Step 3 of 3•3 minutes read
Dedicated Direct Line Systems
A standard direct line system is the usual setup for traditional liquid cargo systems. This uses a single common cargo bottom line, and deck line for each grade of cargo carried. This limits the number of grades that can be loaded based on the number of lines and pumps available. It is overcome by a form of the dedicated direct line system that can theoretically carry as many grades as there are tanks.
A dedicated direct line system has one manifold, line, and pump per grade of cargo. Using the FRAMO system is possible as each tank can be segregated from the others, and the lines need never be common. This may be the most desirable system for certain chemical carriers as cargoes can remain fully segregated without blanks or double-blind connections to ensure separation.
For the FRAMO system, it is recommended to have separated filling and discharging lines within the dedicated direct line system. This branch allows bypassing the pump during loading so that greater pumping rates may be achieved without risk of damage.
A set of common, dedicated direct cargo lines on crude and product carriers is usually fitted with FRAMO systems. These allow carrying a few separate grades of cargo while minimising the number of pipes required. These can be seen in the photo below, with the raised common lines running along the centre of the deck.
