Evoqua United States - Canada - EN

FAQs for Filter Presses

Filter presses from Evoqua separate suspended solids from liquids

How long will it take to fill my filter press with slurry, and how long should the cycle time be?

This can vary greatly depending on your process and application. It can be anywhere from 10 minutes to 10 hours or more. We can do a test to determine the answer for your specific application. For a quote on testing, we require a completed data form.

​​​What is the best type of filter plate cloth for my filter press and t​​he process I'm running?​

This depends on your process. Cloth selection is as much an art as it is a science. Based on our 1,000 years of combined experience and lab testing, we can make an expert recommendation to you. We supply cloths based on criteria you give us and based on sample processing we do in our lab. Should your process change, we recommend that your cloth type be evaluated for suitability.

The following is general information to help you understand cloths and how they work. For detailed questions, call our customer service department at 800.245.3006.

Cloths for non-gasketed plates are hung over the plate, extending from top to bottom, and are held in place by eyelets that fit over the cloth-pins on top of the plates. With the non-gasketed plate, the filter cloth provides the seal between the plates. Leakage will occur during operation even though Evoqua supplies the non-gasketed plate cloths with latex edging. The latex will cut down the wicking action somewhat, but will not eliminate it.

The gasketed plate allows less leakage than the non-gasketed plate due to an O-ring seal around the chamber and filtration ports. The gasketed cloth has a high-density sash cord sewn around the cloth's perimeter that is caulked into a groove on the plate.

The type of cloth used is determined by the type of process or application performed by the filter press, the operating environment, and the performance required by the filtering media (filter cloths).

The filter cloths come in many different materials including polypropylene, polyester, cotton, and other synthetic materials. The cloths are made from monofilament fibers, multifilament fibers, or spun fibers. The smooth surface characteristic of monofilament fibers can help to improve cake release properties. The uniform circumference of monofilaments also enables fabrics to be produced with consistent pore sizes. Multifilament and spun fibers are produced by twisting several smaller diameter monofilament fibers together into a single strand. They are used to produce fabrics that require a very tight weave and fabrics where high flow rates are not critical.

Filter cloths also come in many different styles of fabric weave. ​

Mesh opening or pore size is also an important consideration when selecting the proper filter cloths for a particular application. The mesh opening or pore size is determined by the number of fibers, size of the fiber, and the type of weave. These factors in turn govern flow rates, particle retention, and the strength of the fabric itself. As shown below, these two fabrics, having the same type of open area, will have similar flow rates, but the fabric on the left will retain finer particles.

How can I tell what kind of filter plate cloth I have on my filter press?

This is difficult to determine from just looking at your filter cloth. The question assumes you bought your filter press from us, in which case we will have your information on record.

Call us with your serial number at 800-245-3006.

If you did not buy your filter press from us and you have questions about your cloth you should still call the number above, and we can walk you through some steps to help figure out your problem. We can also send slurry samples to our in-house lab to help assess your situation. Call us for a conversation.​

What micron size are my filter cloths?

There is no micron rating on filter cloths. They are rated by air permeability.

What size feed pump do I need for my filter press?

It depends on your process, but general guidelines are as follows:

Up to 5 cu. ft. 1" air operated diaphragm pump

5 to 15 cu. ft. 1½" air operated diaphragm pump

15 to 25 cu. ft. 2" air operated diaphragm pump

25 to 50 cu. ft. 3" air operated diaphragm pump

50 cu. ft. and above multiple pumps

 

We furnish a full line of feed pumps. Please call our customer service department at 800-245-3006 for your best sizing and price.​​

How do I size the compressor for my filter press feed pump and air blow?

It depends on your process, but general guidelines are as follows:

 

A 1" pump should have a 5 hp compressor.

A 1½" pump should have a 10 hp compressor.

A 2" pump should have a 12-15 hp compressor.

A 3" pump should have a 20 hp compressor.

I changed the polymer (or other chemical treatment type) and now get sloppy filter cakes out of my filter press. What can I do?

Changes in chemical and physical treatment may alter the performance of your filter press. We can assist you in optimizing your press performance by performing lab testing. Please contact our customer service department at 800-245-3006.

My press is dropping sloppy cakes, and I think that my cloths are blinding. What do I do?

This usually means it is time to clean your filter cloths.

Why won't my filter press build a good filter cake?

Possible causes are:

 

Dirty filter cloths. What to do: clean or replace filter cloths.

Malfunctioning (low) feed pump. What to do: clean and adjust as needed.

Incorrect treatment or treatment change. What to do: contact customer service at 800-245-3006.

How many more plates can I add to my filter press?

It depends on:

The amount of opening space left in your press

How much clean-out space you want to sacrifice

If your press has an expansion piece

 

You may be able to buy new, longer sidebars if you have a bolt-on style press.

Call customer service at 800-245-3006.

​How many plates can I take out of my filter press?

Safely, none.

We can provide you with a back-up plate if you need to reduce the capacity of your press.

Call customer service at 800-245-3006.

How can I tell what kind of filter plate cloth I have on my filter press?

This is difficult to determine from just looking at your filter cloth. The question assumes you bought your filter press from us, in which case we will have your information on record.

Call us with your serial number at 800-245-3006.

If you did not buy your filter press from us and you have questions about your cloth you should still call the number above, and we can walk you through some steps to help figure out your problem. We can also send slurry samples to our in-house lab to help assess your situation. Call us for a conversation.​