Greene, Tweed’s AGT® ring, a double-acting rod or piston seal, provides the quality and reliability the Aerospace industry requires. The AGT ring offers an outstanding combination of easy installation, low leakage and long service life for exceptional performance in many static and dynamic sealing applications.
Constructed of superior elastomers and thermoplastics to withstand harsh fluid and service conditions, the AGT ring resists O-ring roll and spiral failure.
For pressures up to 4,000 psi (276 bar), we recommend standard diametrical clearances per MIL-G-5514/AS4716 and AS4832, providing proper gland lengths and materials are selected.
Pressure Responsive Anti-Extrusion Rings
The AGT ring will completely bridge any extrusion gap by hydromechanically “lifting” the anti-extrusion rings in phase with the pressurization of the elastomeric flange supporting the rings. Materials used include high shear and creep resistant fluoropolymers and thermoplastics rated to extreme pressures and clearance gaps typical of landing/recoil systems, pressure vessels and applications with wear rings or independent running bearings. These anti-extrusion materials can be tailored to any given pressure, temperature and clearance gap condition. O-ring anti-extrusion rings, on the other hand, are dependent upon the deformation characteristics of the selected material to radially bridge the clearance gap.
“Staged” and “Split-Lock” Anti-Extrusion Ring Set
It is possible, within wide base gland arrangements, to “stage” two
anti-extrusion ring materials on each side of the elastomeric sealing
stem in order to accommodate high acceleration and pressure rates.
The “softer” in-board PTFE material will protect the elastomer from
abrasion and nibbling while the higher modulus out-board antiextrusion
ring performs the required anti-extrusion function.
Staged rings can also be provided with our patented “split-lock” design. Each independent scarf cut ring is interlocked along the radial face simulating the ease of assembly of a one-piece continuous or endless anti-extrusion.
The ring halves are dovetailed together, allowing the ring set to expand—“open”—for easier assembly than typical piston-type glands. For rod-type assemblies the gland must be open ended, permitting the locked ring sets to be placed down in the gland. This produces a stable ring within the gland that will not dislodge and become sheared during a blind assembly or with rotational
motion typical of threaded end caps. Split-lock rings are ideal for field repair of landing gear shock struts.
Note: For rod-type assemblies the gland must be open ended, permitting the locked ring sets to be placed down in the gland.
The Greene, Tweed HPGT is a bidirectional rod or piston back-up ring designed for MIL-G-5514/AS4716 grooves. The HPGT uses bias cuts instead of scarf cuts in the high-modulus, anti-extrusion rings required for this level of maximum service. This bias cut configuration prevents extrusion of the elastomeric flange via the scarf cut.
Unidirectional (AGTL™) Option
For installations where pressure is unidirectional, the AGTL™ ring offers a compact space saving design within the “zero anti-extrusion” and “one anti-extrusion” length glands if required. The “L” Ring sealing element with integral pressure responsive anti-extrusion ring provides an optimum axial seal footprint with a thicker antiextrusion ring suitable for larger clearance gaps and higher pressures.
The part numbering system requires the use of the material designator tables found in the next column. For nonstandard designs contact GT engineering.
Contact your local Greene, Tweed representative for specific recommendations to suit higher performance requirements.