A CLOSED VESSEL WITH CLEANABLE SCREEN ELEMENT DESIGNED TO REMOVE AND RETAIN FOREIGN PARTICLES DOWN TO 0.001 INCH DIAMETER FROM VARIOUS FLOWING FLUIDS." Note the term "foreign particles". Strainers do not necessarily remove only dirt. They take out material which is not wanted in the fluid and this can sometime be a valuable product which may be saved. Basket strainers are designed for installation in horizontal lines. They are commonly used for liquid service applications. Basket Strainers are generally used where high flow capacity is required. The basket Strainer is serviced by removing the cover, which yields access to the basket. Basket Strainers are also available in a duplex style which consists of two parallel basket Strainers and diverting valves, which permit diversion of the flow through one of the Strainer elements while the other element is being serviced-an essential feature where flow cannot be interrupted.