HYDAC NBR20 Accumulator Bladder Replacement | 6L 13L 20L 24L

The NBR20 Series accumulator bladders produced by Chengyuan Hydraulic are premium, elastomeric sealing components engineered to precisely replace the historical performance standards of German HYDAC bladder accumulators. This specialized series covers standard European capacities including NBR20 6L, NBR20 13L, NBR20 20L, and NBR20 24L.

As the core storage and pulsation-dampening element in hydraulic circuits, a bladder’s compound formulation dictates system integrity. Chengyuan guarantees 100% original-place interchangeability regarding precise geometric contours, gas valve layouts (7/8-14UNF standard or metric options), and volumetric expansion profiles. Every bladder is subjected to 100% digital gas-tightness verification and micro-defect detection before shipping, ensuring optimal gas retention and eliminating risk of hydraulic oil degradation.

Technical Specifications

• Compatible Brand: HYDAC Bladder Accumulators (Standard Series)

• Core Model Codes: NBR20-6L, NBR20-13L, NBR20-20L, NBR20-24L

• Nominal Capacity: 6 Liters / 13 Liters / 20 Liters / 24 Liters

• Bladder Material: High-elasticity NBR20 (Acrylonitrile Butadiene Rubber to European Standards)

• Fluid Compatibility: Mineral oils, water-glycols, and common hydraulic fluids

• Maximum Working Pressure: 350 bar (35 MPa)

• Pre-charge Ratio ($P_0$): Maximum recommended $\le 0.9 \times P_1$ (minimum system operating pressure)

• Temperature Range: -15°C to +80°C

• Gas Port Interface: 7/8-14 UNF thread (M28×1.5 available upon request)

Key Technical Advantages:

• High-Density European NBR20 Formula: Formulated with premium imported polymers optimized for critical Acrylonitrile (ACN) content. This material creates a high-density molecular matrix that reduces Nitrogen gas permeation by over 45% compared to generic aftermarket variants, extending system maintenance intervals.

• One-Piece Integrated Vulcanization Process: The rubber body and heavy-duty metal gas valve are molecularly bonded via an advanced one-shot compression molding process. This eliminates vulnerable seams or spliced weak points, ensuring exceptional stress distribution during high-frequency cycling.

• Minimal Hysteresis & Heat Build-up: Selected anti-wear compounding agents minimize internal molecular friction under rapid pulsation conditions (up to 400 cycles/min). This prevents localized overheating and elastomer carbonization, maintaining elasticity under severe thermal stress.

• Micron-Level Surface Finish Inspection: The exterior skin features a low-friction chemical coating to reduce abrasive wear against the steel accumulator shell. Combined with sophisticated high-pressure bench testing, we ensure flaw-free physical properties under peak hydraulic shocks.

Application Areas:

• Metallurgical & Casting Machinery: Auxiliary energy storage and high-response circuits for blast furnaces and continuous casting lines.

• Industrial Machine Tools: Pressure compensation and vibration dampening for high-tonnage bending and forging presses.

• Wind Energy Systems: Emergency power supply for hydraulic pitch control and yaw braking systems.

Expert Maintenance Tips:

• Pre-charging Gas Mandatory Regulation: Never pre-charge the bladder with oxygen or combustible gases. Only use industrial-grade Nitrogen ($N_2$) with a purity of $\ge 99.99\%$ to eliminate the risk of physical explosion.

• Pre-charge Pressure Parameter Check: Pre-charging must be performed with zero hydraulic pressure on the fluid side. The pre-charge pressure ($P_0$) must not exceed $90\%$ of the maximum system pressure, and should not fall below $25\%$ of the minimum system pressure to prevent the bladder from being crushed against the fluid port valve.

• Mandatory Installation Lubrication: Before folding and inserting the replacement bladder into the steel shell, evenly coat the bladder’s exterior and the shell’s interior with clean hydraulic oil of the same grade. Never assemble dry, as raw friction against internal edges can cause immediate structural scoring.