Other Types of Heat Exchangers

Wide-Gap Plate Heat Exchangers

Advantages of Wide-Gap (Free Flow) Exchangers

1. Suitable for contaminated and viscous media – Thanks to wider gaps between plates, these units handle media containing solid particles, fibers, sludge, or high viscosity (e.g., fruit juices, waste, sugar solutions).
2. Minimal risk of clogging or fouling – Design without contact points between plates ensures freer media flow, significantly reducing clogging susceptibility.
3. Low pressure losses – Free flow allows better throughput even at low pressures – ideal for applications with limited pressure drop.
4. High thermal efficiency even with uneven flow – Even when processing non-homogeneous media, the exchanger maintains effective heat transfer.
5. Easy cleaning and maintenance – Removable design enables simple mechanical plate cleaning – no special tools or chemicals needed.
6. Application flexibility – Suitable for food processing, wastewater treatment, pharmaceutical industry, chemical processing, sugar production, and other sectors with dirty or demanding media.
7. Ability to handle media prone to crusting or deposit formation – Ideal where standard plate exchangers fail due to fouling.

Fully Welded Plate Heat Exchangers

Here is an overview of the key advantages of fully welded plate heat exchangers, designed for extreme conditions where conventional gasketed units fail:

1. Resistance to high temperatures and pressures – The fully welded design without gaskets handles extreme operating conditions – typically operating at temperatures above 300 °C and pressures over 25 bar.
2. Suitable for aggressive or hazardous media – The construction ensures safe operation with corrosive chemicals, flammable substances, or otherwise demanding media (e.g., ammonia, freons, hydrocarbons, organic solvents).
3. No gaskets = minimal risk of leakage – No sealing elements means no degradation, leakage, or contamination – ideal for critical operations with high safety demands.
4. Compact design with high heat transfer efficiency – Slim profile and profiled plates enable very efficient heat transfer even in compact units.
5. Low maintenance and long service life – No gasket replacements or complex disassembly – long lifespan even in harsh environments.
6. ATEX-compatible for explosive atmospheres – Robust, sealed construction makes it suitable for explosion-risk zones.
7. Flexible construction (modules, cassette variants) – Available in various forms – fully welded plate packs or semi-welded combinations (welded side for critical media, gasketed side for easier service).

Fully welded plate heat exchangers are primarily used in chemical, petrochemical, pharmaceutical, and energy industries where safety, efficiency, and durability are key.

Semi-Welded Plate Heat Exchangers

The main advantages of semi-welded plate heat exchangers are:

1. Safe operation with ammonia (NH₃) – The semi-welded design minimizes risks associated with ammonia leaks, which is both toxic and aggressive. The ammonia side is fully welded into cassettes, reducing the risk of leakage.
2. Combination of welded and gasketed exchanger benefits – The aggressive medium (e.g., ammonia) flows through welded cassettes, while the second medium (e.g., water or brine) flows between gasketed plates – allowing easy access and serviceability.
3. High heat transfer efficiency – Just like standard plate heat exchangers, semi-welded units maintain intense turbulence, resulting in excellent heat exchange – much more efficient than shell-and-tube designs.
4. Easy maintenance on the gasketed side – The side with gaskets (e.g., the water or brine circuit) remains fully accessible for cleaning, inspection, and service.
5. Space-saving design – The compact construction requires less space than comparable shell-and-tube units, which is advantageous in technical rooms or cooling plants.
6. Resistant to pressures and temperatures common in refrigeration systems – Designed to withstand higher operating pressures and temperature differences – ideal for industrial chillers, evaporators, condensers, or superheaters.
7. Lower ammonia charge – Compared to shell-and-tube exchangers, semi-welded plate exchangers require less refrigerant, increasing both safety and operating economy.

Spiral Heat Exchanger

Advantages of spiral heat exchangers:

1. Excellent self-cleaning capability – The single-channel flow path ensures turbulent flow, reducing fouling. This is a major advantage over plate or shell-and-tube exchangers in contaminated applications.
2. Compact and space-saving design – The spiral configuration offers a large heat transfer surface within a small footprint – ideal for confined spaces.
3. Outstanding thermal efficiency – The design supports counter-current flow, ensuring high heat transfer coefficients and effective temperature utilization.
4. Low pressure drop even with dirty media – The smooth and direct flow path prevents pressure spikes caused by directional changes, common in multi-channel plate or tube exchangers.
5. Resistance to fouling – Ideal for fibrous, viscous, or abrasive media, sludge, wastewater, or fluids with solid contaminants.
6. Easy maintenance – The design usually allows access to the channels via removable covers, simplifying mechanical cleaning.
7. Suitable for asymmetric flows – The spiral layout enables efficient heat exchange even with significantly different flow rates on the primary and secondary sides.

Typical Applications:

• Wastewater and process water in chemical, paper, or food industries
• Industrial alcohol production
• Cooling and heating of contaminated media
• Heat recovery from sludge and process fluids
• Biogas plants and wastewater treatment facilities

Plate and Shell Heat Exchangers

The Plate & Shell heat exchanger (a combination of a plate and a shell-and-tube exchanger) is a modern type of equipment that combines the advantages of both designs – plate and tubular.

Advantages of Plate & Shell Heat Exchangers

1. Compact design with high efficiency - Thanks to the plate pack (a welded set of plates) inside the pressure shell, it provides a high heat transfer coefficient with a very small footprint.
2. High pressure and temperature resistance - The gasket-free construction with a fully welded plate block allows operation at pressures up to 100 bar and temperatures over 400 °C, making it ideal for energy, petrochemical, or steam applications.
3. Combination of the advantages of tubular and plate exchangers - The exchanger combines the compactness and efficiency of a plate heat exchanger with the mechanical robustness of a tubular design – suitable even for hazardous or aggressive media.
4. Low pressure drops and asymmetric flow capability - Thanks to the configuration of the plate pack, it is possible to optimize flow channels even for significantly different volumetric flows on the primary and secondary sides.
5. Easy installation and minimal space requirements - Compared to a classic shell-and-tube exchanger, it offers significantly smaller dimensions and weight at the same performance.
6. High reliability and minimal maintenance - The welded construction without gaskets is resistant to leaks, gasket degradation, or wear – ideal for long-term operation without frequent maintenance.
7. Possibility of operation with hazardous substances - The sealed construction is safe for gases, steam, aggressive chemicals, or flammable substances, which is crucial in refineries, power generation, or cooling systems.