Pump DE bearing temperature., 1

[M. ENG 18]

Greetings everyone,

I have an overhung pump driven by motor(45kw).
This pump is new installation in our plant.

During the 4 hours mechanical run test ( first run ) by water at ambient temperature. The DE ( outboard) bearing recorded temperature between 76 to 79 C and NDE bearing recorded 71 C. All vibration readings with the acceptable limits.

The bearing house is equipped by cooling water supply and during the test this CWS was lined up.

As per the vendor manual highest temperature is 82C, please find the following quote:
“(Based on the specified operation condition and ambient temperature 43C for ring oiler, oil sump temperature below 82 is expected.

The question?
Is this temperature consider high and not accepted especially it is very close to the maximum value recommended by vendor. Also, I wonder how the bearing temperature will be after the plant start up, because the original pumped liquid is water with normal temperature at 195 C.

Your valuable technical feedback is highly appreciated.

 

[Mech5656]

The bearing temperature is still below OEM recommended limits so it is fine. Just make sure to pay attention and see if this temperature goes higher in future. The bearing clearances may be a little tighter on drive end side since non-drive end bearing temperature is fine.

Are you using the process fluid in bearing housing coolers? If not, they should be separate fluids. 1) the pump is pumping and second is used to cool bearing housing using external source. What is cooling agent temperature at bearing housing coolers?

 

[gerhardl]

Question: 'because the original pumped liquid is water with normal temperature at 195 C.' ???

Comment: as MECH5656 states the temperatur is below required and not in general to regard as high if other conditions can allow it over time, and the contraption is constructed for it. At a running time of 4 hours a stable temperature balance between surrounding, produced, incoming and outgoing heat should have been reached.

Your question is obviously if there is any fear of increasing temperature. The answer is yes only if there is a relatively high increase in heat input. (See question. Printing error?)

 

[LittleInch]

Also I think you are reading into the manufacturers description something which isn't there.

What the vendor is saying is that the anticipated oil temperature sump will be 82C.

That's a long way from saying the MAXIMUM allowed temperature is 82C. I would suspect the max temp is quite a lot higher. Also oil sump temperature is different to the bearing temperature? What was the sump temperature?

I can only assume that the cooling water supply is sufficient to remove the heat coming along the shaft or within the housing in some way.

HOw far is the DE bearing from the pump?

As well as vibration have you checked that the alignment after your run period is still within allowable limits? This can often change during the shakedown run so needs checking and adjusting again.

And water at 195C will be interesting. I hope your seals are good.

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

 

[M. ENG 18]

Thanks A lot for all. Really your feedback helped me.

About the pumped fluid ( water) with high temperature 195 c, because it is burner cooling water.

About the question of the bearing cooling water, it is from external source.

About the question of the distance between the pump and the bearing housing, the pump casing very close from the bearing house.

 

[georgeverghese]

One can expect problems in the future with biofouling from CWS at this DE bearing housing.

 

[Maheshpowerplant]

For newly installed pumps, rise of bearing temperatures for a day or two days is normal,but it should nor cross temperature above 85 degree.If it is persisiting continuosly check the following installation related issues

Check alignment
Ensure pump is operating within rated load
Check vibrations..
Start stop frequency
Discharge line size
No.of immediate bends used in discharge line

If every thing is okay, then may go fore higher rating bearings.
May refer the this particles on bearings troubleshootng

https://www.powerplantandcalculations.com/2020/06/50-questions-answers-on-bearings.html