A flow computer is an electronic computer which implements algorithms using the analog and digital signals received from flow meters, temperature, pressure and density transmitters to which it is connected into volumes at

base conditions Base conditions, also known as standard 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 ...

. They are used for custody or fiscal transfer. It also audits changes that have been made to any of the parameters required to turn the raw

flow meter Flow measurement is the quantification of bulk fluid movement. Flow can be measured in a variety of ways. The common types of flowmeters with industrial applications are listed below: * a) Obstruction type (differential pressure or variable area) ...

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 keeps a running tally of the volume for each flow meter it monitors and creates a record of this volume on an hourly, daily, batch or monthly basis. The flow data is made available externally through an electronic interface so that other computers can download the information for supervision, accounting and auditing.

(API) MPMS (Manual of Petroleum Measurement Standards) 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 in the U.S. market. Internationally, ISO 5167-1:2003 and other ISO gas standard equivalents are in widespread use. 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 The National Institute of Standards and Technology (NIST) is an agency of the United States Department of Commerce whose mission is to promote American innovation and industrial competitiveness. NIST's activities are organized into physical sci ...

1045 and

IUPAC The International Union of Pure and Applied Chemistry (IUPAC ) is an international federation of National Adhering Organizations working for the advancement of the chemical sciences, especially by developing nomenclature and terminology. It is ...

for

ethylene Ethylene (IUPAC name: ethene) is a hydrocarbon which has the formula or . It is a colourless, flammable gas with a faint "sweet and musky" odour when pure. It is the simplest alkene (a hydrocarbon with carbon-carbon double bonds). Ethylene i ...

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

s 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 using a variety of software tools or as configurable devices using manufacturer's specific configuration software packages to set up interfaces to gas chromatographs, gas ultrasonic meters, liquid provers, flow control

valve A valve is a device or natural object that regulates, directs or controls the flow of a fluid (gases, liquids, fluidized solids, or slurries) by opening, closing, or partially obstructing various passageways. Valves are technically fittings ...

s, PLC, DCS,

SCADA Supervisory control and data acquisition (SCADA) is a control system architecture comprising computers, networked data communications and graphical user interfaces for high-level supervision of machines and processes. It also covers sensors and ...

and industry-recognized HMI supervisory systems. Modbus/TCP is a standard offering via

Ethernet Ethernet () is a family of wired computer networking technologies commonly used in local area networks (LAN), metropolitan area networks (MAN) and wide area networks (WAN). It was commercially introduced in 1980 and first standardized in 198 ...

interfaces from some flow computers, although other communications protocols, such as OLE are supported by some flow computers. Security issues are very significant in SCADA system development using flow computers. A key component in custody transfer systems, flow computers can be approved to

metrological Metrology is the scientific study of measurement. It establishes a common understanding of units, crucial in linking human activities. Modern metrology has its roots in the French Revolution's political motivation to standardise units in Fra ...

and quality standards such as

OIML R117-1 The International Organization of Legal Metrology (french: Organisation Internationale de Métrologie Légale - OIML), is an intergovernmental organisation that was created in 1955 to promote the global harmonisation of the legal metrology procedur ...

for liquids,

EN12405 The EN postcode area, also known as the Enfield postcode area,Royal Mail, ''Address Management Guide'', (2004) is a group of eleven postcode districts in England, within seven post towns. These cover parts of northern Greater London (including ...

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 is a large peninsula conventionally considered a continent in its own right because of its great physical size and the weight of its history and traditions. Europe is also considered a Continent#Subcontinents, subcontinent of Eurasia ...

Middle East The Middle East ( ar, الشرق الأوسط, ISO 233: ) is a geopolitical region commonly encompassing Arabian Peninsula, Arabia (including the Arabian Peninsula and Bahrain), Anatolia, Asia Minor (Asian part of Turkey except Hatay Pro ...

Asia Asia (, ) is one of the world's most notable geographical regions, which is either considered a continent in its own right or a subcontinent of Eurasia, which shares the continental landmass of Afro-Eurasia with Africa. Asia covers an area ...

and also Latin America.

References

External links

*http://swintontechnology.com
http://www.sgc-valid8.com
-- Free online Flow Measurement Calculation and Verification Engine {{DEFAULTSORT:Flow Computer Control devices

See also

References

External links