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Eliminate cooling water of bearing by switch off lubricating oil type

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johngladstone

Mechanical
Dec 24, 2012
133
Dears
I get multistage pump used cooling water to coll bearing oil.
My plan is to eliminate cooling water and switch lubricating oil into higher grade.
My question if I change lubricating oil from iso 32 into iso 100 synthetic, is there any problem?
Appreciate for input
 
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It is impossible for us to give you a good answer with the information provided. What type of bearing? What size of pump? What operating speed? How hot does the oil run with cooling water on? How hot does the oil get with cooling water off? What is the range of ambient conditions? Is the pump inside or outside? Have you contacted the pump manufacturer? Is there guidance provided in the pump manual?

Johnny Pellin
 
Operating speed 1500, cylindrical roller bearing
Ambient temperature @range between 18-28 120 kw electrical motor
 
it depends on the temperature of the oil and the amount of cooling. how hot is the oil in the bearing and how hot is it when cooled down? theoretically it might be possible to use a thicker oil that attains about the same viscosity in service that you have now with cooling. be aware though that the designer of the pump has chosen a cooling system not because he likes it but because he thought it necessary for the pump to operate reliably.
 
You have not mentioned what problem you are trying to solve.

Regardless, making such a substantial change in turn makes YOU the person responsible for the bearings' future success or failure. ... even if they fail from unrelated causes.

... and it will certainly void whatever warranty now applies to the remainder of the equipment.

The proposed sort of changes are normally done, if at all, with the full cooperation and knowledge of the equipment manufacturer, and with a crapload of instrumentation recording all aspects of equipment performance before, during, and after the modification. Do you have the budget for any of that?







Mike Halloran
Pembroke Pines, FL, USA
 
@mike,
Actually I looking to improve the reliability of equipment by eliminating cooling water issue and switch off into synthetic lubricating
My question is it possible? Is there any case study occur before?
 
WHAT 'cooling water issue'? What problems do you associate with the presence of cooling water?

Have you spoken to the equipment manufacturer about the issue?



Mike Halloran
Pembroke Pines, FL, USA
 
Even if the synthetic oil has a better temperature index (viscosity stays at higer temperature) there is the surprising fact that the break-down voltage falls off much faster in synthetic oils than in mineral oils. So, if there is any voltage across the bearing, you may get EDM in the bearing. Shell cannot explain why, nor can Nynas. But the effect is there. We have checked in test rigs at the Nynas lab.

There is no good explanation, yet. So we just called it the Spaghetti Effect.


Gunnar Englund
--------------------------------------
Half full - Half empty? I don't mind. It's what in it that counts.
 
We have removed cooling water from hundreds of pumps with few, if any problems. But you have not provided enough information to say that you won't have problems with your pump. It can be done. In many cases the bearing will run cooler and last longer. But, this is not universally true.

Johnny Pellin
 
@jjpelin
You give me start hope to do this issue..
I looking to save operating cost by eliminating cooling water subject.. Please is there possible to provide us more information when you remove cooling water what kind of lubricating oil you use?
John gladstone
 
I am referring to ball bearing pumps with cast-in cooling jackets surroundind the bearing. 40 years ago, Heinz Bloch proved that removing the cooling water in this type of arrangement will reduce bearing temperature and extend life. We are located in Minnesota where temperatures can drop close to -40 F. We use ISO 46 mineral oil. With higher ambient temperatures, you may need to consider ISO 68 synthetic.

Johnny Pellin
 
Fifteen or twenty years ago, water cooled dyno motors, around 800 kW, had bearing problems because the bearings were running a lot cooler than the motor shaft. That ate tolerances and squeezed inner ring and balls against outer ring. The result was reduced oil film thickness and destroyed bearings. Remedy: water to bearing plugged. Solved the problem in this special case.

Gunnar Englund
--------------------------------------
Half full - Half empty? I don't mind. It's what in it that counts.
 
@jonny

Exactly i refer to heinz bloch suggestion for remove cooling water he gave example for ball bearing upgarde from iso 32 into 100.

Based on this can we use for anotger type if antifriction bearing?
What is exxonmobil name for iso 68 synthitic product.
 
Our preferred ISO 68 synthetic is Mobil SHC 626.

Johnny Pellin
 
@jonny,
Thank you, if i get choice between iso synthetic 68 and iso synthetic 100 what you advice me?
Is iso 68 you use it before and prove its quality for cooling?
 
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