February 22, 2019
Heat exchangers are exposed to stress. Every day, all day long, the heat trading devices are hit from two different directions by two different fluid mediums. Then, because of the mechanical and thermal stresses, a crack develops, the vessel leaks, and the entire system experiences a performance tumble. Thankfully, by knowing why a heat exchanger undergoes such performance hits, we gain a service-vital edge.
When Heat Exchangers Hit The Skids
It's a colourful term, but it illustrates a very real problem. Remember, heat exchangers function at the heart of uncommonly active thermal systems. A hot fluid flows, then it enters a tube stack or plate array. When the equipment, the pressure vessels and fittings operate properly, energy is swiftly traded. However, a disabled device will rapidly sap both systems, even if those fluid networks are normally isolated from one another. A leak springs, weld seams corrode and the vessel paintwork peels. An unappealing orange bloom spreads, and production rates drop. Worse yet, if the fluids are chemical or food-based, the corrosion could jump a pipe-segregated boundary and spread the pollution.
Hunting Down Common Heat Exchanger Malfunctions
Bad enough, two watery fluids mix because of a leak, but what if one fluid is steam-pressurized while the other is a liquid? What if caustic chemicals pool below a pressure vessel? That's a situation that cannot be allowed to take place. To stop heat exchanger faults from developing, system managers initiate scheduled planned maintenance strategies. And, supporting that strategy, a list of common causes of heat exchanger faults is compiled. Exchanger leakage ranks high on the list. But remember, there are two fluids in the vessel. Is the leak taking place in the tube stack? If not, can it be traced back to a tiny material discontinuity on the shell? Then there are vibrational problems to address, fouling migration, which also causes performance drops, and air pocket formations. That latter issue occurs when seal damage and/or venting problems suck air into the vessel.
The goal here is to gain an advantage, which can then be used to identify and address a heat exchanger problem before it affects system performance. Case in point, why is the vessel leaking? Is there a fabrication fault or material flaw that wasn't picked up back at the factory? More likely, a force is in play in and around the equipment. Vibrational problems are a good example of such system-damaging energies. The vibrations must be held in check. If that solution doesn't yield positive results, the noise propagating channels can be eliminated, perhaps by replacing a rigid pipe with a flexible hose.
Fusion - Weld Engineering Pty Ltd
ABN 98 068 987619
1865 Frankston Flinders Road,
Hastings, VIC 3915
Ph: (03) 5909 8218
Optimized by NetwizardSEO.com.au