Gimbal Joint (expansion) 2

[Vladimir99]

We have a crude tank installed for 20 years. We will replace the inlet line. At the entrance of the tank there is a gimbal joint. I am wandering if we should replace it.The tank is not sinking anymore into the soil.

Thanks,
Vladimir99

 

[gr2vessels]

Vladimir,
The inlet piping replacement may or may not exclude the stresses are generated by the this piping (if the expansion joint was installed to compensate for additional deflection generated by piping expansion). If you are confident that you can anchor positively the inlet piping, excluding external loads on the inlet nozzle, then obviously you can hard pipe the line to the nozzle. As caution, however, I wouldn't do it, for the sake of saving few cents on gimbal, to risk big bucks on a burst tank.
Before you do the hard piping, measure the inlet nozzle rotation due to hydraulic load of a full tank and calculate the stresses generated by the hard piping resisting the rotation of the nozzle, compare to allowables or the yield, project a improbable scenario of other deflections due to seismic or other loads, when satisfied that nothing could go wrong (reasonably), then do the hard piping.
cheers,
gr2vessels