Case Study – Using AUTOGLO® AL-4B to inspect heat exchanger plates


August 2016



Our customer is an independent UK-based company that carries out inspection of heat exchanger plates. Approximately 60% of their business comes from the inspection of heat exchanger plates used within the food and drink processing industry. They also carry out inspections on plates coming from cruise ships and ferries. Typically, inspection of plates will be carried out on an annual basis.



The heat exchanger plates are inspected for cracks and holes that penetrate the plates; this is essentially a leak test and is carried out using fluorescent penetrant. The penetrant is applied to one side of the plates using an air spray system and left on the surface for 6-8 hours before being inspected using a UV light.

Our customer was using an oil-based penetrant to carry out their inspections. A water-based penetrant would be better practise, given that they carry out a high proportion of work for the food and drink processing industry. Oil-based penetrants are primarily used within other industry sectors; water-based penetrants are, in general, chemically safer, easier to remove and often biodegradable.



Magnaflux EMEAR had two potential solutions for this customer:

  • MAGNAFLUX® FP-10 is a special high-sensitivity, water-washable UV fluorescent penetrant developed for the food and drink processing industry. It carries NSF registration.
  • AUTOGLO® AL-4B is a low-sensitivity, water-washable UV fluorescent penetrant which is both water-based and readily biodegradable. Using AL-4B, the penetration time would be very short, typically 2-15 minutes when used as a conventional penetrant, and 15-30 minutes for the purpose of carrying out a leak test.



We sent samples of both products to our customer to trial. They obtained the following results:

  • With the MAGNAFLUX® FP-10, the higher viscosity of the product meant that they had to open up the spray gun more. This resulted in a risk of getting drops of the penetrant on the reverse side of the plates, which would lead to a false test result.
  • With the AUTOGLO® AL-4B the results were perfect. The product was easy to use and gave clear indications under UV light quickly.


“Using Autoglo AL-4B, we obtained perfect results for our leak tests. What is great about AL-4B is that it is easy and quick to use. Coupled with this, we are safe in the knowledge that it is a biodegradable water-based penetrant.”

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