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Air Ducting

The outlet holes in the duct are designed to discharge air at such a velocity that the airstream reaches the walls and passes down to (he floor without directly hitting the top containers. The holes are spaced so that the boundaries of the adjacent jets meet just before reaching the wall or floor. This effectively eliminates dead-air pockets. To size and space the outlet holes exactly, two guidelines are [Pg.70]

The total surface area of the holes is equal to the cross section of the duct. (The area of a circle is22/7times (he radius squared, A= (r) ). [Pg.70]

The space between the holes is equal to a quarter of the distance between the duct and the wall or floor. [Pg.70]

The discharge of air at velocities sufficient to draw in surrounding room air is called entrainment, a phenomenon that enhances the capacity of the air circulation system. A flow pattern of even air is (hen reached that directly benefits the growing mushrooms. The entrainment of air is the goal of air management in the growing room. [Pg.70]


Side and bottom supply return air duct openings (side x side)... [Pg.361]

Humidification. For wiater operation, or for special process requirements, humidification maybe required (see Simultaneous HEAT and mass transfer). Humidification can be effected by an air washer which employs direct water sprays (see Evaporation). Regulation is maintained by cycling the water sprays or by temperature control of the air or water. Where a large humidification capacity is required, an ejector which direcdy mixes air and water in a no22le may be employed. Steam may be used to power the no22le. Live low pressure steam can also be released directly into the air stream. Capillary-type humidifiers employ wetted porous media to provide extended air and water contact. Pan-type humidifiers are employed where the required capacity is small. A water filled pan is located on one side of the air duct. The water is heated electrically or by steam. The use of steam, however, necessitates additional boiler feed water treatment and may add odors to the air stream. Direct use of steam for humidification also requires careful attention to indoor air quahty. [Pg.362]

Because of its small size and portabiHty, the hot-wire anemometer is ideally suited to measure gas velocities either continuously or on a troubleshooting basis in systems where excess pressure drop cannot be tolerated. Furnaces, smokestacks, electrostatic precipitators, and air ducts are typical areas of appHcation. Its fast response to velocity or temperature fluctuations in the surrounding gas makes it particularly useful in studying the turbulence characteristics and rapidity of mixing in gas streams. The constant current mode of operation has a wide frequency response and relatively lower noise level, provided a sufficiently small wire can be used. Where a more mgged wire is required, the constant temperature mode is employed because of its insensitivity to sensor heat capacity. In Hquids, hot-film sensors are employed instead of wires. The sensor consists of a thin metallic film mounted on the surface of a thermally and electrically insulated probe. [Pg.110]

Compounds based on S—EB—S usually contain polypropylene, which improves solvent resistance and processibiUty and raises upper service temperatures. Compounds intended for use in the automotive industry are able to survive 1000 hours air exposure at temperatures of 125°C with only minor changes in properties (54). Very soft compounds have been developed to replace foam mbber for interior trim parts. In this and similar appHcations, these soft compounds are usually insert molded over polypropylene or metal and then coated with flexible polyurethane paint (55). Other automotive appHcations include products intended for sound deadening, flexible air ducts, and gear shifter boots, as weU as improving the properties of sheet mol ding compounds. [Pg.18]

Another area which is of considerable interest is the development of rotationally moulded products. These mouldings include air ducting housing and a 700-litre frozen food container, both of which are greater than 20 kg in weight. [Pg.577]

Cigarette smoke Pipe lagging Air duct linings Ceiling and roof tiles Asbestos cement sheeting Synthetic fibres Plastics... [Pg.142]

Flare smoke suppression system consisting of an air duct mixing section, air nozzle ring header and associated duct work from ground level to fire tip. [Pg.311]

This type consists of an enclosed water tank, which is connected to the main air duct. [Pg.720]

Consider next the fan with its connected air duct characteristics when both are operating together. We indicate the fan leaving air by siibscripr 2 and the suction side by subscript 1. [Pg.767]

For a special fan situation, a straight air duct of uniform cross-sectional area is used on the leaving side. The outgoing velocity Cj is the same as the fan leaving velocity C2. The only minor loss is the outgoing loss = pcT Another part of the pressure drop is the frictional pressure drop Ap, . Equation (9.127) gives... [Pg.767]

In air ducts, the measurement of the local air vekxiity is used to determine the flow rate in the duct. The duct flow is usually more stable and the flow direction under better control than in the room space. Different types of disturbances in the ductwork, such as bends, tees, or dampers, will influence the nature of the flow and cause swirl and other problems in velocity measurement. [Pg.1152]

As the measuring distance for such equipment can be up to about. 50 m, this technique is advantageous in cases when conventional acoustic or vibro-meter devices are difficult or even impossible to use, such as high-frequency vibration measurements on the walls of high-level air ducts. [Pg.1172]

Air duct An enclosure that conveys air from one location to another. [Pg.1408]

Primary air induction system Air introduced via an air duct to the induction unit, generally in the form of treated outdoor air. [Pg.1469]

Wind-kanal, m. air passage, air duct, -kastea, m. wind chest, air chamber Metal.) twyer box. -kessel, m. blast pressure tank, blast box air chamber, -leitung,/. Metal.) blast main, -leitungsrohr, n. Metal.) blast pipe, -messer, m. wind meter, anemometer blast gage, -miihle, /. windmill, -ofen, m. wind fiirnace, air furnace, -ppcken, f.pl, chicken pox. -pressung, /. Metal.) blast pressure, -lohr, n. Metal.) blast pipe, twT r pipe, -sammler, m. air reservoir, compressed-air tank. [Pg.515]

Heat loss from distribution pipes and air ducts. [Pg.542]

Apart from such requirements for head pressure control, winter precautions are needed to prevent freezing of the water while the plant is not rejecting heat to it. These commonly take the form of an electric immersion heater in the water tank, together with lagging and possible trace heating of exposed pipes. In some systems, the evaporative condenser itself may be within the building, with air ducts to the outside. In severe climates, external tanks need to be lagged to conserve the heat provided by the immersion heater. [Pg.79]

It is sometimes necessary to assist the distribution of air from the cooler by installing air ducting. This can take the form of individual ducts, but these are prone to damage from fork-lift trucks. Alternatively, a full or partial false ceiling, below the insulated surface. [Pg.185]

With a supply system pressure of 1 kPa and another 250 Pa for the return air duct, the total fan energy of a central all-air system may amount to 12.5% of the maximum installed cooling load, and a much greater proportion of the average operating load. This power loss can only be reduced by careful attention to design factors. [Pg.305]

Automotive (interior and exterior parts, air ducts, crash pads, arm rests, etc.)... [Pg.242]

It was decided to give the large room a 9 foot ceiling, while ceiling height in the other rooms would be the standard 8 feet. Adequate space would be allowed above the ceilings to carry overhead utilities and air ducts. [Pg.142]


See other pages where Air Ducting is mentioned: [Pg.117]    [Pg.353]    [Pg.478]    [Pg.503]    [Pg.325]    [Pg.241]    [Pg.937]    [Pg.305]    [Pg.806]    [Pg.806]    [Pg.1156]    [Pg.1240]    [Pg.283]    [Pg.283]    [Pg.283]    [Pg.284]    [Pg.54]    [Pg.540]    [Pg.1053]    [Pg.81]    [Pg.441]    [Pg.257]    [Pg.283]    [Pg.303]    [Pg.305]    [Pg.492]    [Pg.1026]    [Pg.171]   


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