MARINE FOCUS
Air con system cleaned ‘in
transit’ on board a dive support vessel
W
elch Refrigeration has worked in the marine refrigeration and air conditioning industry for many years and travelled the world with its reputation to repair existing systems whilst in transit, or when required while the vessels are in dock. One such ship, a dive support vessel, was heading for the tropics and then on to Australia. It had been working for some 25 years in the North Sea and was fitted with a Stal-Levin packaged water chiller.
While working in the North Sea, there was never a need to run all three air conditioning systems on board – so they had run only two. The heat transfer fluid in the system had leaked into an unused refrigeration system and had been left for a number of years, so unsurprisingly, the internals of the system had corroded badly and there was evidence of encrusted material. The vessel would need this third system running before entering the warmer climate. In addition, once it was in Australian waters, it would be required by law to keep crew and workers at a consistent temperature. Gary Welch, owner of Welch Refrigeration, consulted with Climalife, his refrigerant supplier, to find out if there was anything that could clean the system internally, or if it was going to be a case of fitting new equipment. If the latter, their customer was concerned about the cost of new equipment. Mr Welch suggested two suitable Climalife products and his customer agreed to give them a go.
Mr Welch joined the ship when it docked at Peterhead and worked on the refrigeration system during its voyage to Singapore. The system pipework was isolated and Desoxydant P was used first. Having consulted the product data sheet before use and then diluting the product, Mr Welch was able to
dislodge a significant amount of sludge and encrusted material.
The system was then flushed with Dispersant D, which resulted in further amounts of solid type material being cleaned away from the unit. Generally, it is difficult to see what effect some of these cleaning chemicals can have, however Welch refrigeration used an internal camera that showed the amount of rust before and after on one particular pipe.
One particular part of the system that caused Welch Refrigeration a problem was the discharge stop valve, which had rusted solid. The valve was soaked in Desoxydant P for
approximately 24 hours which had the desired effect of freeing it. Once serviced, they were then able to re-instate the valve.
These products are generally used in heat transfer fluid systems, but the system to be cleaned was for a badly corroded refrigerant circuit.
After cleaning, the system was dried out completely and put onto a complete vacuum before re-introducing the refrigerant. The cleaned system returned to a fully functional state and was back in service, ready to provide the air conditioning required, before the ship entered tropical waters.
Sludge returning after flushing with Desoxydant P.
www.acr-news.com
August 2017 59
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