Do you have questions or concerns regarding your filter press? Here are some common filter press questions and their solutions.

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How can I tell when my filter cloths are dirty?

Usually you will need a longer cycle time to achieve the same cake dryness. You may also notice sloppy cake or discharge flow is less.

How do I clean my filter cloths?

Use a spatula to scrape cake off the surface. Cake buildup can cause bending of the press frame. Excessive bending can lead to equipment failure! Keep the cloths and plates as clean as possible, especially along the sealing surface.

Keep the following in mind when scraping cloths:

• Use care not to cut or rip the cloth.
• Cloths deteriorate over time and become more fragile and susceptible to tearing.
• Make sure the edge of the spatula is smooth.
• Do not tap the spatula on hard objects to remove cake from the spatula surface. This may form dents or tears in the spatula surface that can tear cloths.
• Lodged particles must be removed periodically to maintain high filtration rates and dry cakes. A high-pressure, cold water, spray unit with a capacity of 800- psi (55-80 bar) and 2-10 gpm (8-38 lpm) should have sufficient capacity. A broad spray nozzle should be used at a safe distance. If the pattern is too intense at a close distance, the cloth weave may be forced apart, leaving openings that allow sludge.

If high-pressure washing does not improve performance, carefully pull back a corner of the filter cloth and check the drainage area and discharge parts of the plate for solids buildup. If there is any buildup, the cloths must be removed, and the plates and cloth backs cleaned. Excessive buildup causes slow filtration cycles and can lead to plate breakage.

If more thorough cleaning is required, you can use a chemical process to dissolve the entrapped particulate.

A recirculation cleaning method using a particulate dissolving solution is the most effective cloth cleaning method. This method circulates an acid, caustic, or cleaning solution through the press to dissolve built up particulate. The type of solution depends on the slurry.

Be extremely careful when handling acids or caustics! Eye protection and protective clothing is required. Should you get acid or caustic in your eyes or on your skin, rinse with water immediately and seek medical attention if necessary. Notify your supervisor of the incident.

Do not acid or caustic wash non-gasketed filter plates unless extra precautions are taken to contain the leakage between plates.

Consult the chemical compatibility chart in the safety section of your O&M manual to ensure safe and proper operation of the press.

Setup & Requirements

• Storage tank of sufficient capacity to fill the press and allow for recirculation—approximately1.5 times the holding capacity of the press.
• A low-pressure (20-30 psi [1.4-2.1 bar]) pump.
• Necessary plumbing (hoses or rigid PVC pipe) to isolate the press from the sludge stream and allow for both recirculation to the storage tank and final draining of the spent solution. A throttling valve installed in the return line to the tank may be necessary to ensure complete top to bottom press filling and washing of the cloths.

Procedure

1. Clean filter cloths of all external material with a nylon cleaning spatulas.
2. Close the press.
3. Disconnect the center feed line from the sludge pump.
4. Connect the outlet of the acid pump to the center feed line of the press.
5. Connect the filtrate discharge outlet of the press to the recirculation tank.
6. Open the feed line to the press.
7. Start the feed pump. It may take considerable time to fill all the chambers of the press before the solution returns to the storage tank. Continually inspect the press for leakage during filling and circulation.
8. Allow the solution to circulate for one to two hours.
9. Turn off the feed pump.
10. Perform an air blowdown to purge any remaining solution from the press.
11. Disconnect the wash system and reinstall the sludge pump and outlet lines.
12. Normal filtration cycles can now be performed.

The plates can also be "dip washed" by immersing them in a tank of solution. The immersion method is less efficient than through-washing in the press and will require a longer soak time. The plates will also float and require some method to keep them submerged.

How long do cloths last?

They could last as little as six months or as long as five years. It depends on many things:

1. Your process.
2. How often you run your filter press.
3. What you run through your filter press.
4. How well you maintain your filter cloths.

It‘s probably time to change your cloths when you see abrasion, stretchiness, folding, holes, poor cake, dirty filtrate or when conventional cleaning techniques don‘t restore the performance of your filter press.

How do I change my cloths?

First, remove the used filter cloth. To remove a filter cloth from a gasketed plate, insert a thin bladed screw driver into the groove at the outer edge of the caulking and pry out a small section of the cloth. Grab the sash cord caulking with a vise grip pliers and pull the remaining cloth out of the caulking groove. Do this on both sides of the plate. Pull the cloth through the center feed eye of the plate. After the cloth is removed, inspect and remove any accumulated solids from the groove before inserting the new cloth.

To remove a filter cloth from a non-gasketed plate, use diagonal cutters or snips to cut the ties (if supplied) on the vertical sides and lift each side of the cloth off of the cloth-pins on the top edge of the plate. Pull the cloth through the center feed eye of the plate.

Installing

On both gasketed and non-gasketed plates having a center feed eye with sewn centers, you will need to fold the cloth on one side into a small section so that it can be inserted through the center feed eye. Once you pull the cloth through the eye, unfold it for caulking on the gasketed plate, or hanging on the non-gasketed plate. On gasketed plates, place the cloth against the plate and tap in a small section of the sash cord or O-ring on the top to hold the cloth in position. Line up and caulk the diagonal sections first to ensure proper alignment of the cloth. Distribute the caulking one the sides, top and bottom by caulking in the center of these long sections first. Proceed to insert the balance of the caulking, ensuring that the caulking is distributed evenly. Even though there may appear to be a surplus of material, this can be worked in easily.

The tool for installing the retaining material (O-ring caulking and sash cords) is a simple wedge of polypropylene or some other non-shattering type material. The recommended size for the tool is 1“ (25mm) thick x 3“ (75mm) wide x 8“ (200mm) long with one end tapered down to 5/16“ (8mm) thick (available from USFilter, part #). CAUTION: Do not use a metal wedge since this may damage the cord or filter cloth.

On non-gasketed, lift the cloth over the cloth dogs on top of the plate. Then join the two edges on the sides of the filter plate with wire ties or similar clips

How do I change my end plate cloth?

Unlike intermediate filter cloths, the end-plate (head and tail) cloths do not have a sewn-in centerfeed eye. The endplate cloths would be installed as described in the previous question; however, the head-plate cloth must have the centerfeed hold cut before installation.

To do this, remove the old head cloth by first removing the centerfeed assembly‘s clip nut. Then, tap the corners of the new end-cloth into the head-plate making sure it is positioned correctly. Cut out the cloth around the centerfeed pipe using the equivalent of a hot knife, sottering gun or the like. This will seal the edges of the cut to prevent possible fraying of threads in the cloth. After the hole has been cut, finish installing the head cloth, then re-attach the clip nut.

When should I change my gaskets?

It‘s a good idea to change your gaskets whenever you change your filter cloths. Also, if you are getting excessive leakage out of the press while maintaining correct hydraulic closure pressure, this may be a sign that it is time to change your gaskets.

Gasket life will depend on many factors, such as length of filtration cycle, temperature, and excessive closing force. Gasket replacement should take place if the gasket appears to be delaminating or shredding into small particles. Also, if excessive temperatures exist and cycles are very long, the Nordel elastomer (standard gasket material) may go into additional cure, causing it to harden slightly. If the gasket life of the Nordel elastomer is unsatisfactory, contact USFilter for a suitable replacement.

How do I change my gaskets?

1. Insert the gasket starting at the bottom center of the filter plate using a wood or plastic mallet. Push the gasket into the groove around the outer edge of the plate until it mates at the center of the plate. Many installers will incorrectly stretch the gasket material. This reduces the cross section, making it easier to insert. However, by stretching the gasket material for easier installation, it has a tendency to creep and open the butted joint of the gasket, causing a leak.
2. Cut the gasket approximately 1/2“ (12mm) to 1“ (25mm) longer than required, cutting the end squarely.
3. Apply one or two drops of Eastman 910 (or equivalent „super glue“) to one end of the gasket and quickly join it to the other end. Hold it under hand pressure for approximately 30 seconds. Then crowd the excess gasket into the groove to ensure fullness of gasket material.

Install the discharge eye gaskets in the same manner.

NOTE: When gasketed plates are first put into use, the new gasket material may be slightly sticky or gummy and cause gaskets to pull out of the grooves when plates are separated. This condition is eliminated as product film is built up. If any gaskets show this characteristic, apply a silicone spray until the press has been used several times.

How do I change my center feed pipe assembly?

If the press is leaking (around the locknut on the 470mm size or from the bottom leg drain holes on 630mm and larger size presses) during the start-up of the feed process, the problem is usually leakage past the center feed quad ring seal. The quad ring may not seal for several reasons.

First Check For The Cause

Did the locknut on the outside of the press head loosen during shipment? If so, tighten the locknut using a spanner wrench, pliers, or pipe wrench.

Was extra field piping and/or manifolding added to the center feed pipe without proper support? Unsupported loads on the center feed pipe can cause the pipe to move off axis and unload the quad seal on one side. If this is the case, properly support all external piping. Loosen the piping from the factory-supplied piping and/or valve and realign the feed pipe so that it is perpendicular to the plate surface. Tighten the locknut and reinstall the supported piping.

Was the center feed pipe rotated during the field installation of extra piping/ manifolding? This could unseat the quad seal causing leakage around the seal. No feed pipe movement will reseat it.

Follow These Steps To Fix It

1. Open the press and shift all of the plates to the open position (toward the cylinder head). The inside surface of the head plate will have a centrally located clip nut approximately 0.5“ (13mm) thick that retains the filter cloth on the clip nut seat. This clip nut should be removed with a spanner wrench or pliers.
2. If the press has non-gasketed plates, lift the cloth off the top cloth pins. If the press has gasketed plates, the cloth must be removed from the caulking groove so that the top 2/3 can be peeled down to expose the center feed and allow the movement of the center feed pipe.
3. Loosen the locknut and back it off 2 to 3 inches (50 mm to 75 mm). Carefully push the center feed pipe out of its counterbore in the head plate. This allows access to the quad seal and its mounting land. Reinstall the seal onto the land. A few small drops of super glue may be applied to help retain the seal.
4. Reinstall the liner pipe into its counterbore and tighten the locknut making sure that the pipe remains perpendicular to the plate.
5. Reinstall the filter cloth

How often should I change the oil in my hydraulic system?

Under normal conditions, you should usually change your hydraulic oil once a year, or every 2,000 operating hours. Under severe conditions, the oil will need to be changed more frequently.

How often should I change the hydraulic filter?

Whenever you change your oil, you should change your filter.

Filter Press FAQ

Cleaning filter cloths, reducing cycle time and more!

Filter Press & Press Parts/Systems

What is a Filter Press?

A Filter Press is a piece of equipment used in liquid/solid separation. Specifically, the Filter Press separates the liquids and solids using pressure filtration, wherein a slurry is pumped into the Filter Press and is dewatered under pressure. The Micronics Engineered Filtration Group is a trusted expert in liquid/solid separation and offers a wide range of Filter Press types to suit your application needs for trouble-free, economical dewatering including: Sidebar Automatic, Manual Overhead, Automatic Dual Overhead Beam, Stainless Steel Clad, Explosion-proof Filter Presses, Vacuum Filter Presses, and Hand Filter Presses.

The four main components of a Filter Press include the frame, filter plates, manifold (piping and valves), and filter cloth, the key ingredient for optimizing Filter Press operations.

To learn more about “What Is a Filter Press?,” please view our informative video here. If you have any questions, please contact us and our expert team of Sales, Service and Applications Engineers will assist you with optimizing your existing Filter Press operation or help you with sizing new filtration equipment.

What is an air-over-oil filter press?

As you probably know, most filter presses use a hydraulic cylinder for closing, clamping, and opening of the plates in the plate stack. Hydraulic cylinders may be powered manually, air-assisted, or powered electrically. The hydraulic solution used depends upon the specific application as well as the size of the filter press required. An Air-Over-Oil Filter Press relies upon an air-assisted hydraulic cylinder. Air-assisted hydraulic cylinders use an air-operated intensifier pump to build hydraulic pressure for closing and clamping of the filter press. Air is directed to the opposite end of the cylinder for opening the filter press. This is in contrast to Electro-Hydraulic powered cylinders that use an electric motor and pump to close and open the filter press. Contact us to learn more about various hydraulic power pack solutions and how to troubleshoot problems.

What is the highest pressure I can pump to my filter press?

Filter presses are designed generally for two pressures, 7 and 15 bar (100 and 225 psi), although special machines are made for higher pressures. Check the equipment manual to ensure you do not exceed the pressure your filter framework was designed for. If you need assistance, measure your cylinder ram size, note the hydraulic pressure and contact us for help.

What is the best pump for a filter press?

Many pump types are used with good results, depending upon the characteristics of the material being processed. Air diaphragm pumps do not shear flocculated slurries and are the most common type of pump used. An added advantage to this type of pump is that the air drive stalls when filtration is complete. Positive displacement pumps are used on high pressure filters.

Want more information on Filter Press Feed Pump? Feel free to contact us.

Can I easily replace my existing hydraulic power pack?

Yes, we manufacture modular power packs for both air/oil and electro/hydraulic closure. These are easily installed in any brand of filter press and are capable of running simple and automatic machines. In some cases, it may be required for an additional control panel to be included.

Is a filter press or centrifuge best suited to my dewatering/filtering application?

A Filter Press, such as those manufactured by Micronics, is a mechanical liquid-solid separation machine that utilizes filter plates, filter cloths, and high pressure to separate solids and liquids. A centrifuge is a machine that spins rapidly and utilizes centrifugal force to separate liquids and solids and is considered a continuous dewatering machine. There are many considerations when determining whether a filter press or centrifuge would be optimal for your particular process. Filter presses are widely and successfully used in a host of industrial and municipal water and wastewater treatment applications. Cakes produced by a filter press are always drier and more rigid than those produced by a centrifuge. With regard to maintenance, our experience suggests that centrifuges require more maintenance and are more expensive to maintain than filter presses, typically. In addition, centrifuges (and belt filters) tend to require higher dosages of chemical conditioning than filter presses.

Contact us to explore whether a filter press is right for your application whether biopharma, chemicals, petrochemicals, mineral processing, metals recovery, recovery from e-waste, food processing, and more. Our presses are customized to your specific requirements and can handle a wide range of feed conditions and concentrations.

Filter Cloth

How do I change-out filter cloth for my gasketed, recessed plates?

Micronics has developed two brand new how-to videos to assist you with best practices for installing and removing filter cloth on your recessed, gasketed filter plates.

You can view each of these videos directly on YouTube:

How to properly install Filter Cloth on CGR Filter Plates

How to properly remove Filter Cloth from CGR Filter Plates
Or, you can view these and other helpful videos under our Video Resources.

Contact us to learn more about our filter cloth, plates, presses, spare parts, and services.

How do I change-out filter cloth for my non-gasketed, recessed plates?

Micronics has developed two brand new how-to videos to assist you in best practices for installing and removing filter cloth on your non-gasketed (“NG”) recessed, filter plates.

You can view each of these videos directly on YouTube:

How to properly install Filter Cloth on Non-Gasketed Recessed Filter Plates

How to properly remove Filter Cloth from Non-Gasketed Recessed Filter Plates

Or you can view these and other helpful videos in our Video Resources.

Contact us to learn more about our filter cloth, plates, presses, spare parts, and services.

Can I wash filter cloths with a portable high pressure washer?

Yes, provided the hose has a fan and not a needle tip. The wand should be moved over the filter cloth consistently and not held in one position. 800 to 900 psi is probably an adequate pressure to clean cloths. If cleaning is not efficient, then consider chemically removing embedded particulates.

Can I chemically clean my filter cloth?

Chemical cleaning of filter cloth is a very effective way of rejuvenating filtration performance. Polypropylene cloths will accept both caustic and acid cleaning whereas nylon and polyester fibers require more careful selection of the cleaning medium – contact us for help. REMEMBER – Precautions must always be taken when handling chemical cleaning solutions.

How do I extend my cloth life?

Cloth life is shortened by mechanical damage, which may be caused by chemical attack, mechanical abrasion, or both. Life is also shortened when cloth becomes blinded. Write down all the filter press operating conditions, and in particular changes that you have made, and forward them to us for evaluation and recommendations. We have a questionnaire for this purpose.

Contact us to explore ways of extending your filter cloth lifetime!

How long may I store filter cloth?

Micronics’ synthetic cloths may be stored indefinitely; they are not affected by mildew or insects. Ultraviolet light will weaken polypropylene and these cloths should be stored inside.

Do you provide a micron rating for your filter cloths?

No, filter cloth specs are not provided with a specific micron rating. The terminology in the fabric manufacturers & filter cloth world is the material’s permeability. The unit of measure for these specifications is “CFM” or cubic feet per minute, which refers to cloth permeability. CFM numbers vary considerably depending upon textile type (woven vs. felt), material of construction, filament type, fabric weight, and other parameters. Our specifications include a permeability number (in CFM).

Here’s a useful tip if you are concerned about micron ratings: Once you develop a thin layer of filter cake in your filtration application, the filter cake actually becomes the true filter, often filtering down to one micron at that point.

Please contact us to discuss cloth specifications for your particular filtration application.

How can I tell if my filter cloth needs replacing?

Filter cloth that has performed well – indicating that it was the correct design for your conditions – will eventually have to be replaced. Usually, when filter cloth needs replacing, you will observe that the filter cycle times will be longer and the filter cake will become progressively wetter. If your cloth has not performed well from the start, then you need to modify the design.

Contact us so that we may assist you in selecting the right filter cloths for your operating conditions.

Can I try samples to see if they work?

We will provide a small number of filter cloth samples at no charge for initial evaluation. It is usual for us to require some information on the operating conditions and your goals prior to making filter cloth recommendations. Micronics has deep expertise in filter cloth selection for a wide variety of applications, including for new and emerging fields! Contact us to request a filter cloth sample today & let us help you optimize your press operation.

How long do filter cloths last?

Filter cloth life depends on a variety of factors including your specific process or application, how often you run your filter press, what you run through your filter press, and how well you maintain your filter cloths. If you are seeing things like holes, folding, stretchiness, abrasion, sloppy cake, poor cake release and/or a dirty filtrate – or where standard chemical cleaning does not rejuvenate filtration performance – it is probably time to change your cloths. Contact your Micronics sales representative or inside sales representative to reorder filter cloth to ensure optimal press performance.

Filter Plates

Can I change the type of filter plate I have?

Yes, any type of filter plate may be retrofitted to any filter press. You must only adhere to the maximum operating pressure of the filter press frame.

Why does my filter leak around the edges of the plates?

The filtration characteristics of specific slurries will affect filtration efficiency and having too much back pressure will result in edge leaking. Poorly-designed filtrate discharge piping, higher than recommended pumping volumes, or incorrectly selected filter cloths may all cause or contribute to this problem.

How can I buy spare filter press plates?

A questionnaire is available to help fill in the correct dimensions. Filter plates are custom made for the particular brand of filter you have. We can manufacture plates to the correct specification for any brand, make or model of filter press. Contact us to ensure that you have a proper inventory of spare filter press plates for your operation.

What Is A Mixed Pack Membrane set?

A Mixed Pack Membrane set is a filter plate set that consists of alternating Membrane and Recessed Chambered or Companion Filter Plates. Learn more about the benefits in this blog content.

What is a replacement membrane?

It is a Membrane Plate type in which the membrane is mechanically fixed to the plate. And, the Membrane skin can be replaced while keeping the original body plate, delivering cost-savings to you. Learn more about Replacement Membranes as well as Fixed Membrane Plates here.

What are three way filtrate valves?

Three Way Filtrate Valves are used on filter plates to isolate the chamber, sample the filtrate for testing, or to operate the filter plates in closed delivery mode (e.g. internal discharge through corner ports connected to  a feed end manifold).

Three Way Filtrate valves may also be installed at random positions along a closed delivery filter press pack in order to isolate the location of a filter cloth tear/break, which may be resulting in a cloudy, non-clear filtrate. A common frequency for this sort of test is every five plates. Whenever increased filtrate solids are seen, a quick check along the filter pack length – opening and closing a valve to examine the filtrate – can easily isolate the offending chamber to allow for quick filter cloth replacement.

While this type of valve is not easily retrofitted on existing plates without careful preparation, it is a simple task to add new filter plates with the 3 Way Valves already fixed. This is a relatively inexpensive investment, particularly where your cake solids have high value.

Contact us to discuss Filter Plate selection and 3 Way Filtrate Valves.

What are one-button and three-button filter plates?

Filter Plate Sequencing is an important part of ensuring excellent filter press performance for plate packs employing Air Blow or Wash Sequences. Proper filter plate sequencing involves alternating the sequence of “1-Button” and “3-Button” Filter Plates or 1-3-1-3-1-3 Sequencing. The 1-Button and 3-Button Filter Plates denote different porting. If filter plates need to be replaced, it is important to ensure that the 1-3-1-3-1-3 is properly maintained.

Contact us for assistance with all things related to filter plates, filter cloth, and the proper maintenance of your filter press for optimal performance.

What is open filtrate discharge?

Open Discharge is where the filtrate is discharged externally to the filter plate with no drain eyes in the corners of the filter plate. The filtrate will drain into an open trough (launder) running the length of the Filter Press. The big advantage is the easy visual identification of a failed filter cloth – that plate will run dirty when compared with the others. Learn more about our Recessed Filter Plate options here.

What is closed filtrate discharge?

Closed Discharge is where the filtrate is discharged internally to corner drain eyes. In this design, all of the filtrate goes to the feed end of the filter press, ideal in instances where the filtrate needs to be contained due to pH or odor. This configuration is required in instances where the filter cake needs to be washed or air-dried. Learn more about our Recessed Filter Plate options here.

Service & Filtration Process Optimization

Can I reduce my cycle time?

Normally the slurry characteristics determine cycle time. Conditioning of the slurry can improve the dewatering time. Thinner cakes will also reduce cycle times and are more easily washed.

Can I arrange for a service call to refurbish my filter at my facility?

Yes, we can arrange for service technicians to visit your operation to conduct the refurbishment work on site. In many cases, it is possible for Micronics to supply parts that may easily be installed by your personnel, saving you money. Examples of this include replacement polypropylene filter plates, hydraulic systems, control panels, and automatic and semi-automatic plate shifters. Consult with us about a service and spare parts strategy that makes sense for your needs to optimize your press operation.

Contact Our Experts

Micronics, now a part of Cleanova, is your trusted partner for engineered filtration solutions. We offer end-to-end solutions from filter media to industry-leading filtration equipment, to spare parts & accessories, to on-site field services and in-house laboratory services. Whether for your Filter Press, Belt Press, Leaf Filter, Vacuum Filter, or Baghouse, you can count on Micronics’ deep industry and applications knowledge for the right engineered filtration solution to meet your needs. We look forward to working with your team.

Contact us to discuss your requirements of Horizontal-Shaft Axial Flow Pump. Our experienced sales team can help you identify the options that best suit your needs.

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