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 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. 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. Brief Description of the Figures

FIG. 1 is a front elevation view of an embodiment of visual indicators mounted to the motor section of an electric submersible pump in accordance with the present disclosure.

FIG. 2 is a logic flow diagram, showing a process for monitoring the status of an electric submersible pump in accordance with 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 the present disclosure.

FIG. 4 is a perspective view of an embodiment of visual indicators mounted to an electric submersible pump in accordance with the present disclosure.

Detailed Description

In Figure 1, an embodiment of the motor section 10 of an electric submersible pump 1 is shown. The electric submersible pump 1 includes a power cable 12 connected to the lead cover 20. The electric submersible pump 1 further includes a motor housing 16 and an oil reservoir 30. In some embodiments of the present disclosure, such as illustrated in Figure 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 embodiments, the oil reservoir of the motor section 10 may not include transparent or translucent windows, as shown in the embodiment of Figure 4. Figure 4 is an example of the HNS-Series electric submersible pumps distributed by Toyo Pumps North America™, also trading under the name Hevvy Pumps™, the HNS-Series pumps being described for example in brochures available at the website address hewypumps.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; however, the examples of electric submersible pumps described herein are not intended to be limiting, and it will be appreciated by a person ordinarily skilled in the art that the monitoring system described in the present disclosure may be deployed on other electronic submersible pumps or systems.

In some embodiments of the present disclosure, the visual indicator may include a visual display, such as for example a light display repeater bead 14, may be mounted to the power cable 12 or some other location remote from the submersible pump 1. In addition to, or as an alternative to, the light display bead 14 mounted to the power cable 12, one or more visual indicators mounted to the electric submersible pump 1 may include one or more light display strips or patches 34a, 34b and 34c. In some embodiments, the light display strips or patches 34a, 34b, 34c 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, 34c 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 or patches (also referred to herein as light indicators or visual indicators) 34a, 34b, 34c may, for example, be positioned on the upper and lower portions of the oil reservoir 30 and on the upper surface of the lead cover 20, such as the positions in which light indicators 34a, 34b, 34c are illustrated in Figures 1 and 4. The illustration of three light indicators 34a, 34b, 34c in Figure 1 or four light indicators 34a through 34d, in Figure 4, is not intended to be limiting, as any combination of any of the light indicators 34a through 34d may be mounted on the exterior of the oil reservoir 30 or lead cover 20, or in other embodiments, more than four light indicator strips or patches may be used. Advantageously, as the electric submersible pump 1 is generally oriented in direction A when submerged in a liquid or slurry, positioning one or more light indicators 34c on the uppermost surface of the pump 1, such as on the exterior surface of lead cover 20, may position such light indicators 34c to be viewed by a person observing the submerged pump 1 from above the surface of the liquid or slurry in which the pump is submerged. This description of positioning one or more light indicators 34 on an electric submersible pump is not intended to be limiting, and it will be appreciated that other positions on the exterior surface of the electric submersible pump for mounting the one or more light display strips 34 are within the scope of the present disclosure.

For embodiments of the electric submersible pump incorporating a translucent or transparent portion of the oil reservoir 30, such as illustrated in Figure 1, the one or more light indicators 34a _; 34b 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, as light from the light indicators 34a, 34b may be transmitted, for example, through the transparent or translucent windows 32 of the oil reservoir 30. Advantageously, mounting the light display strips 34 within the interior of the translucent or transparent oil reservoir 30 reduces the number of cables that run 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 1 is immersed. More than one bead 14, or other corresponding light display (collectively referred to herein as light indicator(s)), 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, or in other embodiments, the repeater bead or other light display (also referred to herein as light indicators) may be attached to a fixed junction box at the end of the power cable opposite the pump.

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 Figure 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 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.

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 Figure 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 Figure 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 Figure 2, and an additional step occurring after the report generated by the controller has been written to memory, at step 114 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 1 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 motor section 10. Thus, empirical data for correlating various water contents and the resistance measured between the sensor's electrodes 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 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.