What is a Combination Seal?

In over three decades working around sealing solutions, one recurring question keeps coming back from customers: Is there a seal that can survive in tight spaces, under pressure fluctuations, without wearing out too quickly?

The answer is not a single product, but rather a design approach. That is where the Combination Seal series comes into play.

What is a Combination Seal?

Instead of relying on one sealing element, a combination seal integrates two or more materials or geometries into one compact unit. Each part contributes something different: one layer might provide elasticity and tight fit, while another ensures low friction and durability.

A common example is in hydraulic cylinders. Relying solely on an O-ring or a lip seal will not last long under high loads. But pairing PTFE with an elastomer energizer creates a far more resilient solution. PTFE delivers wear resistance and low friction, while the elastomer ensures close contact with the groove. This hybrid design is why many in the industry simply call them “combination seals.”

Why Engineers Choose Them

The strength of combination seals is versatility.

· Materials: options range from NBR, FKM, and polyurethane to filled PTFE. The mix can be tailored to the operating environment—whether that means high temperatures, aggressive media, or abrasive conditions.

· Pressure handling: while standard hydraulic seals often top out at moderate loads, combination seals can comfortably work in systems reaching and exceeding 35 MPa.

· Compact design: when there is no extra room in the housing, the combined seal still delivers both sealing and guiding functions in one compact profile.

In short, these seals give designers breathing room: higher performance without demanding bigger housings.

Lessons From the Field

A good illustration came from a wind turbine main shaft project we handled a few years back. The customer had tried single-lip seals, but after only six months the seals wore out and leakage started. We re-engineered the sealing system with a polyurethane outer ring and an FKM O-ring energizer inside. The result? The lifetime doubled, and unplanned downtime was cut in half.

This is what convinces engineers and distributors alike: it is not about a catalogue part, but about matching the seal to the real environment.

From talking with dozens of dealers and wholesalers, three priorities come up again and again:

· Speed – stock availability and fast dispatch make or break a supply chain.

· Customization – many end users face unique dimensions; the supplier must be able to adapt.

· Technical backup – having experts to talk through an issue is as important as the product itself.

At NQKSF, these points shaped the way we work. We keep thousands of O-rings, seals, and kits on hand for immediate delivery. We also handle custom runs, from material selection through prototype testing. And with 30+ years of hands-on projects behind us, our team can suggest system-level optimizations, not just ship a part number.

Why NQKSF?

The sealing market is crowded. So why do global brands and local distributors continue to work with us?

· We are a manufacturing company, not a pure trading office, so production and delivery are under direct control.

· Recognized as one of the leaders in sealing technology, with a full product range and broad inventory.

· Products are shipped to over 80 countries, supplying both OEMs and aftermarket needs.

· Certified as a provincial technology innovation center, specialized & innovative enterprise, and high-tech company.

· Located in one of China’s most advanced industrial clusters, giving us access to strong supply chain support.

These are not just badges; they reflect how customers experience smoother cooperation. One overseas distributor once told me the main reason they chose us was simple: “When we hit a problem, there’s someone to solve it instead of passing the buck.”

Where They Are Used

Combination seals are found anywhere equipment cannot afford leaks or downtime:

· Hydraulic pumps and motors

· Gearboxes and engines

· Construction and agricultural machinery

· Metallurgy and chemical equipment

· Wind turbines and renewable energy

· Transportation: rail, marine, heavy trucks

All these sectors share one reality—downtime is expensive. A small seal failure can cause huge maintenance costs. The role of combination seals is to minimize that risk.

Questions Buyers Often Ask

Q: Can combination seals replace O-rings?

A: Not entirely. O-rings remain the most universal solution, but when pressure is high or movement is large, combination seals are more reliable.

Q: What about lead times for bulk orders?

A: Standard items are dispatched the same day. Customized solutions typically take two to three weeks.

Q: How do you help distributors avoid overstocking?

A: We provide phased deliveries and advice on which dimensions are most in demand, keeping inventory healthy.

Combination seals are not a brand-new invention, but they fill the gaps that traditional single-element seals cannot. For equipment manufacturers, they mean reliability. For distributors, they mean stronger competitiveness. For us in the sealing trade, they represent a smarter way of thinking—leveraging materials and design, rather than pushing any single product.