5 Things to Know Before Buying Chamber/Recessed Filter Plate

19 May.,2025

 

Plate and Frame Filter Press vs Recessed Plate Filter ... - Met-Chem

Filter Press Diaphragm Pumps

Filter Press Diaphragm Pumps

Air operated diaphragm pumps are used with filter presses to pump sludge from the bottom of the sludge holding tank into the filter press.  These pumps are ideal because they can handle the slurry which is generally about the consistency of a milkshake.

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The diaphragm pump usually starts out slowly and gradually ramps up.  Once the pump starts to slow back down, (30-60 seconds between thrusts), it is usually an indicator that the filter press is full.  At this point, the feed pump should be turned off and the valves on the filter press closed as the operator prepares to operate the air-blow-down process.

The diaphragm pump can be manually turned up or an Automatic Pump Control system may be added.  This starts the pump at 25 psi, then moves up to 50, 75 and finally 100 psi which is standard operating pressure for the pump.

Met-Chem provides diaphragm pumps in the following sizes:  1”, 1.5”, 2” and 3”.  The material of construction ranges from cast iron, aluminum, polypro or stainless steel.

With the purchase of a new Met-Chem filter press, Met-Chem can mount your air operated diaphragm pump to the legs of your filter press.  This option also includes a flex hose that connects the outlet of the diaphragm pump to the center feed pipe, an air filter, a regulator, and an oiler.   We can also provide a mounted diaphragm pump for your existing press.

Automatic Filter Press Pump Control System

Automatic Filter Press Pump Control System

The Met-Chem Automatic Pump Control System is used in conjunction with an air operated diaphragm pump to automatically increase the feed pump pressure at predetermined intervals during the filter press filling cycle.  If the pump runs at a higher initial pressure, the filter cake will become a packed layer of solids on the filter cloth.  This will restrict the flow of the slurry thereby creating a very dense coating of the filter cake.  This can cause the cloths to blind off and not allow further filtration.  Starting at a lower feed pressure allows a soft layer of slurry particles to be deposited on the filter cloth.  This initial layer becomes the filtering media which will enhance the filterability of the incoming slurry.

The automatic pump control system automatically and gradually increases the feed pressure in four stages during the filling cycle.  These stages are adjustable to suit your slurry and solids concentration.  However, it is commonly set at increments of 25 psi.  (25, 50, 75, 100).  By monitoring the feed pump flow sensor, during the final pressure stage, the operator will be able to determine the cycle completion.

The Automatic Pump Control System also incorporates a low hydraulic pressure safety shut down the device.  If there is not enough hydraulic clamping pressure present, the system will completely shut down, eliminating any possible leaking from between the filter plates.

The pump control system allows your filter press to run at its optimum efficiency creating dryer filter cakes, reducing disposal costs, reducing operator time and increasing the life of your filter cloths and feed pumps.

This system can be incorporated with a new filter press from Met-Chem, a used unit or even your own existing press.

Spare Parts Kit

Spare Parts Kit

Met-Chem is pleased to offer our spare parts kit which includes our 5 piece center feed pipe assembly, a head, tail, and 2 intermediate filter press cloths, and 100 foot of gasketing material.  These are essential items for the operation of the filter press. A cracked pipe, ripped cloth, or torn gasket can happen anytime and having these items in your stock will ensure you will be back up and running in no time.

Center Feed and Manifold Filter Press Upgrades

Filter Press Center Feed and Manifold Upgrades

A center feed pipe assembly on a filter press should be able to last many years the same way any other type of plumbing will. However, if the material of the center feed pipe assembly is not strong enough to handle the corrosiveness of the solution running through the press then the center feed pipe assembly can corrode. 

For cases of corrosive material or high temperatures, Met-Chem is pleased to offer upgrades from our standard center feed pipe and manifold.  We are able to upgrade to CPVC, Carbon Steel, 304 or 316SS Stainless Steel, and Titanium. Met-Chem can also provide additional manifold upgrades such as automatic valves

The center feed pipe is what connects the filter press to the product that needs to be filtered. The center feed pipe assembly consists of five different parts. The first part is the lock nut which fastens on the center feed pipe and connects to the outside of the press. The pipe, which is the second part, goes through the head of the filter and all the way through the head plate of the filter press. The third part of the center feed pipe assembly is a gasket which ensures the assembly is watertight. Next, is the clip nut seat which fastens the assembly to the head plate. This part of the assembly will always stay in place unless you are replacing the assembly or one of its parts. The final part, the cloth clip nut, will be removed often as it is screwed into the cloth clip nut seat after the head cloth is put on the head plate. The cloth clip nut needs to be tightened in order to keep the cloth in place. Met-Chem provides a tool to make this process easier. The Met-Chem Spanner Wrench is a specially designed tool that can be used to loosen and tighten the cloth clip nut when changing the head cloth on a filter press. This tool can be very helpful as the cloth clip, but it has a design that requires a unique tool to tighten and loosen it.

Longer Legs and Filter Press Sludge Disposal Chute

Longer Legs and Sludge Disposal Chute for Filter Presses

Met-Chem can provide longer legs and a disposal chute on your new filter press.  This is especially useful if you are releasing the sludge from the press into a sludge bag or a drum.  The chute will direct the sludge directly into your container.  If you plan to use a sludge disposal bag, we can add hooks to the chute so that the sludge bag can be hung from the frame of the press.

For some larger presses, we can build a catwalk along with the disposal chute in order to accommodate a roll-off container.

Sludge Dumpster

Filter Press Sludge Dumpster

Sludge Dumpsters are used directly under the filter press to catch the sludge that is released from the filter press during cleaning.  The dumpster is on casters for easy mobility.  They are also equipped with forklift slats for convenient use with a tow motor.  The operator can move the dumpster to a roll-off container with the forklift and then pull the release pin for easy emptying.  The dumpster can then be snapped back to the upright position and put back under the filter press.

Backer Plate for Smaller Filter Press Batches

Filter Press Backer Plate for Smaller Batches

If you produce varying size batches of wastewater and subsequently less sludge, or if the overall volume of waste that is generated at your facility has been reduced, you can still utilize your existing filter press.  With the purchase of a backer plate, you can alter the holding capacity of your press to meet your individual batch needs. 

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A backer plate provides support to the tail plate so that it can be moved anywhere in the plate pack in order to isolate the chambers between the feed end and the tail plate.  If you try to use the tail plate in a different position in the plate pack without the backer plate, you run the risk of damaging the chamber of the tail plate. 

There are different kinds of backing plates.  Some are made of plastic and look much like a standard plate; we prefer to use ~3/8” thick flat stock steel and cut an outline of a plate.  This is clearly visible when placed in the stack so that all around know that the filter press is not at full capacity.  This steel backing plate is then painted with the same two-part epoxy coating as the frame of the filter press.

Filter Press Plate Shifters

Filter Press Plate Shifters

Our standard filter presses can be operated manually. However, Met-Chem manufactures four types of filter press plate shifters to make operating your filter press easier, safer and more efficient. Manual filter presses require more time and attention than the same filter press with an automatic plate shifter.
  • Semi-Automatic
  • Pendant
  • Fully Automatic
  • Super Shifter
For some larger presses, we can build a catwalk along with the disposal chute in order to accommodate a roll-off container. Start-Up Assistance / Installation

Start-Up Assistance/Installation

The start-up and installation options are available with all Met-Chem waste treatment equipment.  We can provide full support as you get your system up and running.  We have installation technicians and technical representatives that we can send to your facility to make sure the system is running as it should based on the engineering and design.

Our services include but are not limited to:

  • Design and build the equimpent per your specs
  • Load, ship, and unload equipment
  • Install and rig equipment in facility
  • Electrical and plumbing connections
  • Train employees
  • Debug any issues and solve any equipment/installation troubles

All units and systems are complete with manuals and support.  However, if you need someone to come to your facility, we will be happy to quote you on that as well. 

Learn more about our Start-Up Assistance and Installation

Choosing a Filter Press - ErtelAlsop

Plate Size
Once the cubic foot capacity of a filter press has been determined the next step is, the proper selection of the size of the filter plates, frame, components and any accessories.  This will allow you to see exactly where the cu. ft. capacity fits in relation to the volume of each size press. For example a 5 cu. ft. can be sized as a 470 mm, a 630 mm and also an 800 mm. The size selected is determined by the amount of expandability desired. After the plate size is selected, there are many options from which to choose. The following information is a summary of what needs to be considered in order to make the proper selection, Please read each section in turn and note your requirements.

Plate Construction
Select the type of filter plate material. The standard material is an industrial grade polypropylene. An optional FDA approved food grade polypropylene material, or a high temperature glass filled polypropylene material are also available. Special materials are also available such as Carbon Steel , Stainless steel and Kynar.

Plate Style
The standard is a 100 psi recessed gasketed plate with EPDM seals. Viton seals are available as an option. Also available are non-gasketed plates with quick removal latex edged cloths, where the cloth acts as the gasket. The Non gasketed plates allow for easier change out of the filter cloth, are lower in cost, but are not completely liquid tight during the processing stage.  Special membrane squeeze plates have the ability to expand after the chambers are full to “squeeze” additional process liquid out of the filter cake.  A “mixed stack” of plates will be provided where every other plate will be a special membrane squeeze plate

Optional Backing Plate
If a shorter cycle is desired, when running low volume applications for example, the capacity of the filter press can be temporarily reduced. This is done by moving the follower (tail) plate forward in the plate stack. The backing or “blank plate” is then placed behind the follower plate acting as extra support. The follower plate will not flex or break when used in this manner.

Plate and Press Pressure Rating
The 100 psi design is standard for most dewatering applications and will produce a cake with approximately 30-35% solids. A 225 psi design can be used to provide an increased yield per cycle and depending on the application can increase the solids in the cake to 50% or more.

Cake Thickness
The 32 mm cake thickness is standard. Options include 25, 38 and 50 mm cake thickness. 25 mm would be used for high viscosity (slimy) materials and 50 mm would be used for easily filtered material.

Cloth Type
ErtelAlsop can provide filter cloths in many different materials, weaves, thread styles, and air permeability values resulting in a wide array of performance characteristics. If possible ErtelAlsop would like to receive samples of the process liquid to conduct filterability tests for cloth selection. If testing is not possible then we will furnish our standard polypropylene filter cloth, a monofilament x multifilament, Sateen weave with a CFM<1.0.

Frame Design
All ErtelAlsop frame configurations are sidebar design.  Frames can be designed in Carbon Steel or Stainless Steel.

Volume of Plates/Expansion Spacer
All filter presses are available with optional removable expansion spacer. On presses ordered with a spacer, the first number denotes current plate capacity. The second number in the nomenclature is the maximum capacity the frame will allow.

Discharge/Air Blow-down Piping
The discharge/air blow-down piping is available in either manual or in automatic operation. An optional core blow-down is available to purge the center feed line of residual fluid. Available materials of construction are schedule 80 CPVC, or schedule 40 Stainless Steel.

Feed Style

The feed style can vary for special applications such as pharmaceuticals and some type of food processing. Center feed is standard, however a choice of any corner feed is available.

Automation versus Manual Operation
Manual or semi automatic operation requires input from an operator to start and operation of the filter press, including opening and closing, blow down, plate shifting etc. Fully automated presses require initial start up of operation and then close fill, blow-down, plate shift, discharge and cloth wash is automated. Restarting the press cycle still requires operator input.

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