Flange issues with mixing equipment
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I recently designed a pressure vessel, with the mixing system being supplied by an external contractor. Is the flange on the head considered a primary pressure-bearing element?
We consider it as follows: if the inner diameter of the flange is ≥ 250 mm, then it is considered a primary pressure-bearing element; however, since the inner diameters of the flanges on the lids of mixing vessels are not large, we refer to the outer diameter of DN250 flanges to determine whether such elements are primary pressure-bearing elements.
We usually designate them as the main stressed components
It belongs to the main compressive elements. The reason is that, based on the outermost edge of the equipment flange, this value is usually greater than 250 mm, which corresponds to the diameter of the opening in the container head. For reference!
Those with an outer diameter greater than 250 should be treated as primarily compressive members
In that case, it is a type where the flange is embedded in the head; in fact, 60% of the cases do not have such a structure, as there is a section of pipe inside the flange, and that pipe is considered an opening in the head. If it’s embedded, then it definitely counts; as for the type with connectors, I think it doesn’t really matter whether it counts or not – it has no impact on the pressure resistance.
The flange is certainly a compressive element, and its design is very important; for its calculations, reference can be made to HG20581
The flange serves a reinforcing purpose and should be the main compressive element.
The flange is at least as important as the reinforcing ring; it not only serves to bear pressure but also supports the frame and similar components, and is therefore a compressive element.
1. In mixing equipment (vessels), the flanges that connect the upper part of the vessel to the frame rarely come with a section of pipe attached to them. Apart from embedded flanges, another common design is one in which the structure is directly welded to the holes in the upper cover where the agitator is located; for details, refer to the relevant illustrations in section 3.1 on design types in HG21564 \"Mixing Drive Devices – Flange Connectors\". 2. The connection methods between the lower part of the mixing equipment (vessel) and the discharge valve (or bottom valve) are embedded flange and pipe flange ； The former is mainly used in situations where strict requirements exist to completely remove all remaining material in the tank, while the latter is used in cases where such strict requirements are not applicable. 3. Whether it is the main pressure-bearing component of the vessel, or whether it should be determined based on whether the nominal diameter of the pipe fitting is greater than or equal to 250 mm (see Article 25 of the Vessel Code). For discussion!
The flange is certainly a compressive element, and its design is very important