Duplex Strainers are designed for applications where flow cannot be shut down to service the strainer screen. Change over is accomplished by use of butterfly valves. They are very economical because they are fabricated to your specific requirements and with your choice of valves. This arrangement provides a bubble-tight shut off between basket chambers, essential for use in negative head pump suction systems. Read more about Duplex StrainersThey are very economical because they are fabricated to your specific requirements and with your choice of valves.