PTFE Back-up Rings have no intended sealing function. Instead, as their name indicates, they are protective and supporting elements made from extrusion-resistant materials which generally have a rectangular cross section. They are installed in a groove together with an elastomeric sealing element preferably with a corresponding O—Ring in static applications. Due to the tight fit of the Back-up Ring in the housing, they prevent extrusion of the pressurised elastomeric sealing element into the sealing gap.

Advantages

- Use of O—Rings in high pressure applications

- Use of O—Ring materials with a low hardness

- Compensation of radial sealing gaps

- Use for internal and external sealing applications

- Reciprocating and rotating movements possible

- Compensation for large temperature fluctuations

- Static and dynamic applications

Back-up Ring types, uncut

Type BV

- Rectangular cross section

- Material PTFE

- Static and dynamic use

- Reciprocating and rotating movements possible

Type BB

- Concave cross section

- Materials: NBR, FKM

- The large contact surface protects the O—Ring against

deformation in case of high pulsating pressure

- Dimensional stability of the O—Ring improves the sealing

force and increases the service life

- Preferably for static use

- Reciprocating movements possible

Type BA

- Concave cross section

- Material: PTFE

- The large contact surface protects the O—Ring against

deformation in case of high pulsating pressure

- Dimensional stability of the O—Ring improves the sealing

force and increases the service life

- Static and dynamic use

- Reciprocating and rotating movements possible

Type BD

- Concave cross-section

- Material: PTFE

- Cut angle of 30° or 45°

- The large contact surface protects the O—Ring against

deformation in case of high pulsating pressure

- Dimensional stability of the O—Ring improves the sealing

force and increases the service life

- Static and dynamic use

- Reciprocating movements possible

- Preferred for installations in a closed groove where uncut

Back-up Rings are not suitable

Back-up Ring types, spiral

Type BP

- Rectangular cross section

- Material: PTFE

- Cut angle of 30° or 45°

- Consists as standard two spiral windings which are cut at

the ends at an angle

- Static and dynamic use

- For reciprocating movements only

- Preferred for installations in a closed groove where uncut

Back-up Ring are not suitable

- Compensation of large temperature changes and

tolerances without difficulties by a screw-like

elongation and contraction. Easy Installation in closed

grooves for external sealing applications

- The dimensions are different compared to standard Backup

Rings

Type BU

- Rectangular cross section

- Material: PTFE

- Static and dynamic use

- Reciprocating and rotating movements possible

Type BB

- Concave cross-section

- Materials: PTFE, NBR, FKM

- The large contact surface protects the O—Ring against

deformation in case of high pulsating pressure

- Dimensional stability of the O—Ring improves the sealing

force and increases the service life

- Static and dynamic use

- Reciprocating movements possible

Back-up Ring types, cut

Type BG

- Rectangular cross section

- Material: PTFE

- Cut angle of 30° or 45°

- Static and dynamic use

- Reciprocating and rotating movement possible

- Preferred for installations in closed grooves where uncut

Back-up Rings are not suitable

Type BC

- Concave cross-section

- Material: PTFE

- Cut angle of 30° or 45°

- The large contact surface protects the O—Ring against

deformation in case of high pulsating pressure

- Dimensional stability of the O—Ring improves the sealing

force and increases the service life

- Static and dynamic use

- Reciprocating movements possible

- Preferred for installations in a closed groove where uncut

Back-up Rings are not suitable

Type BP

- Rectangular cross section

- Material: PTFE

- Cut angle of 30° or 45°

- Consists as standard two spiral windings which are cut at

the ends at an angle

- Static and dynamic use

- For reciprocating movements only

- Preferred for installations in a closed groove where uncut

Back-up Rings are not suitable

- Compensation of large temperature changes and

tolerances without difficulties by a screw-like

elongation and contraction

External sealing (Bore)

Type BV

- Rectangular, uncut, PTFE

Type BH

- Rectangular, cut, PTFE

Type BD

- Concave, cut, PTFE

Type BP

- Spiral, PTFE

Type BB

- Concave, uncut, NBR + FKM

Type BA

- Concave, uncut, PTFE

Internal sealing (Rod)

Type BU

- Rectangular, uncut, PTFE

Type BG

- Rectangular, cut, PTFE

Type BC

- Concave, cut, PTFE

Type BP

- Spiral, PTFE

Type BB

-Concave, uncut, NBR + FKM + PTFE