Wright dust feeder

Dust dispersion—Aerosols of mineral particles and a few other materials may be prepared by dust dispersal techniques. A number of dust dispersal devices have been constructed. A commonly used device is the Wright Dust Feeder. In this device the dust is compressed into a cylindrical compact, which is placed in an electronically driven mechanism that rotates it and drives it against a fixed knife blade at a fixed rate. Material is scraped off the compact by the blade, entrained in an air stream, and blown against a metal plate to break up particle aggregates. 

Figure 4. Dust generation system the Wright dust feeder introduces dust into the air stream at a constant rate to produce test atmospheres.

A more widely used dust generator has been the Wright dust feeder [60], A diagram of the commercially available model is shown in Fig. 9. The powder... 

Figure 9 Commercial version of the Wright dust feeder. (A) dust chamber, (B) cap, (C) long pinion, (D) gear, (E) small pinion, (F) treaded spindle, (J) inner tube, (G) main spundle, (K) scraper head, (M) impaction plate, (N) spring ring, (O) scraper blade.

E-C, evaporation-condensation N, nebulizer EC, electrostatic classifier VO, vibrating orifice SD, spinning disc FD, fluidized bed RB, rotating brush WDF, Wright dust feeder NBS, NBS dust generator. Values of parameters given are from specifications listed by TSI, Inc., and BGI, Inc. Stability data are from the references. A density of / g/m3 is assumed for the mass concentration values. 

Collision nebulizer, spinning-top aerosol generator, NBS dust generator, Timbrell dust generator, Wright dust feeder SAFEX fog generators... 

The method for generating the required atmospheric dispersion of anti-ChE (e.g.. as vapor or aerosol). Highly volatile and/or reactive liquids may have to be metercd from stainless-stce cylinders (Dodd etal.. 1986). For generation of liquid aerosols of respirable size, the La,skin nebulizer is suitable for one-component test materials (Drew et at., 1978) and for generation of du.st particles, the Wright dust feeder is commonly used. 

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