Pressure Vessels internal forces

[SPLIT]

In a pressurized vessel with an open nozzle connected to a pipe, the opposed part to the opening of the shell is submited to a pressure distribution that generates a resultant force.The opening can not have an oposed reaction,but the pressure is transmited through the pipe , and somewhere is projected in an elbow or closed valve,it generates a force as well, which magnitude is pressure x area that is oposed to initial force applied to the internal part of the shell.So the vessel is pushed horizontaly by this internal force, and the nozzle is pulled in the oposite sense. ¿ Am I right ?

 

[PlantEng]

Can you clarify this a little? You have a horizontal tank with a nozzle connected to a pipe on one end which is then connected to a valve.

If the whole assembly is pressurized and the valve is closed, you have no net external forces and the assembly is not being pushed or pulled anywhere. The forces you are talking about are held in check by the wall of the vessel and pipe.

If you open the valve, you have a thrust situation which will apply a force parallel to the fluid/gas exit direction but opposite in sense. If there is an elbow, the resultant force direction will be parallel to the elbow exit direction buy opposite in sense. This is why relief valves should be adequately supported to prevent pipe deformation when they go off. The force on the elbow is not only the Pressure times the area you said but it is also the change in momentum of the fluid as it changes direction. Hope that helps