Sealing Excellence, Securing Industry

CFKS Heavy Duty DK Type Oil Seal 30*8*18 DK Piston Seal NBR DK Rubber Skeleton Oil Seal

The CFKS 30*8*18 DK Type Piston Seal is engineered to maintain system pressure and prevent fluid migration in pneumatic and medium-duty hydraulic cylinders. Featuring a precision-molded rubber sealing profile reinforced with a robust skeleton core, this oil seal balances low sliding friction with positive lip contact, preventing seal blow-out and dynamic bypass under cyclic pressure changes.

  • Heavy-Duty Profile: Integrated metal skeleton ensures tight housing fit and prevents seal distortion under pressure spikes.

  • Low Dynamic Friction: Optimized sealing lip geometry minimizes stick-slip effect for smooth piston actuation.

  • Versatile Fluid Compatibility: Standard NBR compound resists mineral-based hydraulic oils, grease, and air-lubricants.

Product Name CFKS DK Type Piston Oil Seal Specification 30*8*18 mm (Customized sizes available)
Material NBR / FKM / PU Feature High Pressure Resistance, Wear Resistant
Work Temperature -20℃ to 220℃ (Material Dependent) Usage Hydraulic Cylinders, Pneumatic Actuators, Pumps, Earthmoving Machinery, Machine Tool Pistons
Hardness 70 – 90 Shore A Type DK Piston Rubber Skeleton Seal

 

 

The DK type seal operates as a compact, dynamic piston seal designed primarily for reciprocating hydraulic and pneumatic systems. Unlike standard radial shaft seals, the dynamic lip of the DK profile engages directly against the cylinder bore wall. Its internal metal skeleton provides essential radial rigidity, preserving structural integrity when subjected to rapid back-and-forth strokes. Under system pressure, fluid forces energize the elastomeric lip against the dynamic contact interface, automatically scaling the radial sealing force relative to system pressure to eliminate fluid bypass.
 

 

Material specification dictates seal life in harsh industrial conditions. The default high-grade NBR formulation provides high tensile strength, outstanding abrasion resistance, and excellent compatibility with petroleum-based hydraulic oils, lubricating greases, and water-glycol fluids across moderate operating temperatures. For high-temperature environments or aggressive chemical media (such as synthetic fluids and phosphate esters), FKM options are recommended, delivering superior thermal endurance and chemical stability to extend maintenance intervals.

 

Proper installation is essential to maximize seal life and maintain zero-leakage performance. Prior to fitting the 30*8*18 DK seal, inspect the piston groove and cylinder chamfer for burrs or sharp edges that could nick the elastomeric lip. Ensure the dynamic sealing lip faces the pressure source during assembly. Thanks to its rigid skeleton structure, the DK seal seats evenly without tilting inside the housing bore, reducing assembly time and helping maintain stable, long-term operation under heavy continuous cycles.

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.

 

MESSAGE

Go to Top