Duplex strainers provide uninterrupted filtration by using two basket chambers with a diverter valve, flow passes through one basket while the other can be isolated, cleaned, and re-installed. This eliminates the need to shut down the system for strainer maintenance.
AQ Process Systems sources and exports manual duplex strainers (operator switches the diverter), semi-automatic (DP-triggered alarm prompts manual switching), and fully automatic (DP-actuated diverter switches automatically). Available in sizes from 1" to 24" in cast and fabricated construction.
Duplex strainers are essential for continuous-process systems, fuel supply to boilers and engines, lube oil systems, cooling water circuits, and any application where flow interruption is unacceptable.
| Product | Specification | Description |
|---|---|---|
| Manual Duplex | ||
| Manual Duplex Basket Strainers | 1", 24" | Class 150-600 | Flanged | Twin-basket strainers with manual diverter valve, operator switches flow between baskets for cleaning. |
| Automatic Duplex | ||
| Automatic Duplex Strainers | 2", 16" | DP-actuated | Pneumatic or electric | Automatic-switching duplex strainers, differential pressure across the active basket triggers automatic changeover to the clean basket. |
| Self-Cleaning Duplex Strainers | With backwash | Minimal manual intervention | Self-cleaning duplex strainers with automatic backwash of the offline basket, the dirty basket is cleaned and ready for the next switch. |
| Specialty | ||
| High-Pressure Duplex Strainers | Class 600-2500 | Forged body | High-pressure duplex strainers for HP steam, boiler feedwater, and high-pressure process applications, forged body construction. |
| Duplex Fuel Oil Strainers | Heated body | For heavy fuel oil (HFO) | Heated duplex strainers for heavy fuel oil, steam or electric jacket maintains oil temperature to prevent wax crystallisation on the screen. |
Duplex strainers allow basket cleaning without stopping flow, essential for continuous processes, boiler fuel supply, lube oil systems, and any system that cannot be interrupted. Simplex strainers require system shutdown for cleaning. If your process can tolerate brief shutdowns, a simplex strainer is simpler and more economical.
The diverter valve (typically a plug valve or ball valve mechanism) has three positions: flow through basket A, flow through basket B, and briefly both (during changeover). The operator or automated system rotates the valve from one position to the other, seamlessly switching flow to the clean basket while isolating the dirty basket for cleaning.
Automatic duplex strainers use differential pressure (DP) measurement across the active basket. As debris accumulates, DP increases. When DP reaches the set threshold, the system automatically switches flow to the clean basket and may initiate a backwash cycle on the dirty basket. Alarm outputs alert operators to clean the offline basket.
Yes. Duplex strainers for viscous fluids (heavy fuel oil, bitumen, molasses) are available with steam or electric heating jackets maintaining fluid temperature and viscosity through the strainer. Heated baskets prevent wax, paraffin, or solidified material from blocking the screen mesh.
Regular basket cleaning (frequency depends on debris level, may be daily, weekly, or monthly), periodic inspection of the diverter valve seals, and replacement of basket screens when damaged or corroded. The diverter valve mechanism should be operated regularly even if not required, to prevent seizing from disuse.
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