Maximum flange loading

[IFRs]

Is there a "standard" or "rule of thumb" for maximum flange loads that can be applied to a pump's flanges? I have fielded a question regarding maximum flange loading (not on pumps) that has no easy answer but I thought if there were some standard for pump flange loading I could pass it on and get out from under this question.

 

[SNORGY]

The rule of thumb that I use:

The flanged joint has to be able to hold up the weight of the heaviest operator in the plant in both the axial and transvrse directions.

Guys usually stand on them to reach other things...and two guys don't fit...so, design for the heaviest person.

I imagine there are better guidelines...

Regards,

SNORGY.

 

[micalbrch]

Check ASME Section III and ASME Section VIII, Division 2. We used that as a reference after calculation the nozzle loads with a finite element software.

 

[ColonelSanders83]

I have found that ANSI/HI 9.6.2-2001 has some excellent guidence on allowable pup nozzle loads.

http://estore.pumps.org/CentrifugalVertical-Nozzle-Loads-P7C5.aspx

Even if your punp isn;t listed its still a decent guide.

The only thing to be aware of is the the loads calculated relate to casting stresses. If you have a pump with a flexible casing you will see accelerated seal wear for these loads.

I find the standard especially useful to prod vendors into giving me reasonable loads. If I say I am using the standard as guidence until they give me better number, I seem to get information more quickly.

Just my two cents worth

A question properly stated is a problem half solved.

Always remember, free advice is worth exactly what you pay for it!

http://www.ap-dynamics.ab.ca/

 

[FMJalink]

IFRs,
I assume you want to know the maximally allowed nozzle loads and not the maximally allowable flange loads. Your question is very general, as it would apply from small plastic pumps to water circulation pumps for nuclear service. You did also not mention a specific pump type, for which the requested rule of the thumb should be applicable to all kinds of pumps. This generality makes already clear that there is no general role of the thumb for the allowable nozzle load on pumps.
Many pumps are built to standard specifications e.g. API, ANSI, ISO, DIN, etc. In many of these specifications you will find maximally allowed nozzle loads for the pump. If the pump is not built to such a specification you will require pump manufacturer data. If the pump is nearly equal to one of the standard specifications, you can assume that the pump would allow for the maximally allowed nozzle loads per standard specification, but it can be totally wrong.

 

[MJCronin]

To all:

Because this topic has been such a "festering sore" in the indusrty for so many years, I suggest the following:

Try to get vendors with competitive products to play off each other.

If vendor "A" publishes allowable nozzle loads for a particular line of pumps, ask vendor "B" why he cant meet or beat similar values.

This is basically been a commercial matter that has gone on for decades.....there is no reason for this.....except the for possibility of putting money in someones pocket.

I have seen companies paying more money for the nozzle evaluation of a pump than for the pump itself.

My opinion only....

-MJC

 

[rmw]

Flange loading goes beyond the flange or the nozzle. Most pump companies print dire warnings against excessive flange loading not having anything to do with the strength of the flange or nozzle, but having everything to do with causing deflections that create havoc with the rotating parts and alignment.

So I think that any pump I have ever seen (industrial grade pumps-not toy pumps) would have flanges and nozzles capable of much more loading than any manufacturer would want to see imposed on the pump.

rmw

 

[TenPenny]

If a pump 'manufacturer' cannot simply give you a document showing maximum allowable flange loads, they are not a serious pump company.

All of the 'real' pump companies have this information readily available, and I would consider the lack of this information as a sign of competence, or lack thereof.

 

[pumpking]

TenPenny you are right, this information is/should be readily available from pump manufacturers.

Also as rmw writes, excessive flange loadings do cause many problems with pump reliability, and as much as people design things correctly, you cant avoid the fitter who has eaten a few too many pies and chooses to stand on the pipework. Basic Engineering [principles need to be applied, make sure suction and dischrge pipes are fully supported close to the pump, and a crude test is to undo the flange connections, and make sure the pump will slide in and out of position with ideally no, but at least minimal movement.

Of course extreme of temperaturesa also has big effects on distortion so also bear this in mind if it is a process issue !


Ash Fenn

http://www.cdrpumps.co.uk