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Join Date: Oct 2007
Location: NIGERIA
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FATIGUE ON VERTICAL RAW MILL ROCKER ARM

12/23/2007 5:22 AM

At a short interval,a newly mounted rocker arm hook joint out of four rocker arms on vertical raw mill (VRM)of a cement plant was found broken,just of recent the head of the hydraulic jack piston was broken which was replaced with hydraulic jack.The rocker arm is actuated by hydraulic jack and its unit.what are the likelyhood causes of this problem.Thanks.......

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Guru
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#1

Re: FATIGUE ON VERTICAL RAW MILL ROCKER ARM

12/23/2007 6:33 AM

Can the hydraulic jack drive the arm too far such that it trying to exceed the available travel?

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#2

Re: FATIGUE ON VERTICAL RAW MILL ROCKER ARM

12/24/2007 12:09 AM

Sounds to me like it wasn't installed to withstand beyond full stroke?

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Commentator

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#3

Re: FATIGUE ON VERTICAL RAW MILL ROCKER ARM

12/24/2007 1:14 AM

Hi Olusola,

Problem appears due to over load or misalignment.

Overload may be due to joints getting jammed for some reason or inadequate lubrication.

Otherwise, it may be due to misalignment at the joint and the load may not be getting transmitted fully along the central axis of the jack's piston.

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Guru
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#4
In reply to #3

Re: FATIGUE ON VERTICAL RAW MILL ROCKER ARM

12/24/2007 12:16 PM

Problem appears due to over load or misalignment.

That's it!

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Guru

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#5

Re: FATIGUE ON VERTICAL RAW MILL ROCKER ARM

12/25/2007 9:47 AM

It could be useful to send a photo of the failed parts since the failure shows what were the reasons for the fatigue.

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Power-User

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#6
In reply to #5

Re: FATIGUE ON VERTICAL RAW MILL ROCKER ARM

12/25/2007 10:24 PM

I agree. Photos of all intregal parts will show where the loading is occurring and the type of stress. Possibly, the source of the fatigue will reveal itself.

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