Vessel Bags

Liquid Filter Bags for Bag Filter Vessels

Custom liquid filter bags for all standard and most custom vessels, in felt from 1 to 200 micron and mesh from 5 to 1,200 micron, with the ring or drawstring top your vessel needs.

Felt 1–200 Micron

Polyester, polypropylene, Nomex.

Mesh 5–1,200 Micron

Nylon and polyester mesh.

Standard & Custom

Bags for most vessels.

Ring or Drawstring

Plastic, steel or stainless.

Liquid Filter Bags

Find the Right Filter Bag

Choose your filter media, micron rating, bag size and top style.

Felt Bags

Depth filtration, 1–200 micron.

Mesh Bags

Monofilament and multifilament.

Bag Sizes

Standard #1 to #4 and custom.

Top Styles

Rings, handles, drawstrings.

How It Works

How a Bag Filter Vessel Works

Typical liquid filter vessels are top loading, with a hinged or threaded lid. A metal restrainer basket sits inside the vessel and supports the filter bag under pressure. Liquid enters the open top of the bag, passes out through the filter media and leaves the vessel, while the solids collect inside the bag.

Because the dirt stays in the bag, a change out is quick: open the lid, lift out the loaded bag and drop in a new one. The ring or drawstring at the top of the bag seals against the vessel so liquid cannot bypass the filter media.

Industrial liquid bag filters handle high flow rates and heavy solids loading at a low cost, which makes them a common choice for process liquids, oil, water, coatings, chemicals, food and beverage, and as a pre-filter ahead of filter cartridges and reverse osmosis systems.

Warning Signs

Signs It Is Time to Change Your Filter Bags

  • Pressure difference across the vessel keeps rising

  • Flow rate through the system drops

  • Particles show up in the filtered liquid

  • Torn seams, holes or a broken ring

  • The bag collapses or rides up in the basket

Need a new vessel? See our filter bag housings →

Filter Media

Felt vs. Mesh Filter Bags

Every liquid filter bag design starts with the media, and bag filters come in a variety of materials. Felt traps particles through its full depth, while woven mesh stops particles at the surface. Compare the micron ranges and materials, then pick the bag construction that gives the efficiency and performance your liquid needs.

Filter Media Filter Type Micron Range Materials Best For
Felt Depth 1 to 200 Polyester, polypropylene, Nomex High dirt loading at low cost
Monofilament Mesh Surface 5 to 1,200 Nylon, polyester Precise retention, reusable
Multifilament Mesh Surface 75 to 1,200 Polyester Economical coarse filtration
Felt Bags

Felt Liquid Filter Bags

AFF felt bags are made from high quality needle felt liquid filtration media. Felt is a low cost depth filter material with high dirt holding capacity and long service life, and it is available in a wide range of materials. We carry polyester, polypropylene and Nomex felts in the 1 to 200 micron range.

Felt bags are offered in singed or glazed finishes to reduce fiber migration and downstream contamination. Choose a polyester felt liquid filter bag for general service, polypropylene felt for broad chemical compatibility in water and process liquids, or Nomex for higher temperature liquids.

White needle felt liquid filter bags with plastic rings and handles

1 to 200 micron

Polyester and polypropylene

Nomex felt

Singed or glazed

Nylon monofilament mesh liquid filter bags with stainless steel ring tops
Mesh Bags

Monofilament and Multifilament Mesh Bags

AFF monofilament bags are made from precision woven monofilament fibers for accurate particle size retention. Nylon monofilament mesh is a common choice for paints, coatings and process water. Monofilaments are very strong and can be reused in most applications. Monofilament bags are offered in nylon and polyester from 5 to 1,200 micron.

Multifilament bags are woven from threads made of many filaments. They are a more economical option than monofilament bags. Particle retention is less precise, but they are very effective, and they are available in polyester from 75 to 1,200 micron.

5 to 1,200 micron

Nylon and polyester

Reusable monofilament

Economical multifilament

Top Styles

Rings, Handles and Drawstrings

The top of the bag is what seals it in the vessel. We offer plastic rings (often called flanges), plastic rings with integral handles, galvanized steel rings, stainless steel rings and drawstring tops, so every bag fits your vessel and your application.

Rings with handles make change outs faster and keep hands away from the dirty liquid. Steel and stainless steel rings hold their shape in demanding service, and drawstring tops fit open tanks and gravity systems.

Technician lifting a used liquid filter bag out of a stainless steel bag filter housing

Plastic rings

Integral handles

Galvanized or stainless

Drawstring tops

Bag Sizes

Standard Liquid Filter Bag Sizes

These are the common industry sizes for standard bag filter vessels. Exact dimensions vary slightly by vessel maker, so send us your vessel make and model, or measure your current bag, and we will match it. We also build bags for most custom vessels.

Bag Size Diameter Length
#1 7.06″ 16.5″
#2 7.06″ 32″
#3 4.12″ 8″
#4 4.12″ 14″
Custom Built to your vessel Built to your vessel
Industries

Liquid Filter Bags by Industry

Bag filtration cleans process liquids, coatings, chemicals, water and wastewater across nearly every industry.

Food & Beverage

Pharmaceutical

Manufacturing

Paint & Coatings

Municipal

Wastewater Treatment

Oil Field

Metal Working

FAQs

Liquid Filter Bag Questions

Send us your vessel model, liquid and micron rating, and we will match the right filter bag.

A liquid filter bag is a sewn bag of felt or woven mesh that sits inside a bag filter vessel. Liquid flows into the open top of the bag and out through the filter media, and the solids stay inside the bag. A metal restrainer basket supports the bag under pressure, and a ring or drawstring at the top seals it in the vessel.

Choose the micron rating from the smallest particle you need to remove and how clean the filtered liquid needs to be. Felt bags cover micron ratings from 1 to 200 and mesh bags cover 5 to 1,200 micron, so a 1 micron, 10 micron, 25 micron or 50 micron rating is a common starting point for fine filtration. If you are not sure, send us a sample or describe your liquid and flow rate and we will recommend a rating.

Felt bags are depth filters. Particles are trapped through the full thickness of the felt, so they hold a lot of dirt for a low cost. Mesh bags are surface filters woven from monofilament or multifilament fibers, so they give more exact particle retention, are very strong and can be reused in most applications.

We make filter bags for all standard bag filter vessels, including the common #1, #2, #3 and #4 sizes, and for most custom vessels. Send us the vessel make and model or your bag dimensions and we will build bags to fit.

Singeing and glazing are surface treatments for felt filter bags. They lock down loose fibers on the felt so fewer fibers migrate into the filtered liquid, which helps prevent downstream contamination and makes it easier to release the filter cake.

Monofilament mesh bags can be cleaned and reused in most applications. Felt bags are depth filters that hold dirt inside the media, so they are normally replaced once they are loaded.

We offer plastic rings, plastic rings with integral handles, galvanized steel rings, stainless steel rings and drawstring tops, so the bag seals correctly in your vessel.

Change the bag when the pressure difference between the inlet and outlet reaches the limit set for your vessel, when flow drops, or when you see particles downstream. Also replace any bag with a torn seam, a broken ring or damaged media.

Tell us the bag size or vessel make and model, the filter media and micron rating, the ring or top style, the liquid being filtered, its temperature and flow rate, and the quantity you need. A sample of your current replacement bag also helps.

Yes. We supply filter bag housings in carbon steel, stainless steel and aluminum in many sizes and configurations. Contact us with your flow rate and connection requirements.

Liquid Filtration

More Liquid Filtration Products

Housings, cartridges and filter media to complete your liquid filtration system.

Housings

Bag filter vessels and housings.

Cartridges

Pleated, melt blown and string wound.

Filter Media

Liquid filter felts and mesh.

Reverse Osmosis

RO membrane elements.

Need Liquid Filter Bags?

Send us your vessel make and model, bag size, media and micron rating, and we will quote the right liquid filter bags.