Floating Suction Design

[Leinster]

I need to design a floating suction and want to establish how buoyant the float should be. We are designing for a tank of 5.9m Dia x 7.5m High with only one single swivel elbow. This will mean that the when the tank is filled to the top the float will be submerged so I do not want to make the float lighter than it should be.

As the float is not required to lift the entire weight of the pipe I would like to know what percentage of the weight it should be designed to lift. Either a rule of thumb or pointers into design calculations would be appreciated.

 

[IFRs]

If the pipe is supported on both ends, then both ends support half the load in all positions. Do a moment balance about the swingjoint. See attached for an example.

 

[JStephen]

I don't know that there's a good substitute for just going into detail with the things. I've use a spreadsheet to calculate center of mass and center of volume, which lets you calculate buoyant uplift. For a partially-submerged float, this involves some iteration to find the product depth corrosponding to a particular suction angle.