Eddy Current Testing Explained
We’ve frequently emphasized the importance of cleaning your tubes after you shut down your cooling system in the fall in order to minimize corrosion.
To protect the long term life cycle of chiller tubes eddy current testing (ECT) is an accurate means of determining the condition of both condenser and evaporator tubes.
The industry standard for ECT on the chiller tubes are:
-Test condenser tubes every three years
-Test evaporator tubes every five years
Eddy Current Testing can also be used to evaluate boiler tubes. If you need information on companies performing ECT on boilers contact your Chemtex rep.
How Eddy Current Testing Works
Eddy current testing uses electromagnetic induction to identify defects in tubes. A technician inserts a probe into the tube and pushes it slowly through the entire length of the tube. The probe’s electromagnetic coils emit eddy currents. These emissions are monitored simultaneously by measuring the probe electrical impedance.
How it Works
Waves are generated as the impedance changes.
Sensitive equipment detects these waves that identify flaws in the metal.
The testing equipment evaluates the waves and identifies problems with the condition of the tubes.
Pits, erosions, wears spots, and flaws in the tubes can be detected, both on the inside and outside of the tubes.
For more details on ECT, read our previous article on Eddy Current Testing.
ECT can detect imbalances on the tubes, pits, wear or erosion.
As you are well aware, tube failure can cause chiller shutdown, which can be disastrous. Detecting flaws on any tube can avert such failure and the accompanying shutdown.
Keep in mind that once you identify a tube prone to failure, you can isolate that tube. It’s not necessary to replace the tube bundle when just a few tubes exhibit problems.
Plan for Routine Eddy Current Testing
Include ECT in your budget and plans according to the recommended schedule. Preventing unnecessary shutdown from tube failures is worth the time and effort.
As always, your Chemtex rep will be happy to help you get your ECT routine set up for success. We always welcome your calls at Chemtex – it’s our pleasure to help make your job easier.