On the calculation of reinforcement for openings
Thread Content
What’s the reason why I can’t upload pictures? I just want to ask: For a hole made in a circular cylinder, with a conical pipe connected to it, how is the reinforcement for such a hole calculated?
Conical holes are made in the cylinder, and it is undisputed that the area of the cylinder that is weakened corresponds to the large cross-section at the base of the cone. As for the calculation, regarding the reinforcement area taken over, I think it can be calculated based on the corresponding projected area
Thank you for your reply! This is the first time I’ve encountered such a situation, and I was thinking that using the maximum size for the opening isn’t feasible, as relying on the maximum diameter of the cone for effective reinforcement of the pipe isn’t appropriate; on the other hand, there’s no basis for using a smaller size. So what approach should be taken to find a compromise? I have seen actual examples of this type of device, but I haven’t seen how to calculate it.
For the cone nozzles, it is the value of A2 that affects the opening reinforcement calculation. Since it is a non-cylindrical fitting, calculating the area of A2 becomes a hassle during the computation process. If possible, A1 should be used to compensate for the area of the opening; it is necessary to calculate based on the larger hole, as doing so based on the smaller hole would be unreasonable, resulting in an even greater difference in the area of the opening
This post was last edited by cxd11888 on 2018-6-4 at 12:20. Hello, teacher – does that mean we should use the shell for reinforcement as much as possible, enter the pipe opening dimensions with larger values, and set the protrusion height to a lower value (for example, 10 mm)? However, the software will display a message stating that the actual protrusion length of 10 mm is too short; it must be increased to at least 41.857 mm.
On a conservative estimate, without taking into account the area where the excess thickness is used for reinforcement, the diameter of the opening will certainly be based on the largest possible diameter.
Are holes size 219 being used? Are 8 wall thicknesses entered? Complete your parameters and take a look. Diameter, pressure, temperature, material, hole size.
If calculation is necessary, it can only be done by hand to modify the SW6 calculation sheet. 1. The thickness of this conical section fitting can be calculated using the components ； 2. Then calculate the difference between the effective thickness of the conical section fitting and its calculated thickness, based on your actual nominal thickness ； 3. Calculate the effective reinforcement A2 of the tapered pipe based on the effective overhang length. 4. Since for the housing, it depends only on the size of the opening and not on the nozzle, A1 remains unchanged. 5. The total reinforcement area A is calculated by comprehensive consideration: A = A1 + A2 + A3 + A4
I think we can draw on the reinforcement design concept from ASME VIII-2 Fig.4.5.8 for axial nozzles on conical shells
This nozzle is used in the shell side of fixed-tube plate heat exchangers. Design pressure of the shell side: 0.6 MPa. Design temperature: 60°C. The shell of the shell side is made of 20# seamless steel pipe with dimensions of φ325×8; the pipe flanges are of type WN150 (B) -16 RF. A conical fitting is connected to these pipe flanges, and this conical fitting is to be fabricated from Q245R material with dimensions of φ219/159×8; the protrusion height of this fitting is 220 mm.
It should be calculated based on the maximum diameter of the projection of the intersection line between the cone tube and the housing.