Friday, June 14, 2013

L.O Cooler Leakage..How Detect and Testing!

MEO SUCCESS

L.O Cooler Leak Detection

cooler plate type
plate type l.o cooler
When we talk about L.O cooler, first thing comes to our mind that ok, the cooling medium is Water.
Now General arrangement of water type L.O cooler (generally plate type)
is that water enters the plates from one side and l.o from the other, such that they both cross each other which ensures maximum interaction (heat exchange).

Now suppose due to any factor, excessive sea water pressure or corrosion, the water side gets corroded, then water will start to release to the l.o.
This is a major danger!
Thus to combat this we have to keep a close track on the quality and contamination level of Lub Oil (l.o).

Broadly, there are two hazards in L.O contamination..
  • Sea Water Ingress in L.O (main topic)
  • Microbiological Development (big enemy)
Sea Water Ingress in the L.O can be detected in many ways,
  • Onboard Lub Oil Tests
  • Shore Based Lub Oil Tests
  • Purifier Sludge tank filling too fast (easiest indication)
Purifier Sludge Tank definitely fills up faster if there is an water ingress in l.o.
L.O Purifier separates out deposits and water content form the l.o system that is circulated from the L.O sump of engine.
Now if there will be water ingress then more water will be separated and the separated sludge goes to the L.O sludge tank.Thus its sudden increasing level implies L.O Cooler Leakage!

Reasons to test L.O

  • To monitor the deterioration of quality of oil with time
  • To  check for contamination with other oil, water and microbacterial attack
  • To avoid damage to the lubricating part of the machinery
  • To determine any leak or source of contamination of oil
Sampling Point For L.O

The sample to be tested (be it shore based or on board) must be ensured to take after the L.O system with system in running condition.
Some C/E ask to take samples before the system, but it is good practice to take post system.
Also allow sample to cool to atmospheric temperature before use.

Shore Based L.O Testing at Lab

The sample is filled in the bottles provided by the lab (Visva Lab most popular).
Then a form is filled for information about the oil and its running hours.
Put all the things in a courier packet.
Later fill a removal report and submit it to agent for landing at next port.
They will send a report in few weeks by email.

Onboard Lub Oil Tests

Certain tests are done to test water leakage.They are explained further,
  • Water Ingress Test
5 ml of sample is taken inside digital water content meter mixed with 15 ml of reagent containing paraffin or toluene. Before closing the lid of the digital meter, a sealed sachet containing calcium Hydride is kept and container closed tight. The meter is shaken by hand and the pressure rise due to the chemical reaction in the test container is shown as water percentage in the digital display.
  • Testing its Viscosity
This test is performed by using a Flow stick in which two paths are provided for flow of oil side by side. In one path fresh oil is filled and in other side path used sample oil is filled. Now the flow stick is tilted allowing oil on both paths flowing in the direction of the tilt due to gravity. A finish point is provided along with reference points along the flow stick and the position of used oil is checked when fresh oil reaches the finish point.
  • Spot Test
In this test a drop of lube oil is put on the blotter paper and it is then dried for few hours. The dry spot is then compared with the standard spot available which determines the insoluble components in lube oil.

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3 comments:

  1. normally it doesnt happen.. LO pressure is always higher, so lub oil will get leaked to sater sid. How can we detect this apart from daily sounding ? by the time we detect by sounding, tones of LO will go to sea.

    ReplyDelete
    Replies
    1. i would get you some stats of pressure in cooler soon!
      this allows us to think other wise..
      but it is remarkable to know that ideally soundings of tanks are done in every watch..so that way, it would be more quicker.
      Secondly you would notice, that if the lub oil leaks, its pressure would drop at the gauge and temp would rise noticeably, if the leak would be severe.this way you can detect!
      hope you get the idea :)
      and thank you for reading my post!

      Delete
  2. Can you add about Additives we add to Lube oil?

    ReplyDelete

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