Cleaning a heat exchanger, also known as clean, test, and re-gasketing, is a process used to improve the heat exchange efficiency and extend the life of plate heat exchangers. While the process can be done in-house or by the manufacturer, often times it’s more cost effective to outsource the work to a heat exchanger repair center in your area.
Here is how to clean a heat exchanger for sanitary purposes including food, beverage, & dairy processing.
1. Remove gaskets and spray down the plates
Starting with a high-pressure wash and then finish the wash with a hand scrub to remove any product build up. This is an integral step in the process that directly relates to the increased efficiency of the heat exchanger after it’s done being cleaned.
2. Soak Plates
Soak the plates in a non-abrasive chemical solution to completely remove any leftover build up. The chemical solution type will vary based on the actual product build up you are removing but there are a variety of different mixtures you can create from non-abrasive acids such as acrostic acid.
Step 3: Dye-Test Plates for Defects
A custom dye spray gun can be applied using a fluorescent dye. After the plates are fully sprayed and dried they can be placed in a dark room and examined under a black light for any defects such as cracks, breaks, holes, etc. Finding these defects during the testing process will eliminate any cross contamination issues in future.
Step 4: Prepare the gasket grooves.
Look for a rolled gasket groove throughout the evaluation process which will allow you to prevent re-gasketing. If you don’t find the rolled gasket groove you should replace the plate to avoid unexpected down times.
Step 5: Re-gasket the plates
Start the re-gasketing process using only OEM manufacturer approved parts. Apply the gaskets back to the plates using an adhesive solution/industrial style glue. You can refer to the manufacturers guide to determine what type of adhesive you should use for your plates. Compress the gasket into the plate groove using the specific measurements for your plates.
Step 6: Heat Curing
Cure the plates in an industrial oven under the specific pressure recommended by the manufacturer. Heat cured gaskets last up to 10 times longer than standard clip on gaskets when the unit has to be opened repeatedly during a run cycle.
Step 7: Inspect for Defects
Inspect your plates for straightness of gaskets, strong bonding, surplus adhesives, and any general defects.
This article is provided courtesy of Harvill Industries, a process design, systems integration, sanitary equipment, and OEM service center for the food, beverage, dairy, cosmetics, biotech, and pharmaceutical industries.