Shaft Delflection in API 1

[GaTechTheron]

I have exhausted many resources, and have not been able to come up with a maximum allowable shaft deflection in the API spec.

After looking through it, I came up with nothing. Is there no standard for this? Should I be looking more in the direction of the mechanical seal manufacturer instead? Thanks for the help.

 

[BigInch]

It seems to be a matter of what the customer is willing to pay for in terms of robustness corresponding to L/D ratio, rather than a set deflection standard, but

http://www.pump-zone.com

Nov 2004 has an article by Ross Mackay which mentions deflection limits and "many" industry standards. I don't know what those stds might be, but he do mention the limit at the seal,

At this point many
industry standards require the deflection of the
shaft to be no more than 0.002”(0.5 mm).
Owing to the potential for high levels of these
unbalanced hydraulic influences, the capability of
the pump shaft to handle such loads without excessive
deflection becomes very important. Consequently,
we may find that the design of the shaft
to limit the deflection of the shaft to 0.002”, may
prove to be inadequate.

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"Pumping accounts for 20% of the world’s energy used by electric motors and 25-50% of the total electrical energy usage in certain industrial facilities."-DOE statistic (Note: Make that 99% for pipeline companies)

http://virtualpipeline.spaces.live.com/

 

[bk19702]

From a mechanical seal standpoint, 0.002" is what the value we adhere too when discussing API pumps and deflection at the seal faces in general. I'd start there as a fairly consistent industry rule of thumb.

 

[GaTechTheron]

Thanks BigInch, and bk19702 for the tips. In the attached ISO13709 / API 11th; I actually have found where it notes the shaft deflection at the seal faces should not be anymore than 0.002". I have heard the 0.002 "rule of thumb" before, but I wanted to see if it was noted in the spec.

The document is attached for reference.

Thanks again.