Oil becomes black

(1) Alagappan Coating inside the bearing... October 8th, 2007, 05:30 PM

(2) pumps100 Sorry but I don't think any... October 31st, 2007, 01:12 PM

(3) S. L. Abhyankar Dear Mr. Alagappan, To my... November 6th, 2007, 06:57 AM

(4) Alagappan Dear Mr.Abhyankar/... November 6th, 2007, 06:20 PM

(1) Dear all,

Please suggest based on your experience relevant coating to be used inside the bearing housing(oil sump) in order to prevent oil get balckened(change of colour) during operation. The material of the bearing housing is cast steel and oil used in the sump is ISO VG 46. The temp. may go upto 150 degree celcius.

Thanks in advance for the suggestions.

(2) Sorry but I don't think any coating system of your bearing housing is appropriate regarding your perceived 'problem' with the oil going black.

You don't say if you are having a problem with the bearings. Most lubricating oil will discolour after being put to work.

If you change the oil just because of its appearance (being black or discoloured) this is a mistake. What I would suggest is that you invest in getting the oil analysed next time you change it. This will tell you the condition of the oil and also give you an idea of what service intervals you really need.

However, if you do find that the bearing life is being affected by degradation of the oil quality, due to particulants/sediment build-up, and/or high temperature, you need to talk to the bearing and lubricant supplier to offer you a solution. This might involve a change in the oil type used, filtration, cooling, or simply a different maintainance regime.

Regards

John

(3) Dear Mr. Alagappan,

To my mind, surface of the oil reservoir has nothing to do with oil becoming black. Oil becomes black, due to wear of the bearings and due to carbonization of components of oil, especially when working at high temperature. In fact instead of worrying about oil becoming black, it should be used as the indicator to judge when to change the oil.

Regards,
S. L. Abhyankar

(4) Dear Mr.Abhyankar/ Mr.John,

Thanks for your valid suggestions.

Alagappan.E