PTFE Backup Anti Extrusion Ring For Static Sealing

PTFE Backup Rings — Solid, Scarf-Cut and Spiral Construction Selection

PTFE backup rings support an O-ring adjacent to the extrusion gap. Define the gland dimensions and installation access before selecting solid, scarf-cut or spiral construction for the specified static or dynamic assembly.

Ring construction and PTFE grade must be selected together with fluid, temperature, pressure peaks and operating clearance. Compatibility and extrusion resistance depend on the complete gland; the ring has no independent assembly pressure rating.

Construction and PTFE Grade
Virgin PTFE hardness reference: 55 Shore D; confirm grade, test method and acceptance limits.

Solid rings are uncut and need a suitable assembly route. Scarf-cut rings have a specified angled joint, while spiral rings use a multiturn form. Confirm the ordered joint geometry, thickness and installation method rather than substituting by nominal diameter.

Material range:

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

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

Send the O-ring dash size and groove drawing with ring ID, OD, thickness, construction and tolerances for quotation.

Include groove width and the space occupied by the O-ring and support ring. Define pressure direction and the maximum extrusion clearance under load.

When replacing a damaged ring, identify its original construction and record the gland condition. A worn or distorted sample should be compared with mating dimensions before establishing replacement tolerances.

For cut or spiral rings, specify joint or turn geometry on the drawing and review assembly instructions. Confirm fit and condition after installation; ring construction does not correct an unsuitable gland clearance.

Support the O-ring on the low-pressure side for the specified pressure direction. For reversing pressure, review support on both sides and confirm groove space in the assembly drawing.

NBR or FKM 90-durometer rubber backup rings are separate options requiring compound and hardness-scale confirmation. Rubber Shore A values do not describe PTFE hardness.

Contoured rings require a separate section drawing, construction and material specification.

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 part 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; identify the ordered ring by drawing:

Additional related product photographs:

For a construction-specific backup ring enquiry, identify solid, scarf-cut or spiral form and send the gland drawing. Include PTFE grade, ring dimensions, assembly access, pressure direction, fluid, temperature and quantity.