Types of Filter Plates
There are three basic types of filter plates: recessed chamber, plate and frame, and diaphragm squeeze. Continue reading to learn the differences between each one.
Recessed Chamber Filter Plates
Recessed chamber plates are 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 trade off is that occasionally some dripping can happen when using NG cloths.
To learn more about filter cloths, take a look at this blog post.
These filter plates are designed for unique applications and are more costly than recessed chamber plates. Using diaphragm squeeze filter plates may result in significant additional fluid removal and/or cycle time reduction if the filter cake is compressible.
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 diaphragm squeeze, the cycle is shortened and the cake moisture content is reduced (see chart). The result is increased throughput and better liquid recovery. Adding diaphragm squeeze to a filter press requires a specialized plate stack, a squeeze water manifold, and a filter plate pressurization system. Typically, diaphragm plates are alternated with standard chamber plates in a “mixed pack” as shown in the photo below.
These are considerations that our Sales and Service Team keeps in mind when recommending diaphragm 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
Plate and Frame Filter Plates
- Used for fine filtration where filter paper may be required
- Filter cloth drapes over plate
- You should expect some leakage
- Operated at lower pressures
- Specialty chemicals
*** Our Capital Equipment Sales Team is happy to questions you may have about the appropriate filter plates for your application.
Already have a filter press? We also stock a variety of filter plates for aftermarket sale. Contact us at 616.399.8850.
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