Dear Reza59,
Regarding to settlement, it is usual to use exp. bellow. Consult w/ the vendor the allowable lateral movement, moment on the bellow. Below is my opinion:
I have to use a variable spring near tank due to settlement.
I think the software apparently does iteration by moving to related spring FIG table to have variable type based on load variation. If can't find one it will try two. If still can't find it will select the constant type one.
and sustain case are bellow the allowable but as the density of fluid is high in case that the pipe is out of fluid(WNC+P+H and WNC+P+H+D) due to decrease in weight of the system
WNC+P+H; What is the internal pressure you have considered for this case?
WNC+P+H+D; What is the displacement you have considered for this case? is it from the settlement predicted by civil/soil guy? Take a close discuss w/ them.
spring moves upward and imposes large load and moment on nozzle
In what case? I'm doubt about this except for the represent of Temperature. But need to see your support configuration there. Sorry if i'm wrong then. Would you please to post the graphic of your model isometric to your next reply? it seems many of us are very interesting w/ this case.
Can I declare the manufacturer of spring to place something like limit stop to restrict the movement of spring
Try using spring travel at pre-spring design? expert may suggest...thx