Part II: Filter Cloth Troubleshooting and FAQ

In Part I of our filter cloth series, Filter Cloth 101 , we covered terminology and material types. In this post we hope to answer frequently asked questions about filter cloths, filter cloth installation, and trouble-shooting.

If we don’t answer all of your questions, please feel free to ask one in the comments section – we’ll get back to you. Or, you can always call our Sales/Services Staff: 616.399.8850.

Filter Cloth FAQ

Q: What is the micron rating of this cloth?

A: Filter cloth does not have a micron rating. Cloth air permeability, or porosity, is measured using the Frazier Air Permeability scale. The unit of measure is cubic foot per minute, or CFM, which is a cloth permeability measurement. The ranges of CFM are wide, and are determined by the thread counts and weight of a fabric.

Q: How can I make the installation of gasketed filter cloths faster?

M.W. Watermark Air Hammer - Filter Cloth Installation Tool
Air Hammer

A: Depending on your press operation, changing cloths can be labor intensive and difficult, and often the down-time is problematic. Here are a few different solutions:

  1. For easier installation: Purchase an air hammer (P/N 4000-0235) which greatly speeds the filter cloth installation.
  2. For less down-time: Purchase additional filter plates to “swap out” between cycles, so you can replace cloths in the extra plates while the press still runs at full capacity.
  3. Let us take care of installation. Send your filter plates with old cloths to M.W. Watermark, and have our staff clean the plates, change the cloths & gaskets, and ship them back. Usually this service can be done within 2-3 days.

If you’re not sure how to install a gasketed filter cloth, take a look at our how-to video/blog post: How to Install a Gasketed Filter Cloth. Here, you can find instructions on How to Install a Non-Gasketed Filter Cloth. Or, give our Sales/Service Team a call (616.399.8850).

Q: My filter cloths are wearing out at the center feed neck/corner feed. What can I do?
A: You can ask for either a latex reinforced cloth, or in an extreme case, a rubber barrel neck to protect against wear in those areas.

Q: How can you test a new filter cloth for our application?
A: First, contact our sales or process experts for a recommendation. Once a cloth type is selected, run a test on a shortened stack in your filter press. This can be done by moving the “end plate” to cut off the stack so that just the test cloths are used.

To protect the plate at the end of the stack, use a back-up plate to support the tail plate. Monitor the pressure, as it will fill fast, and run the press with the shortened stack. You should see results quickly.

Q: Can I clean the cloths with a pressure sprayer?
A: You can, but take care to not get too close with the spray tip. Only use the sprayer in a “fan” spray pattern and keep spray pressure under 1000 PSI.

Q: Can we clean cloths with chemical cleaners?
A: Polypropylene filter cloths can handle both caustic and acidic solutions. Nylon, polyester, and felt cloths need special consideration and may be damaged from these chemicals. Contact M.W. Watermark™ about your specific situation.

Q: How can I extend my cloth life?
A: Filter cloth life is shortened by chemicals, mechanical wear, abrasion, and blinding. We can help to determine whether your cloths are being attacked by your process chemicals. Mechanical wear can be reduced by using a more durable cloth. Blinding often comes from “slamming” sludge into the press.

Consider an Auto Feed Pump Control System, or an AFPCS to automatically and gradually increase pressures. “Pre-coating” a press with DE or similar products can also add substantial life to cloths. The coating protects against wear and minimizes blinding.

Q: How do I install a filter cloth?

A: We have published step-by-step instructions as well as created how-to videos to help you with this task. Please click on the appropriate link for your type of cloth for our installation posts.

Gasketed Filter Cloths (CGR)

M.W. Watermark CGR Filter Cloth

Non-Gasketed Filter Cloths (NG)

M.W. Watermark NG Filter Cloth

Head Filter Cloth (CGR)

M.W. Watermark Head Filter Cloth Installation

If you have any more questions please leave a comment or contact us.

Part II: Filter Cloth Troubleshooting and FAQ

5 thoughts on “Part II: Filter Cloth Troubleshooting and FAQ

  • December 2, 2014 at 2:55 pm

    We recently replaced our filter plates with newly re-clothed plates, however, the new plates are not filtering as well as the old ones and we are getting blow through in our treated water. Also, the filter cake is not as dry as it previously was, why is this happening?

    Thank-you for your input, it is appreciated,
    Joyce Fern
    Waste Treatment Operator

    • December 3, 2014 at 10:15 am

      Hi Joyce,

      Thanks for your message.

      Wet cake can be the result of a fabric material change; the original fabric may have been a more open weave allowing for better flow, in some cases a heavier fabric with a tighter weave can immediately plug up with solids and blind off creating wet filter cake. Did you re-order the same cloths or is it possible your new cloths were made of a different fabric?

      Noticeable blow through is typically a loose cloth retainer on the slurry inlet, or a cloth not seated properly in the groove. If there are high spots in the rope (gasketing) around the cloth this can allow solids behind the cloth and they pass through with the filtrate.

      Check out your head cloth and make sure the nut is on properly and check the gasketing on each plate to make sure it is in the groove with no bumps. If you have any other questions, or, if the filter cloth you have isn’t working for you please feel free to give us a call at 616-399-8850 or email us:



      • December 3, 2014 at 11:17 am

        Thank-you Jim for your input. I cannot say for sure that the new clothes are the same material as our old ones, but I can certainly find that out. I will also check to make sure the clothes are seated properly and that the head plate is assembled correctly.
        If we continue to have issues I will certainly request a service visit,


  • February 27, 2016 at 3:33 am

    How i can determine the shelf life of filter cloth? What experimental that suitable for determine the shelf life of filter cloth.

    • February 29, 2016 at 9:36 am

      Hi Maya, thanks for your question about filter cloths. Please contact our Sales & Service Team at (616) 399-8850 and one of our staff will be happy to help you. Thanks again!


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