Page 85: of Maritime Reporter Magazine (March 1997)

ea Water Intake, Cooling System Designed For Overall Cost Savings

Since JAK-System's introduction ) the maritime market two years go, there have been many mprovements. The seawater ntake and cooling system is touted >y its developer, Acomarin

Engineering, as saving both ship- yards and owners time and money.

This is due to the fact that the whole suction piping will be avoid- ed, providing for enormous sav- ings. Also, Acomarin points out that corrosion of the sensitive sea- water piping will be reduced, and the filtration degree and net filtra- tion area will be better.

The JAK-System allows all bal- last water to be taken in via one sea chest. The ballast water is treated with a combined transduc- er of ultraviolet light and ultrason- ics, which has reportedly been proven to be an excellent method of killing bacteria, while possibly destroying barnacles and other water microbes. Acomarin views this point especially vital, as the international maritime community now grapples with the problems of ballast water disposal around the world. Acomarin received a recom- mendation letter from The Finnish

Board of Navigation to use the

JAK-Sea Water Intake and Cooling

System in the new 10-MW multi- purpose icebreaker/offshore con- struction vessel.

The system design includes (see diagram below) six diesel generat- ing sets as the main electric power source, with each diesel equipped with individual central coolers.

The arrangement will allow indi- vidual cooling water controls and balance for each generating set.

Due to the frequency controlled cooling pumps — one running, one standby — it is possible to reduce the seawater cooling temperature and quantity used for the cooling of each engine, as the vessel will mostly operate in the Baltic and

North Sea. It is, however, impor- tant to keep coolers' physical char- acteristics in optimal working order. This means that it would be necessary to select a special plate heat exchanger having two split sections for sea water and the sec- ondary flow of fresh water flowing at all times through both sections.

The SW Flow Controls will be secured by means of the actual flow measuring transmitter and controller, which will be automati- cally set from the shipboard com- puter according to the load and valve position conditions.

The flow controller will automat- ically set the pump capacity via the frequency controller. Ice blocks

March, 1997 and brash are a big problem for vessels operating in heavy ice con- ditions. As front runners, ice- breakers must operate even better than conventional vessels. Both the filter mesh and the form of

JAK-Sea Chest act an important role in the ice and air evacuation.

Disturbances caused by air in cen- trifugal pumps increase as vessel speed increases. In certain condi- tions air-related problems are encountered in centrifugal pumps on all vessels. In order to remove air from the pipelines, various expansions are made in the pipings with venting pipes led to the fun- nel through automatic vent valves.

However, air still causes problems in the cooling system occasionally.

The JAK-system appears to eliminate air-related problems. As the sea chest is locat- ed in the mid-ship area, the water flow rate is extremely low and any air bubbles will rise straight up to the air space without passing through the close-meshed filter plate to the pumps. The rising velocity of the air bubbles is obvi- (Continued on page 97)

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