Measuring and testing – Volume or rate of flow – Using rotating member with particular electrical output or...
Reexamination Certificate
2001-08-30
2004-05-25
Lefkowitz, Edward (Department: 2855)
Measuring and testing
Volume or rate of flow
Using rotating member with particular electrical output or...
C702S101000
Reexamination Certificate
active
06739205
ABSTRACT:
DESCRIPTION
The present invention generally relates to a method, system, and program for monitoring and controlling a fluid transportation system. More specifically, the present invention is directed to a medium readable by a programmable device. The medium being operably connected to a controller for monitoring and controlling a fluid flow volume in a fluid transportation system.
BACKGROUND OF THE INVENTION
The production, transportation and sale of energy sources has always required some form of measurement to determine the quantity produced, bought, or sold. The accuracy and reliability of a system that measures an energy source, i.e., gas and liquid, is extremely important to the buyers and sellers involved. A seemingly insignificant error within the measuring system can result in a large monetary loss.
Technological advances in the areas of fluid flow metering and computation has led to improved accuracy and reliability. Some of these advances have been made in the area of metering, or measuring, transported energy products. These advances have also focused on factors such as safety, reliability and standardization.
Today's metering and transfer system involves more than simply measuring fluid flow; it can also involve extensive electronics, software, communication interfaces, analysis, and control. Measuring fluid flow can involve multiple turbine meters with energy flow computers, densitometers, gas chromatography, meter proving systems and RTU or SCADA interfaces.
Measurement and control of energy sources are valuable processes for companies producing and transporting theses energy sources. Many governments, organizations and industries have enacted standards and regulations related to recovering, refining, distributing, and selling of oil and oil by-products, i.e., gasoline, kerosene, butane, ethanol, etc. The energy resource industry has various standards and regulations to ensure the accuracy and safety of transporting and metering these energy sources.
The process of transporting a fluid energy source, e.g., oil, through a pipeline is monitored and controlled with the assistance of a combination of sensors and process computers. Generally, a computer processor monitors several aspects, e.g., fluid flow volume, of the oil transportation. The control of the equipment facilitating the transportation of oil is generally performed by environmentally robust devices such as a controller. The controller regulates valves, tanks, and scales without requiring an individual to constantly interact with the system.
A very important aspect of a fluid transportation system involves the fluid flow meter utilized to monitor the amount of oil delivered to a customer. Because of the vast amounts of fluid delivered, the accuracy of the fluid flow meter must be ensured at regular intervals. An inaccurate fluid flow meter can result in overcharging or undercharging a customer for the delivered product. An inaccurate flow metering system can result in significant amounts of unpaid products, i.e., shrinkage.
A turbine flow meter is an accurate and reliable flow meter for both liquid and gas volumetric flow. Some applications utilizing a turbine flow meter involve water, natural gas, oil, petrochemicals, beverages, aerospace, and medical supplies. The turbine comprises a rotor having a plurality of blades mounted across the flow direction of the fluid. The diameter of the rotor is slightly less than the inner diameter of a conduit, and its speed of rotation is proportional to the volumetric flow volume through the conduit. Turbine rotation can be detected by solid state devices or mechanical sensors.
In one application utilizing a variable reluctance coil pick-up, i.e., a permanent magnet, turbine blades are made of a material attracted to the magnet. As each blade of the turbine passes the coil, a voltage pulse is generated in the coil. Each pulse represents a discrete volume of liquid. The number of pulses per unit volume is called the meter's K-factor.
In another application utilizing inductance pick-up, a permanent magnet is embedded in the rotor. As each blade passes the coil, a voltage pulse is generated. Alternatively, only one blade is magnetic and the pulse represents a complete revolution of the rotor. Depending upon the design, it may be preferable to amplify the output signal prior to its transmission.
The accuracy of a turbine flow meter partially depends upon proving the fluid flow meter and the ability to provide correction factors to compensate for meter inaccuracies caused by damage to the meter or surrounding environmental conditions. At a minimum, a typical flow computer utilizes the following industrial standard volume flow equations to determine the correction factors. The American Petroleum Institute defines the API 2540 standard to determine flow of liquid hydrocarbons that includes the following techniques: meter proving; correction for temperature, density (fluid gravity) and pressure of the fluid flowing; pulse interpolation; pulse fidelity; correction for the temperature and pressure of the conduit material (typically steel); and audit trails and report specifications. The American Society for Testing & Materials that defines the ASTM D1250 and the American National Standards Institute that defines the ANSI D1250 standard have adopted, in their respective industry segments, the API 2540 standards. The American Petroleum Institute also defines a M factor used to correct for the loss of turbine accuracy. Over time, the turbine becomes less accurate due to wear and tear; and the M factor—a dimensionless number—incorporated into the API 2540 equations adjusts for turbine inaccuracy. API 2540, ASTM D1250 and ANSI D1250 are expressly incorporated herein by reference.
Proving the fluid flow meter is a process for ensuring the accuracy and reliability of the flow meter. Typically, a section of the fluid system called a proving loop is utilized during the meter proving. The dimensions of the proving loop are known and the flow of fluid within the loop can be monitored by sensors wherein a variety of fluid characteristics can be sensed. The meter proving process simultaneously monitors a pulse signal generated by a turbine operably connected within the fluid system. The flow volume of the fluid is determined by utilizing the sensed values of the fluid's characteristics with the industrial standard flow volume equations. The calculated flow volume is then compared to the known flow volume of the proving loop. By comparing the calculated fluid flow volume to the known fluid flow volume of the proving loop, the accuracy of the flow meter can be determined.
Generally, the duration of a meter proving process is approximately one hundred thousand turbine pulses. This amount of time is believed to be adequate to accurately determine the fluid flow volume. Often times, the turbine pulse signal is not in synch with the flow meter proving process, i.e., generally the meter proving process will not start at the beginning of the turbine pulse signal. When the pulses are counted at the end of the proving period, the partial pulses occurring at the beginning and end of the proving period are omitted. Because of the duration of the proving period, it is generally believed that these partial pulses are negligible. However, utilizing the partial pulses and other characteristics of the fluid and conduit, the time required for the meter proving process can be reduced.
This invention is directed to solving these and other problems.
SUMMARY OF THE INVENTION
The present invention is directed to utilizing a software program operable within a controller to monitor a flow volume in a fluid transportation system. The software interacts with the controller, e.g., programmable logic controller (PLC), and an operably connected flow meter to sense a characteristic of the fluid for calculating the fluid flow volume of the liquid. The sensed characteristic of the fluid, e.g., temperature, density, and pressure; is utilized by the software program to determine correction factors to be incor
Golden Larry I.
Lefkowitz Edward
Mack Corey D.
Schneider Automation Inc.
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