Solid Spiral Multiturn Sealing PTFE Backup O Ring As568 Standard

PTFE Backup Rings — Groove Width and Seal Support Clearance

A PTFE backup ring supports an O-ring at the extrusion clearance. Match its ID, OD and axial thickness to the complete groove, including the space required by the O-ring. Specify static or dynamic service before dimensional review.

Define operating clearance, temperature, fluid and pressure peaks together with the PTFE grade. Ring dimensions and material data must be reviewed as part of the assembly; PTFE does not establish universal hydraulic-fluid compatibility or an independent pressure rating.

PTFE Material and Dimensional Requirements
Virgin PTFE hardness reference: 55 Shore D; confirm grade, test method and acceptance range.

Solid, scarf-cut and spiral rings are separate constructions. Specify the ordered form and its section dimensions, then confirm installation access and groove fit.

Material range:

Virgin PTFE: review compression, creep and dimensional stability at the specified temperature and load.

Filled PTFE: specify filler type and content; review fluid compatibility, deformation and mating-surface requirements.

Provide the AS568 O-ring dash number and groove section drawing with ring dimensions, tolerances, construction and quantity.

Record groove width, depth and the operating extrusion gap. Include dimensional changes under pressure and temperature when defining the available space for seal and backup support.

If extrusion damage is present, inspect the gland and record pressure direction, gap and O-ring condition. A replacement ring should be checked against mating dimensions rather than only a distorted sample.

Review O-ring squeeze and groove occupancy together with backup ring thickness. Specify surface finish, assembly access and movement; a ring must fit the intended design without assuming that additional thickness improves sealing.

For a defined pressure direction, support the O-ring on its low-pressure side. Reversing pressure may require support on both sides; confirm the combined groove width and orientation on the drawing.

NBR or FKM 90-durometer rubber backup rings are separate alternatives. Confirm compound and hardness scale; PTFE hardness uses its own specified test scale.

Contoured rings require an approved section drawing and material designation.

Related Rubber and Oilfield Components

Rubber O rings:

1) Standard O-Rings

Sizes: AS568 dash sizes or metric dimensions with specified tolerances.

Materials: NBR, silicone, FKM, HNBR or EPDM by specification; food-contact requirements need compound documentation.

Color: Black, Brown, or custom color.

2) Custom rubber o rings, X rings, or kinds of seals and washers&gaskets.

Custom parts are quoted against an approved drawing or sample with mating dimensions.

Specify shape, color and hardness requirements on the drawing.

Hammer union seals

Rubber union seals with or without brass or stainless-steel backup rings; fit by assembly specification.

Available Material: NBR, FKM, HNBR.

Nominal union sizes: 1, 1.5, 2, 3 and 4 inches; seal dimensions by assembly drawing.

Plug seals

Available Material: NBR, FKM, HNBR ect.

Nominal size references: 1, 2 or 3 inches; plug seal fit by assembly drawing.

Dust Seals or Swivel Dust Seals

Oil saver rubbers

Pipe wipers

Swivel Ball Plugs

Thread Protectors

Related product photographs for reference; confirm the ordered ring by drawing:

Additional related product photographs:

For a groove-fit enquiry, send the section drawing, O-ring dash size and backup ring ID, OD and thickness. Include tolerances, maximum operating gap, pressure direction, PTFE grade, fluid, temperature and quantity.