There are many different styles of bag filter housings to choose from and
this article will help you determine which is the best fit for your application.
Simplex bag filter vessels require the flow rate to be interrupted or diverted to safely access the filter bag chamber(s).
Ecoline: Used for "light duty" applications and rated for a maximum pressure of only 100 PSI, the Ecoline has a clamp style closure and is only available in 316SS material with FNPT threaded connections. It does have some notable features, such as an investment cast concave chamber cover which displaces some fluid so that when the chamber is opened the fluid level is below the edge of the vessel. We can modify the vessel to have differential pressure ports, but that is about as much "customization" this design offers. The Ecoline cannot be ASME code stamped and filter bag sealing is assisted by a separate internal spool which transfers the downward pressure of the lid closure across the circumference of the filter bag. This type of sealing is characteristic of all our housing designs EXCEPT the Topline and therefore applications requiring high efficiency particle retention (greater than 65%) and especially for particle retention <50 microns, the Topline design should be utilized.
Miniline: A version of the Ecoline above designed to be used with smaller size filter bags (#3 and #4 sizes). Reserved for low flow rate applications when a compact size/footprint is desired, they are not much different in cost from the "full size" (#1 and #2 size) Ecoline and Flowline II bag filter housings.
Flowline II: This is an inexpensive version of the
Flowline
housing design, having some additional material options compared to
the Ecoline (carbon steel, 304SS and 316SS), Flowline II vessels are
rated to 150 PSI due to its swing bolt closure and are offered with
flanged or threaded connections. Their body is hydroformed,
reducing the number of weld areas, promoting a smoother internal
finish. While the manufacturing process reduces the cost of
the Flowline II, it also means that customizations such as adding
differential pressure taps, surface polishing and non-standard
connections are not available. As with the Ecoline above, this
entry-level housing is designed for nominally rated filter bag
applications where an ASME code stamp is not required.
Flowline: This is the entry-level housing for industrial applications that do not require an ASME code stamp. Since the manufacturing technique involves additional welding, its more expensive than the Flowline II but it also enables non-standard connection types, differential pressure taps and surface polishing.
Sideline: These filter bag housings can be customized more than the above, to include features such as steam jacketing, side outlet location and can be ASME UM or U stamped; CRN registration is also supported with this design. Features such as a concave displacement cover and a hold down spool are standard and similar to the other designs mentioned above.
Topline: Featuring a "goose neck" or "over-the-top"
inlet design, the Topline style housing represents the best sealing
capability of all bag filter housing designs. This is because
a hold-down spool is not required to seal the filter bag to the
vessel, rather the chamber cover directly interfaces with the bag
sealing ring and forms a bypass-free seal. This type of direct
seal with the filter bag is only possible with this inlet
configuration as it enables the filter bag to be placed at the top
rim of the vessel. The additional complexity of this
design contributes to its higher cost, but for applications
requiring efficient retention of particles smaller than 50 microns,
it is the best design to use. This ASME code
stamped vessel can be polished internally or externally as well as customized with
special connections, a steam jacket or differential pressure
connections.
Polyline and FLV: Represent our non-alloy designs (PVC, CPVC and PVDF). These are typically used for non-alloy pipelines and thus have some limitations; they cannot be ASME code stamped, polished or steam jacketed and their flow rates are typically limited to a maximum of 100 GPM. These are more expensive than their alloy counterparts and chosen for aggressive chemistries which otherwise would require expensive, "exotic" alloys.
All of the bag filter vessels above are single chamber, simplex designs. Therefore the flow rate is limited to the capacity of the single filter bag used within it and the process needs to be interrupted to change-out the filter bag.
To accommodate flow rates above 180 GPM, using specialty filter bags having a reduced flow capacity or for viscous fluids, using multiple chambers (filter bags) simultaneously is required.
MULTIPLE CHAMBER DESIGNS
Douline: Consist of two bag filter housings connected
by a common inlet and outlet manifold and thus having double the
capacity of a single chamber design; there are no valves to divert
flow, flow passes through both chambers simultaneously.
Within the 3, 4, 6 and 8 chamber range there are several design options
offered.
COVER DESIGN
Counter weighted spring assisted hinged covers can be opened and closed
safely by a single individual. This fantastic feature costs about 10% more
when compared to the lifting davit style, justified with its reduced footprint
and improved ergonomics.
While swing bolts provide relatively quick access to the filter vessel,
access is further improved with a gear operated clamp closure which ensures
positive and equal sealing across the chamber cover sealing area.
COVER
SEAL
ECONOMY MODELS
ALTERNATIVE DESIGNS: MODULINE
An
advantage of this approach is that, when properly sized, individual housings can
be isolated and filter bags replaced without needing to shut down or “duplex”
the system and thus can significantly reduce initial costs.
The filter housings can be oriented on both sides of an inlet/outlet header to
shorten its length and if you extend these headers, it will enable adding
additional filter stations in the future.
When your process cannot be interrupted to change filter bags and you are not
using the Moduline configuration above, we can supply a pair of simplex housings
connected by a common manifold having diverting valves to isolate the chamber to
be serviced.
Flow Rate (chamber size and number of chambers required)
The size of the bag filter vessel (number of filter bag chambers) depends upon the diameter and length of the filter bags required for your specific application. The four "industry standard" filter bag sizes are referred to as being #1, #2, #3 or #4 sizes, with #1 and #2 sizes being the most common for industrial applications.
When you complete our inquiry form
or otherwise contact us by email or phone, our filtration experts will
gather information about the filter bag aspect of your application to ensure
the most appropriate bag filter housing is suggested. Our filter bag website
provides detailed information and specification sheets for a variety of
filter bag types, complementing our filter bag housing website.