Inlet area

Poor performance can result from fan inlet eccentric or spinning dow, and discharge ductwork that does not permit development of hiU fan pressure. Sometimes inlet restrictions starve a fan and limit performance. To obtain rated performance, the air must enter the fan uniformly over the inlet area without rotation or unusual turbulence. This allows all portions of the fan wheel to do equal work. If more air is distributed to one side of the wheel, such as with an elbow on the inlet, the work performed by the lightiy loaded portions of the wheel is reduced and capacity is decreased by 5—10%. The use of an inlet box duct on a fan can reduce capacity by as much as 25% unless there are turning vanes in the duct. Use of the vanes reduces the capacity loss to around 5%. 

For a properly designed and operated cyclone, the sharpness iadex is constant, typically 0.6. The cut size and apparent bypass are a function of the cyclone geometry, the volumetric feed rate, the material relative density, the feed soflds concentration, and the slurry rheology. The relationship for a standard cyclone geometry, where if is the cylinder diameter ia cm and inlet area = 0.05 vortex finder diameter = 0.35 ... 

Example 3 Venturi Flowmeter An incompressible fluid flows through the venturi flowmeter in Fig. 6-7. An equation is needed to relate the flow rate Q to the pressure drop measured by the manometer. This problem can he solved using the mechanical energy balance. In a well-made venturi, viscous losses are neghgihle, the pressure drop is entirely the result of acceleration into the throat, and the flow rate predicted neglecting losses is quite accurate. The inlet area is A and the throat area is a. 

Barrel friction. The inlet diameter is taken as 4 X (inlet area)/ inlet perimeter. Then,... 

The inlet area at the blade tip ean be ealeulated using the eontinuity equation... 

The entire inlet line must be at least the size of the PR valve inlet. When multiple safety valves are manifolded on the inlet side, the cross-sectional area of the maitifold piping must be equal to or greater than the sum of all the inlet areas of valves open to the manifold. 

Based on the static pressure across the inlets, = p Ap, one can calculate the required inlet area, A,, ... 

These are made up of a large number of wide, shallow blades with a very large inlet area relative to the wheel diameter. For equal duty the speeds are lower than other centrifugal fans. They are sometimes called multivane the operating efficiencies are in the 65-75% range. They consist of a large number of relatively small blades mounted on the impeller. The blade tips are inclined toward the direction of rotation. The actual flow rate can be 2.5 times as high as the same size backward-curved fan. 

When calculating the velocity potential at a point near an infinitely flanged exhaust opening, the hood face can be assumed to be divided into many area sinks, each of them contributing to the potential at a point in space. The overall velocity potential is then obtained by integrating over the inlet area. The velocity component in the. v direction, for example, is then... 

Specific surface area, sq ft/cu ft Acceleration due to gravity, 32.2 ft/s or 9.8 m/s Area of segment of a circle, sq ft Cro.ss-sectional flow area, sq ft Cross-sectional area at bottom of vessel occupied by continuous aqueous phase, sq ft Cyclone inlet area = WjH,- for cyclone wdtb rectangular inlet, sq ft... 

Nye Tray, 10-20% increased tray (over sieve or valve) capacity and good efficiency. More capacity from existing column. Improved inlet area for sieve or valve tray with greater area for vapor-liquid disengagement. 

The Nye Tray increases the area available for disengagement of this light froth. In addition to the normal perforated section, vapor can now flow into the Inlet area below the downcomer. Vapor enters the contact zone of the Nye Tray through the perforated face of the inlet panel, under the liquid coming out of the downcomer. 

Specifically, the Nye Tray achieves this Improvement by using a patented inlet area on a sieve or valve tray, which increases the area available for vapor-llquid disengagement. 

Holes for drainage must be adequate to drain the column in a reasonable time, yet not too large to interfere with tray action. Draining of the column through the trays is necessary before any internal maintenance can be started or before fluid services can be changed, when mixing is not desirable. The majority of holes are placed adjacent to the outlet or downcomer weir of the tray. However, some holes are placed in the downcomer inlet area or any suspected low point in the mechanical layout of the column. 

Inlet area that causes the gas to flow tangentially,... 

The pressure drop and the friction loss through a cyclone are most conveniently expressed in terms of the velocity head based on the immediate inlet area. The inlet velocity head, h i, which is expressed in inches of water, is related to the average inlet-gas velocity and density by ... 

Ab = Cross-sectional area at bottom of vessel occupied by continuous aqueous phase, sq ft Ac = Cyclone inlet area = WjHc for cyclone wiLh rectangular inlet, sq ft... 

All cyclone design procedures bear the inherent condition that the solids enter uniformly dispersed over the cyclone s inlet area. This is generally the case where a cyclone is hung inside a vessel above a... 

An air inlet area of at least 400 cm2 and a louvered exit of 75 cm2 are recommended for target capacity and physical size of the appliance. The efficient and quiet centrifugal fan unit is popularly used in air conditioners and air purifiers. It costs less than the other fan units of similar size and is easy to install and assemble. A fan with adjustable air deliver rate of 0 to 250 cfm will be used to draw air through the air filter, dehumidifier and purifier units. A smaller fan with air delivery rate of up to 10 cfm is needed for the regeneration... 

Nitrates can be used as complements or alternatives to oxygen, both for energy saving and for the treatment of industrial wastes. This is the background for the Kraus modification of the activated sludge process. Similarly an anoxic zone in the inlet area of the aerator can be applied (11). 

The essential parts of a gas chromatograph as shown in Figure 8.1 are carrier gas, flow or pressure regulator, injection port or valve, column, and detector. Usually there are three heated zones, each separately controlled, for the inlet area, the column, and the detector. Connections between these heated zones must also be kept hot enough to prevent condensation of analytes in them. Chromatographs designed for OT columns usually have additional features a more elaborate injection port that allows for sample splitting and a provision for some additional make-up gas for the detector. Information about commercial instruments can be found in the review by Bayer.3... 

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