Lubricating oil system valves

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Pengze
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Joined: Tue Sep 23, 2008 8:57 pm

Lubricating oil system valves

Postby Pengze » Mon Sep 20, 2010 1:04 am

Recently, we were asked to change all globe valves to gate valves for the main engine's lubricating oil system .
As for the suction valve from sump tank, we were also told to use the non-return flap-type check valve. Presently, our system is using screwdown non-return globe stop valve.
Any comments & advice regarding these specific issues?
Appreciate yr feedback.
Have a nice day.
Thanks.

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JK
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Re: Lubricating oil system valves

Postby JK » Mon Sep 20, 2010 11:06 am

I will admit that I have never been asked to change valves to a different type in a existing system, but I am sure that will pop up to ruin my day.
I can only assume that the thought is the gate valve is fully open\closed and allows full flow through it while the globe valve is not designed for general shut off but for throttling and the implications of that in a LO system.
Out of curiosity. if you can answer, who wanted this changed? I will be doing some reading of rules or regulations.

Pengze
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Joined: Tue Sep 23, 2008 8:57 pm

Re: Lubricating oil system valves

Postby Pengze » Mon Sep 20, 2010 6:42 pm

Dear JK,
Thks for yr reply. You are spot on, that the gate valves are meant for full flow.
But then the common problems with gate valves are that the gate will drop, stuck, jam or partially open/close due to worn thread & poor material.
This system valves had been approved by Class but recently we had a major main engine re-building overhaul in progress & these valves are recommended to be change by the engine maker's specialist.
So, my contention is , if we still use the present globe valves, will that affect the integrity of the lubricating oil system?
If I am not mistaken, so far in my seafaring career, I always come across the globe valves in the lube system.
Any suggestions & kind advice will be appreciated.

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JK
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Re: Lubricating oil system valves

Postby JK » Tue Sep 21, 2010 1:34 am

it seems like a lot of money to replace something that is approved and is functioning.
The FSR is suggesting valves in their spares manual?

Pengze
Mechanic
Posts: 60
Joined: Tue Sep 23, 2008 8:57 pm

Re: Lubricating oil system valves

Postby Pengze » Wed Sep 22, 2010 7:44 pm

Dear JK,
You are right. It sure cost substantial to replace what is being used at present & approved by Class.
But then there is still no definitive answer to the usage of gate valves against the globe valves in the marine lub.oil system. What will be the consequences if we do not use the gate valves?
Appreciate any professional advice from our marine engineers out there.


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