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Custom Fabricated Duplex Strainers

Model 950 custom fabricated duplex strainer

Custom fabricated duplex strainers are used when cast versions will not suffice.  Sometimes special alloys are required or there are other aspects of the application just not suitable for cast duplex strainers, so we custom fabricated a duplex strainer instead.

 

Fabricated duplex strainers consist of two fabricated basket strainers having their inlet and outlet located on the same side.  The two basket chambers are connected to an inlet and outlet pipe tee, having valves in-between.  One set of valve are closed, causing the flow to pass through the other chamber.  When it is time to clean the strainer basket, flow is diverted to the clean chamber and the dirty basket chamber is isolated so it can be safely accessed.  The connections to the pipeline are typically ANSI flanged although can also be butt weld or some other connection as required.

 

There is a specific order to manipulate the diverting valves to ensure the process flow is not interrupted.  First open the clean chamber discharge valve, then open the its inlet valve.  Next close the discharge valve for the dirty basket chamber and then close its inlet valve.  After venting the basket chamber and draining the fluid, the basket chamber can be safely accessed.

 

The type of valves used for custom fabricated duplex strainers is most commonly a butterfly valve, although ball valves can be used if required.   There are single, double and triple offset butterfly valves as well as 1, 2 and 3 piece ball valves; the valves used will depend upon the specific requirements of your application.  It is possible to use a pair of 3 way diverting ball valves that are linked together to accomplish a similar diversion, however it is  uncommon.

 

The baskets for large fabricated duplex strainers might require an overhead winch or lifting mechanism.  Optionally we can utilize a multiple basket design, so as an example, instead of using one large (heavy) basket, having four smaller baskets in the chamber - with each basket being easier to manually lift.

 

If your particle load is continuous and the pipeline 6" or larger, consider an automatic strainer which might cost the same or slightly less and provides the advantage of automatic operation without interruption of process flow.

 

For some applications we can supply a hinged "quick-opening" basket chamber cover design, which is especially useful for larger size strainers that would otherwise require a cover lifting davit assembly.

You can use our calculator above to approximate the 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 selecting 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.

 

Sometimes to attain the desired clean differential pressure a larger size strainer body is required, and since these are custom fabricated, attaching smaller connections to match your pipelines is not a problem.

 

Custom fabricated duplex strainers typically have a engineering and manufacturing lead time ranging from 6-12 weeks depending upon the degree of customization required and current shop load.

 

The part numbers for the Eaton (formerly Hayward) 150# class custom fabricated duplex strainers are listed below. Link to Custom Fabricated Duplex Strainer Catalog and IOM manual.

MAX. FLOW
(GPM)
CONNECTION
SIZE
COVER TYPE PART NUMBER
CARBON STEEL 316 SS
285 2" bolted ST952020BR3BA ST952020BR2BA
quick-opening ST952020BR3TA ST952020BR2TA
285 3" bolted ST952030BR3BA ST952030BR2BA
quick-opening ST952030BR3TA ST952030BR2TA
565 4" bolted ST952040BR3BA ST952040BR2BA
quick-opening ST952040BR3TA ST952040BR2TA
1,175 6" bolted ST952060BR3BA ST952060BR2BA
quick-opening ST952060BR3TA ST952060BR2TA
2,620 8" bolted ST952080BR3BA ST952080BR2BA
quick-opening ST952080BR3TA ST952080BR2TA
3,890 10" bolted ST952100BR3BA ST952100BR2BA
quick-opening ST952100BR3TA ST952100BR2TA
5,375 12" bolted ST952120BR3BA ST952120BR2BA
quick-opening ST952120BR3TA ST952120BR2TA
7,778 14" bolted ST952140BR3BA ST952140BR2BA
quick-opening ST952140BR3TA ST952140BR2TA
10,600 16" bolted ST952160BR3BA ST952160BR2BA
quick-opening ST952160BR3TA ST952160BR2TA
13,750 18" bolted ST952180BR3BA  
quick-opening ST952180BR3TA  
18,385 20" bolted ST952200BR3BA  
quick-opening ST952200BR3TA  
21,920 24" bolted ST952240BR3BA  
quick-opening ST952240BR3TA