Abstract
The heat exchangers in the ships have been changed from the conventional shell & tube type to the plate type due to some merits as a compactness, a high thermal efficiency and a light-weight. In recent. it is reported that the vacuum phenomena were occurred in the seawater outlet piping of a main central cooler (MCC) on the ships. From the viewpoints of a common sense, the vacuum pressure in the seawater piping is rare event and difficult to be convinced because the seawater is pumped into the piping by a seawater pump with a high discharge head. However, the occurrence of a vacuum pressure in the seawater line of an MCC is real situation and often gives a severe damage to a rubber gasket of an MCC with a plate type heat transfer area. In this study, we analyzed the vacuum pressure in the seawater line of an MCC by using the simpl Bernoulli's equation and found that the vacuum pressure in the seawater line of an MCC is inevitable untill the installation postion of an MCC is not lowered.
