Application equipment classification

Table 3.1 Application equipment classification (after Parkin et al., 1994) Aspect Possible descriptors...

The scope to alter both the efficiency and safety of application through control of the fate of applied material has been explored in a classification of application equipment by hazard (Parkin et al., 1994). Application techniques as well as equipment are required to be taken into account for such a classification, which covers all four possible distinct styles of application i.e. direct, liquid, solid and space. The direct style of application, which is typified by the need to bring treated items into intimate contact with pesticide, is exemplified by admixture processes, e.g. seed treatments. Direct applications take place under highly controllable conditions and often within relatively confined environments, which can potentially mitigate the exposure risks from applied material (presented either in... 

Parkin CS, AJ Gilbert, ESE Southcombe and CJ Marshall 1994. British Crop Protection Council Scheme for the classification of pesticide application equipment by hazard. Crop Protection 13(4), 281-285. 

Conveyor-Belt Devices The metal-belt type (Fig. 11. 55) is the only device in this classification of material-haudhug equipment that has had serious effort expended on it to adapt it to indirecl heat-transfer seiwice with divided solids. It features a lightweight construction of a large area with a thin metal wall. ludirect-coohiig applications have been made with poor thermal performance, as could be expected with a static layer. Auxihaiy plowlike mixing devices, which are considered an absolute necessity to secure any worthwhile results for this seiwice, restrict applications. 

Classification of screening operations and the range of separations that can be attained with various screens were given in concise form by Matthews (op. cit., 1971). See Table 19-5. Further details are given under Equipment. Figure 19-14 indicates the size-range applicability of various screen types. 

The above discussion leads to the conclusion that time-related and demand-related failures for a piece of equipment cannot be equated through a general mathematical relationship. These issues are better dealt with in a data base taxonomy (classification scheme) for equipment reliability data by defining a unique application through equipment description, service description, and failure description. 

Dyeing applications, tetrahydrofurfuryl alcohol in, 12 279 Dyeing theory, 26 394-395 Dyeing transition temperature, 9 159 Dye intermediates, 9 265-298 chemistry, 9 266-291 classification, 9 265-266 economic aspects, 9 293-295 equipment and manufacture, 9 291-293 health and safety factors, 9 295-298 obtained by nitration, 9 2 7 It obtained by sulfonation, 23 525 unit processes, 9 269-283 Dye lasers, 74 702-705 23 144 output characteristics of, 74 705 Dye-ligand affinity chromatography, 6 402 Dye liquor, 9 163 Dye manufacturing... 

Environment and health-related problems DCM is toxic for the central nervous system, for the liver and the kidneys (MAK-value 350 mg/m ), and it is absorbable via skin. Furthermore DCM is a suspected carcinogen (classification care, cat 3). DCM is low volatile and the vapour is heavier than air, thus high concentrations may occur at ground level during application. Activated-carbon-filters are ineffective and normal glove materials are penetrated within a few minutes. The required breathing equipment is, however, hardly used by craftsmen, which results in several deaths every year. 

There is a clear need for other size classifiers which combine a high separation efficiency with flexibility and compactness. Hydrocyclones have a small volume, are simple in operation and are standard size classification equipment, for example in closed circuit grinding applications. The recent development of the flat-bottom hydrocyclone, which permits classification in the coarse size range, creates an additional motive to study the use of hydrocyclones for Crystal Size Distribution (CSD) control. Furthermore, throttling of a flat botom hydrocyclone does not necessarily provoke blockage but allows continuous control of its cut size when a controlled throttling valve is used. There is a clear incentive for its use in this application since it may provide an additional process input. 

Equipment for extraction and leaching must be capable of providing intimate contact between two phases so as to effect transfer of solute between them and also of ultimately effecting a complete separation of the phases. For so general an operation, naturally a substantial variety of equipment has been devised. A very general classification of equipment, their main characteristics and industrial applications is in Table 14.2. A detailed table of comparisons and ratings of 20 kinds of equipment on 14 characteristics has been prepared by Pratt and Hanson (in Lo et al., 1983, p. 476). Some comparisons of required sizes and costs are in Table 14.3. 

Fine grinding and air classification make possible the production of some cake flour from hard wheat and some bread flour or high-protein fractions from soft wheat. Application of the process theoretically frees the miller from dependence on different wheats, either hard or soft, that change each crop year. The problem is how to market the larger volume of low protein or starch fractions at prices adequate to justify the installation and operation of the special equipment (46). 

Because of their important application value, much research and development on the preparation technologies of ultrafine powders has been carried out in the last twenty years and more, and hundreds of preparation methods have been proposed. Since they are not the major topic of this book, neither a description of the classification of the methods nor an introduction to the details of the various methods will be covered here. On the other hand, reaction-precipitation methods generally have a number of advantages such as lower cost, moderate operating conditions, lower equipment requirements, convenience of operation, and normally yield good-performing products etc. thus they occupy an important position among the various methods. 

There are no standard engineering classification methods for mixing equipment, and often, quite different types of mixers can fulfill the same mixing task. Nevertheless, we can subdivide mixers used in processing into three broad categories particulate solids mixers, laminar distributive mixers, and laminar dispersive mixers. This classification, on the basis of application, is supported by the nature of the primary mixing mechanism taking place in them. 

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