Note: Descriptions are shown in the official language in which they were submitted.
CA 02235040 1998-04-15
TITLE: SECONDARY CONTAINMENT RETROFIT BAG
FIELD OF THE INVENTION
This invention pertains to secondary liquid containment systems in
general, and more specifically, to an oil impermeable containment bag for
installation under a residential oil reservoir for containing oil leaks from
the
reservoir.
BACKGROUND OF THE INVENTION
Because of an increasing concern of our society toward ground
water contamination, and of many such cases reported annually, regulatory
authorities in several jurisdictions now require that large oil, fuel and gas
tanks exceeding 500 gallons for example must have a secondary
containment device to prevent leakage in case of a tank rupture or
perforation. A common type of secondary containment systems used with
above-grade petroleum storage tanks used on farms, construction sites or
logging operations is a concrete vault such as the one described in U.S.
Patent 5,285,914 issued to William M. Del Zotto on February 15, 1994.
These concrete vaults are constructed to resist cracking with thermal
expansion and retraction, physical damage due to handling or collision
from automobiles or the like.
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A second common method for preventing leakage from a storage
tank is to install an impermeable bladder inside the tank. This type of
installation is illustrated and described in U.S. Patent 5,195,650 issued to
Tom Leidig, on March 23, 1993. The bladder is made with a flexible oil
impermeable material and has sufficient strength for retaining the liquid
content of the tank in case of an accident with the tank or other incidence
causing the rupture of the tank.
Although regulations have been developed for large petroleum tanks,
there is little or no regulation with regards to residential heating oil
reservoirs of 200 gallons or less. These reservoirs are typically made of
steel and are known to corrode and to eventually leak. If a leaking
reservoir is installed outside a house, heating oil can leak along the
foundation wall, seep into the drain tile and be carried with the drainage
water around the entire house. If the leak persists over a long period, it can
also seep along the well pipes and contaminate the water well if there is a
water well on the property. Similarly, if the leaking reservoir is installed
inside the house, the leakage can infiltrate under the basement floor and
become practically impossible to clean. The fumes emanating from the
underground spill could render the house unlivable, and unsaleable. Even
decades after the house has been demolished, the fumes emanating from the
soil prevents the lawful sale of the property without firstly effecting an in
depth remediation of the soil.
This lack of regulation has caused problems for homeowners, banks
and insurance companies. As one will appreciate, the problem is not just
with the homeowner, who faces massive clean-up costs and a drastic
reduction in property value, but with the insurance company holding the
insurance policy on the property, and which normally absorb the losses.
Typical clean-up costs following a spill from a leaking heating oil reservoir
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have been reported as being as high as hundreds of thousands of dollars.
When the leak gets into the aquifers of a municipality for example, the
liability could reach millions of dollars.
Oil spills are not necessarily caused by the complete rupture or
perforation of a tank where a substantial portion of the reservoir is spilled
on the ground. Oftentimes, a residential oil tank is overfilled and leaks
from the threads of the fill or vent pipe or by the level gauge on the top
part
of the reservoir. Then, precipitation washes out the oil over the surface of
the reservoir and entrains the leaking oil into the ground. In other
circumstances, leaks will occur along the fitting on the outlet pipe of the
reservoir. These leaks are normally relatively small, but are nonetheless
harmful to the environment whereas thread leaks are generally not taken
seriously and may persist for weeks and months before being fixed.
Despite the increasing awareness of people concerning
environmentally hazardous leakages of heating oil and the high cost of soil
remediation processes, it is believed that there is no system available in the
prior art for installation under new and old reservoirs alike, for preventing
severe and light spills from these reservoirs. The reason for this is believed
to be primarily due to a lacking of a practical and monetary affordable
concept as disclosed herein.
SUMMARY OF THE INVENTION
In the present invention there is provided an oil impermeable bag for
enclosing a lower portion of a residential heating oil reservoir. The bag of
the present invention is easily mountable around an oil reservoir and is
particularly appropriate for preventing environmental spills of all sizes due
to a common deterioration of these reservoirs.
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In a first aspect of the present invention, the secondary containment
bag comprises an open upper end; a stiff rim around the open upper end;
and straps extending from the stiff rim above the open upper end for
circling an upper portion of the reservoir. The bag is made of a flexible
material whereby the bag is collapsible for installation on a new tank or for
retrofitting a reservoir in service.
In another aspect of the present invention, the bottom portion of the
bag is stitch-free such that its impermeability is always maintained.
Furthermore, rubber pads are installed inside the bag under the legs of the
reservoir to prevent abrasion of the bottom portion of the bag during
installation and use thereof.
In another aspect of the present invention the size of the bag is larger
that the horizontal dimensions of the reservoir such that a gap is maintained
between the bag and the reservoir. This gap is particularly advantageous
for preventing condensation on the outside surface of the reservoir, and for
allowing odours from a spill to drift away from the bag and quickly warn
a homeowner of the presence of a leak.
In a further aspect of the present invention, the secondary
containment bag has an opening through a lower end thereof for circling an
outlet tubing system of the reservoir. A flanged connection is bonded to
the bag for sealing the opening around the outlet tubing system. The flange
connection also comprises a pipe coupling inside the bag for easily
connecting the outlet tubing system to the outlet fitting of the reservoir.
The bag of the present invention is thereby mountable over new reservoirs;
it is removable from a defective reservoir and re-mountable under a
replacement reservoir.
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In yet another aspect of the present invention, the fluid impermeable
bag has a flap detachably affixed to the stiff rim thereof for covering an
upper portion of the reservoir. The secondary containment bag with a flap
thereon is thereby mountable on a residential heating oil reservoir located
outdoors, for simultaneously containing leaks from said reservoir and for
preventing precipitations, dust and blown debris from accumulating inside
the bag.
Other advantages of the secondary containment bag of the present
invention are that it is manufacturable at a reasonable price using common
tarp manufacturing equipment. The bag is deliverable to users in a
compact folded form, and is relatively easily comprehensible such that it
is mountable under a heating oil reservoir by one or two persons with
common plumbing tools and simple instructions.
BRIEF DESCRIPTION OF THE DRAWINGS
Other advantages of the present invention will be apparent from the
following description of the preferred embodiments illustrated in the
accompanying drawings, in which;
Fig. 1 is perspective view of the front and left end of the secondary
contaimnent bag of the first preferred embodiment installed under
a residential heating oil reservoir;
Fig. 2 is a front view of the secondary containment bag of the first
preferred embodiment installed under a residential heating oil
reservoir;
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Fig. 3 is a left end view of the secondary containment bag of the first
preferred embodiment installed under a residential heating oil
re servolr;
Fig. 4 is a cross-section view of the secondary containment bag of the first
preferred embodiment as seen along line 4-4 in Fig. 1.
Fig. 5 is a top view of the secondary containment bag of the first preferred
embodiment when the bag is being manufactured. The illustration
shows a preferred folding of the material of the bag;
Fig. 6 is a side view of the piping connection through the bag of the first
preferred embodiment;
Fig. 7 is perspective view of the front and left end of the secondary
containment bag of the second preferred embodiment installed on
a residential heating oil reservoir. As is illustrated, the secondary
containment bag of the second preferred embodiment has a flap for
covering the upper part of the reservoir.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
The secondary containment retrofit bag 10 of the first preferred
embodiment is illustrated in its entirety in Figures 1 to 6. The oil reservoir
12 also illustrated therein is a 200 imperial gallon heating oil reservoir
commonly used in residential heating systems. The secondary containment
retrofit bag 10 is installed as a precautionary measure, under the lower
portion of the reservoir 12 for containing potential oil leaks from this
reservoir.
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The secondary containment retrofit bag 10 of the first preferred
embodiment is made of a fabric or flexible sheet material which is oil
impermeable and fire retardant. The substance of the fabric or flexible
sheet material is that of a tarp coated or impregnated with rubber, plastic
material or the like, such that the bag is durable and capable of holding the
content of the reservoir 12 in case of a leak.
The secondary containment retrofit bag 10 has a rectangular shape
to fit the shape of the reservoir 12. The bag is made of a single sheet of
fabric or flexible material wherein the folds 14 are tuck inside the bag 12
along the longitudinal walls of the bag 10 as represented by dash lines 14'
in Figure 2. The bag 10 does not have any stitches in its lower portion
such that its impermeability is always maintained.
The secondary containment bag 10 of the first preferred embodiment
has a horizontal band 16 sewn, or bonded and sewn along the upper edge
thereof. A pair of snaps 18 and buckle 20 are sewn transversally to the
band 16, for supporting the upper edge of the bag 10 at a set height around
the reservoir 12.
The band 16 is a continuous band of belting material and is sewn
around the entire upper edge of the bag for securing the ends and side
portions of the bag 10 together and for forming a fluid impermeable
receptacle. The band 16 is preferably made of a fire-retardant stiff belting
material or a lifting-sling-type fabric having a width of about 3 inches and
a thickness of about 3/16 inch. The purpose of the band 16 is to provide
sufficient vertical stiffiiess to the upper edge of the bag 10 such that the
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upper edge of the bag remains relatively straight, even when the bag
contains a nominal amount of fluid therein. It will be appreciated that in
other embodiments, a thinner flat horizontal band (not shown) may be
reinforced by placing a flat metal strip or the like between the band and the
bag for example before sewing the band to the bag.
The transversal straps 18 are also preferably made with a belting
material or a lifting-sling-type material. The straps 18 extend from the
band 16 on the rear side of the bag and are attachable to a pair of buckles
20 mounted on the front side of the bag 10. It will also be appreciated by
the person skilled in the art and in the light of the present disclosure, that
a number of other fastening means may also be used for detachably
retaining the straps 18 to the band 16.
The width of the straps 18 may be somewhat less than the width of
the band 16 because the straps 18 are under tension stresses only. The
preferred dimensions for the straps are about 2 inches in width and about
1/8 inch thick.
The lower end of the secondary containment retrofit bag of the
preferred embodiment has a flanged connection 22 for sealing an opening
in the bag around the outlet tubing system 24 of the reservoir 12. The
details of the flange connection 22 will be explained later when making
reference to Figure 6.
Referring now to Figure 4, the 200 imperial gallon reservoir
illustrated therein has a height "H," above the ground of about S 1 inches
when the reservoir is mounted on legs 28 having a height "HZ" of about 6
inches. The reservoir 12 is preferably mounted on hard rubber pads 30
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bonded to the bottom surface of the bag 10 for absorbing the weight of the
reservoir, and for preventing the abrasion of the bag under the legs of the
reservoir.
The height "H3" of the secondary containment retrofit bag of the
preferred embodiment is about 39 inches. The perimeter of the rim portion
of the secondary containment retrofit bag 10 of the preferred embodiment
is about 8-10 inches more than the horizontal perimeter of the reservoir 12
such that a gap "G" of at least one inch is maintained between the reservoir
12 and the inside surface of the bag 10.
The gap "G" ensures that any fluid which may be accidentally
spilled on the surface of the reservoir or along the fill or vent pipes 32,
during filling of the reservoir for example, will flow into the secondary
containment bag 10. The space "G" between the reservoir and the bag,
and the open upper end of the bag are further advantageous for maintaining
an air circulation inside the bag for preventing condensation on the surface
of the reservoir. The air circulation inside the bag is further advantageous
for carrying away any odour that may emanate from a leak and for quickly
warn a homeowner of the presence of a leak before the condition reaches
a critical stage.
The volume Vl of the bag 10 having the above dimensions is
approximately 48 imperial gallons. The volume VZ inside the reservoir 12
above the rim of the bag 10 is about 46 imperial gallons. Therefore, in case
of a leak, the secondary containment retrofit bag 10 of the first preferred
embodiment is able to contain the full content of the reservoir 12.
Furthermore, the space "G" between the bag and the reservoir allows the
insertion of a hose inside the bag for draining the content of the bag 10
after a leak for example.
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The secondary containment retrofit bag 10 of the preferred
embodiment is made of a single piece of fabric or a sheet of flexible
material as explained previously and as better illustrated in Figure 5. The
folds 14 in the fabric or flexible material between the side portions 36 and
the end portions 38 are preferably inserted inside the bag 10 alongside the
side portions 36. The folds 14 are preferably bonded to the side portions
36.
After folding the fabric in this manner, the band 16 is sewn or
bonded and sewn to the upper edges of the bag for securing the folds 14 to
the side portions 36 and for securing the side portions 36 to the end potions
38 in order to obtain a sturdy and leak-proof construction. The rubber pads
30 are bonded to the bottom surface of the bag 10 at locations to match the
spacing of the legs 28 of the reservoir 12, as illustrated in Figure 5.
Referring now to Figure 6, the flanged connection 22 is illustrated
therein. The flanged connection 22 has a circular disc 40 which is bonded
to the end portion 38 of the bag 10 around an aperture in the end portion
38. The connection 22 further has a tubular member 42 bonded through the
disc 40 or making integral part of the disc 40. The tubular member 42 has
a threaded connection for receiving an outside pipe nipple 44 extending
outside the bag 10, and an inside pipe nipple 48 extending inside the bag.
The outside pipe nipple 44 is typically connected to a shut-off valve 50 and
a filter 52 on the outlet tubing system 24. The inlet pipe nipple 48 is
connected to a pipe coupling 54, which is connected to a third pipe nipple
56 threaded into the reservoir's outlet fitting 58.
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The secondary containment bag 10 of the preferred embodiment is
preferably packaged and delivered to clients in a folded form. The bag is
preferably deployed in a collapsed form and inserted under the reservoir
with the legs 28 of the reservoir resting on the pads 30. This installation
is preferably effected by tilting the reservoir lengthwise, raising one pair
of
legs at the time while inserting the bag and the rubber pads 30 under the
raised legs. It will be appreciated that the installation is preferably
effected
by two persons when the reservoir 12 is empty or nearly empty such that
it can be manipulated relatively easily.
The inlet side of the pipe coupling 54 is then connected to the outlet
pipe nipple 56 of the reservoir. The outlet side of the pipe coupling 54 is
preferably assembled to the inside pipe nipple 48, and to the flanged
connection 22 prior to installing the bag under the reservoir. The pipe
coupling 54 is then assembled for joining the outlet pipe nipple 56 to the
outlet tubing system 24. This connection is preferably effected with the
reservoir tilted slightly along its length for raising the outlet fitting 58
above the fluid level inside the reservoir. The rim 64 of the secondary
containment bag 10 of the first preferred embodiment is then pulled
upwardly and the straps are fastened over the reservoir 12 as shown in the
Figures 1 to 4 for securing the bag to the reservoir.
It will further be appreciated by the person skilled in the art that
when the reservoir 12 is installed below the elevation of the furnace's
burner, as often seen in mobile homes, the length of the bag may be
increased slightly for containing an outlet tubing system 24' oriented
upwardly for example. The flanged connection 22 is thereby not required
in these cases. This type of arrangement is illustrated in Figure 7.
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There is also illustrated in Figure 7, a second preferred embodiment
60 of the secondary containment bag of the present invention. The bag 60
of the second preferred embodiment of the present invention is similar to
the bag 10 of the first preferred embodiment described in the foregoing.
The bag 60 of the second preferred embodiment 60, further has strips 62
of gripping material such as Velcro .LM for example, along the longitudinal
band 64. A flap 66 is detachably mounted to the longitudinal band 64 of
the bag for covering the upper portion of the reservoir 12. The flap 66 has
strips 68 of retainable material affixed to the periphery thereof for
attachment to the strips 62 of gripping material such that the flap 66 is
detachably retainable to the longitudinal band 64.
The covering flap 66 has a hood 70 extending above the surface
thereof for covering the fill and vent pipes, and the fluid level gauge of the
reservoir. The covering flap 66 of the secondary containment bag 60 of the
second preferred embodiment is easily detached and lifted up by the
heating oil delivery person for example, for filling the reservoir or for
looking at the fluid level gauge. The covering flap 66 is convenient for
covering the reservoir and for preventing the accumulation of precipitation,
dust and leaves inside the bag 60 when the reservoir is installed outside a
house for example.
The length of the covering flap 66 is preferably between about 10
to 16 inches longer than the oil reservoir 12, with half this surplus length
extending of each end of the reservoir. Both ends of the flap are preferably
left open as illustrated in Figure 7 for maintaining an air circulation inside
the bag with the associated advantages as previously explained.
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The flexible and impermeable aspects of the material of the bags of
the first and second preferred embodiments 10,60 are particularly
convenient for cleaning the inside surfaces of the bags after a leak, even
when the bag is still installed under a reservoir, or for cleaning and reusing
a bag on a new replacement reservoir. The bags of the present invention
are easily lowered by undoing the belt and buckle connections. With the
bag in a collapsed form, it is relatively easy to reach in and to wipe and
sponge off any fluid residues from inside the bag.
While the preferred embodiments have been described for use on a
residential heating oil reservoir having a fluid capacity of 200 imperial
gallons, it will be appreciated that the bags of the present invention can be
used on different volume tanks as well as on reservoirs having
configurations other than the conventional oblong shape of the illustrated
reservoir.
Therefore, the preferred embodiments of the invention as illustrated
herein is not limited thereto, and it will be apparent to those skilled in the
art that numerous modifications form part of the present invention insofar
as they do not depart from the spirit, nature and scope of the described and
claimed invention.
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