Why the groove makes all the difference

For mechanical seals, the groove defines stability and control.

In coaxial separation seals, one detail makes all the difference: the groove. It's the quiet architect of stability, leakage control and resilience when conditions get challenging. The industry standard is the continuous groove, a full circumferential channel, often featuring at the inner and outer diameters to generate some hydrodynamic lift. It works, but at its heart, it behaves much like a hydrostatic seal. That means it can hold a film, but the film itself is soft, lacking stiffness when the mechanical seal is exposed to upset conditions.

The TriHex groove takes a different approach. Instead of a continuous channel, it uses a discontinuous pattern that acts both hydrostatically and hydrodynamically. The result is a fluid film that doesn't just separate the faces but actively resists collapse under upset conditions.

Why stiffness matters

In normal operation, both continuous and discontinuous grooves can maintain a gas film and control leakage. The difference shows up in the moments that matter most: upset conditions.

• Loss of separation gas: With traditional grooves, the fluid film softens quickly, leaving the seal vulnerable to contact.
• Primary dry gas seal failure: In this mode, the full process pressure suddenly acts on the inner diameter of the separation seal. In traditional designs, this high load can drive the seal faces into contact. With the TriHex, the added stiffness resists that collapse, keeping the faces apart.

What makes the TriHex different is its self-correcting nature. As the film gap narrows, the discontinuous groove generates a sharp increase in opening force — the harder it's pressed, the harder it pushes back. This automatic balancing response prevents contact and ensures stability, even at low speeds or during upset conditions.

Force balance across the range

The TriHex design has another advantage: its force balance keeps the seal faces stable across the full speed range, from standstill up to 120 m/s, and under all typical separation gas pressures. This balance ensures healthy leakages at both the outer and inner diameters, avoiding any risk of face contact. In addition, the well-designed groove minimises heat generation and maintains controlled temperatures during operation.

The separation gas feed is distributed evenly, supporting consistent performance across all conditions.

The outcome?

• Competitive leakage aligned with industry expectations
• Controlled temperatures throughout the operating envelope
• Predictable behaviour even as supply conditions vary

Why the TriHex groove stands out

What does all this mean in practice? For customers, it comes down to confidence and knowing the separation seal will behave the way you need it to, whether everything is running smoothly, or the system is under stress. Here's how the TriHex makes that happen:

• Resilient – It keeps working even if the separation gas is lost or the primary dry gas seal fails.
• Reliable – Its stiff fluid film doesn't give way under pressure, so the faces stay stable when conditions get tough.
• Consistent – Leakage and temperatures stay balanced across the whole speed range and a wide span of supply pressures.
• Scalable – The design holds up whether the seal is small or large in diameter.
• Adaptable – It can be tuned to take on extreme applications, like very high-speed service.

In short, the TriHex doesn't just survive upset conditions — it thrives in them.

A groove designed for the real world

The TriHex groove isn't about chasing novelty, it's about solving the real challenges that coaxial separation seals face in service. By combining hydrostatic and hydrodynamic behaviour in one design, it delivers a fluid film that is not only strong, but smart — able to adapt, correct and protect under the very conditions where reliability matters most.