Use of air bags to lift horiz. full tank.
Use of air bags to lift horiz. full tank.
(OP)
Can anyone offer any advice on the use of air bags to lift a full, horizontal pressure vessel(approx 7ft dia, 26 ft lg) in order to install a load cell weighing system? The vessel WITH liquid contents weighs approx 60K lbs.. I've been told using the air bag approach to lifting the full tank is a safe and reliable method of lifting the tank 12" or so. In the past, we've always emptied the tanks and used a crane to lift the tank by its lifting lugs. Using the air bags to lift the full tank would certainly be a more economical solution. Although I'm trying to keep an open mind, I have doubts on the use of air bags in lifting large, live loads.





RE: Use of air bags to lift horiz. full tank.
What you need to check first is where you will put the bags so as to transfer the loads correctly without damaging the tank or sunking into the soil. Normally you would only be allowed to use the saddles, right where you need to install the cells.
Your figure of 12", though feasible, seems a bit high for this application. You should check with actual products the lifting capacity wrt lifting height.
Also at that height and mass you should be concerned about correctly laterally restraining any movement of the tank when lifted. Also consider, supposing you'll use four bags, that one or two of them might lose pressure accidentally, and your load must remain stable and not be damaged under that condition.
prex
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RE: Use of air bags to lift horiz. full tank.
Is the tank currently supported by two saddles ?
If so, then it would be prudent to lift the tank in two places (nearby the saddles).
With a two(or more) point lifting scheme, there is a possibility that the tank will become unstable and roll.
The fluid contained within the tank could shift....
Hire a crane.....
RE: Use of air bags to lift horiz. full tank.
One more observation. Tanks have been around for a long time. Air bags have been around for a long time. However, overwhelmingly, generations of contractors have shown a preference for cranes to safely lift tanks. I've known contractors to be a pretty sharp bunch. There must be good reasons why they still use cranes instead of air bags. BTW, I'm not a crane contractor. Just someone trying to find the best way to lift full, horizontal tanks a few inches.
Thanks again,
Dean Quest
RE: Use of air bags to lift horiz. full tank.
Maybe Enerpac (some of the above still need to be addressed - though they have standard solutions which are used all the time).
Regards,
Lyle
RE: Use of air bags to lift horiz. full tank.
If I had to move a tank "a few inches", I'd certainly look at doing it with air bags. Cranes do an amazingly lousy job of moving a heavy load a short distance. With the air bags you never have the load suspended in air and subject to wind currents. Write a heavy-lift procedure with enough safety factor to account for the issues above (e.g., maybe use 50% more bags than necessary, manifold the air supply so all get air at the same time, specify a slow rate of pressurization, etc).
David
RE: Use of air bags to lift horiz. full tank.
What will prevent the liquid from shofting/sloshing form one end of the tank to the other ?
This will occur if there is the slightest difference in the rate of filling of the air bags or if one saddle support becomes caught in any way
RE: Use of air bags to lift horiz. full tank.
Not a bad idea. Good objections and recommendations have been made above.
Using airbags to lift a small (completely full and well-capped) tank like this?
Might work. I would not do it, but it might work.
Using airbags to lift a small (partially full) tank like this?
Priceless.
No, literally, priceless. You'll never stop paying after the load shifts off "perfectly flat" by even a little bit.