U-Cup
Seals

Seals are a crucial part of industrial process equipment and help achieve the required safety levels during operation. U-cup seals offer airtight sealing pistons and rods in industrial processes. This lip seal type is useful for both static and dynamic applications. As the term implies, the cross-section of this seal type is U-shaped which helps the lips of the seal when the process pressure increases. Independence Seal Company offers u-cup seals in various designs and configurations, and each has its own benefits and suitability for specific applications. Our seals are made of premium-quality materials such as NBR, Viton, silicone, EPDM, FDA materials, and PTFE.

Overview of U-Cup Design

We offer various designs of U-cup seals, which can be customized or tailored for specific applications to get those unique advantages. We offer the u-cup seals in the following designs.

• Loaded U-Cups: These u–cup seals are primarily designed for dynamic reciprocating applications. The o-ring loader improves the lips’ seal performance with their sealing force when the system pressure increases; however, this type is also suitable for low-pressure rod and piston applications.
• Unloaded Urethane U-Cups: These u-cup seals provide a heavy-duty seal for both piston and rod applications. This seal type is suitable for both static and dynamic applications. They come in both single-lip and double-lip configurations. The double lip offers secondary sealing and additional stability, improving the seal performance.
• Homogenous U-Cups: This non-loaded type u-cup seal type is typically designed for low-pressure applications. They are widely used in pneumatic applications owing to their low friction seal. This u-cup seal is suitable in compact spaces because of its design. They can usually handle pressure up to 500 psi.
• DZ Seals: These are squeeze-type u-cup seals widely used for heavy-duty rod applications. They have a superior sealing ability and anti-extrusion characteristics, and low compression set.
• Spring Energized U-Cups: These are specially engineered plastic seals with a metallic spring that loads the seal lips against the mating hardware. This design compensates for movement in dynamic applications.

How to Select the Right U-Cup Seal for Your Application

When selecting the right u-cup seal, you need to consider various factors such as design elements. Here are some factors to help you select the right u-cup seal.

• General Design Elements: Design elements include the shape, form factor, color, and other such features. Form factor is especially essential depending on the space available.
• Fluid Media: It is necessary to check the chemical compatibility of the seal material with over 2,000 chemicals using a guide.
• Service Materials: Outline the importance of considering the minimum and maximum service temperature of a seal and fluids.
• System Pressure: This factor depends largely on the seal material and its ability to withstand a certain pressure range.
• Gland Size and Fitment: This is especially required wherein a u-cup seal needs to be fitted into an existing system. Even for new systems, one can customize the u-cup seal in terms of size, profile, material, and so on.
• Operating Life of the Seal: Again, this depends on the basic features of the seal, its material, and exposure to and compatibility with various fluid media. The operational life also increases with regular inspection and maintenance schedules. The other factors that influence a seal’s lifespan are stroke, pressure, surface finish, speed, duty, cycle, and more.

Chart for U-Cup Seals Materials and Temperature Ranges

General Hardware Design Guidelines

Here are some important hardware design guidelines about u-seals.

When you require seals to achieve tight tolerances, you need to consider chamfer, gland radii, and tapers to facilitate ease of assembly and avoid damage to the seal.

• Chamfer is a type of bevel that serves as an edge when joining two faces of an object or two different objects. It is positioned at a certain angle, which helps ease out edges and aids in seal installation.
• When designing, it is important to consider leading-edge chamfers, surface finishes, required tolerances, and dimensions to prevent any damage to the seal.
• Appropriate surface finishes can contribute towards the longevity of a sealing system. The surface finish must neither be too rough or smooth as microscopic variations on the surface form recesses that hold an oil film between the lip seal and the surface. Rough surfaces will wear out the lip and cause leakage paths. On the other hand, excessively smooth surfaces may cause friction and wear out the seal.
• When installing, the seal and the concerned hardware must be cleaned to avoid contamination.
• It is recommended to remove burrs and sharp edges to prevent seal wear and threads must be masked with insertion tooling.
• You can snap the seal into its place by gently pushing it with your hand along the taper when installing.

It is important to select the right type of u-cup seal that fits your application requirement.  These seals can be suitable replacements for many OEM seals including:  Disogrin, Parker, Hallite, Freudenberg, NOK, SKF, Busak & Shambam, Merkel, and Trelleborg,  Our understanding of sealing mechanisms and materials, industrial processes and their requirements, bearings, and more enables us to design and develop customized u-cup seals that ensure optimal performance and durability. Contact us today to find the perfect u-cup seals that suffice your process needs.