Duplex Basket Strainers
Two filter chambers and a changeover valve, so the line never stops. Clean or replace one basket while the other carries the flow.
Duplex Basket Strainer 316SS fitted with 3 way fla
Duplex Basket Strainer 316SS fitted with 3 way fla
Duplex Basket Strainer 316SS fitted with SS butter
Duplex Basket Strainer 316SS fitted with SS butter
Duplex Basket Strainer Carbon Steel fitted with DI
Duplex Basket Strainer Carbon Steel fitted with DI
About Duplex Basket Strainers
A duplex basket strainer is two basket strainers in one body with a changeover valve between them. Flow runs through one chamber while the other sits isolated, so you can open the standby chamber, lift out the basket, clean it and put it back without stopping the line. Where a shutdown to clean a simplex strainer costs more than the strainer does, a duplex pays for itself the first time you use it.
When continuous flow is worth paying for
The case for a duplex strainer is not technical, it is operational. Work out what an hour of stopped flow actually costs on that line: lost production, a plant restart, a tanker waiting, a treatment process out of specification. If that number is meaningful and the strainer needs cleaning regularly, a duplex is the cheaper answer even though the unit costs more.
It is also the right choice where the debris load is unpredictable. A simplex strainer on a line that occasionally gets a slug of debris means an unplanned shutdown at the worst possible moment. A duplex turns that into a changeover.
Changeover valve options
Two arrangements are common. A three-way plug or ball valve gives you a single-lever changeover, which is quick and hard to get wrong, and suits smaller and medium line sizes. Paired butterfly valves are used on larger sizes where a three-way valve becomes impractical, and give you the option of overlapping the changeover so flow is never interrupted at all.
Both arrangements let each basket be removed independently through its own top cover, so maintenance stays a quick job rather than a pipework exercise.
Materials, ratings and service life
316 stainless steel is the standard for water and wastewater service and is what we supply most often. Carbon steel is available where the specification calls for it and the media is non-corrosive. Pressure ratings supplied are PN10, PN16 and PN20 (ANSI Class 150), flanged to AS4087 Table D or Table E, or ANSI 150lb.
As with every strainer, maximum allowable working pressure falls as fluid temperature rises, and the limiting component is usually the seal and gasket material rather than the body. For service life, passivation after fabrication and internal coatings such as PTFE are both available, and material certificates can be supplied with the unit.
Applications
Key Features
- ✓Continuous filtration, no shutdown to clean
- ✓Three-way valve or paired butterfly valve changeover
- ✓316 stainless steel standard, carbon steel to order
- ✓Independent top-access covers on each chamber
- ✓PN10, PN16 and PN20 (ANSI Class 150)
- ✓0.5mm to 3mm screen openings, custom mesh to order
- ✓Passivation and PTFE internal coating options
Duplex Basket Strainers Specifications
| Body material | 316 stainless steel standard, carbon steel to order |
|---|---|
| Changeover | Three-way plug or ball valve, or paired butterfly valves |
| Pressure ratings supplied | PN10, PN16 and PN20 (ANSI Class 150) |
| Flange standards | AS4087 Table D and Table E, ANSI 150lb, PN16 |
| Screen element | Perforated plate or mesh, 0.5mm to 3mm standard openings |
| Surface treatment options | Passivation, PTFE and other internal coatings |
| Documentation | Material certificates available on request |
Maximum allowable working pressure reduces as fluid temperature rises. Give us your operating temperature along with your pressure and we will confirm the correct rating and seal material for the duty.
Who selects these strainers
Kris McKeown, Director, Dewater Products. Over 12 years as a Mechanical Engineering Technician and more than 17 years in industrial sales. Kris selects and specifies every strainer Dewater supplies.
Dewater Products has supplied industrial fluid piping products Australia-wide from Perth since 2015, sourcing from over 20 approved manufacturers across 5 countries. If you are not sure which strainer suits your duty, call 1300 271 290 and talk it through before you order.
Duplex Basket Strainers FAQs
How do you clean a duplex strainer without stopping flow?
You operate the changeover valve to divert flow to the standby chamber, isolate the chamber you want to service, open its top cover, lift the basket out, clean it and put it back. The line keeps running throughout. With paired butterfly valves you can overlap the changeover so there is no interruption to flow at all.
Three-way valve or butterfly valves?
A three-way plug or ball valve gives a single-lever changeover that is quick and hard to get wrong, and suits smaller and medium sizes. Paired butterfly valves are used on larger lines where a three-way valve becomes impractical, and allow an overlapping changeover.
Is a duplex strainer worth the extra cost over a simplex?
It depends on what a shutdown costs you. Work out the cost of an hour of stopped flow on that line and compare it with the price difference. If cleaning is frequent, or the debris load is unpredictable enough that an unplanned stop is likely, the duplex is usually the cheaper option over the life of the installation.
Can you supply duplex strainers in carbon steel?
Yes. 316 stainless steel is our standard and what we recommend for water and wastewater service, but carbon steel is available where the project specification calls for it and the media is non-corrosive.