For applications with special sealing and reliability requirements, JST has developed a chevron packing set that combines its proven spring energized seal design technology with PTFE-based materials, and other high-performance polymer plastics.

A typical PTFE chevron stack consists of a radial spring energized seal, several V-rings and an anti-extrusion ring.

The spring energized seal is the main sealing element. The pressurised spring energized seal automatically energizes a series of V-shaped segments stacked behind it, pushing the lips outwards. The multiple sealing areas generated this way reduce the risk of leakage.

Each V-ring responds to pressure shocks and even small pressure changes by providing an immediate sealing effect.

The anti-extrusion ring prevents the softer PTFE elements from being extruded into the downstream hardware gap.

Advantages compared to conventional elastomer-based chevron stacks:

• Advantages of PTFE over elastomer materials.
• No special tools required.
• Quick design and short manufacturing time.
• Simplified hardware and groove assembly as no need for mechanical loading mechanism.

The chevron stack sealing elements are made of pressure-resistant and wear-resistant PTFE compounds. The anti-extrusion ring is usually made of PEEK.

To meet the sealing needs of the energy, oil and gas markets, JST offers a range of NORSOK and NACE approved materials. A dedicated list is available upon request.