EN
Gasketed Plate Heat Exchangers: Versatility and Serviceability
Gasketed PHEs are the most widely used type, whose plates are made of corrugated metal and sealed with elastic gaskets. Their main advantage is their simple serviceability; they can be easily opened for inspection, cleaning or when plate number need to be added or removed. This makes them great for applications with dirty media flow or need access to maintenance as in central cooling systems. But gaskets restrict their operating temperature and pressure range, and can be the point of failure if they are made with the wrong material or if they deteriorate over time. Their usefulness depends largely on proper gasket selection for the media being sealed.
Brazed Plate Heat Exchangers: Compact and Leak-Tight
Brazed plate heat exchangers (PHEs) are formed by brazing together stainless steel plates with copper or nickel filler material. This results in a streamlined, durable and forever sealed piece without gaskets. They are able to withstand high vibration and are suitable for higher design pressure/temperature than gasketed units. Small size is great for applications such as refrigeration or hydraulic oil cooling and domestic water heaters. The main disadvantage is that they are inaccessible for mechanical cleaning or repair, and if the unit develops a leak inside it must usually be replaced.
Welded Plate Heat Exchangers: Robustness for Demanding Duties
Welded PHEs are a more robust alternative. In a fully welded version, the plates are laser-welded together to form a cassette and all gaskets are avoided. This design makes them ideal for corrosive fluids, high temperature and pressure applications where O-ring, diaphragm or gasketed hardware would fail. They find application wherever the going gets tough; for example in exhaust-gas cleaning systems or when processing aggressive chemicals. Though more durable, they still suffer from the same limitation as a brazed version: they are non-repairable in the traditional sense and will require machine shop facilities to properly repair one.
As a service provider, knowledge like this directly impacts our repair and maintenance and spare parts supply services at Sealong Marine Engineering Group (SME Group). Our technical team are experienced in stripping, re-gasketing PHEs - a typical repair job. For brazed or welded units, our image becomes more of a diagnostic and supply element, but also with the associated retrofit work in making sure the right type is specified to answer the needs of operation and maintenance for this one off concept, thereby justifying long-term system safety.