Duplex Strainer
Twin-basket design allowing continuous operation during cleaning and maintenance.
Technical Specifications
| Type | Duplex (Twin Basket) |
| Size Range | 2" to 16" (50 mm to 400 mm) |
| Body Materials | Carbon Steel, Stainless Steel |
| Screen Material | SS304 / SS316 |
| Mesh Size | 20 to 200 mesh (customizable) |
| End Connections | Flanged |
| Pressure Rating | PN16, Class 150 |
| Standards | ASME B16.34 |
Applications
Continuous operation, fuel systems, critical processes
About the Duplex Strainer
The duplex strainer houses two independent basket filter chambers side by side, connected to the inlet and outlet pipe through a 3-way diverter valve (or twin-plug configuration) that can switch the full flow from one basket to the other with a single valve rotation. When one basket becomes fouled and the differential pressure across it rises to a set threshold, the operator switches the diverter valve to route flow through the clean basket - a process that takes less than 60 seconds and causes no interruption to the process. The fouled basket is then isolated, the cover is opened, the dirty basket is removed and cleaned, and the basket is reinstalled ready for the next switching cycle.
This continuous-operation, switchable filtration capability makes duplex strainers mandatory on fuel oil systems (where uninterrupted fuel supply to boilers or engines is critical), critical process pump suction lines that cannot be shut down without production loss, and ship and offshore platform systems where sea voyage conditions prevent planned maintenance shutdowns. The changeover under flow means there is no differential pressure spike across the switching event - unlike simplex strainers where pressure rises until the line is shut down and the basket is cleaned. Vajra Industrial Solutions supplies duplex strainers in sizes 2" to 16" in Carbon Steel and SS316 with SS316 screens, diverter valve, and DP gauge connections to ASME B16.34.
Where It's Used
Key industries and applications for the Duplex Strainer
Fuel oil supply to boilers and industrial burners
Carbon Steel duplex strainers on fuel oil supply headers; uninterrupted fuel supply during basket changeover is critical to boiler flame stability and plant energy supply
Marine diesel engines and offshore platform generators
compact SS316 duplex strainers on HFO (heavy fuel oil), MDO (marine diesel oil), and lubricating oil supply to main propulsion engines and generators; SOLAS requires no interruption to engine fuel supply
Critical process pump suction
SS316 duplex strainers on process pump suction in refinery, chemical, and pharmaceutical continuous processes; switching capability allows basket cleaning without pump shutdown and without process interruption
Hydraulic power unit (HPU) suction filtration
duplex strainers on HPU reservoir suction to hydraulic systems serving subsea wellhead control and platform crane hydraulics; continuous clean fluid supply protects high-value hydraulic components
Cooling water supply to critical heat exchangers
Carbon Steel or SS316 duplex strainers on cooling water supply to reactor jacket, compressor lube oil coolers, and turbine oil coolers; prevents debris from fouling critical cooling circuits that cannot be isolated
How to Choose the Right Duplex Strainer
Specify a duplex strainer wherever the process cannot tolerate a shutdown for basket cleaning - continuous fuel systems, uninterruptible pump suction, and critical cooling circuits. For less critical applications where planned shutdown for basket cleaning is acceptable, a simplex basket strainer is less expensive. Size the duplex strainer so each basket chamber can handle 100% of design flow (both baskets are sized for full duty, not 50% each). Install a differential pressure gauge or switch across the strainer to trigger basket changeover at the defined fouling pressure drop.
Popular Configurations
Most commonly ordered specifications for the Duplex Strainer
Frequently Asked Questions
About Duplex Strainer - ordering, specs, delivery & compliance
What standards does the Duplex Strainer comply with?+
Our Duplex Strainer complies with ASME B16.34. All products are manufactured to international standards and come with full material test reports (MTR), dimensional inspection reports, and hydrostatic test certificates on request.
What materials are available for the Duplex Strainer?+
The Duplex Strainer is available in Carbon Steel, Stainless Steel. Material selection depends on your process fluid, temperature, pressure, and corrosion requirements.
What is the delivery lead time for Duplex Strainer?+
Standard stock sizes are available for immediate dispatch from our Vadodara warehouse. Custom sizes and special materials typically have a lead time of 2–6 weeks depending on specifications. We serve customers across India within 1–7 business days and export to the Middle East, Southeast Asia, Europe, and the Americas with full export documentation.
Can I get a custom Duplex Strainer for a specific application?+
Yes. Vajra Industrial Solutions supplies custom-engineered strainers for specific process conditions. Submit your technical requirements - including pressure class, temperature range, fluid type, end connections, and any special trim or coating needs - via our RFQ form or WhatsApp, and our engineering team will respond within 24 hours.
What pressure ratings are available for the Duplex Strainer?+
The Duplex Strainer is available in pressure ratings of PN16, Class 150. Higher-pressure classes are available for critical service applications in oil & gas, power generation, and chemical processing.
How do I request a quote for the Duplex Strainer?+
You can request a quote by clicking the "Request Quote" button on this page, filling out our RFQ form at vajravyuh.com/rfq, emailing us at sales@vajravyuh.com, or WhatsApping us directly at +91-9979774557. Please include quantity, size, pressure class, material grade, and end-connection type for the fastest response.
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