DUOLINE duplex bag filter housings are for applications where the process flow cannot be interrupted for filter bag changing.  Flow is diverted using ball or butterfly valves individually or through a common linkage; it is also possible to have "push button" automation using valve actuators.  We wrote an article comparing ball valves to butterfly valves which might help you determine which design is best for your application.

 

The underlying bag filter vessel designs used for DOULINE duplex configurations are the TOPLINE, SIDELINE and FLOWLINE bag filter housing designs.  Each bag filter housing has specific features and advantages; for example if you have a <50 micron filtration application it is recommended to use a TOPLINE style housing due to the way the filter bag seals to the vessel.  To learn more about each bag filter housing style to help determine which is most appropriate for your application, refer to our article "How to select a bag filter housing".

 

To Link or Not to Link?

If the diverting valves are not linked together then they need to be operated in a specific order to ensure continuous flow.  Alternately the valves can be linked together to a single operator so that one movement controls all diverting valves to ensure diversion occurs correctly.  The linkage we provide is limited to DOULINE duplex strainers using butterfly valves for flow diversion, however there are applications involving extreme temperatures, pressures and high particulate loads which would benefit from ball valves.  Since most bag filter applications involve water-like fluids with pressures ≤ 285 PSIG at temperatures between -20ºF to 100ºF with ≤ 200 PPM particle concentration, butterfly valves are the most common configuration.  It is possible to automate the actuation of the diverting valves simultaneously to accomplish safe diversion using either ball or butterfly valve designs. 

 

Since the DOULINE duplexed bag filters are based upon our other standard bag filter designs you can increase the filtration surface area and thereby reduce filter bag replacement frequency by using a HAYFLOW style support basket and filter bag.  These are limited to nominal filtration ranges of 1 to 100 microns with the filter bag being made of either polypropylene or polyester felt material. 

 

Another consideration for continuous flow applications would be our automated filter systems, these eliminating filter bag change-outs altogether and instead backwash the particulate from a permanent stainless steel filter element.

 

DOULINE Duplex Bag Filter Catalog Pages

 

Outline Drawings

• DOULINE TOPLINE Style

• DOULINE SIDELINE Style

• DOULINE FLOWLINE Style