NB Series Internal Gear Pump | NB3-C50F NB3-D25F NB3-G25F NB3-C63F | High Pressure Low Noise Pump

The NB Series Internal Gear Pumps by Chengyuan Hydraulic are high-pressure, low-pulsation power components engineered for sophisticated industrial hydraulic systems. This series (e.g., NB3-C50F, NB3-G25F) is fully compatible with Sumitomo and other major internal gear pump standards, providing 100% original-place interchangeability. Featuring unique “Axial and Radial Pressure Compensation,” the NB series maintains exceptional volumetric efficiency even under continuous 25MPa operation. Its noise level is significantly lower than traditional external gear pumps, making it the ideal choice for injection molding machines and servo-driven hydraulic systems. Every unit undergoes 100% simulated condition testing to ensure mechanical stability under high-frequency response and long-term loads.

Technical Specifications :

• Representative Models: NB3-C50F, NB3-D25F, NB3-G25F, NB3-C63F

• Displacement Range: $25.0\text{ cm}^3\text{/rev}$ to $63.0\text{ cm}^3\text{/rev}$

• Rated Pressure: $25\text{ MPa (250 bar / 3625 psi)}$

• Maximum Peak Pressure: $31.5\text{ MPa (315 bar / 4568 psi)}$

• Operating Speed: $1800\text{–}2500\text{ rpm}$ (Servo drive compatible)

• Mounting Type: F (Flange mounting, typically Straight Key or Spline)

• Porting: SAE Flange Connection

• Noise Level: $\le 65\text{–}68\text{ dB(A)}$

Key Technical Advantages:

• Dual-Pressure Compensation: Utilizes floating side plates (axial) and flexible internal seals (radial). As system pressure increases, the sealing elements fit tighter, effectively controlling internal leakage and ensuring volumetric efficiency $\ge 95\%$ at $25\text{ MPa}$.

• Ultra-Low Flow Ripple & Noise: The high overlap ratio of the internal gear teeth results in a pressure ripple only $1/3$ that of standard pumps. This stable output significantly reduces system resonance noise and extends the fatigue life of pipes and actuators.

• Heavy-Duty Bearing Support: Equipped with special self-lubricating composite bearings and high-strength alloy steel gears. This configuration allows the NB series to withstand the mechanical shocks caused by rapid acceleration and deceleration in servo systems.

• Servo-Drive Compatibility: With low startup torque and high frequency response, the NB series is perfectly suited for synchronization with servo motors. It supports efficient low-speed operation during pressure-holding phases, a core requirement for energy-saving systems.

Application Areas:

• Injection Molding Machines: Primary pumps for clamping and injection, and pressure-holding circuits.

• Metalworking: CNC bending machines and precision hydraulic shears.

• Shoe & Rubber Machinery: Continuous pressure pump groups and multi-station rotary machines.

Expert Maintenance Tips:

• Inlet Vacuum Management: Due to its precision internal structure, the suction vacuum should not exceed $-0.2\text{ bar}$. Ensure the suction pipe has sufficient diameter and monitor filters with a vacuum gauge.

• Temperature Control: Maintain oil temperature between $30\text{°C}$ and $50\text{°C}$. Excessive heat can accelerate the aging of compensation seals, leading to a drop in output pressure.

• Air Bleeding: Before the initial startup, air must be exhausted through the pump body’s bleed plug. Trapped air in an internal gear pump can cause severe wear on the gear teeth within seconds.