Abstract: A floating roof monitoring system and method. One or more sensors can be disposed atop a liquid storage tank having a floating roof covering liquid stored in the liquid storage tank. Each laser sensor measures the distance between the sensor and the floating roof. One or more liquid level gauges can be deployed, which measure a liquid position of the liquid stored in the liquid storage tank. A computing system communicates electronically with the laser sensor(s) and the liquid level gauge(s) to calculate the difference between the liquid position and the distance between the sensor(s) and the floating roof to determine the exact position of the floating roof and activate an alarm or force a process associated with the liquid storage tank to halt.

Abstract: A method of measuring liquid level in a tank. An electromechanical liquid level gauge (ESG) is provided including a processor, a displacer suspended on a wire from a grooved drum having a servo motor coupled thereto to rotate the drum for balancing the displacer. A change in liquid level causes a change in a counterforce to move the ESG out of balance. The processor monitors a torque sensor output, and controls movement of the motor using a programmed apparent weight (AW) setpoint to raise or lower the displacer based on an AW derived from the torque. An associated memory stores a density compensated fixed immersion depth level gauging algorithm. The algorithm implements obtaining a density reading for the liquid, continuously corrects an immersion depth of the displacer for changes in density to provide an essentially fixed immersion depth, and calculates the liquid level from the density reading and immersion depth.

Abstract: A method includes measuring tensions on a measuring wire coupled to a displacer of a servo gauge. The servo gauge is configured to raise and lower the displacer using a drum around which the measuring wire is wound. Different measured tensions are associated with different segments of the measuring wire. The method also includes calculating or adjusting a measurement associated with material in a tank using the measured tensions to account for a change in a length of the measuring wire. Calculating or adjusting the measurement could include calculating one or more first length adjustments for one or more segments of the measuring wire that are wound around the drum, calculating one or more second length adjustments for one or more other segments of the measuring wire that are unwound from the drum, and combining the first and second length adjustments to identify a final length adjustment.

Abstract: A level gauge system for mounting on a roof of a semi-closed storage tank includes an automatic tank level gauge for determining a level reading for a liquid including at least one liquid component in the tank. A processor includes a memory storing pressure correction factors or a pressure correction factor equation for correcting the level reading for a measured gas pressure above the liquid in the tank. The processor is programmed for implementing choosing a selected pressure correction factor from the pressure correction factors or the equation based on a received current gas pressure above, and applying the selected pressure correction factor for automatically correcting the level reading provided by the tank level gauge to generate a corrected level reading which compensates for the current gas pressure above effects on the roof and on the level gauge.

Abstract: A small volume prover apparatus and method for precisely measuring the displaced volume of a fluid. A precision bore cylinder and a piston can be configured with a valve arrangement in order to permit fluid to pass through an annular passage when the piston travels from one position to an opposite position. A magnetized forcer connected to the piston and a magnetic drive chamber configured to produce linear motion of said magnetized forcer are operably connected to the piston in order to move the piston from one position to the other.

Abstract: A method of process control within a plant includes providing a first and second field device associated with processing equipment sensing a first and second process parameter respectively. The field devices are communicably coupled to a host computer by a communications path including a shared field communications channel portion (shared communications channel) that terminates at a communications device which includes a processor and memory that implements an adaptive scan period determination algorithm (adaptive scanner) which determines a first scan period for the first field device and a second scan period for the second field device each based on a parameter relevant to a data type of the process parameter or communications used. The host computer monitors operations in the plant using sampled data provided by the communications device including data based on the first and second process parameter at their respective scan periods.

Abstract: A method includes measuring tensions on a measuring wire coupled to a displacer of a servo gauge. The servo gauge is configured to raise and lower the displacer using a drum around which the measuring wire is wound. Different measured tensions are associated with different segments of the measuring wire. The method also includes calculating or adjusting a measurement associated with material in a tank using the measured tensions to account for a change in a length of the measuring wire. Calculating or adjusting the measurement could include calculating one or more first length adjustments for one or more segments of the measuring wire that are wound around the drum, calculating one or more second length adjustments for one or more other segments of the measuring wire that are unwound from the drum, and combining the first and second length adjustments to identify a final length adjustment.

Abstract: A small volume prover apparatus and method for precisely measuring the displaced volume of a fluid. A precision bore cylinder and a piston can be configured with a valve arrangement in order to permit fluid to pass through an annular passage when the piston travels from one position to an opposite position. A magnetized forcer connected to the piston and a magnetic drive chamber configured to produce linear motion of said magnetized forcer are operably connected to the piston in order to move the piston from one position to the other.

Abstract: A level gauge system for mounting on a roof of a semi-closed storage tank includes an automatic tank level gauge for determining a level reading for a liquid including at least one liquid component in the tank. A processor includes a memory storing pressure correction factors or a pressure correction factor equation for correcting the level reading for a measured gas pressure above the liquid in the tank. The processor is programmed for implementing choosing a selected pressure correction factor from the pressure correction factors or the equation based on a received current gas pressure above, and applying the selected pressure correction factor for automatically correcting the level reading provided by the tank level gauge to generate a corrected level reading which compensates for the current gas pressure above effects on the roof and on the level gauge.

Abstract: A method of storage tank monitoring including calculating liquid inventory within the storage tank. Real-time parameters associated with evaporative loss of a liquid stored within the storage tank are determined to produce input data. The real-time parameters include at least one condition within the storage tank and at least one environmental condition. Evaporative loss is automatically calculated with an inventory calculation algorithm using the input data and at least one known physical property of the liquid in the storage tank.

Abstract: A method of measuring liquid level in a tank. An electromechanical liquid level gauge (ESG) is provided including a processor, a displacer suspended on a wire from a grooved drum having a servo motor coupled thereto to rotate the drum for balancing the displacer. A change in liquid level causes a change in a counterforce to move the ESG out of balance. The processor monitors a torque sensor output, and controls movement of the motor using a programmed apparent weight (AW) setpoint to raise or lower the displacer based on an AW derived from the torque. An associated memory stores a density compensated fixed immersion depth level gauging algorithm. The algorithm implements obtaining a density reading for the liquid, continuously corrects an immersion depth of the displacer for changes in density to provide an essentially fixed immersion depth, and calculates the liquid level from the density reading and immersion depth.

Abstract: A method of process control within a plant includes providing a first and second field device associated with processing equipment sensing a first and second process parameter respectively. The field devices are communicably coupled to a host computer by a communications path including a shared field communications channel portion (shared communications channel) that terminates at a communications device which includes a processor and memory that implements an adaptive scan period determination algorithm (adaptive scanner) which determines a first scan period for the first field device and a second scan period for the second field device each based on a parameter relevant to a data type of the process parameter or communications used. The host computer monitors operations in the plant using sampled data provided by the communications device including data based on the first and second process parameter at their respective scan periods.

Abstract: A floating roof monitoring system and method. One or more sensors can be disposed atop a liquid storage tank having a floating roof covering liquid stored in the liquid storage tank. Each laser sensor measures the distance between the sensor and the floating roof. One or more liquid level gauges can be deployed, which measure a liquid position of the liquid stored in the liquid storage tank. A computing system communicates electronically with the laser sensor(s) and the liquid level gauge(s) to calculate the difference between the liquid position and the distance between the sensor(s) and the floating roof to determine the exact position of the floating roof and activate an alarm or force a process associated with the liquid storage tank to halt.

Abstract: A small volume prover (SVP) apparatus and method for providing variable volume calibration. The apparatus includes a precision bore cylinder and a piston configured with a valve arrangement in order to permit fluid to pass through an annular passage when the piston is traveling from one position to an opposite position. A position sensor and a pair of optical slot detectors can be integrated in association with the piston for continuously sensing an accurate position and stroke of the piston. The position sensor verifies the optical slot detectors at every run and provides calibration of flexible volumes as the fluid travels via the annular passage. The position sensor also checks the correct return of the piston after the flow stroke and detects the stuck mechanics. Such small volume prover apparatus associated with the position sensor can be employed for precise and fast position sensing of the piston and variable volume calibration of a fluid flow sensor.

Abstract: A method of storage tank monitoring including calculating liquid inventory within the storage tank. Real-time parameters associated with evaporative loss of a liquid stored within the storage tank are determined to produce input data. The real-time parameters include at least one condition within the storage tank and at least one environmental condition. Evaporative loss is automatically calculated with an inventory calculation algorithm using the input data and at least one known physical property of the liquid in the storage tank.

Abstract: An apparatus includes a servo gauge. The servo gauge includes a displacer configured to be raised and lowered within material in a tank. The servo gauge also includes at least one light source configured to illuminate a sample of the material at the displacer. The servo gauge further includes at least one detector configured to measure radiation that has interacted with the sample of the material at the displacer. In addition, the servo gauge includes an analyzer configured to perform Raman spectroscopy analysis of measurements from the at least one detector and identify at least one characteristic of the material.

Abstract: An apparatus includes a first valve configured to selectively direct material to first and second outlets and a second valve configured to block the second outlet. The first and second valves define a dead space that has a volume between the first and second valves. The apparatus also includes a pressure compensation unit configured to dynamically provide an additional volume for material trapped in the dead space when the trapped material expands. The pressure compensation unit could include a piston configured to move within a space of the pressure compensation unit, where increased pressure in the dead space causes the trapped material to push against the piston in order to provide the additional volume for the trapped material. The pressure compensation unit could further include a spring configured to bias the piston and a seal configured to substantially prevent the trapped material from passing the piston and contacting the spring.

Abstract: A small volume prover (SVP) apparatus and method for providing variable volume calibration. The apparatus includes a precision bore cylinder and a piston configured with a valve arrangement in order to permit fluid to pass through an annular passage when the piston is traveling from one position to an opposite position. A position sensor and a pair of optical slot detectors can be integrated in association with the piston for continuously sensing an accurate position and stroke of the piston. The position sensor verifies the optical slot detectors at every run and provides calibration of flexible volumes as the fluid travels via the annular passage. The position sensor also checks the correct return of the piston after the flow stroke and detects the stuck mechanics. Such small volume prover apparatus associated with the position sensor can be employed for precise and fast position sensing of the piston and variable volume calibration of a fluid flow sensor.

Abstract: An apparatus includes a first valve configured to selectively direct material to first and second outlets and a second valve configured to block the second outlet. The first and second valves define a dead space that has a volume between the first and second valves. The apparatus also includes a pressure compensation unit configured to dynamically provide an additional volume for material trapped in the dead space when the trapped material expands. The pressure compensation unit could include a piston configured to move within a space of the pressure compensation unit, where increased pressure in the dead space causes the trapped material to push against the piston in order to provide the additional volume for the trapped material. The pressure compensation unit could further include a spring configured to bias the piston and a seal configured to substantially prevent the trapped material from passing the piston and contacting the spring.

Abstract: A method for displaying the quality of a digital communications link for field devices of automation technology on a field device serving as a monitoring unit. According to the method telegrams are transmitted via the communications link and are tapped in the monitoring unit and tested according to at least two criteria. The result of the testing is displayed as a bar chart on the monitoring unit, so that the user can observe quality of the communications link simply and easily.