Strainer basket A closed vessel with cleanable screen element designed to remove and retain foreign particles. Note the term "foreign particles". Basket 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. These strainers can be offered in Simplex , Duplex type depending on your process requirements. The Duplex strainers are offered with diverting valves. These strainers are offered with flush , drain connections with ball valves as the standard feature.