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{{Other uses, Obturator (disambiguation){{!Obturator
An obturating ring is a ring of relatively soft material designed to
Obturating rings are common in artillery, where the hard steel casing of the shell is too hard to practically deform to provide a tight seal for the propellant gases. An obturating ring or
81 mm mortar shell information
showing the obturating ring Artillery components
obturate
In the field of firearms and airguns, obturation denotes necessary barrel blockage or fit by a deformed soft projectile (obturation in general is closing up an opening). A bullet or pellet, made of soft material and often with a concave base, ...
under pressure to form a seal. Obturating rings are often found in artillery
Artillery is a class of heavy military ranged weapons that launch munitions far beyond the range and power of infantry firearms. Early artillery development focused on the ability to breach defensive walls and fortifications during siege ...
and other ballistics applications, and similar devices are also used in other applications such as plumbing
Plumbing is any system that conveys fluids for a wide range of applications. Plumbing uses pipes, valves, plumbing fixtures, tanks, and other apparatuses to convey fluids. Heating and cooling (HVAC), waste removal, and potable water deliv ...
, like the ''olive'' in a compression fitting
A compression fitting is a fitting used in plumbing and electrical conduit systems to join two tubes or thin-walled pipes together. In instances where two pipes made of dissimilar materials are to be joined (most commonly PVC and copper), the ...
. The term "O-ring
An O-ring, also known as a packing or a toric joint, is a mechanical gasket in the shape of a torus; it is a loop of elastomer with a round cross-section, designed to be seated in a groove and compressed during assembly between two or more par ...
" is sometimes used to describe this kind of pressure seal.
Ballistics uses
Obturating rings are common in artillery, where the hard steel casing of the shell is too hard to practically deform to provide a tight seal for the propellant gases. An obturating ring or driving band Russian 122 mm shrapnel shell, which has been fired, showing rifling marks on the copper driving band around its base and the steel bourrelet nearer the front
A driving band or rotating band is a band of soft metal near the base of an artillery ...
made of a softer material is the typical solution. Mortar bombs also use obturating rings to provide a seal around the projectile. Recoilless rifles and some artillery use rings with a reverse impression of the rifling cut in them for a tighter seal even at very low pressures.
Some artillery shells use an obturating ring at the rear of the shell to provide a tight seal for the breech. This allows a mostly caseless ammunition without the sealing issues generally encountered in such ammunition. The obturating ring provides the sealing that would normally be provided by a cartridge case
A cartridge or a round is a type of pre-assembled firearm ammunition packaging a projectile ( bullet, shot, or slug), a propellant substance (usually either smokeless powder or black powder) and an ignition device ( primer) within a metal ...
.
See also
*Broadwell ring The Broadwell ring is a small obturating ring used in 1860s and 1870s rifled breech loaders in Continental Europe to ensure obturation
In the field of firearms and airguns, obturation denotes necessary barrel blockage or fit by a deformed soft ...
* Charles Ragon de Bange
References
81 mm mortar shell information
showing the obturating ring Artillery components