Manhole material issue
Thread Content
Why are the horizontal and vertical lift lids with neck butt-welded flanges not available in stainless steel, while the flat-welded flanges are all available in stainless steel?
The cost issue! This can be determined by the user or the designer!
You can take a look at HGT 21594～21604-2014 for stainless steel manholes and handholes
If needed, you can design it yourself.
Unless the user has special requirements, this structure adopts a lining design. If necessary, as mentioned above, you can select pipe flanges and flange covers of the appropriate grade in accordance with HG/T20592.
Thank you all for the explanations. I am working on a low-temperature container, and the equipment is made of stainless steel. When choosing manholes, I found that those with necked flat-weld flanges were available in stainless steel, but those with necked butt-weld flanges were not. In the end, I selected the flanges and pipes myself and designed the drawings on my own
For minus 120 degrees, what kind of manhole should be chosen? Is it necessary to design one oneself? The same goes for high-pressure applications – there are no standard manholes available, so design ones manually, which is very troublesome
In low-temperature operating conditions, no special considerations are made from a structural perspective; the main approach is to use materials suitable for low temperatures, such as 16MnDR. But if it is -120°, stainless steel is recommended, such as 304, 316, and the like. For high-pressure applications, WN-style manhole flanges are definitely the choice. It is important to pay attention to the selection of the sealing surfaces and gaskets; there are many mature options available for high-pressure sealing surfaces and gaskets, so it’s sufficient to choose one that is suitable. If you’re not sure, I recommend searching on the forum first :)
The material and medium are related to the operating conditions, and have nothing to do with the selection process. Another factor is cost; AK versions are available in steel as well as gold.
We generally design them in accordance with American standard pipe flanges