Heat Exchanger Construction is a Complex, Interesting Process
Boaters know that every piece of equipment on their vessel is important. But, when it comes to heat exchangers and oil coolers, the help of a professional is needed to design and match the cooler to the vessel and its engine system.
But how is a heat exchanger built? The heat exchanger consists of a series of tubes all joined together to make a “bundle.” The bundle is inside the metal casing of a heat exchanger. There are inlets and outlets fitted to this metal casing. All joints and fittings are brazed together.
The operational part of a heat exchanger is the cooling tube. The cooling tubes are constructed of either copper or a copper nickel alloy known as cupronickel. The alloy is made with a 90/10 ratio, which offers increased resistance to salt water corrosion and befouling.
The casing is built by cutting a flat sheet of copper metal to a pattern. The holes that will later be where the hose fittings are attached are punched at this time. Manufacturers build a custom heat exchanger with computer design as well as paper patterns or from the original heat exchanger itself.
The next step is to deal with the bundles, which are all the tubes that go inside a heat changer. The bundles are brazed together at almost 1,000 degree temperatures to keep them together and in place. After the bundle is made, the outer casing fitted. The final step in the construction process is to add hose fittings or barbs, zinc fitting, a pressure tank (if required), and end-fittings.
The heat exchanger is pressure tested, given a final inspection and then painted to ensure a long service life. And there you have it – the heat exchanger is complete!