Potential Causes for cracks in Suction Liner in Slurry Pumps?

[billions]

Looking at very large slurry pumps with a high chrome white iron suction liner. We're seeing some very large cracks in the inside/hole/inlet of the suction liner.

Could be many things like, over or under torqued bolts, rapid heating (really cold here), dropped it, large nose gap (more turbulence).

What else could it be?

I'm trying to investigate, so any recommendations/insights would be cool.

 

[Artisi]

What are you pumping?

It is a capital mistake to theorise before one has data. Insensibly one begins to twist facts to suit theories, instead of theories to suit facts. (Sherlock Holmes - A Scandal in Bohemia.)

 

[billions]

Bitumen ore and water

 

[JJPellin]

Rapid heating. These cannot tolerate more than about 50 F per hour.

Johnny Pellin

 

[billions]

Change of 50f per hour? That's it?

I'm suspecting they've done from (-10 to -25) at that time, even colder now. Up to 85C pretty much quickly.

Do you have any links /docs that I can see on the 50F/hr? Would be awesome

 

[Artisi]

what is the material break-down for the pumped material, large hard solids / fine solids and percentages?
Hard metal pumps aren't necessarily the best selection.

CORRECTED TYPO, "PUMPS ARE" TO *PUMPS AREN'T*

It is a capital mistake to theorise before one has data. Insensibly one begins to twist facts to suit theories, instead of theories to suit facts. (Sherlock Holmes - A Scandal in Bohemia.)

 

[JJPellin]

Look in the manual for your pump. There will be a warning for maximum heat up rate and it will include a maximum rate of change.

Johnny Pellin

 

[billions]

@artisi idk where my reply went. Its bitumen ore , slurry, high d50 of 350, high fines. They've tried a PU liner and didn't work. It's a high impact zone.

I agree. Based on the data and discussions with maintenance/reliability I've narrowed it down to Low temp during install (lower than MDMT) which caused it to become extra brittle. Then torquing it ctrated micro fractures/cracks which were rapidly accelerated by flushing with hot process water.

This is what our best thought is so far.


@Jp I was looking for manual today but damn these things are hard to find. Also this liner wasn't the original I believe.

I do believe that the quick temp change was one of the issues. Some of the problems maintenance hasn't accounted for working in northern Canada

 

[Artisi]

When you say, "not the original" - do you mean a pirated part or is it genuine?
If an ongoing problem, I wouldn't dismiss a "rubber" liner, depending on the manufacturer, some have a wide range of material to select from.


It is a capital mistake to theorise before one has data. Insensibly one begins to twist facts to suit theories, instead of theories to suit facts. (Sherlock Holmes - A Scandal in Bohemia.)

 

[JJPellin]

Lawrence makes fully lined slurry pumps. Pull up their manual for hard liners and it will have instructions for torque and heat up rate.

Johnny Pellin

 

[shashankTurbomachine]

What is the allowed solid particles size in manual?
Check and measure your inlet to pump

A well phrased question has answers in itself!!!

 

[shashankTurbomachine]

Generally upto 25mm for centrifugal pump

A well phrased question has answers in itself!!!

 

[Artisi]

"shashankTurbomachine -- Generally upto 25mm for centrifugal pump" utter nonsense.

It is a capital mistake to theorise before one has data. Insensibly one begins to twist facts to suit theories, instead of theories to suit facts. (Sherlock Holmes - A Scandal in Bohemia.)

 

[LittleInch]

Artisis,

It's a slurry pump. 25mm sounds quite small to me...

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

 

[JJPellin]

I was incorrect. Our similar pumps have a maximum heat-up rate of 150 F per hour as specified by the manufacturer. We also require that the pump temperature is within 100 F of the feed temperature prior to start-up. We are located in Minnesota and our design conditions are based on a minimum ambient temperature of -30 F.

Johnny Pellin

 

[Strong]

Does machine have high vibrations that could cause fatigue?

Does the system have any "water Hammer" or transient hydraulic pulsation during startup of shutdown?

Walt

 

[Artisi]

Have you had a complete failure as yet so as to involved a metallurgist in the problem with a close inspection of the material at the point/s of failure, or discussed it with the manufacturer - plus it would be nice to know who that is.




It is a capital mistake to theorise before one has data. Insensibly one begins to twist facts to suit theories, instead of theories to suit facts. (Sherlock Holmes - A Scandal in Bohemia.)

 

[billions]

My boss who's fairly involved and I as well have not heard of vibration issues

I think they're lookin into some failure testing but higher ups maybe trying to cover it up for their maintenance buddies by focusing on a small aspect or wrong issue

I did show pics to a mech engineer and we agreed on my theory, at least without testing it seems the most probable

There was a shutdown after install so plant reached ambient temps of -20C cus roof was off. Liner was installed with an impact gun over torque controlled method, and that combined with not bringing materials to ambient temp before install created good opportunity for cracks to develop if not already developed. Then, poor priming took care of the rest

Giw large slurry pumps

Will look into water hammer but not as far as I know. Will try to be at.pumphouse during the next startup

25mm particle size is nonsense. They are significantly larger but non issue because similar issue was not seen in upstream of this pump when the sizes are larger due to less impact/wear/ablation

Not pirated part, genuine part just might be different from.what they started with. Supplied by pump manufacturer or might be original model. Unsure from me

 

[Artisi]

Billions: good to see some "real" info at last - at least sounds like your on top of the investigation. I have absolutely no experience at all in these extremes of temp., so no comment -- however, certainly don't like the sound of impact tools to bolt up the liner, would suggets the fasteners are lightly torqued initially - the pump brought up to temperature and then final torque applied.

I've been out of the pump industry for more than 20 years, but re-called one company trailing very thick rubber-liners on grinding-mill primary discharge - (probably the toughest of the tough pumping applications), at the time it was looking very encouraging - final outcome ????. Could well be worth pursuing for your application.

It is a capital mistake to theorise before one has data. Insensibly one begins to twist facts to suit theories, instead of theories to suit facts. (Sherlock Holmes - A Scandal in Bohemia.)

 

[billions]

@artisi

Was getting more info as the week progressed. It was just my first week here as an EIT

Yes, that recommendation was discussed internally. Unsure of what's next, I believe some testing/inspection. The issue with that maybe that they cant lightly tighten the bolts because the liner is held up by a crane. To get the crane access to the liner, the rood must be removed. If the roof cannot be closed, then it cant be brought up with HVAC. Maybe a torch needs to be used to heat up liner plate to install bolts, then remove crane, install roof, then turn up HVAC and begin an acceptable priming procedure


I need to maybe look into whether the assembly can hold it's weight with light bolting and allow for complete torquing if crane is removed. These things are pretty heavy so it would probably be not possible


Appreciate your help and @JJpellin