Back-Up Rings
Back-Up Rings
A back-up ring is a mechanical component used in conjunction with seals, such as O-rings or rod seals, to enhance their performance and prevent extrusion under high pressure conditions. These rings are typically made from durable materials like PTFE (polytetrafluoroethylene), nylon, or other thermoplastic materials.
Key Functions and Benefits
Extrusion Prevention
Back-up rings support the seal and prevent it from extruding into the gap between the mating hardware parts, which can occur under high pressure. Extrusion can lead to seal failure, so back-up rings are crucial in maintaining seal integrity.
Pressure Enhancement
By preventing extrusion, back-up rings allow seals to withstand higher pressures than they could on their own, extending the operating pressure range of the seal.
Improved Seal Life
The use of back-up rings can significantly increase the lifespan of seals by reducing wear and tear. This is because they minimize the deformation and damage that seals might otherwise experience under pressure.
Key Characteristics
Material
PTFE (Polytetrafluoroethylene): Offers excellent chemical resistance, low friction, and wide temperature range compatibility.
Nylon: Provides good mechanical strength and wear resistance.
Other Thermoplastics: Depending on specific application requirements, other thermoplastics can be used for their unique properties.
Design
Solid Rings: Continuous rings that provide robust support for seals.
Split Rings: Easier to install in grooves and can be used in applications where continuous rings are difficult to fit.
Spiral-Wound Rings: Provide flexibility and are easier to install in confined spaces.
Compatibility
Back-up rings are designed to be compatible with various types of seals and can be used in a wide range of applications, including those involving aggressive chemicals and extreme temperatures.
When To Choose A Custom Seal
Custom-designed sealing solutions play a pivotal role in addressing the diverse and intricate sealing challenges across various industries. As an expert, you understand that off-the-shelf sealing products often fail to meet the unique demands posed by specific applications, operating conditions, and...
Products & Resources
R. E. Purvis & Associates, Inc. is a recognized Sealing Technology Center for Parker's EPS (Engineered Polymer Systems) Division. Parker's EPS Division is a premier manufacturer of hydraulic seals which offers many geometric sealing profiles along with a vast selection of material options.
