Note: Descriptions are shown in the official language in which they were submitted.
9~
1 This application is a division oE copending Canadian
Patent Application Serial No. 34~,2~6 filed January 23, 1980.
This invention relates in general to reservoirs and
more particularly to a method of lining a containment reservoir
and a liner for carrying out the method. The liner comprises
a layer of pervious fabric material and a layer of liquid
imper~ious material, with the liner being operable to re-tain
received liquid in the con~ainment space.
Background of the Invention
Reservoirs formed with a flexible liner layed in or
lining an earthen containment space, or lining a tank, are well
known in the art. U.S. patents 3,872,007, 3,474,625 and 1,081,515
disclose various arrangements of formed reservoirs utilizing
a flexible liner. However, these prior art reservoirs generally
provide for the liner being a one piece affair, defining the
entire containment space or reservoir, and have not been
entirely satisfactory. Moreover, to applicant's knowledge,
no one heretoEore has provided a containmen-t reservoir utili-
zing a flexible liner material, and having a covering layer of20
pervious fabric material overlying the opening into the
reservoir, for filtering liquid passing into the reservoir,
and as is disclosed in applicant's invention.
Summary of the Invention
The present invention provides a method of lining a
containment reservoir and a liner for carrying out the method.
The liner comprising a layer of pervious Eabric material having
on at least one of 7 ts sides a layer of impervious material
such as rubber, with such liner being operable to resist or
prevent escape of liquids from -the containment space.
Accordingly, an object of the invention is to provide
a novel method of lining a containment reservoir for liquids,
such as petroleum based oils.
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1 A further objec-t of the invention is to provide a
novel method of the above type in which the containment space has
a liquid impervious liner generally following the contour
thereof in at leas-t one direction and with the liner comprising
a layer of pervious fabric material and a layer o~ impervious
material, such as rubber, with the impervious layer facing
outwardly of the space, and with the liner being operable to
resist escape of liquids from the space, through the liner.
A further object of the inventi.on is to provide a
liner for carrying out the above wherein the liner comprises
a non-woven polyester fabric material layer having a rubber
coating bonded or secured to one side of the perv.ious layer,
and forming thc impervious.layer of the liner.
A still further object of the invention is to provide
a liner comprised of a plurality of strip sections, each of
predetermined width, with the strip sections being joined at the
junctures thereof, and forming the liner for the reservoir~
Other objects and advan-tages of the invention will be
apparent from the following description taken in conjunction
with the accompanying drawings wherein:
Brief Description af the Dr _ings
FIGURE 1 is a top plan, broken, fragmentary view of
a reservoir in combination with a railroad -track section, for
containing liquids, such as petroleum based oil, that is in-
advertently spilled from vehicles on the railroad track section,
or during fueling of such vehicles, so as to prevent the
seepage of the oil into the soil areas adjacent the track section,
and to retain it in a reservoir disposed beneath the track
section, for subsequent salvage.
FIG~RE 2 is a vertical transverse sectional view of the
lined reservoir of FIGURE 1.
1 FIGUR~ 3 is an enlarged view of a section of the top
portion of the reservoir of the FIGURES 1 and 2, illustrating
details oE the structure.
FIGURE 4 is an enlarged, vertical sectional view of the
liquid impervious liner utilized in the reservoir oE FIGURES 1-3,
and is taken generally along line ~-4 of FIGURE 2, looking in
the direc-tlon of the arrows.
E'IGtJRE 5 is an enlarged vertical sectional view taken
genera~ly along the plane of line 5-5 of FIGURE 2, looking in
the direction of the arrows, and illustrating the pervious layer
of fabric ma~erial overlying -the open top of the reservoir o~
FIGURES 1-3.
FIGURE 6 is a view generally similar to that of
FIGURE 1, and illustrating another embodiment of containment
reservoir in association with a section of railroad track.
FIGURE 7 is an enlarged, transverse sectional view
of the reservoir of FIGURE 6.
Descrip-tion of Preferred Embodiments
Referring now to FIGURES 1 throuyh 5, there is
illustrated the combination of a containment reservoir 10
formed in accordance with the invention, and a railroad track
section 11. The railroad track section comprises ~paced
rails 12 and 13 which are supported in the conventional manner
on ties 14 which in this case, are shown as wood ties 14.
However, any suitable type of tie structure, including concrete
ties may be used. The railroad track sec-tion 11 is adapted
to carry conventional railroad equipment including diesel
powered locomotives. Containment reservoir 10 formed in
accordance with the invention extends beneath and laterally of
track section 11. Reservoir 1~ comprises a space or pit 16 in
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32
the ground, opening upwardly and encompassing -the railroad
track section 11 for a predetermined portion of the length
thereof. The walls of the containment space 16 in the embodiment
illustrated, are sloping downwardly and inwardly ~FIGURE 2)
so that any liquid in the reservoir drains downwardly toward a
central drain area 20 of the space, the latter area preferably
comprising generally ~ertically oriented walls 21 which merge
with the diagonal defining side wall surfaces 16a of the
space 16~
In accordance with the invention, the walls of space 16
are covered with a liner 22 so as to restrict or prevent escape
of liquid from the containment space into the surrounding
ground area. The liner comprises a layer 2~ (FI~URES 3 and 4)
of pervious fabric material, such as for instance a non-woven
polyester fabric. A preferred fabric material is known in the
trade as "Bidim" engineering fabric manufactured by Monsanto
Textile Company of St. Louis, Mo. This "Bidim" fabric is a
random entanglement of polyester filaments, and is of relatively
low fabric density, which enables li~uids to pass completely
through the "Bidim" layer. The "Bidim" fabric is manufactured
by needle punching of direct spun polyester filaments which
may be continuous filaments The fabric has nearly the same
tensile strength in all directions and therefore withstands
large local deformation, and possesses excellent puncture
resistance, while still being of a highly porous nature. The
fabric will generally retain or hold back particles larger than
about 70 microns, while permitting smaller liquid-borne fines
to pass through without clogging the fabric. Moreover, there
is negligible change in the physical properties of the "Bidim"
fabric from below zero temperatures to temperatures as high
ll32
1 as 4000F. The l'Bidim" conventionally comes in various
standard widths in roll form, such as for instance 13 ~t. 6 in.
wide, or approximately 17 ft. 4 in. wide. Fabrlc layer 24 may
be anywhere from approximately 60 to 190 mils in thickness.
The liner 22 also comprises a layer 25 of material
impervious -to li~uid, such as rubber, with the impervious layer
in the embodiment illustrated in FIGURES 1-3, facing outwardly of
the ccntainment space. The impervious layer 25 can be applied
to the layer of pervious fabric material by conventional calender~
ing processes, known in the rubber art, resulting in a liner
which while highly flexible, is impervious to the flow o~ liquid
therethrough~ The thickness y of the impervious layer 25 may
be approximately one-third the thickness x of the pervious
layer 24. ~lowever, 6-10 mils of rubber also impregnates into
the pervious layer and thus is securely fastened or bonded
thereto. The rubber is preferably resistant to oil degradation
(e.g. Nitrile Rubber). The rubber is calendered onto strips
of the fabric of predetermined width ~e.g. 60 inches~ and
length (approximately 984 feet) and then such rubber coated
fabric strips are fastened together or joined by conventional
adhesive means, and cured, and then cut, to form a predetermined
width and length of coated fabric stock ~e.g. 19 feet wide x
100 feet long~ which is subsequently packaged for tràns-
portation to and use at the site where the reservoir is to be
installed.
The liner may be laid down in strip form as afore-
mentioned, from rolls of liner stock material, and ~ith the
strips being preferably overlapped as at 26 (FIGURE 7) for
providing a lined containment reservoir of any desired size.
The overlapping preferably occurs in a downward direction as
32
1 illustrated, and preferably on oblique or vertical portions of
the containment space. The overlapped sections o~ the coa-ted
fabric are preferably secured together by suitable and known
adhesive means, which can be applied at the site, so that there
is no chance for liquid to seep between the junct~re portions
and escape from the reservoir into the surrounding ground area.
Leading from the drain portion 20 of the containment
reservoir is at least one passageway 28 (a plurality of such
passageways being illustrated in FIGURE 1) for draining the
reservoir. Such passageways communicate through the liquid
impervious liner as by means of ports or punc-ture openings 29
(FIGUR~ 2) in the liner and passageway 28 preferably slopes
downwardly toward a transversely extending larger further
passageway 30 running generally parallel (FIGURE 1) to the
reservoir and associated track section. Passageways 28 and
30 are preEerably lined as by means of tile or concrete or any
other suitable material, for preventing the liquid received
from the con-tainment reservoir from passing or seeping into
the surrounding ground areas.
~ Communicating with passageway 30 are vertical shafts
32, providing access to the passageway 30, with such shafts
being preferably covered by manhole covers 32a. It will be
seen that upon removal of the covers 32a, access is provided
to the shafts 32 opening or communicating via an opening in the
top of passageway 30, with the respective shaft 32. Liquid
that is caugh~ in the reservoir 10 will drain by gravity down
through drain section 20, down passageway 28 into passageway 30,
where it may be removed by gravity flow to a more remote
location or a storage facility (not shown). Passageways 32
provide access to drain passageways 28 and 30 for clean out
purposes.
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8Z
1 The containment space 16 is filled ~i~h a lump-like
material of rela-tive large or coarse size~ such as rai~way bed
ballast 35, comprising stones or the like conventionally
utilized in conjunction with a railroad track installation.
Such ballast bed~ has very little if any, fines; to prevent
clogging of the bed. Such highly porous layer~ 35 of ballast
will readily pass therethrough liquid cau~ht b~ the reservoir.
The space 16 is of sufficient depth to preferably provide a
minimum of 8 inches depth of ballast layers beneakh ties 14.
It will be seen that the upper end of the reservoir on
its sides is preferably defined in part by generally vertical
earthen side wall sections 36, which are covered by sections 38
of the liner material. Such upper wall sections 38 of the
liner preferably extend horizontally as at 38a for a predetermined
width, and then are retained in position as by means of the
adjacent soil, to hold the respective upper end wall liner
section 38 in position. It will be understood of course that
means other than abutting soil could be provided for anchoring
or holding the upper sections of the liner in place. The
portion of liner 22 in the containment or pit area, is
positively maintained in position hy the weight of the ballast
supported on the liner, but since the liner is of puncture
resistant material as aforementioned, such ballast does not
injure the liner.
In this embodiment of reservoir, the ties 14 are
embedded in the ballast in the conventional manner of supporting
railroad ties, and thus are held in predetermined position and
support the track members 12 and 13 thereon.
In order to filter liquid, such as fuel and/or
lubricating oils that may drip down from the diesel locomoti~es
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1 or other vehicles on track section 11, prior -to the liquid
passing into the containment space, and to prevent plugginy
of the porous ballast layer 35, the top of the reservoir is
preferably covered by a layer 40 of flexible pervious fabric
material, such as the aforementioned "Bidim" fabric, with said
upper layer 40 extending from the aforedescribed upper sections
38 of the liner 22, to the .respective rail members 12 or 13,
as well as across the space intermediate the rail members 12
and 13. As best shown in FIGURE 2, layer 40 may be tucked
in~ardly and downward].y as at 41, adiacent liner sections 38.
In order to maintain the top pervious layer of fabric
matexial in place covering the top of the reservoir, the strip
of material intermeaiate the track or rail members 12 and 13,
and on either side thereof for a predetermined distance out-
wardly therefrom, are weighted down by preferably metal grating
42~ w~ich is preEerably of articulated construction, and which
hold the sections of pervious filter layer ma-terial 40 in
position covering the -top end of the reservoir. Laterally
outwardly from the grating sections 42, the pervious layer 40
can be covered with a relatively thin layer 44 oE aggregate
material, s~lch as the aforementioned ballast material, or some
other porous layer, for weighting the pervious fabric layer 40
down a~ainst the ballast layer 35. As liquid, such as petroleum
based fuel oil drips down, say for instance, from a diesel
locomotive, it will pass through the grat.ing 42 or the par-
ticle weigh down layer 44, and then through the porous fabric
filter layer 40 down into the ballast filled reservoir, where
the oil drains down to the drain section 20, then by gravity
down through passageway 28 to further passageway 30, where
it can drain for instance by gravity to a remote storage
facility, to be reclaimed.
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32
1 While the porous layer 40 will pass liquid, such as
the aforementioned oil therethrough, it will not pass material
such as sand from the locomotive or train mechanisms passing
over the track section ll, and thus any sand or o-ther particles
larger than about 70 microns will collect on the top o~ the
filter layer 40, and will not pass into the reservoir. Thus
the oil act~lally feeding through the reservoir into drain
portion 20 thereof will not be contaminated by sand, or other
fines. Moreover, clogging of the reservoir will be materially
delayed or prevented since the liquid will have been filtered
by filter layer ~0 as well as the ballast layer 35 in the formed
reservoir. The thickness of the porous layer 40 can be of any
selected -thickness, as for instance from approximately 60 mils
up to say for in~tance l90 mils, depending on the thickness
of non-woven fabric tha-t is provided in the fabric stock
rolls for filter layer 40. However, a thickness of approximately
75 to 90 mils has been found to be satisfactory, and is
preferred. In any event, the non-woven fabric material is
extremely porous and readily passes liquid therethrough, with
the thickness being chosen depending in part on the tear andJor
burst streng-th of the material that the installa-tion may
require.
Referrin~ now to FIGURES 6 and 7, there is shown a
further embodiment of reservoir construction lO' for use with
a railroad track section. In this embodiment, the ground
containment space 16' has side wall surfaces 36' of a much
greater slope as compared to the greater portion of the side
wall surfaces of the first described reservoir structure, with
the lower drain section 20' of the reservoir being disposed
along one lateral side of the reservoir as best shown in
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1 FIGURE 7. It will be seen that "lapping" of the liner stock
occurs as aforementioned in this embodiment, on the bottom
wall surface 46 of the reservoir, and with the slope of the
bottom wall being such tha-t any possibility of leakage or
seepage of the liquid from the reservoir at the adhesively
connec-ted overlapping juncture of the liner stock sec-tions
is positively eliminated, thus insuring that li~uid will run
down toward the drain section 20' of the reservoir. This
embodiment of reservoir is substantially deeper as compared to
the first embodiment.
In other respec-ts, the reservoir embodiment of
FIGURES 6 ~nd 7 may be generally similar to that of the first
described embodiment with any liquid draining down from railroad
vehicles o~ the track section ll' passing through the grating
42 and/or ballast layer 44, through the pervious uppèr filter
~' '~ f6~V~
layer~ 40 down through the ballast layer~ 35, in the retainer
space 16' and down to the drain section 20l, where it ~ill flow
by gravity through the passageways 28 and 30 whereupon it can
be removed.
While a particular type of non-woven pervious fabric
material has been identified (and more specifically "Bidim"
fabric) as the material for the liner 22 and the filter layer
40, it will be understood that while that is the preferable
pervious liner material for the construction of the containment
reservoirs of the invention, it may not be the only material
having similar characteristics, that would be useable in
practicing the invention. The ~lexible liner 22 of the reservoir
aids in distributing the s-tress from `the trac~ section 11 over
a wider area, and improves the load bearing characteristics
of the soil area in which the reservoir is located.
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1 The method of forming the reservoir and the structure
of the reservoir itself results in an economical yet eff~ctive
reservoir, for catching and reclaiming liquids and preventing
their passage into adjacent land areas, thereby preventing in-
troduction of undesirable materials into adjacent land areas
and thence into rivers and streams which of course would result
in pollution of public waterways.
In laying the filter layer 40 on the top of the
reservoir, the width of filter stock can be laid over the tracks
(before application of the grating ~2 and weight ballast 44) and
then a railway vehicle can be brought onto the track section 11
to run over the underlying layer of filter fabric, whereupon the
wheels of the vehicle will slice through the fabric and gravity
will cause the severed fabric sections to fall in proper position
between rails 12 and 13 and laterally thereoE, after which -the
grating ~2 and ballast layer 44 can be placed on the top of
such severed sections of fabric to weigh the latter down.
Grating 42 and ballast layer 4~ additionally prevent a slippery
condition from existing at the reservoir, since they provide a
2~ relatively good footing irrespective of being exposed to the
oil caught by the reservoir.
From the foregoing discussion and accompanying
drawings it will be seen that the invention provides a novel
relatively economical containment reservoir for liquids, such
as oil, which comprises a walled containment space opening
upwardly, with the space containing a liquid impervious liner
generally following the contour thereof, with the liner com-
prising a layer of pervious fabric material ana a layer of liquid
impervious material, and with the liner being operable to pre-
vent escape of liquid through the liner from the containment
-- 11 --
1 space. The invention also provides a containment reservoir in
which means is provided coacting with the lined containment
space for facilitating removel of -the liquid -therefrom, as
well as a novel struc-tural arrangement utilizing stock liner
material in strip form for readily cons-tructing a liner for
any necessary size of reservoir, and facilitating the movement
of the materials to the location of use in construction of the
reservoir. The invention also provides a novel method of
lining an earthen containment space, and a method of collecting
liquid from along a railroad track section.
The terms and expressions which have been used are used
as terms of descrlption and not of limitation, and there is no
intention in the use of such terms and expressions of excluding
any equivalents of any of the features shown or described, or
portions thereof, and it is recognized that various modifi-
cations are possible within the scope of the invention claimed.
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