Powder spraying

Wettable powders are prepared by blending the toxicant in high concentration, usually from 15 ndash 95%, with a dust carrier such as attapulgite which wets and suspends properly in water. One to two percent of a surface-active agent usually is added to improve the wetting and suspensibiUty of the powder. Sprays of wettable powders are used widely in agriculture because of their relative safety to plants. 

Fig. 5. Schematic diagram of an electrostatic powder spray system. Courtesy of Nordson Corp.

There were over 3000 electrostatic powder spray lines and about 800 other powder coating installations operating in the United States as of 1991. Eor additional general information on the safety aspects of powder coatings, see References 90, 93, and 94. 

In recent years increasing use has been made by many manufacturers, who require a limited range of colours, of the electrostatic application of a dry powder spray. Dry electrostatic finishes are fused at temperatures in the same range as conventional ones. 

Aqueous or alcoholic (70%) solution Mouthwash Dry powder spray Scalp and skin cleanser... 

The residual toxicity of the pure gamma isomer was found to be equivalent to that of ordinary commercial benzene hexachloride. Commercial usage has shown that the residual action is effective for a longer time with dust or wettable powder spray applications than with emulsive solvent-type formulations. The over-all residual life of the chemical is on the order of 4 to 8 days as compared to 14 to 21 days for DDT. This is, of course, adequate residual life for good insect control in most cases and the shorter... 

Schematic representation of the DLR (dry powder spraying) CCM manufacturing process. (Reproduced from Wagner, N., Kaz, T., and Friedrich, K. A. Electmchimica Acta 2008 53 7475-7482. With permission from Elsevier.)...

Topical 2% cream, powder, spray 100, 200 mg vaginal suppositories Micafungin (Mycamine)... 

Miconazole, 2% (cream, powder, solution), apply to affected areas twice daily (morning and night) Cruex, Desenex, Lotrimin AF (powder, spray), Zeasorb-AF ... 

Dishwashing Detergent. Powdered. Spray Mixing Process-A... 

Application Use 3-5 g/1 water (depending on water hardness) Dishwashing Detergent, Powdered, Spray Mixing Process-B... 

Detergent for Colored Fabrics Powder, Spray Mixing.Process-B... 

Light-Duty Detergent, Powder, Spray. Mixina Process-B... 

When a lactose solution is dried rapidly, its viscosity increases so quickly that crystallization cannot take place. The dry lactose is essentially in the same condition as it was in solution, except for removal of the water. This is spoken of as a concentrated syrup or an amorphous (noncrystalline) glass. Various workers have shown conclusively that lactose in milk powder (spray, roller, or freeze-dried) is noncrystalline and exists in the same equilibrium mixture of a- and /3-lactose as existed in the milk prior to drying (Zadow 1984). 

Maa, Y., Nguyen, P., Sweeney, T., et al. Protein inhalation powders Spray drying vs. spray freeze drying. Pharm. Res. 16(2) 249-254, 1999. 

Schindler, J., Meyer-Olbersleben, F., Kirbach, B., (1998), Fabrication of FGM-foils for joining application by wet powder spraying , presented at 5th International Symposium on Functionally Graded Materials, Dresden, October 1998. 

J. D. Findlay, C. Higginbottom, J. A. B. Smith, and C. H. Lea, The effect of the pre-heating temperature on the bacterial count and storage life of whole milk powder spray-dried by the Krause process, J. Dairy Res., 1946, 14, 378-399. 

Control of Drop Size w/o Emulsions. Although the control of the drift of herbicide sprays was the initial reason for renewed interest in water-in-oil emulsion sprays, there are other interesting and novel ways of applying pesticides. The physical properties of w/o emulsions are considerably different from those of more conventional types of spray liquids, and the emulsifiers required to form and stabilize w/o emulsions are different from the usual materials employed in oil-in-water and wettable powder sprays. These differences can affect all aspects of spray performance, and a thorough study is required to appreciate the advantages and disadvantages which w/o emulsions may possess over aqueous-based sprays. 

Morgan J.N., Armstrong, D.J. 1992. Quantification of cholesterol oxidation products in egg yolk powder spray-dried with direct heating. J. Food Sci. 57, 43-45. 

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