Self-Supported Cone Roof
Self-Supported Cone Roof
(OP)
Hi,
I have a client that is requesting to fill a 2" in 12" self-supported cone roof up to the very top (apex) of the roof with liquid. I know this raises alarms in regards to venting, etc...
What my question is - how does the liquid apply pressure on the underside of the roof? I would imagine it has a horizontal hydrostatic pressure. But does it also have a vertical uplift (buoyancy if you will) equal to the difference between the very top point of the tank and the point in question multiplied by the density of the liquid?
This is for a wine tank (designed (kind of) to API 650). According to the customer, every wine tank is filled this way to the very top of the roof (to avoid any air being trapped on top of the wine).
Thanks!
I have a client that is requesting to fill a 2" in 12" self-supported cone roof up to the very top (apex) of the roof with liquid. I know this raises alarms in regards to venting, etc...
What my question is - how does the liquid apply pressure on the underside of the roof? I would imagine it has a horizontal hydrostatic pressure. But does it also have a vertical uplift (buoyancy if you will) equal to the difference between the very top point of the tank and the point in question multiplied by the density of the liquid?
This is for a wine tank (designed (kind of) to API 650). According to the customer, every wine tank is filled this way to the very top of the roof (to avoid any air being trapped on top of the wine).
Thanks!





RE: Self-Supported Cone Roof
You'd want some type of relief valve so that thermal expansion/contraction and similar effects didn't overstress anything.
RE: Self-Supported Cone Roof
The only upward pressure, as it would be at atmospheric initially, would be any internal pressure generated by the fermentation process. Check with the client for this, but it could be minimized with a pressure relief valve as previously mentioned.
Bottom line is I do not think there will be much uplift on the top of the tank unless the relief valve fails.
Mike McCann
MMC Engineering
Motto: KISS
Motivation: Don't ask
RE: Self-Supported Cone Roof
I'm just trying to wrap my head around whether I should design the roof plates/rafters for a vertical (upward) load from the hydrostatic head.
Thanks again!
RE: Self-Supported Cone Roof
SO, I would check with the valve supplier, or the owner, to see at what atmospheric overpressure the relief valve is supposed to trip, and design the roof structure for at least 10% more to be sure.
Mike McCann
MMC Engineering
Motto: KISS
Motivation: Don't ask
RE: Self-Supported Cone Roof
RE: Self-Supported Cone Roof
RE: Self-Supported Cone Roof
A cone roof is a very inefficent configuration for this kind of loading.
A domed roof or some kind of umbrella roof is a better choice...perhaps an elipsiodal configuration
If you client starts crying and complaining about not being able to use this top volume on his cone topped tank, tell him he should have considered this when the tank was specified/purchased.
Clients cant always get what they want.....
RE: Self-Supported Cone Roof
I don't understand of what use a "fully filled" cone roof tank would be in the wine industry.
You can't fill it anymore without tank explosion, you cant empty it without extreme venting provisons.....nobody else configures tankage in this way
Oh,......and ask the client if he has ever heard of the widespread industry practice of using nitrogen blankets on wine tanks.
h
RE: Self-Supported Cone Roof
RE: Self-Supported Cone Roof
RE: Self-Supported Cone Roof
Hydrostatic pressure.
RE: Self-Supported Cone Roof
You will see uplift on the tank head due to the static head of the liquid pushing up on the head. No different than if internal pressure is pushing up on the head.
RE: Self-Supported Cone Roof
RE: Self-Supported Cone Roof