Hi

I have the following quarries.

1. In API 610 nozzle allowable loadings, the force values are listed for different nozzle types. But the nozzle allowable moments are same for all three types of nozzles. Why is it so?

2. In a side discharge pump nozzle (nozzle inline with Z axis), i am analyzing with Y support and a Guide at the first elbow. In real situation for this support arrangement there won’t be any rotation about z axis. In that case if I provide a RZ restraint, is it represents the real support arrangement? If not on what support arrangements we shall use RX, RY, RZ restraint types?

Hi Muth
Answering your questing 2 , Why there will not be any Rz if you provide only rest +guide support at elbow ?
Let us think after elbow pipe go up then again elbow & pipe go towards X direction then pump nozzle will get Rz moment .
Let caesar to think & calculate all this & you provide support as it is . No Rx , Ry Rz if you are not putting a anchor support.

Hi SHR, thank you for your immediate reply.

The pump routing is same as you assumed. here my question is, if i put a hold down with guide as my first support; it supposes to absorb moments and forces caused by the pipe laid after this support, doesn’t it? Why does my pump nozzle getting over moment.

when shall we use RX,RY,Rz Kind of restaints in pipe stress analysis?

No your support will not arrest any moment. It will arrest force only. So pump nozzle you may get x (reaction type)force in opposite direction and Z moment.
If you want to reduce Z moment at pump nozzle try to put limit stop after second elbow ( where pipe is going towards X direction).
Only when you are using anchor support Rx Ry Rz will be used.
Anchor equivalent to x Y Z Rx Ry & Rz.

Muth R,

Answering your first question ....

The primary aim of the allowable limits set in Table 4 is to restrict shaft misalignment due to external loads.

A moment acting on a nozzle in any location or orientation will be reacted at the pump pedestal, and it doesn't matter where that moment is applied on the pump. In contrast, a force applied in a given direction will cause a moment dependent upon it's position and orientation. Thus, allowable forces differ for the various pump types.

Thanks MoverZ
For your valued information.

Thankyou MoverZ.