Heat Exchanger

Double-pipe heat exchangers
Double-pipe heat exchangers, also known as a hairpin or jacketed pipe exchangers, are the simplest type of heat transfer equipment. They are made of two concentric pipes with different diameters. The process fluid flows through the smaller inner pipe, and the utility fluid flows through the annular space between the two pipes. The wall of the inner pipe acts as the conductive barrier between the two fluids wherein heat is transmitted. The countercurrent flow pattern is the most utilized, though it may be configured to co-current flow.

Shell and tube heat exchangers
Shell and tube heat exchangers are composed of tubes arranged in a bundle that is housed in a large cylindrical vessel called a shell. Similar to the double pipe heat exchanger, the wall of the inner pipe acts as the conductive barrier. The process fluid flows in the tube side, and the utility fluid flows on the shell side.

Gasketed plate heat exchangers
These types use gaskets to connect and seal the plates together. They are widely used in industries that require frequent sanitation, like food and beverage processing. Gasketed plates reduce maintenance costs since they are easy to clean, dismantle, and assemble. More plates may be added to increase the heat exchanger‘s capability and throughput. The disadvantage of this type is its potential for leakage.

Welded plate heat exchangers
Welded plate heat exchangers reduce the possibility of leakage. They are also similar to a gasketed plate heat exchanger, except that the plates are welded. They can handle higher temperatures, higher pressures, and more corrosive fluids since the operating temperature is not limited by the gasket seals. They are also more durable than gasketed plate heat exchangers. Since the plates are permanently fixed, manual cleaning is not possible.

Brazed plate heat exchangers
These heat exchangers have plates joined by a process called brazing, where two pieces of metal are joined by a molten filter metal. Brazing creates a low thermal resistant joint and is the reason brazed plate heat exchangers are so efficient. They are used in chillers, pumps, evaporators, and condensers. Brazed plate heat exchangers are efficient, compact (consume smaller floor space), and have long service life even under continuous exposure to high pressures.

Plate fin heat exchangers
These types consist of alternating layers of corrugated metal fins and flat metal plates called parting sheets. The fluid streams pass through the interface created by the fin and parting sheets. The parting sheets are the primary heat transfer surface. The fins create a secondary heat transfer surface, and they serve as the mechanical support of the plates against high internal pressures. The sidebars are also fixed to prevent the mixing of the two fluid streams. All components are bonded by brazing. Countercurrent flow configuration is incorporated in most designs.

Plate and shell heat exchangers
Plate and shell heat exchangers combine the best features of a shell and tube heat exchanger with a plate heat exchanger. A fully welded plate is placed into the shell to distribute stress and eliminate the need for gaskets. The a fluid passes through the plate side flow channel while the b fluid passes through the shell flow channel. The result of the design is a high heat transfer rate.

Chemical cleaning
Chemical solutions are commonly used for heat exchanger cleaning and have proven effective in removing a wide range of deposit types. However, chemical cleaning has certain drawbacks, including the need for proper disposal of chemicals, potential environmental hazards, and the requirement for additional mechanical cleaning to ensure optimal results. The merrick group experts will review if chemical cleaning services are right for you.

Mechanical cleaning
Mechanical cleaning involves using tools that are selected based on the type of deposit to be removed. Molded plastic cleaners are effective for light silt, while brushes can be used for both microbial deposits and silt. Brushes can be adapted to clean tubes with various surface enhancements, such as fins, spirals, metal inserts, or epoxy coatings. Metal cleaners are designed for harder deposits and come in different designs to match the deposit and tube diameter. If you’re not sure which industrial cleaning service your equipment needs, trust the experienced team at the merrick group to make a recommendation.

High-pressure water cleaning
High-pressure water cleaning has become increasingly popular for heat exchanger cleaning due to its effectiveness. It can efficiently remove mineral deposits, scale, biological matter, and other debris. High-pressure water systems also facilitate easy collection of the removed deposits, allowing for better tracking of buildup levels over time and establishing a more regulated inspection and cleaning cycle.
Other cleaning systems and processes, such as combination air and water systems or compressed air systems, may also be available, each with their own specific practices and effectiveness depending on the tube and deposit characteristics. Regardless of the method used, it is crucial to rely on a highly trained heat exchanger cleaning service crew.