Our cast iron duplex strainers for ¾" to 24" size pipelines are listed below. All flanged connections are ANSI class 125#. Some of the Eaton duplex strainers are available in 150# class ductile iron material. You will note that the diverting method differs by strainer size.
Eaton, Keckley and Titan all offer a ball valve style diverter for the ¾" through 4" sizes; actually Keckley and Titan also offer this design for the 6" and 8" sizes. This is the simplest style diverter to use, the operator only needs to rotate the lever 180º to isolate a basket chamber. The Eaton and Titan designs have a soft valve seat, enabling better sealing than the Keckley style.
The 5" - 8" sizes for Eaton use a tapered plug valve style diverter. This requires an extra step, lifting the valve off its seat with a jack screw before the flow can be diverted. Having a metal-to-metal seal, the Eaton Model 50 Duplex Basket Strainer might be better suited for aggressive fluids.
Larger size duplex basket strainers utilize either linked butterfly valves or sliding disc valve designs. Eaton and Keckley offer the sliding disc valve style, Eaton from 8" to 24" sizes and Keckley from 10" to 20" sizes. Rotating a gear operator progressively slides the linked valves to the chamber to isolate.
The linked butterfly valve Eaton Model 52 Duplex Basket Strainers are offered in 10" - 18" sizes and are generally less expensive than the sliding disc style duplex basket strainers. Four butterfly valves are linked to a common gear operator to isolate one chamber while the other is opened.
The differential pressure calculator is valid for Eaton, Titan and Keckley, although some sizes have several different diverting style options (like 8"), so for the larger size strainers its a good idea to contact us and we'll compare your options if clean differential pressure or maximizing flow capacity are concerns.
Calculate the approximate clean differential pressure drop by selecting the strainer connection size, inputting your flow rate (GPM), inputting the specific gravity if other than water (sg of water = 1) and select the viscosity range if other than water (SSU of water = 30). Click "Update" to refresh the data and be sure that the clean differential is ≤2 PSI for the intended basket retention.
We wrote an article entitled BASKET STRAINERS: Differences between Simplex and Duplex Style Strainers which helps you decide if a duplex strainer is the best style for your application.