Burst disk

Revision as of 18:13, 1 February 2006 by 71.136.47.52 (talk)

A burst disk ruptures when the pressure gets to a certain point, allowing the gas to propel the projectile down the barrel. Due to this method of "opening", they have the fastest opening time of any valve in existence. They are nearly always used for hybrids, and occasionaly as the main valve in a pneumatic cannon.

They are a very close rival to a ball valve in cost, at roughly 13$ for a 2" union in sch 40 PVC. More expensive (but conveinent) devices exist, such as cam lever couplings. To use, solvent weld your chamber to one half of your union or cam coupling. One then 'loads' the valve by putting a layer of some weak material (such as multiple layers of aluminum foil, or a piece of a beverage container) in between the 2 halves of the union or coupling. The union or cam coupling is then tightened down, locking the disk of burst disk material in place.

In a hybrid cannon, burst disks fail when the pressure builds due to the combusting gasses. Prior to this, chamber was containing the flammable gasses at a relatively low pressure. They are also sometimes used on combustion cannons - for their noisemaking capabilities, and/or their (debated) performance improvement.

In a pneumatic cannon, they can be used in the same way, simply pointing the cannon in the correct direction and filling it until it fires. However, many opt to use another system because of the inherent safety issues with this. Such systems include puncturing it with a pointy object (such as a nail) attaced to the end of the projectile, melting it with an electrically heated wire, and a pneumatically triggered burst disk system using dual burst disks.