ANSI Mag Drive Maintenance Expectations 2

[YungPlantEng]

We have a large selection of mag drives at our site, some for tank farms and some for batch vessel recirculation. Talking with vendors I’ve always kind of understood that there isn’t too much to maintenance with the pumps - in that rebuilds don’t occur and we just replace wet ends on failures (which have always ended up with the containment shell and impeller assembly fusing together in a catastrophic failure.

I was wondering if replacing wear rings and thrust collars on smaller rebuild frequencies may reduce impact or frequency of these failures. It’s hard to believe nearly every failure is a result of mis operation, as some of these pumps last 7 years and some last 2.

Not sure if anyone else has experience on this. Thanks!

 

[TugboatEng]

The mag drive eliminates seal maintenance. All of the other parts have the same maintenance intervals of conventional pumps if similar construction.

Mag drive pumps are especially sensitive to misoperation as there are additional components in the wet end to damage (bearings).

Mag drive pumps are uniquely sensitive to damage from ferrous particles in the fluid.

 

[TheHandModel]

There are closed coupled mag-drive configurations that don't have a bearing frame. If they eliminate the bearing frame then they eliminate shaft alignment as well as bearing wear and oil related items(checking/maintaining level, sampling/testing, and oil changes). Most designs I have seen also do not require any sort of impeller shimming you experience with open/semi-open impellers. Carbon bushings will slowly wear over time but if they are using silicon carbide your life expectancy would be based on operators/process stability.


I think repair vs wet end replacement comes down to the type of damage and the cost to decontaminate the parts. For something non-hazardous, repairs might make more sense for field serviceable products depending on product complexity, maintenance familiarity with the product, and available resources.

 

[YungPlantEng]

Thanks Mr HandModel. Yes these are the smaller direct coupled mag drives where the only real wear parts are the bushing and impeller. Techs had a good laugh when I tore open a pump we were relocating to find out the bushing was less worn than myself