Backwashing

FILTERS AND STRAINERS DOE-HDBK-1018/2-93 Miscellaneous Mechanical Components Part C of Figure 24 shows a manifold steam strainer. This type of strainer is desirable where space is limited, because it eliminates the use of separate strainers and their fittings. The cover is located so that the strainer basket can be removed for cleaning. Backwashing Figure 24 Common Strainers If the filter or strainer cannot be easily removed for cleaning, the system design will usually include a flowpath for backwashing. The backwashing of precoated filters has already been explained because it is more complex than a typical backwash. The intent of a backwash is to flow liquid in the opposite direction of normal flow, creating a pressure that pushes the debris off the strainer or filter. The debris is flushed to a waste tank or drain. Normally, to establish a backwash lineup, the flowpath upstream of the inlet to the strainer or filter is closed, the flow path downstream of the outlet is closed, and a drain flowpath is opened. ME-05 Rev. 0 Page 46