burst disc
Posted: Thu Jan 29, 2009 11:44 pm
Hey, I was wondering if anyone knew if 1 layer of aluminum foil bursts in a 1/2 inch PVC union at 40-60PSI?
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Posted: Thu Jan 29, 2009 11:55 pm
Isn't 1 layer of foil 10-20 psi?, But that said, the smaller the diameter, the more each layer will hold. Can't give you an accurate enough answer.
Posted: Fri Jan 30, 2009 12:51 am
Well my one inch bursts at 20 psi and my 1.5 inch bursts at 15 psi. For every half inch you go up it decreases pressure by 5 so maybe 25 psi. I doont know you would have to try.
Posted: Fri Jan 30, 2009 7:54 am
We all have different kinds of foil etc. The best way is to measure it yourself, really.
Posted: Fri Jan 30, 2009 9:53 am
Does anyone know of a way to calculate the burst pressure using the tensile strength, thickness, and area of the disk?
I know there's Barlow's formula for pipes but is there a variation for just a flat area?
I know there's Barlow's formula for pipes but is there a variation for just a flat area?
Posted: Fri Jan 30, 2009 11:17 am
I'm pretty sure theres a page on the spudfiles wiki about burst pressures of different materials on differend diameter pipes, there is not everything, but there could be something close to what you are looking for...
EDIT heres the page, http://www.spudfiles.com/spud_wiki/inde ... k_material
It does not have exactly what you are looking for, but then again, you could always test it yourself
EDIT heres the page, http://www.spudfiles.com/spud_wiki/inde ... k_material
It does not have exactly what you are looking for, but then again, you could always test it yourself
Posted: Fri Jan 30, 2009 10:06 pm
Well i think this would depend on the brand. But in my 3/4in. union one layer burst at 25psi, i use reynolds extra strength. 
Posted: Fri Jan 30, 2009 10:41 pm
Some info on calculations at the bottom of this thread.
Posted: Fri Jan 30, 2009 10:47 pm
Anyone planning to build a burst disk system for any type cannon should plan on a fairly extensive testing session with their chamber and a reasonably good pressure gauge and with compressed air, test break points layer by layer. Plan on several "shots" and keep ear protection handy. It isn't difficult and will give you confidence in your system.
The burst material and the area of the burst opening will make the burst point different on each configuration.
Note that this test represents a relatively slow rise in pressure. With small millisecond combustion times, the pressure peak may need to be somewhat higher than the test reading to actually break the disk, depending on your disk material. For example, a typical 90-100 psi peak combustion pressure may have trouble breaking an 80 psi "slow measured" disk.
The burst material and the area of the burst opening will make the burst point different on each configuration.
Note that this test represents a relatively slow rise in pressure. With small millisecond combustion times, the pressure peak may need to be somewhat higher than the test reading to actually break the disk, depending on your disk material. For example, a typical 90-100 psi peak combustion pressure may have trouble breaking an 80 psi "slow measured" disk.