Fundamentals and Advantages of Screen Filtration
The “art” of filtration utilizes many methods for separating solid particles from fluids. There is often no right or wrong method. Water quality and customer requirements usually determine the “best” method for each unique situation. Ridged screens, pleated cartridges, string wound cartridges, melt blown cartridges, woven fabrics, non woven fabrics, sintered metals, granular media, frizzy balls and membranes are just some of the types of filters available today. This plethora of filter types are often employed to do the same thing - remove suspended solids from a stream of water. All aspects of the many types of filters available cannot be addressed in this forum. Therefore, this manuscript will concentrate on only screen filters and their properties. Aside from all the advantages of screen filtration, one of the biggest hindrances to their use is their tendency to clog quickly and need for frequent manual cleaning. There are many automatic and semiautomatic methods available to minimize or even eliminate the need for labor when cleaning the permanent screens in this class of filter. Screen filters can be stand-alone equipment or can be pretreatment for other methods of removing finer solids down to the size of ions. With openings as large as 2”, such as bar screens at wastewater treatment plants, to openings as small as 10 microns, screen filters can be used for a wide variety of applications when properly applied.