Do internal floating roof tanks require core-equipped manholes?
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I saw in the discussion threads that some say it’s necessary to add it, while others say it’s not required. So is it really necessary to add it? I’ve never seen an internal floating disk; does it have manholes just like an external floating disk?
Which specification requires it? The manhole with a core is there to facilitate maintenance when the inner floating disk drops, right? But I see that many internal floating disks now have a separate maintenance access opening. So, is it possible for an ordinary person to enter the tank through this opening and then climb up via the separate maintenance access on the internal floating disk to carry out maintenance work?
It’s better to add it, though some don’t; personally, I think it’s better to include it
Compared to floating roof tanks, the cylinder that connects the manhole of conventional tanks to the tank wall passes through the tank wall, and such manholes are not conducive to the lifting and sealing of the floating deck. A core-manhole features an additional core plate inside the manhole cover, with a curvature equal to that of the tank wall, and it is level with the tank wall. To facilitate opening and closing, a rotating arm and lifting lugs are also installed on the hole cover in conjunction with the tank body, ensuring that the manhole cover remains attached to the oil tank during operation.
It needs to be added; otherwise, air leakage will occur when passing through the manhole, and the sealing capsule extending into the manhole will act as an obstacle.
Thank you for your reply; I added a manhole with a core
I’ve learned it, I’ve learned it. Thank you for your reply
It is generally added, after the floating disk has dropped to the bottom, on the cylindrical wall at the upper part of the floating disk; it is mainly used for checking the inner floating disk in cases where a displacement tank is not used. The core is mainly used to prevent severe friction of the floating disc seal elements as they pass through the manhole, which could cause damage to those seal elements
Prevent the sealing strip from entering the manhole cavity, as this may affect lifting; manholes on the tank wall floaters should use core-equipped manholes. It’s not the manhole on the floating roof.