4 - Industrial Filtration Equipment

Abstract

Filtration equipment is commercially available in a wide range. Proper selection should be based on detailed information of the slurry to be handled, cake properties, anticipated capacities, and process operating conditions. One may then select the preferred operational mode, and choose a particular system on the above considerations and economic constraints. Continuous filters are composed of essentially a large number of elemental surfaces on which different operations are performed. These operations performed in series are solids separation and cake formation, cake washing, cake dewatering and drying, cake removal, and filter media washing. The specific equipment used can be classified into two groups: stationary components, and scraping mechanisms and movable devices. Either continuous or batch filters can be employed in cake filtration. In filter medium filtration, where particulates are retained within the framework of the filter medium, batch systems are most common. Batch filters may be operated in any filtration regime, whereas continuous filters are most often operated under constant pressure. To organize a number of different types of filtration equipment, two classification schemes have evolved for continuous operations. The first scheme is based on operating pressure differentials, while the second scheme is based on the relative difference between gravity force and filtrate motion. Three orientations are possible: forces acting in opposite direction, forces acting in the same direction, and forces acting normal or perpendicular to each other. Because the influence of gravity is so important to most filtration operations, the second classification basis is used in the chapter. The operating principles and important features of filtration equipment are described in the chapter with the intent of providing the reader a background of the versatility and selection options available.