API 650 Tank with a Rolled Bottom Ring
API 650 Tank with a Rolled Bottom Ring
(OP)
I have a 304 Stainless API650 Tank, Tank is designed for 2.5 psig. Capacity is about 10,000 gallons. Diameter is about 12 ft. The tank sits on a sloped concrete pad. (The bottom of the tank is sloped to drain out.
the Hold down ring has began to curl up, in some places it is 1" off the concrete, despite the concrete anchors currently in place. I am wondering what should I do with it? It is currently not leaking. I am wondering if I should drill anchor bolts into the flange between all of the existing bolts and try to pull it back down. Or if I sould leave it the way it is, maybe just caulk around the outer ring to keep snow and ice from getting in there. Any thoughts?
Regards
Stonecold
the Hold down ring has began to curl up, in some places it is 1" off the concrete, despite the concrete anchors currently in place. I am wondering what should I do with it? It is currently not leaking. I am wondering if I should drill anchor bolts into the flange between all of the existing bolts and try to pull it back down. Or if I sould leave it the way it is, maybe just caulk around the outer ring to keep snow and ice from getting in there. Any thoughts?
Regards
Stonecold





RE: API 650 Tank with a Rolled Bottom Ring
RE: API 650 Tank with a Rolled Bottom Ring
RE: API 650 Tank with a Rolled Bottom Ring
RE: API 650 Tank with a Rolled Bottom Ring
I have finally had a chance to put some pictures together to show you guys the problem with this tank.
I put them all in a word document, I hope you can open it.
Let me know what you think might be happening.
One more thing the specific gravity of the fluid is only 0.7 so I don't think that is a contributer to the problem. The tank did not have this when it was originally installed.
Regards
StoneCold
RE: API 650 Tank with a Rolled Bottom Ring
Solution - design anchorage that is attached to the shell in accordance with API 650.
RE: API 650 Tank with a Rolled Bottom Ring
RE: API 650 Tank with a Rolled Bottom Ring
I suspect that the 2 psig nitrogen is the cause of the bottom ring problem.
Perhaps the nitrogen pad was added to the tank some time after the tank was originally put into place ?
This type of sloped-bottom tank deserves proper anchorage.
Pictures can help a lot !!!
RE: API 650 Tank with a Rolled Bottom Ring
About the only way to force it down would be to put anchors in the concrete around the rim and then make a hold down clamps from steel plate to try to squeeze the tank back down to the concrete.
I don't know how good that would be for the tank. I wonder if it would be better to leave it and just caulk around the base to keep water out. I certainly don't want to crack the bottom of the tank and end up with a leak.
Any thoughts on a repair?
Regards
StoneCold
RE: API 650 Tank with a Rolled Bottom Ring
RE: API 650 Tank with a Rolled Bottom Ring
pressure will try to round the floor of the tank which would
cause the edges to lift, You can see the anchor bolt chair ass mentioned above. All our SS tanks have the T-Joint on
the floor plate which extends 3-4" from the wall, no angle at
the bottom. One of the names for the floor plate that is outside the bottom ring is d compression ring even though it is part of the floor.
htt
This tank is on grillege and has many bolts on th cover plate insted of a few big ones.
RE: API 650 Tank with a Rolled Bottom Ring
Off the top of my head, a 12-ft tank needs substantial anchorage for 2.5 psig internal pressure
RE: API 650 Tank with a Rolled Bottom Ring
Either way it is kind of difficult to fix now.
Regards
StoneCold
RE: API 650 Tank with a Rolled Bottom Ring
I dare to say that the tank has beee overpressurize (gas o overfilled ) due to a low diameter averflow ,or inerte gas pressurized
The tank try to get the form of a barrel and the bottom goes up in order to get the spherical form.
so loose all bolt.
Youcan check it if you take the isolation of, an review the operating conditions
Make new chemical anchor in betwwen the old bolts
I hope you can repair it
Luis