Note: Descriptions are shown in the official language in which they were submitted.
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COUPLING ASSEMBLY WITH CHECK VALVE ACTUATOR
FIELD OF THE INVENTION
The present invention relates in general to couplings for fluid conduits such
as
pipes and hoses, and in particular to such coupling assemblies use for oil
storage tanks.
BACKGROUND OF THE INVENTION
Crude oil produced from wells drilled into subsurface formations is commonly
piped from the wells to collector tanks, each of which typically receives oil
flows from
multiple wells. When a collector tank is full or nearly so, it must be
drained, and this is
usually done by pumping the oil from the tank through a drain conduit into a
tanker truck.
For this purpose, the typical collector tank has an outlet pipe projecting
through a lower
area of the tank wall, with an end fitting adapted for connection to a drain
conduit in the
form of a drain hose from the tanker truck. To expedite the tank-draining
operation, the
outlet pipe's end fitting is usually a female camlock fitting, to receive a
male camlock
fitting on the tanker truck's hose. Camlock fittings are well known in the
art; see, for
example, U.S. Patent No. 3,860,274.
The outlet pipe is fitted with a ball valve (or other suitable type of shut-
off valve),
which is normally closed and is actuated to its open position only after the
hose from the
tanker truck has been connected to the end fitting of the outlet pipe. After
the oil has
been pumped out of the collector tank into the tanker truck, the proper
procedure is to
close the ball valve and then disconnect the hose from the outlet pipe.
Unfortunately, there have been many incidents of workers disconnecting the
tanker truck's drain hose from collector tank outlet pipe while the ball valve
is still open.
If the collector tank is completely empty or nearly so when this happens,
little harm is
done because there will be little or no oil available to spill from the outlet
pipe.
However, if the collector tank has not been completely drained when the hose
is
disconnected with the ball valve still open, a substantial amount of oil can
spill from the
outlet pipe before someone belatedly closes the ball valve.
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Incidents of this type typically necessitate costly and inconvenient
environmental
clean-up operations. An even greater concern, however, is the risk to worker
safety.
Oilfield collector tanks are commonly insulated and fitted with heaters to
keep the oil at
an elevated temperature, in order to reduce the oil's viscosity and enhance
its flowability.
There have unfortunately been numerous cases of workers receiving second-
degree or
even third-degree burns from hot oil gushing from a collector tank outlet pipe
as a result
of premature disconnection of a drain hose from the outlet pipe.
For the foregoing reasons, there is a need for an improved apparatus and
method
for draining oil from an oil storage tanks whereby the above-discussed
problems are
prevented. The present invention is directed to this need.
BRIEF SUMMARY OF THE INVENTION
In accordance with the general principles of the present invention, a check
valve
is provided in the outlet pipe of a storage tank (such as but not limited to
an oilfield
collector tank), and a hose (such as but not limited to a hose from a tanker
truck)
connectable to the outlet pipe for purposes of draining liquid from the
storage tank is
fitted with probe means adapted and configured such that the probe means will
engage
and open the check valve when the hose is connected to the outlet pipe. A
closed shut-off
valve (typically a ball valve) between the check valve and the storage tank
will prevent
flow through the outlet pipe while the hose is being connected to the outlet
pipe. The
hose-to-pipe connection is made using a camlock fitting, or another suitable
type of
fitting that does not require relative rotation between its component parts.
When the hose
is subsequently disconnected from the outlet pipe, the probe means will
necessarily
disengage from the check valve, which will thus automatically close.
Accordingly, it will
be impossible for liquid to flow out of the storage tank through the outlet
pipe upon
disconnection of the hose, even if the shut-off valve in the outlet pipe has
been
inadvertently left in the open position.
In a preferred embodiment of the invention, the probe means comprises a pair
of
elongate metal probe members fixed to the internal bore of a male camlock
fitting on the
hose, with the probe members generally parallel to the axis of the fitting and
disposed
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fully within the internal diameter of the fitting. The check valve is
preferably a
Duo-Chek valve, as manufactured by Crane Co., or a similar valve which like
the
Duo-Chek comprises a pair of semi-circular plates which are rotatable about a
common
diametrical axis, with biasing means (typically comprising a spring) to bias
the plates
toward the closed position, with the circumferential edges of the semi-
circular plates in
sealing engagement with the bore of the check valve body. The probe members
are
spaced and arranged such that when the hose is being coupled to the outlet
pipe, they will
push against the downstream sides of the semi-circular plates of the check
valve, forcing
them to the open position in which fluid can flow from the upstream side of
the check
valve through the check valve.
In alternative embodiments, the probe means may comprise only one probe
member, which will act against only one of the semi-circular plates of the
check valve.
This single-probe embodiment may also be used in conjunction with other types
of check
valves such as a butterfly-type check valve having a single, spring-biased
circular plate
which swivels about a diametrical axis.
In one aspect, therefore, the present invention provides an assembly including
probe means fixed to the end of a hose element, plus a check valve installed
in a pipe
(such as the outlet pipe of an oil storage tank), with the hose and pipe being
adapted for
liquid-tight sealing using a non-rotating type of coupling such as a camlock
coupling.
In another aspect, the present invention provides a male camlock fitting
incorporating probe means generally as described above. In another aspect, the
invention
provides a tubular adapter incorporating probe means as described, with a male
fitting on
one end for connection to an outlet pipe, and with a female fitting on the
other end for
connection to the end of a hose. This latter embodiment facilitates use of the
present
invention with existing hoses without needing to modify the hoses, even if
they have end
fittings that are not compatible with the fitting on the outlet pipe to which
connection is
desired to be made.
Although the fitting on the end of the hose will typically be a male fitting
regardless of the coupler type, and the fitting on the outlet pipe will
typically be a female
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fitting, persons skilled in the art will appreciate that the present invention
can be readily
adapted for use with the alternative fitting combinations (e.g., female
fitting on the hose,
with a male fitting on the outlet pipe).
BRIEF DESCRIPTION OF THE DRAWINGS
Embodiments of the invention will now be described with reference to the
accompanying figures, in which numerical references denote like parts, and in
which:
FIGURE 1 is an elevation of a liquid storage tank having an outlet pipe
incorporating a shut-off valve plus a check valve downstream of the shut-
off valve, with the outlet pipe being adapted for coupling with a hose
incorporating probe means for actuating the check valve, in accordance
with a first embodiment of the present invention.
FIGURE 2 is an isometric exploded view of the hose, probe means, and
outlet pipe shown in Fig. 1
FIGURE 3 is a cross-section through the hose, probe means, and outlet
pipe as in Fig. 1, with the hose disconnected from the outlet pipe, and with
both the check valve and the shut-off valve in their closed positions.
FIGURE 4 is a cross-section through the hose, probe means, and outlet
pipe as in Fig. 1, with the hose coupled to the outlet pipe, with the probe
means having actuated the check valve to an open position, and with the
shut-off valve still in its closed position.
FIGURE 5 is a cross-section as in Fig. 4 but with the shut-off valve
having been actuated to its open position, thus allowing liquid flow
through the outlet pipe into the hose.
FIGURE 6 is a cross-section generally as in Fig. 5 but with the hose
having been uncoupled from the outlet pipe so as to disengage the probe
means from the check valve, thereby closing the check valve and
preventing liquid flow out of the outlet pipe despite the shut-off valve
remaining in the open position.
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DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
The various embodiments of the invention may be best understood with reference
to the Figures, which illustrate a typical liquid storage tank T having an
outlet pipe 40
projecting through a lower region of the tank wall TW. Outlet pipe 40
incorporates a
shut-off valve 42 (shown for exemplary purposes as a ball valve) with an
actuator handle
44. Downstream of shut-off valve 42, outlet pipe 40 also incorporates a check
valve 60,
which in preferred embodiments will be of a type comprising a pair of semi-
circular
plates 64 which are rotatable about a common diametrical axis 62, and which
are biased
toward a closed position (i.e., permitting no fluid flow). The outer end of
outlet pipe 40
has a female pipe fitting 50 of a suitable type, which in preferred
embodiments will be a
female camlock fitting.
A hose 30, for use in draining liquid from tank T through outlet pipe 40, has
a
male pipe fitting 12 (which will be a male camlock fitting in preferred
embodiments) for
liquid-tight coupling with female fitting 50. Male fitting 12 incorporates
probe means 10,
which in the illustrated and preferred embodiments comprises a pair of rigid
elongate
probe members 16 fixed to the inner bore 12A of male fitting 12, while leaving
a path for
fluid flow past or around probe means 10. In the illustrated embodiments,
probe members
16 are fixed to inner bore 12A of male fitting 12 by fixing one end of each
probe member
16 to a cross-member 14 extending diametrically across inner bore 12A (such
as, for
example, by welding or a threaded connection). However, persons skilled in the
art will
appreciate that various alternative ways of fixing probe members 16 to inner
bore 12A of
male fitting 12 can be readily devised using known design and fabrication
principles
techniques without departing from the scope of the present invention, provided
that there
remains a path for fluid to flow past probe means 10 and through male fitting
12.
In the particular embodiment shown in FIGS. 3-6, male fitting 12 is provided
with
an adaptor section 18 to facilitate use with a hose 30 having an existing pipe
fitting 20,
which might or might not be of a type engageable with female fitting 50 on
outlet pipe
40. Accordingly, a number of different styles of adaptor 18 could be provided
to ensure
that male fitting 12, incorporating probe means 10, can be used with different
types of
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hose-end fittings. Even when a hose end already has an existing fitting 20
which is
engageable with female fitting 50, it will typically be advantageous to use
male fitting 12
and adaptor 18 to avoid the need for modifying existing fitting 20 to
incorporate probe
means 10.
In FIGS 3-6, male fitting 12 is shown as a male camlock fitting with
circumferential groove 24. Accordingly, female fitting 50 is shown as a female
camlock
fitting with a pair of lever arms 52, each of which is rotatable about a
corresponding pivot
pin 51 as shown. Each lever arm 52 incorporates a cam element 53 adjacent to
the
corresponding pivot pin 51, for engagement within circumferential groove 24 of
male
camlock fitting 12. Similarly, existing male fitting 20 is shown as a male
camlock fitting
with circumferential groove 34, with adaptor 18 being incorporating a female
camlock
fitting with lever arms 22, each being rotatable about a corresponding pivot
pin 21 and
each having a cam element 23 for engagement within circumferential groove 34
of male
adaptor 18. FIG. 2 shows lever arms 22 and 52 in their open positions, while
FIGS 3-6
show lever arms 22 and 52 in the closed positions.
The use and operation of the coupling assembly of the present invention can be
readily understood with reference to FIGS. 3-6. Although these FIGS 3-6
illustrate the
particular embodiment describe immediately above, the operative principles are
fundamentally the same for other embodiments as well.
FIG. 3 illustrates the above-mentioned embodiment hose 30 with male camlock
fitting 12 and probe means 10 in an initial position, ready for engagement
with female
camlock fitting 50 connected to outlet pipe 40 in conjunction with check valve
60 and
shut-off valve 42. In FIG. 3, both check valve 60 and shut-off valve 42 are
closed.
In FIG. 4, male camlock fitting 12 has been engaged with female camlock
fitting
50, with lever arms 52 of female camlock fitting 50 having been rotated to
their closed
(i.e., locked) positions, with their cam elements 53 disposed within
circumferential
grooves 24 of male camlock fitting 12. The process of coupling male camlock
fitting 12
with female camlock fitting 50 has necessarily urged probe members 16 against
semi-
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circular plates 64 of check valve 60 and moved them to their open positions.
However,
flow through outlet pipe 40 is still prevented, because shut-off valve 42
remains closed.
In FIG. 5, the configuration of the assembly is the same as in FIG. 4 except
that
shut-off valve 42 has been opened, allowing flow through shut-off valve 42,
check valve
60, and into hose 30. This is the normal operative position for draining
liquid from
storage tank T.
FIG. 6 illustrates the situation where with the assembly configured as in FIG.
5,
male fitting 12 has been uncoupled from female fitting 50 without first
closing shut-off
valve 42. The uncoupling of male fitting 12 from female fitting 50 has
necessarily
caused male fitting 12 has been uncoupled from female fitting 50 probe means
10 to
disengage and withdraw from check valve 60, thereby causing check valve 60 to
be
returned to its closed position (due to the action of the check valve's
biasing means).
Therefore, liquid flow through outlet pipe 40 is prevented even though shut-
off valve 42
remains open.
In this patent document, any form of the word "comprise" is to be understood
in
its non-limiting sense to mean that any item following such word is included,
but items
not specifically mentioned are not excluded. A reference to an element by the
indefinite
article "a" does not exclude the possibility that more than one of the element
is present,
unless the context clearly requires that there be one and only one such
element. Any use
of any form of the terms "connect", "engage", "couple", "attach", or any other
term
describing an interaction between elements is not meant to limit the
interaction to direct
interaction between the subject elements, and may also include indirect
interaction
between the elements such as through secondary or intermediary structure.
Relational
terms such as "parallel", "perpendicular", "coincident", "intersecting", and
"equidistant"
are not intended to denote or require absolute mathematical or geometrical
precision.
Accordingly, such terms are to be understood as denoting or requiring
substantial
precision only (e.g., "substantially parallel") unless the context clearly
requires otherwise.
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of any form of the terms "connect", "engage", "couple", "attach", or any other
term
describing an interaction between elements is not meant to limit the
interaction to direct
interaction between the subject elements, and may also include indirect
interaction
between the elements such as through secondary or intermediary structure.
Relational
terms such as "parallel", "perpendicular", "coincident", "intersecting", and
"equidistant"
are not intended to denote or require absolute mathematical or geometrical
precision.
Accordingly, such terms are to be understood as denoting or requiring
substantial
precision only (e.g., "substantially parallel") unless the context clearly
requires otherwise.
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