Granules application

For control of organisms on the plant surface sufficient volatility to ensure vapour transfer is also desirable, particularly as most spray or granule applications leave a deposit in the form of discrete spots and a large proportion of the surface is effectively untreated. Approximate values may be assigned to the key properties in the light of experience... 

Figure 12.7. Rotating dish granulator applications and performance (Sherrington and Oliver, 1981). (a) Edge and face view of a dish granulator, diameters to 25 ft, Froudc no. n2D/gc = 0.5-0.8. (b) Stratification of particle sizes during rotation, (c) Typical applications of dish granulation (Dravo Corp.). (d) Capacity and power (Dravo Corp.). (e) Performance on cement kiln feed.

When suppurative wounds were treated with the widely used Vishnevsky ointment or synthomycin emulsion they soon became free from necrotic tissues to form rich granulations. Application of the l-(chloromethyl)silatrane ointment did not accelerate this process. The postoperatively silk-sutured wound healed at the proper time (7-10days). 

The effects of a number of parameters on the properties of fluid bed granulation products [19,22] are summarized below. These generalizations require experimental testing, however, for each spray granulation application. 

Newton (power) number, which relates the drag force acting on a unit area of the impeller and the inertial stress, represents a measure of power requirement to overcome friction in fluid flow in a sfirred reacfor. In mixer-granulation applications, this number can be calculated from the power consumption of the impeller or estimated from the power consumption of the motor. 

Sheskey P. et al. Foam technology the development of a novel technique for the delivery of aqueous binder systems in high-shear and fluid-hed wet-granulation applications, in Poster Presented at AAPS Annual Meeting and Exposition, Salt Lake City, UT, Oct. 2003 pp. 26-30. 

Conventional operation of a fluidized bed for food or particulate application mainly deals with the dehydration of water. Drying of pharmaceutics very often involves the dehydration of volatiles and organic solvents. This is partly due to the insolubility of most drug materials. Therefore, additional safety features have to be put in place in the operation of a fluidized bed for drug particle granulation applications. Such potential hazard is further enhanced by a dusty environment within a fluidized bed. 

Fig. 11.1 Varied requirements regarding structure and mechanical properties for varied granule applications...

Acidity or alkalinity PETN granulation applicable to pentolite manufactured by the coprecipitation method Through sieve number Percent, minimum Percent, maximum 100°C vacuum stability test... 

One more application area is composite materials where one wants to investigate the 3D structure and/or reaction to external influences. Fig.3a shows a shadow image of a block of composite material. It consists of an epoxy matrix with glass fibers. The reconstructed cross-sections, shown in Fig.3b, clearly show the fiber displacement inside the matrix. The sample can be loaded in situ to investigate the reaction of matrix and fibers to external strain. Also absorption and transmission by liquids can be visualized directly in three-dimensions. This method has been applied to the study of oil absorption in plastic granules and water collection inside artificial plant grounds. 

The stirring produces the end product in the desired divided-sohds form. Hence, it is frequently termed a granulator or a ciystaUizer. A variety of factoiy-made sizes in various materials of construction are available. Initial cost is modest, while operating cost is rather high (as is true of all batch devices), but the ability to process gummy burdens and/or simultaneously effect two unit operations often yields an economical application. 

The Andritz-Sprout-Bauer attrition miU (Fig. 20-51) is available in single- and double-runner models with 30- to 91-cm- (12- to 36-in.-) diameter disks and with power ranging up to 750 kW (1000 hp). By the use of a variety of plates and sheirconstruciions these units are represented in such applications as coarse granulating, piilveriz-ing, and shredding. 

Method Product size (mm) Granule density Scale of operation Additional comments Tyj)ical applications... 

Centrifugal granulators 0.3 to 3 Moderate to high Up to 200 kg hatch Powder layering and coating applications pharmaceuticals, agricultural chemicals... 

In the pharmaceutical industiy, pan granulators are still widely used for coating application. Pans are suitable for coating only relatively large granules or tablets. For smaller particles, the probability of coalescence is too high. 

Traditionally, active carbons are made in particulate form, either as powders (particle size < 100 pm, with an average diameter of -20 pm) or granules (particle size in the range 100 pm to several mm). The main precursor materials for particulate active carbons, PAC, are wood, coal, lignite, nutshells especially from coconuts, and peat. In 1985, 360 kt of such precursors (including 36 % wood and 28 % coal) were used to make active carbons [10], of which nearly 80 % were used in liquid-phase applications, with the rest being used in gas-phase applications. Important factors in the selection of a precursor material for an active carbon include availability and cost, carbon yield and inorganic (mainly mineral) matter content, and ease of activation. 

Zeolite Pellets or granules of aluminum silicate, used in water treatment or aircleaning applications. 

The application methods will be categorised by the physical form of the thermoplastic, e.g. liquid, powder, granule. 

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