Flow computer
Encyclopedia
A flow computer is an electronic computational device which implements the required algorithms to turn the raw data received from flow meters to which it is connected into volumes at base conditions
.
A flow computer also audits changes that have been made to any of the parameters required to turn the raw flow meter data into volumes. It records events and alarms related to the flow meter (for example, loss of flow, loss of required electrical signals from measurement transducers, or transition of these electrical signals near their upper or lower range). It will keep a running tally of the volume for each flow meter it monitors and perform a gauge off of this volume on an hourly, daily or monthly basis. The flow data is made available externally through an electronic interface so that other computers can download the information for the purposes of supervision, accounting or auditing.
Many types of flow meter equipment implement flow computers intrinsically. Many different types of RTUs that can be used as flow computers are available, most notably from Fisher/Rosemount, Totalflow, Bristol-Babcock, Emerson, Yokagawa, Control Microsystems, Omni, Eagle Research Corp. and Flow-X series(Spirit-IT),.
Algorithms one can expect to see implemented in a typical gas flow computer are AGA Report No. 3, AGA Report No. 7, AGA Report No. 8. Additional to natural gas, some flow computers offer an array of density calculations for steam, oxygen, hydrogen, nitrogen, and ethylene. Complex algorithms and Equations of State for wide ranges of hydrocarbon fluids and petrochemicals can also be found in liquid flow computers. API MPMS Chapter 11.1 (2004), NIST 1045 and IUPAC for ethylene
measurement, GPA TP-27 for LPGs and NGLs are amongst an array of calculations performed by liquid flow computers. Other corrections specific to particular types or manufacturers of flow meters may also be implemented. Flow computers can include meter viscosity linearization functions for various meter types such as helical turbine meters, and interface serially with ultrasonic meters to obtain flow and diagnostic data.
Flow computers are available as completely programmable devices or as configurable devices using manufacturer's specific configuration software packages to setup interfaces to gas chromatographs, gas ultrasonic meters, liquid provers, flow control valve
s, PLC
, DCS
, SCADA
and industry-recognized HMI supervisory systems. Higher-level flow computers are also supported by OLE for process control
drivers such as MatrikonOPC, KEPware and Autosol to create efficient data transfers on networks. Modbus
/TCP is a standard offering via Ethernet
interfaces from some flow computers. Security issues are very significant in SCADA system development using flow computers. Recognized industry leaders in specialty flow computers are companies such as Eagle Research Corp., OMNI
and Emerson
. The new generation flowcomputers of Krohne Oil and Gas has even more capabilities, like VGA touchscreen with supervisory like screen to operate valves and flow settings. Even a web Server onboard to access the reports and supervisory like displays.
And this trough a simple web browser.
A key component in custody transfer systems, flow computers can be approved to meterological and quality standards such as OIML R117-1 for liquids, EN12405 for gas, WELMEC 7.2 for software development, and ISO 9001:2008. These are considered key selection criteria for flow computers that are installed in Europe
, Middle East
and Asia
.
Base conditions
Base conditions consist of a specified absolute pressure and temperature. To ensure accuracy, it is important to refer to base conditions when measuring the volume of a sample of liquid or gas. This applies to both static measurement and flow measurement....
.
A flow computer also audits changes that have been made to any of the parameters required to turn the raw flow meter data into volumes. It records events and alarms related to the flow meter (for example, loss of flow, loss of required electrical signals from measurement transducers, or transition of these electrical signals near their upper or lower range). It will keep a running tally of the volume for each flow meter it monitors and perform a gauge off of this volume on an hourly, daily or monthly basis. The flow data is made available externally through an electronic interface so that other computers can download the information for the purposes of supervision, accounting or auditing.
Many types of flow meter equipment implement flow computers intrinsically. Many different types of RTUs that can be used as flow computers are available, most notably from Fisher/Rosemount, Totalflow, Bristol-Babcock, Emerson, Yokagawa, Control Microsystems, Omni, Eagle Research Corp. and Flow-X series(Spirit-IT),.
See also
API MPMS Chapter 21 -- Chapters 21.1 - Electronic Gas Systems, and Chapter 21.2 - Liquid Electronic Systems address the ability to audit and verify the information produced by a flow computer, and defines the data which a flow computer should retain, the items which should be audited if modified, the reports which the system will be capable of producing and the methodologies to follow.Algorithms one can expect to see implemented in a typical gas flow computer are AGA Report No. 3, AGA Report No. 7, AGA Report No. 8. Additional to natural gas, some flow computers offer an array of density calculations for steam, oxygen, hydrogen, nitrogen, and ethylene. Complex algorithms and Equations of State for wide ranges of hydrocarbon fluids and petrochemicals can also be found in liquid flow computers. API MPMS Chapter 11.1 (2004), NIST 1045 and IUPAC for ethylene
Ethylene
Ethylene is a gaseous organic compound with the formula . It is the simplest alkene . Because it contains a carbon-carbon double bond, ethylene is classified as an unsaturated hydrocarbon. Ethylene is widely used in industry and is also a plant hormone...
measurement, GPA TP-27 for LPGs and NGLs are amongst an array of calculations performed by liquid flow computers. Other corrections specific to particular types or manufacturers of flow meters may also be implemented. Flow computers can include meter viscosity linearization functions for various meter types such as helical turbine meters, and interface serially with ultrasonic meters to obtain flow and diagnostic data.
Flow computers are available as completely programmable devices or as configurable devices using manufacturer's specific configuration software packages to setup interfaces to gas chromatographs, gas ultrasonic meters, liquid provers, flow control valve
Valve
A valve is a device that regulates, directs or controls the flow of a fluid by opening, closing, or partially obstructing various passageways. Valves are technically pipe fittings, but are usually discussed as a separate category...
s, PLC
Programmable logic controller
A programmable logic controller or programmable controller is a digital computer used for automation of electromechanical processes, such as control of machinery on factory assembly lines, amusement rides, or light fixtures. PLCs are used in many industries and machines...
, DCS
Distributed control system
A distributed control system refers to a control system usually of a manufacturing system, process or any kind of dynamic system, in which the controller elements are not central in location but are distributed throughout the system with each component sub-system controlled by one or more...
, SCADA
SCADA
SCADA generally refers to industrial control systems : computer systems that monitor and control industrial, infrastructure, or facility-based processes, as described below:...
and industry-recognized HMI supervisory systems. Higher-level flow computers are also supported by OLE for process control
OLE for process control
OLE for Process Control , which stands for Object Linking and Embedding for Process Control, is the original name for a standards specification developed in 1996 by an industrial automation industry task force...
drivers such as MatrikonOPC, KEPware and Autosol to create efficient data transfers on networks. Modbus
Modbus
Modbus is a serial communications protocol published by Modicon in 1979 for use with its programmable logic controllers . Simple and robust, it has since become one of the de facto standard communications protocols in the industry, and it is now amongst the most commonly available means of...
/TCP is a standard offering via Ethernet
Ethernet
Ethernet is a family of computer networking technologies for local area networks commercially introduced in 1980. Standardized in IEEE 802.3, Ethernet has largely replaced competing wired LAN technologies....
interfaces from some flow computers. Security issues are very significant in SCADA system development using flow computers. Recognized industry leaders in specialty flow computers are companies such as Eagle Research Corp., OMNI
Omni
Omni is a Latin prefix meaning "all" or "every." Omni may also refer to:-Mormonism:* Omni , a person in the Book of Mormon* The Book of Omni, one of the books in the Book of Mormon-Vehicles:...
and Emerson
Emerson Electric Company
Emerson Electric Company is a major multinational corporation headquartered in Ferguson, Missouri, United States. This Fortune 500 company manufactures products and provides engineering services for a wide range of industrial, commercial, and consumer markets.Emerson is one of the largest...
. The new generation flowcomputers of Krohne Oil and Gas has even more capabilities, like VGA touchscreen with supervisory like screen to operate valves and flow settings. Even a web Server onboard to access the reports and supervisory like displays.
And this trough a simple web browser.
A key component in custody transfer systems, flow computers can be approved to meterological and quality standards such as OIML R117-1 for liquids, EN12405 for gas, WELMEC 7.2 for software development, and ISO 9001:2008. These are considered key selection criteria for flow computers that are installed in Europe
Europe
Europe is, by convention, one of the world's seven continents. Comprising the westernmost peninsula of Eurasia, Europe is generally 'divided' from Asia to its east by the watershed divides of the Ural and Caucasus Mountains, the Ural River, the Caspian and Black Seas, and the waterways connecting...
, Middle East
Middle East
The Middle East is a region that encompasses Western Asia and Northern Africa. It is often used as a synonym for Near East, in opposition to Far East...
and Asia
Asia
Asia is the world's largest and most populous continent, located primarily in the eastern and northern hemispheres. It covers 8.7% of the Earth's total surface area and with approximately 3.879 billion people, it hosts 60% of the world's current human population...
.