Hydraulic Systems

Depending on the size of your filter press, M.W. Watermark™ offers three hydraulic options:
  • Electric
  • Air
  • Manual

Parts and retrofits are also available for existing units.

Learn More on Our Blog…

“M.W. Watermark™ Now Offers Rebuild Kits for Filter Press Hydraulics” – Learn more.

“New and Improved: M.W. Watermark™ AFPCS” – Learn more.

“Troubleshooting Your Filter Press Air Hydraulic System”Learn more.

“Air-Operated Filter Press: Setting Hydraulic Relief Pressure”Learn more.  

“Choosing the Right Hydraulic System and Controls for Your Filter Press” – Learn more

“M.W. Watermark Filter Press Air-Operated Hydraulic System” – Learn more

“M.W. Watermark Retrofit Hydraulic Power Unit (HPU)” – Learn more

Electric Hydraulics

Electric powered hydraulic pumping units maintain the hydraulic pressure and if the pressure exceeds the relief setting this pressure is vented keeping the pressure within the specified range.

For press sizes 800mm through 1500mm, electric hydraulics are optional to decrease filter press opening and closing times. For added operator and equipment protection, the hydraulic power unit (HPU) is enclosed within the leg of the filter press that supports the hydraulic cylinder. The HPU includes a high volume / low pressure pump to open and close the plate stack quickly and a low volume / high pressure pump that clamps the plate stack. Once the plate stack is closed, the high pressure hydraulic pump clamps the plate stack with a force, plus a safety factor, to counteract the pressure of slurry feed.

Electric hydraulics are controlled by the M.W. Watermark Electric Hydraulic Control System (EHCS), which monitors the status of the system and provides an emergency stop push button, disconnect switch, and touch screen control of the filter press hydraulics.


1200mm with Explosion Proof (opt.) Electro-hydraulics


1500mm with Electro-hydraulics

Air Powered Hydraulic Pump

Air powered hydraulic pumping units convert plant air to hydraulic pressure through a simple ratio system that uses a large air piston area at low pressure to produce a high hydraulic pressure on a small area hydraulic piston. Automatic reciprocation is controlled by the action of a pilot operated selector valve in the pneumatic section of the pump.

As the hydraulic output approaches the desired pressure dictated by the air pressure regulator setting, the pump slows down and finally stalls when the hydraulic force balances the air force. Hydraulic force is maintained with no consumption of power.

For filter press sizes 630mm through 1000mm, air hydraulics are included as standard. For added operator and equipment protection, the hydraulics are enclosed within the leg of the filter press that supports the hydraulic cylinder. 100 psi air is used to pressurize an oil reservoir that is used to push the plate stack closed.

Once the plate stack is closed, a high pressure air-operated hydraulic pump clamps the plate stack with a force, plus a safety factor, to counteract the pressure of the slurry feed. When the cycle is complete, the air-operated hydraulic system releases the pressure within the cylinder and uses air pressure to retract the follower for filter cake discharge. The air hydraulic control switches and gauges are mounted in either the left or right hand side of the leg of the filter press to suit the installation.

M.W. Watermark has updated its standard air hydraulic design from a modular-style design to a manifold block. There are many short-term and long-term benefits to a manifold block hydraulic design:

  • A manifold block is more compact and has fewer fittings and components. Updating this system lowers the risk of potential leaks.
  • The filter press opens and closes significantly faster. The 630 mm press opens 47 seconds faster and closes 18 seconds faster.
  • The manifold block is easier to service.

All new M.W. Watermark air hydraulic filter presses utilize manifold block hydraulics.

M.W. Watermark Filter Press with Upgraded Air Hydraulics and Optional AFPCS Filter Press with Upgraded Air Hydraulics and Optional AFPCS

M.W. Watermark Manifold Block Air-Operated Hydraulics - Inside the Hydraulics CabinetInside the Air-Operated Hydraulics Cabinet

The M.W. Watermark filter press air-operated hydraulic system has been designed for durability, longevity and quick closing, clamping and opening times. Click below to watch our video and learn more.

Manually Operated Hydraulic Pump

The hydraulic cylinder is swung from the “up” to the “clamp” position and the hand pump is operated to build clamping pressure. At the end of the dewatering cycle, the hydraulic pressure is released and the cylinder is retracted by an internal spring. The cylinder is then lifted to the “up” position and the follower is manually pulled back to the end of the press. The filter plates are then manually shifted to discharge filter cake.

To eliminate hand pumping, an air-operated single-acting closure system (close only) is available as an option.

How to Open/Close a Manually-Operated Hydraulic Filter Press


Manually Operated Hydraulics, cylinder raised


Hydraulic Cylinder


Opt. Air-Operated Hydraulic Pump


Opt. Air-Operated Diaphragm Pump

hydraulic control system

Retrofit Hydraulic Power Unit (HPU): 7 or 11-gallon
Product Number: 40018742
Download Brochure

Hydraulics & Controls

M.W. Watermark stocks parts for hydraulic systems and controls. Retrofits are available for used filter presses.

Download our Hydraulics Rebuild Kits Brochure
Contact us for a quote

Hydraulic Module
Product Number: 40001262W


Air Module


Hydraulic Module
Product Number: 40000380


Air Module
Product Number: 40000398


Control Parts – Gauges & Switches

2 gauge control panel

Control Panels