Note: Descriptions are shown in the official language in which they were submitted.
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TITLE: System and Method for Preventing Tanker Truck Overfill
FIELD
[0001] This disclosure relates to the field of overflow protection systems for
tanker trucks. In particular
the disclosure relates to systems that prevent storage tanks from being
overfilled during the loading
procedure, thereby preventing spills.
BACKGROUND
[0002] Tanker trucks are used to transport a wide variety of liquids, such as
crude oil, gasoline,
kerosene, waste oil, milk, and other liquids. Because of the hazardous nature
of many liquids that are
transported in such trucks and because of the costs associated with both loss
of product and spill
cleanup, it is desirable to prevent overfill of the tank. An overfill event
can result in a spill of oil,
gasoline, or other hazardous materials. Such spills can be very costly to
clean up and may cause
environmental damage if the spill is of significant quantity and/or occurs in
an environmentally sensitive
location.
[0003] Several devices have been installed on tanker trucks in order to
attempt to solve the overfill
problem. For example, trucks have been equipped with sight gauges that the
driver must watch in order
to visually identify when the tank is approaching its maximum capacity.
However, sight gauges are
susceptible to human error. For example, if a driver walks away from the
truck, becomes injured, falls
asleep, or becomes distracted while the loading process is underway; the sight
gauge will not be
monitored and the tank may overfill.
[0004] Other systems have used digital gauges. A digital gauge, when
operative, may provide the driver
with a numeric reading of the percentage of fill or the number of gallons that
are in the tank. Optionally,
an alarm may sound once the level of fluid in the tank reaches a predetermined
level. However, digital
gauges are prone to failure, especially when installed on trucks that must
drive on the bumpy roads,
gravel areas and/or other rough terrain that is common in oil well fields,
tank yards and other loading
areas. In addition, even if a digital gauge does not completely fail, it may
provide incorrect readings due
to the jostling that it endures during transportation. When readings are
inaccurate, frustrated drivers
may physically bypass or cut the wires associated with the gauge, thus
rendering the system useless.
Further, even a perfectly functioning digital gauge or alarm system is only
effective if continuously
monitored by the driver.
[0005] Various attempts have been made to provide liquid tank monitoring and
overflow protection
systems and apparatuses. Examples of these attempts can be seen by references
such as U.S. Patent No.
4,903,672; U.S. Patent No. 5,052,223; U.S. Patent No. 5, 187,979; U.S. Patent
No. 5,226,320; U.S. Patent
No. 5,507,326, U.S. Patent No. 5,632,302; U.S. Patent No. 6,154,144; U.S.
Patent No. 6,229,448, U.S.
Patent Application 2005/0268971,and EP Patent No. 1,676,063.
[0006] Many of these systems are used only with stationary tanks and are
unsuited for use with tanker
trucks. In addition, while many such systems monitor or measure fluid levels,
they are not capable of
automatic operation in response to fluid conditions. Furthermore, many such
systems are not able to be
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incorporated with existing tanker truck electrical and mechanical components.
Also, many such systems
do not provide additional manual operation and data readout beyond fluid level
to allow a user to make
educated decisions while filling a tank.
[0007] Accordingly, there exists a desire for an overflow protection device
that can be used with an
existing tanker truck to provide automatic overfill protection without
requiring direct monitoring or
manual intervention by a user.
SUMMARY
[0008] A first embodiment is a control system for preventing overfill of a
tanker truck, the tanker truck
having a tank for containment of a fluid cargo, at least one control valve for
regulating a flow of fluid
into the tank, a level sensor for detecting a level of fluid within the tank,
and a fluid transfer pump for
transferring the fluid cargo into the tank, said control system comprising:
(a) a sensor to detect when the level of fluid in the tank has reached a
predetermined level; and
(b) a control module to shut down the pump in response to the level of fluid
in the tank reaching the
predetermined level.
[0009] In an embodiment, the control system further comprises a control device
to close the at least
one control valve in response to the level of fluid in the tank reaching the
predetermined level.
[0010] In an embodiment, the tanker truck comprises a parking brake and the
control system is
arranged to automatically activate in response to application of the parking
brake.
[0011] In a further embodiment, the control system comprises an emergency
stop, wherein activation
of the emergency stop causes the pump to shut down irrespective of the level
of fluid in the tank.
[0012] In an embodiment, the control system comprises a system override,
wherein activation of the
system override prevents the control system from shutting down the pump or
closing the at least one
control valve, irrespective of the level of fluid in the tank.
[0013] In another embodiment, the control system comprises a communication
device for relaying a
system status to a communication system.
[0014] In an embodiment, the control module is arranged to shut down the pump
by shutting down the
truck's engine, thereby cutting power to the pump.
[0015] In an embodiment, the control system comprises at least one indicator
to indicate a system
status. In a further embodiment, the at least one indicator is a visual
indicator or an audible indicator.
[0016] An additional embodiment is a control system for preventing overfill of
a tanker truck, the
tanker truck having a tank for containment of a fluid cargo, at least one
control valve for regulating a
flow of fluid into the tank, a level sensor for detecting a level of fluid
within the tank, an engine control
unit for regulating the operation of the engine of the truck, and a fluid
transfer pump powered by the
engine, said control system comprising:
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a controller arranged to receive a tank-full signal from the level sensor in
response to the level of fluid in
the tank reaching a predetermined level, said controller arranged to send a
shut-down-engine signal to
the engine control unit in response to the tank-full signal, thereby causing
the engine to shut down.
[0017] In a further embodiment, the controller is arranged to receive an
engine-off signal from the
engine control unit once the engine has been shut down and to send a close-
valve signal to the at least
one control valve in response to the engine-off signal.
[0018] In an additional embodiment, the controller is configured to delay
sending the close-valve signal
for a predetermined period of time after receiving the engine-off signal from
the engine control unit.
[0019] In an embodiment, the fluid is transferred into the tank by a fluid
transfer member and the
predetermined period of time is sufficient to allow the pressure within the
fluid transfer member to
subside to a level sufficiently low to ensure that closing the control valve
will not cause a spill of fluid
from the fluid transfer member.
[0020] In an embodiment, the tanker truck comprises a parking brake and the
control system
comprises a switch that closes in response to engagement of the parking brake
and opens in response to
release of the parking brake, said switch activating the system when in the
closed position and
deactivating the system when in the open position.
[0021] In an embodiment the control system comprises an emergency stop
mechanism, wherein
activation of the emergency stop mechanism causes the system to send the shut-
down signal to the
engine control unit irrespective of the level of fluid in the tank.
[0022] In an embodiment the control system comprises a system override for
preventing the control
system from shutting down the pump or closing the at least one control valve,
irrespective of the level
of fluid in the tank. In a further embodiment the system override is manually
activatable. In an
additional embodiment, the control system further comprises at least one
override indicator to indicate
when the system override is active. In yet another embodiment, the override
indicator is an audible
alarm.
[00231 In an embodiment, the control system comprises at least one system
status indicator. In a
further embodiment, the at least one system status indicator is a visual
indicator or an audible indicator.
[0024] In an embodiment, the control system comprises a communication device
for relaying a system
status to a communication system. In yet another embodiment, the control
system comprises a
communication device for relaying a system status to a remote communication
system. In an
= embodiment, the system status is system active, system fired, or system
override.
[0025] In an embodiment of the control system, the controller comprises a main
control module and an
engine control module, wherein the main control module is arranged to receive
the tank-full signal and
to send the tank-full signal to the engine control module, the engine control
module is arranged to relay
the tank-full signal to the engine control unit and to receive the engine-off
signal from the engine
control unit, the engine control module is arranged to relay the engine-off
signal to the main control
module, and the main control module is arranged to send the close-valve signal
to the at least one
control valve.
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[0026] In a further embodiment, the main control module is electrically joined
to a first electrical
connector and the engine control module is electrically joined to a second
electrical connector, said first
and second electrical connectors arranged to couple together, thereby
electrically connecting the main
control module and the engine control module.
[0027] Yet another embodiment is an automated method for preventing overfill
of a tanker truck, the
tanker truck having a tank for containment of a fluid cargo, at least one
control valve for regulating a
flow of fluid into the tank, and a fluid transfer pump for transferring the
fluid cargo into the tank
through a fluid transfer member, said method comprising:
(a) determining a level of fluid within the tank; and
(b) shutting down the pump once the fluid has reached a predetermined level.
[0028] In an additional embodiment, the method further comprises a step of
closing the at least one
control valve after the pump has been shut down.
[0029] In an embodiment the method further comprises a step of waiting for a
period of time between
the steps of shutting down the pump and closing the at least one control
valve. In a further
embodiment, the period of time is a period of time sufficient to allow the
pressure in the fluid transfer
, member to subside to a level that will not cause a spill once the at
least one control valve is closed.
[0030] In an embodiment of the method, the pump is powered by the engine of
the truck and the step
of shutting down the pump is accomplished by shutting down the engine of the
truck.
[0031] In yet another embodiment of the method, the predetermined level is
higher than the legal fill
limit for the tank and lower than the full volume of the tank.
BRIEF DESCRIPTION OF DRAWINGS
[0032] Figure 1 depicts a side view of an embodiment of a control system for
preventing overfill of a
tanker truck, installed on a tanker truck.
[00331 Figure 2 depicts a front view of an embodiment of a main control
module.
[00341 Figure 3 depicts an electrical schematic block diagram showing the
major electrical components
of an embodiment of a main control module.
[0035] Figure 4 depicts an electrical schematic block diagram showing the
major electrical components
of an embodiment of an engine control module.
[0036] Figure 5 depicts a flow chart of a series of events that may occur
during a tank-filling operation
with a threatened overfill prevented by an embodiment of the control system.
[0037] Figure 6 depicts a flow chart detailing the series of events that
occurs once the fluid reaches the
predetermined level during a tank-filling operation with a threatened overfill
prevented by an
embodiment of the control system.
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DESCRIPTION
[0038] Throughout the following description specific details are set forth in
order to provide a more
thorough understanding to persons skilled in the art. However, well known
elements may not have been
shown or described in detail to avoid unnecessarily obscuring the disclosure.
Accordingly, the
description and drawings are to be regarded in an illustrative, rather than a
restrictive, sense. Further,
where considered appropriate, reference numerals may be repeated among the
figures to indicate
corresponding or analogous elements.
[0039] Provided generally is a control system for preventing overfill of a
tanker truck, said system
configured to shut down the fluid transfer pump and close the entry and exit
valves on the tank once
the fluid in the tank has reached a predetermined level. The system comprises
a level sensor for
detecting when the level of fluid within the tank has reached the
predetermined level. The system
further comprises a control device to shut down the pump once the fluid has
reached the
predetermined level. The system may additionally comprise a control module to
shut down a control
valve on the tank in response to a signal that the engine has been shut down.
The control system is
suitable for use with a tanker truck hauling any type of fluid. Examples of
fluids commonly hauled in
tanker trucks include gasoline, diesel, oil, kerosene, and milk.
[0040] An embodiment of the system installed on a tanker truck is shown in
Figure 1. In the illustrated
embodiment, the tanker truck comprises a cab comprising an engine compartment
124 and a trailer
comprising a tank 112 for containing a fluid 110. Included within the engine
compartment 124 is an
engine control unit 122; also known as an engine control module (ECM),
powertrain control module
(PCM) or vehicle control module (VCM); which is an electronic control unit
that regulates operation of
the truck's engine. Included within the cab of the truck is a parking brake
120. The system comprises an
engine control module 126 that is arranged to communicate with the engine
control unit 122. The
engine control module 126 is further arranged to receive a signal from the
parking brake 120, such that
the system is activated into an active state, also referred to as a ready
state, by engagement of the
parking brake. The tanker truck further comprises a fluid transfer pump (not
shown) that is used to
pump fluid into the tank 112 when the tank is being filled. The fluid transfer
pump is powered by the
truck's engine, such that shutting down the engine shuts down the fluid
transfer pump.
[0041] In the embodiment depicted in Figure 1, the trailer of the tanker truck
comprises a tank 112.
Flow of fluid into the tank is regulated by one or more control valves 104,
which may be controlled by
solenoid valves 102. In an embodiment, the trailer comprises at least one
entry valve and at least one
exit valve, wherein both the entry and exit valves are operable in response to
the control system. The
trailer further comprises a level indicating system 106 that may comprise an
inductive float sensor 108
or other proximity switch to determine when the fluid in the tank reaches a
predetermined fill level.
The predetermined level may be any level selected by a user. For example, the
predetermined level
may be set at or near the legal fill limit of the tank. As another example,
the predetermined fill level
may be set beyond the legal fill limit of the tank, but below the level at
which the tank will begin to
overflow.
[0042] The control system comprises a main control module 100 that may be
mounted on the trailer.
When the system is installed and in use, the main control module 100 and the
engine control module
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122 are in communication allowing signals to be sent back and forth between
the two modules. In the
illustrated embodiment, the engine control module 122 and the main control
module 100 are connected
by a wiring 114 and coupled by male 118 and female 116 connectors.
[0043] The main control module 100 comprises a level sensor for detecting when
the level of fluid in
the tank has reached a predetermined fill level. In an embodiment, the level
sensor detects when the
level of fluid in the tank has reached the predetermined fill level by
receiving a tank-full signal from the
inductive float sensor 108. Once the tank-full signal has been received by the
main control module 100,
a signal is sent to the engine control module 122. The engine control module
122 is arranged to receive
the tank-full signal from the main control module 100 and in response to send
a shut-down-engine
signal to the engine control unit. In response to the shut-down-engine signal,
the engine control unit
shuts down the engine, thereby shutting down the fluid transfer pump and
stopping active transfer of
fluid into the tank.
[0044] Once the engine has been shut down by the system, an engine-off signal
is sent from the engine
control module to the main control module. In response to the engine-off
signal, the main control
module sends a close-valve signal to the solenoid valves 102 which in turn
causes the at least one
= control valve 104 to close. In an embodiment, the at least one control
valve is an air operated control
valve to which the supply of control air is controlled by the solenoid valve
102, though the system may
be used with any type of valve that can be operated in response to a signal
from the main control
module. In a further embodiment, the tank comprises entry and exit control
valves, both of which are
closed in response to the close-valve signal.
[0045] Once the engine has been shut down, there may still be considerable
pressure in the pipe, hose,
or other fluid transfer member that is being used to transfer fluid into the
tank. If this pressure is not
reduced before closing the at least one control valve 104, the pressure may
cause a breakage and/or
release of the fluid transfer member once the at least one control valve 104
is closed, leading to a spill of
fluid. To ameliorate this problem, the system may be configured to introduce a
delay between receiving
the engine-off signal and sending the close-valve signal, the delay being for
a period of time sufficient to
allow the pressure to subside from pumping pressure to a level that will not
cause a spill once the at
least one control valve 104 is closed. In an embodiment, the delay is
sufficient to allow the pressure to
drop below pumping pressure. In another embodiment, the delay is sufficient to
allow the pressure to
drop to atmospheric pressure. The amount of time required for the pressure to
drop is expected to vary
depending on the transfer hose volume and the plumbing volume. For example,
the delay may range
from about 2 seconds to about 30 seconds, though shorter or longer delays are
possible.
[00461 Figure 2 shows an example of a main control module 100. The main
control module 100
comprises a system override switch 200, emergency stop button 208, audible
alarm 202, override
indicator light 204, system active indicator light 206, system-fired indicator
light 212, and a
weatherproof enclosure 210 to protect the internal electronic components of
the main control module
100. The system override switch allows a user to override the system. If the
system has been triggered,
also referred to as the system having been fired, by receiving a tank-full
signal from the level sensor, the
system will carry out the sequence of events described above to shut down the
engine and close the at
least one control valve. The at least one control valve will remain closed and
the engine will remain off
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until the system override is engaged by an operator. Once the operator has
engaged the system
override, then the truck can be restarted and any excess fluid can be pumped
off to the legal fluid level.
Once the fluid is at or below the legal level the operator should disengage
the override to reactivate the
system in its ready state. To discourage leaving the system override engaged,
the system may comprise
an audible alarm 202 that emits an audible signal as long as the override is
engaged. For example, the
audible alarm 202 may emit an intermittent buzz or beep as long as the system
is in override. The
system may further comprise a system override indicator light 204 that shines
or flashes as long as the
system is in override. The system may further comprise additional indicators
of system status. For
example, the system may comprise a system active indicator light 206 that
shines or flashes as long as
the system is active and the system may further comprise a system-fired
indicator light 212 to indicate
that the system has fired, causing engine shut-down and control valve closure.
[0047] The system may further comprise a communication device (not shown)
allowing the system to
communicate at least one system status to a remote communication device. For
example, the system
may comprise a communication device for communicating a system status via a
satellite, cellular, or GPS
network. In an embodiment, the system is configured to communicate when any of
the following
events occur: the system is activated, the system is fired, or the system is
put into override. In a further
embodiment, the system may be configured to communicate with an existing
communications network
used to track company assets such as GeoTrack or Geoforce. The communication
may be any type of
remote communication, including but not limited to, an SMS message, an e-mail,
an electronic alert, or a
telephone call.
[00481 Figure 3 depicts an exemplary wiring diagram for a main control module
wired to a trailer. The
main control module comprises a fire/bypass relay 306, bypass relay 308, and a
fire relay 310 electrically
connected to a ground 300, emergency stop 208, override 200, audible alarm
202, system active
indicator light 206, system fired indicator light 212, and a level sensor 304.
The main control module is
further connected to an electrical plug 116, allowing the main control module
to be electrically
connected to an engine control module.
[0049] Figure 4 depicts an exemplary wiring diagram for an engine control
module wired to a truck,
within the engine compartment. The engine control module comprises a cutout
relay 420, solenoid
control valve relay 422, and power relay 424 electrically connected to a
ground 300, the fire relay 310 in
the main control module, solenoid control valve 102, ignition power 410, feed
from parking brake 412,
feed to solenoid control valve 102, and battery power 416. The cutout relay
420 is connected to an
engine control unit 404 allowing the shut-down-engine and engine-off signals
to pass between the
engine control unit and the engine control module. The installed engine
control module further
comprises a parking brake switch 402 and an ISA fuse 418 that can isolate the
engine control module
from the truck battery 400 if the current exceeds the capacity of the fuse.
The main control module is
further connected to an electrical plug 118, allowing the main control module
to be electrically
connected to an engine control module.
[0050] Figure 5 depicts a flow chart of a series of eventsthat may occur
during a tank-filling operation
with a threatened overfill prevented by an embodiment of the control system.
In the depicted
embodiment, the control system is arranged to communicate system status to a
remote communication
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system; specifically sending a communication whenever the system is activated
and whenever the
system is fired.
[0051] Figure 6 depicts a flow chart outlining a series of events that occurs
once the fluid reaches the
predetermined level during a tank-filling operation with a threatened overfill
prevented by an
embodiment of the control system.
[0052] The truck to which the system is mounted may comprise a level gauge
having an inductive float
sensor 108 or other proximity switch. If so, a user can test the operation of
the system by placing a
metal wand or other metal object in close proximity to the proximity switch.
Doing so will activate the
level sensor, causing the system to fire. This allows the system to be readily
tested by a user, without
requiring the user to perform any strenuous operations or to enter the tank.
As such, the system can
be easily tested on a regular basis and be timely maintained or replaced if
not functioning properly.
[0053] The illustrated embodiments depict a system comprising a main control
module and an engine
control module, with the main control module being mounted to the trailer of a
tanker truck and the
engine control module being mounted within the cab of a trailer truck. This
arrangement allows for
multiple trailers and multiple cabs to be equipped with control modules,
allowing any cab and trailer
combination to be used, so long as the cab comprises an engine control module
and the trailer
comprises a main control module. However, other arrangements may be employed.
The system could
comprise a single control module or a plurality of modules that are arranged
to communicate with an
engine control unit, a level sensor, and at least one control valve. The
single control module, the main
control module plus engine control module, or the plurality of control modules
combined are each
collectively referred to as a controller.
[0054] The illustrated embodiments depict the system interacting with an
electronic engine control
unit to shut down the engine of the truck, thereby stopping the fluid transfer
pump. In a non-illustrated
embodiment, the control system may send a signal directly to a pump control
unit that regulates the
fluid transfer pump, allowing the fluid transfer pump to shut down without
requiring the engine to be
shut down. In this embodiment, a shut-down-pump signal would be sent to the
pump control unit by
the control system and a pump-off signal would be sent from the pump control
unit to the control
system in response to the fluid reaching a predetermined level.
[0055] Numerous specific details are set forth herein in order to provide a
thorough understanding of
the exemplary embodiments described herein. However, it will be understood by
those of ordinary skill
in the art that these embodiments may be practiced without these specific
details. In other instances,
well-known methods, procedures and components have not been described in
detail so as not to
obscure the description of the embodiments.
[0056] Further, while the above description provides examples of the
embodiments, it will be
appreciated that some features and/or functions of the described embodiments
are susceptible to
modification without departing from the scope of the invention as defined in
the appended claims.
Accordingly, what has been described above has been intended to be
illustrative of the invention and
non-limiting. It will be understood by persons skilled in the art that other
variants and
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modifications may be made without departing from the scope of the invention as
defined in the
appended claims.
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