Expansion joint thrust force

hi

I have a system with direct equipment to equipment straight connection with 9-meter pipe and I introduced an untied expansion joint with a limit rod to absorb the axial movement of the pipe. Here I didn't consider expansion joint thrust force at Equipment nozzle. However, I conveyed this thrust force to the equipment vendor and the civil department to design anchor bolt and foundation respectively. Is this approach correct?

Regards
Jai

Incorrect. Pressure balanced expansion joint needed in this case. Limit rod will not remove pressure thrust

Hi,engineer001ch

Thanks for your response.Since it is a straight connection how the equipment nozzle will experience pressure thrust?. In such case should i really go for pressure balance bellow ,if my equipment foundations are well adequate to with stand thrust load ? please refer attached figure for more clarity.
NOte: nozzle will see pressure thrust ie (Pressure * area between effective dia and internal dia of the bellow) which is negligible.

Thanks

I think nozzle load will be Pressure * effective dia area. Not "area between effective dia and internal dia of the bellow".

In case you have provided proper guides on both sides of pipes and the piping on a straight line your approach is correct.

You may not need the guides in case the distance is short enough and/or the system that you provided does not introduce bending moments on the nozzles.

small correction :
NOte: nozzle will see pressure thrust (Pressure * area between effective dia and internal dia of the pipe) which is negligible.

I think you are wrong.
"True" force will be Pressure * area between effective dia and internal dia of the pipe, but "effective" nozzle load will be Pressure * effective dia area.
https://whatispiping.com/bourdon-effect-true-and-effective-axial-force
https://whatispiping.com/restrained-and-unrestrained1

Additionally your small correction is correct in case of a straight line approach, I forgot to mention in my previous post.

It seems that I lost my previous post somehow.

Shortly, ı was questioning why you have selected a straight line approach since I found 9 metres of distance long since you did not mention about diameters of pipe and diameters of vessels, temperature and pressure in the system. If the diameters are small I would use an expansion loop instead.

Hello,

Can some one provide some case studies or solved examples like those provided by Caesar II Tutorial?

Thanks,

Nour Eldin

Assuming the expansion joint is infinitely stretchable, the expansion joint itself would expand out nearly to F=kx where F=PAaff, if it's just an expansion joint and two blinds.

If we push both ends back together to initial state, we need to exceed and then meet F=kx.

If we want to push it further - such as taking on thermal displacements from pipe, then we have additional x to include into our analysis.

Of course, our metal isn't unobtainium, and it will also be inclined to flex. So the expansion joint will absorb some fraction, the pipe will absorb some fraction, the vessel wall will absorb some fraction, and the bending from nozzle to vessel base will absorb some fraction.

They're all flexing together in series, so 1/keq = 1/k1 + 1/k2 + 1/k3... thus resulting in a total load somewhat less than P*A+k(expansion joint)*x(thermal).

In the case of tie joints, you have a non-linear scenario where F=kx if x is compression and F=(k1+k2)x when in tension, where k1 = rubber and k2 = tie rod.