DuoFLO™ Filter Systems

The patented 3M CUNO DuoFLO™ filter system* is an advanced alternative to standard bag filters. Developed using CUNO's extensive depth filtration experience, the DuoFLO filter media, featuring a true graded-porosity structure, is now available to users of standard bag type filters and housings. This feature, combined with a 62 % increase in filter surface area, ensures that DuoFLO filters provide:

  • up to 4 times or more the service life of conventional felt filter bags
  • superior contaminant removal efficiency
  • enhanced flow per filter element
  • reduced total filtration costs by minimizing production downtime, disposal and labor costs.

Materials of Construction

Each grade of DuoFLO filter is manufactured from high performance fibres that were selected based on extensive media performance testing. No adhesives, binders, or silicone are used in the manufacturing process. The DuoFLO filter element is available in all-polypropylene, all-polyester, or polyester media with polypropylene lower seal and top plate construction.

Filter Element Size and Ratings Available

DuoFLO elements are available in sizes and ratings to replace standard #1 and #2 filter bags as follows:

DuoFLO Filter Element Specifications
Dimension DuoFLO Elements
#1 Size #2 Size
Nominal Removal Ratings (microns) 1, 5, 10, 25, 50, and 100
Filter Diameter (inches/cm) 7 / 17.8
Filter Length (inches/cm) 14.3 / 36.3 28.6 / 72.6
Media Area (ft2 / m2) 3.4 / 0.32 6.7 / 0.62
Hold Up Volume per Filter (Gallons / Litres) 0.7 / 2.6 1.4 / 5.3
Operating Parameters by Material and Size
Operating conditions DuoFLO DuoFLO
Polypropylene Polyester
#1 Size #2 Size #1 Size #2 Size
Maximum Operating Temperature (°F / °C) 180 / 82 300 / 149
Maximum Recommended Flow Rate (gpm / lpm) 75 / 284 150 / 568 75 / 284 150 / 568
Maximum Forward Differential Pressure 35 psid @ 68°F (2.4 bar @ 20°C)
Recommended Change-out Differential Pressure 20 psid (1.4 bar)
Regulatory Status (Polypropylene elements only)
CFR Compliant All component materials of the DuoFLO all-polypropylene element are listed for food contact per 21 CFR 177.1520.


  • Unique filter design combining a graded-porosity media with 62% greater filter surface area
  • Hold-up volume reduced by 67% compared to conventional bag filters.
  • 100%, downstream support of the filter element
  • Superior flow characteristics


  • Longer Service Life – up to 4 times or more that of conventional felt filter bags
  • Reduced Filter Usage - minimizes product loss, labor, disposal costs, and operator exposure
  • Less down time for filter change-out increases productivity
  • Reduced product loss & related disposal costs
  • Used element retains less fluid making it lightweight for easy removal
  • Eliminates the need for displacement balloons and associated spillage during change-out
  • Eliminates filter rupture, contaminant bypass and unloading
  • Allows operation to higher differential pressures before filter change-out
  • Maximizes utilization of filter surface area and maintains low operating pressure drop
  • Reduces flow per unit area for improved effluent quality

Flow Characteristics

Flow Characteristics

*#2 Size Element and Support Basket Pressure Drop Only, 4 housing pressure losses are not included.

RR Retention Rating
MT Maximum temperature recommended of a working product in degrees centigrade
MoC Primary material of construction
MoC Primary material of construction
MP Maximum working pressure of housing in bar
Brand Manufacturing brand name supplying the product
FE Filter efficiency
Q Quality assurances and certificates validating this product