Free Flow Plate Heat Exchangers are specifically designed for applications involving high-viscosity fluids, fiber-containing media, and fouling-prone process streams. Compared to conventional chevron (herringbone) plates, Free Flow plates feature wide and open channels that significantly reduce clogging risks while maintaining reliable heat transfer performance.
A Free Flow Plate Heat Exchanger is a gasketed or semi-welded plate heat exchanger using a special plate pattern that:
Creates wide flow channels (ALFA LAVAL MA30S, MA30W, T20S, T35S, Wide gap 100S, Wide gap 200S, Wide gap 300S)
Minimizes contact points
Reduces turbulence intensity
Allows solids and fibers to pass more easily
This makes it ideal for industries where conventional plate heat exchangers may suffer from rapid fouling or pressure drop increase.
Wider channels allow suspended particles and fibers to pass without blocking.
Less clogging means longer cleaning intervals.
Higher heat transfer coefficients result in smaller footprint.
Optimized flow distribution ensures efficient heat exchange despite larger gaps.
Free Flow Plate Heat Exchangers are widely used in:
Edible oil cooling and heating
Pulp & paper industry
Wastewater treatment
Sugar processing
Biogas systems
Sludge heating
Marine oil systems
When selecting a Free Flow heat exchanger, engineers should evaluate:
Fluid viscosity at operating temperature
Solid particle size and concentration
Fouling tendency
Acceptable pressure drop
Cleaning method (CIP or mechanical)
Incorrect material selection or underestimating fouling characteristics may lead to premature corrosion or pitting failure.
In high-fouling environments, the wrong plate pattern can dramatically shorten equipment lifetime. Selecting a Free Flow plate design helps maintain stable thermal performance, reduce downtime, and optimize lifecycle cost.F
Free Flow PHEs are suitable for:
Fruit pulp and juice with fibers
Sugar syrup and molasses
Wastewater and sludge
Pulp & paper stock
Biogas digestate
Slurry with soft solids
High-viscosity liquids
They are specifically designed for dirty or particle-containing fluids.
| Feature | Free Flow PHE | Standard PHE |
|---|---|---|
| Channel gap | Wide | Narrow |
| Solid handling | Excellent | Limited |
| Fouling resistance | High | Moderate |
| Heat transfer coefficient | Slightly lower | Higher |
| Pressure drop | Lower | Higher |
| Application | Dirty/viscous fluids | Clean fluids |
Free Flow prioritizes anti-clogging performance, while standard PHE maximizes compact heat transfer.
Channel gap determines allowable particle size:
5 mm gap → particles up to 3–4 mm
8 mm gap → particles up to 6 mm
10–12 mm gap → soft solids and fibrous materials
Hard or abrasive particles require material reinforcement.
Typical handling capacity:
2–5% suspended solids (standard applications)
Up to 8–10% soft organic solids
Mineral solids or sand significantly increase wear.
Higher viscosity fluids require:
Larger channel gap
Reduced flow velocity
Increased heat transfer area
Optimized port diameter
For fluids above 500 cP, thermal calculations must account for reduced turbulence.
Compared to narrow-gap high-chevron plates:
Heat transfer coefficient may be slightly lower
Pressure drop is reduced
Fouling resistance is significantly improved
In real dirty-service conditions, overall long-term performance is often superior.
Common materials include:
304 Stainless Steel
316L Stainless Steel
Titanium
SMO 254
Hastelloy
Material selection depends on:
Chloride concentration
pH value
Temperature
Corrosion risk
For gasketed Free Flow PHE:
Design pressure: 10–16 bar
Maximum temperature: up to 180°C (depending on gasket)
Higher pressure designs require reinforced frames.
Cleaning methods:
CIP (Clean-in-Place)
Manual opening and high-pressure washing
Chemical cleaning
Pressure drop monitoring is the primary indicator for cleaning.
| Aspect | Free Flow | Shell & Tube |
|---|---|---|
| Footprint | Compact | Larger |
| Maintenance | Easy opening | Tube cleaning required |
| Heat transfer coefficient | Higher | Lower |
| Fouling tolerance | Moderate–High | Very High |
| Best for | Fibrous / soft solids | Heavy solids / high pressure |
Free Flow is ideal when compact size and easier maintenance are priorities.
Food & Beverage
Sugar Industry
Pulp & Paper
Wastewater Treatment
Biogas Processing
Chemical Processing
Yes. Custom options include:
Mixed plate packs (Free Flow + standard plates)
Reinforced frame
Special port sizes
Double gasket systems
Hybrid configurations
Customization improves application flexibility.
