Product Overview
The QX52-050/42-032R298 and the entire QX series are the 5th generation of Bucher Hydraulics internal gear pumps. This series has proven itself in over thirty years of service worldwide, with a straightforward and robust design that has been continuously improved.
The QX52-050/42-032R298 is a double pump (tandem) configuration, with the primary section delivering 50 cm³/rev and the secondary section 32 cm³/rev. Single pump displacements range from 3 to 500 cm³/rev, with maximum operating pressure up to 400 bar.
Featuring Bucher’s patented gear profile optimized through CAE simulation, the QX series achieves extremely low noise levels (< 75 dB(A)) and minimal flow and pressure pulsation. The internal ring gear is supported by a hydrodynamic/hydrostatic lubrication film, enabling operation at low viscosities or low and high speeds.
Every unit is manufactured to original equipment specifications, ensuring 100% drop-in interchangeability with genuine Bucher QX series pumps without any system modifications. Each pump undergoes rigorous 100% simulated duty-cycle testing to validate pressure-flow-efficiency performance curves.
Brand Disclaimer: This product is a high-quality compatible replacement engineered for full interchangeability with Bucher Hydraulics original equipment. All Bucher brand names and model codes are referenced solely to indicate compatibility and interchangeability. This product is manufactured by an independent producer and is not an original Bucher product.
Technical Specifications
QX52-050/42-032R298 (Double Pump)
Model Code: QX52-050/42-032R298
Brand Series: Bucher Hydraulics QX 5th Generation Internal Gear Pump
Product Type: Double Internal Gear Pump
Primary Section Displacement: 50 cm³/rev
Secondary Section Displacement: 32 cm³/rev
Continuous Operating Pressure: 250 bar
Intermittent Operating Pressure: 280 bar
Maximum Speed: 3,400 rpm
Volumetric Efficiency: Up to 98%
Rotation Direction: Right-hand (Clockwise / R)
Noise Level: < 75 dB(A)
Hydraulic Fluids: Mineral oil, HFB/HFC/HFD, fuels, biodegradable, low-viscosity fluids
Certifications: ATEX 2, ABS, DNV, GL, LR, NK
Housing Material: High-strength cast iron
Seals: NBR / FKM (Viton) optional
Mounting Flange: SAE / ISO standard options
QX Series Single Pump General Specifications
QX2 Series: 3–16 cm³/rev, 320 bar cont., 3,600 rpm max
QX3 Series: 10–32 cm³/rev, 360 bar cont., 3,400 rpm max
QX4 Series: 20–63 cm³/rev, 360 bar cont., 3,200 rpm max
QX5 Series: 40–100 cm³/rev, 340 bar cont., 3,000 rpm max
QX6 Series: 80–250 cm³/rev, 330 bar cont., 2,500 rpm max
QX8 Series: 160–450 cm³/rev, 330 bar cont., 1,800 rpm max
Key Technical Advantages
1. 5th Generation Internal Gear Technology – 98% Volumetric Efficiency
The QX series represents Bucher’s 5th generation internal gear pump technology, achieving volumetric efficiency up to 98%. CAE-optimized large sealing areas deliver higher efficiencies. As an internal gear pump, its efficiency significantly surpasses equivalent external gear pumps, making it ideal for injection molding machines, die casting machines, and other energy-sensitive industrial hydraulic systems.
2. Ultra-Low Noise & Pulsation – < 75 dB(A)
The patented Bucher gear profile, optimized through CAE simulation, delivers extremely low noise levels (< 75 dB(A)) and minimal flow and pressure pulsation. Even at high pressures and speeds, operation remains quiet. Particularly suitable for noise-sensitive environments such as cab-near installations, indoor industrial equipment, and urban operation machinery.
3. Hydrodynamic/Hydrostatic Lubrication Film – Ultra-Wide Speed & Viscosity Range
The internal ring gear is supported by a hydrodynamic/hydrostatic lubrication film, enabling operation at low viscosities or low and high speeds. QX pumps are suitable for variable speed drives, providing variable flow rates. The QXEHX series extends the speed range up to 6,050 rpm.
4. Ultra-High Pressure Capability – Up to 400 bar
QX series maximum operating pressure reaches 400 bar. QX5 series continuous pressure rating is 340 bar. Far exceeding standard gear pump pressure ratings, ensuring long-term reliability under high-pressure, high-frequency, continuous-duty operations.
5. Wide Media Compatibility & ATEX Certification
Compatible with mineral oil, HFB/HFC/HFD fire-resistant fluids, fuels, biodegradable fluids, and low-viscosity fluids. Certified with ATEX 2, ABS, DNV, GL, LR, NK approvals, suitable for hazardous areas (Ex h IIC T3/T4).
6. Modular Design – Flexible Multi-Section Expansion
QX series supports single, tandem, and triple pump configurations. Flexible combinations adapt to complex hydraulic systems requiring multiple independent flow circuits.
7. 100% Simulated Duty-Cycle Testing
Every pump is 100% tested on dedicated hydraulic test benches under simulated real-world operating conditions—validating pressure-flow characteristics and efficiency curves at rated pressure and full speed range—ensuring zero-defect, plug-and-play performance upon installation.
Application Areas
Injection Molding Machines: Servo hydraulic systems, energy-efficient oil pump systems
Pressure Die Casting Machines: High-pressure hydraulic systems
Hydraulic Forming Presses: Forging hydraulic systems
Machine Tools: CNC machines, machining center hydraulic systems
Elevator/Lift Drives: Hydraulic elevator systems
Plastics-processing Machinery: Extrusion molding machines
Wind Turbines: Lubrication and hydraulic systems
Stackers/Forklifts: Material handling equipment hydraulic systems
Expert Maintenance Tips
1. Fluid Cleanliness Control
Internal gear pumps are highly sensitive to fluid contamination. Maintain system fluid cleanliness to ISO 4406 19/17/14 or better. Install a ≤10 μm absolute filtration filter upstream of the inlet port to prevent particle contamination from damaging precision gear pairs and distribution components.
2. Inlet Line Requirements
Keep suction lines short and straight with adequate diameter—not less than the port size. Inlet pressure must be maintained between 0.8 – 2.0 bar (absolute) . Prevent cavitation from insufficient suction that could damage the internal ring gear and pinion.
3. Coupling Alignment Precision
Ensure pump shaft-to-drive shaft coaxiality deviation ≤0.05 mm and angular deviation ≤0.5° during installation. Flexible couplings are strongly recommended. If the drive involves sprockets or V-belt pulleys, an independent outboard bearing MUST be installed to protect the pump shaft.
4. First-Start Priming Procedure
Before initial startup, thoroughly bleed air through the drain port or a loosened outlet fitting. Perform 2–3 jog starts under no-load conditions (outlet open) until oil fills the pump cavity without air bubbles, then connect the load circuit for full operation.
5. Speed & Viscosity Matching
QX pumps are suitable for variable speed drives and can operate across a wide speed range. During cold starts when viscosity is high, ensure adequate suction conditions or preheat the fluid to prevent cavitation damage.
6. Rotation Direction Confirmation
“R” in the model code indicates right-hand (clockwise) rotation; “L” indicates left-hand (counterclockwise). Always verify that the drive motor/engine rotation matches the pump before installation.
