Sealing Excellence, Securing Industry

CFKS Hydraulic NBR UPH Oil Seal 20*30*8 UPH Seal Ring for Pump Seal

The CFKS 20*30*8 UPH Seal is a premium-grade, symmetrical U-cup designed for high-reliability sealing in hydraulic pumps and small-bore cylinders. Manufactured from high-density Nitrile (NBR), this 20*30*8 mm seal ring provides a versatile solution for both piston and rod sealing, ensuring a leak-proof interface under high-frequency cycling.Symmetrical Lip Profile: Identical inner and outer lips allow for universal installation on shafts or pistons.Optimized for Pumps: Low-friction NBR compound reduces torque requirements and heat buildup in pump glands.Standard 8 mm Height: Precision-molded to fit industry-standard 20*30 mm grooves with excellent stability.

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Brand Name CFKS OEM  Accpetable
Material NBR FKM Silicone  Features  wear resistance
Dimensions Customized Certificate  ISO9001/TS16949
Type UPH Oil Seal   Packing 1 pc per bag

 

The CFKS UPH seal utilizes a symmetrical U-shape cross-section that acts as a pressure-energized gasket. Unlike single-purpose seals, the UPH’s equal-length lips ensure that radial force is applied evenly to both the static groove and the dynamic sliding surface. In hydraulic pump applications, where pressure fluctuations are rapid, the internal “U” cavity captures the fluid energy, forcing the lips outward to maintain a positive seal even at low pressures. This geometry is particularly effective at preventing “air ingestion” during the suction stroke of a pump.

For standard hydraulic pumps operating with mineral oils, our 90 Shore A Nitrile (NBR) compound is the engineered choice. This material provides the ideal balance between elasticity and mechanical strength, resisting “extrusion” at pressures up to 31.5 MPa (315 Bar). The high-density NBR formulation is specifically treated to offer superior abrasion resistance against polished shafts, maintaining its sealing edge across a temperature range of -30°C to +100°C. This ensures the seal does not harden or “glaze” under the localized thermal loads common in high-RPM pump environments.

From a maintenance perspective, the 20*30*8 UPH is designed for a “snap-in” fit, significantly reducing assembly time during pump overhauls. Because it is a universal seal, it eliminates the risk of “backwards” installation common with asymmetric rod or piston seals. To ensure maximum service life, we recommend a shaft surface finish of 0.2 to 0.4 μm Ra. During installation, applying a light coat of hydraulic oil or lithium grease to the lips is essential to prevent “dry-start” wear, which is the leading cause of premature seal failure in newly commissioned pumps.

Frequently Asked Questions (FAQ)

Why does my CFKS oil seal fail prematurely? Common causes and prevention tips2025-06-26T15:44:39+08:00

Premature oil seal failure can result from improper installation, poor shaft finish, incorrect material selection, or excessive pressure. To prevent this, ensure the shaft surface is smooth and within tolerance, use correct tools during installation, and choose seals made from materials compatible with your media and temperature.

How to correctly install a CFKS industrial oil seal to avoid leakage2025-06-26T16:04:32+08:00

Always clean the shaft and bore before installation. Use appropriate seal drivers to avoid deformation. Lubricate the lip before fitting to reduce friction during the first rotation. Ensure the seal is seated evenly and not tilted to avoid leaks.

What to do when your CFKS hydraulic seal is leaking under pressure2025-05-20T16:33:14+08:00

Check if the pressure exceeds the seal’s rated limit. Examine for wear, hardening, or improper installation. Replace the seal if damaged, and consider upgrading to a high-pressure CFKS seal variant. Also, verify that the housing and shaft are properly aligned.

How to choose the right CFKS oil seal for extreme operating environments2025-05-20T16:34:39+08:00

For high temperatures, aggressive chemicals, or abrasive environments, choose CFKS seals made of FKM, PTFE, or high-performance elastomers. Consider using seals with protective dust lips or metal casing. Our team can recommend the best fit for your application.

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