Reliable Sealing Solutions with UN Rod Seal Series for Hydraulic Applications

In today’s high-pressure industrial environments, effective sealing is essential to ensure system stability, reduce energy loss, and prevent fluid contamination. The UN rod seal series, made primarily from high-performance polyurethane (PU), is specifically engineered for hydraulic cylinder applications, especially in reciprocating motion systems. Designed for durability and optimized sealing, the UN series — including UN, UNS, and UHS models — plays a critical role in extending equipment life and improving operational efficiency across a wide range of industries.

At NQKSF, we combine three decades of sealing expertise with intelligent manufacturing to provide customers worldwide with both standard-stock and custom-engineered sealing solutions.

What is the UN Rod Seal Series?

The UN series is a group of U-cup style rod seals used to seal the reciprocating motion of hydraulic pistons, specifically the piston rod. These seals are characterized by a symmetrical lip design that ensures reliable sealing in both static and dynamic conditions. The series includes:

· UN – The standard type suitable for most hydraulic cylinder rod sealing needs. It features excellent sealing capability, long service life, and ease of installation.

· UNS – A short-type variant designed for limited axial space. It provides the same sealing function as the standard UN but with a lower profile for compact assemblies.

· UHS – A heavy-duty version with enhanced stability and wear resistance, ideal for high-load applications such as construction or mining equipment.

Each of these seal types is tailored to a different mechanical setup while maintaining a core function: preventing hydraulic fluid from escaping the system and external contaminants from entering.

Why Polyurethane (PU) Is the Material of Choice

Polyurethane is the predominant material for the UN series due to its outstanding mechanical and chemical characteristics. At NQKSF, we use premium-grade PU compounds that deliver the following advantages:

· Exceptional wear resistance, even under severe conditions

· High tensile strength and elasticity, enabling reliable sealing under pressure

· Excellent resistance to hydraulic oils and mineral-based fluids

· Operational temperature range from -35°C to +110°C (depending on formulation)

· Low compression set, which maintains long-term sealing performance

While NBR or PTFE may be used in specific custom designs, PU remains the optimal standard for dynamic rod seals in hydraulic systems.

Industries That Rely on UN Seals

The UN rod seal series is widely used in systems where hydraulic motion control is critical. Its design and performance make it ideal for:

· Hydraulic Cylinders – Industrial cylinders for automation, logistics, and processing equipment

· Construction Machinery – Excavators, bulldozers, cranes, and hydraulic arms

· Agricultural Equipment – Tractors, sprayers, and harvesters operating in dirty, outdoor conditions

· Industrial Robots and Machinery – Automated production lines requiring precise and durable sealing

· Material Handling Systems – Forklifts, hydraulic lifts, presses, and compactors

· Energy Sector – Wind turbine pitch control, hydroelectric equipment, and oil drilling systems

· Mining and Metallurgy – Heavy-duty machines working under high mechanical load and pressure

UN seals provide reliable sealing over long duty cycles, even in demanding environments involving vibration, dust, heat, and pressure variation.

Service That Goes Beyond Products

At NQKSF, we deliver more than just sealing components—we provide a complete sealing ecosystem backed by experience and reliability.

Fast Shipment of Standard Components

With over 10,000 SKU types in inventory, including O-rings, oil seals, and PU rod seals, we respond quickly to urgent needs. Our intelligent logistics network ensures fast dispatch worldwide.

Comprehensive Customization

From material selection and profile redesign to prototype testing, our engineering team works closely with customers to develop seals that perfectly match the demands of specific applications.

Technology-Driven System Solutions

Drawing on over 30 years of expertise, we help optimize entire sealing systems to enhance performance, reduce downtime, and lower maintenance costs for complex hydraulic machinery.

Why Global Clients Trust NQKSF

As a high-tech, innovation-driven enterprise, NQKSF has built a strong international reputation in the sealing industry through a commitment to excellence, backed by:

· A fully integrated smart manufacturing facility

· Full-model inventory coverage for global equipment compatibility

· Exports to over 80 countries

· Provincial Innovation Center Certification

· Recognition as a “Specialized and Innovative” enterprise

· National High-Tech Enterprise Status

· A key enterprise within the regional functional seal industry cluster

These strengths allow us to respond flexibly to both large-scale industrial clients and precision-focused OEM partners.

When systems depend on fluid integrity and motion precision, a failure in sealing can lead to costly consequences. The UN rod seal series, crafted with care and precision by NQKSF, offers a trusted solution for modern hydraulic systems. With optimized PU materials, proven profiles, and dependable sealing performance, the UN, UNS, and UHS seals ensure your machinery performs safely, smoothly, and efficiently.

Whether you're managing agricultural machinery in harsh environments or operating advanced industrial robots, NQKSF delivers not only products but peace of mind—through consistent quality, responsive support, and deep sealing system insight.