Note: Descriptions are shown in the official language in which they were submitted.
This invention relates to a pipeline cleaning and wrappiny
machine. More particularly, this invention relates to a machine -for
cleaning, priming, and wrapping p;pelines and is capable oF producing
product quality equal to so called yard- coating systems.
The prior art reveals a large number of machines for cleaning
and wrapping pipelines. Such machines are used to prepare a pipe for
burying underground so as to prevent, to the extent possible, any corrosion
or deterioration of the pipe after it has been buried. Since the cost
of repair after the pipe has been buried may be quite expensive, the
quality of the prepara~ion work must be high to avoid the need for
repair, to the maximum extent possible.
Many of the cleaning and wrapping machines-are oF the line-
travel type, whereby the machine travels along the pipe either by its
own propulsion system or by being towed by an adjacent prime mover. In
recent years this type of "on-line" preparation of the pipe has given
way to the so-called "yard- coating systems", wherein the pipe is coated
piece-by-piece at a coating yard, prior to assembly of the pipe sections
at the pipeline installation site. Such yard coating systems produce a
good quality coating although other disadvantages arise.
For example, a pre~coated pipe weighs more than an uncoated
pipe and thus the cost of transporting the pipe to the site is increased.
More important however, is the fact that extensive handling of the
coated pipe during transportation and later installation, may lead to
damage of the outer coat and the underlying coating so as to expose the
bare metal pipe beneath. Such damage must be repa;red, if discovered, or
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may even go undiscovered unt;l a-Fter -installation, when premature failure
due to corrosion may occur at the point where the damage was located.
Thus, the line travel type of coating system has advantages
impossible to achieve with the yard coatin~ systems.
U.S. Patent number 2,746,516 issued on 22 May 1956 to ~. D.
Cummlngs, illustrates the general principles of a line-coating system,
wherein the pipeline is lifted off the ground adjacent to the excavated
trench, is passed through the coatiny apparatus and is then deposited in
the trench.
U.S. Patent number 2,791,198 issued on 7 May 1957 to J. D.
Cummings improves upon the earlier patent by using a hot melt type of
coating with associated equipment for melting,. applying and cooling the
coating and then applying the paper tape wrap.
U.S. Patent number 3,994,766 issued on 30.November 1976 to R.
L. Dedels and U.S. Patent number 4,069,088 issued on 17 January 1978 to
S. D. Cottom, ill.ustrate more recent improvements in apparatus of the
type in question, wherein the pipeline is supported on crawler ~heels
within a frame, with the wheels being powered so as to move the apparatus
along the pipeline.. These patents also teach the use of coating application
to.the pipeline prior to wrapping and provide for brushes to clean the
pipe before the coating step.
~hile prior art wrapping machines of the line-travel type have
provided good coatings in g~neral, they have not heretof~re been able to
match the quality of the yard-coating systems. This in part is due to
the 1ack of flexibility in the wrapping of the paper or plastic tape,
the lack of adequate cleaning and scale removal and the inability to
coat the pipe evenly with dry pr;mer, prior to wrapp;n~.
The use of brushes for cleaning the pipe can produce a smooth
clean surface for the subsequent coating and wrapping operations, but
the brushes must clean the ent;re surface of the pipe evenly. A1so, a11
mater;al loosened by the brushes must be removed From ~he surface of the
pipe to provide adequate adhesion between the coating and the pipe.
The coating must be applied as evenly and uniformly as poss;ble
but often the coating material will tend to run or sag, since many prior
art coating systems simply applied the liquid coating at the top of the
pipe and allowed it to run down and round the pipe, either with or
without later efforts to smooth the coating.
The paper or plastic wrapping must be in the nature of a
helix. Differing speeds of advance of the apparatus along the pipeline
will produce different degrees of overlap of the varlous turns of the
paper or plastic tape, and may even produce gaps Detween adjacent turns
of the paper wrap.
The pr;or art machines had difficulty cleaning the pipe because
they used fixed cup brushes or block brushes which were either spring
loaded against the pipe, or were urged against the pipe by counterwe;ghts.
Such techniques have proved unable to remove millscale and rust, one of
the three major reasons for the popularity of yard-coating.
In the coating stages, previous machines simply poured the
coating onto the pipe and spread it with fabric materials, such as rugs,
dragged on the pipe surface. This type of system leaves wet primer on
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the pipe at the time the tape coating is applied, thus causin~g solvent
blisters between the pipe and the tape.
Similarly, prior art machines used a mechanism For applying
the tape which used a braking system for the tape spindle which consisted
of a drum or disc type brake attached to the core of the tape roll. This
type of system was unable to apply sufficient tension to the tape to
prevent wrinkles and sags, and thus caused poor or no adhesion bet~een
the tape and the pipe since the brake was inadequate in size, and the
equipment unable to hold a larger braking system. In addition such
brakes could not compensate for the fact that a fixed brake force on the
core of the roll would automatically vary the tension as the diameter of
the tape spool diminished as the tape unrolled from the spool.
A primary object of the present invent;on is to provide an
apparatus for cleaning, coating and wrapping pipe, which overcomes the
disadvantages of the prior art apparatus.
Another object of the present invention is to provide an
apparatus of the type described, wherein the pipe is cleaned and loosened
material is removed prior to coating.
Still another object of the invention is to provide a high
speed rotating brush for cleaning the pipe, the brush being mounted on a
structure which itself rotates round the pipe.
A further object of the invention is to provide such an apparatus
wherein the pressure of the cleaning brushes against the pipe may be
controlled by the operator and easily changed. The sub-structure rotational
2~ speed is independent of forward speed thus allowing an increase or
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decrease in the number of passes the brush makes on an area of the pipe.
This variation is necessary because the amount oF clean;ng required on
pipe varies.
Yet another object oF the invention is to provide a p;pe
cleanîng and coating apparatus where;n an airblast is used to remove
dust and fore;gn material from the surface of the p;pe prior to appl;cation
of the coating medium.
Still a further object of the invention is to provide an
apparatus wherein a uniform primer coating is appliecl to the pipe and is
dried by a pressurized air system and a final wiping to prevent blistering
of the wrapping.
Still another object of the invention is to provide an apparatus
for cleaning, coating and wrapping pipe, wherein the tape is applied
under a variable, controlled tension with a controlled variable overlap.
These and other objects and advantages of this lnvention will
become apparent upon further description of the invention.
The apparatus for cleaning, priming and wrapping pipe according
to this invention comprises a frame which encircles the pipe and includes
three longitudinally spaced bulkheads. On the first of the bulkheads is
mounted a plurality of wheels, the uppermost of which is powered so as
to move the frame along the pipe. The lower wheels are axially shiftable
on their axle, to adjust for different sizes of pipe, while the upper
wheels are also axially adjustable on their axle.
The axle for the upper wheels is mounted on a subframe which
is vertically movable so as to provide vertical adjustment for different
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pipe sizes and the lower wheels are on a pivotal -frame, to vary the
pressure against the pipe.
The upper axle is connected to a drive system so as to rotate
the upper wheels and thereby move the frame along the pipe
Mounted on the first and second bulkheads is a plurality of
rollers which support r;ng members, for rotation round the pipe passi~g
therethrough. The ring members are formed into a subframe by connecting
cross-pieces so as to form a subframe. Mounted on the subframe is a
brush mounting arrangement by which a rotating brush may be moved toward
or away from the pipe by a pneumatic cylinder. A ring gear connected to
one of the ring members is rotated, along with the subframe and brush
assembly, by a suitable motor and pinion co-operating with the ring gear.
An additional ring gear is connected to drive the brush rotation,
as well as the air co~pressor, for the pneumatic cylinder.
In the coating application section of the apparatus, a chamber
is provided with three annular manifolds separated by appropriate seals.
The first manifold directs jets of high pressure air at the pipe to
remove any dust and foreign material. ~hen the next nnanifold passes
over the pipe a flood coating of the primer material is directed at the
pipe. The seal then wipes the coating uniformly-as the pipe enters the
next section, where another blast of air is directed at the pipe to dry
the coating.
As the pipe emerges from the coating section it comes to the
wrapping station adjacent to the third bulkhead. An additional ring
member is mounted on the third bulkhead -for ro~ation and, together with
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an additional ring gear, another subframe is provided which carries the
taping head.
The ring gear of the taping section is connected to the same
drive as the crawler wheels either mechanically or eleckronically7 so
that there is a correlation between the speed of advance of the apparatus
and the speed of rotation of the tape applying mechanism around the
pipe.
The tape applying mechanism includes a spindle upon which the
spool of tape is mounted and the tape passes over an idler roller and
through a nip formed by the idler roller and a tension roller, and
thence onto the pipe.
The tension roller is "driven" by the tape passing through the
nip, and the ~ension roller is used to drive an hydraulic pump. By
controlling the output of the hydraulic pump, the resistance to movement
of the tension roller can be adjusted and thus the tension of the tape
may be controlled.
The drive for the tape applying frame passes through a variable
speed mechanism in such a manner that whîle there is a correlation
between the ro~ational speed of the tape applicator and the longitudinal
advance of the apparatusl the tape applying speed may be adjusted to
vary the degree of overlap according to speclfications or needs.
The invention will be further described in connection with the
accompanying specification and claims when taken toge~her with the
accompanying drawings in which:
FIGURE 1 is a perspective view of the apparatus of this invention;
FIGURE 2 is a top plan view of the apparatus of khis invention
with parts broken away for clarity:
FIGURE 3 is an end view as seen from the le-Ft of FIGURE 2,
FIGURE 4 ~s a plan view of the brush mounting structure and
drive arrangementi
FIGURE 5 is a longitudinal cross sectional view through the
priming and drying chamber;
FIGURE 6 is a cross sectional view of a portion of the apparatus
showing the primer coating station;
FIGURE 7 is a plan view of the taping head; and
FIGURE 8 is cross sectional view of the apparatus showing the
drive mechanism in schematic illustration.
Referring first to FIGURE 1, the apparatus according to the
-present invention is used for coating a pipeline 10. The apparatus
includes a frame portion generally designated 12, the upper frame portion
14, three longitudinally spaced bulkheads 16, 18 and 20 mounted on skids
22, or any other suitable base.
, The pipeline 10 is supported by slings 24 suspended from the
boom 26 of a suitable crane generally designated 28. The crane 28 also
includes a suitable prime mover 30 which ser~/es as a source of power for
the apparatus of the invention and is connected to the apparatus by
appropriate hydraulic lines and electric cables 32.
Turning now to FIGURES 2 and 3, it will be noted that attached
to the upper portion 14 of the frame 12 and to ~he bulkheads 16 and 18,
are four crawler assembly mounting brackets 34. The arrangement of the
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crawler assembly adjacent each of the bulkheads 16 and 18 is the same
and therefore will only be described with respect to the bulkhead 16.
Attached to the underside of the mounting brackets 34 are
spacer blocks 36 which are used to accommodate different sizes of pipe
10 by a vertical movement in accordance with the thickness of the spacer
blocks 36. Beneath the spacer blocks 36 is a bracket 38 from which
depend bearing brackets 40 which support the crawler shaft 42 in suitable
bearings 44.
Mounted on the crawler shaft 42 are two conical crawler wheels
46 and 48. The crawler shaft is threaded with opposing threads on
opposite ends thereof and the crawler wheels 46 and 48 are provided with
corresponding internal threads so that relative rotation of the shaft
and the wheels causes the wheels to move toward or away from each other
for adjustment to the pipe.
After the wheels have been adjusted to conform to the contour
of the pipe they are locked in place by any suitable means (not shown)
such as jam nuts.or the like. Thereafter, the wheels 46 and 48 will
rotate with the shaft 42. The crawler sha.ft 42 is driven by a right
angled gear box 50 which in turn is driven by a line shaft 52 which is
driven by a motor 54. The motor 54 may be either hydraul;c or electric.
The other crawler shaft assembly (not shown) is similarly driven by line
shaft 52 through a gear box 56.
On the lower portion of bulkhead 16 is an additional crawler
sha-ft assembly which is supported on a platform 58 which is pivotally
attached to bulkhead 16. The assembly includes upstanding bearing
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brackets 60 which support the crawler shaft 62 in bearings 64. The
shaft 62 is threaded with oppos;ng threads and crawler wheels 66 and 68
are provided with corresponding internal threads so that relative rotation
of the shaft 62 and the wheels 68 causes the wheels ~o rnove toward or
away from each other for adjustment to the contour of the pipe 10,
whereupon they are locked in place by su;table means (not shown)~
A pair of hydraulic or pneumatic cylinders 70 are provided and
are connected to the bulkhead 16 and platform 58. ~y actuating the
cylinders 70 to either extend or retract, the platform 58 is pivoted and
the wheels 66 and 68 are urged toward the pipe to a greater or lesser
extent to enable increasing the pressure of the driven wheels 46 and 48
against the pipe to avoid slippage, as could for example be encountered
when the apparatus is moving uphill or at an inclination. It should be
noted that this lower crawler assembly is not required on bulkhead 18.
Shaft 62 is driven by right angled gearbox 57 which in turn is driven
by either an hydraulic or el.ectric motor 59. If motor 59 is hydraulic
it is powered by hydraulic pump 61 which is driven by gearbox 50 and in
turn pumps hydraulic fluid through lines 65 to proportioning valve 63
which can increase or decrease the rotational speed of crawler wheels 66
and 68 in relation to crawler wheels 46 and 48 to eliminate slippage of
the crawler wheels 46 and 48 on pipe 10. If motor 59 is electric its
speed is proport;onately varied by control ~3 which receives information
from tachometer 61.
Also attached to bulkhead 16 are three or more shafts 72 which
mount rotatable grooved rollers 74j which in turn support a rotatable
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ring 76. Similarly attached to bulkhead 18 (FIGURES 2, 4 and 8) are
grooved rotatable rollers 78 wh;ch support ring 80. ~igidl~ connected
to both rings 76 and 80 are cross members 82 and, rigidly connected to
rin9 80 is a sprocket or ring gear 84. A motor 86 with attached sprocket
88 drives the riny gear 84 through chain 90, the motor being either an
hydraulic or electric type~ Thus, operation of the motor 86 causes the
entire sub-assembly consisting of the rinys 76 and 80 and the cross
members 82 to rotate round the pipe 10.
Rigidly secured to the bulkhead 18 is a sprocket 92 which
remains stationary.
Mounted on the cross members 82 of the subframe (FIGURES 2 and
4) is a pneumatic cylinder 94 with an associated piston rod 96 which in
turn is connected to a mounting bracket 98 at a point intermediate its
ends. One end of the bracket 98 is pivotally secured to a cross member
100 which in turn is attached to rings 76 and 80. As seen in FIGURE 4
the arm 98 carries at its other end a rotatable brush 102 mounted on
shaft 104 which is suitably journald in the arm 98. Shaft 104 also
carries a sprocket 106 keyed thereto.
Also mounted on the cross bar 100 (FIGURES 2, 4 and 8) are
integrally formed rotatable sprockets 108 and 110. An air compressor
112 having a drive sprocket 114 is also mounted on arm 98. A drive chain
116 passes around sprockets 106.9 108 and 114 while another drive chain
118 passes around sprocket 92 and 110. In this manner, as the motor 86
causes the sub~rame to rotate round the pipe 10 the drive chain 118
causes the sprockets 108 and 110 to rotate and, in turn, the air compressor
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112 and the brush 10~ are rotated, ~ecause of the reduction gearing of
this arranyement the brush 102 rotates at a high speed ~hile ;t is
orbiting the pipe 10 on the subframe. Likewise, the air pressure needed
to operate the cylinder 94 is yenerated and may be stored in tank 120.
The air tank 120 and the pneumatic cylinder 94 enable -the
increase or decrease of pressure exerted by the brush 102 against the
pipe 10 as desired.
The brush assembly may be duplicated on the rotating subframe
if desired so that one or more rotating brushes are rotating round the
pipe 10 for cleaning the surface thereof.
Referring now to FIGURES 5 and 6, after the pipe 10 has been
cleaned by the brush(es) 102, the pipe 10 next encounters the priming
section of the apparatus. The priming section is formed from a plurality
of L-shaped annular members 122, 124, 126, 128~ 130 and 134 which are
suitably attached as by welding to annular pipes or manifolds 136, 138
and 140 as shown. In addition brackets 124 and 126 are bolted together
by a bolt 142 with a flexible diaphragm 144 between. Diaphragm 144 is
provided with a central openlng 146~ slightly smaller than the outside
diameter of pipe 10.
Brackets 128 and 130 are also bolted together by a bolt 148
with another diaphragm 150 between the brackets, the diaphragm 150
having a central opening 152. In the same manner brackets 132 and 134
are bolted together by a bolt 154 and with a flexible diaphragm 156
having a central opening '158.
The manifold 136 is provided with a plurality of nozzles 160
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and is connected to a source of air under pressure. The nozzles 160
direct the air against the surface of the pipe 10 and the air carries
away any rust or foreign material which has been loosened by the brushes
102. The diaphragm 1~4 maintains a tlght ~it round ~,he pipe 10 to keep
any oF the loose foreign material out of the priming chamber.
The manifold 138 (FIGURES 5 and 6) is supplied with a suitable
primer coating material in llquid form, from a pump (not shown). The
primer is sprayed through nozzles 162 onto the pipe 10 in excess and is
allowed to flow round the entire surface of the pipe 10.
Excess primer is allowed to flow out of the primer chamber
through a drain into a reservoir 166 from which it san be recirculated.
The primer fed into the manifold 138 through an inlet f1tting 168 leaves
the manifold through outlet 170 provided with a restricting valve 172
and into the reservoir 166. Excess primer on the pipe 10 is wiped off by
the flexible diaphragm 150 as the pipe 10 passes through the opening 152
which is slightly smaller than the outside diameter of the pipe 10.
This diaphragm 150 also serves to smooth the coating of the primer on
the pipe.
After the primer is applied to the pipe the pipe passes into
the next chamber wherein manifold 140 supplies a source of drying air
which is discharged against the pipe 10 from the nozzles 174. By the
term "drying air" is meant air which is suited for drying the applied
coating of primer. Thus, in the case of a solvent based primer the air
would likely be at an ele~ated temperature in order to ef~ect the drying,
while in the case of hot melt primer it is likely that the air would be
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cooled. The airblast delivered -from nozzles 17~ is confined to a small
area by means of the diaphragm 156. An appropriate ven~ (not shown)
would be provided for exhaustiny the air.
The entire structural framework of the coating section, includiny
brackets 122134, manifolds 136140 and diaphrayms ~4, 1~0 and 156 are
supported from the main frame structure 14 by means of springs 176 which
allows the d;aphragms 144, 150 and 156 to remain concentric on the pipe
as the pipe changes direction, such as in bends or turns.
With reference now to FIGURES 1, 2 and 7, the tape wrapping
section of the apparatus of this invention will be described. The tape
178 is applied to the primer coated pipe by a taping head 180. The
taping head 180 is attached to a sprocket or ring gear 182 which is
axially spaced from but rigidly connected to a ring member 184 by means
of two radially spaced connecting bands 186. The ring gear 182, ring
member 184 and connecting bands 186 together form a closed box-shaped
annular chamber which will be discussed later.
The ring gear 182 is connected by a drive chain 188 (FIGURE 1)
to a sprocket 190 on the outputof a variable speed drive mechanism or
transmission 192. The input of the variable speed mechanism is through a
sprocket 19~ which is connected to sprocket 196 on the line shaft 52 by
means of a drive chain 198. In this manner the speed rotation of the
subframe, consisting of ring gear 182, ring member 184 and bands 186, is
in a d;rect relationship ~o the speed of the advance of the apparatus
along the pipeline 10, s;nce both the axial advan~e of the apparatus and
the rotation of this subframe are governed by the speed of the line
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shaft 52. The taping head 180 is attached to this subframe by connection
to the ring gear 182 and thus the speed of the rotation of the taping
head round the pipe is also correlated to the speed o-F axial advance.
Precise adjustment of the correlation is accomplished by controlliny the
speed of rotation oF the taping head 180 by means of the transmission
192. In this manner the helical path of the tape applied to the pipe
can be controlled, as well as the degree of overlap between successive
wraps of the tape. Another method of co-ordinating the overlap is by
variable speed electric motor 54 and variable speed transmission 192,
which are electronically co-ordinated.
A roll of tape 178 is placed on a spindle 200 and the tape is
fed partially round idler roll 202. The idler roll 202 is positioned
next to a tension roll 204 so as to form a nip between the idler roll
202 and the tension roll 204. The tension roll is connected at one end
to hydraulic pump 206, mounted within housing 208 which also supports
the spindle 200, idler roll 202 and a connecting bar 210. The hydraulic
pump is connected to a control valve 212 and a pressure gauge 214.
As the taping head 180 is rotated about the pipe 10 the tape
178 is pulled ~ff the roll mounted on spindle 2009 causing the tension
roll 204 to rotate. This in turn operates the hydraulic pump 206 to
generate hydraulic ~luid pressure. By adjustment of the control valve
to restrict or release the fluid pressure the amount of tension applied
to the tape fed to the pipe may be controlled.
The ail for the pump 206 is stored in the closed chamber
formed by the ring gear 182, ring 184 and the bands 186. As an alternative
~2~.3~
the hydraulic pressure could be fed to accumulators in the oil storage
reservoirs and used for operatlng other hydraulic equipment such as
loading mechanisms for tape rolls. This would allow hydraulic functions
to be performed while the tap;ng head is s-tationary.
In order to instal1 a new roll of tape on the sp;ndle 200, the
tape is cut close to the spindle and the free end of the tape is folded
back over rolls 202 and 20~. The old roll is then removed from the
spindle 200 and replaced with a new roll. The free end from the previous
spool of tape is then plaeed over the new roll and spliced to the new
roll. The splice will then pass through the nip between rolls 202 and
204, allowing a continuous tension to be maintained on the tape already
applied to the pipe., thereby eliminating the need for making the splice
on the pipe or loosening of the already applied tape.
The taping section may have one~ two, three or more taping
heads provided and the tension of each could be equalized for each, by
equali7ing the pressure, thereby producing a unifcrm wrapping on the
pipe.
While this invention has been described as having a preferred
desi.gn it should be understood that it is capable of further modification
and this appllcation is therefore intended to cover any variations,
uses, or adaptations of the invention following the general principles
thereof and including such departures from the present disclosure as
come within known or customary practices in the art t~ which the invention
pertains, and as may be applied to the essential features herinbefore
set forth and fall within the scope of this invention or the limits of
the appended clai~s.
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