WÄRTSILÄ 46F Series, Product Manual

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The fresh water cooling system is divided into a high temperature (HT) and a low temperature
(LT) circuit. The HT water circulates through cylinder jackets, cylinder heads and the 1st stage
of the charge air cooler. The HT water passes through the cylinder jackets before it enters the
HT-stage of the charge air cooler. The LT water cools the 2nd stage of the charge air cooler
and the lubricating oil. A two-stage charge air cooler enables more efficient heat recovery and
heating of cold combustion air.
The cooling water temperature after the cylinder heads is controlled in the HT circuit, while
the charge air temperature is maintained on a constant level with the arrangement of the LT
circuit. The LT water partially bypasses the charge air cooler depending on the operating
condition to maintain a constant air temperature after the cooler.
9.2.1 Engine driven circulating pumps
The LT and HT cooling water pumps are usually engine driven. In some installations it can
however be desirable to have separate LT pumps, and therefore engines are also available
without built-on LT/HT pump. Engine driven pumps are located at the free end of the engine.
Connections for stand-by pumps are available with engine driven pumps (option).
Pump curves for engine driven pumps are shown in the diagram. The nominal pressure and
capacity can be found in the chapter Technical data.
Fig 9-3 L46F engine driven HT- and LT-pumps
Fig 9-4 V46F engine driven HT- and LT-pump
DAAB605814 9-5
9. Cooling Water System Wärtsilä 46F Product Guide