Pipe end loads 1

[adiem]

I have a drawing showing a pump and outlet pipework from the pump, the drawing also shows position of pipe supports.

The pipwork exits the pump and immediately turns through 90 degrees and runs for 1500 mm and terminates at a flange, how would I calculate the loads and moments at the flange.

I have pressures and temperatures for the system

Thank you

 

[balu1]

My opinion is that you should calculate angular change of momentum for the highest (mass) flow in that 90-degree elbow. It acts coaxial with the elbow axis of symmetry, outwards. There is also a weight of that pipe but there is an additional support (on the pump side, I suppose)

The whole thing may be statically undetermined but you must use your ingenuity (that is what engineers are for, and what engineering is all about). Enjoy yourself.

 

[1974vet]

This is not intended to be a complete answer, but is for your consideration. You did not say what diameter the pipe was, which matters. The larger the diameter, the more difficult the fix, if required. For rough load values, take the temperature change and calculate the change in length of pipe. Convert this strain to a force, and moment on the pump. Pump mfgs will sometimes give you allowable forces/moments combinations; API has some allowable values for API pumps as well, etc. Vessel mfgs may give you some general info over the phone if the vessel is already in service re allowable nozzle loads, otherwise, the best practice is to calculate these loads for the vessel manufacturer and include in the specifications. If you have no other alternative and must make a determination as to whether the calculated nozzle loads and subsequent nozzle/vessel stresses are adequate, there are several methods available. Review the applicable piping code such as ASME B31.1, or B31.3, etc., and vessel codes ASME Section VIII, or applicable code. Get a good understanding of primary and secondary stresses. The piping should generally be designed such that the loads are carried mostly by the piping supports. Don't forget to consider the piping displacements as the temperature changes. There are many references as indicated in the above replies that speak to generally accepted good engineering practice for pipe routing such as this example. Once you are sure that the mechanical integrity issues are satisfactorily addressed and then look at the flow issues (safety first). Further modifications may be made to improve performance, decrease life cycle cost, etc., based on published data re standared good engineering practices. As usual, there are always exceptions that usually stem from the pumped material (or fluid) properties.