I dont understand it. Ive read this on most of the posting related
to piping load. Everytime you get a number that is high, the very
first reaction is to go back to C2 and fine tune the pipe nozzle
model to make the calculated piping load satisfy the allowable. This
is very reactive approach. This is nothing more than an excercise in
computer tech. We're overlooking the engineering fundamentals.
And what i have observed in most cases is that you ended up with a
design that is complicated. And by the time you figure whats
happening, your already trapped in the maze of computer prntout. And
the result is a design that is not reliable. Because of the fine
tuning, you just made the equipment that your trying to protect in
the first palce with very little margin of safety and therefore
vulnerable.
You see, the pump generally is divided in to three distinct parts.
The pump body, the foundation and the base skid or pedestal. What do
you ntice?
Well the pump body is robust and stringer than the pipe. The
foundation is massive and heavy and therefore stiff. The skid - is
just that. a base plate built only when one purpose, to support the
weight of the pump hence can only take so much piping load. Its the
weakest link. So to my opinion instead of fine tuning your pipe
nzzle model, my i suggest that you check the 6th edition of the API
610 or you discuss your findings with the rotating equipment
ecingineer or with the pump vendor. Maybe the answer is there.
Specifying a double or triple stregnth base plate increases the
piping load by 2X or 3X at almost no cost to you.
- In PipingDesign@yahoogroups.com, Rajesh_V_Balapure@r... wrote:
>
>
>
> Try "Offset Modelling" for trunion & check the difference in
Caeser
> package.
>
>
>
>
>
>
> "mechengr1977" <mechengr1977@y...> on 11/21/2002 06:09:32 PM
>
> Please respond to PipingDesign@yahoogroups.com
>
> To: PipingDesign@yahoogroups.com
> cc:
> Subject: [PipingDesign] Re: pump nozzle loads
>
>
> try Caesar II USer Manual and their excellent Training Manual. or
> use a double strong pump base - amazing what a lil changes in the
> pump skid does to the nozzle load.
>
> --- In PipingDesign@y..., Geoff Stone DD&D Australia
> <blenrayaust@y...> wrote:
> > Hi Shivakumar,
> >
> > I would suggest that you may need to re arrange the piping in
your
> model.
> >
> > Another common problem in modelling such nozzles is if you make
> them absolutely
> > rigid then enomoius loads and moments will arise. If you put the
> smallest of
> > "gaps" in the restraint the nozzle will behave as it would in
> practice and
> > accomodate a small amount of strain say .010". You may find that
> the loading is
> > more realistic.
> >
> > Try running the model without this restraint and check the
strain.
> WEokr out
> > what leg of the piping is causing the problem and modify the
route
> or support
> > it differently by the use of spring hangars etc.
> >
> > Geoff Stone
> > --- shivakumar angadi <shivku_2000@y...> wrote:
> >
> > <HR>
> > <html><body>
> >
> >
> > <tt>
> > Dear friends,<BR>
> > <BR>
> > I'm doing analysis for piping where pump is getting<BR>
> > connected at one end. I have fixed the pump nozzle as<BR>
> > fixed point. Since there was a huge value for moment<BR>
> > 'Mx', I have introduced one Ry, rotational restraint.<BR>
> > Now all the moment has been transferred to this<BR>
> > restraint. It is not possible to design the support<BR>
> > for such a huge moment. Please advise any other method<BR>
> > to reduce these moments.<BR>
> > <BR>
> > Thanks<BR>
> > <BR>
> > shivakumar<BR>
> > <BR>
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> >
> > <br>
> > <tt>
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> Discussion List sponsor: Texas Flange - a good source for
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Received on Fri Dec 06 22:41:00 2002