Maintenance Tip of the Month: Measuring Filter Bags & Cages for the Perfect Fit

In this Maintenance Tip of the Month, Keith Ogilvie shares expert tips on measuring filter bags and cages for the perfect fit in your baghouse.

Properly fitting bags and cages are integral to achieving long filter bag life and optimum baghouse performance.

Of course, the best way to ensure a properly fitting filter bag for your specific baghouse is to have a Micronics technical representative visit your location.

Or – if extra bags are available – you may send a sample to one of Micronics’ state-of-the-art facilities for measurements such as Olive Branch, MS, or Augusta, Georgia. We have worldwide facilities in Canada, Brazil, Mexico, Australia, China, and India to meet your filter bag replacement needs as well.

Micronics provides Total Engineered Filtration Solutions for your baghouse including Filter Media, Baghouse Maintenance & Repair Services, Baghouse Parts & Accessories, Dust Collection Training, and Baghouse Retrofits.

Whatever your dust collection needs, we are your solutions partner. Like you, we love clean air!

Learn more about Keith’s tips for measuring filter bags and cages below.

Measuring Filter Bags

Measuring Flat width of Top Load, Snap-Band Filter Bag

Top Load, Snap Band Filter Bag – Felt

  1. Flat width: Flatten bag and measure the width across.
  2. Length: Measure along the seam running the length of the bag. Start at the center of the snap band and end at the first stitch at the bottom of the bag.
  3. Cage-to-Bag (Bag-to-Cage) fit:  Should have ¼” to 3/8” pinch; the bottom of the bag should have about a thumb width between the bottom of the cage and the disc bottom of the bag.

Top Load, Snap Band Filter Bag – Woven Fiberglass

  1. Flat width: Flatten bag and measure the width across.
  2. Length: Measure along the seam running the length of the bag. Start at the center of the snap band and end at the first stitch at the bottom of the bag.
  3. Cage-to-Bag (Bag-to-Cage) fit:  Should have 1/8” or less pinch, but shouldn’t be stretched tight around the cage.

Top Load, Snap Band Filter Bag – Felt with membrane

  1. Flat width: Flatten bag and measure the width across.
  2. Length: Measure along the seam running the length of the bag. Start at the center of the snap band and end at the first stitch at the bottom of the bag.
  3. Cage-to-Bag (Bag-to-Cage) fit:  Should have 1/8” or less pinch, but shouldn’t be stretched tight around cage.

Shaker style Filter Bag

  1. Flat width: Flatten bag and measure the width across.
  2. Length: Measure along the seam running the length of the bag. Start at the end of the snap band to the end of the bag, not including the tail.
  3. Length of the tail: Measure along the seam from the end of the bag to the end of the tail
  4. Flat width of the tail: Flatten tail and measure width.
  5. Determine if the tail is 3-ply or 4-ply by pinching the material and feeling for layers.
  6. If there is a wear cuff at the snap band end of the bag, measure the length and width.

Measuring Cages

Measuring cage to ensure proper fit in your baghouse
Measuring the diameter of cage to ensure the perfect fit

Measuring Cages, Step-by-Step

  1. Full length of the cage:  Measure from top to bottom.
  2. Diameter: Measure diameter in the middle of the cage at the widest point between wires. Ideally, using a Pi Tape to determine circumference will yield a preferred measurement.
  3. Bottom construction: Determine if the bottom cup is crimped or if the wires are welded to the cup.
  4. Number of rings: count the number of rings.
  5. Space between rings:  Measure the space between the rings. Note: the space between the last ring and the bottom of the cup may be different
  6. Number of vertical wires: Count the number of vertical wires running the length of the cage.
  7. Material: Plain steel, galvanized, coated, 304 stainless steel, or some other material?
  8. Determine the top construction of the cage.
    • If the top has a split top, measure the space between the groove in the split top and the end of the top
    • If the top has a venturi, measure the length of the venturi.

The Micronics Engineered Filtration Group is here to help

Proper fit for your baghouse’s dust collector bags and cages is an integral part of ensuring excellent baghouse performance. The Micronics team and trusted brands – AFT, SOLAFT, NFM, Filterfab, SFM, CPE, and UPC – love clean air and assisting you in optimizing your baghouse’s performance.

If you would like assistance with measuring filter bags and cages or installing filter bags in your baghouse, you can benefit from Micronics’ dust collector training seminars!

If you don’t want to deal with the manpower requirements & hassle associated with filter bag installation, Micronics has some of the best full-time, certified baghouse maintenance & service crews in the industry.

Contact Us and let us know how we can help with all your baghouse filter bag, parts, and service needs.

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Looking to optimize your baghouse performance?

Micronics provides Total Engineered Filtration Solutions for your Baghouse including Filter Media, Baghouse Maintenance & Repair Services, Baghouse Parts, Dust Collection Training, and Baghouse Retrofits.

Whatever your dust collection needs, we are your global filtration solutions partner. Like you, we love clean air!

Contact Us