Rotating vane meter

The rotating vane meter, which is arranged in the radial direction to the flow, is the most well known and is used for flows of 1-4800 m h [4]. The measuring range is 1 10 with an accuracy of about 0.1% [4]. 

Rotating Vane Volumetric Flowmeter. A schematic drawing of a rotating vane meter is shown in Fig. 8.9. The dumbbell-shaped element rotates in a clockwise mode, while the two vanes rotate in a counterclockwise mode. The result is a measured quantity of fluid associated with the flowing fluid. 

Fig. 5. Operating sequence for a rotating-vane positive-displacement meter.

Solids Metering The control valves described earlier are primarily used for the control of fluid (liquid or gas) flow. Sometimes these valves, particularly the ball, butterfly, or sliding gate valves, are used to throttle dry or slurry solids. More often, special throttling mechanisms such as venturi ejectors, conveyers, knife-type gate valves, or rotating vane valves are used. The particular solids-metering valve hardware depends on the volume, density, particle shape, and coarseness of the solids to be handled. 

Current meters are hydrodynamic instruments with rotating vanes or buckets. The speed of their rotation is proportional to the flow velocity. The forerunners of current meters were the paddle wheels developed in the early 18 century. These were applied by Francesco Domenico Michelotti (1710-1777) in 1767, or by Pierre-Louis Du Buat (1734-1809) in 1786. There are two principal types of current meters, namely the screw and the cup types. The first was conceived by the famous British engineer Robert Hooke in 1783 to measure wind velocity with four vanes similar to a windmill. This type was developed by Reinhard Woltman (1757-1837) in 1790, Andre Baumgarten (1808-1859), Albert Ott (1847-1895), Alphonse Fteley (1837-1903) and Haskell, among many others. The other type meter has several cups on spokes rotating around an axis oriented transverse to the current. These anemometers were first applied around 1850 to measure wind velocities, and then were developed by Theodore Gunville Ellis (1829-1883), or William G. Price (1853-1928) to record flow velocity in rivers. 

Rotating-vane sealed drum, lobed impeller meters... 

Gup and Vane Anemometers. A number of flow meter designs use a rotating element kept in motion by the kinetic energy of the flowing stream such that the speed is a measure of fluid velocity. In general, these meters, if used to measure wind velocity, are called anemometers if used for open-channel Hquids, current meters and if used for closed pipes, turbine flow meters. 

Current Meters. Various vane designs have been adapted for open-channel flow measurement. The rotating element is partially immersed and rotates rather like a water wheel. Operation is similar to that of vane anemometers. 

U-shaped clevis to which a vaned tailpiece is attac-hed. The wheel rotates because of the difference in drag for the two sides of the cup, and a signal proportional to the revolutions of the wheel is generated. The velocity is determined from the count over a period or time. The current meter is generally usebil in the range of 0.15 to 4.5 m/s (about 0.5 to 15 ft/s) with an accuracy of 2 percent. For additional information see Creager and Justin, Hydroelectric Handbook, 2d ed., Wiley, New York, 1950, pp. 42-46. 

Current meter and rotating anemometer. These two, which are the same in principle, determine the velocity as a function of the speed at which a series of cups or vanes rotate about an axis either parallel to or normal to the flow. The instrument used in water is called a current meter, and when designed for use in air it is called an anemometer. As the force exerted depends on the density of the fluid as well as on its velocity, the anemometer must be so made as to operate with less friction than the current meter. 

Composition and Functions of the Apparatus. Figure 3 is a schematic diagram of the Rauter meter. An impeller rotating at high speed gives the air pressure torque to the second vane wheel in the chamber. This torque is measured and compared with that produced by an identical impeller arrangement in a standard gas (air). The Rauter meter has proven its worth through years of densitometric service. However, because it is a purely mechanical device, its speed of response and sensitivity are limited. Its speed of response is T9 0 i 30 seconds, and its maximum sensitivity to... 

Rotary-vane feeder n. A device for conveying and metering dry materials, comprising a cyhndrical housing containing a concentric shaft with blades or flutes attached, rotating at a rate selected to feed the material at a desired rate. 

Sheeu test using vane cone After loading by load meter, rod is careftiUy rotated by torque wrench. The above operation is repeated several times in different bad value. Initial torque and VCST angle are cabulated by these data set. 

Air velocities can be measmed by a variety of instruments but vane anemometers and heated head (hot wire or thermistor) air meters are the most common. Vane anemometers Figure 3.6.7) have a rotating windmill type head coupled to a meter and are most suitable for use in open... 

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Air motors use compressed air to create rotational motion. Compressed air flows through the motor, turning a positive displacement rotor with vanes that extend to the wall of the housing. Sufficient air must be compressed to provide the required flow and pressure at the motor. Losses through piping, valves, filters, and flow meters must be considered. 

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