Stress calculation

[Sabina_1989]

Hi!

I am dealing with the stress analysis in Caesar2 and need to calculate a system consisting of two pumps and the piping on the suction and the discharge side. A picture of the system is attached. I need to decrease the axial force on the discharge nozzles of the pumps, which is too high.

The discharge lines are shown on the right side. The springs at the discharge pipe line (shown in purple) do not help to decrease the axial loads. Do you know why? And / or do you have a solution?

Conditions of the system:
The design temperature is 87 grad.
The operating temperature is 55 grad.
The pressure is 6 bar.
DN 50.

If you have any questions please let me know.

I hope you can help me , thank you in advance and with best regards!

Sabina

 

[KevinNZ]

With enough up force from the spring hangers the gravity force on the pumps will decrease. Check your spring rates and preload.

 

[DSB123]

Are the loads on the discharge Up or down?

 

[XL83NL]

With this pressure and temperature, it should be fairly simple to reduce the nozzle loads. Nothing 'big' going on. Kevin has given the first answer to a solution.

Im not a CII-user, but it seems you have a V-stop (which may experience lift-off and hence become redundant), and do you also have a bellows in place?

 

[Sabina_1989]

Firstly I would like to say thank you very much for your answers!!!

1) When I choose stronger springs it helps me to decrease the loads in "hot" Load Cases.
But what i don't understand is why my springs in sustained condition don't work at all. In this "Dead weight" case (pipe weight + insulation)?

Could you please explain me what could be the reason for such work?

2) The loads on the discharge line.

I describe start-up/shut-down conditions for pumps. So, the loads on the first pump(left one)work in both directions: "+" in Minimum Design Temp.case (5 grad) and in Sustained Cases. All another working cases have "-".

The second pump (the right one)works mostly "+" and only in Sustained Cases has "-".

3) This green arrow is a loose support(for weight only).
And this two green things on the vertical pipe is not a bellow. These are orifice flanges.