Note: Descriptions are shown in the official language in which they were submitted.
CA 02509748 2005-06-10
STORAGE TANK FILLING DEVICE
TECHNICAL FIELD
A filling device for a storage tank and a storage tank system comprising a
storage tank and a filling device.
BACKGROUND OF THE INVENTION
A storage tank for a liquid, including a fuel such as gasoline and diesel,
typically
includes a tank inlet to facilitate filling of the storage tank with the
liquid and a tank outlet to
facilitate dispensing of the liquid from the storage tank. These
characteristics apply particularly
to an above-ground storage tank, but may also apply to a storage tank which is
below ground or
which is submerged in some other medium.
During filling of the storage tank, a tanker truck or some other source of a
liquid
is connected with the tank inlet in some manner so that the liquid can be
transferred from the
source of the liquid to the storage tank via the tank inlet. During dispensing
of the liquid from
the storage tank, the tank outlet is opened so that the liquid is dispensed
via the tank outlet.
During filling of the storage tank, gas such as air, water vapour and/or
volatile
hydrocarbons within the storage tank must be expelled from the storage tank in
order to avoid a
buildup of excessive pressure within the storage tank. During dispensing of
the liquid from the
storage tank, gas must be permitted to be introduced into the storage tank to
avoid the creation
of a vacuum within the storage tank. The gas is typically expelled from the
storage tank and
introduced into the storage tank either through the tank inlet or through a
separate gas outlet.
If the storage tank is provided with a tank inlet and a separate gas outlet,
the
source of the liquid may be connected with the tank inlet in a manner so that
the tank inlet is
completely sealed during filling of the storage tank and functions only as a
liquid inlet, since the
necessary expulsion of gas from the storage tank will occur through the gas
outlet. For
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example, the source of the liquid may include a conduit with a coupler or
fitting which engages
with a complementary coupler or fitting on the tank inlet to provide a sealed
connection
between the tank inlet and the source of the liquid. During dispensing of the
liquid from this
type of storage tank, the necessary introduction of gas into the storage tank
can occur through
the gas outlet.
If the storage tank is not provided with a separate gas outlet, the necessary
expulsion of gas during filling of the storage tank must occur through the
tank inlet so that the
tank inlet functions as both a liquid inlet and a gas outlet. For example, the
source of the liquid
may include a hose which is smaller than the tank inlet and which is inserted
and held in the
tank inlet during filling of the storage tank, thus effectively providing a
gas outlet during filling
of the storage tank in that portion of the tank inlet which surrounds the
hose. During dispensing
of the liquid from this type of storage tank, the tank inlet is left open so
that the necessary
introduction of gas into the storage tank can occur through the tank inlet.
Due to the sealed connection that can be provided between the source of the
liquid and the tank inlet because the tank inlet functions only as a liquid
inlet, a storage tank
which includes a gas outlet which is separate from the tank inlet is
potentially safer and
relatively more spillproof during filling than a storage tank which does not
include a separate
gas outlet and which therefore requires the tank inlet to function as both a
liquid inlet and a gas
outlet.
In addition, a storage tank which includes a tank inlet, a separate gas
outlet, and
a sealed connection between the source of liquid and the tank inlet may easily
be configured
through the use of appropriate piping and valuing so that the sealed
connection is at any
convenient position relative to the storage tank. For example, the tank inlet
may be located
anywhere on the storage tank and the sealed connection may or may not be
located at the
location of the tank inlet, while the gas outlet may be located at an upper
end of the storage tank
in order to allow for gas both to exit the storage tank during filling of the
storage tank and to
enter the storage tank during dispensing of liquid from the storage tank.
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In contrast, a storage tank which does not include a gas outlet separate from
the
tank inlet must typically be configured so that the tank inlet is located at
or near an upper end of
the storage tank in order to avoid leaking of liquid through the tank inlet
either during filling of
the storage tank with the liquid or during dispensing of the liquid from the
storage tank.
Regardless of whether the storage tank includes a separate gas outlet or
whether
the tank inlet functions as both the liquid inlet and the gas outlet, the
potential exists for spilling
of the liquid through the gas outlet in the event that the storage tank is
overfilled. It would
therefore be advantageous if the separate gas outlet or the tank inlet which
functions as a gas
outlet, as the case may be, could communicate with a secondary containment
facility so that
liquid overflowing the storage tank is not permitted to spill.
There is therefore a need for a filling device for a storage tank and for a
storage
tank system which enable a tank inlet to function as both a liquid inlet and a
gas outlet, while
providing segregated paths for the liquid and the gas through the tank inlet.
There is also a
need for a filling device for a storage tank and for a storage tank system
which enable a tank
inlet to function as both a liquid inlet and a gas outlet while facilitating a
sealed connection
during filling of the storage tank between the source of the liquid and the
tank inlet. There is
also a need for a filling device for a storage tank and for a storage tank
system which facilitate
the filling of the storage tank from a convenient position relative to the
storage tank. There is
also a need for a filling device for a storage tank and for a storage tank
system which provide
for secondary containment of liquids which overflow from the storage tank.
SUMMARY OF THE INVENTION
The present invention relates to a filling device for a storage tank
comprising a
tank inlet and to a storage tank system comprising a storage tank and a
filling device.
The filling device is comprised of a manifold which connects with the tank
inlet
and enables the tank inlet of the storage tank to function as both a liquid
inlet and a gas outlet
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during filling of the storage tank. More specifically, the manifold segregates
the tank inlet into
separate isolated paths to provide the liquid inlet and the gas outlet.
In one aspect, the invention is a filling device for a storage tank, the
storage tank
S comprising a tank inlet and defining an interior, the filling device
comprising a manifold
adapted to connect with the tank inlet, the manifold comprising an outer
conduit
communicating with the interior of the storage tank, an inner conduit
communicating with the
interior of the storage tank and extending within the outer conduit, a gas
outlet communicating
with one of the outer conduit and the inner conduit, and a liquid inlet
communicating with the
other of the outer conduit and the inner conduit, wherein the storage tank may
be filled with a
liquid through the liquid inlet while simultaneously permitting venting of the
storage tank
through the gas outlet.
In a second aspect, the invention is a storage tank system which is comprised
of
both the storage tank and the filling device.
The storage tank is typically comprised of an upper end. The tank inlet of the
storage tank may be located substantially at the upper end of the storage tank
so that the tank
inlet is above the normal height of the liquid in the storage tank when the
storage tank is
considered to be full, in which case the gas outlet communicates with the
outer conduit, the
outer conduit communicates with the interior of the storage tank substantially
at the upper end
of the storage tank, and the liquid inlet communicates with the inner conduit.
This
configuration will enable a gas contained within the storage tank to access
the outer conduit and
thus the gas outlet while enabling the storage tank simultaneously to be
filled with the liquid
through the liquid inlet.
Alternatively, the tank inlet may be located at some other position on the
storage
tank which is below the normal height of the liquid in the storage tank when
the storage tank is
considered to be full, in which case the gas outlet communicates with the
inner conduit, the
inner conduit communicates with the interior of the storage tank substantially
at the upper end
of the storage tank, and the liquid inlet communicates with the outer conduit.
This
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configuration will enable a gas contained within the storage tank to access
the inner conduit and
thus the gas outlet while enabling the storage tank simultaneously to be
filled with the liquid
through the liquid inlet.
In preferred embodiments, the tank inlet is located substantially at the upper
end
of the storage tank so that the tank inlet is above the normal height of the
liquid in the storage
tank when the storage tank is considered to be full, with the result that the
gas outlet
communicates with the outer conduit, the outer conduit communicates with the
interior of the
storage tank substantially at the upper end of the storage tank, and the
liquid inlet
communicates with the inner conduit.
The manifold may be adapted to connect with the tank inlet in any manner.
Preferably the manifold is comprised of a connection surface for connecting
the manifold with
the tank inlet. The connection surface may be any surface which will engage
with the tank inlet
to connect the manifold with the tank inlet. The connection surface may for
example be
comprised of a flange or other surface which may be welded to the tank inlet.
Preferably,
however, the connection surface is compatible with and complementary to an
existing surface
associated with the tank inlet. For example, the connection surface may be
comprised of
threads are compatible with threads associated with the tank inlet.
The manifold may be further comprised of an upper end and a lower end,
wherein the lower end of the manifold is the end which is intended to be in
the closest
proximity to the storage vessel. The connection surface is preferably located
between the upper
end and the lower end of the manifold so that a portion of the manifold
projects within the
interior of the storage tank.
The inner conduit extends within the outer conduit such that the inner conduit
is
contained within the transverse cross-sectional area defined by the outer
conduit. Preferably the
inner conduit and the outer conduit are substantially concentric so that an
annular space is
provided between the inner conduit and the outer conduit. The inner conduit
and the outer
conduit preferably have different lengths.
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In preferred embodiments the inner conduit extends to the lower end of the
manifold so that the inner conduit projects within the interior of the storage
tank. This
configuration enables the liquid to be delivered into the storage tank below
the upper end of the
storage tank, thus minimizing splashing and turbulence within the storage tank
during a filling
operation.
In preferred embodiments the inner conduit extends to the upper end of the
manifold so that the liquid inlet is located at the upper end of the manifold.
The manifold may be further comprised of a sealing device for sealing the
outer
conduit within the manifold. Preferably the outer conduit extends from the
connection surface
to the sealing device and preferably the gas outlet is located between the
connection surface and
the sealing device so that the gas outlet is located in a sidewall of the
manifold. The outer
conduit may also extend from the connection surface toward the lower end of
the manifold, but
preferably not to the extent that the outer conduit projects below the normal
height of the liquid
in the storage tank when the storage tank is considered to be full.
The filling device may be further comprised of a filling conduit which is
connected with the liquid inlet, wherein the filling conduit comprises a
filling inlet. The filling
conduit may be comprised of any shape or length and may be constructed of any
suitable
material or combination of materials. The filling conduit may be connected
with the liquid inlet
in any manner or may be formed integrally with the manifold. Preferably the
filling conduit is
constructed entirely or substantially of metal and is connected with the
liquid inlet by welding
or with a threaded connection. The filling inlet may be provided with a
removable cap to
prevent debris from entering the filling conduit when the filling device is
not in use.
A source of the liquid may be interfaced with the filling inlet during a
filling
operation in order to fill the storage tank through the filling conduit and
the liquid inlet. The
filling inlet may therefore be comprised of an orifice which can accommodate a
hose or other
device associated with the source of the liquid during a filling operation.
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Preferably the filling inlet provides a mechanical connection between the
filling
conduit and the source of the fluid during a filling operation. As a result,
the filling inlet is
preferably further comprised of a filling conduit coupling mechanism which is
adapted to
engage with a complementary coupling mechanism associated with the source of
the liquid in
order to connect the filling conduit with the source of the liquid. More
preferably the filling
conduit coupling mechanism is adapted to engage with the complementary
coupling mechanism
in order to sealingly connect the filling conduit with the source of the
liquid. In other words,
preferably a sealed connection is provided between the filling conduit and the
source of the
liquid so that leakage and spilling can be minimized during a filling
operation.
In preferred embodiments the filling conduit coupling mechanism is comprised
of a coupling mechanism which is compatible with a hose fitting of the type
which is typically
found on refueling trucks. More particularly, in preferred embodiments the
filling conduit
1 S coupling mechanism is comprised of a cam lock style hose fitting.
The filling conduit is preferably configured so that when the filling device
is
connected with the tank inlet, the filling inlet is positioned at a lower
elevation than the tank
inlet. Preferably the storage tank is an above-ground storage tank and
preferably the filling
conduit is configured so that when the filling device is connected with the
tank inlet, the filling
inlet may be accessed while standing on a ground surface adjacent to the
storage tank. In other
words, the filling conduit is preferably configured so that a filling
operation can be conducted
from ground level, regardless of the location of the tank inlet on the storage
tank.
The filling device may be further comprised of a venting conduit which is
connected with the gas outlet. The venting conduit may be comprised of any
shape or length
and may be constructed of any suitable material or combination of materials.
The venting
conduit may be connected with the gas outlet in any manner and may be formed
integrally with
the manifold. Preferably the venting conduit at least partly of metal and is
connected with the
gas outlet by welding or with a threaded connection.
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Preferably the venting conduit is configured so that when the filling device
is
connected with the tank inlet, the venting conduit communicates with a
secondary containment
vessel so that liquid which overflows the storage tank through the gas outlet
may be contained
without spilling. As a result, the venting conduit may be constructed partly
of a suitable
S flexible hose material so that the venting conduit can be manipulated to
communicate with the
secondary containment vessel. Where a secondary containment vessel is not
otherwise present,
the filling device is preferably further comprised of the secondary
containment vessel.
The filling device may be further comprised of a liquid level gauge for
providing
an indication of the level of the liquid in the storage tank. Preferably the
liquid level gauge
provides an indication of the level of the liquid in the storage tank as the
level approaches the
normal height of the liquid in the storage tank when the storage tank is
considered to be full.
The liquid level gauge may be comprised of any suitable structure, device or
apparatus.
Preferably the liquid level gauge is comprised of a float which is adapted to
extend within the
storage tank and a reciprocable indicator arm connected with the float.
Preferably the indicator
arm extends through the outer conduit and projects from the manifold so that
the indicator arm
is visible during a filling operation.
BRIEF DESCRIPTION OF DRAWINGS
Embodiments of the invention will now be described with reference to the
accompanying drawings, in which:
Figure 1 is a schematic drawing of a preferred embodiment of a storage tank
system according to the invention, including a storage tank and a filling
device.
Figure 2 is a longitudinal section view of a preferred embodiment of a
manifold
according to the invention.
Figure 3 is a longitudinal section view of an alternate preferred embodiment
of a
manifold according to the invention, including a liquid level gauge.
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DETAILED DESCRIPTION
The present invention relates to a filling device for a storage tank and to a
storage tank system comprising a storage tank and a filling device.
Referring to Figure 1, the storage tank system (20) includes a storage tank
(22)
and a filling device (24).
The storage tank (22) is preferably an above-ground storage tank which is used
for storing a liquid (not shown). The liquid is preferably a fuel such as
gasoline or diesel, but
the liquid may be comprised of any other liquid or combination of liquids,
including water,
pesticides, herbicides, cleaning agents, lubricating oils etc. As a result,
the storage tank
preferably includes a stand (25).
The storage tank (22) has an upper end (26) and a lower end (28). A tank
outlet
(30) for dispensing the liquid from the storage tank (22) is located near the
lower end (28) of
the storage tank (22). The tank outlet (30) may be opened and closed by
turning a knob or
handle (not shown) which is associated with the tank outlet (30). The tank
outlet (30) may be
connected with a hose or other flexible conduit (not shown) to facilitate
dispensing of the liquid
to a receptacle such as a gas tank on a vehicle, gas can etc. The tank outlet
(30) is typically
closed except during dispensing of the liquid.
The storage tank (22) further includes a tank inlet (32) which is located
substantially at the upper end (26) of the storage tank (22). In the preferred
embodiment
depicted in Figure 1, the storage tank (22) is not provided with a separate
gas outlet. As a
result, the tank inlet (30) must function as both a liquid inlet and a gas
outlet. The storage tank
(22) could, however, include a separate gas outlet, in which case some of the
features of the
filling device (24) would be of less importance.
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The storage tank (22) defines an interior (34). Both the tank outlet (30) and
the
tank inlet (32) communicate with the interior (34) of the storage tank (22).
Conventionally, the storage tank (22) is filled by opening the tank inlet (32)
and
inserting a filling hose (not shown) from a refueling truck (not shown) or
other source of the
liquid into the tank inlet (32). The filling hose does not completely block or
seal the tank inlet
(32), with the result that gas such as air, water vapour and/or volatile
hydrocarbons contained
within the storage tank (22) may be expelled or vented from the storage tank
(22) through the
tank inlet (32) during a filling operation. The storage tank (22) is therefore
filled as the liquid is
passed through the tank inlet (32) and into the interior (34) of the storage
tank (22).
There are several disadvantages associated with the conventional filling
operation. First, the person filling the storage tank (22) must be positioned
above ground near
the tank inlet (32) in order to monitor the filling operation. Second, the
filling operation must
1 S be monitored constantly to avoid spilling due to the filling hose becoming
dislodged from the
tank inlet (32). Third, even if due care is taken in monitoring the filling
operation, the lack of a
sealed connection between the filling hose and the tank inlet (32) results in
a potential for
overfilling of the storage tank (22) or spilling of the liquid, with
potentially catastrophic results.
The filling device (24) is thus connected with the tank inlet (32) to increase
the
safety of the filling operation.
The filling device (24) is comprised of a manifold (36). The manifold (36) is
adapted to connect with the tank inlet (32).
Refernng to Figure 2, the manifold (36) is comprised of an outer conduit (38)
and an inner conduit (40). The inner conduit (40) extends within the outer
conduit (38). In
other words, the inner conduit (40) is contained within the transverse cross-
sectional area
defined by the outer conduit (38). This configuration serves to facilitate a
maximum cross-
sectional area of both the outer conduit (38) and the inner conduit (40) while
permitting the
manifold (36) to have a transverse dimension or diameter which is similar to
the size of the tank
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inlet (32). This configuration also renders the preferred embodiment of the
manifold (36)
relatively easy to construct, since the outer conduit (38) and the inner
conduit (40) may be
formed from separate pipes or conduits having different transverse dimensions
or diameters.
The manifold (36) may be further comprised of a housing (not shown), but in
preferred embodiments the outer conduit (38) fiznctions as a housing for the
manifold (36). The
outer conduit (38), the inner conduit (40), the gas outlet (42) and the liquid
inlet (44) may be
constructed of any suitable material, but in preferred embodiments are
constructed of metal.
In the preferred embodiment, the outer conduit (38) and the inner conduit (40)
are substantially concentric so that an annular space is formed between the
inner surface of the
outer conduit (38) and the outer surface of the inner conduit (40). Although
this configuration
provides a relatively efficient design which is relatively easy to construct,
the inner conduit (40)
may be positioned anywhere within the transverse cross-section of the outer
conduit (38). The
inner conduit (40) may even be positioned within the outer conduit (38) such
that the outer
conduit (38) and the inner conduit (40) are formed integrally and share a
common length of
sidewall.
The manifold (36) is further comprised of a gas outlet (42) and a liquid inlet
(44).
In the preferred embodiment, the tank inlet (32) is located substantially at
the upper end (26) of
the storage tank (22). As a result, as depicted in Figures 1-3, the gas outlet
(42) communicates
with the outer conduit (38) and the liquid inlet (44) communicates with the
inner conduit (40).
Both of the outer conduit (38) and the inner conduit (40) communicate with the
interior (34) of the storage tank (22). The outer conduit (38) and the inner
conduit (40) may
possibly have equal lengths, but preferably the outer conduit (38) and the
inner conduit (40)
have different lengths.
The outer conduit (38) communicates with the interior (34) of the storage tank
(22) such that gas contained within the storage tank (22) can access the outer
conduit (38) and
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thus the gas outlet (42) in order to permit venting of the storage tank (22).
Since the gas is
likely to have a lower density than the liquid which is introduced into the
storage tank (22), the
outer conduit (38) preferably does not project within the storage tank (22)
below the normal
liquid level in the storage tank (22) when the storage tank is considered to
be full.
It is not essential that the inner conduit (40) project within the interior
(34) of the
storage tank (22). Preferably, however, the inner conduit (40) projects within
the interior (34)
of the storage tank (22) such that the liquid will be introduced into the
storage tank (22) below
the interface between the liquid and the gas contained in the storage tank
(22). Most preferably,
the inner conduit (40) projects within the interior (34) of the storage tank
(22) to a location near
to the lower end (28) of the storage tank (22).
In embodiments where the tank inlet (32) is located other than substantially
at
the upper end (26) of the storage tank (22), the gas outlet (42) preferably
communicates with
the inner conduit (40) and the liquid inlet (44) preferably communicates with
the outer conduit
(38). In such embodiments, the inner conduit (40) preferably projects within
the interior (34) of
the storage tank (22) to a location substantially at the upper end (26) of the
storage tank (22) so
that the gas in the storage tank (22) can access the inner conduit (40) and
thus the gas outlet
(42). In such embodiments, the outer conduit (38) may or may not project
within the interior
(34) of the storage tank (22).
The manifold (36) is further comprised of a connection surface (46) for
connecting the manifold (36) with the tank inlet (32). The connection surface
(46) essentially
defines the location of the interface between the tank inlet (30) and the
manifold (36) by which
the outer conduit (38) and the inner conduit (40) communicate with the
interior (34) of the
storage tank (22).
In preferred embodiments, the tank inlet (32) includes threads (not shown),
with
the result that the connection surface (46) is comprised of threads (48) which
are compatible
with and complementary to the threads on the tank inlet (32).
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The manifold (36) has an upper end (50) and a lower end (52). In the preferred
embodiments, the lower end (52) of the manifold (36) is defined by the
projecting end of the
inner conduit (40) and the liquid inlet (44) is located at the upper end (50)
of the manifold (36),
with the result that the inner conduit (40) extends from the upper end (50) of
the manifold (36)
to the lower end (52) of the manifold (36).
Referring to Figures 1-3, the connection surface (46) is located between the
upper end (50) of the manifold (36) and the lower end (52) of the manifold
(36).
In preferred embodiments, the manifold (36) is further comprised of a sealing
device (54) for sealing the outer conduit (38). It is advantageous to seal the
outer conduit (38)
so that connections to the manifold (36) and the configuration of the gas
outlet (42) can both be
simplified. In the preferred embodiments, the sealing device (54) is comprised
of a bushing
which is welded in place in the annular space between the outer conduit (38)
and the inner
conduit (40). Other suitable structures or devices may, however, be used as
the sealing device
(54).
The outer conduit (38) therefore extends from the connection surface (46) to
the
sealing device (54) and the gas outlet (42) is located between the connection
surface (46) and
the sealing device (54). More particularly, the gas outlet (42) is located in
a sidewall of the
outer conduit (38), which also comprises a sidewall of the manifold (36).
The filling device (24) may be comprised only of the manifold (36). In
preferred
embodiments, the filling device (24) is further comprised of a filling conduit
(56) and a venting
conduit (58).
The filling conduit (56) is connected with the liquid inlet (44) to provide an
extension of the inner conduit (40). Similarly, the venting conduit (58) is
connected with the
gas outlet (42) to provide an extension of the outer conduit (38).
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The filling conduit (56) is comprised of a filling inlet (60) to facilitate
filling of
the storage tank (22). The filling conduit (56), including the filling inlet
(60), may consist only
of a length of pipe or conduit. In preferred embodiments, the filling inlet
(60) is comprised of a
filling conduit coupling mechanism (62) which is adapted to engage with a
complementary
coupling mechanism (not shown) which is associated with the source of the
liquid during a
filling operation. As depicted in Figure 1, the filling conduit coupling
mechanism (62) is
comprised of a coupling mechanism which is compatible with a hose fitting on a
fizel truck,
such as for example a cam lock style hose fitting. The filling conduit
coupling mechanism (62)
preferably provides a sealed connection between the source of the liquid and
the filling inlet
(60), which in turn provides a sealed connection between the source of the
liquid and the tank
inlet (32) due to the configuration of the filling conduit (56).
The filling conduit (56) may be comprised of a valve (64) for opening and
closing the filling conduit. The filling conduit (56) may also be comprised of
a removable cap
(not shown) which may be placed over the filling inlet (60) when the filling
device (24) is not in
use.
In preferred embodiments the filling conduit (56) is constructed of metal and
is
connected with the liquid inlet (44) by a welded connection between the
filling conduit (56) and
the upper end (50) of the manifold (36). The filling conduit (56) may be
comprised of a single
length of conduit, but is preferably comprised of a number of lengths of
conduit welded or
otherwise connected together to form the filling conduit (56).
The filling conduit (56) provides an extension of the inner conduit (40) so
that
the filling inlet (60) functions as the interface between the storage tank
system (20) and the
source of the liquid during a filling operation.
As a result, preferably the filling conduit (56) is configured so that the
filling
inlet (60) is located at a lower elevation than the tank inlet (32) so that a
filling operation can be
conducted from a lower elevation than the tank inlet (32). In preferred
embodiments where the
storage tank (22) is an above-ground storage tank, the filling inlet (60) is
preferably located so
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that the filling inlet (60) may be accessed while standing on a ground surface
(65) adjacent to
the storage tank (22).
The venting conduit (58) is optional, since the gas can pass directly through
the
S gas outlet (42) either from the storage tank (22) during a filling operation
or into the storage
tank (22) during dispensing of the liquid from the storage tank (22). As a
result, the venting
conduit (58) may be of any length and may be constructed from a wide range of
materials or
combination of materials.
In preferred embodiments the venting conduit (58) communicates with a
secondary containment vessel (66). The second containment vessel (66) may be
considered to
be a component of the storage vessel system (20) or a component of the filling
device (24). In
preferred embodiments the venting conduit (58) is comprised of a length of
metal conduit
which is connected with the gas outlet (42) by a welded connection and is
further comprised of
a length of a flexible hose which can be manipulated to communicate with the
secondary
containment vessel (66).
The venting conduit (58) and the secondary containment vessel (66) therefore
provide a safety feature by which liquid which overflows the storage tank (22)
through the gas
outlet during a filling operation may be contained without spilling.
The filling device (24) may be further comprised of a liquid level gauge (68)
for
providing an indication of the level of the liquid within the storage tank
(22), particularly as the
level of the liquid approaches the level where the storage tank (22) is
considered to be full.
Refernng to Figure 3, an exemplary liquid level gauge (68) is depicted, which
liquid level
gauge (68) is comprised of a float (70) which is adapted to extend within the
storage tank (22)
and a reciprocable indicator arm (72) connected with the float (70).
As depicted in Figure 3, the indicator arm (72) extends through the outer
conduit
(38) and projects from the manifold (36) in the vicinity of the gas outlet
(42). As the liquid
level in the storage tank (22) rises during a filling operation, the float
(70) and the indicator arm
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CA 02509748 2005-06-10
(72) move upward to provide an indication that the level of the liquid is
approaching the upper
end (26) of the storage tank (22).
The filling device (24) as described above may be installed on a storage tank
S (22) in order to provide a storage tank system (20). Alternatively the
storage tank (22) and the
filling device (24) may be constructed together to provide the storage tank
system (20).
In use, the storage tank system (24) is constructed either by installing the
filling
device (24) on an existing storage tank (22) or by constructing the storage
tank (22) and the
filling device (24) together. If desired, the filling conduit (56) may be
connected with the stand
(25) of the storage tank (22) with a brace (74) so that the filling conduit
(56) is supported both
by the manifold (36) and the storage tank (22).
In preparation for a filling operation, the tank outlet (30) is closed and a
filling
hose is connected with the filling inlet (60) on the filling conduit (56)
using the filling conduit
coupling mechanism (62). This connection can be performed from ground level
due to the
location of the filling inlet (60).
If a valve (64) is provided in the filling conduit (56), the valve (64) is
opened.
Liquid may then be pumped from a source of the liquid (such as a fuel truck)
into the storage
tank (22).
The liquid will pass through the filling hose, through the filling inlet (60),
through the filling conduit (56), through the liquid inlet (44), through the
inner conduit (40) and
into the interior (34) of the storage tank (22). The liquid will not pass
through the outer conduit
(38) due to the presence of the sealing device (54). As the liquid fills the
storage tank (22), the
gas contained within the storage tank (22) passes through the outer conduit
(38), through the
gas outlet (42), through the venting conduit (58) and into the atmosphere.
The level of the liquid in the storage tank (22) will be indicated by the
liquid
level gauge (68), If, however, the storage tank (22) is overfilled, excess
liquid will pass through
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the outer conduit (38), through the gas outlet (42), through the venting
conduit (58) and into the
secondary containment vessel (66).
When the filling operation is complete, liquid contained in the filling
conduit
(58) is either forced under pressure into the storage vessel (22) or is
permitted to drain out of
the filling inlet (60) and back to the source of the liquid. The valve (64)
may then be closed and
the filling hose can be disconnected from the filling inlet (60).
During dispensing of the liquid from the storage tank (22), the tank outlet
(30) is
connected with a container for the liquid either directly or through a hose or
some other
conduit. The tank outlet (30) is then opened, causing the liquid within the
storage tank (22) to
drain by gravity from the storage tank (22). As the liquid is dispensed, air
passes through the
venting conduit (58), through the gas outlet (42), through the outer conduit
(38) and into the
storage tank (22) due to the reduced pressure within the storage tank (22).
When the dispensing
of the liquid has been completed, the tank outlet (30) is closed.
The filling device (24) and the storage tank system (20) of the preferred
embodiments provide a storage tank (22) which does not include a gas outlet
which is separate
from the tank inlet (32) with a venting mechanism which permits gas both to be
expelled from
and introduced into the storage tank (22). In addition, the filling device
(24) and the storage
tank system (20) of the preferred embodiments enable the storage tank (22) to
be filled more
safely by providing a sealed connection between the source of the liquid and
the liquid inlet and
by facilitating filling of the storage tank (22) from ground level. Finally,
the filling device (24)
and the storage tank system (20) of the preferred embodiments provide
secondary containment
of overflowing liquids during a filling operation and also provide a visual
indication of the level
of the liquid in the storage tank (22) during a filling operation.
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