Condenser Tube Inspection




Basic

Condensers come in two main varieties, the first kind used in chemistry, which consists of glassware used for the cooling of hot vapours into liquids. These are the kind we’re not interested in, they don’t require any sort of non destructive inspection, instead we’re interested in the second kind. These are commercial condenser used for industrial applications, they often serve the purpose of heat exchanger and condenser in one rapid motion.

In a typical setting such as a strength stop, these condensers will be installed at the outlet of each steam turbine. As the steam passes by the turbine, it’ll flow into the condenser, and fill the shell area. The shell contains the hot vapour, but also allows cool water to flow by, via a series of tubes, organised into the most efficient configuration to maximise heat exchanger. As the steam comes into contact with the tubes, it condenses and flows off into the bottom of the condenser, often collecting in a pan known as a hotwell. The water in the tubes is simultaneously heated, and can go on to be used in other applications in the strength generation course of action.

The problem with the time of action however, is that impurities in the water and steam can build up on the surface of the heat exchanger tubes, reducing their effectiveness at transferring heat. This is a problem, as time goes on, the system becomes less and less effective, and in the case of strength stations, generates less and less electricity. For this reason it’s economically sensible to inspect the condenser tubes regularly to monitor the build up of fouling, and continue an permissible condition within with tubes.

Non destructive testing is the solution to this problem, and not only allows the build up of fouling to be checked, but helps provide vital information about the state of the heat exchanger. It allows a record of data to show that safety is being maintained, for compliance with regulations. It allows any problems to be remedied as they happen, and allows a log of inspections to be kept, so data can be analysed, and trends discovered.

Inspection can be carried out via several methods, two of the most shared and effective technologies are eddy current, and ultrasonic. Eddy current can be utilised for ultra high speed inspection, allowing up to 8 tubes per minute to be inspected, and a tube sheet map to be generated, visually displaying the condition of tubes in an easy to digest manner.

Because of the speed, inspections can be completed on 10,000 tubes in 2 days. This clearly is advantageous when shut down time is at a premium, and allows tubes to be replaced or repaired rapidly.




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