Cool under pressure

An innovative new seal design from a completely new material provides a solution for hydraulic sealing applications that are subject to increasingly higher pressures.

Machines, equipment and motors fitted with hydraulic cylinders are becoming more powerful, and that means the hydraulics are subject to higher pressures and temperatures. As a leading supplier of sealing solutions for fluid power applications, Trelleborg Sealing Solutions has responded by creating a unique seal in a material specially engineered for it: the Zurcon®Z13 Glyd Ring®D.

Resilient in the middle
“In the latest more powerful hydraulic applications, high pressure is combined with elevated temperatures,” says Jürgen Bauer, who works in product development at the Trelleborg Sealing Solutions headquarters in Stuttgart, Germany. “Our new Zurcon®polyurethane material is specially developed to cope with this combination, withstanding pressures up to 500 bar/ 7,250 psi at both sides and at temperatures up to +120 °C/ +248 °F.”

“We’ve developed a seal that has a long life, even under unforgiving conditions,” says Alberto Livi, Trelleborg Sealing Solutions product manager for Livorno, Italy, where the seal is manufactured. “Zurcon®Z13 polyurethane material was developed specifically for the new Glyd Ring®D seal. It offers superb mechanical and elastic properties. Not only does that make it ideal for working at extreme pressures in high temperatures but also means it loses none of its resilience. In fact, this material is so resilient it can also be used in cylinders with lower quality inner walls.”

Solving mobile hydraulic sealing challenges
Core industrial applications for Zurcon® Z13 Glyd Ring® D include construction machinery, earthmoving equipment, mobile cranes, forklift trucks and any other solutions involving mobile hydraulics. Cranes are becoming increasingly powerful and their hydraulic circuits have to work under greater pressure. For applications such as the hydraulic cylinders in the crane, Zurcon® Z13 Glyd Ring® D delivers a superb combination of elasticity and tensile strength, without compromising sliding friction properties.

Features and benefits:
• Excellent seal performance
• Prevents blow-by effects
• Compatible with the latest hydraulic fluids
• Tolerant of lower quality surfaces
• Withstands pressures up to 50 MPa/ 500 bar/ 7,250 psi
• Operates at sustained pressures up to 40 MPa/ 400 bar/ 5,800 psi with peak up to 55 MPa/ 550 bar/ 7,975 psi
• Able to operate effectively with pressure from both sides
• Minimum friction
• Maximum wear resistance

ZURCON® Z13
• Superior resilience
• Excellent friction properties
• Operating temperatures up to +120 °C/ +248 °F
• Compatible with hydraulic fluids
• 60 Shore D hardness
• Outstanding wear resistance
• Tolerant against lower quality mating surfaces
• Good extrusion properties
• Hydrolysis resistant

Fluid power
Many industries are improved by standards, but for a field as demanding and diverse as fluid power, the benefits are many, both to manufacturers and customers.
Standardization allows product interchangability and integration, guarantees certain performance characteristics and provides a framework for designers and engineers to exchange ideas. They indirectly educate and simplify use of hydraulic systems, enhance market competitiveness and promote new product development.

Broadly, the standards can be grouped into three categories: communication standards, design standards and performance standards.

Communication standards relate to interactions between designers, manufacturers and customers. These standards cover diagrams, terminology and symbols and simplify communications between interested parties. Importantly, circuit diagrams are covered by these standards, allowing anyone with knowledge of fluid power to correctly install a system.
Design standards aid engineers by standardizing aspects of the hardware and components of a hydraulic system. This prescribes tolerances, dimensions and hydraulic fluids enabling products which may be interchanged between systems to enhances competitiveness within the marketplace.
Performance standards help to ensure the reliability of a hydraulic system, providing assurance to a customer that a certain level of performance can be expected. These help to avoid costly mistakes and optimize system performance.