Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
CA 02952501 2016-12-22
A SYSTEM AND METHOD FOR MONITORING THE STATUS OF AN ELECTRIC SUBMERSIBLE PUMP
Technical Field:
The present application relates to the monitoring of an electric submersible
pump. In particular,
this application relates to a system and method for monitoring one or more
parameters of an electric
submersible pump during operation and providing a visual indicator of the
status of the electric
submersible pump.
Background:
Electric submersible pumps may be used in a variety of applications for
pumping fluids which
are typically a mixture of liquids and solids. For example, submersible pumps
may be used in process
sumps and effluent ponds, and also for dredging. Electric submersible pumps
are designed to be
completely submerged in the fluid that is to be pumped, and include at least
one motor and at least one
bearing which are sealed against the surrounding environment, so as to prevent
the ingress of the
pumped fluid (otherwise referred to herein as the process fluid) into the
motor or the bearing of the
pump. Inside the sealed motor and bearing components, there is oil so as to
adequately lubricate the
motor and the bearing. One or more main pump seals separate the interior of
the motor and the
bearing from the process fluid in which the pump is submerged. Because the
motor and bearing of the
pump are hermetically sealed against the surrounding environment, the
temperature of the motor
within the pump's housing can rise to approximately 110 C to 130 C when the
motor is running.
The process fluids that may be pumped by submersible pumps may generally be
described as
including slurries or fluid and solid mixtures, which may contain, for
example, water mixed with mud or
water mixed with various different types of other particulates. From time to
time, larger solid objects
may be present in the process fluid, such as rocks. The pumps include
agitators which agitate the slurry,
and the resulting agitated mixture is then removed by the submersible pump.
The slurries being
pumped by submersible pumps are often opaque, to the extent that the pump,
when submerged in the
process fluid, may not be visible to the operator, even if the pumping
environment would otherwise
allow for a direct line of sight between the operator and the pump.
Submersible pumps may be difficult to maintain, as they are often operating in
harsh
environments where the components of the pump are often subjected to impact
forces by particulates
and other solids agitated within the process fluid being pumped. Because the
submersible pump may
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be submerged in an opaque slurry, an operator may not be able to detect when
the pump has suffered
physical damage as the result of, for example, impacts with solids in the
process fluid.
The most common modes of failure for submersible pumps include failure of the
seal which acts
as the barrier between the internal motor and bearing components of the pump,
and the surrounding
process fluid in which the pump has been submerged. Failure of the seal may
occur, for example, where
there is insufficient lubrication for the seal. Another mode of failure of the
seal may occur due to impact
damage between large objects and the agitator or the impeller of the pump,
which may cause lateral
movement in the shaft of the agitator or impeller and thereby cause failure of
the seal.
When the seal fails, water may ingress into the sealed motor and/or bearing
components of the
pump, or oil may leak from the motor and/or bearing components of the pump, or
some combination of
water ingress and oil leakage, may lead to failure of the pump. For example,
water that penetrates the
sealed motor component of the pump may cause the electric motor of the pump to
short out. Water
ingress into the sealed bearing component will interfere with the proper
lubrication of the bearing,
eventually causing the bearing to seize and fail. In other possible modes of
failure, where oil leaks out of
the motor and/or bearing components, reduced oil levels may result in
insufficient lubrication of the or
motor and/or bearing, eventually causing seizure of the moving parts of the
motor and/or bearing
components. When such failure modes occur, it may take some time between the
point at which the
seal failed, and the point at which the motor and/or bearing become damaged to
the extent of requiring
repair and replacement. Furthermore, it is difficult to determine when
preventative maintenance of a
submersible pump may be required, as examining the condition of the pump and
in particular, the
integrity of the seals, normally requires physically removing the submersible
pump from the process
fluid so as to conduct the examination. Additionally, even once the pump has
been removed from the
process fluid, diagnosing whether water ingress and/or oil leakage has
occurred requires disassembly of
the sealed motor and/or bearing components of the pump. As such maintenance
work is labour-
intensive and requires temporary cessation of the pumping operations while the
pump is removed from
service for maintenance, it is often the case that such maintenance work does
not commence until the
pump has failed.
Thus, there is a need for monitoring the integrity of the seals of an electric
submersible pump,
so as to detect when a seal initially fails and providing some type of visual
indicator to the operator
signalling that maintenance or repair of the pump is required.
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Summary:
In one aspect of the present disclosure, a system for monitoring the status of
an electric
submersible pump is provided, which may include water content sensors capable
of measuring the
amount of water or other contaminants relative to the amount of oil within the
hermetically sealed
motor or bearing components of the electric submersible pump, and emitting a
visual indicator to the
operator when the measured content of water or other contaminants exceeds a
threshold indicating
that seal failure is imminent or has occurred. In some embodiments, the system
may include a visual
indicator that includes a light display mounted to the exterior surface of the
pump housing and/or to the
power cable of the submersible pump. In other embodiments, the light display
may be mounted against
the interior surface of the pump housing against a transparent or translucent
window that enables an
operator to view the light display from the exterior of the pump through the
transparent or translucent
window. The light display may change colours to indicate a particular status
of the submersible pump
and whether the pump requires servicing; in some embodiments, the light
display may also include the
display of an alphanumeric code rather than, or in addition to, changing
colours, so as to provide more
specific information about the operating condition and status of the
submersible pump, such as
conveying information about the water content within the sealed motor and/or
bearing portions of the
pump and an indication of, for example, elevated temperatures in the bearing
or the pump motor.
In another aspect of the present disclosure, a method for monitoring the
status of an electric
submersible pump during operation is provided, which may include providing one
or more sensors for
measuring one or more parameters of the operating condition of the pump, the
one or more sensors in
communication with a controller and the controller in communication with at
least one visual indicator,
wherein the one or more sensors measure the one or more parameters at a pre-
determined rate and
communicate the measured values to the controller, wherein the controller
correlates the measured
values of the parameters against a plurality of statuses of the submersible
pump, and the controller then
controls the visual indicator to output a signal conveying the operating
status of the submersible pump.
In some embodiments of the present disclosure, the one or more sensors may be
selected from a group
comprising: contact sensor for measuring water content, oil level sensor,
thermometer, electrical
sensor, vibration sensor, tachometer. In other embodiments of the present
disclosure, the method may
further include the controller transmitting the measured values of the one or
more parameters to a data
storage unit, which data may be further utilized in diagnosing the operating
condition of the
submersible pump.
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Brief Description of the Figures
FIG. 1 is a front elevation view of light displays mounted to the motor
section of an electric submersible
pump in accordance with some embodiments of the present disclosure.
FIG. 1A is a front elevation view of an embodiment of the present disclosure,
showing the motor section
of an electric submersible pump illustrated in FIG. 1 mounted to the rest of
the electric submersible
pump in accordance with an embodiment of the present disclosure.
FIG. 1B is a front perspective view of the motor section of an electric
submersible pump mounted to the
rest of the electric submersible pump, in an embodiment in which the motor
section does not include an
oil reservoir having translucent or transparent windows.
FIG. 2 is a logic flow diagram, showing a process for monitoring the status of
an electric submersible
pump in accordance with an embodiment of the present disclosure.
FIG. 3 is a logic flow diagram, showing an alternate process for monitoring
the status of an electric
submersible pump in accordance with an embodiment of the present disclosure.
FIG. 4 is a system flow chart illustrating the monitoring system in accordance
with an embodiment of the
present disclosure.
FIG. 5 is a system flow chart illustrating the master node of the monitoring
system in accordance with an
embodiment of the present disclosure.
FIG. 6 is a process diagram illustrating the master node of the monitoring
system in accordance with an
embodiment of the present disclosure.
FIG. 7 is a system diagram illustrating the sensor node control board of the
monitoring system in
accordance with an embodiment of the present disclosure and also including a
photograph of a sensor
node board.
FIG. 8 is a process diagram illustrating the sensor node of the monitoring
system in accordance with an
embodiment of the present disclosure.
FIG. 9 is a system diagram illustrating the lighting node of the monitoring
system in accordance with an
embodiment of the present disclosure.
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FIG. 10 is a process diagram illustrating the lighting node of the monitoring
system in accordance with
an embodiment of the present disclosure.
FIG. 11 is a circuit diagram illustrating the power supply of the monitoring
system in accordance with an
embodiment of the present disclosure.
FIG. 12 is a front elevation drawing of the light display repeater bead of the
monitoring system in
accordance with an embodiment of the present disclosure.
FIG. 13 is a circuit diagram of the remote analog sensor board of the
monitoring system in accordance
with an embodiment of the present disclosure.
FIG. 14 is a circuit diagram of the filtering and control board of the
monitoring system in accordance
with an embodiment of the present disclosure.
FIG. 15 is a circuit diagram of the sensor and control board of the monitoring
system in accordance with
an embodiment of the present disclosure.
FIG. 16 is a circuit diagram of the lighting string control board of the
monitoring system in accordance
with an embodiment of the present disclosure.
Detailed Description
In Fig. 1, the motor section of an electric submersible pump 10 is shown. The
electric
submersible pump 10 includes a power cable 12 connected to the lead cover 20.
The electric
submersible pump 10 further includes a motor housing 16 and an oil reservoir
30. In some
embodiments of the present disclosure, such as illustrated in Fig. 1, the oil
reservoir 30 may include
transparent or translucent (collectively herein, "translucent) windows 32,
which enables a person
viewing the oil reservoir 30 to quickly and easily determine the status of the
oil, including possible
contamination of that oil, and the level of the oil, contained within the
sealed oil reservoir 30 by means
of a visual inspection. For example, in some embodiments of the present
disclosure, the oil reservoir 30
may comprise a frame 31, for example including annular rings 31a and 31b,
supported by a plurality of
vertical bars 31c between annular rings 31a, 31b. The frame 30 supports a
plurality of translucent
windows 32. The windows 32 may be constructed, for example, of polycarbonate,
polyurethane, acrylic,
glass, or other suitable materials known or that will be known to a person
skilled in the art. In other
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embodiments, the oil reservoir of the motor section 10 may not include
transparent or translucent
windows, as shown Fig. 1A. Figure 1A is an example of the HNS-Series electric
submersible pumps
distributed by Toyo Pumps North AmericaTM, also trading under the name Hevvy
PumpsTM, the HNS-
Series pumps being described for example in brochures available at the website
address
hevvypumps.com. The system for monitoring an electric submersible pump, as
described in the present
disclosure, may be employed on an existing electric submersible pump, such as
the HNS-Series pumps
distributed by Toyo Pumps North America. As would be known to a person skilled
in the art, an HNS-
Series pumps are illustrative of the electric submersible pumps for which the
monitoring system
described herein may be usefully deployed, and the system may for example
utilize sensors and other
pump components already integrated into such existing electric submersible
pumps.
In some embodiments of the present disclosure, a visual display, such as for
example a light
display repeater bead 14, may be mounted to the power cable 12. In addition
to, or as an alternative to,
the light display bead 14 mounted to the power cable 12, one or more visual
displays mounted to the
electric submersible pump 10 may include one or more light display strips 34a,
34b. In some
embodiments, the light display strips 34a, 34b and/or the light display
repeater bead 14 may be
constructed of LED strips or arrays. In some embodiments, the light display
repeater bead 14 and/or the
light display strips 34a, 34b are capable of displaying a plurality of colors,
and/or changing colors, and/or
flashing in various patterns, and/or displaying alphanumeric characters, or a
combination of any of these
features, so as to indicate a different operating status or a change in the
operating status of the electric
submersible pump.
The light display strips 34a, 34b may, for example, be positioned on an upper
portion of the oil
reservoir 30, such as the position in which 34a is shown in Fig. 1 and on the
lower portion of exterior of
the oil reservoir 30, such as the position of 34b shown in Fig. 1. The
illustration of two light display strips
34a, 34b in Fig. 1 is not intended to be limiting, as just a single light
display strip 34a or 34b may be
mounted on the exterior of the oil reservoir 30. Other positions on the
exterior surface of the electric
submersible pump for mounting the one or more light display strips 34 and are
within the scope of this
disclosure. For embodiments of the electric submersible pump incorporating a
translucent or
transparent portion of the oil reservoir 30, the one or more light display
strips 34 may be mounted to
the interior surface of the translucent/transparent portion and oriented
outwardly so as to be visible by
an operator viewing the exterior surface of the electric submersible pump.
Advantageously, mounting
the light display strips 34 within the interior of the oil reservoir 30
reduces the number of cables that run
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from the exterior to the interior of the pump housing, thereby reducing the
cable inlet areas of the
pump that must be hermetically sealed and may therefore be subject to the
various modes of
mechanical failure described above, with the overall effect of decreasing the
possibility of failure of the
hermetically sealed pump.
The light display repeater bead 14 may be positioned anywhere on the power
cable 12;
preferably, the light display repeater bead 14 may be positioned on a portion
of the power cable 12 that
is visible above the surface of the process liquid in which the pump 10 is
immersed. More than one bead
14, or other corresponding light display, may be provided along the cable so
that the status may be
viewed by an operator at multiple locations along the cable. Thus, for
example, the status indication
colour may be seen in a control room or at various locations between the pump
and the control room so
as to increase the likelihood that an operator will be warned of pump failure,
failed seals, etc. It will be
appreciated by a person skilled in the art that the light display is not
limited to being a light display
repeater bead positioned on the power cable, and may for example include a
light display molded into
the cable or otherwise integrally forming a portion of or being incorporated
into the cable 12.
In some embodiments of the present disclosure, a method is provided by which
the status of the
submersible pump is monitored by at least one sensor measuring at least a
first parameter of the
submersible pump, and a controller in communication with the at least one
sensor and the at least one
visual indicator receives data from the at least one sensor and then controls
the output to the visual
indicator which indicates a particular status of the submersible pump, the
status determined by the
controller based on the measurements of at least one parameter of the electric
submersible pump,
received from the at least one sensor.
As illustrated for example in Fig. 2, in some embodiments of the present
disclosure a method for
monitoring the status of an electric submersible pump includes starting the
pump 100 and determining
the frequency of the sampling for each sensor in step 102. Once the initial
frequency of the sampling for
each sensor has been determined, the controller will request data from all of
the scheduled sensors in
step 104, and then in step 106, the measured data received from the scheduled
sensors will be
compared against known values and their associated pump statuses, for each
parameter being
measured by the sensors, and correlate the measured values to a pump operating
status.
Once the measured values obtained from the scheduled sensors have been
correlated to the
operating status of the pump, the controller then determines, in step 108,
whether there has been a
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change in the status of the pump. In the event that the status of the pump has
not changed, the process
goes to step 110, in which the controller writes a report to a memory storage
device, and then the
method returns to repeat step 104, in which data is requested from all of the
scheduled sensors. In the
event that the controller determines, in step 108, that there has been a
change in status, the controller
will then generate a visual indicator output, whereby the output indicates the
status of the submersible
pump as determined by the controller step 112.
In some embodiments, in step 114, the controller writes a report to the memory
storage device,
regarding the change in status as determined by the controller, and then in
step 116, the controller
determines whether the measured value of any of the scheduled sensors exceeds
a threshold value.
The threshold value for each of the one or more sensors may be pre-determined
as a value of a
parameter of the motor which indicates there may be a problem with the pump
requiring service.
Where a measured value of a given parameter exceeds the pre-determined
threshold value, the
controller may increase the frequency of polling that particular sensor so as
to obtain more detailed
information about that parameter.
By way of example, in some embodiments of the present disclosure, the sensors
may include
contact sensors mounted within the bearing housing of the pump and/or within
the motor housing of
the pump, which contact sensors will measure the percentage of water content
present in the oil
contained in hermetically sealed pump housing. Typically, the contact sensors
may only need to be
polled, for example, at a frequency of once every five minutes or at some
other frequency, as the
change in water content may occur very gradually. However, once a threshold
value of water content
within the pump bearing or the motor housing, for example, reaches a pre-
determined threshold value,
such as one half of one percent (0.5%) water content, the sampling frequency
may then be increased to,
for example, polling the water content sensors every 30 seconds, so as to more
closely monitor changes
in the water content and thereby ensure that the controller is appropriately
generating visual indicators
that indicate to the user of the pump that the operating status of the pump is
becoming more critical
and in possible need of service. In this manner, by providing more accurate
information about the
operating status of the pump to the user, problems with water ingress into the
pump or oil leakage from
the pump may be detected prior to complete pump failure, thereby increasing
the likelihood of
repairing the pump before further damage occurs and, potentially, lowering the
cost of repair and/or
the downtime during which the pump is being serviced. The data may be used to
predict onset of
failure, for example, providing an operator with an estimated time-to-failure.
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Thus, at step 116 of the process, if the measured value of any one of the
parameters of the
pump exceeds the pre-determined threshold value, then in step 118 the
frequency of the sampling for a
particular sensor will be appropriately increased or decreased as may be
required. However, at step 118
of the process, if the measured value from any of the given sensors does not
exceed the pre-determined
threshold value, then the method returns to step 104 of requesting data from
all the scheduled sensors.
In some embodiments of the present disclosure, as shown for example in Fig. 3,
the process for
monitoring the status of the pump may also include a communication device
which is capable of
transmitting the reports generated by controller to an external device that
may be monitored by a user
of the pump or by a technician who needs to service the pump, for example. The
reports generated by
the controller may contain more information and detailed measurement data than
the information
about the status of the pump that is being indicated to a pump user by the one
or more light displays.
For example, such reports may include all of the detailed data collected by
each of the one or more
sensors, such as for example specific measured values of the water content,
the temperature of the
motor or the pump bearing, the current drawn by the pump motor, etcetera.
In some embodiments, the system may be provided with a communication device
which is
capable of transmitting reports to an external device that is readily
accessible by users of the pump
above the surface of the process fluid in which the pump is submersed. The
communication device may
include, for example, a wireless communication device such as a wireless
transmitter and receiver, or as
another example, data communication cables, such as shielded communication
cables preferably
adapted for transmitting data in an environment with a high amount of
electronic interference, the
communication cables running from the controller mounted in the lead cover 20
to the external device.
The external device may include, for example, a computer or server, a tablet
or smart phone, wherein
the external devices are loaded with pump monitoring software or applications.
Advantageously, the
communication device would enable the operator to obtain the reports generated
by the controller,
which may be located in the lead cover 20 of the pump, without having to
physically remove the pump
from the liquid in which it is submerged in order to physically access the
lead cover 20 so as to effect the
transfer of the data from the controller.
As illustrated in Fig. 3, some embodiments of the present disclosure include
providing processes
by which reports generated by the controller may be transmitted to other
devices for further review and
analysis. For example, such a method may include all of the steps described in
Fig. 2, and an additional
step occurring after the report generated by the controller has been written
to memory, at step 114
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whereby, at step 120, the controller determines whether the communication
device is presently
available for transmitting the report. In the event it is determined the
communication device is
available, step 122 of the method requires transmitting the report to the
external device by using the
communication device. The method then proceeds to step 116, of determining
whether the measured
value obtained from any sensor exceeds the threshold value pre-determined for
that particular sensor.
In the event it is determined, at step 120, that the communication device is
not available for
transmitting report to the external device, the method returns to step 116 of
determining whether the
measured value from any sensor exceeds the pre-determined threshold value. In
some embodiments of
the present disclosure, where the communication device is temporarily
unavailable for transmitting a
particular report, the report may be retrieved from the memory storage device
at a future point in time
of the pump's operation when the method returns to step 120 and the
communication device is
determined to be available. In yet other embodiments, reports stored on the
memory device may also
be retrieved at a future time when the pump is retrieved from the process
fluid and the memory device
may be physically accessed.
The water content parameter measured within the oil reservoir, motor housing
and/or the
pump bearing is particularly important to determining whether electric
submersible pump 10 requires
service, because many pump failures are attributed to either a loss of oil
from the motor and/or the
pump bearing into the surrounding process fluid, and/or ingress of the process
fluid which contains
water and other fluids, into the oil of the motor and/or pump bearing.
Examples of sensors capable of
determining the water content in the oil of either the motor or the pump
bearing, without intending to
be limiting, include a contact sensor which operates by measuring the
electrical resistance between two
electrodes located within oil being measured. Because oil does not conduct
electricity while water does
conduct electricity, the contact sensor works by measuring changes to the
electrical resistance of the
fluid measured between the two electrodes of the sensor. For example, if there
is no water content in
the oil, the electrical resistance will be a high value because oil is not an
electrical conductor. However,
in the event that the water content begins to increase, provided that there is
sufficient agitation of the
oil in the vicinity of the contact sensor such that the oil and water are
sufficiently mixed to provide a
substantially homogenous sample of the fluid being measured between the two
sensor electrodes, an
increase in the electrical conductivity between the two electrodes will be
measured due to the increase
in the water content. The sufficient agitation may be provided, for example,
by the oil circulating
system and/or the rotating shaft through the oil reservoir 30 within the pump
10. Thus, empirical data
for correlating various water contents and the resistance measured between the
sensor's electrodes
CA 02952501 2016-12-22
may be collected so as to calibrate the sensor for correlating a measured
resistance between the two
electrodes and a measured water content in the oil. A person skilled in the
art will appreciate that the
scope of this disclosure is not intended to be limited to using contact
sensors for measuring water
content and that any other type of sensor for measuring or detecting the
presence or absence of water
in various areas of the pump or outside the pump may also be deployed and are
intended to come
within the scope of this disclosure. For example, with respect to water
content sensors, it is possible
that an optical sensor may be utilized rather than a contact sensor so as to
measure, by spectroscopic
methods, the specific wavelengths of light passing through the agitated fluid
containing a mixture of oil
and a contaminant within the pump housing, so as to quantify the amount of
contaminant within oil due
to certain wavelengths of light being absorbed by the contaminants in the
mixture.
In addition to monitoring the water content parameter in areas of the
hermetically sealed
electrical submersible pump, such as for example the oil reservoir, motor
housing or the bearing
housing, other parameters of the electrical submersible pump may also be
monitored so as to
determine the status of the pump, and/or to collect data on those parameters
which may assist with
diagnosing pump failures for repair or maintenance of the pump.
For example, not intended to be limiting, one or more thermometers or devices
for measuring
temperature, which may include for example resistive temperature detectors,
may be deployed within
the various areas of the pump so as to for example detect an increase in
temperature within the
bearing, which may indicate the bearing has insufficient lubrication or
excessive wear and may be at risk
of failure, or an increase in temperature of the motor, which may indicate
that the motor has
insufficient cooling and may be at risk of a thermal overloading condition
that may lead to failure of the
motor. As another example, the magnitude of electrical current drawn by the
motor during the pump's
operation may be measured and recorded, which data may assist in predicting
pump failure, or in
diagnosing the problem with the pump after it has failed, and what may have
caused the pump to fail.
As a further example, not intended to be limiting, an oil level sensor may be
deployed in one or more
areas of the electric submersible pump, such as within the motor housing or
the bearing housing, so as
to monitor the oil levels and detect when the oil level has dropped below a
threshold level, again
indicating, for example, that an oil leakage is occurring within the pump.
Various other types of sensors may be used to monitor various parameters of
the motor,
including and not limited to for example vibration sensors, tachometers, and
any other sensors that are
known or will be known to a person skilled in the art for measuring various
operating parameters of an
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electric submersible pump, and it will be appreciated by a person skilled in
the art that the sensors
described above are provided as examples only and are not intended to be
limiting.
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