Note: Descriptions are shown in the official language in which they were submitted.
CA 02481696 2004-09-16
TITLE OF THE INVENTION:
Method And Apparatus To Reduce The Width Of A Slot Or Opening In A Pipe, Tube
Or Other Object.
FIELD OF THE INVENTION
This invention relates to a method and to an apparatus to reduce the width of
a slot or
opening in a pipe, tube or other object, and in one aspect to a method and an
apparatus
to reduce the width of slots in tubular liners for well bore holes.
IO
CA 02481696 2004-09-16
BACKGROUND OF THE INVENTION
Slotted metal pipes, or tubulars as they are often known, have been used for a
considerable length of time in oil, gas and water wells as a means to limit
the amount
of sand or debris allowed to enter the tubular as oil, gas or water is drawn
in from
surrounding underground formations. The slotted tubulars effectively act as a
liner and
screening mechanism to permit the desired fluid to be drawn into the tubular
for
extraction while excluding sand, rock and other particles. Tubular liners must
have slots
that are sufficiently small in width to prevent particulate matter from
entering the pipe,
while maintaining sufficient structural integrity to withstand pressures to
which they
may be subjected in underground environments, particularly in wells having
horizontal
components.
The difficulty encountered with slotted tubulars is not so much in their use
but in their
method of manufacturing. The particular underground formation within which the
tubular is to be deployed will for the most part dictate a maximum slot width
that will
be acceptable. In oil and gas well applications, it is often the case that the
oil or gas
being targeted is located in formations comprised of fine sand particles. In
such
situations it is not unusual to require a slot width in the tubular of 0.010
of an inch, or
less. Unfortunately, conventional manufacturing equipment is rarely capable of
cutting
slots in tubulars effectively having a width less than 0.015 inches. As a
result,
2
CA 02481696 2004-09-16
manufacturers commonly subject slotted tubulars to a secondary seaming process
where
rollers are used to apply pressure to the tubular in the vicinity of the slot,
having the
result of narrowing the slot width at the exterior surface and forming a slot
with a
keystone, parabolic, or similar shaped profile.
A variety of different seaming methods have been proposed by others as a means
to
reduce the width of slots formed in tubulars through conventional mechanical
methods.
Such methods include those described under U.S. patent 6,112,570, dated
September 5,
2000; Canadian patent 2,183,032, dated July 17, 2001; and, Canadian patent
2,324,730,
dated August 12, 2003.
Although the seaming methods that have been used by others have been generally
successful, they also suffer from a number of inherent limitations. First, the
alignment
of seaming equipment with the slots or openings has proven to be difficult and
often
requires considerable operator effort and skill. To reduce the need for
precise alignment
of the seaming equipment with the slots or openings some have suggested
passing the
seaming equipment or rollers over the entire surface of the product in a
helical pattern.
While doing so may to a large degree alleviate alignment issues, it also
significantly
slows down the seaming process since the entire exterior surface of the
product must be
treated. Currently available methods also provide no mechanism for
continuously
checking the degree to which the width of the slots or openings have been
reduced, or
3
CA 02481696 2004-09-16
to accurately track instances where treated slots or openings do not meet
specifications.
Under existing methods, and with currently available equipment, the treated
products
are typically inspected manually and then manually sent back to the seaming
process if
it is determined that their slots are not within specified tolerances.
4
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CA 02481696 2004-09-16
SUMMARY OF THE INVENTION
The invention therefore provides a method and an apparatus to reduce the width
of a slot
or opening in a pipe, tube or other object that facilitates in the alignment
of seaming
equipment with the slots or openings in the pipe or object, alleviates the
need to
completely treat the exterior surface of the product to reduce slot width, and
that
analyzes and tracks instances where treated slots or openings do not meet
specification
so that such slots or openings can be automatically re-treated.
Accordingly, in one of its aspects the invention provides a method to reduce
the width
of a slot or opening in a pipe, the pipe having an outer surface and an inner
surface with
one or more slots or openings extending between its outer and inner surfaces,
the
method comprising the steps of reducing the width of one or more of said slots
through
treating the exterior surface of the pipe with one or more compression tools;
determining
the position of said one or more slots relative to the surface of the pipe;
following said
treatment of the exterior surface of said pipe with said one or more
compression tools
determining the width of said one or more slots in said pipe; generating a
signal
corresponding to the determined width and relative position of said one or
more slots
and directing said signal to a controller; with said controller comparing the
determined
width of said one or more slots with a pre-determined value and identifying
slots having
widths greater than said pre-determined value; and, causing the exterior
surface of said
5
CA 02481696 2004-09-16
pipe adjacent to said one or more slots having determined widths greater than
said pre-
determined value to be re-treated through causing at least one of said one or
more
compression tools to be moved to selectively contact the exterior surface of
said pipe
adjacent to said identified slots so as to selectively further reduce the
width of said slots.
In a further aspect the invention provides a method of reducing the width of a
slot or
opening in a pipe, the pipe having an outer surface and an inner surface with
one or
more slots or openings extending therebetween, the method comprising the steps
of
loading the pipe into a seaming machine, said seaming machine having one or
more
seaming heads, said one or more seaming heads and the pipe movable relative to
one
another, each of said one or mare seaming heads including one or more seaming
rollers
movable from a position where they contact the surface of said pipe to a
position where
they are free from contract with the surface of said pipe; using said one or
more seaming
rollers to treat the exterior surface of said pipe adjacent to said one or
more slots through
the application of a compressive force to the exterior surface of said pipe to
thereby
reduce the width of said slots; following said treatment of the exterior
surface of said
pipe with said one or more seaming rollers, determining the width of said one
or more
slots in said pipe and the position of said one or more slots relative to the
surface of said
pipe; generating a signal corresponding to the determined width and relative
position of
said one or more slots following said treatment of the exterior surface of the
pipe and
directing said signal to a controller, said controller operatively connected
to said one or
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CA 02481696 2004-09-16
more seaming rollers and controlling the position of said one or more seaming
rollers
relative to the surface of the pipe; with said controller comparing the
determined width
of said one or more slots to a pre-determined value and identifying slots
having a width
greater than said pre-determined value; and, causing said controller to move
one or more
of said seaming rollers into contact with the exterior surface of said pipe
adjacent to said
one or more slots having determined widths greateav than said pre-determined
value to
selectively and compressively treat the exterior surface of the pipe at
locations adjacent
to said slots having determined widths greater than said pre-determined value
and to
thereby selectively further reduce the width of said slots.
The invention also concerns an apparatus for reducing the width of a slot or
opening in
a pipe, the pipe having an outer surface and an inner surface with one or more
slots or
openings extending therebetween, the apparatus comprising one or more
compression
tools independently movable from a position where they are free from contact
with the
surface of said pipe to a position where they contact the pipe's exterior
surface and apply
a compressive force thereto, when compressed against the exterior surface of
said pipe
adjacent to one or more of said slots said one or more compression tools
reducing the
width of said one or more slots; at least one slot measurement device, when
activated
said slot measurement device determining both the width and the relative
position of one
or more of said slots following the reduction of the width of said one or more
slots, said
slot measurement device further generating a signal corresponding to the
determined
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CA 02481696 2004-09-16
width and relative position of said one or more slots; a controller, said
controller
receiving said generated signal and comparing the determined width of said one
or more
slots with a pre-determined value to identify slots having widths greater than
said pre-
determined value; and, means to cause one or more of said compression tools to
be
moved to selectively contact the surface of said pipe adjacent to slots having
determined
widths greater than said pre-determined value to selectively and further
reduce the width
of said slots.
In addition, the invention also concerns a method to reduce the width of a
slot or
opening in a pipe, the pipe having an outer surface and an inner surface with
one or
more slots or openings extending between its outer and inner surfaces, the
method
comprising the steps of determining the position of said one or more slots
relative to the
surface of the pipe; determining the width of said one or more slots in said
pipe;
generating a signal corresponding to the determined width and relative
position of said
1 S one or more slots and directing said signal to a controller; with said
controller
comparing the determined width of said one or more slots with a pre-determined
value
and identifying slots having widths greater than said pre-determined value;
and, with
said controller causing the exterior surface of said pipe adjacent to said one
or more slots
having determined widths greater than said pre-determined value to be treated
through
causing one or more compression tools to be moved to selectively contact the
exterior
surface of said pipe adjacent to said identified slots so as to selectively
reduce the width
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CA 02481696 2004-09-16
of said slots.
Further aspects and advantages of the invention will become apparent from the
following description taken together with the accompanying drawings.
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CA 02481696 2004-09-16
BRIEF DESCRIPTION OF THE DRAWINGS
For a better understanding of the present invention, and to show more clearly
how it may
be carried into effect, reference will now be made, by way of example, to the
accompanying drawings which show the preferred embodiments of the present
invention
in which:
Figure 1 is a side elevational view of a tubular element having slots formed
in its
exterior surface through conventional methods;
Figure 2 is a sectional view taken along the line 2 - 2 of Figure 1;
Figure 3 is view similar to Figure 2 wherein the slots of the tubular element
have been
treated such that their width has been reduced;
Figure 4 is an enlarged detailed view of one of the slots of Figure 3;
Figure S is a side elevational view of a portion of a seaming machine for
reducing the
width of a slot in a tubular element pursuant to one of the preferred
embodiments of the
present invention;
CA 02481696 2004-09-16
Figure 6 is a detailed side elevational view of one of the seaming heads of
the apparatus
shown in Figure 5;
Figure 7 is an end view of the seaming head of Figure 6 as viewed from
direction "A"
in Figure 6;
Figure 8 is an end view of the seaming head of Figure 6 as viewed from
direction "B"
in Figure 6; and,
Figure 9 is a detailed view of the seaming roller shown in Figure 8.
11
CA 02481696 2004-09-16
DESCRIPTION OF THE PREFERRED EMBODIMENT
The present invention may be embodied in a number of different forms. However,
the
specification and drawings that follow describe and disclose only some of the
specific
forms of the invention and are not intended to limit the scope of the
invention as defined
in the claims that follow.
It should be noted that the invention described herein may be practiced in
association
with a wide variety of different types, shapes and sizes of objects or
products having
slots, holes or openings within their outer surfaces. For illustration
purposes the specific
embodiments of the invention that are described below concern the use of the
invention
in connection with a slotted pipe or tubular member. Accordingly, pursuant to
one of
the preferred embodiments of the invention there is provided a pipe, tube, or
tubular
element 1 having an outer surface 2 and an inner surface 3 (see Figure 1 ).
Spaced about
the outer surface of tubular member 1 is a series of slots or openings 4,
having a width
5 and a length 6, that extend through the pipe's wall (see Figures 1 and 2).
Typically
slots 4 will be spaced about the surface of tubular member 1 in general
alignment with
the longitudinal axis of the tubular member, and in a repeating pattern.
However, it will
be appreciated by those skilled in the art that the method and apparatus
described herein
may be equally applied to tubular members having slots of different
orientations
12
CA 02481696 2004-09-16
positioned about the surface of the tubular element. The invention is also not
limited
to tubular members of any particular length, and may be used on relatively
short lengths
of pipe, elongated tubulars, or rolls of continuaus tubing. It should also be
appreciated
that the diameter of the tubulars may vary depending upon their end use. Where
the
tubulars are to be used as liners in oil, gas, or water wells, they would
typically have
lengths ranging from approximately 20 to approximately 45 feet, and diameters
from 2
to 123/4 inches.
The manner in which slots 4 are cut or formed within tubular member 1 is, for
the most
I O part, of minor consequence to the current method and apparatus for
reducing slot width.
Most commonly the slots will be created through the use of a mechanical
cutting tool
or milling machine, although more sophisticated equipment, including lasers
and water
jet equipment, could also be used. Regardless of how the slots are formed, the
basis for
the invention is a requirement that the width of the slots be reduced to less
than can be
currently achieved, either technically or economically, through the use of
conventional
cutting, milling or slotting equipment. Once the tubular members have been
slotted they
may then be subjected to the apparatus and process described herein in order
to reduce
the width of their slots to an acceptable and desired range.
13
CA 02481696 2004-09-16
The first step under the method of the present invention is to treat the
exterior surface
of pipe or tubular member 1 with one or more compression tools in order to
reduce the
width of slots 4. While a variety of different types of mechanical equipment
and
different methods may be used to reduce the width of the slots, in a preferred
embodiment of the invention the treatment of the exterior surface of the pipe
is carried
out with the assistance of a seaming machine 7. With reference to Figure 5,
seaming
machine 7 will in most instances have many of the same features as are
currently
available on similar devices, and may include one or more seaming heads 8
having
mounted thereon one or more compression tools 9. Typically the compression
tools
will include a seaming roller 10. As is known in the art, sweeping a roller
across the
surface of a pipe, while at the same time applying a compressive force to the
roller that
is transferred to the pipers surface, can cause the longitudinal peripheral
edges of slots
4 to be deformed, resulting in a partial closing or a reduction of the width
of the slots.
Provided that the pressure applied by the seaming rollers exceeds the yield
strength of
the material from which the pipe is formed, there will be a deformation of the
material
along the sides of the slots, causing a portion of the material to "flow"
under plastic
deformation into the slots thereby reducing their widths (See Figures 3 and
4). Of course
the amount and the degree by which the width of an individual slot is reduced
will be
the function of a variety of different factors; including, the amount of
compressive force
applied through seaming rollers 10, the material composition of the pipe, the
speed at
which the rollers are passed over the surface of the pipe, the alignment or
misalignment
14
CA 02481696 2004-09-16
of the rollers with the longitudinal axis of the slots, the temperature of the
pipe during
the treatment process, etc. Examples of currently available methods and
devices that
may used to reduce the width of a slot in a pipe may be found by reference to
U. S, patent
6,112,570, dated September 5, 2002; Canadian patent 2,324,730, dated August
12, 2003
S and Canadian patent 2,183,032, dated July 17, 2001.
With reference to Figure S, there is shown a relatively common form of seaming
machine 7 that has been modified in order to perform the method of the present
invention. Here, seaming machine 7 includes a head stock assembly 11, one or
more
pipe carriage assemblies 12 and, as indicated previously, one or more seaming
heads 8.
The primary purpose of the head stock assembly is to first feed the slotted
tubular
member into the seaming machine, and then to secondly rotate the tubular
during the
various stages of the seaming or treatment process. Although not specifically
shown in
Figure 5, head stock assembly 11 would typically include a series of linear
rollers or
bearings to facilitate the movement or loading of the tubular into the seaming
machine.
The head stock will also include a chuck that may be engaged about the
exterior surface
of the tubular to serve as both a means to hold the tubular and to impaxt
rotational
movement thereto. Typically one or more electric or hydraulic motors would be
utilized
to load the and rotate the tubular.
15
CA 02481696 2004-09-16
When the pipe or tubular is loaded into the seaming machine, one end will be
held by
head stock assembly 11 with the remainder of the tubular supported by one or
more
carnage assemblies 12. The carriage assembly serves the general purpose of
supporting
the pipe in the desired vertical and horizontal planes . As is shown in
Figures 6, 7 and
S 8, carriage assembly 12 will typically be comprised of a base 13 having
mounted thereon
a plurality of pipe supports 14 that support and permit rotational movement of
pipe or
tubular member 1. Pipe supports 14 may be rollers or may be fixed structures
that are
formed from material that provides reduced frictional resistance to the
relative
movement of the carriage assembly and the pipe. The base I3 of the carriage
assembly
would in most instances be mounted on a pair of linear rails 15 that are
aligned with the
longitudinal axis of the seaming machine. Rails 15 permit the base to be moved
in a
back and forth manner along the length of the machine while the seaming heads
remain
in a fixed position relative to the machine's frame 17. Linear movement of the
pipe and
the carriage assemblies may be accomplished through the use of a variety of
different
means or devices (not specif cally shown in the attached drawings), including
tempo
sonic hydraulic cylinders, pneumatic cylinders, ball screw drives, and
electric or
hydraulic drive systems (including servo drives).
It will be appreciated that relative longitudinal movement between the pipe
and the
~0 seaming heads is required but that such relative movement may be
accomplished in
more than more manner. Accordingly, in an alterr,~ate embodiment of the
seaming
if
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CA 02481696 2004-09-16
machine to that shown in the attached drawings, the pipe and the carriage
assemblies
may be fixed in position and the seaming heads may be moved in a back and
forth
manner along the length of the pipe.
With reference once again to Figures 6, 7 and 8, it will be noted that each of
the seaming
heads includes a frame assembly 16 secured to frame 17 of seaming machine 7.
The
seaming head frame assembly encompasses the pipe and the carriage assemblies
such
that the carriage assemblies and the tubular member may travel longitudinally
therethrough. One or more seaming rollers 10 are positioned on a roller holder
26 that
is slidably received within a guided channel 27 on a roller frame 18. Roller
frame 18
is itself slidably received on one or more generally horizontal rails 28
positioned on
frame assembly 16. Roller holder 26 is is movable in a generally vertical
direction
within guided channel 27 through the operation of ane or more cylinders 19.
Frame 18
is movable in a horizontal direction along rails 28 through the operation of
one or more
horizontal alignment cylinders 25. Horizontal alignment cylinders 25 permit
the
positioning of the seaming rollers to be adjusted where necessary in order to
ensure
proper alignment of the rollers with the slots. Since in most instances the
roller's path
will be approximately ~/s inch wide, proper alignment with the slots is
important when
utilizing a seaming machine of the type shown in Figures 6 through 8.
Cylinders 19 permit seaming rollers 10 to be moved from a position where they
are free
17
CA 02481696 2004-09-16
from contact with the surface of pipe or tubular member 1 to a position where
they
contact the pipe's exterior surface and apply a compressive force thereto.
Through
compressing rollers 10 against the surface of the pipe, and by moving the pipe
and the
carriage assemblies past the seaming heads (or by moving the seaming heads
along the
length of the pipe), the compressive force applied to the pipe by the seaming
rollers will
have a tendency to reduce the width of individual slots about which the
rollers are
positioned. As indicated previously, the amount by which the width of the
slots will be
reduced is a function of a variety of factors including the speed at which the
pipe is
moved past the rollers (or vice versa) and the compressive force applied by
the seaming
rollers. The amount of compressive force applied by the seaming rollers can be
adjusted
as necessary through operation of cylinders 19. An enlarged detailed view
showing the
contact between the seaming roller and the surface of pipe or tubular element
1 is
provided in Figure 9.
As shown in Figure 7, seaming head frame assembly 16 also preferably includes
a guide
or clamping roller 24 mounted on the opposite side of the seaming head from
the
seaming roller. Guide or clamping roller 24 serves the function of helping to
maintain
the pipe or tubular element in position on the carriage assemblies 12. Roller
24 also
helps to accommodate slight bends in the pipe by forcing the pipe into
alignment with
the seaming roller.
18
CA 02481696 2004-09-16
As indicated, a number of discreet and independently controllable seaming
heads 8 may
be positioned along the length of seaming machine 7. In the embodiment of the
apparatus shown in Figure 5 eight such heads are incorporated within the
seaming
machine, however, more or less than eight heads may be used depending upon the
S particular application at hand. Crenerally each of the seaming heads will be
identical
in structure, will perform the same function, and will be independently
controllable. The
amount of compressive force applied to the pipe's exterior surface can be
varied from
seaming head to seaming head, as desired. In addition, and as described in
more detail
below, in some instances the seaming rollers of specific heads may be forced
into
contact with the surface of the pipe to reduce the width of particular slots
while the
rollers of other heads may at the same time be retracted such that they do not
contact the
pipe's exterior surface.
For the most part, the slots that are formed in pipes or tubular members used
for
wellbore liners or similar purposes, are of a uniform length and arranged in
rows that are
generally paxallel to the longitudinal axis of the pipe (see Figure 1). A
variety of
different methods of moving or sweeping seaming rollers over the exterior
surface of
such a pipe or tubular member in order to reduce the width of the slots is
described in
the prior art. Such methods most commonly involve either aligning the seaming
rollers
with the slots and moving the pipe in a direction that maintains the alignment
of the
rollers with the slots, or causing the seaming roller to follow a generally
helical
19
CA 02481696 2004-09-16
sweeping path across the entirety of the pipe's exterior surface. In the
particular
embodiment of the apparatus shown in the attached drawings, the seaming
rollers are
first aligned with a row of slots, after which the tubular element is moved
longitudinally
through the seaming machine in order to reduce the width or "seam" that
particular row
of slots, Once the treatment of the row of slots has been completed, the
seaming rollers
are retracted from the surface of the pipe, the pipe is rotated or indexed
until the next
row of slots is aligned with the rollers, and the treatment process is
repeated.
Under the present method, after the seaming rollers have engaged the pipe's
exterior
surface to reduce the width of slots 4, the width of the treated slots,
together with the
relative position of individual slots on the surface of the pipe, is
determined through the
use of a slot measurement device 20. The slot measurement device may be
mounted
directly upon seaming head frame assembly 16 or may be positioned on a
separate and
dedicated frame assembly. Depending upon the required level of production,
there may
1 ~ be utilized a single slot measurement device or a plurality of such
devices spaced out
along the length of the machine. The slot measurement device or devices may be
operated to measure the width and relative positions of one or more slots in a
continuous
manner as the seaming rollers are engaged against the exterior surface of the
pipe, or
they may be operated to measure the slots once the initial treatment processes
has been
completed for either one row of slots or for the entire pipe.
CA 02481696 2004-09-16
In the version of the preferred embodiment of the invention that is shown in
Figure 6,
slot measurement devices 20 are mounted directly upon each individual seaming
head
to permit a continuous and substantially simultaneous measurement of the slots
as they
are treated (preferably immediately after treatment). In an alternate
embodiment where
a complete row of slots is to be measured after the row has been treated, once
all of the
slots in one row have been seamed the pipe carriage assembly returns the pipe
to its
starting position, after which it is moved longitudinally through the seaming
machine
to allow for the measurement of the slots in the row in question. In the
further
embodiment where the entire surface of the pipe is treated before any slots
are measured,
following the treatment of all slots the pipe is re-positioned and the slots
of individual
rows are measured, after which the pipe is indexed to allow for adjacent rows
of slots
to be measured.
In the attached drawings each seaming head 8 is fitted with its own dedicated
slot
measurement device 20 mounted upon seaming head frame assembly 16. Here the
slot
measurement device is positioned adjacent to seaming roller 10 and is
configured so as
to determine the width and relative location of an individual slot immediately
following
the treatment of that slot by the seaming roller. Slot measurement device 20
may be a
camera that optically measures the width and relative position of a slot, or
may be ane
of a number of alternate types of slot measuring devices, including a laser
detection
assembly. In one form of such a Laser detection device a laser beam is focused
upon the
21
CA 02481696 2004-09-16
surface of the pipe and the percentage of the laser beam that is reflected
back and
received by a corresponding detector is recorded. The width of a slot may then
be
calculated based upon the amount of reflected light received recorded by the
detector.
In alternate embodiments of the invention magnetic imaging devices and/or
ultrasonic
equipment may be used to measure and determine the width of the slots.
Regardless of the particular farm of slot measurement device that is used its
operation
will result in the generatian of a signal corresponding to the determined
width and
relative position of a slot following treatment of the slot by seaming roller
10. That
signal is then directed to a controller, which in the preferred embodiment is
a
microprocessor 21. Controller or microprocessor 21 compares the determined
width of
a particular slot with a pre-determined value that has been programmed into
the
controller and calculates whether the slot has a width that is greater than
the pre-
determined value. Controller or microprocessor 21 preferably includes an
electronic
1 S memory 22 such that the signals corresponding to the determined width and
relative
positions of the slots may be stored for future use.
Where the controller or microprocessor determines that the width of a slot
that has been
treated remains in excess of a pre-determined value, that slot, and its
relative position
upon the surface of pipe or tubular member l, is noted by the controller so
that the slot
may be re-treated in order to bring its width into acceptable limits. In most
instances it
22
CA 02481696 2004-09-16
is expected that each row of slots will be treated; and retreated if
necessary, prior to
indexing the pipe. In this embodiment the re-treatment of the slots may
proceed in one
of two general ways. First, the slots may be individually re-treated
immediately after
they are seamed by roller 10 and before the roller is advanced to seam a
subsequent slot.
Alternately, an entire row of slots can be treated and then particular slots
in that row
subsequently re-treated before the pipe is indexed.
Preferably the re-treatment of the slots is carried out automatically by the
controller. To
accomplish this the controller is operatively connected to each of the seaming
heads, and
in particular to cylinders 19 and 25, in order to control the position of the
seaming roller
relative to the surface of the pipe. The controller will also be operatively
connected to
the means used to move the pipe and the carriage assemblies longitudinally
through the
machine so that the pipe can be re-positioned to a point where slots in need
of re-
treatment axe once again positioned below the seaming rollers. Where
necessary,
cylinders 25 may be operated to help with the alignment of seaming rollers
with
individual slots. Once the targeted slots are properly aligned with the
seaming rollers,
the controller causes cylinders l9 to force the seaming rollers into contact
with the
exterior surface of the pipe about the particular slots in question, and to
apply a
compressive force thereto. Longitudinal movement of the pipe and carriage
assemblies
at that point will then allow the seaming rollers to re-treat the targeted
slots to
selectively further reduce their widths. After the slots have been
sufficiently treated
23
CA 02481696 2004-09-16
and/or retreated the controller will cause the head stock assembly to index
the pipe and
the treatment process will be repeated for slots in adj acent rows.
In an alternate embodiment of the invention the entire surface of the pipe may
be treated
and thereafter subjected to the re-treatment process. In such an embodiment,
after the
surface of the pipe has been initially treated the controller will cause the
head stock
assembly to rotationally index the pipe in order to move a desired row of
slots into
alignment with the seaming roller. Once slots in that row in need of re-
treatment have
been sufficiently seamed, the pipe can be indexed to the next row that
contains slots
requiring re-treatment.
In a further embodiment of the invention, controller or microprocessor 21 may
have
incorporated into it programming to permit it to calculate the amount of
compressive
force (based in part upon the determined size of the slot opening) needed to
re-treat
particular slots. In such cases the controller may operate cylinders 19 so as
to apply an
appropriate amount of compressive force to complete the re-treatment step
while
reducing the likelihood of the width of the slot remaining beyond acceptable
limits after
re-treatment. In this manner the controller will also help to limit the
possibility of over
treating the slot and reducing its width to below acceptable limits.
24
..._ _... ..,. ~F~.. .,,... ._ .~. a ~.,~,~~~:,~~~~.~~..,~..~.~._.._~._._ _.__-
_...a.~~m..-.w_.. _.... _ ...._...
CA 02481696 2004-09-16
It will, of course, be appreciated from an understanding of the invention that
where a
number of individual seaming heads are utilized within seaming machine 7 there
will
be presented the ability for controller or microprocessor 21 to simultaneously
and
selectively re-treat a number of different individual slots having determined
widths
greater than a pre-determined value. The described method and apparatus
permits any
one, or any combination, of individual seaming heads to be involved in any re-
treatment
step. That is, since each seaming head is individually controllable, and as
the amount
of compressive force applied by individual seaming rollers is also
individually
controllable, there is presented the ability to completely customize the
automated re-
treatment step to bring the widths of individual slots that are outside of
specification into
acceptable limits. Through varying the amount of compressive force applied to
individual slots during the re-treatment step there is also presented the
ability to create
a finished product having a more consistent distribution of slot widths across
its exterior
surface. It should also be noted that as the re-treatment procedure advances
and the
seaming rollers treat slots identified as being outside of acceptable limits,
the slot
measurement devices will continue to operate to determine the width and
relative
positions of the re-treated slots so that they can be re-considered once again
by the
controller to determine whether they meet acceptable standards. If after re-
treatment it
is found that one or more of the slots are still outside of specification, the
re-treatment
step may be repeated once again for those particular slots that still require
a width
reduction. Controller or microprocessor 21 may be programmed to continue to
repeat
CA 02481696 2004-09-16
the re-treatment process until all, or a pre-determined percentage, of the
slots in the pipe
have widths less than or equal to the pre-determined value.
Controller or microprocessor 21 may have connected to it a digital display
screen 23 to
present a visual image corresponding to the determined width and relative
position of
the slots in pipe or tubular member 1 following the treatment of the pipe's
exterior
surface and/or the re-treatment of slots that are outside of specification.
Display screen
23 may also be used to visually present a continuous indication of the various
operational functions of the seaming machine, and may also present an operator
with the
ability to adjust operational parameters of the machine and/or manually over-
ride
particular functions where desired. In addition, since the widths and relative
positions
of individual slots in the surface of the pipe determined by slot measurement
device 20
axe stored in electronic memory 22, there is presented the ability to print
out a hard copy
of such information that may physically accompany the pipe following the
completion
of the treatment process. That hard copy may then act as a record that can be
used to
authenticate the fact that the widths of the slots in the pipe fall within
particular
specifications.
It will also be apparent from a thorough understanding of the invention that
through the
use of a slot measurement device in association with each seaming head, there
is
presented a mechanism that may be called upon to help align the seaming
rollers with
26
CA 02481696 2004-09-16
individual slots prior to treatment. When the slots within the pipe are
initially being
treated for the first time, the slot measurement devices will assist an
operator in the
initial alignment of the slots with the seaming rollers. Thereafter, any re-
treatment that
may be necessary will also be facilitated through the use of slot measurement
device 20
which may be used to re-align particular slots with individual seaming
rollers.
Through the utilization of the described method and apparatus there is
therefore
provided a system that is capable of treating and re-treating the exterior
surface of a pipe
or tubular member in order to reduce the width of slots therein to a point
where a
defined percentage of the slot widths fall within acceptable limitations. The
apparatus
and method alleviate the need to physically measure slot widths following a
seaming
process, to physically mark or identify slots having widths beyond a pre-
determined
value, to re-insert the pipe or tubular back into the seaming machine, and to
manually
retreat individual slots. The automatic measurement, determination and re-
treatment
process of the present invention significantly increases the throughput of the
seaming
operation and provides an end product with a high degree of consistency with
respect
to slot width. The slot measurement devices utilized in the invention also
permit the fast
and accurate alignment of the seaming rollers with the slots, and further
permit the
automation of the alignment process.
27
CA 02481696 2004-09-16
It is to be understood that what has been described are the preferred
embodiments of the
invention and that it may be possible to make variations to these embodiments
while
staying within the broad scope of the invention. Some of these variations have
been
discussed while others will be readily apparent to those skilled in the art.
For example,
while the seaming process described above involves the longitudinal movement
of
seaming rollers across the surface of the pipe, as indicated previously, the
seaming
rollers may also be swept in a helical path over the entire surface of the
pipe. It should
also be noted that the treatment of the exterior surface of the pipe may be
accomplished
by one or more compression tools. In addition, while the preferred manner of
applying
pressure to the pipe's outer surface is by means of a seaming roller, other
methods of
compressing the pipe (including shot bombardment) may also be used. Finally,
any one
of a wide variety of different mechanisms may be used to load and rotate the
pipe rather
than by way of the head stock assembly described herein
28
