AIR BLAST COOLER SERVICE

We installed two 400 kW air blast coolers last year on a West Midlands site to provide cooling for a pair of giant ZR40 air compressors. The coolers have ran well for the last year with only minor down time to remove leaves and rubbish from the underside of the units. As we drew into the hot weather last month return temperatures coming from the Air Blast Cooler were running high so we advised the client a service and coil clean was required. We took one compressor and air blast cooler off line at a time and carried out a service. The cooler valves were shut allowing it to cool down, then the electrical supply isolated and locked off. First using a small pressure washer debris was removed from the coil underneath the unit. Tree pollen and other small debris coagulates at the lower side of the coils and restricts air flow up through the unit thus decreasing efficiency. Leaves normally fall off when the fans shut down, those that are stuck in the frame come out easily with the pressure washer. The fans are then unbolted and raised individually. Using the pressure washer the coils are soaked with water and then a coil cleaner is sprayed over the tops of the coil. We use a chemical designed specifically to clean (or brighten) heat exchanger coils. The chemical removes dirt, grease and any oxidant forming on the surface of the coils. It takes a several minutes to soak down and work so we repeat the process under all the fans then take a short break. Each chamber is then pressure washed from top down to remove the chemical and any dirt removed by the cleaner. The chemical is specially selected to cause no harm to the environment and is bio degradable so disposal causes no concerns. Although this brand takes longer to work, the additional levels of safety achievable for the users and environment make it a worthy choice. When the coils are all cleaned and washed the underside of the air blast cooler is cleaned so the underneath ground is clean and free from debris. All the fans are bolted back into place then checked for tightness. The fan blades are then pressure washed taking care to keep the high pressure water away from the motor casings. The entire outer case was then given a wash down. A thorough inspection of the electrical panel was carried out and connections checked for tightness. The cooler was put back on line and the fan motor currents measured and recorded. The other cooler was then taken off line causing this cooler to rapidly increase speed. The temperature was adjusted to cause the cooler to run at 100% demand and the motor currents measured again and recorded. The cooler was then set back to the original set point and put back into service state. A good visual inspection was carried out of the whole casing, coil, headers, covers and electrical isolators whilst the above works were carried out. The other air blast cooler was then cleaned and serviced in a similar method and both returned back into service. If you have an air blast cooler and it needs a service, clean or repair, why not contact us for help?

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