Does a conical head with flanges at both ends under internal pressure require a reinforced section for the cylinder?
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Calculation of internal pressure for the lower head of the inner cylinderUnit of calculation:
Design conditions:
Schematic diagram of the conical shell:
Calculated pressure, Pc: 0.93 MPa
Design temperature, t: 100.00 °C
Diameter at the larger end of the conical shell, Di: 2800.00 mm
Diameter at the smaller end of the conical shell, Dis: 39.00 mm
Radius of curvature at the larger end of the conical shell, r: 280.00 mm
Radius of curvature at the smaller end of the conical shell, ri: 50.00 mm
Calculated internal diameter of the conical shell, Dc: 2520.01 mm
Half-apex angle of the conical shell, a: 60.00 °
Material name: 0Cr18Ni9
Material type: Sheet metal
Allowable stress at test temperature, s]: 137.00 MPa
Allowable stress at design temperature, s]t: 137.00 MPa
Yield strength at test temperature, ss: 205.00 MPa
Negative deviation of steel plate, C1: 0.00 mm
Corrosion allowance, C2: 0.00 mm
Weld joint factor, f: 0.85
Calculation of conical shell thickness:
Thickness of the conical shell portion: 20.16
Thickness of the transition section, dr: 15.09 mm
Coefficient K: 1.3499
Thickness of the transition section connecting to the larger end of the conical shell, dr: 20.16
Factor f: 0.90
Calculated thickness, dr: 20.16
Additional calculated thickness, dr: 0.66 mm
Is reinforcement needed? Yes, reinforcement is required.
Stress enhancement factor at the smaller end of the conical shell, Q: 4.21
Length of the reinforced section of the conical shell: 7.16 mm
Length of the reinforced section of the cylinder: 5.06 mm
Calculation results:
Nominal thickness required for the conical shell: 21.00 mm
Nominal thickness required at the larger end of the conical shell: 21.00 mm
Nominal thickness required at the smaller end of the conical shell: 2.00 mm
May I ask whether the thickness mentioned for the larger end of the conical shell refers to the conical part or the cylindrical part? The thickness of the cylindrical part is 12 mm.
The thickness at the larger end refers to the wall thickness of the section where the cone meets the cylinder.
For a conical head of 24 mm and a cylinder wall of 12 mm like this, is it necessary to add a transition section?
Personally, I think a transition section is needed; it’s not possible to cut edges on the conical shell, otherwise the strength of those cut areas will not meet the required standards
It doesn’t seem so. The larger end of the conical shell refers to the thickness at the apex of the cone, while the folded edge is the one that is directly connected to the cylinder; generally, the greater of these two values is taken. When the thickness is not uniform, it is necessary to consider the transition between the fold and the cylinder. There seems to be no need for a transition section either; a transition section can be considered if the condition of having no folds permits it. This post was last edited by ljfdd2002 on 2009-2-4 09:19.]
Based on the calculations above, the conical shell requires a thickness of 24. Can such a thick conical end cap be folded over? Especially at the smaller end – it’s definitely not possible to do that during processing. If it’s not feasible, how should it be designed? I would appreciate advice from experts
According to GB150, local reinforcement should be applied to the small end of the conical shell
This post was last edited by letitbe on 2013-1-29 at 22:13. A small conical section is forged to form the minor end; the remaining conical sections are welded together with the major end, and after flanging, they are welded to the forged section. . Personally, I think you might be using a structure with folded edges on both the big-end and small-end formats in order to comply with GB25198 Why not calculate by folding the larger end and leaving the smaller end unfolded? In this case, the small end can be directly connected to a pipe fitting or directly to a butt-welded flange