9. Cooling water system1579. Cooling water system9.1 Cooling water systemThe cooling water system is of the indirect seawater cooled, fresh water circulation type. The cylinders,cylinder heads and exhaust manifold are cooled with fresh water, and fresh water cooler (heatexchanger) use seawater.Seawater pumped in from the sea by the seawater pump goes to the heat exchanger, where it cools thefresh water. Then it is sent to the mixing elbow and is discharged from the ship with the exhaust gas.Fresh water is pumped by the fresh water to the cylinder jacket to cool the cylinders and the cylinderhead. The fresh water pump body also serves as a discharge passageway (line) at the cylinder headoutlet and is fitted with a thermostat.The thermostat is closed when the fresh water temperature is low, immediately after the engine isstarted and during low load operation, etc. Then the fresh water flows to the fresh water pump inlet, andis circulated inside the engine without passing through the heat exchanger.When the temperature of the fresh water rises, the thermostat opens, fresh water flows to the heatexchanger, and it is then cooled by the seawater in the tubes as it flows through the cooling pine. Thetemperature of it flows through the cooling pine. The temperature of the fresh water is thus kept within aconstant range by the thermostat.PPSeawater circuitFresh water circuitThermostatSeawater pumpSea cockFresh water pumpHeat exchangerCoolant recovery tankMixingelbowCylinder headCylinder block
