Bag Filter Housings made of PVC, CPVC and GFPP

Plastic bag filter housings are typically used for applications requiring the removal of very fine particles, in the 1 to 100 micron range. We offer plastic bag filter housings which are compatible with industry standard #1 and #2 size filter bags which have a 7” diameter opening and a filter bag length of 17" (#1) or 32" (#2).

Although filter bags are available with coarse retentions (up to 800 microns), it is more common to use pipeline strainers with either perforated or mesh lined baskets for those application unless the volume of particulate to be retained or materials of construction lend themselves to a bag filter housing design due to their a larger straining element and can be supplied in 100% non-alloy materials.

The Platinum Glass-Filled Polypropylene (GFPP) model is a one-piece molded vessel having numerous locations for true-union connections; these connections can also be made from GFPP, PVC or CPVC.  The sizes (from 1¼" to 4") and the connection types (FNPT/threaded, flanged and socket) are available in all materials.  "Glass Filled" polypropylene contain glass fibers which increases stiffness and surface hardness, thus supporting use at higher pressures and temperatures when compared to "regular" polypropylene.

The PVC and CPVC versions consist of a common upper and lower half, with a "spacer pipe" inserted between these two pieces to form the "body", thus  a longer pipe is used for the #2 size and a shorter one for the #1 size; the end connection material matches the body material.

Similar to the SB/DB styles of plastic pipeline strainers, the FLV has a thoughtful, user-friendly design.  It's "rabbit ear" style chamber cover enables quick removal and access to the filter bag within without requiring tools.  This style cover also reduces the potential for over tightening.  The bodies buttress style threads for the chamber cover provide a downwards oriented failure path, so in the event of over-pressurization the failure mode should be predictable and protect other system components from damage.  The chamber cover also has a conical shaped displacement geometry which serves two purposes, it reduces the volume of the chamber when accessing the filter bags and helps seal the filter bag in-place via downwards pressure onto the filter bag sealing ring.  The included vent port valve is easily opened to bleed air from the system during filling.

Whether GFPP, PVC or CPVC, the body has two inlet ports and two outlet ports to provide flexibility for installation.  Thus they can be installed inline (inlet and outlet are 180° apart - directly opposite of each other with high port the inlet and the low one the outlet) or "offline" using the upper and lower ports on the same side of the vessel.  As an example, the "offline" configuration is useful if installed in a corner. The GFPP material has additional ports at 90°, adding another potential inlet/outlet flow path.  Unused ports are capped-off with blank true-union connections. 

The true-union connection design simplifies installation as well as enabling filter housing replacement without cutting and replacing piping; perhaps especially useful for socket glued piping connections.

restrainer basketThere is a restrainer basket within the filter bag housing whose purpose is to support the filter bag, without support clogged filter bags might rip apart due to the weight of retained material. The o-ring seal ensures no fluid bypasses the filter bag. There are two configurations for the restrainer basket, one is simply a cylindrical basket and the other has a "clamshell" design, enabling the user to split the basket open, which is helpful removing very full filter bags and for installing new bags, especially the #2 size which are a little longer than most arms and insertion can be done without placing your hand/arm into the vessel which might contain an aggressive process fluid.  The restrainer baskets are made from the same material as the housing and can also be provided in 316SS for higher differential pressure applications characteristic of viscous fluids and high percentages of solids.

The only elastomers used are captured o-rings for the chamber cover, restrainer basket, true-union connections and o-rings for the vent valve; the o-ring materials are either EPDM or FKM.

Other significant aspects to consider include:
Never use plastic bag filters for compressible fluids such as air or nitrogen.
• The maximum flow rate per housing is 100 GPM for single length (#1 size) and 150 GPM for double length (#2 size).

• Your piping system should be independently supported; the filer housing is not designed to support piping nor should piping support the filter housing.  The filter housing should be mounted to a firm surface and the piping upstream and downstream of the strainer should be independently supported.
• It is critical to review your pressure limitations for your fluid temperature and reduce the potential for a Water Hammer situation accordingly.

When in-doubt, simply call us or better yet, fill-out our application based inquiry form and we'll assist you with the proper selection.