What Is a V-Stack Seal Assembly?

A V-Stack Seal Assembly—often referred to as a seal stack or V-packing stack—is a combination of multiple sealing elements arranged in a stacked configuration. Each element features a chevron-shaped profile, allowing the stack to energize under pressure and create a reliable, long-lasting seal. Because the individual rings flex and adapt to pressure changes, a V-stack provides excellent sealing performance in demanding oil and gas environments.

How Does a V-Stack Seal Work?

The sealing principle is based on pressure-activated expansion.

When well pressure or hydraulic pressure is applied, each V-ring in the stack flares outward, pressing firmly against the metal housing. This creates a tight seal in both static and dynamic conditions. The stack is typically composed of:

• Female adapters – providing structural support
• Multiple V-rings – the primary sealing elements
• Male adapters – helping distribute load and stabilize the stack

This arrangement ensures the assembly can handle high pressures, large extrusion gaps, and significant mechanical movement.

Where Are V-Stack Seal Assemblies Used in Oil and Gas?

V-stack seals are widely used in various oilfield tools and surface equipment. Typical applications include:

• Wellhead and Christmas tree components
• Packers and downhole tools
• Hydraulic actuators and BOP equipment
• High-pressure service valves

Because the stack design tolerates wear, misalignment, and pressure cycling, it is ideal for the harsh and unpredictable conditions found in drilling and production environments.

Why Choose a V-Stack Seal Assembly?

A V-stack assembly offers multiple advantages:

• 1. Very robust seal
• 2. Multiple sealing lips for positive seal
• 3. Easy replacement in the field with split rings
• 4. Extensive range of sizes
• 5. Can be used with poor counter surfaces 
• 6. Operating temperatures of -49°F to +500°F / -45°C to +260°C depending on the elastomer
• 7. Compatible with virtually all media
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• The seal stack's material could be PEEK and modified PTFE, It has good elasticity, sealing efficiency and extrusion resistance.

For equipment that must remain secure under fluctuating pressures—such as wellhead bodies, actuating systems, and packer tools—V-stack seals deliver consistent reliability.

A V-Stack Seal Assembly is engineered to provide a stable, pressure-activated seal in demanding oil and gas applications. By combining multiple chevron-shaped rings into a single stack, it offers durability, adaptability, and strong extrusion resistance, making it a preferred sealing solution in high-pressure wellhead and downhole environments.