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Flowmeters
Flow measurement is the quantification of bulk fluid movement. Flow can be measured using devices called flowmeters in various ways. The common types of flowmeters with industrial applications are listed below: * Obstruction type (differential pressure or variable area) * Inferential (turbine type) * Electromagnetic * Positive-displacement flowmeters, which accumulate a fixed volume of fluid and then count the number of times the volume is filled to measure flow. * Fluid dynamic (vortex shedding) * Anemometer * Ultrasonic flow meter * Mass flow meter (Coriolis force). Flow measurement methods other than positive-displacement flowmeters rely on forces produced by the flowing stream as it overcomes a known constriction, to indirectly calculate flow. Flow may be measured by measuring the velocity of fluid over a known area. For very large flows, tracer methods may be used to deduce the flow rate from the change in concentration of a dye or radioisotope. Kinds and units of measure ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Positive Displacement Meter
A positive displacement meter is a type of flow meter that requires fluid to mechanically displace components in the meter in order for flow measurement. Positive displacement (PD) flow meters measure the volumetric flow rate of a moving fluid or gas by dividing the media into fixed, metered volumes (finite increments or volumes of the fluid). A basic analogy would be holding a bucket below a tap, filling it to a set level, then quickly replacing it with another bucket and timing the rate at which the buckets are filled (or the total number of buckets for the “totalized” flow). With appropriate pressure and temperature compensation, the mass flow rate can be accurately determined. These devices consist of a chamber(s) that obstructs the media flow and a rotating or reciprocating mechanism that allows the passage of fixed-volume amounts. The number of parcels that pass through the chamber determines the media volume. The rate of revolution or reciprocation determines the flo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Magnetic Flow Meter
{{Short description, Device for measuring flow of a fluid A ''magnetic flow meter'' (mag meter, electromagnetic flow meter) is a transducer that measures fluid flow by the voltage induced across the liquid by its flow through a magnetic field. A magnetic field is applied to the metering tube, which results in a potential difference proportional to the flow velocity perpendicular to the flux lines. The physical principle at work is electromagnetic induction. The magnetic flow meter requires a conducting fluid, for example, water that contains ions, and an electrical insulating pipe surface, for example, a rubber-lined steel tube. If the magnetic field direction were constant, electrochemistry, electrochemical and other effects at the electrodes would make the potential difference difficult to distinguish from the fluid flow induced potential difference. To show this in modern magnetic flowmeters, the magnetic field is constantly reversed, cancelling out the electrochemical potent ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ultrasonic Flow Meter
An ultrasonic flow meter is a type of flow meter that measures the velocity of a fluid with ultrasound to calculate volume flow. Using ultrasonic transducers, the flow meter can measure the average velocity along the path of an emitted beam of ultrasound, by averaging the difference in measured transit time between the pulses of ultrasound propagating into and against the direction of the flow or by measuring the frequency shift from the Doppler effect. Ultrasonic flow meters are affected by the acoustic properties of the fluid and can be impacted by temperature, density, viscosity and suspended particulates depending on the exact flow meter. They vary greatly in purchase price but are often inexpensive to use and maintain because they do not use moving parts, unlike mechanical flow meters. Means of operation There are three different types of ultrasonic flow meters. Transmission (or contrapropagating transit-time) flow meters can be distinguished into in-line (intrusive, we ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Thermal Mass Flow Meter
Thermal mass flow meters, also known as thermal dispersion or immersible mass flow meters, comprise a family of instruments for the measurement of the total mass flow rate of a fluid, primarily gases, flowing through closed conduits. A second type is the capillary-tube type of thermal mass flow meter. Many mass flow controllers (MFC) which combine a mass flow meter, electronics and a valve are based on this design. Furthermore, a thermal mass flow meter can be built by measuring temperature differential across a silicon-based MEMS chip. Both types measure fluid mass flow rate by means of the heat convected from a heated surface to the flowing fluid. In the case of the thermal dispersion, or immersible, type of flow meter, the heat is transferred to the boundary layer of the fluid flowing over the heated surface. In the case of the capillary-tube type, the heat is transferred to the bulk of the fluid flowing through a small heated capillary tube. The principles of operation ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ultrasonic Flow Meter
An ultrasonic flow meter is a type of flow meter that measures the velocity of a fluid with ultrasound to calculate volume flow. Using ultrasonic transducers, the flow meter can measure the average velocity along the path of an emitted beam of ultrasound, by averaging the difference in measured transit time between the pulses of ultrasound propagating into and against the direction of the flow or by measuring the frequency shift from the Doppler effect. Ultrasonic flow meters are affected by the acoustic properties of the fluid and can be impacted by temperature, density, viscosity and suspended particulates depending on the exact flow meter. They vary greatly in purchase price but are often inexpensive to use and maintain because they do not use moving parts, unlike mechanical flow meters. Means of operation There are three different types of ultrasonic flow meters. Transmission (or contrapropagating transit-time) flow meters can be distinguished into in-line (intrusive, we ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Quantity (physics)
A physical quantity (or simply quantity) is a property of a material or system that can be quantified by measurement. A physical quantity can be expressed as a ''value'', which is the algebraic multiplication of a ''numerical value'' and a ''unit of measurement''. For example, the physical quantity mass, symbol ''m'', can be quantified as ''m'n''kg, where ''n'' is the numerical value and kg is the unit symbol (for kilogram). Quantities that are vectors have, besides numerical value and unit, direction or orientation in space. Components Following ISO 80000-1, any value or magnitude of a physical quantity is expressed as a comparison to a unit of that quantity. The ''value'' of a physical quantity ''Z'' is expressed as the product of a ''numerical value'' (a pure number) and a unit 'Z'' :Z = \ \times /math> For example, let Z be "2 metres"; then, \ = 2 is the numerical value and = \mathrm is the unit. Conversely, the numerical value expressed in an arbitrary unit can be ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bushel
A bushel (abbreviation: bsh. or bu.) is an Imperial unit, imperial and United States customary units, US customary unit of volume, based upon an earlier measure of dry capacity. The old bushel was used mostly for agriculture, agricultural products, such as wheat: in modern usage, the volume is nominal, with bushels denoting a mass defined differently for each commodity. The name "bushel" is also used to translate similar units in other measurement systems. Name The word "bushel" as originally used for a container itself, and later a unit of measurement. The name comes from the Old French ' and ', meaning "little box".. It may further derive from Old French ', thus meaning "little butt (unit), butt". History The bushel is an intermediate value between the pound (mass), pound and ton or tun (unit), tun that was introduced to England following the Norman Conquest of England, Norman Conquest. Norman England, Norman Weights and Measures Acts (UK), statutes made the London ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Water Distribution System
A water distribution system is a part of water supply network with components that carry potable water from a Water treatment, centralized treatment plant or wells to consumers to satisfy residential, commercial, industrial and fire fighting requirements. Definitions Water distribution network is the term for the portion of a water distribution system up to the service points of bulk water consumers or demand nodes where many consumers are lumped together. The World Health Organization (WHO) uses the term water transmission system for a network of pipes, generally in a tree-like structure, that is used to convey water from water treatment plants to Reservoir#Service, service reservoirs, and uses the term water distribution system for a network of pipes that generally has a loop structure to supply water from the service reservoirs and Reservoir#Flow balancing, balancing reservoirs to consumers. Components A water distribution system consists of pipelines, storage facilities, pum ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
American Gas Association
The American Gas Association (AGA) is an American trade organization founded in 1918 representing and advocating on behalf of local energy companies which deliver natural gas throughout the United States. History The American Gas Association was formed in June 1918 after the merger of the American Gas Institute and the National Commercial Gas Association, organizations serving the interests of companies that dealt in manufactured, as opposed to natural, gas. Manufactured gas was the dominant fuel in the early United States; during the 19th century natural gas supplanted it. In January 1919, the AGA launched a publication for the natural gas industry providing information on trends, activities, and strategies on how to improve gas companies. In 1925, the association formed laboratories in Cleveland, and five years later expanded to Los Angeles. These labs developed technology to improve gas appliances and equipment, making them more energy-efficient and consumer-friendly. The lab ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nutation
Nutation () is a rocking, swaying, or nodding motion in the axis of rotation of a largely axially symmetric object, such as a gyroscope, planet, or bullet in flight, or as an intended behaviour of a mechanism. In an appropriate reference frame it can be defined as a change in the second Euler angle. If it is not caused by forces external to the body, it is called free nutation or Euler nutation (after Leonhard Euler). A pure nutation is a movement of a rotational axis such that the first Euler angle is constant. Therefore it can be seen that the circular red arrow in the diagram indicates the combined effects of precession and nutation, while nutation in the absence of precession would only change the tilt from vertical (second Euler angle). However, in spacecraft dynamics, precession (a change in the first Euler angle) is sometimes referred to as nutation. In a rigid body If a top is set at a tilt on a horizontal surface and spun rapidly, its rotational axis starts precess ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
