Pressing Onward: A Dewatering Blog

Semi-automatic vs. Fully Automatic Plate Shifting

By Michael Stock


Plate shifting. It's absolutely necessary to keep dewatering systems up and running and filter presses "pressing onward". At the end of each and every filter press cycle, the plates are separated (or shifted) so the filter cake can be discharged from the press. Plate shifters controlled by the hydraulics of the press, make this process possible.

Much like the transmission of a car, filter press plate shifting can be controlled with some help from the operator (semi-automatic shifting) or with no help from the operator (fully automatic shifting). Read on to learn more about these 2 types of plate shifting and find out which type might be the best fit for your dewatering process.


Semi-automatic Plate Shifting

As the name implies, this type of plate shifting is able to perform the shifting action on its own and some has to be performed by the machine operator. The whole process looks a little something like this:

  1. The operator rolls the semi-automatic shifter into position
  2. The shifting process is activated when the operator presses a control switch
  3. The plate separator pneumatically lifts between the filter plate handles
  4. The plate is then pushed away from the filter pack, allowing the filter cake to fall
  5. The separator returns and the operator moves the shifter on to the next plate

Since this type of plate shifting does require the attention of a machine operator after every press cycle, it can be a good fit for -

  • Dewatering processes that deal with small batches of slurry or where the filter press isn't run very often.
  • Applications where operator supervision is desirable like wine or cider making.
  • If the slurry that is being dewatering is particularly stubborn and needs a little help being removed from the filter cloths.



Fully Automatic Plate Shifting

Many of our larger filter presses are outfitted with a fully automatic plate shifter. There are 2 types of automatic shifters that differ slightly in their operating process, they are best described as automatic pry & shift and automatic pry, bump and weigh.

Automatic Pry & Shift

This type of plate shifting automatically cycles through the filter plates, separating each plate to release the cake (and allow for cloth washing if needed). Don't worry about out of order cake discharge. A series of mechanisms ensure that only one plate is shifted at a time and in the proper sequence.

The system isn't just simple when it comes to operation, but also when it comes to maintenance. The components (rails, chains, guards, etc.) are made of corrosion resistant materials that can stand up to even the toughest dewatering applications.

Automatic Pry, Bump & Weigh

This system is a variation on the traditional automatic shifting system. It has 2 additional features. One is an extra component that "bumps" the plate as it is shifting to remove stubborn stuck on filter cakes. The other is a sensor measures the weight of the plate to ensure that is clean and not being weighed down by extra filter cake. With this system you will have the cleanest cloths in town.

Note - this type of plate shifter is great for applications that have slurries that have a high concentration of solids, like mining. Check out the video to see one of our MC PressĀ® filter presses, meant for use in mining applications, in action!


Since these plate shifting systems require no operator attention (except for routine maintenance and repairs) they are a great option for the following:

  • Facilities with large amounts of slurry to dewater.
  • Locations where there are multiple filter presses installed.
  • Applications where operator contact with the filter cake is undesirable. For example, if the slurry being dewatered contains hazardous chemicals and substances.
  • Facilities that are unable to have a dedicated press operator.
  • Various lights-out applications like mining or manufacturing.

Our sales engineers develop each plate shifting system using a building block approach so no matter the application you will be using the press for, they can help you choose a system that will be a great fit.

Are you interested in updating the plate shifting system on your filter press that is made by a company other than Evoqua? Don't worry, we have extensive experience retrofitting our Evoqua plate shifters on other brands of filter presses.

Looking for more ways to improve the performance of your filter press? Download our guide for more dewatering tips, tricks and maintenance advice!

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