Can holes be made for pipes at the diameter change of pressure vessels?
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Dear seniors, I have a question: is it possible to directly drill a hole for a pipe connection at this reduction point? Reduction from 12” to 10” eccentric reducer, N6 pipe thread size 2”, thank you
It is generally not allowed; in cases like this, if a hole needs to be made, considering using a tee fitting directly would be an option. If a hole must be created, specific design calculations for the hole and appropriate reinforcement methods are required based on pressure and volume capacity considerations.
It doesn’t seem to be that many, but I have done similar work before – it involves devices of the type used for locking. There are holes for pipes on the vertical portion of such devices, and normal reinforcement calculations will suffice
It shouldn’t be allowed; no relevant regulations were found. I encountered a similar issue before and asked the design institute, and they said it’s not permissible
This is a ball receiving and sending cylinder; there’s no need to place the opening at the section where the diameter changes. It can be placed on the smaller-diameter tube, while the right-side saddle can be placed on the larger-diameter tube
In such an eccentric stub structure, there are usually welds at the bottom; if holes need to be made, it is necessary to take care to avoid those welds
According to the dimensions shown in the diagram, with the larger end having a diameter of φ325, standard seamless pipe fittings of type 12459 should be used for these joints. If that is the case, then there will be no such problem. If the joints are made by custom assembly, then it is necessary to follow the requirements outlined in 6.1.4 of GB150.3 in order to avoid issues related to welds: lol
It is a standard fitting of type 12459; all that’s needed is to create a 2-inch opening at the bottom. According to the GB50235 specifications for the construction of metal piping, the distance between the circumferential weld and the weld on the branch pipe must be no less than 50, and it must also be no less than the diameter of the opening. The total length of this fitting is 203 mm; after deducting 60 mm, the distance from the circumferential weld becomes only 70 mm. Is this too close? I also consulted the fitting manufacturer, who said that it’s possible to create a small opening, but a larger opening will affect the stress distribution in the fitting, and a stress analysis is required; if the strength is insufficient, reinforcement will be necessary
For funnels and similar devices, conical end caps should be used; openings can be made based on reinforcement calculations, and this does not violate the requirements of GB 150
Thank you. We also think it’s not feasible; it’s just what the supplier suggested, and we have some doubts
Does this type of opening method itself violate GB 150? No evidence was found in the pressure vessel regulations, but the design institute asked us to check those regulations, stating that it violates the requirements for pressure vessels: