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?
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:
- For easier installation: Purchase an air hammer (P/N 4000-0235) which greatly speeds the filter cloth installation.
- 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.
- 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.