What is Direct line cargo piping system on tankers?

Direct line system is the simplest type of pipeline system which uses fewer valves than the others. It takes oil directly from the tank to the pump and so reduces friction.

This has an affect of increasing the rate of discharge, at the same time improving the tank suction. It is cheaper to install and maintain than the ring main system because there is less pipeline length and with fewer valves less likelihood of malfunction.

However, the layout is not as versatile as a ring main system and problems in the event of faulty valves or leaking pipelines could prove more difficult to circumvent.The washing is more difficult since there is no circular system and the washings must be flushed into the tanks 

Direct line system

Advantage:
  • Quick loading & discharging.
  • Short pipe line.
  • Less bend.
  • Less loss of pressure due to pipe line friction.
  • Direct line to provide better suction.
  • Time of washing the line is short.
  • System is cheaper than the other system.
  • Leak is minimized.
  • Easy to operate so less training is required.
  • It is easy to separate each cargo.
Disadvantage:
  • In case of leaking the control of leakage is difficult.
  • This system is very inflexible.

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Fig : Direct line system

RAVI PRAKASH

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