Pressing Onward: A Dewatering Blog

Secret Weapon Lowers Dewatering Costs In Metal Finishing

By Michael Stock


If you’re in charge of the dewatering end of a metal finishing line, you know the orders: keep throughput up and keep costs down. And the main weapon you have in this battle is the line’s filter press.

But what if your filter press isn’t following orders? What if it’s taking longer and longer to cycle, or it’s producing wet cakes or filtrate that could be setting your company up for discharge fines?

Clogged cloths defeat throughput

Either of these symptoms is a sign that your filter cloths could be clogging up with metal waste. In metal finishing, it happens to all presses over time. And when it happens, efficiency drops, and it takes longer to produce tight, dry cakes.

You can inspect the cloths and tell visually if they’re clogged. If cakes are dry around the edges and wet in the middle, that’s an even more definite sign of clogging. Also a sign that it might be time to buy new cloths.

To get throughput back, you’re going to have to spend some money.

Metal_Finishing_clogged_cloth_350px.jpgThis is an image of a cloth that hasn't been cleaned in years.
Yes, there's a gasketed filter cloth pressed into the filter plate!

Or are you?


The secret weapon

There’s a secret weapon in this battle; one that’s often overlooked: acid washing. Not the kind they use to produce fancy blue jeans, but the kind that dissolves metal residue in filter cloths. By taking the press off line for a half hour or less and pumping an acid solution through it, you can often restore much of the performance of your filter cloths and postpone buying new ones. After all, when acid meets metal, acid usually wins. Depending on your process, you may have to use this secret weapon as much as twice a week or as little as once every couple of months.


How important is this trick? It depends on how important throughput is to your operation. If you’re running below full capacity, you can probably wash your cloths less frequently. But if you’re already at full capacity, and you’re planning to expand production, a stepped-up acid washing maintenance program could boost the efficiency of your existing press and avoid not just the cost of new cloths, but maybe also the cost of buying another whole press. That’s a big win.

Would it make you a hero? In the never-ending battle for high throughput and low cost, you be the judge.

Call 844-704-2920 to ask about acid washing, wastewater in metal finishing or anything related to filter presses!

To talk about these and other issues related to metal or surface finishing, see us at the upcoming SUR/FIN show in Atlanta, June 19 - 21, Booth 120. See what we'll be talking about at the show, here.

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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