Expansion Case x Friction Force x Pump Nozzle Allowable

Hi all,

I need help to solve a problem:

In a water pump system, consider pump as a bilateral nozzle (both horizontal). So, due expansion case, when pipe expands and due friction force by support, a reaction force transmits efforts against discharge nozzle which is higher than allowable by pump.

I think the better way to reduce this force is eliminating friction force is replacing support for a rod. Am I right?

Data:

Discharge Nozzle Diameter: 20"
Pipe diameter after: 32"
Pressure: 5.8 bar
Temperature variation: 5° C

Also, I can't use expansion joint, because F = P*A will be higher than force due friction.

Somebody can help me?

Thanks in advance,

Miyamoto

PTFE is one option. You can check. But is strange you have only 5 degree temperature variation. At this delta temperature is realy necessary to have a thermal case?

Regards,

Dear,

Indeed the displacements isn't high, but any displacement results in a giant forces due large diameter. So if I use MU as 0.3, means friction forces will be high too.

I thought in a PTFE plate to reduce friction coefficient, but I think this plate will wear off soon.

Anyway, follow attached the model.

Look at dischards nodes: 2050, 4050, 6050.

Considering the fact that I need to use expansion joints, what I can do to the system work right?

Heeeeeelp!!

Thanks,

Miyamoto

Read this:

http://65.57.255.42/ubbthreads/ubbthreads.php?ubb=showflat&Number=32822&page=2

I also think that for 5 degrees temperature variation, thermal analysis is not required.

You can try this.

Regards,

Very interesting..

So, I can simply check if SUS Case is OK, disregarding temperature due delta T is very low?

In pratice, thermal expansion with this small temperature variation probably vanish in gaskets or flange "gaps" from installation, or others.

Is this right?

Regards,

Miyamoto

You can try also other low friction materials with extended lifetime. I think you can find some acceptable.

Regards,

Dan,

Thank you very much. It will be very usefull.

But, I have other doubt.

In that topic you mention, they talk about vertical discharge.

For vertical discharge, it's possible delete fluid density in vertical way and keep horizontal normally. Probably it will reduce weight in dischard nozzle due fluid not actuate as vertical down force?

Thanks again,

Miyamoto

It will eliminate the necessity of instalation of spring hangers...

To be honest personally I’m not sure if is really like this. Maybe it is at some degree.
But maybe will not change much the effect it has on the pump.
Most of the times, the discharge have an elbow quite close to the nozzle.

Regards,