances in each separately colored tube.
[0059] While the invention has been described with respect to
specific examples and embodiments including presently preferred
modes of carrying out the invention, those skilled in the art will
appreciate that there are numerous variations and permutations of
the above described substances and methods that fall within the
spirit and scope of the invention.
* * * * *