Types of Filter Plates

There are three basic categories of filter press plates: recessed chamber, membrane squeeze (diaphragm squeeze) and plate and frame. Continue reading to learn the differences between each type of design.

Recessed Chamber Filter Press Plates

cgr-recessed-chamber-filter-plates
Gasketed (CGR) Filter Plates

These filter plates are utilized in various brands of recessed chamber filter presses, and represent the most commonly used plate.

  • The filter plates are stronger and have a higher fill pressure than plates and frame
  • Gasketed, virtually leak free (CGR)
  • Allows for mechanical plate shifting
  • Non-gasketed available (NG)

CGR vs. NG Filter Plates

“CGR” is an acronym for “Caulked, Gasketed, Recessed chamber.” CGR filter plates should provide a virtually leak-proof filter press. Filter cloths for these plates are octagon shaped, with a caulking rope or cord sewn into the edge of the cloth.

“NG” means “Non-Gasketed.” The NG cloth is faster and simpler to install, though the tradeoff is that occasionally some dripping can happen when using NG cloths.

To learn more about filter cloths, take a look at this blog post.

CGR filter plate in press; Recessed filter plates; Recessed Plate Filter Press
Caulked, Gasketed, Recessed Chamber (CGR) Filter Plate in Press
NG filter plate in press; Recessed filter plates; Recessed Plate Filter Press
Non-Gasketed (NG) Filter Plate in Press

Membrane Squeeze Filter Plates (Diaphgragm Squeeze)

M.W. Watermark Membrane Filter Press Plates; Membrane Squeeze Filter Press Design

These filter plates are utilized in a membrane squeeze filter press and are designed for unique applications. This type of plate is also more costly than recessed chamber plates. Using diaphragm/membrane squeeze filter press plates may result in significant additional fluid removal and/or cycle time reduction if the filter cake is compressible.

M.W. Watermark Membrane Filter Press Plate; Membrane Squeeze Filter Press Design

These are considerations that our Sales and Service Team keeps in mind when recommending membrane squeeze plates:

  • The filter cake is compressible
  • Slurry has higher than average solids
  • Time is money – the time saved by the squeeze justifies more expensive equipment
  • The slurry has variable volume
M.W. Watermark Membrane Squeeze Plate with Replaceable Diaphragm; Membrane Squeeze Filter Press DesignM.W. Watermark Membrane Squeeze Plate with Replaceable Diaphragm; Membrane Squeeze Filter Press
Membrane Squeeze Plate with Welded Diaphragm

M.W. Watermark Membrane Squeeze Plate with Replaceable Diaphragm; Membrane Squeeze Filter Press
Membrane Squeeze Plate with
Replaceable Diaphragm

In a typical filter press application, approximately 80% of the solids are pumped into the press in the first half of the cycle, with the remaining half considered the consolidation stage. With membrane squeeze, the cycle is shortened and the cake moisture content is reduced (see chart).

diaphram squeeze filter press plates - graph, diagram; membrane squeeze filter press

The result is increased throughput and better liquid recovery. Adding membrane squeeze to a filter press requires a specialized plate stack, a squeeze water manifold, and a filter plate pressurization system. Typically, membrane plates are alternated with standard chamber plates in a “mixed pack” as shown in the photo below.

membrane-squeeze-filter-press; membrane filter press design

Contact M.W. Watermark to discuss which type of membrane squeeze plate may be best suited for your particular application. If chemical compatibility is a concern, various materials of construction are available for replaceable diaphragms, including EPDM, NBR, Viton, and more.

Plate and Frame Filter Press Plates

plate-and-frame-filter platePlate and frame is the oldest of the filter plate designs, but is still useful in certain applications.

  • Used for fine filtration where filter paper may be required
  • Allows for different filter cake thicknesses by adding a thicker or thinner frame
  • Filter cloth drapes over plate
  • You should expect some leakage
  • Operated at lower pressures
  • Applications:
    • Polishing
    • Specialty chemicals
M.W. Watermark Plate and Frame Filter Press
M.W. Watermark Plate and Frame Filter Press

Contact our Sales and Service Team to learn more or request a quote today.

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About M.W. Watermark

M.W. WATERMARK wants to make a difference. We are passionate about the world’s water. We are innovative, focused on customer service and always try to exceed expectations. We are an environmentally conscious company with people who are energized, encouraged and inspired to make a difference on our planet by helping to keep our shared, finite water supply clean and usable for generations to come. We build amazing, custom water and wastewater treatment equipment. Together, we can make a difference.

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Types of Filter Plates
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2 thoughts on “Types of Filter Plates

  • August 19, 2014 at 9:44 am
    Permalink

    do you ever use silicone sponge for filter plates?

    Reply
    • August 20, 2014 at 8:30 am
      Permalink

      Mike, our gasketing is most frequently made of EPDM. For chemically abrasive or very high temperature applications, we use Viton. Filter plates are typically made from polypropylene. This is low cost and not very compressible.

      Reply

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