Duplex filters: Keep your process running
  • Continuous operation
  • Variety of filter elements
  • Double Block and Bleed technology
BOLLFILTER Duplex Filter

Duplex filters: Uninterrupted operations

Duplex filters are a valuable solution for applications where continuous fluid filtration is essential, and uninterrupted operations are crucial. They provide a balance between efficient filtration and minimal downtime by allowing for on-the-fly switching between two filter housings. This design ensures that the system remains operational even during maintenance or replacement of filter elements.

Are you searching for a duplex filter that perfectly suits your requirements? Our dedicated team is ready to assist you in selecting the ideal filter.

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BOLLFILTER Duplex Type BFD-C HD M
Coalescer gas filter for Heavy Duty »

BOLLFILTER Duplex Type BFD-C HD M
Features
Duplex filter for separating solids and aerosols (liquid content) from gases
Flange Connection
ASME or DIN ¾” – 8” or DN 20 – DN 200
Filter element
Fiberglass/stainless steel disposable cartridges (as normal temperature and high/low temperature design); Option available for preliminary separation using demister, cyclone, or cyclone demister all within the same housing.

BOLLFILTER Duplex Type BFD-C/P DBB M
Coalescer and particle gas filter with Double Block and Bleed »

BOLLFILTER Duplex Type BFD-C/P DBB M
Features
A special design duplex filter for separating solids and/or aerosols (liquid content) from gases using a patented double block and bleed main transfer valve. This is intended for applications using high pressures and/or dangerous gas compositions, to ensure maximum operator safety.
Flange Connection
ASME or DIN ¾” – 8” or DN 20 – DN 200
Filter element
- Fiberglass/stainless steel disposable cartridges - Option available for preliminary separation using demister, cyclone, or cyclone demister all within the same housing

BOLLFILTER Duplex Type BFD-P HD M
Particle gas filter for Heavy Duty »

BOLLFILTER Duplex Type BFD-P HD M
Flange Connection
ASME or DIN ¾” – 8” or DN 20 – DN 200
Filter element
Fiberglass/stainless steel disposable cartridges. Cleanable elements (star-pleated) made of stainless steel.
Grade of filtration
0,5 - 250 µm

BOLLFILTER Duplex Type BFD
Cast filter with ball changeover valve »

BOLLFILTER Duplex Type BFD
Flange Connection
ASME or DIN 1" - 6" / DN 25- DN 150
Switch-over
ball valve
Filter element
candle or basket element

BOLLFILTER Duplex Type 2.04.5
Nodular cast iron filter with plug changeover valve for small volumes »

BOLLFILTER Duplex Type 2.04.5
Flange Connection
DIN Only DN 25 - DN 80 (Approx. 1" - 3")
Switch-over
plug valve
Filter element
star-pleated element, basket element

BOLLFILTER Duplex Type 2.05.5
Filter with nodular cast iron housing and plug switch for large volumes »

BOLLFILTER Duplex Type 2.05.5
Flange Connection
DIN Only DN 100 - DN 250 (Approx. 4" - 10")
Switch-over
plug valve
Filter element
basket element, ring element, filter candle insert, multi-mantle element

BOLLFILTER Duplex Type 2.68.2 / 2.78.2
Welded filter with ball change over valve and flexible connections »

BOLLFILTER Duplex Type 2.68.2 / 2.78.2
Flange Connection
ASME or DIN 2 ½" - 16" DN 65 - DN 400
Switch-over
Ball valve Change over (optional as with Butterfly valves).
Filter element
- Cleanable (stainless steel element), - Disposable (glass-fiber matting)

Filtration phase

While one filter chamber of the duplex filter is in filtering mode, the other chamber is always with a cleaned filter element off line. The liquid passes through the filter element and over time the pressure drop in this filter chamber will increase. The increased pressure drop is an indication that particles have been accumulated and cleaning is required. Optional a differential pressure indicator can be installed on the duplex strainer.

Cleaning phase

By activating the switch plug, the clean filter chamber will be put in operation and the dirty filter chamber is simultaneously switched off. Switching to the clean filter chamber is carried out without a pressure surge.

For cleaning, the contaminated filter chamber is depressurized by the vent screw, the housing cover is
removed and the filter element has to be removed. The filter element is cleaned by flushing it with a cleaning fluid and subsequently blown out using compressed air.

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Advantages of BOLL Duplex strainers

BOLL Duplex filters offer several advantages tailored to ensure uninterrupted operation and enhanced safety in industrial processes:

Continuous Operation Assurance: With BOLLFILTER Duplex filters, your process can keep running seamlessly. The duplex design allows for continuous filtration even during maintenance or cleaning procedures. By switching between filter elements, one side remains operational while the other undergoes maintenance, ensuring uninterrupted production.

Variety of Filter Elements: BOLLFILTER Duplex filters offer a wide range of filter elements to accommodate diverse filtration needs. Whether your process requires fine filtration, coarse filtration, or specialized media for specific contaminants, BOLLFILTER provides various options to optimize filtration efficiency and performance.

Increased Safety: BOLLFILTER Duplex filters incorporate Double Block and Bleed (DBB) technology, enhancing safety during maintenance or element changeouts. DBB ensures that both inlet and outlet ports are sealed off simultaneously, isolating the filter chamber from the process flow. This feature prevents fluid bypass and minimizes the risk of contamination or leaks, enhancing operational safety.

Ensure uninterrupted operation!