Note: Descriptions are shown in the official language in which they were submitted.
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SYSTEMS AND METHODS FOR REMOTE TANK LEVEL MONITORING
FIELD OF THE INVENTION
The present invention relates generally to float type level gauges for
oilfield production tanks in which a cable has opposite ends depending inside
and
outside the tank so that movement of a float secured to the inside end of the
cable
under changes in the level of the tank contents moves an indicator at the
other end
of the cable along a gauge outside the tank to reflect the tank level, and
more
particularly to an improvement to such systems to enable tank level monitoring
from
remote locations.
BACKGROUND OF THE INVENTION
Conventional oilfield tank level gauges of the type briefly summarized
above make use of simple pulleys as the rollers or cable guides used to
support the
cable and form the direction changes in the cable's path from its indicator
portion
depending downward from atop the tank thereoutside to the float portion
depending
downward through the top of the tank. Typically, a first pulley is mounted
atop the
tank for rotation about a horizontal axis a short distance above where the
cable
depends down into the tank. A second pulley is mounted atop the tank for
rotation
about a second horizontal axis parallel to the first at a position adjacent
the
perimeter of the top of the tank. Placed over these two pulleys with the
indicator and
float at its opposite ends, the cable passes vertically upward from the float
through
an opening in the top of the tank, passes over the first pulley to extend
horizontally
to the second pulley, which it then passes over to hang vertically downward
along
the tank periphery to suspend the indicator. Rising of the float under an
increase the
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tank contents lowers the indicator outside the tank, which then indicates a
higher
level value by pointing to a marker labeled with a higher value further down
the chart
than the indicator's previous position. Lowering of the float under a decrease
of the
tank contents lift the indicator, which then points to a marker on the gauge
corresponding to a lower value reflective of a lower tank content level.
An obvious shortcoming of these simple mechanical tank level gauges
is that they are only viewable on site at the location of the tank, and
accordingly do
not provide any feedback on the content level of a tank to an owner, operator
or
other personnel when no one is on location. A number of remote tank level
monitoring solutions have previously been proposed and could likely be
employed
on these oilfield storage tanks, but these solutions are independent systems
that
require an entirely new installation on the tank and would likely make the
previously
installed float gauges on existing tanks redundant or obsolete.
Accordingly, there is a desire for a remote tank level monitoring
solution that can make use of conventional float gauge components to minimize
waste and maximize ease of installation.
SUMMARY OF THE INVENTION
According to a first aspect of the invention there is provided a remote
tank level monitoring system for a storage tank having an existing float-based
level
gauge comprising a cable, an upright gauge mounted outside the storage tank, a
float secured to a first end of the cable inside the storage tank, at least
one cable
guide atop the tank over which the cable passes from the first end to change
direction and hang a second end of the cable in front of the upright gauge
outside
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the tank, and an indicator secured to the second end of the cable to move
along the
upright gauge as the float moves with changes in content level of the tank to
cooperate with markings on the upright gauge to indicate the current content
level of
the tank at any point in time, the remote tank level monitoring system
comprising:
an image capturing device arranged to capture digital images that are
taken over time and each include a digital representation of at least a part
of the
upright gauge that includes a position at which the indicator is situated at a
respective point in time at which the digital image is captured; and
a communications device cooperatively linked to the image capturing
device to receive image data therefrom and transmit the image data over a
communications network to enable viewing of the digital representation from a
remote location to check the content level of the tank as measured at the
respective
point in time.
According to a second aspect of the invention there is provided a
remote tank level monitoring system for a storage tank, the system comprising:
a cable;
an upright gauge mounted outside the storage tank;
a float secured to a first end of the cable inside the storage tank;
at least one cable guide atop the tank over which the cable passes
from the first end to change direction and hang a second end of the cable in
front of
the upright gauge outside the tank;
an indicator secured to the second end of the cable to move along the
upright gauge as the float moves with changes in content level of the tank to
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cooperate with markings on the upright gauge to indicate the current content
level of
the tank at any point in time; and
an image capturing device arranged to capture digital images that are
taken over time and each include a digital representation of at least a part
of the
upright gauge that includes a position at which the indicator is situated at a
respective point in time at which the digital image is captured; and
a communications device cooperatively linked to the image capturing
device to receive image data therefrom and transmit the image data over a
communications network to enable viewing of the digital representation from a
remote location to check the content level of the tank as measured at the
respective
point in time.
Preferably the image capturing device is mounted on the indicator to
move along the upright gauge therewith.
Preferably the communications device is mounted on the indicator with
the image capturing device.
The communications device may be arranged to transmit the image
data to a server from which the image data is retrievable for viewing of the
digital
representation to check the content level of the tank.
Preferably the communications device is arranged to establish a
wireless connection to the communications network.
Preferably there is provided a battery power supply operable to power
the image capturing device.
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Preferably the battery power supply is also operable to power the
communications device.
Preferably the battery power supply is rechargeable.
There may be provided solar cells for charging the battery power
5 supply.
According to a third aspect of the invention there is provided a method
of remotely monitoring content level of a storage tank having a float-based
level
gauge comprising a cable, an upright gauge mounted outside the storage tank, a
float secured to a first end of the cable inside the storage tank, at least
one cable
guide atop the tank over which the cable passes from the first end to change
direction and hang a second end of the cable in front of the upright gauge
outside
the tank, and an indicator secured to the second end of the cable to move
along the
upright gauge as the float moves with changes in content level of the tank to
cooperate with markings on the upright gauge to indicate the current content
level of
the tank at any point in time, the method comprising:
capturing digital images over time which each include a digital
representation of at least a part of the upright gauge that includes a
position at which
the indicator is situated at a respective point in time at which the digital
image is
captured; and
transmitting image data over a communications network to enable
viewing of the digital representation from a remote location to check the
content level
of the tank as measured at the respective point in time.
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Preferably the method includes capturing the digital images from a
view point carried on the indicator.
The method may include transmitting the image data to a server and
providing access to the server to facilitate retrieval of the image data
therefrom for
viewing of the digital representation to check the content level of the tank.
The method preferably includes transmitting the image data over a
wireless connection to the communications network.
According to a fourth aspect of the invention there is provided a
method of upgrading a tank level monitoring system to enable remote tank level
monitoring for a storage tank having an existing float-based level gauge
comprising
a cable, an upright gauge mounted outside the storage tank, a float secured to
a first
end of the cable inside the storage tank, at least one cable guide atop the
tank over
which the cable passes from the first end to change direction and hang a
second
end of the cable in front of the upright gauge outside the tank, and an
indicator
secured to the second end of the cable to move along the upright gauge as the
float
moves with changes in content level of the tank to cooperate with markings on
the
upright gauge to indicate the current content level of the tank at any point
in time, the
method comprising:
setting up an image capturing device and a communications device
cooperatively linked thereto so as to be operable to capture digital images
over time
and to transmit image data over a communications network to enable viewing of
the
digital images from a remote location;
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positioning the image capturing device at a position from which the
digital images will each include a digital representation of at least a part
of the
upright gauge that includes a position at which the indicator is situated at a
respective point in time at which the digital image is captured.
Preferably the method includes positioning the image capturing device
on the indicator so as to be movable therewith along the upright gauge.
BRIEF DESCRIPTION OF THE DRAWINGS
In the accompanying drawings, which illustrate a exemplary
embodiments of the present invention:
Figure 1 is a schematic perspective view of an oilfield storage tank with
a conventional float type tank level gauge.
Figure 2 is an enlarged elevational view of a portion of the tank level
gauge of Figure 1.
Figure 3 is a partial elevational view of a remote tank level monitoring
system produced by upgrading the conventional float type tank level gauge of
Figures 1 and 2.
DETAILED DESCRIPTION
Figures 1 and 2 illustrate the conventional oilfield tank level gauge of
the type briefly summarized in the background section above. A first pulley 10
is
mounted atop the tank 12 for rotation about a horizontal axis a short distance
above
where the cable 14 depends down into the tank's interior. A second pulley 16
is
mounted atop the tank for rotation about a second horizontal axis parallel to
the first
at a position adjacent the perimeter 18a of the top 18 of the tank 12. Placed
over
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these two pulleys with the indicator 20 and float 22 at its opposite ends, the
cable
passes vertically upward from the float through an opening in the top of the
tank,
passes over the first pulley to extend horizontally to the second pulley,
which it then
passes over to hang vertically downward along the tank's peripheral wall 24 to
suspend the indicator along the vertical gauge 26 mounted on the wall 24.
Rising of
the float 22 under an increase the tank contents lowers the indicator 20
outside the
tank, which then indicates a higher level value by pointing to a marking
labeled with
a higher value further down the chart than the marking at indicator's previous
position. Lowering of the float under a decrease of the tank contents lift the
indicator, which then points to a marker at a higher elevation on the gauge
labeled
with a lower numerical value reflective of a lower tank content level.
Figure 3 shows a float type tank level gauge of the type shown in
Figures 1 and 2 having been modified according to the present invention to add
a
battery powered electronic unit 100 that is mounted on the indicator 20 to
move
therewith up and down the gauge 26 under changes in the content level of the
tank.
Within a single housing, the electronic unit incorporates an image capturing
device
having digital photograph functionality and a communications device operable
to
wirelessly connect to a mobile communications network to communicate with a
computer network, for example the internet, in order to transmit image data
from the
image capturing device to a server set up to store the images. Tank monitoring
personnel can then access the stored digital images captured at the tank site.
The
image capturing device is positioned to aim its lens toward the gauge 26 so
that
images captured each show the "reading point" feature of the indicator (the
part of
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the indicator used as the to indicate a particular level on the gauge by
aligning with
or pointing to a level marker thereon) and the portion of the gauge behind
this
feature, including the particular value marking on the gauge that is being
referred to
by the indicator. Accordingly, when the owner, operator or other party
responsible
for the tank accesses the server using a desktop computer, laptop computer,
smartphone, PDA or other device operable to access the network, they will be
able
to visually see the latest reading on the gauge that was recorded by the image
capturing device.
The devices are setup to take and transmit digital photographs at
regular intervals of time so that the image stored on the server is updated
regularly
to reflect the most currently captured reading of the level gauge. File
transfer
protocol (FTP) may be used to transmit image data from tank level gauges at
multiple tanks to an FTP server, and web pages may be constructed to link to
the
collected images for easy viewing using a conventional web browser. Further
details
of the unit for capturing and transmitting the digital images are not
disclosed herein,
as existing equipment capable of the required functions is already known and
commercially available. For example, Colorado Video of Box 928, Boulder,
Colorado 80306, USA (http://www.colorado-video.com) has produced remote mobile
wireless internet cameras under the names Observer IV and Lookout V that have
features and functionality suitable for use in the present invention. These
units are
battery powered and use the Global System for Mobile Communications network
(GSM), thus being suitable for oilfield applications where on-site power and
wired
access to communications networks may not be available. The battery pack of
the
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Lookout V can be connected to a panel of solar cells for recharging. It may be
possible to mount a solar panel on the indicator to move therewith, or with a
long
enough cable between the solar panel and unit providing sufficient slack to
accommodate the movement of the electronic device up and down the gauge, the
5 solar panel may be mounted elsewhere on the tank or in a nearby area. The
aforementioned cameras can take and transmit pictures at selected intervals
and
turn off between scheduled image capturing and transmission events to conserve
power. The cameras also provide the alternative of connecting to an email
server to
enable sending of the digital images as email attachments instead of
transferring
10 them to the FTP server, thereby allowing the monitoring party to check the
images
whenever they check their email, instead of having to perform a separate
routine of
checking the FTP server or a website linked to the images thereon. In a normal
fashion, a "new email" notification on the user's computer or mobile device
may
inform them of an incoming message containing a tank level image attachment.
The option of sending the captured images as email attachments
demonstrates that the tank level monitory system of the present invention is
not
limited to storing the captured images on a server for later access. As
another
example, SingTel (http://www.singtel.com) has released a product called the
Mobile
LIVECam which could be used in the present invention. The camera uses a 3G SIM
card and a rechargeable battery and allows a user to place a video call to the
camera using a 3G compatible cellular phone, and once the video call
connection is
made the user can view real time video being captured by the camera and
operate
various controls of the camera, including pan, brightness, tilt and record
controls.
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Accordingly, the remote tank level system of the present invention may have an
automated image capture component that automatically records images based on
preconfigured or selected schedules or intervals for later retrieval of an
image by a
user of the system, or may alternatively employ a user-activated input-reliant
image
capture component that only records images when remotely instructed by a user.
Other user-activated systems could feature a unit that relies on an
incoming voice call or short message service (SMS) call from an authorized
user as
an input signal to capture an image. The captured image may be sent to an
email
address previously programmed into the unit, forwarded through the multimedia
messaging service (MMS) to a mobile device's assigned number previously
programmed into the unit, or sent to a server for storage and subsequent
retrieval by
a user. The cameras briefly summarized above not only feature the required
combination of image capture and data communication devices useful for the
present invention, but additionally offer automatic night mode activation that
senses
a lack of available visible light for image capture and accordingly activates
an
infrared light source to allow image capture in dimly lit ambient conditions.
Accordingly, embodiments of the present invention can be used day or night in
various weather conditions.
Battery operated image capture and wireless communication devices
are used in the above described systems to facilitate use of the remote tank
level
monitoring system at sites where mains power and wired access points to
communication networks are not available, as is typically the case for
oilfield storage
tanks. However, other storage tanks using float type gauges in power and
landline
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equipped regions may similarly be modified or upgraded to add remote
monitoring
functionality, without necessarily having to use battery power or wireless
communication. For example, the communications device could be provided by a
computer that has a wired internet connection and is coupled to an external
image
capture device such as a webcam mounted on the gauge indicator. This computer
could be operated as a server which can be accessed from remote locations over
the internet to access the stored image, or could alternatively be equipped
with
software that captures an image frame from the webcam and then automatically
uploads the image to a remote server over the internet. The remote server can
be
used to store images from multiple tank level gauges. Even where the
communication device is relying on a wired telephone or internet network
connection, a wireless link may still be used between the communication device
and
the image capture device, for example using wireless data transfer protocols
used
by commercially available wireless webcams.
As an alternative to mounting of the image capture device directly on
the indicator of the float gauge, the device could alternatively be mounted at
a fixed
location from which it is operable to capture an image of the entire gauge, or
at least
enough of the marked portion thereof reflecting the possible range of tank
level
values that may be experienced during use. That is, the camera may be
positioned
a distance away from the tank and the gauge components thereof at a suitable
height and angle for capturing images of the gauge markings at a sufficient
resolution to enable clear reading of the marked gauge values when the images
are
reviewed. Accordingly, in an embodiment where a computer station forms a part
of
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the system, it may employ a built-in webcam as the image capture device is the
computer station is suitably positioned. In such an embodiment, both devices
may
be protected from the weather and elements in a protective housing or shelter.
In
another example employing a local computer station, the image capture device
may
be an IP camera installed on a wired or wireless network with the computer
station
and cooperable with a router of the network to allow access to the IP camera
from
remote locations via the internet. The Colorado Video devices mentioned herein
not
only benefit from their wireless, battery powered functionality for maximum
flexibility
in use at remote sites, but are also already designed to withstand
environmental
exposure. Outdoor use IP cameras suitable for use in weather exposed
environments are also commercially available. As described above in terms of a
solar panel, slack in power or data cables for embodiments in which the image
capturing device is mounted on the indicator for movement therewith can be
used,
but wireless installations provide a simpler, cleaner and more reliable system
in
which catching or tangling of a cable, or cable management equipment intended
to
eliminate such complications, are avoided.
Since various modifications can be made in my invention as herein
above described, and many apparently widely different embodiments of same made
within the spirit and scope of the claims without department from such spirit
and
scope, it is intended that all matter contained in the accompanying
specification shall
be interpreted as illustrative only and not in a limiting sense.
