Drain Dry System for conical floor tank.
Drain Dry System for conical floor tank.
(OP)
Has anyone had experience with a "drain dry" system for a conical floor storage tank. I believe the idea is to slope the tank floor to the center and run an outlet pipe from the side of a sump which would be installed at the low point of the cone, thru the tank pad (sand & gravel construction) and terminate in a 150# connection flange.
The tanks are 191' Dia. so the piping would have to run approx. 95' horizontally thru the pad. My concerns are:
1. Centre column support for roof rafters would be located inside the sump. (or sump c/b located off center to avoid this.
2. Loadings on the horizontal, buried pipe running thru the tank pad.
3. onstruction of sloped gravel/sand tank pad.
4. Etc., etc.
I checked API 620 & this is not addressed there.
API 650 Appendix "O" - covers under-bottom connections for flat bottom tanks so I'm thinking I could use this as a guide. But I'd rather borrow on others' experience if you've run across this before.
The tanks are 191' Dia. so the piping would have to run approx. 95' horizontally thru the pad. My concerns are:
1. Centre column support for roof rafters would be located inside the sump. (or sump c/b located off center to avoid this.
2. Loadings on the horizontal, buried pipe running thru the tank pad.
3. onstruction of sloped gravel/sand tank pad.
4. Etc., etc.
I checked API 620 & this is not addressed there.
API 650 Appendix "O" - covers under-bottom connections for flat bottom tanks so I'm thinking I could use this as a guide. But I'd rather borrow on others' experience if you've run across this before.





RE: Drain Dry System for conical floor tank.
1. You could bridge the sump for your center column support, or you could consider a geodesic dome roof. If you are at a coastal location the geo-dome may be a bad idea though.
2. The under-bottom pipe should be capable of handling the overburden load, however you could consider an underbottom trench constructed of heavy plate to house the piping. I have seen these used with ringwall foundations mostly.
RE: Drain Dry System for conical floor tank.
RE: Drain Dry System for conical floor tank.
RE: Drain Dry System for conical floor tank.
Joe Tank
RE: Drain Dry System for conical floor tank.
The drainage scheme that you are describing is commonly called "cone-down" configuration. Both the "cone-up" and "cone-down" configurations are described in the book by Phillip Myers "Aboveground Storage Tanks".
Most evidence is anecdotal, but it is my understanding that "cone-up" tanks are preferred because of resistance to corrosion (distributed in the edge, as opposed to concentrated in the tank center) and resistance to leakage, if the tank settles in the ground.
My opinion only...
Anybody else have experiences or references to share ?
-MJC