Calculation of Collapse Pressure for Perforated Pipes

[kvbalug]

Hi all

Can you please guide me on how to calculate the collapse pressure of perforated Pipes.

My case is to make a 2mm thick Pipe (1500 mm long) to be used as a filter element with perforations. The wire meshes shall be wound around the perforated pipe.

Design pressure - 5 kg/sqcm(g), which shall be the maximum differential pressure across the Perforated pipe
Required No. of holes on Pipe = 1250
Hole diameter = 8 mm
Hole pitch = 13 mm, triangular pitch

Are there ready references ??

Thanks in advance

 

[kvbalug]

Additional data (forgot to mention)

Flow is from outside to inside (external pressure design case of 5 kg/sqcm)
Material of construction of Pipe - SA240-304

 

[LittleInch]

What's the Od of your pipe?

Is 5 bar differential the maximum pressure outside, assuming zero inside and a fully blocked filter?

Is a fully blocked filter realistic?

The difficulty of this approach is why you normally go inside to out, plus it makes the capture of dirt a lot easier.

However assuming you're stuck with your design and flow and not bothered about debris, I think you will either have to model this in FEA or you may just make one and test it. Try a cylinder 1mm thick or 0.5mm thick and see if it holds up.

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

 

[bimr]

You also seem to have left out the diameter.

Never have run across a method to calculate the collapse pressure of drilled pipe.

Some observations:
[ol 1]
[li]The movement of the media may have more force than the differential pressure. If the media in the tank shifts, it may break the pipe.[/li]
[li]Usually people use larger holes in the pipe and rely on the wire mesh to do the filtering.[/li]
[li]You can buy commercial products such as well screen. Collapse pressures are in the brochure.

http://www.johnsonscreens.com/sites...l Screens and Accessories - North America.pdf

[/li]
/ol]

 

[georgeverghese]

What about the mesh (or is this some some kind of fine wire screen?) - would this not collapse before the pipe does at 5kg/cm2(g)?

 

[prex]

I would start by using an equivalent elastic modulus reduced in proportion to [tt](p-d)/p[/tt]=5/13 in your case.
A justification to this is that a tube buckles by forming an oval (or a higher order waved shape), and longitudinal weak lines passing through the ligaments will be the source for bending to the collapsed shape.

prex
[URL unfurl="true"]http://www.xcalcs.com[/url] : Online engineering calculations
[URL unfurl="true"]http://www.megamag.it[/url] : Magnetic brakes and launchers for fun rides
[URL unfurl="true"]http://www.levitans.com[/url] : Air bearing pads

 

[BigInch]

I'd test it in a testing MACHINE.