Pump heads - Cast iron vs. Fabricated Steel Vertical Turbine pumps 1

[DrLewinstein]

Hi, gang!

I am working on a WTP design including new High Service pumps. A former operator told the client that he should insist on cast iron pump heads, that fabricated steel ones would ultimately deform or flex and cause problems.

Any thoughts?

Thanks!

 

[ashtree]

DrLewinstein

Depends on a lot of things but i am assuming that when you say fabricated steel heads you are referring to the many manufacturers that now build multistage pumps out of stainless sheet with various bits bolted on or supported by cast iron brackets , base plates etc.

Those style of pumps generally work well and give many years of service, if selected correctly.
However the same applies to a cast iron pump.

Regards
Ashtree
"Any water can be made potable if you filter it through enough money"

 

[bimr]

That is not much to go on. If you have some actual experience, use that as a reference.

You should be aware that the manufacturers are constantly updating their products and it is be difficult to find the same equipment just a few years later.

 

[DrLewinstein]

Thanks, gentlemen!

 

[Artisi]

I would suggest that there is nothing wrong with a properly engineered and fabricated steel discharge head assembly for a VT pump. If steel is suitable for the pump / discharge head column why not the discharge?

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.)

 

[1gibson]

A former operator told the client that he should insist on cast iron pump heads

Thought - his/her preferred pump vendor used cast iron heads, and the operator wanted to spec everyone else out.

If you think a fab steel head will be floppy, spec a minimum wall thickness.

 

[TenPenny]

In my experience, the question of cast vs fabricated heads depends on the pressure rating and, generally speaking, the size of the motor. As the motor size gets large, you won't find any cast iron heads. (Also, as an aside, many manufacturers are going to ductile iron for cast heads, not cast iron.)

When you're looking at at 1500 hp vertical motor on a 30" pump, you'll be hard pressed to find a cast head.

Face it, the manufacturers actually know what they're doing.