JWI Filter Press Engineering Guide

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A filter press is a batch dewatering device that separates solids from liquids using pressure filtration.

A typical JWI filter press consists of:

• Hydraulic closing system
• Headstand
• Tail stand
• Sidebars
• Filter plates
• Filter cloths
• Center feed piping
• Corner discharge manifold
• Air blowdown system

The hydraulic cylinder closes the plate stack while slurry is pumped into the press. Solids accumulate within each chamber while filtrate passes through the cloth and exits through the corner discharge ports.

For replacement components, visit our JWI Filter Press Parts page.

Most JWI model numbers follow a simple format:

Plate Size – Gasket Style – Cake Thickness – Number of Plates – Cubic Foot Capacity

Examples:

470G-32-5-1

1200NG-32-83-100

The model number immediately identifies the plate size and overall filter press volume.

For a complete breakdown of model numbers, see our JWI Model Number Guide.

The hydraulic system is the heart of every JWI filter press.

Its responsibilities include:

• Closing the plate pack
• Maintaining sealing pressure
• Preventing leakage during filtration
• Opening the press after the filtration cycle

Many original hydraulic power units are now over twenty years old and are increasingly difficult to repair.

Common hydraulic issues include:

• Low closing pressure
• Hydraulic oil leaks
• Worn seals
• Obsolete electrical controls
• Failed hydraulic pumps

Most JWI hydraulic systems use ISO 46 hydraulic oil.

For replacement systems, see our JWI Hydraulic Pump and Power Unit page.

One of the most common leak points on older JWI presses is the center feed pipe.

These pipes carry slurry from the feed manifold into the plate stack.

Over time operators often experience:

• Hairline cracks
• Thread damage
• Corrosion
• Wear at connection points

Even a small crack can allow slurry to bypass the filtration chamber and create leakage around the head plate.

Replacement center feed pipes are available in PVC, CPVC, carbon steel, 304 stainless steel, and 316 stainless steel.

Proper cloth selection dramatically impacts filter press performance.

Factors engineers should evaluate include:

• Particle size
• Desired filtrate clarity
• Cake release requirements
• Chemical compatibility
• Temperature

Incorrect cloth selection often causes:

• Cloudy filtrate
• Wet cake
• Slow cycle times
• Frequent cloth cleaning

Our engineering team can help identify replacement cloths based on your process requirements.

Many larger JWI presses include corner-port air blowdown systems.

The purpose of the blowdown system is to:

• Remove trapped slurry
• Clear discharge manifolds
• Improve cake dryness
• Reduce carryover into the filtrate system

Properly functioning blowdown systems can significantly improve overall dewatering performance.