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

Duplex filters: Continous operations

Duplex filters enable efficient filtration and minimal downtime as they have two filter housings that can be used alternately. This design ensures continuous operation of the system even during maintenance or replacement of filter elements. Duplex filters are used in applications where continuous liquid filtration is essential and continuous operation is critical. 

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
DN 25 to DN 150
Switch-over
Ball valve
Filter element
Star pleated element Basket element Filter cartridges Disposable filter cartridges

BOLLFILTER Duplex Type 2.04.5
Duplex filter with cast housing and plug changeover for small volume flows »

BOLLFILTER Duplex Type 2.04.5
Flange Connection
Spheroidal graphite cast iron DN25 - DN80 Cast stainless steel DN25, DN32, DN50
Switch-over
Plug changeover valve
Filter element
Star-pleated element Basket element

BOLLFILTER Duplex Type 2.05.5
Double filter with spheroidal graphite cast iron housing and plug switchover for large volume flows »

BOLLFILTER Duplex Type 2.05.5
Flange Connection
DN 100 to DN 250
Switch-over
Plug changeover valve
Filter element
Basket strainer Candle insert

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
DN 65 to DN 400 Other nominal sizes on request
Switch-over
Up to DN 150 ball valve changeover from DN200 with damper control
Filter element
Basket strainer Star sieve Disposable filter cartridge Candle insert

Filtration phase

While one filter unit of the Duplex filter is in operation for liquid filtration, the other filter chamber is always cleaned in reserve. If the tolerance limit of the clogging indicator is set, it indicates the pressure loss based on the degree of clogging. The tolerance limit can be specified in advance according to the requirements. 

Switching over the Duplex filter

The clean filter chamber of the liquid filter in reserve is put into operation by pressing the switchover button. At the same time, the filter chamber that was previously in operation is taken out of operation. The switchover to the cleaned filter unit takes place without pressure surges.

Cleaning phase

Duplex filters are easy to maintain. Before you start the cleaning process, the dirty filter chamber must be depressurized and the housing cover removed. The filter element can then be easily removed, rinsed with a cleaning fluid and thoroughly cleaned of dirt using compressed air or the optionally available ultrasonic cleaning device.

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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.

Variety of Filter Elements: BOLLFILTER Duplex filters offer a wide range of filter elements and meet the most diverse filtration requirements. Whether your process requires fine or coarse filtration or special media for specific contaminants, BOLLFILTERs offer various options to optimize the efficiency and performance of the filtration solution.

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!