Last Updated: 2022.7
For Internal Pressure
Internal Pressure: The internal design pressure (pressure on the concave side). This value is gauge pressure. When “Solve for Thickness” is selected, this value is an input and should not include static head. When “Solve for Pressure” is selected, this value is a result. In the latter case, it represents the total internal pressure (design pressure plus head) that the component can handle and meet code in the absence of any other loadings. This defaults to the lesser of the cone or cylinder internal pressure. It can be changed.
Static Head: The internal pressure (pressure on the concave side) resulting from the static head of the fluid. The user must determine this value and input it accordingly. It will be added to the Pressure input and the sum will be used in the internal pressure calculations for the component. This field will not be present when “Solve for Pressure” is selected. This defaults to the lesser of the cone or cylinder static head. It can be changed.
Axial Load: The load per unit length on the junction. The check box to the right of the field toggles this value between a tensile load and a compressive load. This value affects the Internal Pressure case only.
For External Pressure
External Pressure: The external design pressure (pressure on the convex side). This field is disabled and locked to the value from the cylinder at the junction.
Axial Load: The load per unit length on the junction. The check box to the right of the field toggles this value between a tensile load and a compressive load. This value affects the External Pressure case only.
Use Custom A: Checking this box will enable the "Custom A" field for input and the Custom A value will be used for A in the Line of Support calculations instead of the A value determined by the software.
Custom A: This field is only available when the "Use Custom A" check box is checked. This allows the user to determine override the A value determined by the software and instead use one the user has determined from the external pressure charts.
Use Ln Based Interpolation: Checking this box will use natural log based interpolation instead of straight line interpolation when determining A from the external pressure charts. Both straight line and natural log based interpolation are considered valid, though it can be argued that natural log based is more accurate for the external pressure charts.
Juncture is a line of support: Select this box to consider the junction as a line of support for the design of the vessel for vacuum. With this consideration, the juncture must pass additional requirements. When the juncture is considered a line of support, the code does not require that the cone required thickness (external pressure) be at least that of the adjacent shell.
Check Cone Pe tr vs. Shell Pe tr: When the junction is not a line of support and this box is selected, the cone tr for the external pressure case must be at least the shell tr for the external pressure case or the junction analysis will fail. Clear this box to avoid performing this comparison. See UG-33(f) for more information.
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