How to Select the Proper Filter Cloth for Your Application

Filter Press Cloths – Overview

Filter cloths come in many shapes, sizes and fabric types. Filtration results can vary depending on the type of cloth being used.

Shown below is a typical Non-Gasketed (NG) design cloth on top along with a Gasketed (CGR) design cloth on the bottom.

M.W. Watermark Non-Gasketed and CGR Filter Cloths; Filter Cloth Selection Process

M.W. Watermark manufactures these designs along with others like the drape over, half cloth, backing cloth and most other types.

Matching the most appropriate filter cloths for a given project requires knowledge of the design needed as well as the process application.

Filter Cloth Selection

Determining the proper cloth construction requires knowledge of the slurry characteristics and the filtration requirements. Below are some of the factors we consider in the filter cloth selection process.

Contact M.W. Watermark to learn more about how to identify or measure these variables.

  • Is the cake or the filtrate a product?
  • pH?
  • Slurry temperature?
  • Slurry particle size?
  • Is the slurry preconditioned (Polymer, DE, Ferric, Lime, etc.)?
  • Abrasive, coarse particles?
  • Existence of solvents, oils or greases?
  • Number of filtration cycles per day?

The above data helps in determining the following:

  • Fabric raw materials / compatibilities
  • Type of yarn (fibers)
  • Fabric weave
  • The type of fabric finishing needed to produce the best filter cloth for the application

Materials / Compatibles Chart

M.W. Watermark Filter Cloth Materials and Compatibles; Filter Cloth Selection Process

Filter Cloth Fiber Types

Filter cloths are manufactured using synthetic fibers.

  • Monofilament: Single, smooth, continuous extrusion. Highest flow rates, good resistance to blinding, good abrasion and scaling resistance. Fibers are typically between 4 mil and 10 mil (.004″ to .01″) in diameter. Best cake release.
    M.W. Watermark - Monofilament Filter Cloth Fiber; Filter Cloth Selection Process
  • Multifilament: Multiple continuous fibers twisted together to form one yarn. Excellent retention for smaller particles. Good cake release.
    M.W. Watermark - Multifilament Filter Cloth Fiber; Filter Cloth Selection Process
  • Staple (Spun): Short lengths of fibers (similar in appearance to cotton) spun into a yarn. Tends to have a “hairy” appearance. Best solids retention. Poorest cake release.
    M.W. Watermark - Staple Spun Filter Cloth Fiber; Filter Cloth Selection Process

Filter Cloth Fabric Weaves

  • Satin: Smooth surface for excellent cake release and resistance to scaling and blinding.
    M.W. Watermark - Satin Filter Cloth Weave; Filter Cloth Selection Process
  • Twill: Shown with multifilament yarns. Somewhat smooth surface with good cake release. Excellent filtration of fine particles. Flexible fabric.
    M.W. Watermark - Twill Filter Cloth Weave; Filter Cloth Selection Process
  • Plain: Very tight weave. Excellent filtration of fine particles. Good cake release.
    M.W. Watermark - Plain Filter Cloth Weave; Filter Cloth Selection Process

Fabric Finishing

Finishing of the fabric enhances the cake release, filtration quality and stability.

  • Singeing: Removal of fibers on the surface of staple and felt fabrics to enhance cake release.
  • Calendaring: With use of heated compression rolls, the fabric is “melted” to adjust the permeability and provide a smoother surface for cake release.
  • Heat Setting: Through a wet or dry process to create a dimensional stable fabric that will not shrink, stretch, etc.

Visit our Filter Cloths 101 & FAQ webpage for more information.

Contact M.W. Watermark to discuss your particular application.

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About M.W. Watermark

M.W. WATERMARK wants to make a difference. We are passionate about the world’s water. We are innovative, focused on customer service and always try to exceed expectations. We are an environmentally conscious company with people who are energized, encouraged and inspired to make a difference on our planet by helping to keep our shared, finite water supply clean and usable for generations to come. We build amazing, custom water and wastewater treatment equipment. Together, we can make a difference.

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How to Select the Proper Filter Cloth for Your Application