Filter Press FAQ

Cleaning filter cloths, reducing cycle time and more!

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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.

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.

Contact us to discuss your requirements of Filter Press Belts. Our experienced sales team can help you identify the options that best suit your needs.

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 Is Your Trusted Partner for Total 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.

How to select belt press and filter press?

Belt filter presses and chamber filter presses are the special equipment for separating solids and liquids through filter cloth. Sludge, as the the main material treated, which is coproduct of sewage treatment. The sewage is cleared after treatment and the pollutants are transferred to the sludge.

How to choose the proper model?

Generally, belt sludge dewatering machine is composed of filter belt, roller cylinder, filter belt tensioning system, filter belt deflection system, filter belt washing system and filter belt drive system. When making model selection, the following aspects should be considered:

1. Filter belt. The high tensile strength, tortuosity, acid and alkali resistance, temperature resistance and other characteristics are required. At the same time, the appropriate woven texture should be selected according to the specific properties of sludge, to make filter belt have good gas permeability and interception performance of mud particles.

2. Deflection system of roller cylinder. It is usually done by pneumatic means.

3. Tensioning system of filter belt. It is also generally controlled by pneumatic system. The filter belt tension is generally controlled at -0.3-0.7 MPa, and the usual value is 0.5 MPa.

4. Belt speed control. Different types of sludge have different requirements on belt speed, that is, there is a range of belt speed control for any specific sludge. Within this range, the dewatering system can guarantee a certain processing capacity, and can get high quality mud cake.

Chamber filter press is extruded through the plate frame to make the water in sludge discharged through filter cloth to achieve the purpose of dehydration. It is mainly composed of concave man filter plate, frame, automatic-pneumatic closed system measuring plate suspension system, filter plate vibration system, air compression device, filter cloth high-pressure flushing device and body side photoelectric protection device. When selecting, the following aspects should be considered:

1. The requirement for solid content of mud cake. Compared with other types of dewatering machines, the chamber filter press has the highest solid content. If considering the factors of reducing the land occupation of sludge, the plate and frame filter press can be selected.

2. Frame material.

3. The material of filter plate and filter cloth. Corrosion resistance is required, and the filter cloth must have a certain tensile strength.

4. How the filter plate moves. The requirements can be fully or semi-automatically completed by hydraulic-pneumatic devices to reduce the labor intensity of operator.

5. The filter cloth oscillates device to make filter cake easy to fall off. Compared with other types of dewatering machines, the biggest disadvantage of filter presses is that they have a large footprint.

Realted article: Belt press vs Filter press

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