Pressing Onward: A Dewatering Blog

Filter Cloth Management For Tough Slurries - Easy As Pie

By Michael Stock


goopy-viscousPre-coating can help extend cloth life.

If you’ve been keeping up with our blog posts, you’re probably already familiar with how important it is to match the filter cloths in your press to your specific type of slurry and process. For a refresher, see this post on the wide range of material, weave, fiber types and thread counts we offer to meet any combination of slurry characteristics.

But there are some applications for which no type of cloth can do it alone. Some processes in food & beverage operations, automotive plants, steel mills and other heavy industries can produce oily or sticky sludges that will quickly blind a filter cloth, make it impossible to clean, and shorten its lifespan from months to weeks or less.


Like flour on a rolling pin

In these cases, you can extend cloth life and save money by investing in a system that pre-coats cloths with a material (usually diatomaceous earth) that prevents oily, sticky sludge from binding to the cloth fibers. If you’ve ever made a pie crust from scratch, think of coating the rolling pin with flour to keep the dough from sticking to it and you’ll get the idea.

In addition to extending cloth life, pre-coating can make your dewatering process run more smoothly. Cakes release much more easily, and there’s less downtime caused by cleaning and changing cloths. Costs include a pre-coat skid with its own pump, tank and piping; plus the pre-coat material itself and the time involved in setting up a PLC program to control it all.


Is pre-coating for you?

For some of our customers, pre-coating is an obvious choice. Others prefer frequent cloth changes. The only way to know what’s right for your operation is to weigh the costs and benefits of the two scenarios along with other factors such as your capital strategy, plant environment and workflow. The best way to sort it all out is to have your process analyzed by the folks at our lab. They can help you identify the right cloths and the right pre-coat system to protect them. Then they’ll help you work through the options so that you can decide which is a better fit for your operation: pre-coating your cloths, or replacing them more frequently.

Either way, there’s no reason to let stubborn sludge ruin the party. Work with the experts at Evoqua to get the recipe right, and the rest is a piece of cake. Or, if you prefer, pie.


Call us with your favorite pie recipe or to order parts for your filter press, including filter cloths!  New, repair, rebuild or retrofit.  Call  (844) 450-2910.

Looking for more ways to improve the performance of your filter press? Download our guide for more dewatering tips, tricks and maintenance advice!

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