Sealing Excellence, Securing Industry

CFKS Dowty Washer NBR Bonded Seal for High Pressure Hydraulic Hose

The CFKS NBR Bonded Seal (Dowty Washer) is a critical static boundary component engineered explicitly for terminating high-pressure hydraulic hoses. By vulcanizing a trapezoidal Nitrile (NBR) sealing lip to a rigid, high-tensile metal outer ring, this composite gasket provides an impenetrable, vibration-proof seal for BSPP (British Standard Pipe Parallel) and metric hose fittings, completely eliminating the fluid weepage associated with standard metal crush washers.

  • Extreme Extrusion Resistance: The rigid metal outer ring acts as a structural back-up, preventing the NBR lip from blowing out under severe hydraulic impulse spikes.

  • Vibration and Whip Tolerant: Absorbs the high-frequency mechanical vibration and physical “whip” of pressurized hydraulic hoses without compromising the fluid boundary.

  • Optimized Fluid Compatibility: High-density NBR matrix actively resists degradation from standard mineral-based hydraulic oils and lubricants.

Find your sealing solution with CFKS — contact us for a quote.

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

 

Connecting a flexible, high-pressure hydraulic hose to a rigid manifold presents a severe engineering challenge. As valves open and close, the hose undergoes violent pressure impulses (often spiking from 0 to over 10,000 PSI in milliseconds) causing it to physically whip and vibrate. A standard annealed copper washer cannot compensate for this dynamic movement and will eventually weep fluid. The CFKS Bonded Seal utilizes a pressure-energized hydrodynamic design to solve this. When the hose fitting is torqued down, the trapezoidal NBR inner ring compresses. As fluid pressure spikes, it actively forces the elastomeric rubber outward against the unyielding metal shell. This allows the seal to maintain a flawless, micro-flexible boundary that easily absorbs hose vibration without extruding or failing.

The dynamic inner sealing element is molded from a highly cross-linked Nitrile Butadiene Rubber (NBR). This optimized elastomeric matrix is strictly engineered for standard mineral-based hydraulic oils, water-glycol fluids, and pneumatic systems operating in temperatures up to 100°C. It actively resists the chemical degradation, hardening, and structural swelling that destroy inferior commercial rubbers, ensuring a bone-dry static joint for the lifespan of the hose assembly.

From a heavy equipment maintenance perspective, terminating hydraulic hoses with CFKS bonded seals offers a massive mechanical advantage: they require significantly lower assembly torque than traditional solid metal crush washers. Because the elastomeric NBR lip achieves the actual fluid seal, technicians do not have to apply massive torque to physically crush solid metal. This preserves the internal threads on expensive directional control valves, hydraulic pumps, and the hose fittings themselves, completely preventing costly thread galling during emergency field repairs.

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.

CFKS Seal Manufacturing Co., Ltd.
https://cfksseals.com/
 Email: cfksnacy@gmail.com  Mobile/WhatsApp/Wechat: (86) 188-3097-5917
Bonded Seal Size List
MIDInner diameter toleranceODOuter Diameter ToleranceApplicable Thread
66.4±0.1212±0.12M6
88.414M8
1010.416M10(G1/8")
1212.418M12
1414.420±0.15M14(G1/4")
1616.422M16
1818.425M18(G3/8")
2020.5±0.1428M20
2222.530M22(G1/2)
2424.532±0.20M24
2727.535M27(G3/4")
3030.538M30
3333.5±0.1742M33(G1)
3636.646M36
3939.650M39
4242.653±0.25M42(G11/4)
4545.656M45
4848.760M48(G11/2)
5252.7±0.2066M52
6060.775M60(G2")

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