Standard Felt Filter Bags

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Standard Felt Filter Bags


  • We offer a full line of felt materials and micron ratings
  • Conventional sewn bags or the PolyWeld® welded seam bags available
  • FSI PolyLoc® ring or other common bag rings available on most bags
  • Heavy Duty and Extended Life designs available to suit your filtration needs


About Standard Felt Filter Bags

When it comes to felt filter bags, FSI has the answer. Our years of experience give us an advantage over our competitors, and our felt filter bags show it. Our felt bags are designed to withstand higher solid loading, and are suitable for applications using vessel or open filtration systems.

FSI’s “Comprehensive Manufacturing Control” philosophy insures that we will maintain our status as the industry leader in all phases of the filter business. Our integrated technology, control over our manufacturing and quality leads to consistent performance. With FSI filter bags, you can count on a quality product every time.

We start with the finest material possible. FSI makes its own fiber to produce the felt material used in our felt filter bags inhouse, guaranteeing the highest quality. Our Extended Life filter bag provides superior filtration of all sized particles, as well as up to twice the dirt holding capacity of a standard filter bag.

Our no-bypass welded seams eliminate the possibility of fluid bypass through needle holes. We provide a variety of glazed and singed finishes to inhibit fiber migration. FSI also offers polyester inserted felts. These inserted felts include a reinforcing scrim needled inside the felt material, to provide added strength and durability, when a restrainer basket is not being used.


Video: How to Install a Bag Properly


Filter Media

  • Felt, high temperature
  • Felt, nylon
  • Felt, polyester
  • Felt, polypropylene
  • Felt, Teflon®

Maximum Operating Temperature

Polypropylene: 200-220° F (93-104° C)
Polyester: 275-325° F (135-162° C)
Nylon: 275-300° F (135-149° C)
High Temperature: 400-450° F (204-232° C)
Teflon: 450-500° F (232-260° C)

Micron Rating

Polypropylene: 1, 3, 5, 10, 25, 50, 100
Polyester: 1, 3, 5, 10, 25, 50, 75, 100, 200
Nylon: 5, 10, 25, 50, 100
High Temperature: 5, 10, 25, 50, 100, 200
Teflon: 1, 5, 10, 25


Polyester multifilament
Nylon monofilament


1: 7” x 16” (17.78 cm x 40.65 cm)
2: 7” x 32” (17.78 cm x 81.28 cm)
3: 4” x 8.25” (10.16 cm x 20.96 cm)
4: 4” x 14” (10.16 cm x 35.56 cm)
5*: 6 7/8” x 34” (17.46 cm x 86.36 cm)
6*: 6 7/8” x 16” 1/2” (17.46 cm x 41.91 cm)
7: 5 1/2” x 16” (13.97 cm x 40.64 cm)
8: 5 1/2” x 22” (13.97 cm x 55.88 cm)
9: 5 1/2” x 33” (13.97 cm x 83.82 cm)


Polypropylene PolyLoc®
Polyester PolyLoc®
Nylon PolyLoc®
Snap ring metal
Stainless steel snap ring
Commercial steel ring
Commercial plastic ring
Ronningen-Petter snap ring
Ronningen-Petter plastic ring
Ronningen-Petter flange



Chemical Compatibility


  • Recommended for most conditions up to the maximum temperature of the material. Recommended for most conditions up to the maximum temperature of the material.
  • Fair. May be acceptable, but testing is recommended. Fair. May be acceptable, but testing is recommended.
  • No data available. Customer testing required. No data available. Customer testing required.
  • Not recommended. Not recommended.


Download literature pertaining to this product

Download full product catalog


Other FSI Filter Bag Literature:

Filter Fabric Qualities & Bag Data Chart

Filter Bag Flow Rates & Micron Availability Chart

How to Order

Download ordering instructions in PDF format

Locate your representative or call 1.800.348.3205.

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