11th Oct 2022

What is a bag filter housing? How does it work?

Bag filters are convenient, simple to operate filter system and are favoured in many industries. But to have perfect filtration performance, you must match your filter bag with suitable bag filter housings.

Curious about how a bag filter housing operates? Let us explain...

Designed for optimum filtration performance, bag filter consists of:

  • A filter vessel (the pressure vessel)
  • A replaceable filter bag
  • An internal cage to support the bag
  • Sealing arrangements to access the bag
  • Process connections

Our bag filter housings are commonly made of stainless steel. Inside, the bag filters can be made of polypropene, polyamide (nylon) needlefelt, nylon monofilament mesh and melt-blown polypropylene fibres for the finer grades.

How does a bag filter housing work?

Fluid enters the housing and flows from the inside to the outside of the bag. The bag itself is supported by a perforated basket, and it's this that retains the differential pressure that builds as the filter operates and blocks the bag with contamination.

When they need replacing, the bags are accessed through the top of the housing. There are several types of closing mechanisms for easy access, matched to the process and fluid to be filtered.

See an example of bag filter housing in action:

HubSpot Video


There are two common types of bag filter housings. They vary by flow direction and how many filter bags they can house.

Side Entry bag filter housing

Side Entry bag filter housings are efficient and economical. Most commonly seen in the single bag housing size, these robust housings offer an optimised flow rate for small-scale filtration processes.

Top Entry bag filter housing

Top Entry bag filter housing offers the optimum flow path for the fluid, lowest fluid hold up and easiest access to the bags for changeout. Used with single and multi-bag housing, they're very common where the fluid is hot, viscous, or aggressive. With this style, the bag sealing mechanism is also more efficient.

Features of superior bag filter housings

  • Flexible sizes that fit the flow
  • Simple changeout
  • Easy to clean
  • Optimal construction

Simple to changeout

Bag filter housings are relatively easy to operate, however, there are applications where an inclined bag filter housing would make it easier for operators to extract the filter bag. Hydraulic lids can be added to larger housings to eliminate the heavy manual handling that larger housings can pose.

Bag filter housings can be designed to work alongside contained filter systems, too. These secure the filter assembly and any process fluids inside a flexible containment bag, providing extra protection for your operators, the process and the environment.

Easy to clean

Any bag filter housing needs to be quick and easy to clean. The faster you can drain and clean any residue, the faster you can get production running again.

Surface finish and roughness average (RA) values impact how much the process liquid clings to the surface when it’s being cleaned. Something as simple as a sloping base can help pool liquid into a drain position. Typically, the conventional dished bottom end used on a bag filter housing allows quick and easy drainage.

Optimal construction

If your bag filter housings aren't made of the right materials, the media they process may damage the housings through corrosion. Not only does this mean that you’ll have to replace your housing, but the quality of the final product may also be compromised.

To avoid this, you must choose the material based on the media being processed, and the pressure and temperature it’s processed at.

Where cleaning the housing is impractical, design features such as removable diaphragm plates can simplify the process and guarantee the total removal of any residual product.

Bag filter housing from Amazon Filters

Sometimes it’s not about the filters. The quality and construction of bag filter housing can have as much of an impact on your production as the filters themselves. That’s why we specialise in creating bespoke filter housing solutions that are designed to suit your production needs.

Exploring 6 key challenges of process filtration

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