Washer

The ascension tube D ca. i cm. in diameter ) rises for about 8 cm. above A, then narrows (5 mm. in diameter) to form a small condenser E (8 cm. long). The ascension tube then bends over in a flattened U-shape and descends into the gas-washer F (ca. 8 cm. long). The tube continues to the bottom of the washer, leaving a gap of only 1-2 mm. when F is closed by the insertion of the rubber bung M. The tube in this section is 2-3 mm. in diameter. The outlet tube... 

Belleville washers Bell furnace Bellodgia Bellows... 

War gases Washcoats Washers Washing Washing fastness... 

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. 

Another method of moderate dehumidification is by direct contact between the air and cold water using open circuit equipment. An air washer or capillary humidifier maintaining the water at a cold temperature is an example. 

Chemical Neutralization. Spray-type air washers are used extensively for removal or neutrali2ation of noxious components from large volumes of air, particularly exhaust air streams. Appropriate reagents are sprayed into the washer to purify the air by neutrali2ation, eg, sodium hydroxide solution is used if the air contains acidic gases. The solution must be continuously reconcentrated and any precipitated salts removed. The contact efficiency of such washers is high, and the simple constmction provides easy maintenance and constant efficiency (see AiRPOLLUTlON CONTROL METHODS). 

Power Washing. Power washing is similar to steam cleaning, except that the cleaner is injected into a high pressure (6.9—35 MPa (1000—5000 psi)) water blast in power washing. The water can be cold, warm, or hot, because the power washer is fed from a water tap. 

Fig. 1. Flow sheet for conventional scrap mica washer plant. See text.

An all aromatic polyetherimide is made by Du Pont from reaction of pyromelUtic dianhydride and 4,4 -oxydianiline and is sold as Kapton. It possesses excellent thermal stabiUty, mechanical characteristics, and electrical properties, as indicated in Table 3. The high heat-deflection temperature of the resin limits its processibiUty. Kapton is available as general-purpose film and used in appHcations such as washers and gaskets. Often the resin is not used directly rather, the more tractable polyamide acid intermediate is appHed in solution to a surface and then is thermally imidi2ed as the solvent evaporates. 

Washing equipment typically includes cylinder or dmm washers, diffusion ring washers, pressure diffusers, pressure washers, and belt washers. 

Fig. 23. Flow sequence for countercurrent rotary brown-stock washers (29).

The white Hquor is separated from the calcium carbonate by decantation in a clarifier and is then available for a new cooking cycle. The underflow from the clarifier, which contains the calcium carbonate and is referred to as lime mud, is diluted with water and passed to a second clarifier known as the lime mud washer. The clarified weak white Hquor (weak wash) goes to storage and then enters the dissolving tank. The lime mud residue from the lime mud washer is passed to a rotary filter and subsequently to the lime kiln where calcium carbonate is converted back to calcium oxide, thus completing the lime cycle. 

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