Sequencing Your Filter Plates

Extend the life of your M.W. Watermark™ wastewater treatment equipment by correctly sequencing your filter plates

For your wastewater treatment equipment to create the best filter cake formation during a filtration cycle, your filter plates need to be properly sequenced in your filter press. This allows all four corners of the chamber to drain. Having plates out of sequence only allows drainage from one side of the chamber. This will produce sloppy, sticky cakes instead of firm, fudge-like slabs.

Poor Quality Filter Cake
Sloppy, porridge-like filter cake. This is not good!

Proper plate sequencing is referred to as 1-3-1-3 sequencing, which involves alternating the #1 and #3 filter plates. The difference between #1 and #3 filter plates are where they’re ported. You can read more about that below.

A tip from our Sales Team

Once your filter plates are in the right order, number them starting with your head plate to the tail plate (1-…). This keeps them in the correct order and helps you easily identify any potential issues (leaky plates).

Numbered Filter Plates
Filter plates numbered in press

Filter Plate Porting

M.W. Watermark™ wastewater treatment equipment includes a minimum of four variations of filter plates in any given filter press:

  1. Head Plate: This is a #1 plate and is the closest plate to the manifold; you will not be able to pull this plate away from the steel frame, unless you have a connection plate.
  2. Tail Plate: This plate indicates the end of the plate stack.
  3. #1 Intermediate Plate: These filter plates are noted with a single dot on the plate. They are ported in the right hand corners (from piping end of press).
  4. #3 Intermediate Plate: These filter plates are noted with three dots lined up vertically on the plate. #3 plates are ported in the left hand corners (from piping end of press).
  5. Optional Blanking Plate: Learn more about how a blanking plate functions by reading this  article.

**For non-gasketed filter plates, #1 and #3 plates can be identified by the color of the cloth dog pins, or by the number of dimples on the side of each plate.

Filter Plate - Head Plate Ported
Head Plate
Filter Plate - Back of Tail Plate
Tail Plate
Filter Plate - #1 Intermediate Filter Plates Ported, Arrows Showing Ports
#1 plate ports (there are also ports under the cloths you cannot see)
L-R; Tail Plate, Ported #3 Plate, #1 Plate
L-R; Tail plate, ported #3 plate, #1 plate.
1 Plate and 3 Plate in Pres-No filter Cloth
Porting on the face of #1 and #3 intermediate filter plates.

The filter plates are ported this way because it forces air or fluid (depending on the operation) to fill up the entire chamber of plates from top to bottom, front to back.


Filter plate sequencing is also imperative to post-filtration operations, such as air blow. The air blow of the filter cake is performed to remove filtrate from the filter cake and residual filtrate from the filter pack porting connections prior to cake discharge. Pressurized air is introduced into the upper left filtrate discharge port, forced through the cloth and filter cake in each chamber and out of the lower right discharge port. This effectively purges your wastewater treatment equipment of buildup.

  • The #3 plate has discharge ports on the top & bottom left hand side of the plate and air is only allowed to enter into the upper left hand discharge eye (from piping end of press).
  • The air can only get into the #3 plate, since this is the plate with discharge ports on the left.
  • The air will split and go into the chamber on either side of the #3 plate.
  • The air must travel completely through the cake from the top left to the bottom right.
  • The air exits the bottom right of the #1 plate (because this is the only exit valve open and the #1 plate has discharge eyes only on the right hand side).
1-3-1 Filter Plate Sequence
1-3-1 Filter Plate Sequence

The removal of excess filtrate will improve cake dryness and help loosen the filter cake for improved cake release. If you don’t get a good air blow, you’ll get water running out of your plates when you open your filter press.

If you have any questions about filter plates, contact our Sales & Service Team at 616.399.8850.

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M.W. Watermark is a trademark owned by M.W. Watermark, L.L.C. All rights reserved.
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