Note: Descriptions are shown in the official language in which they were submitted.
CA 02527790 2005-11-22
1 "PIPELINE BALLAST AND METHOD OF USE"
2
3 FIELD OF THE INVENTION
4 Embodiments of the invention relate to a system and method of
installation of ballast to pipelines and more particularly to high density
ballast
6 material, arrangement of sacks and strapping systems.
7
8 BACKGROUND OF THE INVENTION
9 Pipelines are typically installed in subterranean trenches although
even in-ground trenches can extend through geographical areas having little or
11 no foundational support. Pipelines, particularly those carrying gaseous
products
12 can become buoyant in environments such as marshy areas and when under
13 water. Hydrostatic forces and resulting movement of pipelines can cause
stress
14 and fatigue which can lead to catastrophic failure.
Typically in cold areas of the world pipelines are installed in winter
16 when such unconsolidated environments are frozen. A trench is formed and
the
17 installed pipelines are weighted down with ballast of some sort including
18 concrete and clamp-on weights. Once the environment thaws, the pipeline and
19 weights become subject to hydrostatic forces and the intent is that the
pipeline is
restrained by the weights.
21 Most recently ballast is provided in a variety of sacks which avoid
22 damage to a pipeline's protective coatings. Examples of such technology
23 include Canadian Patent 2,277,523 by Jewell implementing a particular
24 strapping embodiment and Canadian Patent 2,076,006 to Connors introducing
particular forms of pipeline ballasts using ballast sacks.
CA 02527790 2005-11-22
1 Use of sacks, while safer for coated pipelines, are bulky and
2 difficult to secure to the pipeline. Conventional sacks are filled with
gravel or
3 sand. The specific gravity of gravel or sand, while substantial, still
requires a
4 great volume for providing sufficient ballast. Connors deals with the
strength and
forces on the sacks with strengthening means and reinforcement means to
6 restrict deformation and control the shape of the sack about the pipeline.
Jewell
7 has addressed some difficulties in properly securing gravel-filled sacks to
the
8 pipeline to minimize shifting.
9 Smaller pipelines can be installed into the trench with ballast
already on them. The majority of pipeline ballast is strapped to the smaller
11 pipelines before entering the ditch or trench. The weights are loaded on
the
12 pipeline and as the pipeline enters the trench on a steep angle the weights
could
13 slide down the pipeline and out of position in these conditions.
14 There is the possibility for shifting of the ballast along or off of the
pipeline due to a variety of scenarios including: inadequate securing of the
16 ballast thereto, frost heave, and possibly due to changes the buoyancy of
the
17 pipeline
18 Larger pipelines are typically placed in the trench and ballast
19 added after the fact. The underside of the installed pipeline is then
virtually
inaccessible which complicates conventional strapping means for securing of
21 ballast.
22 Further, the sheer bulk of gravel compounds the aforementioned
23 securing difficulties and adds to the time and expense for large
excavations to
24 accommodate the gravel ballast, the expense of a multiplicity of virtually
continuous side-by-side placement along a pipeline, the labor expense to
install
2
CA 02527790 2005-11-22
1 so many sacks and high shipping cost to transport so many sacks to the
2 installation point. Further, current sacks require the trench to be dug wide
and
3 deep due to the bulk of the sacks and as large sacks over hang below the
4 bottom level of the pipeline.
Thus there continues to be a need for pipeline weights or ballast
6 which resists shifting during hydrostatic, frost heave, steep incline
installation
7 conditions and other adverse conditions. The ballast is preferably readily
and
8 consistently secured to large diameter pipeline and the configuration of the
9 pipeline ballast minimizes preparation and installation expense.
11 SUMMARY OF THE INVENTION
12 A pipeline ballast of ballast is now available which can be secured
13 to the pipeline and will not move in any direction due to hydraulic, frost
heave or
14 other effects which can cause gradual movement. The weight can be used in
water or swamp conditions as well when the freeze thaw cycle is not present.
16 River and ocean crossings are also applicable. In one embodiment, high
density
17 and inert ballast is used to advantage in a pipeline ballast having at
least two
18 sacks. The high density ballast results in multiplication of the savings in
19 restraining buoyancy, enabling a lighter initial dry weight of ballast and
much
smaller volumes that compared with the sand or gravel fill. Trench width is
21 significantly reduced with savings in labor and time. Use of barite avoids
22 leaching of heavy metals associated with other high density materials. In
23 another embodiment, a pipeline ballast is provided using a top ballast sack
and
24 having two side sacks to either side of the top, middle sack and hang down
on
each side of the pipeline. When cinched, the side sacks conform to the
pipeline.
3
CA 02527790 2005-11-22
1 Preferably each side sack is a pair of sacks which are flexibly hinged for
more
2 efficient loading onto the pipeline and for better conforming to the
pipeline when
3 cinched. In yet another embodiment, an improved strapping system is employed
4 to secure peripheral materials to cylindrical base structures such as
pipeline
ballast to pipelines. In one instance, a continuous, one piece cinching strap
is
6 provided which has two tightening or lifting loops and hook and loop type
7 fasteners at the loose ends for securing together once cinched. The cinching
8 strap is wrapped about the pipeline ballast and the lifting loops are
positioned
9 one on either side of pipeline, preferably positioned adjacent the bottom of
the
sack where maximum load can be taken and the majority of tension will be on
11 bottom of pipe to ensure maximum tightening. The system can be accomplished
12 without metal components which eliminates corrosions and risk of sack
13 breakdown.
14 Thus, in one broad aspect, a pipeline ballast is provided for a
longitudinally-extending pipeline comprising: a first pair of side sacks being
16 flexibly connected longitudinally therebetween and having a top and a
bottom; a
17 second pair of side sacks being flexibly connected longitudinally
therebetween
18 and having a top and a bottom; aggregate ballast material for filling the
first and
19 second pair of side sacks, the filled first and second pairs of side sacks
being
deformable; a flexible connector extending between the top of the first pair
of
21 side sacks and the top of the second pair of side sacks and adapted to
extend
22 over a top of the pipeline with first and second pairs of side sacks
adapted to
23 straddle the pipeline; and one or more circumferential cinches adapted for
24 extending about the first and second pairs of side sacks for compressing
the first
and second pairs of side sacks radially inwardly to the pipeline.
4
CA 02527790 2005-11-22
1 In another aspect, a strap for cinching ballast about a pipeline
2 comprises: a circumferential and continuous strap having first and second
lifting
3 loops; a tension portion extending between the first and second lifting
loops and
4 having a length sufficient to extend about 1.5 times a circumference of the
ballast when cinched about the pipeline; first and second loose ends connected
6 to either end of the tension strap portion and having a length sufficient to
overlap
7 when the ballast is cinched about the pipeline; and cooperating fasteners
fit to
8 the overlapping first and second loose ends to secure the tension strap
portion
9 when cinched.
The pipeline ballast and cinching strap can be applied in a method
11 for strapping pipeline ballast to a longitudinally extending pipeline
comprising:
12 providing at least two ballast sacks adapted for straddling the pipeline
and being
13 flexibly connected over a top of the pipeline; providing one or more
14 circumferential cinches for spacing longitudinally along the ballast sacks,
each
having a tension portion, first and second lifting loops spaced apart along
the
16 tension strap portion, and loose ends extending from either end of the
tension
17 strap; wrapping each tension strap portion more than a circumference about
the
18 pipeline ballast; positioning the first and second lifting loops of each
cinch at
19 about opposing sides of the pipeline; lifting the lifting loops of each
cinch to pull
them tangentially away from each other to tighten the tension strap portion
about
21 the ballast sacks, compressing the ballast sacks radially inwardly to the
pipeline;
22 and securing the loose ends of each cinch together so as to retain tension
in the
23 tension strap portion.
24 Use of an inert and high density ballast material results in a low
volume pipeline ballast for securing to a longitudinally extending pipeline
5
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1 comprising: at least two sacks manufactured of permeable material; a
flexible
2 connector between the at least two sacks and extending over a top of the
3 pipeline for hanging the at least two sacks on opposing sides of the
pipeline; an
4 inert aggregate ballast material within the sacks, the ballast material
having a
density greater than that of sand or gravel; and one or more straps for
6 compressing the sacks radially inwardly to the pipeline.
6
CA 02527790 2005-11-22
1 BRIEF DESCRIPTION OF THE DRAWINGS
2 Figure 1A is a schematic drawing illustrating installation of ballast
3 on a pipeline before insertion;
4 Figure 1 B is a schematic drawing of the installation of a typical
smaller-diameter pipeline into a trench, illustrating installation of ballast
on the
6 pipeline before insertion;
7 Figure 2A illustrates one form of prior art sack installed to a
8 pipeline;
9 Figure 2B illustrates a high-density embodiment of one form of
pipeline ballast invention installed to a smaller pipeline such as that of
Fig. 2A
11 wherein the ballast sacks are substantially level with the bottom of the
pipeline
12 and are thereby substantially supported with minimum stress to the
pipeline;
13 Figure 2C illustrates a high-density embodiment of the current
14 invention installed to a larger pipeline wherein the bottom of the ballast
sacks are
substantially level with the bottom of the pipeline and are thereby
substantially
16 supported with minimum stress to the pipeline. A prior art sack profile is
also
17 illustrated for comparison;
18 Figure 3A illustrates one embodiment of a high density sack in
19 cross-section before and after cinching to a pipeline;
Figure 3B illustrates another embodiment of the high density sack,
21 shown in cross-section before and after cinching to a pipeline, the sack
having a
22 flex point or hinge;
23 Figure 4A illustrates the relative sizes of ballast sacks, using high
24 density barite and with sand, fit to a pipeline 26" in diameter;
7
CA 02527790 2005-11-22
1 Figure 4B illustrates relative sizes of ballast sacks fit to various
2 sizes of pipelines ranging from 4 inch to 24 " in diameter, illustrating the
smaller
3 high density barite ballast compared to larger sand ballast;
4 Figure 4C illustrates relative sizes of ballast sacks fit to various
sizes of pipelines ranging from 26 inch to 42 " in diameter, illustrating the
smaller
6 barite ballast compared to larger sand ballast;
7 Figure 5 is a layout of the sack materials of an embodiment of the
8 invention;
9 Figure 6 is an exploded and partial cross section of the lifting ports
of the pipeline ballast according to Fig. 5;
11 Figure 7 is a perspective view of the pipeline ballast according to
12 Fig. 8 ready for filling with ballast;
13 Figures 8A - 8D are sequential views of the filling, closing, sealing
14 and securing of the sacks of Fig. C respectively;
Figures 9A - 9F are cross-sectional and schematic sequential
16 views of pipeline ballast being installed to pipeline. More particularly in
Figs. 9A
17 and 9B, the pipeline ballast is lowered and placed on the pipeline,
respectively.
18 In Figs. 9C and 9D, the cinching strap is arranged and pulled to cinch the
19 pipeline ballast respectively. In Figs. 9D and 9E, the strap is secured and
all
lifting chains removed respectively;
21 Figure 10 is a perspective view of an embodiment of a cinching
22 strap;
23 Figure 11 is a perspective view of the cinching strap of Fig. 10,
24 wrapped about a pipeline ballast (not shown for better illustrating the
strap);
8
CA 02527790 2005-11-22
Figures 12A - 12F are perspective sequential views of a backhoe
placing a pipeline ballast on a pipeline.
CA 02527790 2005-11-22
1 DESCRIPTION OF EMBODIMENTS OF THE INVENTION
2 As shown in Figs. 1A and 1B, pipeline ballasts 10 having ballast
3 sacks 13 may be installed on the pipeline 11 before lowering into a trench
12 in
4 the ground. Although the context of the description is with respect to pipes
and
pipelines, the terms are to be equally applicable to cylindrical member and
6 tubular conduits generally.
7 In one embodiment, high density aggregate ballast material "B" can
8 be used in the ballast sacks 13, such as barite (barium sulphate BaS04)
9 aggregate rather than the conventional use of sand or gravel "S". Barite is
inert
and does not leach toxic compounds which is important in wet conditions.
11 Aggregate has voids between the particles which contain air which later is
12 displaced by water in wet ground conditions in a trench. The higher density
13 ballast reduces ballast sack spacing and reduces the cross-sectional
profile for
14 reducing trench size. Labor and overall cost is reduced. In some
circumstances
prior art sacks, using conventional aggregate ballast, may not even meet
16 maximum spacing requirements. For example, pipeline ballasts of the current
17 high density embodiment may only require about '/2 as many weights as would
18 be required using the prior art sand or gravel filled sacks on a sack-per-
lineal unit
19 of pipeline length comparison basis.
In this embodiment, the use of higher density materials as ballast in
21 the sacks brings unexpected advantages. For instance, barite has a particle
22 density about twice that of conventional aggregate (S.G. of 4.2 - 4.4
versus 2.3-
23 2.8). Further, because the ballast material is provided in crushed form,
with
24 voidage, the bulk density is even lower. Buoyancy is a function of its
displacement of fluid and a higher density material having lesser displacement
CA 02527790 2005-11-22
1 obtains a compounding weighting effect when immersed in fluid. From
2 Archimedes' principle, when an object is partially or fully submerged, the
buoyant
3 force, or apparent loss in weight, is equal to the weight of the fluid
displaced.
4 Barite ballast is more dense and displaces less fluid when submerged,
resulting
in a compounding of the residual weighting effect on the pipeline. Further,
barite
6 has a Mohr's hardness of between 3 and 3.5 which permits some crushing of
7 sharp angular corners with reduced sack damage when cinched and may also
8 favorably eliminates any sharp pressure points at the pipeline/sack contact
which
9 can cause corrosion of pipeline over time.
11 EXAMPLE - 30 inch pipe with Barite and Sand Pipeline Ballast:
12
13 The following is to demonstrate the difference between high density Barite
and
14 Sand when used as a buoyancy restraining device.
16 Formulas used:
17
18 Bp = Vp*K*wlo
19 Bp = buoyancy of pipe Ib/ft,
K = Environmental multiplier
21 wlo = specific weight liquid outside pipe Ib/ft3
22
23 Bn = wp+(Vb*wli)
24 Bn = negative buoyancy Ib/ft
wp = pipe weight Ib/ft
26 wli = specific weight of liquid inside pipe
27
28 Wbd = (L*Wbs*wb) / (wb-(K*wlo))
29 Wbd = weight of dry ballast Ib
L = ballast spacing, wb=specific weight of ballast material Ib/ft3
31
32 Vp = (pi*D~2) / (576)
33 Vp = displaced volume of pipe ft3/ft
34 D = pipe O.D,
36 Vb = (pi*d~2) / 576
37 Vb = pipe bore volume ft3/ft
38 d = pipe LD
39
11
CA 02527790 2005-11-22
1 Wbs = Bp-Bn
2 Wbs = weight of submerged ballast Ib/ft
3
4 Ref: KWH PIPE engineering formula for ballast design for driscoplex OD
controlled pipe, 03/2002.
6
7 Assumptions:
8 ~ Determine weight required for 15 foot ballast spacing.
9 ~ 30" pipe, I.D. 29.375"
~ weight of pipe wt = 196.08 Ib/ft
11 ~ Liquid inside pipe = air +-0.08
12 ~ L = 15'
13 ~ Dry Bulk Density (wb) of Sand = 143.52 Ib/ft3
14 ~ Dry Bulk Density Barite = 262.08 Ib/ft3
~ K environmental factor = 1.04
16 ~ Muddy trench water out side of pipe = 71.76 Ib/ft3 versus 62.3 for Iblft3
for
17 water
18
19 Calculation for Barite Pipe Weight in muddy trench water ( 71.76 Ib/ft3)
21 1. Determine the volume of liquid displaced and the buoyancy per lineal
foot
22 of pipe.
23
24 Vp=(pi*D~2)/(576), Bp=Vp*K*wlo
Vp = (Pi(30)~2)/576 = 4.9087 ft3/ft
26 Bp = (4.9087 ft3lft)(1.04)(71.761b/ft3)= 366.34 Ib/ft
27
28 2. Determine the negative buoyancy.
29
Vb=(pi*d~2)/576, Bn=wp+(Vb*wli)
31 Vb = 4.9087 ft3/ft
32 Bn = (196.08 Ib/ft) + (4.9087 ft3/ft * 0.08) = 196.47 Ib/ft
33
34 3. Determine weight of submerged ballast.
36 Wbs = Bp - Bn
37 Wbs = 366.34 Ib/ft - 196.47 Iblft = 169.87 Ib/ft
38
39 4. Determine the wt of dry ballast
41 Wbd=(L*Wbs*wb)/(wb-(K*wlo))
42 Wbd=(15*169.87 *262.08)/(262.08-(1.04*71.76)= 3562.5 Ibs
43
44 The permeable Barite pipeline ballast will weigh 3562.5 Ibs. (Versus 5309
Ibs
for sand as shown below)
46
47 The total volume required for 3562.5 Ibs. V = Wbd/wb
48 Volume = 3562.5 Ibs I 262.08 Ib/ft3 = 13.59 ft3
12
CA 02527790 2005-11-22
1 Calculation for Sand Pipe Weight in muddy trench water (71.76 Ib/ft3)
2
3 1. Determine the volume of liquid displaced and the buoyancy per lineal foot
4 of pipe.
6 Vp=(pi*D~2)/(576), Bp=Vp*K*wlo
7 Vp = (Pi(30)~2)/576 = 4.9087 ft3/ft
8 Bp = (4.9087 ft3/ft)(1.04)(71.761b/ft3)= 366.34 Ib/ft
9
2. Determine the negative buoyancy.
11
12 Vb=(pi*d~2)/576, Bn=wp+(Vb*wli)
13 Vb = 4.9087 ft3/ft
14 Bn = (196.08 Ib/ft) + (4.9087 ft3/ft * 0.08) = 196.47 Ib/ft
16 3. Determine weight of submerged ballast.
17
18 Wbs = Bp - Bn
19 Wbs = 366.34 Ib/ft - 196.47 Ib/ft = 169.87 Ib/ft
21 4. Determine the wt of dry ballast
22
23 Wbd=(L*Wbs*wb)/(wb-(K*wlo))
24 Wbd=(15*169.87 *143.52)/(143.52-(1.04*71.76)= 5308 Ibs
(Versus 3562.5 Ibs for barite)
26 The permeable Sand pipeline ballast will weigh 5308 Ibs.
27
28 The total volume required V = Wbd/wb
29 Volume = 53081bs / 143.52 = 36.98ft3
13
CA 02527790 2005-11-22
1
2 The weight of Barite required would be 3563 Ibs and the weight of
3 Sand required would be 5308 Ibs. Thus the Barite weights are only 70%
4 of the sand weight (the equivalent sand sacks weigh 50% more) so as to
achieve the same effect. Even more dramatic is the volume of Barite
6 required of 13.59 ft3 compared to the volume of Sand required of 36.98 ft3.
7 The Barite weights would be only about 40% of the volume required using
8 sand (the equivalent sand sacks consume 170% more volume).
9
Effect of trench liquid density
11
12 The difference in size and weight between Sand and Barite pipeline
13 ballasts increases as the density of the trench fluid increases. The
14 calculation above assumed a muddy slurry with a density increase to
71.76 Ib/ft3 versus a water density of 62.3 Ib/ft3 .
16
17 When the trench contains a slurry (which is characteristic of most wet
18 trench environments), the weight requirements would be increased
19 substantially over that needed for water due to the higher density of the
slurry, which further increases the advantage for using barite.
21
22 In water, the permeable Barite pipeline ballast would weigh 2423 Ibs.
23 As shown above, in a common trench slurry, the barite required would be
24 3563 Ibs. which is nearly an additional 50% of extra weight. For sand
weights in water, the pipeline ballast would weigh 3325 Ibs. Again, for a
26 trench slurry, the sand pipeline ballast would weigh 5308 Ibs. which is an
27 additional weight of nearly 60%.
28
29 The comparison of volume savings would be even more dramatic.
When pipeline ballast is in water or slurry, sand sacks consumes 36.98 ft3
31 and Barite sacks consume 13.59 ft3 respectively for a ratio of 2.72. The
32 sand sacks would be 2.72 times larger than the Barite sack and would
33 weigh (5308 Ibs / 3563 Ibs = 1.49) 1.49 times or 50% heavier.
34
Further, to minimize the size of the trench required, the ideal pipeline
36 ballast sack should not be resting below the bottom of the pipeline.
37 Therefore, it follows that the entire 2.72 times the volume of sand should
38 be placed laterally in the trench resulting in a tremendous increase in the
39 volume of dirt that has to be removed from the trench to facilitate the
larger sand pipeline sacks.
41
42 In addition, the number of sacks that would be required per unit length
43 of pipeline would be reduced dramatically when using the barite filled
44 pipeline sack weight.
46 The combination of these two factors results in dramatic cost saving
47 for the pipeline project.
48
49
14
CA 02527790 2005-11-22
1 Over and above the greater weight that can be applied, a much
2 smaller sack volume results which leads to advantages including smaller
3 trenches and thus less material handling and less expense. In the case of
large
4 diameter pipelines, it is convention to prepare a trench to allow for 12
inches
space on either side of the pipe with periodic cross-ditches where the
pipeline
6 ballasts will be placed. Use of the smaller sacks of the present invention
will fit
7 in the pipeline trench and can eliminate the added labor involved with this
prior
8 art cross-ditching.
9 Further, for example in one possible scenario, using higher density
ballast B, a 50" (12+26+12) wide trench 12 could accommodate a large diameter
11 pipeline 11 of about 26" pipe. For use with conventional gravel or sand S
12 pipeline ballasts, typically a wider and deeper wide trench 12 (which could
be in
13 the order of 96"(35+26+35) wide) would need to be excavated with all the
14 associated additional cost. Of course trench sizes vary with different
pipelines
11 and would vary with different ground conditions.
16 With reference to prior art Fig. 2A and compared to embodiments
17 of the present pipeline ballasts 10 having high density ballast of Fig. 2B
and 2C,
18 one can see that sacks 13 containing lower density ballast such as sand S
are
19 larger and have a wider and deeper profile as they rest on the bottom of
the
trench 12. When the environment softens, or thaws, the pipeline 11 may still
21 have some movement as the ballasts 10 shift on the pipeline 11. Thus,
smaller
22 higher-density sacks 13 can provide greater conformity to the pipeline 11
23 resulting in easier handling during installation and less shifting of the
ballast 10 in
24 use. More preferably hinged-style sacks 13, as discussed in more below,
further
CA 02527790 2005-11-22
1 improve conformity to the shape of the pipeline 11 and facilitate ease of
loading
2 onto the pipeline
3 The smaller sacks 13 are positioned adjacent the bottom level of
4 the pipeline 11 which allows the ground to support some of the weight of the
sack 13 and not the pipeline 11. The bottom of the ballasts 10 are at the same
6 level as the bottom of the pipeline 11 which allows for the ballast 10 to
snug up
7 around the pipeline 11 and be cinched radially inwardly and tight thereto
while
8 still having the ground take some of the weight of the pipeline 11 and the
weight
9 of the sacks 13. However, when the pipeline 11 is filled with gas or
liquids, the
full weight of the pipeline sacks 13 are immediately applied around the
pipeline
11 11 due to the snug nature of the tightening device.
12 Permeable sacks 13 assist in enabling low density air to be
13 displaced by higher density liquids, such as mud, when submerged.
14 With reference to Figs. 2B and 2C, a ballast implementation of a
high-density embodiment of the current high density embodiment is shown for a
16 30 inch pipeline 11 in contrast with the required equivalent volume using a
17 conventional prior art sack profile filled with gravel or sand S.
18 With reference to Fig. 3A and 3B, optionally, the sacks 13 of Fig.
19 3A may be replaced with a pair of sacks 14 having one or more intermediate
seams forming flex-points or hinges for greater flexibility and conformance to
the
21 pipeline 11.
22 As in the earlier embodiment, pairs of ballast sacks 14 are joined
23 with a connecting web which extends over a top of the pipeline 11 to hang
the at
24 least two sacks on opposing sides of the pipeline 11. The pairs of ballast
sacks
16
CA 02527790 2005-11-22
1 14 can be suspended and lowered onto the pipeline 11 from lifting straps or
one
2 or more loops.
3 Fig. 4A illustrates one generic embodiment of high density barite
4 ballast sacks 13 applied to a 26" diameter pipeline 11. As shown, this
conventional style of sack 13 is illustrated with the high density barite fill
B at 268
6 Ib/ft3 (8,698 Ibs, for both sides combined) with an overall width of about
40
7 inches and compared with a sack filled with prior art sandlgravel S at 160
Ib/ft3
8 (12,101 Ibs, for both sides combined) with an overall width of 64 inches.
The
9 typical length of pipeline ballast sacks 13 according to one embodiment of
the
invention is 15 feet long and spaced every 30 feet center to center. Shorter
11 pipeline ballasts 10 would be spaced more frequently. As shown, the barite
12 sacks 13 required 3403 Ibs. less weight than sand/gravel sack and requires
2.72
13 times less volume than the sand/gravel sack. In fact, sand ballast S would
have
14 to be substantially continuous along the pipeline 11 to result in the
demonstrated
profile. If sand ballast S were spaced at 30 foot intervals, the profile would
be
16 about twice as large as the large profile already represented in the
drawing.
17 Figs. 4B and 4C illustrate relative sizes of ballast sacks 13 of
18 similar design (both high density barite and sand) fit to various sizes of
pipelines
19 11 ranging from 4 inch to 42" inch diameter.
Other embodiments, using the hinged-style of embodiment are
21 typically 7 feet long for ease of handling.
22 With reference to Figs. 5 - 12F, in another embodiment, an
23 improved pipeline ballast is provided in the form of an improved
arrangement of
24 sacks 13 cinched to the pipeline 11. Further, preferably a circumferential
cinch
in the form of a unique and unitary cinching strap 50 is used which simplifies
17
CA 02527790 2005-11-22
1 handling and ensures a secure grip to the pipeline 11. The cinching strap 50
is
2 arranged to extend about the circumference of the pipeline 11 and spaced
3 radially outward and about the sacks 13. When cinched, the cinching strap 50
4 draws radially inwardly and compresses the sacks 13 to the pipeline 11. The
aggregate can shift within the sack 13 to conform to the pipeline 11.
6 With reference to Fig. 5, in one embodiment, the improved sacks
7 13 comprise a permeable material such as geotextile material 30 formed into
a
8 plurality of discrete sacks 13. Each sack 13 is connected to an adjacent
sack 13
9 by flex-points or hinges 31. Two layers of textile 30 are joined, such as by
sewing together, along substantially parallel and longitudinally-extending
seams
11 32 forming sacks 13 therebetween. The longitudinal seams 32 extend
12 substantially parallel to a longitudinal axis of the pipeline 11 and form
the hinges
13 31. The seams 32 are reinforced to resist tearing.
14 As shown in Fig. 5, a flat layout of an overlying layer of a geotextile
pipeline ballast 10 is shown sewn along a plurality of parallel seams 32 to an
16 underlying layer (not shown). As a result of the partitioning by the
parallel seams
17 32, five discrete sacks 13 are shown as formed betuveen the left and right
or first
18 and second lateral and longitudinally-extending peripheries 33. Four
19 intermediate seams 32 form five sacks 13 between the left and right lateral
peripheries 33 which ultimately form opposing bottom edges in operation. The
21 middle sack 13m forms the top sack, and the four remaining sacks 13 form
first
22 and second pairs of side sacks 14, two sacks 13,13 on each side of the
pipeline
23 11. A first end 34 of the overlying and underlying layers 30o,30u is joined
to
24 close one end of the five sacks 13 and a second end 35 is open to enable
filling
of the sacks 13.
18
CA 02527790 2005-11-22
1 The middle sack 13m is bracketed by seams 32 characterized by
2 stronger reinforcing, particularly about two or more lifting strap ports 36.
Three
3 ports are shown along each bracket seam 32. Lifting straps 37 (Fig. 6) can
be
4 passed through the ports 36 to support the underside of the middle sack 13m
and thus support the entire pipeline ballast 10 for manipulation.
6 With reference to Fig. 6, the lifting strap ports 36 are formed by
7 holes formed through the geotextile 30, and the seams 32 about the holes are
8 reinforced by sandwiching material about the hole between narrow webbings 38
9 extending along the longitudinal seam 32 and which can be discontinuous at
the
hole. A further reinforcement 39, such as woven strap material, which is wider
11 than the hole, overlies the webbings 38, sandwiching the webbings 38 and
the
12 geotextiles 30o,30u therebetween. The lifting strap 37 can pass directly
through
13 the port 36. This reinforcing 38,39 provides extra strength when lifting
and
14 handling and prevents tearing along high stress points.
With reference to Fig. 7, the over and underlying layers 30o,30u
16 form pockets 40 into which ballast can be filled or placed. The two lateral
17 peripheries 33 and the first closed end 34 are shown already closed by
joining,
18 such as by folding, a continuous sheet of geotextile 30 or otherwise by
sealing
19 open edges such as by sewing.
The five chamber pipeline ballast can be supported in a frame with
21 the second open end 35 oriented upwardly for filling (not shown).
22 With reference to Fig. 8A - 8D, the sacks are filled (Fig. 8A). At
23 Fig. 8B, the second open filling end 35 is closed and sealed such as by
sewing
24 (Fig. 8C). At Fig. 8D, to strengthen the seamed filling end 35,35, ropes 41
can
19
CA 02527790 2005-11-22
1 be passed across the second end 35 and through opposing loops 42 and drawn
2 tight to minimize the stress on the second and now sealed filling end 35,35.
3 With reference to Figs. 9A and 9B, the pipeline ballast 10 is
4 suspended by one or more lifting straps 37 supporting the middle sack 13m
and
lowered over the pipeline 11. Typically, each lifting strap 37 is rated for
10,000
6 pounds. Each lifting strap 37 is knotted in the center or top. The side
sacks
7 14,14,13,13 hang from the middle sack 13m at about the width of the diameter
of
8 the pipeline 11. When lowered over the pipeline 11, the first and second
pairs
9 14 of side sacks flex about the seams 31,32 to partially conform to the
pipeline
11. The hinged design allows the side sacks 14 to be configured to initially
hang
11 slightly wider than the diameter of the pipeline 11, which aids in smooth
loading
12 of the pipeline ballast 10 and eliminating hang-ups between the side sacks
14,14
13 and a top of the pipeline 11.
14 As shown in Fig. 9C, a cinching strapping system is used to secure
the pipeline ballast 10 to the pipeline 11. The cinching strap 50 is wrapped
16 about twice about the circumference of the pipeline ballast 10.
17 With reference to Fig. 9D, the cinching strap 50 is gripped at two
18 points 51 opposing adjacent a bottom of the ballast 10. As shown in Fig.
9E,
19 when the cinching strap 50 is lifted by points 51, the cinching strap 50
tightens
about the sacks 13, compressing and conforming the aggregate ballast within
21 the sacks 13 to the pipeline 11. As shown in Fig. 9F, loose ends 52 of the
22 cinching strap 50 are secured adjacent at the top of the pipeline 11.
23 More preferably, as shown in Figs. 10 and 11, the cinching strap 50
24 can have a configuration which minimizes handling problems. The strapping
system uses a single cinching strap 50 which is simple, easy to use and
strong.
CA 02527790 2005-11-22
1 The cinching strap 50 is separate and need not be attached to the pipeline
2 ballast 10. The cinching strap 50 can also be fit with a visual indicator of
the
3 pipeline side and the ground side, such as colored stripe 53 woven into an
4 underside of the strap 50.
The cinching strap 50 has lifting points 51 comprising first and
6 second loops 55, between which extends a tension strap portion 56. The
lifting
7 loops 55 may be formed by folding the tension strap portion 56 onto itself
at two
8 points and joining the folds together such as by sewing. The first and
second
9 lifting loops 55 could also be discrete loops sewn to the tension strap
portion 56.
The length of the tension strap portion 56 spaces the lifting loops
11 55 at a position for maximum tightening. The tension strap portion 56
extends
12 more than a circumference of the pipeline ballast 10 straddling the
pipeline 11 so
13 that the loops 55 are pulled tangentially from opposing sides of the
pipeline 11.
14 Preferably, the lifting loops 55 are positioned adjacent a bottom of the
pairs of
side sacks 14 where maximum cinching load can be imparted by pulling the
16 loops 55 tangentially away from each other and so that the majority of
tension
17 can be on the bottom of the pipeline 11 to ensure maximum tightening. The
18 tension strap portion 56 would be about 1.2 to 1.5 times the circumference
of the
19 pipeline ballast 10 when in place. The lifting loops 55 are pulled upwards
and
pull the strap slack up and tight to the pipeline 11 to avoid movement of the
21 ballast 10 during angled installation. This strapping system utilizes the
pipeline
22 loading equipment to apply as much tension to the cinching strap 50 as
required
23 to secure the pipeline ballast10.
24 The cinching strap 50 further comprises the opposing first and
second trailing loose ends 52,52 connected to either end of the tension strap
21
CA 02527790 2005-11-22
1 portion 56 and having a length sufficient to overlap when the pipeline
ballast 10
2 is cinched to the pipeline 11. The first and second trailing loose ends
52,52 are
3 fit with cooperating hook and loop type of fasteners, such as VelcroT""~ fit
to the
4 overlapping first and second loose ends 52,52. The cinching strap 50 is
continuous or unitary in that tension can be maintained along the cinching
strap
6 50 between the first and second loose ends 52,52; the tension being
sufficient to
7 maintain the compression of the sacks 13 to the pipeline 11. The strap 50 is
8 continuous in that it may be constructed of a single continuous length of
strap
9 material or that it is assembled of two of more pieces, which once assembled
can accept the necessary tension.
11 The cinching strap has two opposing surfaces 57,58. At least an
12 inside surface 57 of the first loose end 52 and the opposing outside
surface 58 of
13 the other second loose end 52 are fit with the complementary hook H or
loops L
14 for mating and securing the strap 50 to itself. More advantageously, the
other
opposing surfaces of the first and second loose ends 52,52 are fit with the
hook
16 H fasteners which can be used to temporarily grip virtually anywhere on the
17 geotextiles 30 for ease of handling intermediate the cinching operation. In
other
18 words, the first loose end 52 is preferably fit with a loop L fastener on
one
19 surface 57 and a hook H fastener on the other surface 58 while the second
loose
end 52 is preferably fit with a hook H fastener on both surfaces 57,58.
21 Returning to Fig. 9C, the cinching strap 50 is placed on the ground
22 with the tension strap portion 56 under the pipeline 11. The first loose
end 52
23 extends downwardly to the first lifting loop 55 adjacent the bottom of a
pair of
24 side sacks 14 on one side of the pipeline 11 and the other second loose end
52
is wrapped twice about the circumference of the pipeline 11 so that the
tension
22
CA 02527790 2005-11-22
1 strap portion 56 is wrapped more than a circumference of the pipeline
ballast 10.
2 This wrapping arranges the second lifting loop 55 also adjacent the bottom
of the
3 other pair of side sacks 14 on the other side of the pipeline 11. As the
cinching
4 strap 50 is being manipulated about the pipeline ballast 10, the hook H
fasteners
at the first and second loose ends 52,52 can be temporarily adhered to the
sack
6 materials 30 to minimizing fumbling. With the first and second loose ends
52,52
7 substantially unrestrained, a backhoe, crane or other equipment is
temporarily
8 secured by a lifting device 60, such as by chains, to each of the first and
second
9 lifting loops 55,55. Tension is applied substantially equally to the lifting
loops
55,55, pulling them tangentially away from each other and tightening the
tension
11 strap portion 56.
12 Thereafter, the loose ends 2,52 are secured together to retain
13 tension in the tension strap portion 56. Preferably, hook H and loop L
fasteners
14 of the first and second loose ends 52,52 are merely pressed together. While
easy to engage and pull apart in tension, the hook H and loops L are virtually
16 impossible to shear apart when the only force is along the strap 50.
17 The pairs of side sacks 14 are forced to conform to the pipeline 11
18 and thereby present a narrow profile for lowering into narrow trenches 12.
Used
19 in combination with high density ballast, trench sizes can be significantly
minimized.
21 With reference to Figs. 12A - 12F, in operation, a pipeline ballast
22 10 according to the present invention is installed to a pipeline 11. As
shown in
23 Fig. 12A, a spreader bar 61, having three lift points 62, supports the
ballast 10
24 with the pairs of side sacks 14 straddling the pipeline 11. !n Fig. 12B,
the
23
CA 02527790 2005-11-22
1 pipeline ballast 10 is set down on the pipeline 11 and the spreader bar 61
2 disengaged.
3 In Fig. 12C, one cinching strap 50 is wrapped twice about the
4 pipeline ballast 11. One or more cinching straps 50,50,50 could be used
spaced
along the pipeline ballast 10. As shown, a chain lifting device 60 is
supported by
6 the spreader bar 61 and engages the two lifting loops 55. While one cinching
7 strap 50 is shown for clarity of the drawing, three cinching straps 50,50,50
could
8 be simultaneously installed and lifted by the three points 62,62,62 of the
9 spreader bar 61.
In Fig. 12D, the lifting loops 55 are pulled to secure the pipeline
11 ballast 10 to the pipeline 11 while conforming the sacks 13 to the shape of
the
12 pipeline 11. In Fig. 12E, the loose ends 52,52 are secured and in Fig. 12F,
the
13 lifting equipment and chains are removed and two cinching straps 50,50 are
14 illustrated. The pipeline 1 is ready for insertion into a trench (not
shown).
24
