Apparatus and method for product movement planning to support safety monitoring in inventory management systems

A method includes obtaining information identifying a predicted trajectory of material-based measurements associated with a transfer of material. The method also includes obtaining actual material-based measurements during the transfer of the material and determining whether the actual material-based measurements fall outside of the predicted trajectory. The method further includes identifying a problem with the transfer of the material if at least one of the actual material-based measurements falls outside of the predicted trajectory. The method may also include generating the predicted trajectory of the material-based measurements using historical data associated with one or more prior transfers, such as historical data associated with at least one pump to be used during the transfer of the material. The actual material-based measurements could include measurements of a level and/or a volume of the material in a tank.

TECHNICAL FIELD

This disclosure relates generally to inventory management systems. More specifically, this disclosure relates to an apparatus and method for product movement planning to support safety monitoring in inventory management systems.

BACKGROUND

Various facilities routinely include tanks for storing liquid materials and other materials. For example, storage tanks are routinely used in tank farms and other storage facilities to store oil or other materials. As another example, oil tankers and other liquid transport vessels routinely include numerous tanks storing oil or other materials.

Often times, it is necessary or desirable to measure the level of material in a tank, such as during loading of material into the tank or unloading of material from the tank. Among other approaches, radar gauges and servo gauges have been used to measure the material level in a tank. A radar gauge typically transmits radar signals towards material in a tank and receives radar signals reflected off the surface of the material in the tank. A servo gauge typically raises and lowers a displacer located inside a tank, where the displacer's weight changes when submerged in the material.

On occasion, radar gauges, servo gauges, and other level-measuring gauges stop functioning properly. For example, the displacer of a servo gauge could become stuck within a tank. Similarly, pumps or other equipment could malfunction during the transfer of material into or out of a tank. These and other problems could allow volatile or other dangerous material to escape, resulting in environmental damage and injury or even death to nearby personnel. As a result, level-measuring gauges, pumps, and other equipment often include circuitry or other components for periodically testing the equipment or otherwise ensuring that the equipment is operating properly.

SUMMARY

This disclosure provides an apparatus and method for product movement planning to support safety monitoring in inventory management systems.

In a first embodiment, a method includes obtaining information identifying a predicted trajectory of material-based measurements associated with a transfer of material. The method also includes obtaining actual material-based measurements during the transfer of the material. The method further includes determining whether the actual material-based measurements fall outside of the predicted trajectory. In addition, the method includes identifying a problem with the transfer of the material if at least one of the actual material-based measurements falls outside of the predicted trajectory

In a second embodiment, an apparatus includes a processing unit configured to obtain information identifying a predicted trajectory of material-based measurements associated with a transfer of material. The apparatus also includes an interface configured to obtain actual material-based measurements during the transfer of the material. The processing unit is further configured to determine whether the actual material-based measurements fall outside of the predicted trajectory and to identify a problem with the transfer of the material if at least one of the actual material-based measurements falls outside of the predicted trajectory.

In a third embodiment, a computer readable medium embodies a computer program. The computer program includes computer readable program code for obtaining information identifying a predicted trajectory of material-based measurements associated with a transfer of material. The computer program includes also computer readable program code for obtaining actual material-based measurements during the transfer of the material. The computer program further includes computer readable program code for determining whether the actual material-based measurements fall outside of the predicted trajectory. In addition, the computer program includes computer readable program code for identifying a problem with the transfer of the material if at least one of the actual material-based measurements falls outside of the predicted trajectory.

DETAILED DESCRIPTION

FIG. 1illustrates an example inventory management system100using product movement planning to support safety monitoring according to this disclosure. As shown inFIG. 1, the system100includes at least one tank102that can store one or more materials104. The tank102represents any suitable structure for receiving and storing at least one liquid or other material104. The tank102could, for example, represent an oil storage tank or a tank for storing other liquid(s) or other material(s). The tank102could also have any suitable shape and size. Further, the tank102could form part of a larger structure. The larger structure could represent any fixed or movable structure containing or associated with one or more tanks102, such as a movable tanker vessel, railcar, or truck or a fixed tank farm.

In this example, the tank102includes at least one hatch106, such as a maintenance hatch. The hatch106could, for example, represent a door or other opening that can be opened to provide access to the interior of the tank102. The hatch106could then be closed and sealed to prevent material104from leaking or otherwise escaping the tank102through the hatch106.

The material104flows into and out of the tank102through one or more transfer pipes108. The flow of material104through the transfer pipe(s)108is controlled using one or more pumps110and one or more valves112. The pump110can pump the material104from an external source into the tank102through the transfer pipe108and the valve112. The pump110can also pump the material104out of the tank102through the valve112and the transfer pipe108to an external destination. The valve112can be opened and closed to control the flow of the material104through the transfer pipe108.

The pump110is associated with a pump actuator114, which controls the operation of the pump110in order to adjust the pumping of material104into or out of the tank102. Similarly, the valve112is associated with a valve actuator116, which opens and closes the valve112to adjust the flow of material through the transfer pipe108.

The transfer pipe108includes any suitable tube or similar structure for transporting material between locations. The pump110includes any suitable structure for pumping moving material. The valve112includes any suitable structure for controlling a flow of material. The pump actuator114includes any suitable structure for controlling the operation of at least one pump. The valve actuator116includes any suitable structure for opening and closing at least one valve.

At least one controller118controls the operation of the pump actuator114and the valve actuator116, thereby controlling the pump110and the valve112. The controller118could, for example, receive commands from a site operator to begin loading or unloading the material104in the tank102, as well as commands such as setting the loading or unloading rate or other characteristics of the transfer. The controller118includes any suitable structure for controlling equipment for loading or unloading a tank.

A level sensor120measures the level of material104in the tank102. The level sensor120can use any suitable technique to measure the level of material104in the tank102. For example, the level sensor120could represent a non-contact sensor, such as a radar gauge or other gauge that operates using wireless signals. The level sensor120could also represent a contact sensor, such as a servo gauge or other gauge that physically contacts the material104. The level sensor120includes any suitable structure for measuring the level of material in a tank.

Due to the natural of the material104to be stored in the tank102(such as flammable, explosive, or toxic material), safety is very important in the system100. During operations, many things can go wrong: the tank102could leak, the transfer pipe108could leak, the hatch106could be left open, the pump110or valve112could malfunction, or the level sensor120could get stuck or otherwise fail. The early detection of these or other kind of events can be very important to protect against business or environmental damage and personal injury or death. Many techniques for identifying problems focus on establishing that equipment used during the transfer of material (like the level sensor120) is operating correctly. In other words, these techniques attempt to prove the health status of the equipment.

In accordance with this disclosure, problems in the system100are detected using a site operator's transfer plan. Before the material104is moved into or out of the tank102, the site operator defines a transfer plan, which identifies the expected or predicted movement of the material104into or out of the tank102. The transfer plan could, for example, identify when the transfer of material104is to begin, the flow (pump capacity) to be used, and how much material104is to be transferred. The transfer plan therefore predicts the amount or level of material104in the tank102during the transfer. Effectively, the transfer plan identifies the expected path or trajectory of the material level in the tank102as measured by the level sensor120.

When the transfer actually occurs, the system100monitors the measured level of material104in the tank102and verifies whether the measured material level matches the predicted material level. A leaking tank102or pipe108, a malfunctioning pump110or valve112, an open hatch106, a failed level sensor120, or other problem could cause the measured level of material104to deviate from the predicted trajectory, triggering an alarm or other corrective action. This approach therefore uses the operator's transfer plan as a reference for safety checks and does not depend on all sorts of instrument checks to verify that various equipment is operating properly.

To support this functionality, a monitoring system122receives the level measurements from the level sensor120. The monitoring system122also receives information defining the transfer plan or other information identifying the expected level of material104in the tank102during a transfer. The monitoring system122can compare the actual level of material104in the tank102against the predicted level and take corrective action if the actual level differs from the predicted level by a threshold amount (such as by a threshold percentage or level difference). The corrective action could include presenting an alarm message on a display screen124, transmitting a warning message to a user's wireless device126, triggering an audible warning signal, or generating some other suitable indicator. The threshold amount that triggers the corrective action could be customizable.

In some embodiments, the creation of the transfer plan or the predicted level's trajectory may be based on historical data, such as data collected by a historian128. The historical data could, for example, represent data identifying the rate at which material104flows through the transfer pipe108at different settings of the pump110. As a particular example, the historical data could include level measurements taken during loading or unloading of the tank102at different settings of the pump110and valve112. The historical data could also represent information identifying the pumping capacity of the pump110. A statistical module or other logic implemented or used by the monitoring system122could predict product movement trends (trajectories) based on the characteristics of previous transfers stored in the historian128. The historian128includes any suitable structure for storing historical data associated with the system100, such as a database.

In this way, the monitoring system122can monitor the actual level of material104in the tank102and compare the actual level to an expected trajectory. While some variation of the actual level from the predicted trajectory may be expected, any excessive variation could be indicative of some problem in the system100that is affecting the material level. This allows the monitoring system122to identify problems in the system100without requiring each individual piece of equipment to undergo testing or performance monitoring (although they could).

The monitoring system122could represent any suitable computing or processing system or device, such as a computing device, a process controller, or other system or device. In particular embodiments, the monitoring system122includes at least one processing unit130, such as a microprocessor, microcontroller, digital signal processor, field programmable gate array, or application-specific integrated circuit. The monitoring system122can also include at least one memory132storing instructions and data used, generated, or collected by the processing unit(s)130and at least one network interface134facilitating communication with external devices or systems, such as the components118-120,124-128. The interface134could include an Ethernet interface, a radio frequency (RF) transceiver, or other wired or wireless interface. As a particular example, the functionality of the monitoring system122could be implemented in one or more software modules, which could be installed on new or existing systems.

AlthoughFIG. 1illustrates one example of an inventory management system100using product movement planning to support safety monitoring, various changes may be made toFIG. 1. For example, a system could include any number of tanks, hatches, pipes, pumps, valves, actuators, sensors, monitoring systems, and other components. Also, the makeup and arrangement of the inventory management system100are for illustration only. Components could be added, omitted, combined, subdivided, or placed in any other suitable configuration according to particular needs. As a particular example, the monitoring system122could implement the functionality of the process controller118. In addition,FIG. 1illustrates one operational environment in which product movement planning to support safety monitoring can be used. This functionality could be used in any other suitable device or system.

FIG. 2illustrates example product movement planning to support safety monitoring according to this disclosure. InFIG. 2, a graph200plots a material level in a tank102over time. An example trajectory202is shown as a hatched area inFIG. 2. The trajectory202identifies the predicted path of the material level in the tank102during loading of the tank102. The trajectory202defines a range of levels vertically for each instance in time, where upper and lower margins of the trajectory202are defined by lines204-206on top and bottom of the hatched area. As long as the actual material level stays within this range, the monitoring system122may view the material level as being acceptable. If the actual material level exits this range, the monitoring system122may view the material level as being indicative of a problem and take corrective action.

In this example, line208represents the actual level of the material104in the tank102, and line210represents the level measurements taken by the level sensor120. As can be seen here, the line208remains within the trajectory202, which indicates that the trajectory202accurately predicts the material level. The line210remains within the trajectory202until an obstruction is reached, such as where a displacer of the level sensor120gets stuck on an obstruction within the tank102. When that occurs, the line210becomes generally flat, indicating that the level measurements have become relatively constant at a fixed level. This occurs even though the line208continues to increase, meaning the actual level of material104in the tank102continues to rise. When the line210leaves the hatched area representing the trajectory202, this means the actual level measurements differ from the predicted measurements by more than a threshold amount, and an alarm can be triggered or other corrective action can be taken.

Note that the reason the actual level measurements differ from the predicted measurements need not be identified here. Rather, the monitoring system122can determine that some type of problem exists with the transfer of material104, regardless of whether the problem is a leaking tank or pipe, a stuck servo displacer, a malfunctioning pump, or other problem. The monitoring system122can notify the appropriate personnel of the problem, allowing the personnel to take steps to identify and resolve the problem. Optionally, the monitoring system122could include logic for assisting in the identification of the faulty system component(s).

As shown inFIG. 2, the area or difference between the margins for the trajectory202has a direct relationship with the amount of time it takes to identify an anomaly. In this example, the time between (i) the displacer getting stuck at the obstruction level and (ii) the line210exiting the hatched area is denoted T1. Smaller areas or differences between the margins for the trajectory202would result in smaller times T1, while larger areas or differences between the margins for the trajectory202would result in larger times T1. When a problem occurs, the length of time between identification of the problem and an accident (such as overflow) is denoted T2. The total time between occurrence of the problem and an accident is denoted T3. Ideally, the size of the area or difference between the margins can be set by an operator so that the time T1is long enough to avoid most or all false alarms while still providing adequate time T2to avoid accidents.

In some embodiments, the graph200can be presented to an operator as part of a graphical user interface. The operator could use controls on the graphical user interface to create a time/level plot defining a trajectory202to be used during a later material transfer. Controls could also be used to access historical data and invoke statistical functions in order to generate an estimated trajectory202of the material level. Once the transfer actually starts, the graphical user interface could display the line210over the trajectory202, allowing the operator to monitor the progress of the transfer and to see if the actual level measurements are staying within the margins of the trajectory202.

In addition, the monitoring system122could generate a “score” or other value indicating how well an operator created a trajectory202. The score could be calculated based on how well the trajectory202tracked the actual level measurements, as well as the difference between the upper and lower margins of the trajectory202(since it is easier to create a trajectory202with margins that are farther apart). The score could be used in any suitable manner. For example, the scores could be used to identify whether a particular operator requires additional training or to identify better performing operators.

AlthoughFIG. 2illustrates one example of product movement planning to support safety monitoring, various changes may be made toFIG. 2. For example, the trajectory202, lines204-210, and times T1-T3inFIG. 2are for illustration only. Any other trajectory202having user-defined or other margins could be used, and the margins need not be constant. Also, the actual material level and level measurements vary depending on the circumstances. Further, the times T1-T3vary depending on the circumstances, such as when the time T3is larger or smaller depending on when the interruption to the level measurements occurs. In addition, there may be problems other than obstructions that interrupt measurements of the material level in the tank102.

FIG. 3illustrates an example method300for using product movement planning to support safety monitoring according to this disclosure. As shown inFIG. 3, information identifying a predicted trajectory of a material level in a tank during a transfer is obtained at step302. This could include, for example, the monitoring system122receiving information defining the trajectory202from an operator using a graphical user interface. This could also include the monitoring system122or the operator using historical data from the historian128to generate the trajectory202by predicting the level of material104in the tank102during an upcoming transfer. The transfer of material is initiated at step304, and material is loaded into or unloaded from a tank at step306. This could include, for example, the controller118causing the pump110to pump material104into or out of the tank102through the valve112.

One or more level measurements of the material in the tank are obtained at step308. This could include, for example, the monitoring system122receiving the level measurements from the level sensor120. The level measurements could be continuous, near-continuous, or intermittent (such as at a specified interval). The level measurements are compared against the trajectory at step310. This could include, for example, the monitoring system122comparing the level measurements received from the level sensor120against the range of values defined by the margins of the trajectory202.

A determination is made whether the level measurements are within the trajectory at step312. This could include, for example, the monitoring system122determining whether one or more level measurements from the level sensor120fall outside the range of values defined by the margins of the trajectory202. The number of level measurements required to fall outside the trajectory202before identifying a problem could be fixed or configurable by an operator. The monitoring system122could determine that a single level measurement outside the trajectory202is excessive, or the monitoring system122could require that multiple level measurements fall outside the trajectory202before determining that a problem exists.

If the level measurements are within the trajectory, the process returns to step306to continue the transfer of material into or out of the tank.

Otherwise, if the level measurements are outside the trajectory, corrective action is taken at step314. This could include, for example, the monitoring system122sounding an audible alarm, displaying a warning message, or causing the controller118to shut down the pump110or close the valve112. Any other or additional action(s) could be taken by the monitoring system100.

AlthoughFIG. 3illustrates one example of a method300for using product movement planning to support safety monitoring, various changes may be made toFIG. 3. For example, while shown as a series of steps, various steps inFIG. 3could overlap, occur in parallel, occur in a different order, or occur multiple times.

It may be noted that while the above description has described the use of level measurements from the level sensor120to identify a problem, other measurements could also be used. For example, the monitoring system122could operate using volume measurements received from a volume sensor, where the volume measurements identify the volume of material104in the tank102. The monitoring system122could also use a trajectory of predicted volume measurements and compare the actual volume measurements against the trajectory to identify a problem. In general, the monitoring system122could use any “material-based measurements” in order to identify a problem, where the material-based measurements represent any measurements based on the amount of material104in a tank102.