In industrial heat transfer applications, the terms pillow plate and dimple plate are often used interchangeably. However, while they share similarities, they are not identical in structure or performance.
This article explains:
What a pillow plate is
What a dimple plate is
The difference between them
The working principle of pillow plate heat exchangers
A pillow plate is a type of heat transfer plate manufactured by laser welding two thin stainless steel sheets together in a specific weld pattern. After welding, the plate is hydraulically inflated, creating a three-dimensional internal flow channel between the sheets.
The inflated structure forms a “pillow-like” shape, which gives the technology its name.
Manufactured from two welded metal sheets
Internally pressurized to create flow channels
High turbulence due to uneven surface
Excellent resistance to fouling
Suitable for high-pressure applications
Pillow plates are commonly used in:
Falling film evaporators
Tank heating and cooling jackets
Immersion heat exchangers
Condensers
Food and beverage processing equipment
A dimple plate is typically made from a single sheet that is mechanically stamped or pressed to create protrusions (dimples). It may also refer to a welded plate without significant hydraulic inflation.
Unlike pillow plates, dimple plates usually:
Have shallower flow structures
Provide lower internal turbulence
Are often used as tank jackets
May not be suitable for high internal pressure
In many markets, “dimple plate” is used loosely to describe pillow plates, but technically, they are structurally different.
The main differences lie in manufacturing method and performance:
| Aspect | Pillow Plate | Dimple Plate |
|---|---|---|
| Structure | Two sheets laser welded & inflated | Mechanically pressed or lightly welded |
| Internal Channel | Formed by hydraulic expansion | Formed by stamping |
| Pressure Resistance | High | Moderate |
| Turbulence Level | High | Lower |
| Heat Transfer Efficiency | Higher | Lower |
| Typical Use | Evaporators, condensers, industrial heat exchangers | Tank jackets, low-duty heating |
In short:
Pillow plates are structurally stronger and more efficient.
Dimple plates are simpler and typically used in less demanding applications.
The operating principle is based on indirect heat transfer between two media separated by stainless steel sheets.
One fluid flows inside the inflated channels of the pillow plate.
The second fluid flows outside the plate or across the plate surface.
Heat transfers through the thin stainless steel wall.
The inflated geometry creates turbulence, improving heat transfer coefficients.
Because the surface is uneven and highly turbulent, pillow plate heat exchangers offer:
High heat transfer efficiency
Reduced fouling tendency
Compact structure
Flexible modular design
They can operate in:
Single-phase heating or cooling
Condensation applications
Falling film evaporation systems
Pillow plate heat exchangers are particularly suitable when:
High pressure resistance is required
Fouling risk is significant
Hygienic design is necessary (food, pharma)
Custom tank integration is needed
Large heat transfer surfaces are required
Although pillow plates and dimple plates are sometimes used interchangeably in conversation, they differ significantly in structure, strength, and performance.
Pillow plates provide:
Stronger construction
Better turbulence
Higher heat transfer efficiency
Greater design flexibility
For demanding industrial applications, pillow plate heat exchangers are generally the preferred solution.
