PRESSURIZED CYLINDER FORMULA

[gorkus]

Which is the formula to calculate the minimum wall thickness required ,of a pressurized cylinder?
Can I take the pump casing as a pressurized cylinder in order to calculate "minimum wall thickness"?
Many thanks in advance

 

[metengr]

Yes. Pump designers have used this approach. If you have access to ASME Section VIII, Div 1 you can use the
formula(s) for a cylinder under internal pressure. If not, your second option is to use Barlow's formula below with some level of safety factor;

hoop stress = [pressure *outer radius/wall thickness]

Set the hoop stress default value as a percentage of yield strength (50%) to assure no permanent deformation. The above equation assumes a thin wall cylinder (based on a ratio of r/t greater than 5). More elaborate equations are used for thick-walled cylinders.

 

[gorkus]

If the material is cast iron ( GG-20) what will be the hoop stress value in order to calculate wall thickness.?
Thank you very much indeed¡¡¡

 

[stanier]

If you are calculating the wall thickness of a pump case you may need to consider it to be a thick wall cylinder. The formula is different.

 

[metengr]

Before going forward, what is the pump design and what are your service conditions?

 

[gorkus]

Its a vane pump to work with liquids such as: gas oil , petrol ,oils, etc.Its a P.D pump.The service conditions are ,not high viscosity , rpm < 650rpm and working Tª of <135ºC, non corrosive ambients, maximum pressure of 10 bar.