The Four Types of Plate Heat Exchangers in the Food Industry

Introduction

Heat exchange is fundamental in the food and beverage industry for processes like pasteurization, sterilization, cooling, heating, and energy recovery. Among the various heat exchangers, plate heat exchangers (PHEs) are particularly popular due to their compact design, high thermal efficiency, and ease of maintenance. There are four main types of plate heat exchangers used in the food industry:

Gasketed Plate Heat Exchangers (GPHEs)

Brazed Plate Heat Exchangers (BPHEs)

Welded Plate Heat Exchangers (WPHEs)

Semi-Welded Plate Heat Exchangers (SWPHEs)

Each has unique characteristics suited for specific applications within food processing.

1. Gasketed Plate Heat Exchangers (GPHEs)

Design and Structure
Gasketed plate heat exchangers consist of a stack of corrugated plates held together in a frame. Each plate is sealed with elastomer gaskets that control the flow of fluids through alternate channels.

Key Features
Flexible and serviceable: Plates and gaskets can be replaced or added.

Corrugated plates create turbulence, enhancing heat transfer.

Gaskets allow easy disassembly and cleaning, which is crucial for food hygiene.

Applications
Pasteurization of milk, juice, and beer

Fermentation cooling

CIP (Clean-in-Place) systems

Hot water and chilled water circulation

Advantages
Excellent hygiene: Easy to clean and inspect.

Scalable: Plates can be added or removed to match demand.

High efficiency: Thin plates offer excellent heat transfer performance.

Limitations
Gasket limitations: Not suitable for very high pressures or temperatures.

Potential for leakage if gaskets degrade over time.

2. Brazed Plate Heat Exchangers (BPHEs)

Design and Structure
BPHEs consist of thin, stainless steel plates that are vacuum-brazed together using copper or nickel. The result is a compact, sealed unit without gaskets.

Key Features
No gaskets: fully sealed, making it more robust.

Extremely compact and space-saving.

Suitable for high-pressure and high-temperature applications.

Applications
Dairy cooling systems

Beverage carbonation cooling

Hot water heating

Refrigeration evaporators and condensers

Advantages
Compact design: Fits in tight spaces.

Durable: Resistant to high pressure and temperature.

Low maintenance: No gaskets to replace.

Limitations
Not serviceable: Cannot be disassembled or cleaned mechanically.

Less hygienic for some food-grade applications due to cleaning limitations.

Copper contamination risk in sensitive products unless nickel brazing is used.

3. Welded Plate Heat Exchangers (WPHEs)

Design and Structure
WPHEs feature plates that are fully welded together, often with no gaskets at all. They are designed for aggressive media and extreme temperatures and pressures.

Key Features
Fully welded for zero leakage in hazardous or corrosive processes.

Available in compact block designs.

Often used in combination with shell-type enclosures.

Applications
Processing of viscous or aggressive fluids (e.g., tomato paste, syrup)

Heat recovery in sterilization processes

Oil and fat processing

Steam heating of cleaning solutions

Advantages
Robust construction: Suitable for harsh environments.

Leak-free operation.

Long service life with aggressive fluids.

Limitations
Not cleanable by hand: Must rely on CIP systems.

More expensive than gasketed units.

No modification possible once fabricated.

4. Semi-Welded Plate Heat Exchangers (SWPHEs)

Design and Structure
These are a hybrid between gasketed and welded PHEs. Two plates are welded together to form a “cassette,” and the cassettes are gasketed between each other. One side has a welded channel, and the other has a gasketed channel.

Key Features
Allows handling of aggressive fluids on the welded side and cleanable media on the gasketed side.

Ideal for ammonia systems and corrosive fluids.

Allows partial disassembly for cleaning.

Applications
Ammonia condensers and evaporators

Fruit juice and concentrate processing

Sugar syrup heating

Vapor condensation in evaporators

Advantages

Dual functionality: Balances serviceability and durability.

Cost-effective for systems needing limited gasket exposure.

Suitable for partial CIP and mechanical cleaning.

Limitations

Still vulnerable to gasket failure on one side.

More complex construction raises cost.